Modelling Conditional and Unconditional Heteroskedasticity with Smoothly Time-Varying Structure

DEFF Research Database (Denmark)

Amado, Christina; Teräsvirta, Timo

multiplier type misspecification tests. Finite-sample properties of these procedures and tests are examined by simulation. An empirical application to daily stock returns and another one to daily exchange rate returns illustrate the functioning and properties of our modelling strategy in practice......In this paper, we propose two parametric alternatives to the standard GARCH model. They allow the conditional variance to have a smooth time-varying structure of either ad- ditive or multiplicative type. The suggested parameterizations describe both nonlinearity and structural change...... in the conditional and unconditional variances where the transition between regimes over time is smooth. A modelling strategy for these new time-varying parameter GARCH models is developed. It relies on a sequence of Lagrange multiplier tests, and the adequacy of the estimated models is investigated by Lagrange...

Winter feeding, growth and condition of brown trout Salmo trutta in a groundwater-dominated stream

Science.gov (United States)

French, William E.; Vondracek, Bruce C.; Ferrington, Leonard C.; Finlay, Jacques C.; Dieterman, Douglas J.

2014-01-01

Winter can be a stressful period for stream-dwelling salmonid populations, often resulting in reduced growth and survival. Stream water temperatures have been identified as a primary mechanism driving reductions in fitness during winter. However, groundwater inputs can moderate water temperature and may reduce winter severity. Additionally, seasonal reductions in prey availability may contribute to decreased growth and survival, although few studies have examined food webs supporting salmonids under winter conditions. This study employed diet, stable isotope, and mark-recapture techniques to examine winter (November through March) feeding, growth, and condition of brown troutSalmo trutta in a groundwater-dominated stream (Badger Creek, Minnesota, USA). Growth was greater for fish ≤ 150 mm (mean = 4.1 mg g−1 day−1) than for those 151–276 mm (mean = 1.0 mg g−1 day−1) during the winter season. Overall condition from early winter to late winter did not vary for fish ≤150 mm (mean relative weight (Wr) = 89.5) and increased for those 151–276 mm (mean Wr = 85.8 early and 89.4 late). Although composition varied both temporally and by individual, brown trout diets were dominated by aquatic invertebrates, primarily Amphipods, Dipterans, and Trichopterans. Stable isotope analysis supported the observations of the dominant prey taxa in stomach contents and indicated the winter food web was supported by a combination of allochthonous inputs and aquatic macrophytes. Brown trout in Badger Creek likely benefited from the thermal regime and increased prey abundance present in this groundwater-dominated stream during winter.

Growth of 2D and 3D plane cracks under thermo-mechanical loading with varying amplitudes

International Nuclear Information System (INIS)

Sbitti, Amine

2009-01-01

After a presentation of the phenomenon of thermal fatigue (in industrial applications and nuclear plants), this research thesis reports the investigation of the growth and arrest of a 2D crack under thermal fatigue (temperature and stress distribution over thickness, calculation of stress intensity factors, laws of fatigue crack growth, growth under varying amplitude), and the investigation of 3D crack growth under cyclic loading with varying amplitudes (analytic and numerical calculation of stress intensity factors, variational formulation in failure mechanics, 3D crack propagation under fatigue, use of the Aster code, use of the extended finite element method or X-FEM). The author discusses the origin and influence of the 3D crack network under thermal fatigue

Vibration condition monitoring of planetary gearbox under varying external load

Energy Technology Data Exchange (ETDEWEB)

Bartelmus, W.; Zimroz, R. [Wroclaw University of Technology, Wroclaw (Poland)

2009-01-15

The paper shows that for condition monitoring of planetary gearboxes it is important to identify the external varying load condition. In the paper, systematic consideration has been taken of the influence of many factors on the vibration signals generated by a system in which a planetary gearbox is included. These considerations give the basis for vibration signal interpretation, development of the means of condition monitoring, and for the scenario of the degradation of the planetary gearbox. Real measured vibration signals obtained in the industrial environment are processed. The signals are recorded during normal operation of the diagnosed objects, namely planetary gearboxes, which are a part of the driving system used in a bucket wheel excavator, used in lignite mines. It has been found that the most important factor of the proper planetary gearbox condition is connected with perturbation of arm rotation, where an arm rotation gives rise to a specific vibration signal whose properties are depicted by a short-time Fourier transform (STFT) and Wigner-Ville distribution presented as a time-frequency map. The paper gives evidence that there are two dominant low-frequency causes that influence vibration signal modulation, i.e. the varying load, which comes from the nature of the bucket wheel digging process, and the arm/carrier rotation. These two causes determine the condition of the planetary gearboxes considered.

Remaining useful life estimation for deteriorating systems with time-varying operational conditions and condition-specific failure zones

Directory of Open Access Journals (Sweden)

Li Qi

2016-06-01

Full Text Available Dynamic time-varying operational conditions pose great challenge to the estimation of system remaining useful life (RUL for the deteriorating systems. This paper presents a method based on probabilistic and stochastic approaches to estimate system RUL for periodically monitored degradation processes with dynamic time-varying operational conditions and condition-specific failure zones. The method assumes that the degradation rate is influenced by specific operational condition and moreover, the transition between different operational conditions plays the most important role in affecting the degradation process. These operational conditions are assumed to evolve as a discrete-time Markov chain (DTMC. The failure thresholds are also determined by specific operational conditions and described as different failure zones. The 2008 PHM Conference Challenge Data is utilized to illustrate our method, which contains mass sensory signals related to the degradation process of a commercial turbofan engine. The RUL estimation method using the sensor measurements of a single sensor was first developed, and then multiple vital sensors were selected through a particular optimization procedure in order to increase the prediction accuracy. The effectiveness and advantages of the proposed method are presented in a comparison with existing methods for the same dataset.

Conditional CAPM: Time-varying Betas in the Brazilian Market

Directory of Open Access Journals (Sweden)

Frances Fischberg Blank

2014-10-01

Full Text Available The conditional CAPM is characterized by time-varying market beta. Based on state-space models approach, beta behavior can be modeled as a stochastic process dependent on conditioning variables related to business cycle and estimated using Kalman filter. This paper studies alternative models for portfolios sorted by size and book-to-market ratio in the Brazilian stock market and compares their adjustment to data. Asset pricing tests based on time-series and cross-sectional approaches are also implemented. A random walk process combined with conditioning variables is the preferred model, reducing pricing errors compared to unconditional CAPM, but the errors are still significant. Cross-sectional test show that book-to-market ratio becomes less relevant, but past returns still capture cross-section variation

Effect of Salicylic Acid on the Growth and Physiological Characteristics of Maize under Stress Conditions

International Nuclear Information System (INIS)

Manzoor, K.; Ilyas, N.; Batool, N.; Arshad, M.; Ahmad, B.

2015-01-01

Salicylic acid (SA) is a naturally occurring signaling molecule and growth regulator that enhances plant growth particularly in stress conditions. The present study was planned to evaluate the effects of different levels of SA on maize growth under drought and salt stress conditions. An experiment was conducted to test the morphological, physiological and biochemical changes in two cultivar of maize D-1184 and TG-8250. Varying levels of salicylic acid, i.e. 5mM, 10mM and 15mM were applied through foliar method. Exogenous applications of salicylic acid were done after 20 days of germination of the maize plants. Salicylic acid significantly affects root and shoot dry matter under drought and salt stress. Foliar application of SA significantly increased proline concentration (11 percentage and 12 percentage), amino acid accumulation (25 percentage and 18 percentage), relative water (17 percentage and 14 percentage) and Chlorophyll content. Overall, it can be concluded that SA at lower concentration is effective to minimize the effect of stress conditions. Maize cultivar TG-8250 showed better tolerance under drought and salt stress condition as compared to D-1184 cultivar. (author)

Genome-wide transcriptome analysis of soybean primary root under varying water-deficit conditions.

Science.gov (United States)

Song, Li; Prince, Silvas; Valliyodan, Babu; Joshi, Trupti; Maldonado dos Santos, Joao V; Wang, Jiaojiao; Lin, Li; Wan, Jinrong; Wang, Yongqin; Xu, Dong; Nguyen, Henry T

2016-01-15

Soybean is a major crop that provides an important source of protein and oil to humans and animals, but its production can be dramatically decreased by the occurrence of drought stress. Soybeans can survive drought stress if there is a robust and deep root system at the early vegetative growth stage. However, little is known about the genome-wide molecular mechanisms contributing to soybean root system architecture. This study was performed to gain knowledge on transcriptome changes and related molecular mechanisms contributing to soybean root development under water limited conditions. The soybean Williams 82 genotype was subjected to very mild stress (VMS), mild stress (MS) and severe stress (SS) conditions, as well as recovery from the severe stress after re-watering (SR). In total, 6,609 genes in the roots showed differential expression patterns in response to different water-deficit stress levels. Genes involved in hormone (Auxin/Ethylene), carbohydrate, and cell wall-related metabolism (XTH/lipid/flavonoids/lignin) pathways were differentially regulated in the soybean root system. Several transcription factors (TFs) regulating root growth and responses under varying water-deficit conditions were identified and the expression patterns of six TFs were found to be common across the stress levels. Further analysis on the whole plant level led to the finding of tissue-specific or water-deficit levels specific regulation of transcription factors. Analysis of the over-represented motif of different gene groups revealed several new cis-elements associated with different levels of water deficit. The expression patterns of 18 genes were confirmed byquantitative reverse transcription polymerase chain reaction method and demonstrated the accuracy and effectiveness of RNA-Seq. The primary root specific transcriptome in soybean can enable a better understanding of the root response to water deficit conditions. The genes detected in root tissues that were associated with

Differences in nutrient uptake capacity of the benthic filamentous algae Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. under varying N/P conditions.

Science.gov (United States)

Liu, Junzhuo; Vyverman, Wim

2015-03-01

The N/P ratio of wastewater can vary greatly and directly affect algal growth and nutrient removal process. Three benthic filamentous algae species Cladophora sp., Klebsormidium sp. and Pseudanabaena sp. were isolated from a periphyton bioreactor and cultured under laboratory conditions on varying N/P ratios to determine their ability to remove nitrate and phosphorus. The N/P ratio significantly influenced the algal growth and phosphorus uptake process. Appropriate N/P ratios for nitrogen and phosphorus removal were 5-15, 7-10 and 7-20 for Cladophora sp., Klebsormidium sp. and Pseudanabaena sp., respectively. Within these respective ranges, Cladophora sp. had the highest biomass production, while Pseudanabaena sp. had the highest nitrogen and phosphorus contents. This study indicated that Cladophora sp. had a high capacity of removing phosphorus from wastewaters of low N/P ratio, and Pseudanabaena sp. was highly suitable for removing nitrogen from wastewaters with high N/P ratio. Copyright © 2014 Elsevier Ltd. All rights reserved.

One-dimensional radionuclide transport under time-varying conditions

International Nuclear Information System (INIS)

Gelbard, F.; Olague, N.E.; Longsine, D.E.

1990-01-01

This paper discusses new analytical and numerical solutions presented for one-dimensional radionuclide transport under time-varying fluid-flow conditions including radioactive decay. The analytical solution assumes that all radionuclides have identical retardation factors, and is limited to instantaneous releases. The numerical solution does not have these limitations, but is tested against the limiting case given for the analytical solution. Reasonable agreement between the two solutions was found. Examples are given for the transport of a three-member radionuclide chain transported over distances and flow rates comparable to those reported for Yucca Mountain, the proposed disposal site for high-level nuclear waste

Growth and Survival of Some Probiotic Strains in Simulated Ice Cream Conditions

Science.gov (United States)

Homayouni, A.; Ehsani, M. R.; Azizi, A.; Razavi, S. H.; Yarmand, M. S.

A Completely Randomized Design (CRD) experiment was applied in triplicates to evaluate the survival of four probiotic strains in simulated ice cream conditions. The growth and survival rate of these probiotic strains (Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium bifidum and Bifidobacterium longum) in varying amount of sucrose (10, 15, 20 and 25%), oxygen scavenging components (0.05% L-cysteine and 0.05% L-ascorbate) and temperatures (4 and -20°C) during different periods of time (1, 2 and 3 months) were evaluated in MRS-broth medium. Optical density at 580 nm was used to measure growth. Lactobacilli strains proved to be highly resistant in comparison with Biffidobacteria strains. The viable cell number of Lactobacillus casei in different sucrose concentrations, different oxidoreduction potentials and refrigeration temperature was 1x1010, 2x108 and 5x107 cfu mL-1, respectively. Growth and survival rate of Lactobacillus casei showed to be the highest.

Conditioning biomass for microbial growth

Science.gov (United States)

Bodie, Elizabeth A; England, George

2015-03-31

The present invention relates to methods for improving the yield of microbial processes that use lignocellulose biomass as a nutrient source. The methods comprise conditioning a composition comprising lignocellulose biomass with an enzyme composition that comprises a phenol oxidizing enzyme. The conditioned composition can support a higher rate of growth of microorganisms in a process. In one embodiment, a laccase composition is used to condition lignocellulose biomass derived from non-woody plants, such as corn and sugar cane. The invention also encompasses methods for culturing microorganisms that are sensitive to inhibitory compounds in lignocellulose biomass. The invention further provides methods of making a product by culturing the production microorganisms in conditioned lignocellulose biomass.

Atmospheric particle formation in spatially and temporally varying conditions

Energy Technology Data Exchange (ETDEWEB)

Lauros, J.

2011-07-01

Atmospheric particles affect the radiation balance of the Earth and thus the climate. New particle formation from nucleation has been observed in diverse atmospheric conditions but the actual formation path is still unknown. The prevailing conditions can be exploited to evaluate proposed formation mechanisms. This study aims to improve our understanding of new particle formation from the view of atmospheric conditions. The role of atmospheric conditions on particle formation was studied by atmospheric measurements, theoretical model simulations and simulations based on observations. Two separate column models were further developed for aerosol and chemical simulations. Model simulations allowed us to expand the study from local conditions to varying conditions in the atmospheric boundary layer, while the long-term measurements described especially characteristic mean conditions associated with new particle formation. The observations show statistically significant difference in meteorological and back-ground aerosol conditions between observed event and non-event days. New particle formation above boreal forest is associated with strong convective activity, low humidity and low condensation sink. The probability of a particle formation event is predicted by an equation formulated for upper boundary layer conditions. The model simulations call into question if kinetic sulphuric acid induced nucleation is the primary particle formation mechanism in the presence of organic vapours. Simultaneously the simulations show that ignoring spatial and temporal variation in new particle formation studies may lead to faulty conclusions. On the other hand, the theoretical simulations indicate that short-scale variations in temperature and humidity unlikely have a significant effect on mean binary water sulphuric acid nucleation rate. The study emphasizes the significance of mixing and fluxes in particle formation studies, especially in the atmospheric boundary layer. The further

Parental care mitigates carry-over effects of poor early conditions on offspring growth

Science.gov (United States)

Auer, Sonya K.; Martin, Thomas E.

2017-01-01

Poor developmental conditions can have long-lasting negative effects on offspring phenotypes, but impacts often differ among species. Contrasting responses may reflect disparities in experimental protocols among single-species studies or inherent differences among species in their sensitivity to early conditions and/or ability to mitigate negative impacts. We used a common experimental protocol to assess and compare the role of parental care in mitigating effects of poor early conditions on offspring among 4 sympatric bird species in the wild. We experimentally induced low incubation temperatures and examined effects on embryonic developmental rates, hatching success, nestling growth rates, and parental responses. We examined the generality of these effects across 4 species that differ in their phylogenetic history, breeding ecology, and life histories. We found that cooling led to delayed hatching in all species, but carry-over effects on offspring differed among species. Parents of some but not all species increased their offspring provisioning rates in response to experimental cooling with critical benefits for offspring growth rates. Our study shows for the first time that species exhibit clear differences in the degree to which they are affected by poor early conditions. Observed differences among species demonstrate that parental care is a critical mechanism for mitigating potential negative effects on offspring and suggest that parental responses may be constrained to varying degrees by ecology and life histories.

Effects of enhanced UVB on growth and yield of alfalfa and soybean under field conditions

International Nuclear Information System (INIS)

Al-Oudat, M.; Baydon, S.A.; Mohamad, A.

1998-01-01

The effects of 20% increase of UVB on growth and yield of alfalfa (Medicago Sativa L.) and two cultivars of soybean (Glycine Max (L.) Mer) under field conditions have been investigated. The increase of UVB dose ranged between 1.746 and 7.112 J/cm 2 during experiment. The results showed that soybean yield decrease by 16% and 31% in A. 3803 and A. 2522 cultivars respectively, under UVB exposure. The dry weight and leaf area were sensitive in the A. 3803 cultivar, while they were tolerant in the A. 2522 cultivar. Alfalfa response to UVB varied during the different stages of growth, whereas the yield was 12% less in the exposed plants. (author)

Characterization of Transient Plasma Ignition Flame Kernel Growth for Varying Inlet Conditions

Science.gov (United States)

2009-12-01

from Intercity Manufacturing. Without their expertise in precision machining this thesis would not have been possible. Their countless hours spent...somewhere within the combustor due to the time required to produce the required conditions, and will be travelling at near Mach 5 speeds for most...atmospheric pressure. This sudden drop in pressure creates a rarefaction wave that travels forward in the combustor. The blowdown time for a 1 meter long

All three quinone species play distinct roles in ensuring optimal growth under aerobic and fermentative conditions in E. coli K12

Science.gov (United States)

Nitzschke, Annika

2018-01-01

The electron transport chain of E. coli contains three different quinone species, ubiquinone (UQ), menaquinone (MK) and demethylmenaquinone (DMK). The content and ratio of the different quinone species vary depending on the external conditions. To study the function of the different quinone species in more detail, strains with deletions preventing UQ synthesis, as well as MK and/or DMK synthesis were cultured under aerobic and anaerobic conditions. The strains were characterized with respect to growth and product synthesis. As quinones are also involved in the control of ArcB/A activity, we analyzed the phosphorylation state of the response regulator as well as the expression of selected genes.The data show reduced aerobic growth coupled to lactate production in the mutants defective in ubiquinone synthesis. This confirms the current assumption that ubiquinone is the main quinone under aerobic growth conditions. In the UQ mutant strains the amount of MK and DMK is significantly elevated. The strain synthesizing only DMK is less affected in growth than the strain synthesizing MK as well as DMK. An inhibitory effect of MK on aerobic growth due to increased oxidative stress is postulated.Under fermentative growth conditions the mutant synthesizing only UQ is severely impaired in growth. Obviously, UQ is not able to replace MK and DMK during anaerobic growth. Mutations affecting quinone synthesis have an impact on ArcA phosphorylation only under anaerobic conditions. ArcA phosphorylation is reduced in strains synthesizing only MK or MK plus DMK. PMID:29614086

Time-varying analysis of CO_2 emissions, energy consumption, and economic growth nexus: Statistical experience in next 11 countries

International Nuclear Information System (INIS)

Shahbaz, Muhammad; Mahalik, Mantu Kumar; Shah, Syed Hasanat; Sato, João Ricardo

2016-01-01

This paper detects the direction of causality among carbon dioxide (CO_2) emissions, energy consumption, and economic growth in Next 11 countries for the period 1972–2013. Changes in economic, energy, and environmental policies as well as regulatory and technological advancement over time, cause changes in the relationship among the variables. We use a novel approach i.e. time-varying Granger causality and find that economic growth is the cause of CO_2 emissions in Bangladesh and Egypt. Economic growth causes energy consumption in the Philippines, Turkey, and Vietnam but the feedback effect exists between energy consumption and economic growth in South Korea. In the cases of Indonesia and Turkey, we find the unidirectional time-varying Granger causality running from economic growth to CO_2 emissions thus validates the existence of the Environmental Kuznets Curve hypothesis, which indicates that economic growth is achievable at the minimal cost of environment. The paper gives new insights for policy makers to attain sustainable economic growth while maintaining long-run environmental quality.

Optimization of induction, subculture conditions, and growth kinetics of Angelica sinensis (Oliv.) Diels callus.

Science.gov (United States)

Huang, Bing; Han, Lijuan; Li, Shaomei; Yan, Chunyan

2015-01-01

Angelica sinensis (Oliv.) Diels is an important traditional Chinese medicine, and the medicinal position is its root. This perennial herb grows vigorously only in specific areas and the environment. Tissue culture induction of callus and plant regeneration is an important and effective way to obtain large scale cultures of A. sinensis. The objective was to optimize the inductive, subculture conditions, and growth kinetics of A. sinensis. Tissue culture conditions for A. sinensis were optimized using leaves and petioles (types I and II) as explants source. Murashige and Skoog (MS) and H media supplemented with 30 g/L sucrose, 7.5 g/L agar, and varying concentrations of plant growth regulators were used for callus induction. In addition, four different basal media supplemented with 1.0 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D), 0.2 mg/L 6-benzyladenine (BA) and 30 g/L sucrose were optimized for callus subculture. Finally, growth kinetics of A. sinensis cultured on different subculture media was investigated based on callus properties, including fresh weight, dry weight, medium pH, callus relative fresh weight growth, callus relative growth rate (CRGR), and sucrose content. MS medium supplemented with 5 mg/L α-naphthaleneacetic acid, 0.5 mg/L BA, 0.7 mg/L 2,4-D, 30 g/L sucrose and 7.5 g/L agar resulted in optimal callus induction in A. sinensis while petiole I was found as the best plant organ for callus induction. The B5 medium supplemented with 1.0 mg/L 2,4-D, 0.2 mg/L BA and 30 g/L sucrose displayed the best results in A. sinensis callus subculture assays. The optimized conditions could be one of the most potent methods for large-scale tissue culture of A. sinensis.

Modified atmospheric conditions controlling fungal growth on cheese

DEFF Research Database (Denmark)

Nielsen, Per Væggemose

1997-01-01

Effective control of fungal growth on cheese under storage conditions is of great concern for the dairy industry. Therefore we designed a research project together with the Danish dairy industry on modelling fungal growth on cheese as affected by the combined effect of storage conditions (O2 and CO......2 level, relative humidity and temperature) and the composition of the cheese. All fungal species commonly found on cheese, starter cultures as well as contaminants, were examined.The most important factors influencing fungal growth are temperature, water activity of the medium and the carbon...... a competitive advantage over other fungi in moist conditions with high carbon dioxide levels, such as inside a roquefort cheese or in gas tight grain storage. The key to success in food packaging is to recognise the food ecosystem, as it enables us to identify which micro...

Sex differences in in-group cooperation vary dynamically with competitive conditions and outcomes.

Science.gov (United States)

Bailey, Drew H; Winegard, Benjamin; Oxford, Jon; Geary, David C

2012-03-18

Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male) young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus). In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

Sex Differences in In-Group Cooperation Vary Dynamically with Competitive Conditions and Outcomes

Directory of Open Access Journals (Sweden)

Drew H. Bailey

2012-01-01

Full Text Available Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus. In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

Effect of NiO growth conditions on the bipolar resistance memory switching of Pt/NiO/SRO structure

International Nuclear Information System (INIS)

Kurnia, F.; Hadiyawarman, H.; Jung, C. U.; Liu, C. L.; Lee, S. B.; Yang, S. M.; Park, H. W.; Song, S. J.; Hwang, C. S.

2010-01-01

We deposited NiO thin films with SrRuO 3 bottom electrodes on SrTiO 3 (001) substrates by using pulsed laser deposition. The growth temperature and the oxygen pressure were varied in order to obtain NiO films with different structural and electrical properties. We investigated the I-V characteristics of the Pt/NiO/SRO structures and observed a strong dependence of bipolar resistance switching on the growth conditions of the NiO thin films. Stable bipolar memory resistance switching was observed only in the devices with NiO films deposited at 400 .deg. C and 10 mTorr of O 2 . The off-state I-V curve of bipolar switching showed a linear fitting to the Schottky effect, indicating its origin in the NiO/SRO interface. Our results suggest that the growth conditions of NiO may affect the bipolar switching behavior through the film's resistance, the film's crystallinity, or the status of the grain boundaries.

Conditions for mould growth on typical interior surfaces

DEFF Research Database (Denmark)

Møller, Eva B.; Andersen, Birgitte; Rode, Carsten

2017-01-01

Prediction of the risk for mould growth is an important parameter for the analysis and design of the hygrothermal performance of building constructions. However, in practice the mould growth does not always follow the predicted behavior described by the mould growth models. This is often explained...... by uncertainty in the real conditions of exposure. In this study, laboratory experiments were designed to determine mould growth at controlled transient climate compared to growth at constant climate. The experiment included three building materials with four different surface treatments. The samples were...

A thermal model for photovoltaic panels under varying atmospheric conditions

International Nuclear Information System (INIS)

Armstrong, S.; Hurley, W.G.

2010-01-01

The response of the photovoltaic (PV) panel temperature is dynamic with respect to the changes in the incoming solar radiation. During periods of rapidly changing conditions, a steady state model of the operating temperature cannot be justified because the response time of the PV panel temperature becomes significant due to its large thermal mass. Therefore, it is of interest to determine the thermal response time of the PV panel. Previous attempts to determine the thermal response time have used indoor measurements, controlling the wind flow over the surface of the panel with fans or conducting the experiments in darkness to avoid radiative heat loss effects. In real operating conditions, the effective PV panel temperature is subjected to randomly varying ambient temperature and fluctuating wind speeds and directions; parameters that are not replicated in controlled, indoor experiments. A new thermal model is proposed that incorporates atmospheric conditions; effects of PV panel material composition and mounting structure. Experimental results are presented which verify the thermal behaviour of a photovoltaic panel for low to strong winds.

Crack growth behaviour of low-alloy steels for pressure boundary components under transient light water reactor operating conditions - CASTOC, Part II: WWER conditions

Energy Technology Data Exchange (ETDEWEB)

Ernestova, M.; Zamboch, M. [Nuclear Research Institute, NRI, Rez (Czech Republic); Devrient, B.; Roth, A. [Framatome ANP GmbH, Erlangen (Germany); Ehrnsten, U. [VTT Industrial Systems, Espoo (Finland); Foehl, J.; Weissenberg, T. [Staatliche Materialpruefungsanstalt, MPA, Stuttgart (Germany); Gomez-Briceno, D.; Lapena, J. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, CIEMAT, Madrid (Spain); Ritter, S.; Seifert, H.P. [Paul Scherrer Institute, PSI, Villigen (Switzerland)

2004-07-01

One of the ageing phenomena of pressure boundary components of light water reactors (LWRs) is environmentally-assisted cracking (EAC). The project CASTOC (5. Framework Programme of the EU) was launched September 2000 with six European partners and terminated August 2003. It focused in particular on the EAC behaviour of low-alloy steels (LAS) and to some extent to weld metal, heat affected zone and the influence of an austenitic cladding. The main objective was directed to the clarification of crack growth behavior of LAS in high-temperature water due to EAC under constant load (steady-state power operation), to study the effect of transient conditions (during operation or start-up/shut-down of a plant) using their impact on time-based and cycle-based crack growth rates and to a more detailed understanding of the acting mechanisms. Autoclave tests were performed with Western and Russian type reactor pressure vessel steels under simulated boiling water reactor (BWR)/normal water chemistry (NWC) and pressurized water reactor (WWER) conditions. The investigations were performed with fracture mechanics specimens of different sizes and geometries. The applied loading comprised cyclic loads, static loads and load spectra where the static load was periodically interrupted by partial unloading. With regard to water chemistry, the oxygen content (WWER) and impurities of sulphate and chlorides (BWR) were varied beyond allowable limits for continuous operation. The current paper summarizes the most important crack growth results obtained under simulated WWER conditions. The influence of oxygen content and the effect of specimen size (C(T)25 versus C(T)50 specimens) on the crack growth rates are shown. The results are discussed in the context of the current crack growth rate curves in the corresponding nuclear codes. (authors)

Crack growth behaviour of low-alloy steels for pressure boundary components under transient light water reactor operating conditions - CASTOC, Part II: WWER conditions

International Nuclear Information System (INIS)

Ernestova, M.; Zamboch, M.; Devrient, B.; Roth, A.; Ehrnsten, U.; Foehl, J.; Weissenberg, T.; Gomez-Briceno, D.; Lapena, J.; Ritter, S.; Seifert, H.P.

2004-01-01

One of the ageing phenomena of pressure boundary components of light water reactors (LWRs) is environmentally-assisted cracking (EAC). The project CASTOC (5. Framework Programme of the EU) was launched September 2000 with six European partners and terminated August 2003. It focused in particular on the EAC behaviour of low-alloy steels (LAS) and to some extent to weld metal, heat affected zone and the influence of an austenitic cladding. The main objective was directed to the clarification of crack growth behavior of LAS in high-temperature water due to EAC under constant load (steady-state power operation), to study the effect of transient conditions (during operation or start-up/shut-down of a plant) using their impact on time-based and cycle-based crack growth rates and to a more detailed understanding of the acting mechanisms. Autoclave tests were performed with Western and Russian type reactor pressure vessel steels under simulated boiling water reactor (BWR)/normal water chemistry (NWC) and pressurized water reactor (WWER) conditions. The investigations were performed with fracture mechanics specimens of different sizes and geometries. The applied loading comprised cyclic loads, static loads and load spectra where the static load was periodically interrupted by partial unloading. With regard to water chemistry, the oxygen content (WWER) and impurities of sulphate and chlorides (BWR) were varied beyond allowable limits for continuous operation. The current paper summarizes the most important crack growth results obtained under simulated WWER conditions. The influence of oxygen content and the effect of specimen size (C(T)25 versus C(T)50 specimens) on the crack growth rates are shown. The results are discussed in the context of the current crack growth rate curves in the corresponding nuclear codes. (authors)

Convex variational problems linear, nearly linear and anisotropic growth conditions

CERN Document Server

Bildhauer, Michael

2003-01-01

The author emphasizes a non-uniform ellipticity condition as the main approach to regularity theory for solutions of convex variational problems with different types of non-standard growth conditions. This volume first focuses on elliptic variational problems with linear growth conditions. Here the notion of a "solution" is not obvious and the point of view has to be changed several times in order to get some deeper insight. Then the smoothness properties of solutions to convex anisotropic variational problems with superlinear growth are studied. In spite of the fundamental differences, a non-uniform ellipticity condition serves as the main tool towards a unified view of the regularity theory for both kinds of problems.

Clostridium tyrobutyricum strains show wide variation in growth at different NaCl, pH, and temperature conditions.

Science.gov (United States)

Ruusunen, Marjo; Surakka, Anu; Korkeala, Hannu; Lindström, Miia

2012-10-01

Outgrowth from Clostridium tyrobutyricum spores in milk can lead to butyric acid fermentation in cheeses, causing spoilage and economical loss to the dairy industry. The aim of this study was to investigate the growth of 10 C. tyrobutyricum strains at different NaCl, pH, and temperature conditions. Up to 7.5-fold differences among the maximum growth rates of different strains in the presence of 2.0% NaCl were observed. Five of 10 strains were able to grow in the presence of 3.0% NaCl, while a NaCl concentration of 3.5% was completely inhibitory to all strains. Seven of 10 strains were able to grow at pH 5.0, and up to 4- and 12.5-fold differences were observed among the maximum growth rates of different strains at pH 5.5 and 7.5, respectively. The maximum growth temperatures varied from 40.2 to 43.3°C. The temperature of 10°C inhibited the growth of all strains, while 8 of 10 strains grew at 12 and 15°C. Despite showing no growth, all strains were able to survive at 10°C. In conclusion, wide variation was observed among different C. tyrobutyricum strains in their ability to grow at different stressful conditions. Understanding the physiological diversity among the strains is important when designing food control measures and predictive models for the growth of spoilage organisms in cheese.

Growth and intraspecific competitive abilities of the dioecious Lindera melissifolia (Lauraceae) in varied flooding regimes

Science.gov (United States)

Tracy S. Hawkins; Nathan M. Schiff; Theodor D. Leininger; Emile S Gardiner; Margaret S. Devall; Paul B. Hamel; A. Dan Wilson; Kristina F. Connor

2009-01-01

Forest Service, Southern Research Station, Stoneville, MS 38776). Growth and intraspecific competitive abilities of the dioecious Lindera melissifolia (Lauraceae) in varied flooding regimes. J. Torrey Bot. Soc. 136: 91–101. 2009.—The contribution of sexual dimorphism to malebiased colony ratios observed in field populations of the federally...

Optimal growth conditions for Isochrysis galbana

Energy Technology Data Exchange (ETDEWEB)

Kaplan, D; Cohen, Z; Abeliovich, A

1986-01-01

Environmental and nutritional growth conditions of the unicellular microalga Isochrysis galbana were studied under laboratory conditions. The information obtained was used for cultivating the alga in outdoor miniponds. Outdoor cultures stayed monoalgal and free of predators as long as the temperature did not fall below 19 degrees C and the rate of dilution did not exceed 40% of the culture's volume. Isochrysis galbana grown in outdoor cultures provided lipid concentrations of 24-28% of ash free dry matter. 12 references.

Towards artificial intelligence based diesel engine performance control under varying operating conditions using support vector regression

Directory of Open Access Journals (Sweden)

Naradasu Kumar Ravi

2013-01-01

Full Text Available Diesel engine designers are constantly on the look-out for performance enhancement through efficient control of operating parameters. In this paper, the concept of an intelligent engine control system is proposed that seeks to ensure optimized performance under varying operating conditions. The concept is based on arriving at the optimum engine operating parameters to ensure the desired output in terms of efficiency. In addition, a Support Vector Machines based prediction model has been developed to predict the engine performance under varying operating conditions. Experiments were carried out at varying loads, compression ratios and amounts of exhaust gas recirculation using a variable compression ratio diesel engine for data acquisition. It was observed that the SVM model was able to predict the engine performance accurately.

Testing phenotypic trade-offs in the chemical defence strategy of Scots pine under growth-limiting field conditions.

Science.gov (United States)

Villari, Caterina; Faccoli, Massimo; Battisti, Andrea; Bonello, Pierluigi; Marini, Lorenzo

2014-09-01

Plants protect themselves from pathogens and herbivores through fine-tuned resource allocation, including trade-offs among resource investments to support constitutive and inducible defences. However, empirical research, especially concerning conifers growing under natural conditions, is still scarce. We investigated the complexity of constitutive and induced defences in a natural Scots pine (Pinus sylvestris L.) stand under growth-limiting conditions typical of alpine environments. Phenotypic trade-offs at three hierarchical levels were tested by investigating the behaviour of phenolic compounds and terpenoids of outer bark and phloem. We tested resource-derived phenotypic correlations between (i) constitutive and inducible defences vs tree ring growth, (ii) different constitutive defence metabolites and (iii) constitutive concentration and inducible variation of individual metabolites. Tree ring growth was positively correlated only with constitutive concentration of total terpenoids, and no overall phenotypic trade-offs between different constitutive defensive metabolites were found. At the lowest hierarchical level tested, i.e., at the level of relationship between constitutive and inducible variation of individual metabolites, we found that different compounds displayed different behaviours; we identified five different defensive metabolite response types, based on direction and strength of the response, regardless of tree age and growth rate. Therefore, under growth-limiting field conditions, Scots pine appears to utilize varied and complex outer bark and phloem defence chemistry, in which only part of the constitutive specialized metabolism is influenced by tree growth, and individual components do not appear to be expressed in a mutually exclusive manner in either constitutive or inducible metabolism. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Priority target conditions for algorithms for monitoring children's growth: Interdisciplinary consensus.

Directory of Open Access Journals (Sweden)

Pauline Scherdel

Full Text Available Growth monitoring of apparently healthy children aims at early detection of serious conditions through the use of both clinical expertise and algorithms that define abnormal growth. Optimization of growth monitoring requires standardization of the definition of abnormal growth, and the selection of the priority target conditions is a prerequisite of such standardization.To obtain a consensus about the priority target conditions for algorithms monitoring children's growth.We applied a formal consensus method with a modified version of the RAND/UCLA method, based on three phases (preparatory, literature review, and rating, with the participation of expert advisory groups from the relevant professional medical societies (ranging from primary care providers to hospital subspecialists as well as parent associations. We asked experts in the pilot (n = 11, reading (n = 8 and rating (n = 60 groups to complete the list of diagnostic classification of the European Society for Paediatric Endocrinology and then to select the conditions meeting the four predefined criteria of an ideal type of priority target condition.Strong agreement was obtained for the 8 conditions selected by the experts among the 133 possible: celiac disease, Crohn disease, craniopharyngioma, juvenile nephronophthisis, Turner syndrome, growth hormone deficiency with pituitary stalk interruption syndrome, infantile cystinosis, and hypothalamic-optochiasmatic astrocytoma (in decreasing order of agreement.This national consensus can be used to evaluate the algorithms currently suggested for growth monitoring. The method used for this national consensus could be re-used to obtain an international consensus.

Effects of growth conditions on thermal profiles during Czochralski silicon crystal growth

Science.gov (United States)

Choe, Kwang Su; Stefani, Jerry A.; Dettling, Theodore B.; Tien, John K.; Wallace, John P.

1991-01-01

An eddy current testing method was used to continuously monitor crystal growth process and investigate the effects of growth conditions on thermal profiles during Czochralski silicon crystal growth. The experimental concept was to monitor the intrinsic electrical conductivities of the growing crystal and deduce temperature values from them. In terms of the experiments, the effects of changes in growth parameters, which include the crystal and crucible rotation rates, crucible position, and pull rate, and hot-zone geometries were investigated. The results show that the crystal thermal profile could shift significantly as a function of crystal length if the closed-loop control fails to maintain a constant thermal condition. As a direct evidence to the effects of the melt flow on heat transfer processes, a thermal gradient minimum was observed when the crystal/crucible rotation combination was 20/-10 rpm cw. The thermal gradients in the crystal near the growth interface were reduced most by decreasing the pull rate or by reducing the radiant heat loss to the environment; a nearly constant axial thermal gradient was achieved when either the pull rate was decreased by half, the height of the exposed crucible wall was doubled, or a radiation shield was placed around the crystal. Under these conditions, the average axial thermal gradient along the surface of the crystal was about 4-5°C/mm. When compared to theoretical results found in literature, the axial profiles correlated well with the results of the models which included radiant interactions. However, the radial gradients estimated from three-frequency data were much higher than what were predicted by known theoretical models. This discrepancy seems to indicate that optical phenomenon within the crystal is significant and should be included in theoretical modeling.

Leading-Edge Noise Prediction of General Airfoil Profiles with Spanwise-Varying Inflow Conditions

NARCIS (Netherlands)

Miotto, Renato Fuzaro; Wolf, William Roberto; De Santana, Leandro Dantas

2018-01-01

This paper presents a study of the leading-edge noise radiated by an airfoil undergoing a turbulent inflow. The noise prediction of generic airfoil profiles subjected to spanwise-varying inflow conditions is performed with the support of Amiet’s theory and the inverse strip technique. In the

Leading-Edge Noise Prediction of General Airfoil Profiles with Spanwise-Varying Inflow Conditions

NARCIS (Netherlands)

Miotto, Renato Fuzaro; Wolf, William Roberto; De Santana, Leandro Dantas

This paper presents a study of the leading-edge noise radiated by an airfoil undergoing a turbulent inflow. The noise prediction of generic airfoil profiles subjected to spanwise-varying inflow conditions is performed with the support of Amiet’s theory and the inverse strip technique. In the

Nanoparticle growth and surface chemistry changes in cell-conditioned culture medium.

Science.gov (United States)

Kendall, Michaela; Hodges, Nikolas J; Whitwell, Harry; Tyrrell, Jess; Cangul, Hakan

2015-02-05

When biomolecules attach to engineered nanoparticle (ENP) surfaces, they confer the particles with a new biological identity. Physical format may also radically alter, changing ENP stability and agglomeration state within seconds. In order to measure which biomolecules are associated with early ENP growth, we studied ENPs in conditioned medium from A549 cell culture, using dynamic light scattering (DLS) and linear trap quadrupole electron transfer dissociation mass spectrometry. Two types of 100 nm polystyrene particles (one uncoated and one with an amine functionalized surface) were used to measure the influence of surface type. In identically prepared conditioned medium, agglomeration was visible in all samples after 1 h, but was variable, indicating inter-sample variability in secretion rates and extracellular medium conditions. In samples conditioned for 1 h or more, ENP agglomeration rates varied significantly. Agglomerate size measured by DLS was well correlated with surface sequestered peptide number for uncoated but not for amine coated polystyrene ENPs. Amine-coated ENPs grew much faster and into larger agglomerates associated with fewer sequestered peptides, but including significant sequestered lactose dehydrogenase. We conclude that interference with extracellular peptide balance and oxidoreductase activity via sequestration is worthy of further study, as increased oxidative stress via this new mechanism may be important for cell toxicity. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Crack growth behaviour of low-alloy steels for pressure boundary components under transient light water reactor operating conditions - CASTOC, Part I: BWR/NWC conditions

International Nuclear Information System (INIS)

Ritter, S.; Seifert, H.P.; Devrient, B.; Roth, A.; Ehrnsten, U.; Ernestova, M.; Zamboch, M.; Foehl, J.; Weissenberg, T.; Gomez-Briceno, D.; Lapena, J.

2004-01-01

One of the ageing phenomena of pressure boundary components of light water reactors (LWR) is environmentally-assisted cracking (EAC). The project CASTOC (5. Framework Programme of the EU) was launched September 2000 with six European partners and terminated August 2003. It was focused in particular on the EAC behaviour of low-alloy steels (LAS) and to some extent to weld metal, heat affected zone and the influence of an austenitic cladding. The main objective was directed to the clarification of EAC crack growth behaviour/mechanism of LAS in high-temperature water under steady-state power operation (constant load) and transient operating conditions (e.g., start-up/shut-down, transients in water chemistry and load). Autoclave tests were performed with Western and Russian type reactor pressure vessel steels under simulated boiling water reactor (BWR)/normal water chemistry (NWC) and pressurised water reactor (VVER) conditions. The investigations were performed with fracture mechanics specimens of different sizes and geometries. The applied loading comprised cyclic loads, static loads and load spectra where the static load was periodically interrupted by partial unloading. With regard to water chemistry, the oxygen content (VVER) and impurities of sulphate and chlorides (BWR) were varied beyond allowable limits for continuous operation. The current paper summarises the most important crack growth results obtained under simulated BWR/NWC conditions. The results are discussed in the context of the current crack growth rate curves in the corresponding nuclear codes. (authors)

Crack growth behaviour of low-alloy steels for pressure boundary components under transient light water reactor operating conditions - CASTOC, Part I: BWR/NWC conditions

Energy Technology Data Exchange (ETDEWEB)

Ritter, S.; Seifert, H.P. [Paul Scherrer Institute, PSI, Villigen (Switzerland); Devrient, B.; Roth, A. [Framatome ANP GmbH, Erlangen (Germany); Ehrnsten, U. [VTT Industrial Systems, Espoo (Finland); Ernestova, M.; Zamboch, M. [Nuclear Research Institute, NRI, Rez (Czech Republic); Foehl, J.; Weissenberg, T. [Staatliche Materialpruefungsanstalt, MPA, Stuttgart (Germany); Gomez-Briceno, D.; Lapena, J. [Centro de Investigaciones Energeticas Medioambientales y Tecnologicas, CIEMAT, Madrid (Spain)

2004-07-01

One of the ageing phenomena of pressure boundary components of light water reactors (LWR) is environmentally-assisted cracking (EAC). The project CASTOC (5. Framework Programme of the EU) was launched September 2000 with six European partners and terminated August 2003. It was focused in particular on the EAC behaviour of low-alloy steels (LAS) and to some extent to weld metal, heat affected zone and the influence of an austenitic cladding. The main objective was directed to the clarification of EAC crack growth behaviour/mechanism of LAS in high-temperature water under steady-state power operation (constant load) and transient operating conditions (e.g., start-up/shut-down, transients in water chemistry and load). Autoclave tests were performed with Western and Russian type reactor pressure vessel steels under simulated boiling water reactor (BWR)/normal water chemistry (NWC) and pressurised water reactor (VVER) conditions. The investigations were performed with fracture mechanics specimens of different sizes and geometries. The applied loading comprised cyclic loads, static loads and load spectra where the static load was periodically interrupted by partial unloading. With regard to water chemistry, the oxygen content (VVER) and impurities of sulphate and chlorides (BWR) were varied beyond allowable limits for continuous operation. The current paper summarises the most important crack growth results obtained under simulated BWR/NWC conditions. The results are discussed in the context of the current crack growth rate curves in the corresponding nuclear codes. (authors)

Applicability of common stomatal conductance models in maize under varying soil moisture conditions.

Science.gov (United States)

Wang, Qiuling; He, Qijin; Zhou, Guangsheng

2018-07-01

In the context of climate warming, the varying soil moisture caused by precipitation pattern change will affect the applicability of stomatal conductance models, thereby affecting the simulation accuracy of carbon-nitrogen-water cycles in ecosystems. We studied the applicability of four common stomatal conductance models including Jarvis, Ball-Woodrow-Berry (BWB), Ball-Berry-Leuning (BBL) and unified stomatal optimization (USO) models based on summer maize leaf gas exchange data from a soil moisture consecutive decrease manipulation experiment. The results showed that the USO model performed best, followed by the BBL model, BWB model, and the Jarvis model performed worst under varying soil moisture conditions. The effects of soil moisture made a difference in the relative performance among the models. By introducing a water response function, the performance of the Jarvis, BWB, and USO models improved, which decreased the normalized root mean square error (NRMSE) by 15.7%, 16.6% and 3.9%, respectively; however, the performance of the BBL model was negative, which increased the NRMSE by 5.3%. It was observed that the models of Jarvis, BWB, BBL and USO were applicable within different ranges of soil relative water content (i.e., 55%-65%, 56%-67%, 37%-79% and 37%-95%, respectively) based on the 95% confidence limits. Moreover, introducing a water response function, the applicability of the Jarvis and BWB models improved. The USO model performed best with or without introducing the water response function and was applicable under varying soil moisture conditions. Our results provide a basis for selecting appropriate stomatal conductance models under drought conditions. Copyright © 2018 Elsevier B.V. All rights reserved.

Seed banks as a source of vegetation regeneration to support the recovery of degraded rivers: A comparison of river reaches of varying condition.

Science.gov (United States)

O'Donnell, Jessica; Fryirs, Kirstie A; Leishman, Michelle R

2016-01-15

Anthropogenic disturbance has contributed to widespread geomorphic adjustment and the degradation of many rivers. This research compares for river reaches of varying condition, the potential for seed banks to support geomorphic river recovery through vegetation regeneration. Seven river reaches in the lower Hunter catchment of south-eastern Australia were assessed as being in poor, moderate, or good condition, based on geomorphic and ecological indicators. Seed bank composition within the channel and floodplain (determined in a seedling emergence study) was compared to standing vegetation. Seed bank potential for supporting geomorphic recovery was assessed by measuring native species richness, and the abundance of different plant growth forms, with consideration of the roles played by different growth forms in geomorphic adjustment. The exotic seed bank was considered a limiting factor for achieving ecological restoration goals, and similarly analysed. Seed bank native species richness was comparable between the reaches, and regardless of condition, early successional and pioneer herbs, sedges, grasses and rushes dominated the seed bank. The capacity for these growth forms to colonise and stabilise non-cohesive sediments and initiate biogeomorphic succession, indicates high potential for the seed banks of even highly degraded reaches to contribute to geomorphic river recovery. However, exotic propagules increasingly dominated the seed banks of moderate and poor condition reaches and reflected increasing encroachment by terrestrial exotic vegetation associated with riparian degradation. As the degree of riparian degradation increases, the resources required to control the regeneration of exotic species will similarly increase, if seed bank-based regeneration is to contribute to both geomorphic and ecological restoration goals. Copyright © 2015 Elsevier B.V. All rights reserved.

Understanding and simulating vibrations of plain bridge cables under varying meteorological conditions

DEFF Research Database (Denmark)

Matteoni, Giulia

amplitude peak to peak amplitudes, occurred. This latter behaviour was likely to be associated to dry inclined galloping. Passive dynamic wind tunnel tests were finally undertaken in presence of rain, using the same cable model as adopted in the dry state. The tests served to improve the current......The dissertation investigates the phenomenon of wind induced vibration of bridge cables under varying meteorological conditions. A twin research approach is adopted, where wind tunnel investigation of full-scale bridge cable section models is paralleled with theoretical modelling. A literature......-scale monitoring, wind tunnel testing and theoretical modelling. An extensive wind tunnel test campaign was then undertaken in order to further understand the onset conditions and characteristics of instability in the different climatic conditions described in the literature. Tests were separated into two...

An in vitro experimental study of flow past aortic valve under varied pulsatile conditions

Science.gov (United States)

Zhang, Ruihang; Zhang, Yan

2017-11-01

Flow past aortic valve represents a complex fluid-structure interaction phenomenon that involves pulsatile, vortical, and turbulent conditions. The flow characteristics immediately downstream of the valve, such as the variation of pulsatile flow velocity, formation of vortices, distribution of shear stresses, are of particular interest to further elucidate the role of hemodynamics in various aortic diseases. However, the fluid dynamics of a realistic aortic valve is not fully understood. Particularly, it is unclear how the flow fields downstream of the aortic valve would change under varied pulsatile inlet boundary conditions. In this study, an in vitro experiment has been conducted to investigate the flow fields downstream of a silicone aortic valve model within a cardiovascular flow simulator. Phased-locked Particle Image Velocimetry measurements were performed to map the velocity fields and Reynolds normal and shear stresses at different phases in a cardiac cycle. Temporal variations of pressure across the valve model were measured using high frequency transducers. Results have been compared for different pulsatile inlet conditions, including varied frequencies (heart rates), magnitudes (stroke volumes), and cardiac contractile functions (shapes of waveforms).

A SVDD and K-Means Based Early Warning Method for Dual-Rotor Equipment under Time-Varying Operating Conditions

Directory of Open Access Journals (Sweden)

Zhinong Jiang

2018-01-01

Full Text Available Under frequently time-varying operating conditions, equipment with dual rotors like gas turbines is influenced by two rotors with different rotating speeds. Alarm methods of fixed threshold are unable to consider the influences of time-varying operating conditions. Hence, those methods are not suitable for monitoring dual-rotor equipment. An early warning method for dual-rotor equipment under time-varying operating conditions is proposed in this paper. The influences of time-varying rotating speeds of dual rotors on alarm thresholds have been considered. Firstly, the operating conditions are divided into several limited intervals according to rotating speeds of dual rotors. Secondly, the train data within each interval is processed by SVDD and the allowable ranges (i.e., the alarm threshold of the vibration are determined. The alarm threshold of each interval of operating conditions is obtained. The alarm threshold can be expressed as a sphere, whose controlling parameters are the coordinate of the center and the radius. Then, the cluster center of the test data, whose alarm state is to be judged, can be extracted through K-means. Finally, the alarm state can be obtained by comparing the cluster center with the corresponding sphere. Experiments are conducted to validate the proposed method.

Conditions associated with Clostridium sporogenes growth as a surrogate for Clostridium botulinum in nonthermally processed canned butter.

Science.gov (United States)

Taylor, R H; Dunn, M L; Ogden, L V; Jefferies, L K; Eggett, D L; Steele, F M

2013-05-01

The objective of this study was to better understand the effect of butter composition and emulsion structure on growth and survival of Clostridium sporogenes, used as a surrogate for C. botulinum in canned butter. The lack of a thermal process step in commercially available canned butter raises questions of potential safety, because it is hermetically sealed and generally exhibits anaerobic growth conditions, which are optimal for Clostridium botulinum growth. Without thermal processing, low-acid canned foods must have inhibitory factors present to prevent C. botulinum growth. Some potential intrinsic inhibitory factors, or hurdles, within butter include: reduced water activity, acidity in cultured products, elevated salt content, and the micro-droplet nature of the aqueous phase in the butter emulsion. It was hypothesized that a normal, intact butter emulsion would have sufficient hurdles to prevent C. botulinum growth, whereas a broken butter emulsion would result in a coalesced aqueous phase that would allow for C. botulinum growth. Batch-churned butter was inoculated with C. sporogenes; butter samples with varying salt contents (0, 0.8, 1.6, and 2.4% wt/wt NaCl) were prepared and stored in coated steel cans for varying times (1 or 2 wk) and temperatures (22 or 41°C) to determine temperature and emulsion structure effects on C. sporogenes growth. Samples stored at 41°C showed a significant increase in C. sporogenes growth compared with those stored at 22°C. Furthermore, NaCl addition was found to have a significant effect on C. sporogenes growth, with 0.8% NaCl promoting more growth than 0%, but with decreases in growth observed at 1.6 and 2.4%. Uninoculated control plates were also found to have bacterial growth; this growth was attributed to other anaerobic bacteria present within the cream. It was concluded that removal of the hurdle created by the micro-droplet size of the emulsion aqueous phase could result in C. botulinum growth even at elevated salt

Theory of electromagnetic cyclotron wave growth in a time-varying magnetoplasma

International Nuclear Information System (INIS)

Gail, W.B.

1990-01-01

The time-dependent growth rate for parallel propagating electromagnetic cyclotron waves is derived for a magnetoplasma which is characterized by a time dependent compressional perturbation superimposed on an equilibrium configuration. Such perturbations are commonly observed in the Earth's magnetosphere as a consequence of resonant field line oscillations, solar-wind disturbances, and other phenomena. The time dependencies of the magnetic field, thermal plasma density, energetic particle distribution function, and resonance condition are first related through a single dimensionless time parameter b(t) using the ideal MHD assumption. For cases in which the particle distribution can be described by F(α, E) = f(E)sin a(E) α, the time dependent wave growth rate is then given by γ≅ γ 0 (1 + Λ) where γ 0 is the equilibrium growth rate and Λ(b) is a function of the equilibrium parameters and the time parameter b. The term |Λ| is generally small compared to 1, and the effect is a small modulation of the equilibrium growth rate by Λ. If the particle distribution is locally near marginal stability, however, |Λ| is large compared to 1, and the growth rate modulation can be much larger than for a distribution which is not near marginal stability. The results suggest that particle populations which are near marginal stability may be strongly influenced by perturbations in the magnetic field and plasma. Marginally stable distributions may thus play an important role in magnetospheric dynamics as well as determination of radiation belt characteristics

Effect of environmental and cultural conditions on medium pH and explant growth performance of Douglas-fir ( Pseudotsuga menziesii) shoot cultures

OpenAIRE

Chen, Chien-Chih; Bates, Rick; Carlson, John

2015-01-01

The medium pH level of plant tissue cultures has been shown to be essential to many aspects of explant development and growth. Sensitivity or tolerance of medium pH change in vitro varies according to specific requirements of individual species. The objectives of this study are to 1) determine medium pH change over time in storage conditions and with presence of explants, 2) evaluate the effects of medium pH change on explant growth performance and 3) assess the effects of adding a pH stabili...

Growth of verbal short-term memory of nonwords varying in phonotactic probability : A longitudinal study with monolingual and bilingual children

NARCIS (Netherlands)

Messer, Marielle H.|info:eu-repo/dai/nl/304835226; Verhagen, Josje|info:eu-repo/dai/nl/277955882; Boom, Jan|info:eu-repo/dai/nl/07472732X; Mayo, Aziza Y.|info:eu-repo/dai/nl/271313404; Leseman, Paul P M|info:eu-repo/dai/nl/070760810

2015-01-01

This study investigates the hypothesis that verbal short-term memory growth in young children can be explained by increases in long-term linguistic knowledge. To this aim, we compare children's recall of nonwords varying in phonotactic probability. If our assumption holds, there should be growth in

Effect of growth conditions on microbial activity and iron-sulfide production by Desulfovibrio vulgaris

International Nuclear Information System (INIS)

Zhou, Chen; Vannela, Raveender; Hayes, Kim F.; Rittmann, Bruce E.

2014-01-01

Highlights: • Extended incubation time to 16 days allowed significant FeS crystallization. • A weakly acidic pH greatly enhanced particle growth of mackinawite. • Microbial metabolism of different donors systematically altered the ambient pH. • Greater sulfide accumulation stimulated mackinawite transformation to greigite. - Abstract: Sulfate-reducing bacteria (SRB) can produce iron sulfide (FeS) solids with mineralogical characteristics that may be beneficial for a variety of biogeochemical applications, such as long-term immobilization of uranium. In this study, the growth and metabolism of Desulfovibrio vulgaris, one of the best-studied SRB species, were comprehensively monitored in batch studies, and the biogenic FeS solids were characterized by X-ray diffraction. Controlling the pH by varying the initial pH, the iron-to-sulfate ratio, or the electron donor – affected the growth of D. vulgaris and strongly influenced the formation and growth of FeS solids. In particular, lower pH (from initial conditions or a decrease caused by less sulfate reduction, FeS precipitation, or using pyruvate as the electron donor) produced larger-sized mackinawite (Fe 1+x S). Greater accumulation of free sulfide, from more sulfate reduction by D. vulgaris, also led to larger-sized mackinawite and particularly stimulated mackinawite transformation to greigite (Fe 3 S 4 ) when the free sulfide concentration was 29.3 mM. Furthermore, sufficient free Fe 2+ led to the additional formation of vivianite [Fe 3 (PO 4 ) 2 ·8(H 2 O)]. Thus, microbially relevant conditions (initial pH, choice of electron donor, and excess or deficiency of sulfide) are tools to generate biogenic FeS solids of different characteristics

The growth benefits of aggressive behavior vary with individual metabolism and resource predictability

NARCIS (Netherlands)

Hoogenboom, Mia O.; Armstrong, John D.; Groothuis, Ton G. G.; Metcalfe, Neil B.

2013-01-01

Differences in behavioral responses to environmental conditions and biological interactions are a key determinant of individual performance. This study investigated how the availability and predictability of food resources modulates the growth of animals that adopt different behavioral strategies.

Crack growth threshold under hold time conditions in DA Inconel 718 – A transition in the crack growth mechanism

Directory of Open Access Journals (Sweden)

E. Fessler

2016-01-01

Full Text Available Aeroengine manufacturers have to demonstrate that critical components such as turbine disks, made of DA Inconel 718, meet the certification requirements in term of fatigue crack growth. In order to be more representative of the in service loading conditions, crack growth under hold time conditions is studied. Modelling crack growth under these conditions is challenging due to the combined effect of fatigue, creep and environment. Under these conditions, established models are often conservative but the degree of conservatism can be reduced by introducing the crack growth threshold in models. Here, the emphasis is laid on the characterization of crack growth rates in the low ΔK regime under hold time conditions and in particular, on the involved crack growth mechanism. Crack growth tests were carried out at high temperature (550 °C to 650 °C under hold time conditions (up to 1200 s in the low ΔK regime using a K-decreasing procedure. Scanning electron microscopy was used to identify the fracture mode involved in the low ΔK regime. EBSD analyses and BSE imaging were also carried out along the crack path for a more accurate identification of the fracture mode. A transition from intergranular to transgranular fracture was evidenced in the low ΔK regime and slip bands have also been observed at the tip of an arrested crack at low ΔK. Transgranular fracture and slip bands are usually observed under pure fatigue loading conditions. At low ΔK, hold time cycles are believed to act as equivalent pure fatigue cycles. This change in the crack growth mechanism under hold time conditions at low ΔK is discussed regarding results related to intergranular crack tip oxidation and its effect on the crack growth behaviour of Inconel 718 alloy. A concept based on an “effective oxygen partial pressure” at the crack tip is proposed to explain the transition from transgranular to intergranular fracture in the low ΔK regime.

Globally exponential stability condition of a class of neural networks with time-varying delays

International Nuclear Information System (INIS)

Liao, T.-L.; Yan, J.-J.; Cheng, C.-J.; Hwang, C.-C.

2005-01-01

In this Letter, the globally exponential stability for a class of neural networks including Hopfield neural networks and cellular neural networks with time-varying delays is investigated. Based on the Lyapunov stability method, a novel and less conservative exponential stability condition is derived. The condition is delay-dependent and easily applied only by checking the Hamiltonian matrix with no eigenvalues on the imaginary axis instead of directly solving an algebraic Riccati equation. Furthermore, the exponential stability degree is more easily assigned than those reported in the literature. Some examples are given to demonstrate validity and excellence of the presented stability condition herein

Technical conditions for sustainable growth in economic theory. An analysis

International Nuclear Information System (INIS)

Granda C, Catalina

2008-01-01

Economic theory and its models point out returns to scale, substitution among productive factors and technological progress as conditions for sustainable growth. This work aims at a critical appraisal of these conditions, particularly the ones related to substitution between natural resources and manmade capital and technical change, by recognizing the inevitable physical scarcity of resources concomitant to the human actions in a world governed by hemodynamic restrictions. To do so, the role that the mentioned conditions play in the theories of economic growth with resources is analyzed, and its limitations and objections from a biophysical perspective are indicated as well. Finally, a brief consideration as to how inappropriate the theoretical representations of economic activities are to take account of growth in spite of resource exhaustion or degradation is carried out

Effect of the growth conditions on the anisotropy, domain structures and the relaxation in Co thin films

Energy Technology Data Exchange (ETDEWEB)

Mallik, Srijani; Mallick, Sougata; Bedanta, Subhankar, E-mail: sbedanta@niser.ac.in

2017-04-15

We report a systematic study on the anisotropy symmetry, magnetic domains and magnetic relaxation behavior in Co thin films deposited on MgO (001) substrate by varying (i) the pre-annealing condition and (ii) the speed of substrate rotation during deposition. Substrate annealing prior to deposition leads to the formation of textured thin films. On contrary Co films prepared without substrate pre-annealing exhibit polycrystalline nature. Surface topography imaged by atomic force microscopy (AFM) depicts a profound effect of growth condition on grain size and its distribution. Magnetic hysteresis measurement along with simultaneous domain imaging has been performed by magneto optic Kerr effect (MOKE) based microscope by varying the angle (ϕ) between the easy axis and the direction of applied magnetic field. We observed the existence of cubic and uniaxial anisotropy due to the presence of substrate annealing and oblique angular deposition, respectively. Along the easy axis, magnetization reversal is governed by 180° domain wall motion via branched domains. However, for easy axis<ϕgrowth of Co on MgO(001) substrate. • The structure has clear implication on the magnetic properties. • The magnetic relaxation has been studied for both textured and polycrystalline films.

The list of strains and growth conditions - The Rice Growth Monitoring for The Phenotypic Functional Analysis | LSDB Archive [Life Science Database Archive metadata

Lifescience Database Archive (English)

Full Text Available List Contact us The Rice Growth Monitoring for The Phenotypic Functional Analysis The list of strains and growth... conditions Data detail Data name The list of strains and growth conditions DOI 10.18908/lsdba.nbdc00945...-001 Description of data contents The list of strains and growth conditions for respective samples. Data fil...servation Intervals of imaging Intervals of imaging Growth data Graph of chronological changes in growth Ima...History of This Database Site Policy | Contact Us The list of strains and growth conditions - The Rice Growth Monitoring for The Phenotypic Functional Analysis | LSDB Archive ...

Crack growth under combined creep and fatigue conditions in alloy 800

International Nuclear Information System (INIS)

Pfaffelhuber, M.; Roedig, M.; Schubert, F.; Nickel, H.

1989-08-01

To investigate the crack growth behaviour under combined creep-fatigue loading, CT 25 mm-specimens of X10NiCrAlTi 32 20 (Alloy 800) have been tested in experiments with cyclic loadings and hold times, with static loadings and short stress rekief interrupts, with ramp type loadings and with sequences of separate fatigue and creep crack growth periods. The test temperature of 700deg C was selected because only in this temperature range this alloy provides similar amounts of crack growth under creep and fatigue conditions due to equivalent stress levels. For the estimation of crack growth under combined loading conditions a linear accumulation of increase in crack length was proved using the crack growth laws of pure creep and fatigue crack growth. Hold time and ramp loadings lead to a higher crack growth rate compared with pure creep or pure fatigue crack growth tests. In hold time experiments the crack growth rate is higher than ramp tests of the same period time. The results of hold time tests can be fairly enough predicted by linear damage accumulation rules. (orig.) [de

Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks

Science.gov (United States)

Zaal, Peter M. T.; Sweet, Barbara T.

2012-01-01

Recent developments in fly-by-wire control architectures for rotorcraft have introduced new interest in the identification of time-varying pilot control behavior in multi-axis control tasks. In this paper a maximum likelihood estimation method is used to estimate the parameters of a pilot model with time-dependent sigmoid functions to characterize time-varying human control behavior. An experiment was performed by 9 general aviation pilots who had to perform a simultaneous roll and pitch control task with time-varying aircraft dynamics. In 8 different conditions, the axis containing the time-varying dynamics and the growth factor of the dynamics were varied, allowing for an analysis of the performance of the estimation method when estimating time-dependent parameter functions. In addition, a detailed analysis of pilots adaptation to the time-varying aircraft dynamics in both the roll and pitch axes could be performed. Pilot control behavior in both axes was significantly affected by the time-varying aircraft dynamics in roll and pitch, and by the growth factor. The main effect was found in the axis that contained the time-varying dynamics. However, pilot control behavior also changed over time in the axis not containing the time-varying aircraft dynamics. This indicates that some cross coupling exists in the perception and control processes between the roll and pitch axes.

Bacillus spp. from rainforest soil promote plant growth under limited nitrogen conditions.

Science.gov (United States)

Huang, X-F; Zhou, D; Guo, J; Manter, D K; Reardon, K F; Vivanco, J M

2015-03-01

The aim of this study was to evaluate effects of PGPR (plant growth-promoting rhizobacteria) isolated from rainforest soil on different plants under limited nitrogen conditions. Bacterial isolates from a Peruvian rainforest soil were screened for plant growth-promoting effects on Arabidopsis (Col-0). Four selected isolates including one Bacillus subtilis, two B. atrophaeus and one B. pumilus significantly promoted growth of Zea mays L. and Solanum lycopersicum under greenhouse conditions. Moreover, the PGPRs significantly promoted growth of S. lycopersicum in both low and nitrogen-amended soil conditions. These PGPR strains were further studied to obtain insights into possible mechanisms of plant growth promotion. Volatile chemicals from those isolates promoted Arabidopsis growth, and the expression of genes related to IAA production was induced in the Arabidopsis plants treated with PGPRs. Further, selected PGPR strains triggered induced systemic resistance (ISR) against Pseudomonas syringae pv tomato DC3000 in Arabidopsis. PGPR strains isolated from the rainforest soil promoted the plant growth of Arabidopsis, corn and tomato. New PGPR that have wider adaptability to different crops, soils and environmental conditions are needed to decrease our reliance on agricultural amendments derived from fossil-based fuels. The PGPRs isolated from a nonagricultural site constitute new plant growth-promoting strains that could be developed for agricultural uses. © 2014 The Society for Applied Microbiology.

Texture of the nano-crystalline AlN thin films and the growth conditions in DC magnetron sputtering

Directory of Open Access Journals (Sweden)

Shakil Khan

2015-08-01

Full Text Available DC reactive magnetron sputtering technique has been used for the preparation of AlN thin films. The deposition temperature and the flow ratio of N2/Ar were varied and subsequent dependency of the films crystallites orientation/texture has been addressed. In general, deposited films were found hexagonal polycrystalline with a (002 preferred orientation. The X-ray diffraction (XRD data revealed that the film crystallinity improves, with the increase of substrate temperature from 300 °C to 500 °C. The dropped in full width half maximum (FWHM of the XRD rocking curve value further confirmed it. However, increasing substrate temperature above 500 °C or reducing the nitrogen condition (from 60 to 30% in the environment induced the growth of crystallites with (102 and (103 orientations. The rise of rocking curve FWHM for the corresponding conditions depicted that the films texture quality deteriorated. A further confirmation of the variation in film texture/orentation with the growth conditions has been obtained from the variation in FWHM values of a dominant E1 (TO mode in the Fourier transform infrared (FTIR spectra and the E2 (high mode in Raman spectra. We have correlated the columnar structure in AFM surface analyses with the (002 or c-axis orientation as well. Spectroscopic ellipsometry of the samples have shown a higher refractive index at 500 °C growth temperature.

Robust metabolic responses to varied carbon sources in natural and laboratory strains of Saccharomyces cerevisiae.

Directory of Open Access Journals (Sweden)

Wayne A Van Voorhies

Full Text Available Understanding factors that regulate the metabolism and growth of an organism is of fundamental biologic interest. This study compared the influence of two different carbon substrates, dextrose and galactose, on the metabolic and growth rates of the yeast Saccharomyces cerevisiae. Yeast metabolic and growth rates varied widely depending on the metabolic substrate supplied. The metabolic and growth rates of a yeast strain maintained under long-term laboratory conditions was compared to strain isolated from natural condition when grown on different substrates. Previous studies had determined that there are numerous genetic differences between these two strains. However, the overall metabolic and growth rates of a wild isolate of yeast was very similar to that of a strain that had been maintained under laboratory conditions for many decades. This indicates that, at in least this case, metabolism and growth appear to be well buffered against genetic differences. Metabolic rate and cell number did not co-vary in a simple linear manner. When grown in either dextrose or galactose, both strains showed a growth pattern in which the number of cells continued to increase well after the metabolic rate began a sharp decline. Previous studied have reported that O₂ consumption in S. cerevisiae grown in reduced dextrose levels were elevated compared to higher levels. Low dextrose levels have been proposed to induce caloric restriction and increase life span in yeast. However, there was no evidence that reduced levels of dextrose increased metabolic rates, measured by either O₂ consumption or CO₂ production, in the strains used in this study.

Improving Delay-Range-Dependent Stability Condition for Systems with Interval Time-Varying Delay

Directory of Open Access Journals (Sweden)

Wei Qian

2013-01-01

Full Text Available This paper discusses the delay-range-dependent stability for systems with interval time-varying delay. Through defining the new Lyapunov-Krasovskii functional and estimating the derivative of the LKF by introducing new vectors, using free matrices and reciprocally convex approach, the new delay-range-dependent stability conditions are obtained. Two well-known examples are given to illustrate the less conservatism of the proposed theoretical results.

Analysis of gene essentiality in Escherichia coli across strains and growth conditions

DEFF Research Database (Denmark)

Bonde, Ida; Lennen, Rebecca; Cardoso, Joao

are either essential or detrimental for growth in the test condition in question. In this study the TN-Seq method was used to investigate the differences in gene essentiality between four laboratory strains of E.coli subjected to four different growth conditions to investigate the reason for the differences...

Fourth-quarter Economic Growth and Time-varying Expected Returns

DEFF Research Database (Denmark)

Møller, Stig V.; Rangvid, Jesper

not predict returns. Fourth-quarter economic growth rates contain considerably more information about expected returns than standard variables used in the literature, are robust to the choice of macro variable, and work in-sample, out-of-sample, and in subsamples. To help explain these results, we show...... that economic growth and growth in consumer confidence are correlated during the fourth quarter, but not during the other quarters: When economic growth is low during the fourth quarter, confidence in the economy is also low such that investors require higher future returns. We discuss rational and behavioral...... reasons why fourth-quarter economic growth, growth in consumer confidence, and expected returns are related....

Diffusive growth of a single droplet with three different boundary conditions

Science.gov (United States)

Tavassoli, Z.; Rodgers, G. J.

2000-02-01

We study a single, motionless three-dimensional droplet growing by adsorption of diffusing monomers on a 2D substrate. The diffusing monomers are adsorbed at the aggregate perimeter of the droplet with different boundary conditions. Models with both an adsorption boundary condition and a radiation boundary condition, as well as a phenomenological model, are considered and solved in a quasistatic approximation. The latter two models allow particle detachment. In the short time limit, the droplet radius grows as a power of the time with exponents of 1/4, 1/2 and 3/4 for the models with adsorption, radiation and phenomenological boundary conditions, respectively. In the long time limit a universal growth rate as $[t/\\ln(t)]^{1/3}$ is observed for the radius of the droplet for all models independent of the boundary conditions. This asymptotic behaviour was obtained by Krapivsky \\cite{krapquasi} where a similarity variable approach was used to treat the growth of a droplet with an adsorption boundary condition based on a quasistatic approximation. Another boundary condition with a constant flux of monomers at the aggregate perimeter is also examined. The results exhibit a power law growth rate with an exponent of 1/3 for all times.

Assessment of a surface-layer parameterization scheme in an atmospheric model for varying meteorological conditions

Directory of Open Access Journals (Sweden)

T. J. Anurose

2014-06-01

Full Text Available The performance of a surface-layer parameterization scheme in a high-resolution regional model (HRM is carried out by comparing the model-simulated sensible heat flux (H with the concurrent in situ measurements recorded at Thiruvananthapuram (8.5° N, 76.9° E, a coastal station in India. With a view to examining the role of atmospheric stability in conjunction with the roughness lengths in the determination of heat exchange coefficient (CH and H for varying meteorological conditions, the model simulations are repeated by assigning different values to the ratio of momentum and thermal roughness lengths (i.e. z0m/z0h in three distinct configurations of the surface-layer scheme designed for the present study. These three configurations resulted in differential behaviour for the varying meteorological conditions, which is attributed to the sensitivity of CH to the bulk Richardson number (RiB under extremely unstable, near-neutral and stable stratification of the atmosphere.

Mortality and morbidity risks vary with birth weight standard deviation score in growth restricted extremely preterm infants.

Science.gov (United States)

Yamakawa, Takuji; Itabashi, Kazuo; Kusuda, Satoshi

2016-01-01

To assess whether the mortality and morbidity risks vary with birth weight standard deviation score (BWSDS) in growth restricted extremely preterm infants. This was a multicenter retrospective cohort study using the database of the Neonatal Research Network of Japan and including 9149 infants born between 2003 and 2010 at <28 weeks gestation. According to the BWSDSs, the infants were classified as: <-2.0, -2.0 to -1.5, -1.5 to -1.0, -1.0 to -0.5, and ≥-0.5. Infants with BWSDS≥-0.5 were defined as non-growth restricted group. After adjusting for covariates, the risks of mortality and some morbidities were different among the BWSDS groups. Compared with non-growth restricted group, the adjusted odds ratio (aOR) for mortality [aOR, 1.69; 95% confidence interval (CI), 1.35-2.12] and chronic lung disease (CLD) (aOR, 1.28; 95% CI, 1.07-1.54) were higher among the infants with BWSDS -1.5 to <-1.0. The aOR for severe retinopathy of prematurity (ROP) (aOR, 1.36; 95% CI, 1.09-1.71) and sepsis (aOR, 1.72; 95% CI, 1.32-2.24) were higher among the infants with BWSDS -2.0 to <-1.5. The aOR for necrotizing enterocolitis (NEC) (aOR, 2.41; 95% CI, 1.64-3.55) was increased at a BWSDS<-2.0. Being growth restricted extremely preterm infants confer additional risks for mortality and morbidities such as CLD, ROP, sepsis and NEC, and these risks may vary with BWSDS. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Consumption growth and time-varying expected stock returns

DEFF Research Database (Denmark)

Vinther Møller, Stig

2008-01-01

When the consumption growth rate is measured based upon fourth quarter data, it tracks predictable variation in future excess stock returns. Low fourth quarter consumption growth rates predict high future excess stock returns such that expected returns are high at business cycle troughs and low...... of each calendar year, and at possibly random times in between. The consumption growth rate measured based upon fourth quarter data is a much stronger predictive variable than benchmark predictive variables such as the dividend-price ratio, the term spread, and the default spread....

Controls of growth phenology vary in seedlings of three, co-occurring ecologically distinct northern conifers.

Science.gov (United States)

Green, D Scott

2007-08-01

The objective of this study was to investigate the effects of temperature and seed-source elevation on height-growth phenology of three co-occurring and ecologically distinct northern conifers (Pinus contorta Dougl. ex Loud. var. latifolia (lodgepole pine), Picea glauca (Moench) Voss x Picea engelmannii Parry ex Engelm. (interior spruce) and Abies lasiocarpa (Hook.) Nutt. (subalpine fir)). Seed from populations of the three indigenous and co-occurring species was collected across an elevational transect on the southwestern slope of McBride Peak, near Prince George, BC. Collection sites were at elevations of 750 to 1850 m, the latter being close to the tree line. In 2003, seeds were germinated and seedlings raised under favorable growing conditions in a temperature-controlled glasshouse. In 2004, seedlings of each population were grown in natural daylengths at a location within 50 km of the seed collection site both in a temperature-controlled glasshouse and at a nearby field site, and height growth was recorded twice a week throughout the growing season. Species differed in both the date and the accumulated heat sum above 5 degrees C for the initiation and cessation of shoot extension. Growth durations (which integrate growth initiation and growth cessation) were more similar among species in the field than in the glasshouse. This suggests that different mechanisms of phenological control among co-occurring species can result in adaptive "equivalence" under a particular set of climatic conditions.

Selective area growth of GaN rod structures by MOVPE: Dependence on growth conditions

Energy Technology Data Exchange (ETDEWEB)

Li, Shunfeng; Fuendling, Soenke; Wang, Xue; Erenburg, Milena; Al-Suleiman, Mohamed Aid Mansur; Wei, Jiandong; Wehmann, Hergo-Heinrich; Waag, Andreas [Institut fuer Halbleitertechnik, TU Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Bergbauer, Werner [Institut fuer Halbleitertechnik, TU Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany); Osram Opto Semiconductors GmbH, Leibnizstr. 4, 93055 Regensburg (Germany); Strassburg, Martin [Osram Opto Semiconductors GmbH, Leibnizstr. 4, 93055 Regensburg (Germany)

2011-07-15

Selective area growth of GaN nanorods by metalorganic vapor phase epitaxy is highly demanding for novel applications in nano-optoelectronic and nanophotonics. Recently, we report the successful selective area growth of GaN nanorods in a continuous-flow mode. In this work, as examples, we show the morphology dependence of GaN rods with {mu}m or sub-{mu}m in diameters on growth conditions. Firstly, we found that the nitridation time is critical for the growth, with an optimum from 90 to 180 seconds. This leads to more homogeneous N-polar GaN rods growth. A higher temperature during GaN rod growth tends to increase the aspect ratio of the GaN rods. This is due to the enhanced surface diffusion of growth species. The V/III ratio is also an important parameter for the GaN rod growth. Its increase causes reduction of the aspect ratio of GaN rods, which could be explained by the relatively lower growth rate on (000-1) N-polar top surface than it on {l_brace}1-100{r_brace} m-planes by supplying more NH{sub 3} (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Estimation of thermal sensation during varied air temperature conditions.

Science.gov (United States)

Katsuura, T; Tabuchi, R; Iwanaga, K; Harada, H; Kikuchi, Y

1998-03-01

Seven male students were exposed to four varied air temperature environments: hot (37 degrees C) to neutral (27 degrees C) (HN), neutral to hot (NH), cool (17 degrees C) to neutral (CN), and neutral to cool (NC). The air temperature was maintained at the first condition for 20 min, then was changed to the second condition after 15 min and was held there for 20 min. Each subject wore a T-shirt, briefs, trunks, and socks. Each sat on a chair and was continuously evaluated for thermal sensation, thermal comfort, and air velocity sensation. Some physiological and thermal parameters were also measured every 5 s during the experiment. The correlation between thermal sensation and skin temperature at 15 sites was found to be poor. The subjects felt much warmer during the rising phase of the air temperature (CN, NH) than during the descending phase (HN, NC) at a given mean skin temperature. However, thermal sensation at the same heat flux or at the same value of the difference between skin and air temperature (delta(Tsk - Ta)) was not so different among the four experimental conditions, and the correlation between thermal sensation and heat flux or delta(Tsk - Ta) was fairly good. The multiple regression equation of the thermal sensation (TS) on 15 sites of skin temperature (Tsk; degrees C) was calculated and the coefficient of determination (R*2) was found to be 0.656. Higher coefficients of determination were found in the equations of thermal sensation for the heat flux (H; kcal.m-2.h-1) at the right and left thighs of the subjects and on delta(Tsk - Ta) (degrees C) at 4 sites. They were as follows: TS = 2.04 - 0.016 Hright - 0.036 Hleft; R*2 = 0.717, TS = 1.649 + 0.013 delta(Tsk - Ta)UpperArm - 0.036 delta(Tsk - Ta)Chest - 0.223 delta(Tsk - Ta)Thigh-0.083 delta(Tsk - Ta)LowerLeg; R*2 = 0.752, respectively.

Optimization of growth medium and fermentation conditions for ...

African Journals Online (AJOL)

A sequential optimization approach based on statistical experimental designs was employed to optimize growth medium and fermentation conditions, in order to improve the antibiotic activity of Xenorhabdus nematophila TB. Tryptone soyptone broth (TSB) was chosen as the original medium for optimization. Glucose and ...

Rimsulfuron in Soil: Effects on Microbiological Properties under Varying Soil Conditions

Directory of Open Access Journals (Sweden)

Ljiljana Radivojević

2011-01-01

Full Text Available The effects of rimsulfuron a sulfonylurea herbicide on the growth and activity of soil microorganisms under laboratory conditions was investigated in two soils. The application rates were: 0.2, 2.0 and 20.0 mg a.i kg-1 soil. The lowest concentration tested was the label rate (0.2 mg a.i kg-1, and the other two were ten and hundred timeshigher. No adverse effects on microbiological processes were observed for the label rate. Decrease in microbial biomass carbon, dehydrogenase activity, fungi and bacteria in comparison with untreated control, were found at higher rates. The magnitude of these effects were generally slight and transitory.

Glucose metabolism in Lactococcus lactis MG1363 under different aeration conditions: Requirement of acetate to sustain growth under microaerobic conditions

DEFF Research Database (Denmark)

Nordkvist, Mikkel; Jensen, N.B.S.; Villadsen, John

2003-01-01

Lactococcus lactis subsp. lactis MG1363 was grown in batch cultures on a defined medium with glucose as the energy source under different aeration conditions, namely, anaerobic conditions, aerobic conditions, and microaerobic conditions with a dissolved oxygen tension of 5% (when saturation...... resulted in acetate, CO2, and acetoin replacing formate and ethanol as end products. Under microaerobic conditions, growth came to a gradual halt, although more than 60% of the glucose was still left. A decline in growth was not observed during microaerobic cultivation when acetate was added to the medium...

An endogenous Taylor condition in an endogenous growth monetary policy model

OpenAIRE

Le, Mai Vo; Gillman, Max; Minford, Patrick

2007-01-01

The paper derives a Taylor condition as part of the agent's equilibrium behavior in an endogenous growth monetary economy. It shows the assumptions necessary to make it almost identical to the original Taylor rule, and that it can interchangably take a money supply growth rate form. From the money supply form, simple policy experiments are conducted. A full central bank policy model is derived that includes the Taylor condition along with equations comparable to the standard aggregate-demand/...

High throughput nanostructure-initiator mass spectrometry screening of microbial growth conditions for maximal β-glucosidase production.

Science.gov (United States)

Cheng, Xiaoliang; Hiras, Jennifer; Deng, Kai; Bowen, Benjamin; Simmons, Blake A; Adams, Paul D; Singer, Steven W; Northen, Trent R

2013-01-01

Production of biofuels via enzymatic hydrolysis of complex plant polysaccharides is a subject of intense global interest. Microbial communities are known to express a wide range of enzymes necessary for the saccharification of lignocellulosic feedstocks and serve as a powerful reservoir for enzyme discovery. However, the growth temperature and conditions that yield high cellulase activity vary widely, and the throughput to identify optimal conditions has been limited by the slow handling and conventional analysis. A rapid method that uses small volumes of isolate culture to resolve specific enzyme activity is needed. In this work, a high throughput nanostructure-initiator mass spectrometry (NIMS)-based approach was developed for screening a thermophilic cellulolytic actinomycete, Thermobispora bispora, for β-glucosidase production under various growth conditions. Media that produced high β-glucosidase activity were found to be I/S + glucose or microcrystalline cellulose (MCC), Medium 84 + rolled oats, and M9TE + MCC at 45°C. Supernatants of cell cultures grown in M9TE + 1% MCC cleaved 2.5 times more substrate at 45°C than at all other temperatures. While T. bispora is reported to grow optimally at 60°C in Medium 84 + rolled oats and M9TE + 1% MCC, approximately 40% more conversion was observed at 45°C. This high throughput NIMS approach may provide an important tool in discovery and characterization of enzymes from environmental microbes for industrial and biofuel applications.

High throughput nanostructure-initiator mass spectrometry screening of microbial growth conditions for maximal β-glucosidase production

Directory of Open Access Journals (Sweden)

Xiaoliang eCheng

2013-12-01

Full Text Available Production of biofuels via enzymatic hydrolysis of complex plant polysaccharides is a subject of intense global interest. Microbial communities are known to express a wide range of enzymes necessary for the saccharification of lignocellulosic feedstocks and serve as a powerful reservoir for enzyme discovery. However, the growth temperature and conditions that yield high cellulase activity vary widely, and the throughput to identify optimal conditions has been limited by the slow handling and conventional analysis. A rapid method that uses small volumes of isolate culture to resolve specific enzyme activity is needed. In this work, a high throughput nanostructure-initiator mass spectrometry (NIMS based approach was developed for screening a thermophilic cellulolytic actinomycete, Thermobispora bispora, for β-glucosidase production under various growth conditions. Media that produced high β-glucosidase activity were found to be I/S + glucose or microcrystalline cellulose (MCC, Medium 84 + rolled oats, and M9TE + MCC at 45 °C. Supernatants of cell cultures grown in M9TE + 1% MCC cleaved 2.5 times more substrate at 45 °C than at all other temperatures. While T. bispora is reported to grow optimally at 60 °C in Medium 84 + rolled oats and M9TE + 1% MCC, approximately 40% more conversion was observed at 45 °C. This high throughput NIMS approach may provide an important tool in discovery and characterization of enzymes from environmental microbes for industrial and biofuel applications.

Soil texture and climatc conditions for biocrust growth limitation: a meta analysis

Science.gov (United States)

Fischer, Thomas; Subbotina, Mariia

2015-04-01

Along with afforestation, attempts have been made to combat desertification by managing soil crusts, and is has been reported that recovery rates of biocrusts are dependent on many factors, including the type, severity, and extent of disturbance; structure of the vascular plant community; conditions of adjoining substrates; availability of inoculation material; and climate during and after disturbance (Belnap & Eldridge 2001). Because biological soil crusts are known to be more stable on and to prefer fine substrates (Belnap 2001), the question arises as to how successful crust management practices can be applied to coarser soil. In previous studies we observed similar crust biomasses on finer soils under arid and on coarser soils under temperate conditions. We hypothesized that the higher water holding capacity of finer substrates would favor crust development, and that the amount of silt and clay in the substrate that is required for enhanced crust development would vary with changes in climatic conditions. In a global meta study, climatic and soil texture threshold values promoting BSC growth were derived. While examining literature sources, it became evident that the amount of studies to be incorporated into this meta analysis was reversely related to the amount of common environmental parameters they share. We selected annual mean precipitaion, mean temperature and the amount of silt and clay as driving variables for crust growth. Response variable was the "relative crust biomass", which was computed per literature source as the ratio between each individual crust biomass value of the given study to the study maximum value reported. We distinguished lichen, green algal, cyanobacterial and moss crusts. To quantify threshold conditions at which crust biomass responded to differences in texture and climate, we (I) determined correlations between bioclimatic variables, (II) calculated linear models to determine the effect of typical climatic variables with soil

Growth and nutrition of baldcypress families planted under varying salinity regimes in Louisiana, USA

Science.gov (United States)

Krauss, K.W.; Chambers, J.L.; Allen, J.A.; Soileau, D.M.; DeBosier, A.S.

2000-01-01

Saltwater intrusion from the Gulf of Mexico is one important factor in the destruction of baldcypress (Taxodium distichum (L.) Rich.) swamps along the Louisiana Gulf Coast, USA. Recent restoration efforts have focused on identification of baldcypress genotypes with greater tolerance to saline conditions than previously reported. To date, salt tolerance investigations have not been conducted under saline field conditions. In 1996, therefore, three plantations were established with 10 half-sib genotype collections of baldcypress in mesohaline wetlands. Tree survival and growth were measured at the end of two growing seasons, and foliar ion concentrations of Na, Cl, K, and Ca and available soil nutrients were measured during the 1996 growing season. In general, soil nutrient concentrations exceeded averages found in other baldcypress stands in the southeastern United States. Seedlings differed among sites in all parameters measured, with height, diameter, foliar biomass, and survival decreasing as site salinity increased. Average seedling height at the end of two years, for example, was 196.4 cm on the lowest salinity site and 121.6 cm on the highest. Several half-sib families maintained greater height growth increments (ranging from 25.5 to 54.5 cm on the highest salinity site), as well as lower foliar ion concentrations of K, Cl, and Ca. Results indicate that genotypic screening of baldcypress may improve growth and vigor of seedlings planted within wetlands impacted by saltwater intrusion.

Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

International Nuclear Information System (INIS)

Tsuji, Hirokazu; Tanabe, Tatsuhiko; Nakajima, Hajime

1994-01-01

A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000 C in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000 to 900 C. The trend observed in the tests from 900 to 1000 C can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900 C plays the role of the protective barrier against the boron dissipation into the environment. (orig.)

Monitoring growth condition of spring maize in Northeast China using a process-based model

Science.gov (United States)

Wang, Peijuan; Zhou, Yuyu; Huo, Zhiguo; Han, Lijuan; Qiu, Jianxiu; Tan, Yanjng; Liu, Dan

2018-04-01

Early and accurate assessment of the growth condition of spring maize, a major crop in China, is important for the national food security. This study used a process-based Remote-Sensing-Photosynthesis-Yield Estimation for Crops (RS-P-YEC) model, driven by satellite-derived leaf area index and ground-based meteorological observations, to simulate net primary productivity (NPP) of spring maize in Northeast China from the first ten-day (FTD) of May to the second ten-day (STD) of August during 2001-2014. The growth condition of spring maize in 2014 in Northeast China was monitored and evaluated spatially and temporally by comparison with 5- and 13-year averages, as well as 2009 and 2013. Results showed that NPP simulated by the RS-P-YEC model, with consideration of multi-scattered radiation inside the crop canopy, could reveal the growth condition of spring maize more reasonably than the Boreal Ecosystem Productivity Simulator. Moreover, NPP outperformed other commonly used vegetation indices (e.g., Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI)) for monitoring and evaluating the growth condition of spring maize. Compared with the 5- and 13-year averages, the growth condition of spring maize in 2014 was worse before the STD of June and after the FTD of August, and it was better from the third ten-day (TTD) of June to the TTD of July across Northeast China. Spatially, regions with slightly worse and worse growth conditions in the STD of August 2014 were concentrated mainly in central Northeast China, and they accounted for about half of the production area of spring maize in Northeast China. This study confirms that NPP is a good indicator for monitoring and evaluating growth condition because of its capacity to reflect the physiological characteristics of crops. Meanwhile, the RS-P-YEC model, driven by remote sensing and ground-based meteorological data, is effective for monitoring crop growth condition over large areas in a near real

Cholera toxin expression by El Tor Vibrio cholerae in shallow culture growth conditions.

Science.gov (United States)

Cobaxin, Mayra; Martínez, Haydee; Ayala, Guadalupe; Holmgren, Jan; Sjöling, Asa; Sánchez, Joaquín

2014-01-01

Vibrio cholerae O1 classical, El Tor and O139 are the primary biotypes that cause epidemic cholera, and they also express cholera toxin (CT). Although classical V. cholerae produces CT in various settings, the El Tor and O139 strains require specific growth conditions for CT induction, such as the so-called AKI conditions, which consist of growth in static conditions followed by growth under aerobic shaking conditions. However, our group has demonstrated that CT production may also take place in shallow static cultures. How these type of cultures induce CT production has been unclear, but we now report that in shallow culture growth conditions, there is virtual depletion of dissolved oxygen after 2.5 h of growth. Concurrently, during the first three to 4 h, endogenous CO2 accumulates in the media and the pH decreases. These findings may explain CT expression at the molecular level because CT production relies on a regulatory cascade, in which the key regulator AphB may be activated by anaerobiosis and by low pH. AphB activation stimulates TcpP synthesis, which induces ToxT production, and ToxT directly stimulates ctxAB expression, which encodes CT. Importantly, ToxT activity is enhanced by bicarbonate. Therefore, we suggest that in shallow cultures, AphB is activated by initial decreases in oxygen and pH, and subsequently, ToxT is activated by intracellular bicarbonate that has been generated from endogenous CO2. This working model would explain CT production in shallow cultures and, possibly, also in other growth conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Varied overstrain injuries of the vertebral column conditioned by evolution

Energy Technology Data Exchange (ETDEWEB)

Kohlbach, W

1983-08-01

During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components.

Varied overstrain injuries of the vertebral column conditioned by evolution

International Nuclear Information System (INIS)

Kohlbach, W.

1983-01-01

During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components. (orig.) [de

Lettuce and rhizosphere microbiome responses to growth promoting Pseudomonas species under field conditions.

Science.gov (United States)

Cipriano, Matheus A P; Lupatini, Manoeli; Lopes-Santos, Lucilene; da Silva, Márcio J; Roesch, Luiz F W; Destéfano, Suzete A L; Freitas, Sueli S; Kuramae, Eiko E

2016-12-01

Plant growth promoting rhizobacteria are well described and recommended for several crops worldwide. However, one of the most common problems in research into them is the difficulty in obtaining reproducible results. Furthermore, few studies have evaluated plant growth promotion and soil microbial community composition resulting from bacterial inoculation under field conditions. Here we evaluated the effect of 54 Pseudomonas strains on lettuce (Lactuca sativa) growth. The 12 most promising strains were phylogenetically and physiologically characterized for plant growth-promoting traits, including phosphate solubilization, hormone production and antagonism to pathogen compounds, and their effect on plant growth under farm field conditions. Additionally, the impact of beneficial strains on the rhizospheric bacterial community was evaluated for inoculated plants. The strains IAC-RBcr4 and IAC-RBru1, with different plant growth promoting traits, improved lettuce plant biomass yields up to 30%. These two strains also impacted rhizosphere bacterial groups including Isosphaera and Pirellula (phylum Planctomycetes) and Acidothermus, Pseudolabrys and Singusphaera (phylum Actinobacteria). This is the first study to demonstrate consistent results for the effects of Pseudomonas strains on lettuce growth promotion for seedlings and plants grown under tropical field conditions. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Effects of enhanced UVB on growth and yield of alfalfa (Medic ago Sativa L.) and soybean (Glycine max L.) under field conditions

International Nuclear Information System (INIS)

Al-Oudat, M.; Baydoun, S.A.; Mohamad, A.

1997-04-01

The effects of 20% increase of UVB on growth and yield of alfalfa (Medicago Sativa L.) and two cultivars of soybean (Glycine Max (L.) Mer) under field conditions have been investigated. The increase of UVB dose ranged between 1.746 and 7.112 J/cm 2 during experiment. The results showed that soybean yield decrease by 16% and 31% in A. 3803 and A. 2522 cultivars respectively, under UVB exposure. The dry weight and leaf area were sensitive in the A. 3803 cultivar, while they were tolerant in the A. 2522 cultivar. Alfalfa response to UVB varied during the different stages of growth, whereas the yield was 12% less in the exposed plants. (author). 21 refs., 17 tabs

Diatom production in the marine environment : implications for larval fish growth and condition

DEFF Research Database (Denmark)

St. John, Michael; Clemmesen, C.; Lund, T.

2001-01-01

To test the effects of diatom production on larval fish growth and condition. laboratory experiments were performed with larval North Sea cod reared on different algal food chains. These food chains were based on cultures of (a) the diatoms Skeletonema costatum and Thalassiosira weissflogii: (b....../omega6 fatty acids in the algal source had no significant effect. The highest and lowest growth rates were observed in food chains based on H. triquetra and T. weissflogii. respectively (means for days 14-16 of 4.0 and - 4.7). The mixed diatom/dinoflagellate diet resulted in inter- mediate growth rates...... and condition. Regressions of growth rates against EPA and DHA content indicated no inhibitory effect of diatom production on growth in larval cod...

Detection and classification of alarm threshold violations in condition monitoring systems working in highly varying operational conditions

Science.gov (United States)

Strączkiewicz, M.; Barszcz, T.; Jabłoński, A.

2015-07-01

All commonly used condition monitoring systems (CMS) enable defining alarm thresholds that enhance efficient surveillance and maintenance of dynamic state of machinery. The thresholds are imposed on the measured values such as vibration-based indicators, temperature, pressure, etc. For complex machinery such as wind turbine (WT) the total number of thresholds might be counted in hundreds multiplied by the number of operational states. All the parameters vary not only due to possible machinery malfunctions, but also due to changes in operating conditions and these changes are typically much stronger than the former ones. Very often, such a behavior may lead to hundreds of false alarms. Therefore, authors propose a novel approach based on parameterized description of the threshold violation. For this purpose the novelty and severity factors are introduced. The first parameter refers to the time of violation occurrence while the second one describes the impact of the indicator-increase to the entire machine. Such approach increases reliability of the CMS by providing the operator with the most useful information of the system events. The idea of the procedure is presented on a simulated data similar to those from a wind turbine.

Detection and classification of alarm threshold violations in condition monitoring systems working in highly varying operational conditions

International Nuclear Information System (INIS)

Strączkiewicz, M; Barszcz, T; Jabłoński, A

2015-01-01

All commonly used condition monitoring systems (CMS) enable defining alarm thresholds that enhance efficient surveillance and maintenance of dynamic state of machinery. The thresholds are imposed on the measured values such as vibration-based indicators, temperature, pressure, etc. For complex machinery such as wind turbine (WT) the total number of thresholds might be counted in hundreds multiplied by the number of operational states. All the parameters vary not only due to possible machinery malfunctions, but also due to changes in operating conditions and these changes are typically much stronger than the former ones. Very often, such a behavior may lead to hundreds of false alarms. Therefore, authors propose a novel approach based on parameterized description of the threshold violation. For this purpose the novelty and severity factors are introduced. The first parameter refers to the time of violation occurrence while the second one describes the impact of the indicator-increase to the entire machine. Such approach increases reliability of the CMS by providing the operator with the most useful information of the system events. The idea of the procedure is presented on a simulated data similar to those from a wind turbine. (paper)

The growth response of plants to elevated CO2 under non-optimal environmental conditions

NARCIS (Netherlands)

Poorter, H.; Pérez-Soba, M.

2001-01-01

Under benign environmental conditions, plant growth is generally stimulated by elevated atmospheric CO2 concentrations. When environmental conditions become sub- or supra-optimal for growth, changes in the biomass enhancement ratio (BER; total plant biomass at elevated CO2 divided by plant biomass

Differences in displayed pump flow compared to measured flow under varying conditions during simulated cardiopulmonary bypass.

LENUS (Irish Health Repository)

Hargrove, M

2008-07-01

Errors in blood flow delivery due to shunting have been reported to reduce flow by, potentially, up to 40-83% during cardiopulmonary bypass. The standard roller-pump measures revolutions per minute and a calibration factor for different tubing sizes calculates and displays flow accordingly. We compared displayed roller-pump flow with ultrasonically measured flow to ascertain if measured flow correlated with the heart-lung pump flow reading. Comparison of flows was measured under varying conditions of pump run duration, temperature, viscosity, varying arterial\\/venous loops, occlusiveness, outlet pressure, use of silicone or polyvinyl chloride (PVC) in the roller race, different tubing diameters, and use of a venous vacuum-drainage device.

Soybean growth responses to enhanced levels of ultraviolet-B radiation under greenhouse conditions

International Nuclear Information System (INIS)

Teramura, A.H.; Sullivan, J.H.

1987-01-01

Soybean (Glycine max [L.] Merr. cv. Essex) was grown in an unshaded greenhouse under three levels of biologically effective ultraviolet-B (UV-BBE) radiation (effective daily dose: 0, 11.5 and 13.6 kJ m -2 ) for 91 days. Plants were harvested at regular intervals beginning 10 days after germination until reproductive maturity. Mathematical growth analysis revealed that the effects of UV-B radiation varied with plant growth stage. The transition period between vegetative and reproductive growth was the most sensitive to UV-B radiation. Intermediate levels of UV-B had deleterious effects on plant height, leaf area, and total plant dry weight at late vegetative and reproductive stages of development. Specific leaf weight increased during vegetative growth but was unaffected by UV-B during reproductive growth stages. Relative growth, net assimilation, and stem elongation rates were decreased by UV-B radiation during vegetative and early reproductive growth stages. Variation in plant responses may be due in part to changes in microclimate within the plant canopy or to differences in repair or protection mechanisms at differing developmental stages. (author)

Varied overstrain injuries of the vertebral column conditioned by evolution

Energy Technology Data Exchange (ETDEWEB)

Kohlbach, W.

1983-08-01

During physiological growth of the juvenile vertebral column, various stages of stability occur which are characterized by the condition of the marginal rim of the vertebral bodies. If the vertebral juvenile column is overstrained, these variations in stability results in a variety of damage to vertebral bodies and vertebral disks. One of these lesions corresponds to Scheuermann's disease (osteochondrosis of vertebral epiphyses in juveniles). Damage of the vertebral column due to overstrain can occur only if the overstrain is applied in upright position. Since Man alone can damage his vertebral column in upright position (as a result of his evolutionary development), Scheuermann's thesis is confirmed that Scheuermann's disease is confined to Man. Spondylolysis/spondylolisthesis is also a damage caused by overstrain. Here, too, the damage can occur only if the load is exercised in upright position, with the exception of a slanted positioning of the intervertebral components.

Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

International Nuclear Information System (INIS)

Tsuji, Hirokazu; Nakajima, Hajime; Tanabe, Tatsuhiko.

1993-09-01

A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000degC in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the born content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000degC to 900degC. The trend observed in the tests from 900degC to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (author)

A novel strategy to identify the critical conditions for growth-induced instabilities.

Science.gov (United States)

Javili, A; Steinmann, P; Kuhl, E

2014-01-01

Geometric instabilities in living structures can be critical for healthy biological function, and abnormal buckling, folding, or wrinkling patterns are often important indicators of disease. Mathematical models typically attribute these instabilities to differential growth, and characterize them using the concept of fictitious configurations. This kinematic approach toward growth-induced instabilities is based on the multiplicative decomposition of the total deformation gradient into a reversible elastic part and an irreversible growth part. While this generic concept is generally accepted and well established today, the critical conditions for the formation of growth-induced instabilities remain elusive and poorly understood. Here we propose a novel strategy for the stability analysis of growing structures motivated by the idea of replacing growth by prestress. Conceptually speaking, we kinematically map the stress-free grown configuration onto a prestressed initial configuration. This allows us to adopt a classical infinitesimal stability analysis to identify critical material parameter ranges beyond which growth-induced instabilities may occur. We illustrate the proposed concept by a series of numerical examples using the finite element method. Understanding the critical conditions for growth-induced instabilities may have immediate applications in plastic and reconstructive surgery, asthma, obstructive sleep apnoea, and brain development. © 2013 Elsevier Ltd. All rights reserved.

Optimizing growth conditions for electroless deposition of Au films ...

Indian Academy of Sciences (India)

Unknown

Optimizing growth conditions for electroless deposition of Au films on. Si(111) substrates. BHUVANA and G U KULKARNI*. Chemistry and Physics of Materials Unit and DST Unit on Nanoscience, Jawaharlal Nehru Centre for. Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India. MS received 24 March 2006.

Comparison of creep behavior under varying load/temperature conditions between Hastelloy XR alloys with different boron content levels

International Nuclear Information System (INIS)

Tsuji, Hirokazu; Nakajima, Hajime; Shindo, Masami; Tanabe, Tatsuhiko; Nakasone, Yuji.

1996-01-01

In the design of the high-temperature components, it is often required to predict the creep rupture life under the conditions in which the stress and/or temperature may vary by using the data obtained with the constant load and temperature creep rupture tests. Some conventional creep damage rules have been proposed to meet the above-mentioned requirement. Currently only limited data are available on the behavior of Hastelloy XR, which is a developed alloy as the structural material for high-temperature components of the High-Temperature Engineering Test Reactor (HTTR), under varying stress and/or temperature creep conditions. Hence a series of constant load and temperature creep rupture tests as well as varying load and temperature creep rupture tests was carried out on two kinds of Hastelloy XR alloys whose boron content levels are different, i.e., below 10 and 60 mass ppm. The life fraction rule completely fails in the prediction of the creep rupture life of Hastelloy XR with 60 mass ppm boron under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR with below 10 mass ppm boron. The change of boron content level of the material during the tests is the most probable source of impairing the applicability of the life fraction rule to Hastelloy XR whose boron content level is 60 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the two stage creep test conditions from 1000 to 900degC. The trend observed in the two stage creep tests from 900 to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (J.P.N.)

Effects of plant–soil feedback on tree seedling growth under arid conditions

NARCIS (Netherlands)

Meijer, S.S.; Holmgren, M.; Van der Putten, W.H.

2011-01-01

Aims Plants are able to influence their growing environment by changing biotic and abiotic soil conditions. These soil conditions in turn can influence plant growth conditions, which is called plant–soil feedback. Plant–soil feedback is known to be operative in a wide variety of ecosystems ranging

Effects of plant-soil feedback on tree seedling growth under arid conditions

NARCIS (Netherlands)

Meijer, S.S.; Holmgren, M.; Putten, van der W.H.

2011-01-01

Aims: Plants are able to influence their growing environment by changing biotic and abiotic soil conditions. These soil conditions in turn can influence plant growth conditions, which is called plant–soil feedback. Plant–soil feedback is known to be operative in a wide variety of ecosystems ranging

Analysis of variance of primary data on plant growth analysis Análise de variância dos dados primários na análise de crescimento vegetal

Directory of Open Access Journals (Sweden)

Adelson Paulo Araújo

2003-01-01

Full Text Available Plant growth analysis presents difficulties related to statistical comparison of growth rates, and the analysis of variance of primary data could guide the interpretation of results. The objective of this work was to evaluate the analysis of variance of data from distinct harvests of an experiment, focusing especially on the homogeneity of variances and the choice of an adequate ANOVA model. Data from five experiments covering different crops and growth conditions were used. From the total number of variables, 19% were originally homoscedastic, 60% became homoscedastic after logarithmic transformation, and 21% remained heteroscedastic after transformation. Data transformation did not affect the F test in one experiment, whereas in the other experiments transformation modified the F test usually reducing the number of significant effects. Even when transformation has not altered the F test, mean comparisons led to divergent interpretations. The mixed ANOVA model, considering harvest as a random effect, reduced the number of significant effects of every factor which had the F test modified by this model. Examples illustrated that analysis of variance of primary variables provides a tool for identifying significant differences in growth rates. The analysis of variance imposes restrictions to experimental design thereby eliminating some advantages of the functional growth analysis.A análise de crescimento vegetal apresenta dificuldades relacionadas à comparação estatística das curvas de crescimento, e a análise de variância dos dados primários pode orientar a interpretação dos resultados. Este trabalho objetivou avaliar a análise de variância de dados de distintas coletas de um experimento, abordando particularmente a homogeneidade das variâncias e a escolha do modelo adequado de ANOVA. Foram utilizados dados de cinco experimentos com diferentes culturas e condições de crescimento. Do total de variáveis, 19% foram originalmente

Basic regulatory principles of Escherichia coli's electron transport chain for varying oxygen conditions.

Science.gov (United States)

Henkel, Sebastian G; Ter Beek, Alexander; Steinsiek, Sonja; Stagge, Stefan; Bettenbrock, Katja; de Mattos, M Joost Teixeira; Sauter, Thomas; Sawodny, Oliver; Ederer, Michael

2014-01-01

For adaptation between anaerobic, micro-aerobic and aerobic conditions Escherichia coli's metabolism and in particular its electron transport chain (ETC) is highly regulated. Although it is known that the global transcriptional regulators FNR and ArcA are involved in oxygen response it is unclear how they interplay in the regulation of ETC enzymes under micro-aerobic chemostat conditions. Also, there are diverse results which and how quinones (oxidised/reduced, ubiquinone/other quinones) are controlling the ArcBA two-component system. In the following a mathematical model of the E. coli ETC linked to basic modules for substrate uptake, fermentation product excretion and biomass formation is introduced. The kinetic modelling focusses on regulatory principles of the ETC for varying oxygen conditions in glucose-limited continuous cultures. The model is based on the balance of electron donation (glucose) and acceptance (oxygen or other acceptors). Also, it is able to account for different chemostat conditions due to changed substrate concentrations and dilution rates. The parameter identification process is divided into an estimation and a validation step based on previously published and new experimental data. The model shows that experimentally observed, qualitatively different behaviour of the ubiquinone redox state and the ArcA activity profile in the micro-aerobic range for different experimental conditions can emerge from a single network structure. The network structure features a strong feed-forward effect from the FNR regulatory system to the ArcBA regulatory system via a common control of the dehydrogenases of the ETC. The model supports the hypothesis that ubiquinone but not ubiquinol plays a key role in determining the activity of ArcBA in a glucose-limited chemostat at micro-aerobic conditions.

Effect of growth conditions on the photovoltaic efficiency of poly(terthiophene) based photoelectrochemical cells

International Nuclear Information System (INIS)

Tsekouras, George; Too, Chee O.; Wallace, Gordon G.

2005-01-01

Conditions associated with the electrochemical growth of poly(terthiophene) (PTTh) were shown to have a considerable effect on photovoltaic (PV) performance indicators, namely, short-circuit-current (I sc ), open-circuit-voltage (V oc ), fill-factor (FF) and power-conversion-efficiency (PCE). The solvent and electrochemical technique used during growth were found to have an effect on PV performance. Increasing the upper potential limit associated with growth by cyclic voltammetry (CV) was found to decrease PV efficiency. The use of higher temperatures during growth was found to improve PV performance. Conditions associated with the electrochemical growth of PTTh were found to affect PV performance because of resultant changes to the polymer morphology. Such changes were characterised using scanning electron microscopy (SEM). In general, PTTh morphologies that exhibited increased porosity gave better PV performance by increasing the contact area between the PTTh and the liquid electrolyte. Combining the optimum conditions for the electrochemical growth of PTTh yielded a photoelectrochemical cell (PEC) showing I sc = 888 μA cm -2 , V oc 152 mV, FF = 37.3% and PCE = 0.101% under halogen light (solar simulated) intensity of 500 W m -2

Effect of Different Growth Conditions on Certain Biochemical Parameters of Different Cyanobacterial Strains

Directory of Open Access Journals (Sweden)

Hammouda, O. E.

2012-01-01

Full Text Available Aims: Variation in the traditional growth medium conditions to enhance the production of lipids, carbohydrates, protein and the free amino acids content of three cyanobacterial species. Methodology and Results: Three species of cyanobacteria (Anabaena laxa, Anabaena fertilissima and Nostoc muscorum were collected from the culture collection of Soils, Water and Environment Research Institute, Agriculture Research Center, Giza, Egypt, to investigate their biochemical composition under different growth conditions, using BG110 (nitrogen free as growth medium. These conditions were represented by control medium, static glucose medium with (1%, w/v, aerated medium (aerated by bubbling technique depending on CO2 normally existed in air with a concentration of 0.03%, molasses medium (0.7%, v/v and aerated medium enriched with glucose (1%, w/v. Lipid content, total carbohydrates, soluble proteins and free amino acids were determined at the previous conditions. Glucose at 0.7% (w/v was the most favorable for lipid production in A. laxa, where it exhibited the highest lipid content (427 μg/g fresh wt.. Increasing molasses concentration up to 0.7% (v/v produced an increase in lipid contents of the tested cyanobacterial strains. The highest lipid content of both N. muscorum (366.2 μg/g fresh wt. and A. laxa (357.4 μg/g fresh wt. were recorded at molasses concentrations of 0.1 and 0.7% (v/v, respectively. A. laxa expressed high significant values for both proteins (31.6 μg/mL and free amino acids (40.5 mg/g dry wt. after 6 days of incubation period under aerated enriched glucose condition (1%, w/v. Also, at the same growth conditions, A. fertilissima exhibited high significant values for carbohydrates at 4th day (876.8 mg/g dry wt.. Conclusion, significance and impact of study: Aerated enriched glucose medium (1%, w/v was the best growth medium condition used in the present study.

On the conditions required for vacancy loop growth in irradiated metals and alloys

International Nuclear Information System (INIS)

Hayns, M.R.

1980-07-01

A simple theoretical model is investigated which allows the conditions under which vacancy dislocation loop growth is possible to be examined. This forms an extension of previous work in that bulk defect recombination is not ignored and the effects of vacancy thermal emission are included. Whilst the present work does not provide a kinetic model for vacancy loop growth it has been possible to examine the criteria required for stable growth in some detail. The effects of network dislocation density, temperature, damage rate, the influence of other critical sinks, notably voids and grain boundaries, and interstitial dislocation loops have been considered. The analogy with the growth conditions for cavities as voids is highlighted. A detailed comparison with experiment is not attempted as this is being considered separately. (author)

Time-varying parameter models for catchments with land use change: the importance of model structure

Science.gov (United States)

Pathiraja, Sahani; Anghileri, Daniela; Burlando, Paolo; Sharma, Ashish; Marshall, Lucy; Moradkhani, Hamid

2018-05-01

Rapid population and economic growth in Southeast Asia has been accompanied by extensive land use change with consequent impacts on catchment hydrology. Modeling methodologies capable of handling changing land use conditions are therefore becoming ever more important and are receiving increasing attention from hydrologists. A recently developed data-assimilation-based framework that allows model parameters to vary through time in response to signals of change in observations is considered for a medium-sized catchment (2880 km2) in northern Vietnam experiencing substantial but gradual land cover change. We investigate the efficacy of the method as well as the importance of the chosen model structure in ensuring the success of a time-varying parameter method. The method was used with two lumped daily conceptual models (HBV and HyMOD) that gave good-quality streamflow predictions during pre-change conditions. Although both time-varying parameter models gave improved streamflow predictions under changed conditions compared to the time-invariant parameter model, persistent biases for low flows were apparent in the HyMOD case. It was found that HyMOD was not suited to representing the modified baseflow conditions, resulting in extreme and unrealistic time-varying parameter estimates. This work shows that the chosen model can be critical for ensuring the time-varying parameter framework successfully models streamflow under changing land cover conditions. It can also be used to determine whether land cover changes (and not just meteorological factors) contribute to the observed hydrologic changes in retrospective studies where the lack of a paired control catchment precludes such an assessment.

Time-varying parameter models for catchments with land use change: the importance of model structure

Directory of Open Access Journals (Sweden)

S. Pathiraja

2018-05-01

Full Text Available Rapid population and economic growth in Southeast Asia has been accompanied by extensive land use change with consequent impacts on catchment hydrology. Modeling methodologies capable of handling changing land use conditions are therefore becoming ever more important and are receiving increasing attention from hydrologists. A recently developed data-assimilation-based framework that allows model parameters to vary through time in response to signals of change in observations is considered for a medium-sized catchment (2880 km2 in northern Vietnam experiencing substantial but gradual land cover change. We investigate the efficacy of the method as well as the importance of the chosen model structure in ensuring the success of a time-varying parameter method. The method was used with two lumped daily conceptual models (HBV and HyMOD that gave good-quality streamflow predictions during pre-change conditions. Although both time-varying parameter models gave improved streamflow predictions under changed conditions compared to the time-invariant parameter model, persistent biases for low flows were apparent in the HyMOD case. It was found that HyMOD was not suited to representing the modified baseflow conditions, resulting in extreme and unrealistic time-varying parameter estimates. This work shows that the chosen model can be critical for ensuring the time-varying parameter framework successfully models streamflow under changing land cover conditions. It can also be used to determine whether land cover changes (and not just meteorological factors contribute to the observed hydrologic changes in retrospective studies where the lack of a paired control catchment precludes such an assessment.

The effect of varying talker identity and listening conditions on gaze behavior during audiovisual speech perception.

Science.gov (United States)

Buchan, Julie N; Paré, Martin; Munhall, Kevin G

2008-11-25

During face-to-face conversation the face provides auditory and visual linguistic information, and also conveys information about the identity of the speaker. This study investigated behavioral strategies involved in gathering visual information while watching talking faces. The effects of varying talker identity and varying the intelligibility of speech (by adding acoustic noise) on gaze behavior were measured with an eyetracker. Varying the intelligibility of the speech by adding noise had a noticeable effect on the location and duration of fixations. When noise was present subjects adopted a vantage point that was more centralized on the face by reducing the frequency of the fixations on the eyes and mouth and lengthening the duration of their gaze fixations on the nose and mouth. Varying talker identity resulted in a more modest change in gaze behavior that was modulated by the intelligibility of the speech. Although subjects generally used similar strategies to extract visual information in both talker variability conditions, when noise was absent there were more fixations on the mouth when viewing a different talker every trial as opposed to the same talker every trial. These findings provide a useful baseline for studies examining gaze behavior during audiovisual speech perception and perception of dynamic faces.

Growth curves and the international standard: How children's growth reflects challenging conditions in rural Timor-Leste.

Science.gov (United States)

Spencer, Phoebe R; Sanders, Katherine A; Judge, Debra S

2018-02-01

Population-specific growth references are important in understanding local growth variation, especially in developing countries where child growth is poor and the need for effective health interventions is high. In this article, we use mixed longitudinal data to calculate the first growth curves for rural East Timorese children to identify where, during development, deviation from the international standards occurs. Over an eight-year period, 1,245 children from two ecologically distinct rural areas of Timor-Leste were measured a total of 4,904 times. We compared growth to the World Health Organization (WHO) standards using z-scores, and modeled height and weight velocity using the SuperImposition by Translation And Rotation (SITAR) method. Using the Generalized Additive Model for Location, Scale and Shape (GAMLSS) method, we created the first growth curves for rural Timorese children for height, weight and body mass index (BMI). Relative to the WHO standards, children show early-life growth faltering, and stunting throughout childhood and adolescence. The median height and weight for this population tracks below the WHO fifth centile. Males have poorer growth than females in both z-BMI (p = .001) and z-height-for-age (p = .018) and, unlike females, continue to grow into adulthood. This is the most comprehensive investigation to date of rural Timorese children's growth, and the growth curves created may potentially be used to identify future secular trends in growth as the country develops. We show significant deviation from the international standard that becomes most pronounced at adolescence, similar to the growth of other Asian populations. Males and females show different growth responses to challenging conditions in this population. © 2017 Wiley Periodicals, Inc.

Changes In Growth Culture FDA Activity Under Changing Growth Conditions

DEFF Research Database (Denmark)

Jørgensen, Per Elberg; Eriksen, Thomas Juul; Jensen, Bjørn K.

1992-01-01

The FDA hydrolysis capacities and bacterial biomass concentrations (estimated by determination of ATP content) of growth cultures prepared from activated sludge and wastewater, were measured to find out whether the FDA activity would reflect bacterial biomass under different physiological states...... of the bacteria. The FDA activity/ATP ratio was calculated for different concentrations of autoclaved sludge. A faster decay rate of ATP relative to FDA hydrolysis activity was observed, thus causing changes in the ratio. Furthermore, comparison between values obtained from pure cultures and different soils...... revealed differences up to two orders of magnitude of the ratio. Based on these results it was concluded that the FDA activity should not be applied for measurements of viable biomass in environments in which different physiological conditions occur....

Linking Tree Growth Response to Measured Microclimate - A Field Based Approach

Science.gov (United States)

Martin, J. T.; Hoylman, Z. H.; Looker, N. T.; Jencso, K. G.; Hu, J.

2015-12-01

The general relationship between climate and tree growth is a well established and important tenet shaping both paleo and future perspectives of forest ecosystem growth dynamics. Across much of the American west, water limits growth via physiological mechanisms that tie regional and local climatic conditions to forest productivity in a relatively predictable way, and these growth responses are clearly evident in tree ring records. However, within the annual cycle of a forest landscape, water availability varies across both time and space, and interacts with other potentially growth limiting factors such as temperature, light, and nutrients. In addition, tree growth responses may lag climate drivers and may vary in terms of where in a tree carbon is allocated. As such, determining when and where water actually limits forest growth in real time can be a significant challenge. Despite these challenges, we present data suggestive of real-time growth limitation driven by soil moisture supply and atmospheric water demand reflected in high frequency field measurements of stem radii and cell structure across ecological gradients. The experiment was conducted at the Lubrecht Experimental Forest in western Montana where, over two years, we observed intra-annual growth rates of four dominant conifer species: Douglas fir, Ponderosa Pine, Engelmann Spruce and Western Larch using point dendrometers and microcores. In all four species studied, compensatory use of stored water (inferred from stem water deficit) appears to exhibit a threshold relationship with a critical balance point between water supply and demand. The occurrence of this point in time coincided with a decrease in stem growth rates, and the while the timing varied up to one month across topographic and elevational gradients, the onset date of growth limitation was a reliable predictor of overall annual growth. Our findings support previous model-based observations of nonlinearity in the relationship between

Positive and negative variations in capacitive images for given defects under varying experimental conditions

Science.gov (United States)

Li, Chen; Yin, Xiaokang; Li, Zhen; Li, Wei; Chen, Guoming

2018-04-01

Capacitive imaging (CI) technique is a novel electromagnetic NDE technique. The Quasi-static electromagnetic field from the carefully designed electrode pair will vary when the electrical properties of the sample change, leading to the possibility of imaging. It is observed that for a given specimen, the targeted features appear as different variations in capacitive images under different experimental conditions. In some cases, even opposite variations occur, which brings confusion to indication interpretation. It is thus thought interesting to embark on investigations into the cause and effects of the negative variation phenomenon. In this work, the positive and negative variations were first explained from the measurement sensitivity distribution perspective. This was then followed by a detailed analysis using finite element models in COMSOL. A parametric experimental study on a glass fiber composite plate with artificial defects was then carried out to investigate how the experimental conditions affect the variation.

Effects of sawdust thickness on the growth performance, environmental condition, and welfare quality of yellow broilers.

Science.gov (United States)

Shao, Dan; He, Jiao; Lu, Jian; Wang, Qiang; Chang, Lingling; Shi, Shou Rong; Bing, Tong Hai

2015-01-01

An experiment was conducted to evaluate the effect of litter thickness on growth performance, immune status, environmental condition, and welfare quality in yellow broilers. In total, 1,800 one-day-old Suqin yellow broilers were raised for 21 d. On d 22, 1,600 birds of similar BW (404±12 g) were randomly selected and placed into 20 indoor pens (8 birds/m2, 10 m2/pen). These birds were assigned to a litter treatment of 4, 8, 12, and 16 cm. Each treatment was repeated in five pens. The results showed that a thicker litter was related to increased BW, daily weight gain, and daily feed intake (Plitter thickness (P=0.320, P=0.353, respectively). Absolute and relative liver weights showed a significant linear response to increasing litter thickness (P=0.01, P=0.001, respectively). The litter moisture content, air ammonia, and CO2 content decreased, whereas the air dust content increased with increasing litter thickness (PLitter thickness had no effect on gait, plumage damage, hock burn or breast skin crusting (P = 0.076, P=0.964, P=0.131, P=0.401, respectively). Plumage cleanliness, foot pad dermatitis, hock swelling and breast blister varied significantly with litter thickness (P=0.027, P=0.011, P=0.014, P=0.042, respectively). The results of this study suggest that an increasing litter thickness has a beneficial effect on the growth performance, environmental condition and welfare of birds. © 2015 Poultry Science Association Inc.

Growth conditions determine the DNF2 requirement for symbiosis.

Directory of Open Access Journals (Sweden)

Fathi Berrabah

Full Text Available Rhizobia and legumes are able to interact in a symbiotic way leading to the development of root nodules. Within nodules, rhizobia fix nitrogen for the benefit of the plant. These interactions are efficient because spectacularly high densities of nitrogen fixing rhizobia are maintained in the plant cells. DNF2, a Medicago truncatula gene has been described as required for nitrogen fixation, bacteroid's persistence and to prevent defense-like reactions in the nodules. This manuscript shows that a Rhizobium mutant unable to differentiate is not sufficient to trigger defense-like reactions in this organ. Furthermore, we show that the requirement of DNF2 for effective symbiosis can be overcome by permissive growth conditions. The dnf2 knockout mutants grown in vitro on agarose or Phytagel as gelling agents are able to produce nodules fixing nitrogen with the same efficiency as the wild-type. However, when agarose medium is supplemented with the plant defense elicitor ulvan, the dnf2 mutant recovers the fix- phenotype. Together, our data show that plant growth conditions impact the gene requirement for symbiotic nitrogen fixation and suggest that they influence the symbiotic suppression of defense reactions in nodules.

Effect of Water Deficit Stress on Peach Growth under Commercial Orchard Management Conditions

Directory of Open Access Journals (Sweden)

M. Rahmati

2015-06-01

Full Text Available In order to study the sensitivity of vegetative growth to water deficit stress of a late-maturing peach (Prunus persica L. cv. Elberta under orchard conditions, an experiment was conducted as randomized complete-block design with three treatments and four repetitions in Shahdiran commercial orchard in Mashhad during 2011. Three irrigation treatments including 360 (low stress, 180 (moderate stress and 90 (severe stress m3ha-1week-1 using a drip irrigation system (minimum stem water potential near harvest: -1.2, -1.5 and -1.7 MPa, respectively from the mid-pit hardening stage (12th of June until harvest (23rd of Sep. applied. Predawn, stem and leaf water potentials, leaf photosynthesis, transpiration, stomatal conductance and leaf temperature, the number of new shoots on fruit bearing shoots and vegetative shoots lengths during growing season as well as leaf area at harvest were measured. The results showed that water deficit stress had negative effects on peach tree water status, thereby resulting in decreased leaf gas exchange and tree vegetative growth. As significant decreased assimilate production of tree was resulted from both decreased leaf assimilation rate (until about 23 % and 50 %, respectively under moderate and severe stress conditions compared to low stress conditions and decreased leaf area of tree (until about 57% and 79%, respectively under moderate and severe stress conditions compared to low stress conditions at harvest. The significant positive correlation between leaf water potential and vegetative growth of peach revealed that shoot growth would decrease by 30% and 50% of maximum at leaf water potential of –1.56 and –2.30 MPa, respectively.

Methods of forecasting crack growth rate under creep conditions

International Nuclear Information System (INIS)

Ol'kin, S.I.

1979-01-01

Using construction aluminium alloy application possibility of linear mechanics of the destruction for quantitative description of crack development process under creepage conditions is investigated. It is shown, that the grade dependence between the stress intensity coefficient and the crack growth rate takes place only at certain combination of the sample geometry and creepage parameters, and consequently, its applicability in every given case must necessarily be tested experimentally

Conditional random slope: A new approach for estimating individual child growth velocity in epidemiological research.

Science.gov (United States)

Leung, Michael; Bassani, Diego G; Racine-Poon, Amy; Goldenberg, Anna; Ali, Syed Asad; Kang, Gagandeep; Premkumar, Prasanna S; Roth, Daniel E

2017-09-10

Conditioning child growth measures on baseline accounts for regression to the mean (RTM). Here, we present the "conditional random slope" (CRS) model, based on a linear-mixed effects model that incorporates a baseline-time interaction term that can accommodate multiple data points for a child while also directly accounting for RTM. In two birth cohorts, we applied five approaches to estimate child growth velocities from 0 to 12 months to assess the effect of increasing data density (number of measures per child) on the magnitude of RTM of unconditional estimates, and the correlation and concordance between the CRS and four alternative metrics. Further, we demonstrated the differential effect of the choice of velocity metric on the magnitude of the association between infant growth and stunting at 2 years. RTM was minimally attenuated by increasing data density for unconditional growth modeling approaches. CRS and classical conditional models gave nearly identical estimates with two measures per child. Compared to the CRS estimates, unconditional metrics had moderate correlation (r = 0.65-0.91), but poor agreement in the classification of infants with relatively slow growth (kappa = 0.38-0.78). Estimates of the velocity-stunting association were the same for CRS and classical conditional models but differed substantially between conditional versus unconditional metrics. The CRS can leverage the flexibility of linear mixed models while addressing RTM in longitudinal analyses. © 2017 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.

Near-bed environmental conditions influencing cold-water coral growth on Viosca Knoll, Gulf of Mexico

Science.gov (United States)

Mienis, F.; Duineveld, G.; Davies, A. J.; Weering, T. V.; Ross, S.; Roberts, M.; Seim, H.

2010-12-01

transported to the area. Sediment trap samples show a similar pattern and high mass fluxes are found, varying between 1.1-4.5 gm-2day-1. High mass fluxes and turbidity values can be related to an increased input of material coming from the Mississippi River. The environmental conditions on Viosca Knoll resemble those recorded in CWC areas on the European margin. Even though oxygen values are low and high mass fluxes were recorded, the CWC ecosystem thrives at present. The proximity of the area to the Mississippi River may benefit the corals by increasing the food supply. Migration of zooplankton and episodes of fresh particle supply from surface water form the mechanisms of food delivery, influencing CWC growth. Subsequently baffling of particles between the coral framework likely increases lateral extension and reef growth.

Growth trajectories of the human embryonic head and periconceptional maternal conditions.

Science.gov (United States)

Koning, I V; Baken, L; Groenenberg, I A L; Husen, S C; Dudink, J; Willemsen, S P; Gijtenbeek, M; Koning, A H J; Reiss, I K M; Steegers, E A P; Steegers-Theunissen, R P M

2016-05-01

Can growth trajectories of the human embryonic head be created using 3D ultrasound (3D-US) and virtual reality (VR) technology, and be associated with second trimester fetal head size and periconceptional maternal conditions? Serial first trimester head circumference (HC) and head volume (HV) measurements were used to create reliable growth trajectories of the embryonic head, which were significantly associated with fetal head size and periconceptional maternal smoking, age and ITALIC! in vitro fertilization (IVF)/intra-cytoplasmic sperm injection (ICSI) treatment. Fetal growth is influenced by periconceptional maternal conditions. We selected 149 singleton pregnancies with a live born non-malformed fetus from the Rotterdam periconception cohort. Bi-parietal diameter and occipital frontal diameter to calculate HC, HV and crown-rump length (CRL) were measured weekly between 9 + 0 and 12 + 6 weeks gestational age (GA) using 3D-US and VR. Fetal HC was obtained from second trimester structural anomaly scans. Growth trajectories of the embryonic head were created with general additive models and linear mixed models were used to estimate associations with maternal periconceptional conditions as a function of GA and CRL, respectively. A total of 303 3D-US images of 149 pregnancies were eligible for embryonic head measurements (intra-class correlation coefficients >0.99). Associations were found between embryonic HC and fetal HC ( ITALIC! ρ = 0.617, ITALIC! P head measured by HC and HV (All ITALIC! P head may be of benefit in future early antenatal care. This study was funded by the Department of Obstetrics and Gynaecology, Erasmus MC University Medical Centre and Sophia Foundation for Medical Research, Rotterdam, The Netherlands (SSWO grant number 644). No competing interests are declared. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email

The effects of varying plasma parameters on silicon thin film growth by ECR plasma CVD

International Nuclear Information System (INIS)

Summers, S.; Reehal, H.S.; Shirkoohi, G.H.

2001-01-01

The technique of electron cyclotron resonance (ECR) plasma enhanced chemical vapour deposition (PECVD) is increasingly being used in electronic and photonic device applications. ECR offers a number of advantages including improved control of the deposition process, less damage to the growing film and the possibility of high deposition rates. ECR occurs in a plasma under appropriate magnetic and electric field conditions. In most cases, as in our system, this is achieved with a combination of 2.45 GHz microwave radiation and a 0.0875 T magnetic field, due to the use of standardized microwave supplies. We have studied the effects on silicon film growth of changing the magnetic field configuration to produce one or more planes of ECR within the system, and of changing the positions of the plane(s) relative to the deposition substrate. The films were grown in silane-hydrogen discharges. The magnetic field in our system was provided by two electromagnets. It was measured experimentally for a number of operating current values and then a detailed profile achieved by modelling using a proprietary software package. A process condition discharge under identical magnetic field configurations to growth was analysed by the use of a Langmuir probe and the results correlated with film properties determined by Raman spectroscopy and Dektak profilometry. (author)

Is the tourism-economic growth nexus time-varying? Bootstrap rolling-window causality analysis for the top ten tourist destinations

OpenAIRE

Shahbaz, Muhammad; Ferrer, Román; Hussain Shahzad, Syed Jawad; Haouas, Ilham

2017-01-01

This paper explores the time-varying causal nexus between tourism development and economic growth for the top ten tourist destinations in the world, namely China, France, Germany, Italy, Mexico, the Russian Federation, Spain, Turkey, the United Kingdom and the United States of America, over the period 1990-2015. To that end, a bootstrap rolling window Granger causality approach based on the modified Granger causality test developed by Toda and Yamamoto (1995) and Dolado and Lütkepohl (1996), ...

Growth of microbial mixed cultures under anaerobic, alkaline conditions

International Nuclear Information System (INIS)

Wenk, M.

1993-09-01

Cement and concrete are the most important engineered barrier materials in a repository for low- and intermediate-level waste and thus represent the most significant component of the total disposal inventory. Based on the chemical composition of the concrete used in the repository and the groundwater fluxes in the modelled host rock, it is to be expected that the pH in the near vicinity of the repository could exceed a value of 10.5 for more than a million years. The groundwater in the repository environment also has a limited carbon concentration. Since microorganisms will be present in a repository and can even find suitable living conditions within the waste itself, investigations were carried out in order to establish the extent to which microbial activity is possible under the extreme conditions of the repository near-field. For the investigations, alkalophilic cultures were enriched from samples from alkaline habitats and from Valanginian Marl. Anaerobic bacteria with fermentative, sulfate-reducing and methanogenic metabolism were selected. The growth and activity of the mixed cultures were studied under alkaline conditions and the dependence on pH and carbon concentration determined. All the mixed cultures investigated are alkalophilic. The optimum growth range for the cultures is between pH 9.0 and pH 10.0. The activity limit for the fermentative mixed culture is at pH 12, for the sulfate-reducers at pH 11 and for the methanogens at pH 10.5. Given the limited supply of carbon, the mixed cultures can only grow under slightly alkaline conditions. Only the fermentative cultures are capable of surviving with limited carbon supply at pH 13. (author) 24 figs., 18 tabs., 101 refs

Risky behavior and its effect on survival: snowshoe hare behavior under varying moonlight conditions

Science.gov (United States)

Gigliotti, Laura C.; Diefenbach, Duane R.

2018-01-01

Predation and predation risk can exert strong influences on the behavior of prey species. However, risk avoidance behaviors may vary among populations of the same species. We studied a population of snowshoe hares (Lepus americanus) near the southern edge of their range, in Pennsylvania. This population occupies different habitat types, experiences different environmental conditions, and are exposed to different predator species and densities than northern hare populations; therefore, they might exhibit differences in risk avoidance behaviors. We analyzed hare survival, movement rates, and habitat use under different levels of predation risk, as indexed by moonlight. Similar to previous work, we found snowshoe hare survival decreased with increased moon illumination during the winter, but we found differences in behavioral responses to increased predation risk. We found that snowshoe hares did not reduce movement rates during high‐risk nights, but instead found that hares selected areas with denser canopy cover, compared to low‐risk nights. We suggest that behavioral plasticity in response to predation risk allows populations of the same species to respond to localized conditions.

Modelling growth of Penicillium expansum and Aspergillus niger at constant and fluctuating temperature conditions.

Science.gov (United States)

Gougouli, Maria; Koutsoumanis, Konstantinos P

2010-06-15

The growth of Penicillium expansum and Aspergillus niger, isolated from yogurt production environment, was investigated on malt extract agar with pH=4.2 and a(w)=0.997, simulating yogurt, at isothermal conditions ranging from -1.3 to 35 degrees C and from 5 to 42.3 degrees C, respectively. The growth rate (mu) and (apparent) lag time (lambda) of the mycelium growth were modelled as a function of temperature using a Cardinal Model with Inflection (CMI). The results showed that the CMI can describe successfully the effect of temperature on fungal growth within the entire biokinetic range for both isolates. The estimated values of the CMI for mu were T(min)=-5.74 degrees C, T(max)=30.97 degrees C, T(opt)=22.08 degrees C and mu(opt)=0.221 mm/h for P. expansum and T(min)=10.13 degrees C, T(max)=43.13 degrees C, T(opt)=31.44 degrees C, and mu(opt)=0.840 mm/h for A. niger. The cardinal values for lambda were very close to the respective values for mu indicating similar temperature dependence of the growth rate and the lag time of the mycelium growth. The developed models were further validated under fluctuating temperature conditions using various dynamic temperature scenarios. The time-temperature conditions studied included single temperature shifts before or after the end of the lag time and continuous periodic temperature fluctuations. The prediction of growth at changing temperature was based on the assumption that after a temperature shift the growth rate is adopted instantaneously to the new temperature, while the lag time was predicted using a cumulative lag approach. The results showed that when the temperature shifts occurred before the end of the lag, they did not cause any significant additional lag and the observed total lag was very close to the cumulative lag predicted by the model. In experiments with temperature shifts after the end of the lag time, accurate predictions were obtained when the temperature profile included temperatures which were inside the

Features of Scots pine radial growth in conditions of provenance trial.

Science.gov (United States)

Kuzmin, Sergey; Kuzmina, Nina

2013-04-01

Provenance trial of Scots pine in Boguchany forestry of Krasnoyarsk krai is conducted on two different soils - dark-grey loam forest soil and sod-podzol sandy soil. Complex of negative factors for plant growth and development appears in dry conditions of sandy soil. It could results in decrease of resistance to diseases. Sandy soils in different climatic zones have such common traits as low absorbing capacity, poorness of elemental nutrition, low microbiological activity and moisture capacity, very high water permeability. But Scots pine trees growing in such conditions could have certain advantages and perspectives of use. In the scope of climate change (global warming) the study of Scots pine growth on sandy soil become urgent because of more frequent appearance of dry seasons. Purpose of the work is revelation of radial growth features of Scots pine with different origin in dry conditions of sandy soil and assessment of external factors influence. The main feature of radial growth of majority of studied pine provenances in conditions of sandy soil is presence of significant variation of increment with distinct decline in 25-years old with loss of tree rings in a number of cases. The reason of it is complex of factors: deficit of June precipitation and next following outbreak of fungal disease. Found «frost rings» for all trees of studied clymatypes in 1992 are the consequence of temperature decline from May 21 to June 2 - from 23 down to 2 degree Celsius. Perspective climatypes with biggest radial increments and least sensitivity to fungal disease were revealed. Eniseysk and Vikhorevka (from Krasnoyarsk krai and Irkutsk oblast)provenances of pine have the biggest radial increments, the least sensitivity to Cenangium dieback and smallest increments decline. These climatypes are in the group of perspective provenances and in present time they are recommended for wide trial in the region for future use in plantation forest growing. Kandalaksha (Murmansk oblast

Modification of growth conditions by mm-waves of wood-decaying mushrooms cultures

International Nuclear Information System (INIS)

Avagyan, I.A.

2016-01-01

Basidial macromycetes are not only value food, but can be used as source of such biological active compounds as the genistein, β -glucans, glioxal-oxidase et al. In this work we used different frequencies of extremely high frequency of electromagnetic irradiation (EHF EMI) with the aim of obtaining mushroom cultures with increased fermentative activity by the modulation of its growth conditions during growth on the peptone media. We investigated the influence of the non-thermal extremely high frequency electromagnetic waves in the interval of 45-53 GHz on β-glucosidase activities of two species of wood-decaying mushroom. In this study we examined the most popular edible wood-decaying mushroom Pleurotus ostreatus, which is wide-spread in the forests and commercial mushroom Lentinula edodes, under influence of such an abiotic factor as the extremely high frequency waves in the interval of 45 GHz - 53 GHz during 20 and 40 min on the 7th day of mycelial culture's growth. After the treatment of cultures we continued their growth and on the 3th day we examined the influence of these waves on fermentative activity of mycelial extracts. The some conditions of such treatment led to significant rising of β-glucosidase activities in the extracts of mycelial cultures

3-D simulations to investigate initial condition effects on the growth of Rayleigh-Taylor mixing

Energy Technology Data Exchange (ETDEWEB)

Andrews, Malcolm J [Los Alamos National Laboratory

2008-01-01

The effect of initial conditions on the growth rate of turbulent Rayleigh-Taylor (RT) mixing has been studied using carefully formulated numerical simulations. An integrated large-eddy simulation (ILES) that uses a finite-volume technique was employed to solve the three-dimensional incompressible Euler equations with numerical dissipation. The initial conditions were chosen to test the dependence of the RT growth parameters ({alpha}{sub b}, {alpha}{sub s}) on variations in (a) the spectral bandwidth, (b) the spectral shape, and (c) discrete banded spectra. Our findings support the notion that the overall growth of the RT mixing is strongly dependent on initial conditions. Variation in spectral shapes and bandwidths are found to have a complex effect of the late time development of the RT mixing layer, and raise the question of whether we can design RT transition and turbulence based on our choice of initial conditions. In addition, our results provide a useful database for the initialization and development of closures describing RT transition and turbulence.

Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

Science.gov (United States)

Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

2003-01-01

The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

Effects of varying environmental conditions on emissivity spectra of bulk lunar soils: Application to Diviner thermal infrared observations of the Moon

Science.gov (United States)

Donaldson Hanna, K. L.; Greenhagen, B. T.; Patterson, W. R.; Pieters, C. M.; Mustard, J. F.; Bowles, N. E.; Paige, D. A.; Glotch, T. D.; Thompson, C.

2017-02-01

Currently, few thermal infrared measurements exist of fine particulate (samples (e.g. minerals, mineral mixtures, rocks, meteorites, and lunar soils) measured under simulated lunar conditions. Such measurements are fundamental for interpreting thermal infrared (TIR) observations by the Diviner Lunar Radiometer Experiment (Diviner) onboard NASA's Lunar Reconnaissance Orbiter as well as future TIR observations of the Moon and other airless bodies. In this work, we present thermal infrared emissivity measurements of a suite of well-characterized Apollo lunar soils and a fine particulate (sample as we systematically vary parameters that control the near-surface environment in our vacuum chamber (atmospheric pressure, incident solar-like radiation, and sample cup temperature). The atmospheric pressure is varied between ambient (1000 mbar) and vacuum (radiation is varied between 52 and 146 mW/cm2, and the sample cup temperature is varied between 325 and 405 K. Spectral changes are characterized as each parameter is varied, which highlight the sensitivity of thermal infrared emissivity spectra to the atmospheric pressure and the incident solar-like radiation. Finally spectral measurements of Apollo 15 and 16 bulk lunar soils are compared with Diviner thermal infrared observations of the Apollo 15 and 16 sampling sites. This comparison allows us to constrain the temperature and pressure conditions that best simulate the near-surface environment of the Moon for future laboratory measurements and to better interpret lunar surface compositions as observed by Diviner.

End-of-the-Year Economic Growth and Time-varying Expected Returns

DEFF Research Database (Denmark)

Møller, Stig Vinther; Rangvid, Jesper

. To explain these results, we show as the second main fi?nding of our paper that economic growth and growth in economic confidence (consumer con?dence and business con?dence) are strongly correlated during the fourth quarter, but not during the other quarters. In summary, we therefore show that when economic......We show that macroeconomic growth at the end of the year (fourth-quarter or December) strongly predicts the returns of the aggregate market, small- and large-cap stocks, portfolios sorted on book-to-market and dividend yields, bond returns, and international stock returns, whereas economic growth...... during the rest of the year does not predict returns. End-of-the-year economic growth rates contain considerably more information about expected returns than standard variables used to predict returns, are robust to the choice of macro variables, and work in-sample, out-of-sample, and in subsamples...

End-of-the-year economic growth and time-varying expected returns

DEFF Research Database (Denmark)

Møller, Stig Vinther; Rangvid, Jesper

. To explain these results, we show as the second main fi…nding of our paper that economic growth and growth in economic confidence (consumer con…dence and business con…dence) are strongly correlated during the fourth quarter, but not during the other quarters. In summary, we therefore show that when economic......We show that macroeconomic growth at the end of the year (fourth-quarter or December) strongly predicts the returns of the aggregate market, small- and large-cap stocks, portfolios sorted on book-to-market and dividend yields, bond returns, and international stock returns, whereas economic growth...... during the rest of the year does not predict returns. End-of-the-year economic growth rates contain considerably more information about expected returns than standard variables used to predict returns, are robust to the choice of macro variables, and work in-sample, out-of-sample, and in subsamples...

Short Communication Synergistic effect of rhizobia and plant growth promoting rhizobacteria on the growth and nodulation of lentil seedlings under axenic conditions

Directory of Open Access Journals (Sweden)

Muhammad Zafar-ul-Hye

2013-05-01

Full Text Available Plant growth promoting rhizobacteria (PGPR containing ACC-deaminase in combination with rhizobia can improve the growth and nodulation in plants by suppressing the endogenous level of ethylene. In the present study, ten strains, each of PGPR and rhizobia from the previously screened cultures were tested for their effect as co-inoculants on growth and nodulation of lentil in growth pouches under axenic conditions. Results showed that most of the combinations improved the lentil growth as compared to the un-inoculated control. Maximum increase in shoot length (1.87 fold, root length (1.97 fold and total biomass (1.98 fold over the un-inoculated control was observed in the treatment where the lentil seedlings were inoculated with the combination Z24P10. Co-inoculation also improved the nodulation in lentil and the maximum number of nodules plant-1 (24 nodules were observed in the combination Z22P10. However, there was no nodulation in few combinations. It is concluded that the co-inoculation with rhizobia and PGPR containing ACC-deaminase has improved the growth and nodulation in lentil under axenic conditions and the selected combinations may be evaluated in pot and field trials

Mapping and simulating systematics due to spatially varying observing conditions in DES science verification data

International Nuclear Information System (INIS)

Leistedt, B.; Peiris, H. V.; Elsner, F.; Benoit-Lévy, A.; Amara, A.

2016-01-01

Spatially varying depth and the characteristics of observing conditions, such as seeing, airmass, or sky background, are major sources of systematic uncertainties in modern galaxy survey analyses, particularly in deep multi-epoch surveys. We present a framework to extract and project these sources of systematics onto the sky, and apply it to the Dark Energy Survey (DES) to map the observing conditions of the Science Verification (SV) data. The resulting distributions and maps of sources of systematics are used in several analyses of DES–SV to perform detailed null tests with the data, and also to incorporate systematics in survey simulations. We illustrate the complementary nature of these two approaches by comparing the SV data with BCC-UFig, a synthetic sky catalog generated by forward-modeling of the DES–SV images. We analyze the BCC-UFig simulation to construct galaxy samples mimicking those used in SV galaxy clustering studies. We show that the spatially varying survey depth imprinted in the observed galaxy densities and the redshift distributions of the SV data are successfully reproduced by the simulation and are well-captured by the maps of observing conditions. The combined use of the maps, the SV data, and the BCC-UFig simulation allows us to quantify the impact of spatial systematics on N(z), the redshift distributions inferred using photometric redshifts. We conclude that spatial systematics in the SV data are mainly due to seeing fluctuations and are under control in current clustering and weak-lensing analyses. However, they will need to be carefully characterized in upcoming phases of DES in order to avoid biasing the inferred cosmological results. Finally, the framework presented here is relevant to all multi-epoch surveys and will be essential for exploiting future surveys such as the Large Synoptic Survey Telescope, which will require detailed null tests and realistic end-to-end image simulations to correctly interpret the deep, high

Human conditions of insulin-like growth factor-I (IGF-I) deficiency

Science.gov (United States)

2012-01-01

Insulin-like growth factor I (IGF-I) is a polypeptide hormone produced mainly by the liver in response to the endocrine GH stimulus, but it is also secreted by multiple tissues for autocrine/paracrine purposes. IGF-I is partly responsible for systemic GH activities although it possesses a wide number of own properties (anabolic, antioxidant, anti-inflammatory and cytoprotective actions). IGF-I is a closely regulated hormone. Consequently, its logical therapeutical applications seems to be limited to restore physiological circulating levels in order to recover the clinical consequences of IGF-I deficiency, conditions where, despite continuous discrepancies, IGF-I treatment has never been related to oncogenesis. Currently the best characterized conditions of IGF-I deficiency are Laron Syndrome, in children; liver cirrhosis, in adults; aging including age-related-cardiovascular and neurological diseases; and more recently, intrauterine growth restriction. The aim of this review is to summarize the increasing list of roles of IGF-I, both in physiological and pathological conditions, underlying that its potential therapeutical options seem to be limited to those proven states of local or systemic IGF-I deficiency as a replacement treatment, rather than increasing its level upper the normal range. PMID:23148873

Human conditions of insulin-like growth factor-I (IGF-I deficiency

Directory of Open Access Journals (Sweden)

Puche Juan E

2012-11-01

Full Text Available Abstract Insulin-like growth factor I (IGF-I is a polypeptide hormone produced mainly by the liver in response to the endocrine GH stimulus, but it is also secreted by multiple tissues for autocrine/paracrine purposes. IGF-I is partly responsible for systemic GH activities although it possesses a wide number of own properties (anabolic, antioxidant, anti-inflammatory and cytoprotective actions. IGF-I is a closely regulated hormone. Consequently, its logical therapeutical applications seems to be limited to restore physiological circulating levels in order to recover the clinical consequences of IGF-I deficiency, conditions where, despite continuous discrepancies, IGF-I treatment has never been related to oncogenesis. Currently the best characterized conditions of IGF-I deficiency are Laron Syndrome, in children; liver cirrhosis, in adults; aging including age-related-cardiovascular and neurological diseases; and more recently, intrauterine growth restriction. The aim of this review is to summarize the increasing list of roles of IGF-I, both in physiological and pathological conditions, underlying that its potential therapeutical options seem to be limited to those proven states of local or systemic IGF-I deficiency as a replacement treatment, rather than increasing its level upper the normal range.

Weed spectrum and selectivity of tembotrione under varying environmental conditions

Directory of Open Access Journals (Sweden)

Gatzweiler, Elmar

2012-03-01

Full Text Available Tembotrione is a novel HPPD maize herbicide effective against a wide range of broadleaf and grass weeds. Some characteristics of this compound are described in this paper linking weed and crop responses following tembotrione applications to environmental parameters or use conditions. The activity of HPPD herbicides is very much dependant on the availability of light. Increasing illumination intensities following application augmented the activity levels of several comparable HPPD compounds in a growth chamber experiment. Tembotrione was shown to be more efficacious at low and high illumination intensities compared to standard herbicides applied at the same rate. At the high intensity, tembotrione retained its high efficacy from two up to four weeks after application showing a rapid and strong herbicidal activity. The activity following post-emergent treatments of tembotrione against broadleaf weeds was influenced by soil characteristics such as soil texture and organic matter content in a glasshouse test. The level of weed suppression clearly declined stronger on heavier soils than on lighter soils at a rather low application rate of 12.5 g a.i./ha and lower. This is a clear indication of residual efficacy of tembotrione. The selectivity of tembotrione was tested on numerous maize varieties following post-emergent treatment with tembotrione alone or in mixture with the safener isoxadifen-ethyl under field conditions in Germany in comparison to a standard herbicide. The level of crop phytotoxicity tended to increase in the following order: Tembotrione plus safener, standard herbicide to tembotrione alone. Only the mixture of tembotrione with safener did not cause significant adverse effects on maize. Another field experiment in the USA examined crop phytotoxicity using one maize variety in a situation of infurrow soil insecticide treatment followed by a post-emergent application of tembotrione (plus/minus isoxadifen-ethyl and standard herbicides

Growth of AlGaN under the conditions of significant gallium evaporation: phase separation and enhanced lateral growth

OpenAIRE

Mayboroda, I. O.; Knizhnik, A. A.; Grishchenko, Yu. V.; Ezubchenko, I. S.; Zanaveskin, Maxim L.; Presniakov, M. Yu.; Potapkin, B. V.; Ilyin, V. A.

2017-01-01

Growth kinetics of AlGaN in NH3 MBE under significant Ga desorption was studied. It was found that the addition of gallium stimulates 2D growth and provides better morphology of films compared to pure AlN. The effect was experimentally observed at up to 98% desorption of the impinging gallium. We found that, under the conditions of significant thermal desorption, larger amounts of gallium were retained at lateral boundaries of 3D surface features than at flat terraces because of the higher bi...

Bulk water phase and biofilm growth in drinking water at low nutrient conditions.

Science.gov (United States)

Boe-Hansen, Rasmus; Albrechtsen, Hans-Jørgen; Arvin, Erik; Jørgensen, Claus

2002-11-01

In this study, the bacterial growth dynamics of a drinking water distribution system at low nutrient conditions was studied in order to determine bacterial growth rates by a range of methods, and to compare growth rates in the bulk water phase and the biofilm. A model distribution system was used to quantify the effect of retention times at hydraulic conditions similar to those in drinking water distribution networks. Water and pipe wall samples were taken and examined during the experiment. The pipes had been exposed to drinking water at approximately 13 degrees C, for at least 385 days to allow the formation of a mature quasi-stationary biofilm. At retention times of 12 h, total bacterial counts increased equivalent to a net bacterial growth rate of 0.048 day(-1). The bulk water phase bacteria exhibited a higher activity than the biofilm bacteria in terms of culturability, cell-specific ATP content, and cell-specific leucine incorporation rate. Bacteria in the bulk water phase incubated without the presence of biofilm exhibited a bacterial growth rate of 0.30 day(-1). The biofilm was radioactively labelled by the addition of 14C-benzoic acid. Subsequently, a biofilm detachment rate of 0.013 day(-1) was determined by measuring the release of 14C-labelled bacteria of the biofilm. For the quasi-stationary phase biofilm, the detachment rate was equivalent to the net growth rate. The growth rates determined in this study by different independent experimental approaches were comparable and within the range of values reported in the literature.

Quantification of growth, yield and radiation use efficiency of promising cotton cultivars at varying nitrogen levels

International Nuclear Information System (INIS)

Wajid, A.; Ahmad, A.; Khaliq, T.; Alam, S.; Hussaun, A.; Hussain, K.; Naseem, W.; Usman, M.; Ahmad, S.

2010-01-01

Cotton cultivars response to different doses of nitrogen for radiation interception, canopy development, growth and seed yield were studied in 2006. The experiment was laid out in randomized complete block design with split arrangement under the climatic conditions of Bahawalpur. Data on seed yield, total dry matter (TDM), leaf area index (LAI), fraction of intercepted radiation (Fi), accumulated radiation interception during the growth season (Sa) and radiation use efficiency (RUE) were taken into account. TDM pattern showed sigmoid growth curve for both cultivars and nitrogen levels and showed strong relationship (R2 = 0.98) with the accumulated intercepted radiation (Sa) for the season. Mean maximum value of fraction of incident PAR (Fi) remained 90% at 120 days after sowing (DAS) harvest due to maximum crop canopy development. Cultivar NIAB-111 produced 0.81 g m/sup -2/ of TDM for each MJ of accumulated PAR and nitrogen at the rate of 185 kg ha/sup -1/ statistically proved to be better in converting radiation into dry matter production. (author)

Placental growth factor expression is reversed by antivascular endothelial growth factor therapy under hypoxic conditions.

Science.gov (United States)

Zhou, Ai-Yi; Bai, Yu-Jing; Zhao, Min; Yu, Wen-Zhen; Huang, Lv-Zhen; Li, Xiao-Xin

2014-08-01

Clinical trials have revealed that the antivascular endothelial growth factor (VEGF) therapies are effective in retinopathy of prematurity (ROP). But the low level of VEGF was necessary as a survival signal in healthy conditions, and endogenous placental growth factor (PIGF) is redundant for development. The purpose of this study was to elucidate the PIGF expression under hypoxia as well as the influence of anti-VEGF therapy on PIGF. CoCl2-induced hypoxic human umbilical vein endothelial cells (HUVECs) were used for an in vitro study, and oxygen-induced retinopathy (OIR) mice models were used for an in vivo study. The expression patterns of PIGF under hypoxic conditions and the influence of anti-VEGF therapy on PIGF were evaluated by quantitative reverse transcription-polymerase chain reaction (RTPCR). The retinal avascular areas and neovascularization (NV) areas of anti-VEGF, anti-PIGF and combination treatments were calculated. Retina PIGF concentration was evaluated by ELISA after treatment. The vasoactive effects of exogenous PIGF on HUVECs were investigated by proliferation and migration studies. PIGF mRNA expression was reduced by hypoxia in OIR mice, in HUVECs under hypoxia and anti-VEGF treatment. However, PIGF expression was reversed by anti-VEGF therapy in the OIR model and in HUVECs under hypoxia. Exogenous PIGF significantly inhibited HUVECs proliferation and migration under normal conditions, but it stimulated cell proliferation and migration under hypoxia. Anti-PIGF treatment was effective for neovascular tufts in OIR mice (P<0.05). The finding that PIGF expression is iatrogenically up-regulated by anti-VEGF therapy provides a consideration to combine it with anti-PIGF therapy.

Growth conditions of 0-group plaice

NARCIS (Netherlands)

Cardoso, J.F.M.F.; Freitas, V.; de Paoli, H.; Witte, J.IJ.; van der Veer, H.W.

2016-01-01

Growth studies based on population-based growth estimates are limited by the fact that they do not take into account differences in age/size structure within the population. To overcome these problems, otolith microstructure analysis is often used to estimate individual growth. Here, we analyse

Evaluation of growth and flowering of Chenopodium quinoa Willd. under Polish conditions

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Krzysztof Gęsiński

2012-12-01

Full Text Available The material presented refers to the estimation of growth and the flowering (Chenopodium quinoa Willd. under Polish conditions. The species has been a South-American pseudocereal cultivated in the traditional form in the Andean region for over 5 thousand years. Its advantage, apart from low soil and climate requirements, is that it shows high nutritive value. The Chenopodium quinoa protein is especially valuable with its amino acid composition which is better balanced than that of wheat or maize. It shows a better share of egzogenic aminoacids. Field examinations were carried out in 1999-2001 at the Experiment Station of Cultivar Testing at Chrząstowo. The experiment involved two cultivars from two various growing regions: America and Europe. Analyses were made to include development stages, plant growth dynamics, inflorescences development dynamics, inflorescence habit and flowering. Differences were recorded in the growth and development models of the cultivars researched. The European cultivar had a short compact inflorescence with a short flowering period, reaching 120 cm. American cultivar plants were high (160 cm; they showed a slower continuous growth, loose big-in-size inflorescence, and a long period of flowering. The plants ended their growing season over the flowering stage or seed formation. The adequate growth, the course of flowering and, as a result, a stable yielding of the European cultivar make the group suitable for the cultivation under Polish conditions. This breeding group should also be the parent material for the cultivation of the Polish cultivar of Chenopodium quinoa.

Modelling of the diffusion of pollutants in the atmosphere under varying conditions in large cultivated regions

International Nuclear Information System (INIS)

Wueneke, C.D.; Schultz, H.

1975-01-01

The most important routines of a numerical code based on the particle-in-cell-method for calculating the transport and the turbulent dispersion of inert and radio-active pollutants in the atmosphere have been programmed and have been tested successfully on the CDC computer CYBER 73/76 of the Regional Computer Centre for Niedersachsen in Hanover. Compared to the Gaussian plume model such a numerical code based on the particle-in-cell-method offers several advantages for the computation of the diffusion under varying conditions in large cultivated regions. (orig.) [de

Identification and growth conditions of purple non-sulfur photosynthetic bacteria isolated from palm oil mill effluent

International Nuclear Information System (INIS)

Radziah Ariffin

2004-01-01

An indigenous strain of the purple non-sulphur photosynthetic bacterium, isolated from palm oil mill effluent was presumably identified as species of Rhodopseudomonas palustris. Cultivation in synthetic medium under different conditions indicated that it gave maximum carotenoid and bacteriophyll synthesis under anaerobic conditions in the light with values of 12.6 and 108.1 mg/g dry cell weight respectively. These values were significantly higher than the pigment content obtained from aerobic cultivation. The specific growth rates in anaerobic was twice those in aerobic conditions in the light. Growth was not occurred in anaerobic or aerobic conditions in the dark. (Author)

Evaluation procedure of creep-fatigue defect growth in high temperature condition and application

International Nuclear Information System (INIS)

Park, Chang Gyu; Kim, Jong Bum; Lee, Jae Han

2003-12-01

This study proposed the evaluation procedure of creep-fatigue defect growth on the high-temperature cylindrical structure applicable to the KALIMER, which is developed by KAERI. Parameters used in creep defect growth and the evaluation codes with these parameters were analyzed. In UK, the evaluation procedure of defect initiation and growth were proposed with R5/R6 code. In Japan, simple evauation method was proposed by JNC. In France, RCC-MR A16 code which was evaluation procedure of the creep-fatigue defect initiation and growth related to leak before break was developed, and equations related to load conditions were modified lately. As an application example, the creep-fatigue defect growth on circumferential semi-elliptical surface defect in high temperature cylindrical structure was evaluated by RCC-MR A16

Initial growth of Bauhinia variegata trees under different colored shade nets and light conditions

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Renata Bachin Mazzini-Guedes

2014-12-01

Full Text Available Bauhinia variegata and B. variegata var. candida, commonly known as orchid trees, are small sized trees widely used for urban forestry and landscaping. Adult plants grow under full sun; in Brazil, however, seedlings are generally cultivated in commercial nurseries under natural half-shading. The objective of this study was to evaluate the influence of different colored shade nets and light conditions on the initial growth of B. variegata and B. variegata var. candida. The influence of six light conditions (red net with 50% shading; blue net with 50% shading; black net with 70% shading; black net with 50% shading; black net with 30% shading; and full sun on the initial growth of B. variegata and B. variegata var. candida were evaluated along 160 days, and growth relationships were calculated. Seedlings showed more efficiency on the use of photoassimilated compounds when grown under full sun. Such condition is the most appropriate for seedling production of B. variegata and B. variegata var. candida, contradicting what has been performed in practice.

Influence of culture conditions on growth and protein metabolism in chlorella pyrenoidosa

International Nuclear Information System (INIS)

Fernandez Gonzalez, J.; Mazon, M.P.; Batuecas, B.

1981-01-01

Growth and protein metabolism of chlorella pyrenoidosa under differents conditions of temperature, photoperiod and CO 2 concentration was studied. The optimum of biomas production was observed at 25 deg C, 40.000 ppm of CO 2 in air and a 20 h. light period, followed of 4 h. of darkness. Some variations in free aminoacids content was observed under differents conditions but no change did occur in protein. (author)

Metabolite profiling uncovers plasmid-induced cobalt limitation under methylotrophic growth conditions.

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Patrick Kiefer

2009-11-01

Full Text Available The introduction and maintenance of plasmids in cells is often associated with a reduction of growth rate. The reason for this growth reduction is unclear in many cases.We observed a surprisingly large reduction in growth rate of about 50% of Methylobacterium extorquens AM1 during methylotrophic growth in the presence of a plasmid, pCM80 expressing the tetA gene, relative to the wild-type. A less pronounced growth delay during growth under non-methylotrophic growth conditions was observed; this suggested an inhibition of one-carbon metabolism rather than a general growth inhibition or metabolic burden. Metabolome analyses revealed an increase in pool sizes of ethylmalonyl-CoA and methylmalonyl-CoA of more than 6- and 35-fold, respectively, relative to wild type, suggesting a strongly reduced conversion of these central intermediates, which are essential for glyoxylate regeneration in this model methylotroph. Similar results were found for M. extorquens AM1 pCM160 which confers kanamycin resistance. These intermediates of the ethylmalonyl-CoA pathway have in common their conversion by coenzyme B(12-dependent mutases, which have cobalt as a central ligand. The one-carbon metabolism-related growth delay was restored by providing higher cobalt concentrations, by heterologous expression of isocitrate lyase as an alternative path for glyoxylate regeneration, or by identification and overproduction of proteins involved in cobalt import.This study demonstrates that the introduction of the plasmids leads to an apparent inhibition of the cobalt-dependent enzymes of the ethylmalonyl-CoA pathway. Possible explanations are presented and point to a limited cobalt concentration in the cell as a consequence of the antibiotic stress.

Are oysters being bored to death? Influence of Cliona celata on Crassostrea virginica condition, growth and survival.

Science.gov (United States)

Carroll, John M; O'Shaughnessy, Kathryn A; Diedrich, Grant A; Finelli, Christopher M

2015-11-17

The boring sponge Cliona celata is a nuisance species that can have deleterious effects on eastern oyster Crassostrea virginica growth, condition, and survival. Surprisingly, however, these effects have not been well documented and when examined, results have been equi-vocal. In this study, we provide a direct comparison of growth, condition, and survival of sponge-colonized and uncolonized oysters in southeast North Carolina in 2 separate experiments. In the first experiment, sponge-colonized oysters exhibited significantly slower growth rates, reduced condition, and lower survival relative to uncolonized oysters, although results may have been confounded by oyster source. In the second experiment, using smaller oysters from the same source population, growth rate was again significantly reduced in colonized oysters relative to uncolonized oysters, however neither condition nor survival differed. In field surveys of the same population, colonized individuals across a range of sizes demonstrated significantly reduced condition. Further, condition index was negatively correlated with sponge biomass, which was positively correlated with oyster size, suggesting that the impact of the sponge changes with ontogeny. By investigating clearance rates, tissue isotopic and nutrient content, as well as caloric value, this study provides further evidence that sponge presence causes the oysters to divert energy into costly shell maintenance and repair at the expense of shell and somatic growth. Thus, although variable, our results demonstrate negative impacts of sponge infestation on oyster demographics, particularly as oysters grow larger.

Accounting for inherent variability of growth in microbial risk assessment.

Science.gov (United States)

Marks, H M; Coleman, M E

2005-04-15

Risk assessments of pathogens need to account for the growth of small number of cells under varying conditions. In order to determine the possible risks that occur when there are small numbers of cells, stochastic models of growth are needed that would capture the distribution of the number of cells over replicate trials of the same scenario or environmental conditions. This paper provides a simple stochastic growth model, accounting only for inherent cell-growth variability, assuming constant growth kinetic parameters, for an initial, small, numbers of cells assumed to be transforming from a stationary to an exponential phase. Two, basic, microbial sets of assumptions are considered: serial, where it is assume that cells transform through a lag phase before entering the exponential phase of growth; and parallel, where it is assumed that lag and exponential phases develop in parallel. The model is based on, first determining the distribution of the time when growth commences, and then modelling the conditional distribution of the number of cells. For the latter distribution, it is found that a Weibull distribution provides a simple approximation to the conditional distribution of the relative growth, so that the model developed in this paper can be easily implemented in risk assessments using commercial software packages.

Varying the agglomeration position of particles in a micro-channel using Acoustic Radiation Force beyond the resonance condition.

Science.gov (United States)

Dron, Olivier; Aider, Jean-Luc

2013-09-01

It is well-known that particles can be focused at mid-height of a micro-channel using Acoustic Radiation Force (ARF) tuned at the resonance frequency (h=λ/2). The resonance condition is a strong limitation to the use of acoustophoresis (particles manipulation using acoustic force) in many applications. In this study we show that it is possible to focus the particles anywhere along the height of a micro-channel just by varying the acoustic frequency, in contradiction with the resonance condition. This result has been thoroughly checked experimentally. The different physical properties as well as wall materials have been changed. The wall materials is finally the only critical parameters. One of the specificity of the micro-channel is the thickness of the carrier and reflector layer. A preliminary analysis of the experimental results suggests that the acoustic focusing beyond the classic resonance condition can be explained in the framework of the multilayered resonator proposed by Hill [1]. Nevertheless, further numerical studies are needed in order to confirm and fully understand how the acoustic pressure node can be moved over the entire height of the micro channel by varying the acoustic frequency. Despite some uncertainties about the origin of the phenomenon, it is robust and can be used for improved acoustic sorting or manipulation of particles or biological cells in confined set-ups. Copyright © 2013 Elsevier B.V. All rights reserved.

Arabidopsis Phosphatidic Acid Phosphohydrolases Are Essential for Growth under Nitrogen-Depleted Conditions

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Yushi Yoshitake

2017-10-01

Full Text Available The Arabidopsis homologs of mammalian lipin, PAH1 and PAH2, are cytosolic phosphatidic acid phosphohydrolases that are involved in phospholipid biosynthesis and are essential for growth under phosphate starvation. Here, pah1 pah2 double-knockout mutants were found to be hypersensitive to nitrogen (N starvation, whereas transgenic plants overexpressing PAH1 or PAH2 in the pah1 pah2 mutant background showed a similar growth phenotype as compared with wild type (WT under N starvation. The chlorophyll content of pah1 pah2 was significantly lower than that of WT, whereas the chlorophyll content and photosynthetic activity of the transgenic plants were significantly higher than those of WT under N-depleted conditions. Membrane glycerolipid composition of the pah1 pah2 mutants showed a significant decrease in the mole percent of chloroplast lipids to other phospholipids, whereas membrane lipid composition did not differ between transgenic plants and WT plants. Pulse-chase labeling experiments using plants grown under N-depleted conditions showed that, in pah1 pah2 plants, the labeling percent of chloroplast lipids such as phosphatidylglycerol and monogalactosyldiacylglycerol in the total glycerolipids was significantly lower than in WT. Moreover, N starvation-induced degradation of chloroplast structure was enhanced in pah1 pah2 mutants, and the membrane structure was recovered by complementation with PAH1. Thus, PAH is involved in maintaining chloroplast membrane structure and is required for growth under N-depleted conditions.

A portable anaerobic microbioreactor reveals optimum growth conditions for the methanogen Methanosaeta concilii.

Science.gov (United States)

Steinhaus, Benjamin; Garcia, Marcelo L; Shen, Amy Q; Angenent, Largus T

2007-03-01

Conventional studies of the optimum growth conditions for methanogens (methane-producing, obligate anaerobic archaea) are typically conducted with serum bottles or bioreactors. The use of microfluidics to culture methanogens allows direct microscopic observations of the time-integrated response of growth. Here, we developed a microbioreactor (microBR) with approximately 1-microl microchannels to study some optimum growth conditions for the methanogen Methanosaeta concilii. The microBR is contained in an anaerobic chamber specifically designed to place it directly onto an inverted light microscope stage while maintaining a N2-CO2 environment. The methanogen was cultured for months inside microchannels of different widths. Channel width was manipulated to create various fluid velocities, allowing the direct study of the behavior and responses of M. concilii to various shear stresses and revealing an optimum shear level of approximately 20 to 35 microPa. Gradients in a single microchannel were then used to find an optimum pH level of 7.6 and an optimum total NH4-N concentration of less than 1,100 mg/liter (<47 mg/liter as free NH3-N) for M. concilii under conditions of the previously determined ideal shear stress and pH and at a temperature of 35 degrees C.

Growth of preexisting abnormal grains in molybdenum under static and dynamic conditions

Energy Technology Data Exchange (ETDEWEB)

Noell, Philip J. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185-0889 (United States); Worthington, Daniel L. [Verily Life Sciences, 269 E. Grand Ave., South San Francisco, CA 94080, USA (United States); Taleff, Eric M., E-mail: taleff@utexas.edu [The University of Texas at Austin, Department of Mechanical Engineering, 204 East Dean Keeton St., Stop C2200, Austin, TX 78712 (United States)

2017-04-24

This investigation compares the growth rates of preexisting abnormal grains under both static and dynamic conditions. Abnormal grains several millimeters in length were produced in two commercial-purity molybdenum (Mo) materials by tensile straining at temperatures from 1923 to 2073 K (1650–1800 °C). This process is termed dynamic abnormal grain growth (DAGG) because it produces abnormal grains during concurrent plastic straining. DAGG creates abnormal grains at much lower temperatures than does static abnormal grain growth (SAGG). Abnormal grains created through DAGG were characterized with their surrounding microstructures and were then subjected to annealing treatments. Only one-third of the preexisting abnormal grains subsequently grew by SAGG. Among these, SAGG occurred only in those specimens that required the largest strains to initiate DAGG when creating the abnormal grain(s). The rates of boundary migration observed for SAGG were approximately two orders of magnitude slower than those for DAGG. When DAGG in one specimen was interrupted by extended static annealing, it did not recur when straining resumed. The dislocation substructure developed during hot deformation, which includes subgrains typical of five-power creep, is critically important to both DAGG and SAGG of preexisting abnormal grains under the conditions examined.

Influence of Different Growth Conditions on the Kefir Grains Production, used in the Kefiran Synthesis

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Carmen Rodica Pop

2014-11-01

Full Text Available The purpose of this study was to optimize the kefir grains biomass production, using milk as culture media. The kefir grains were cultured at different changed conditions (temperature, time, shaker rotating speed, culture media supplemented to evaluate their effects. Results showed that optimal culture conditions were using the organic skim milk, incubated at 25°C for 24 hours with a rotation rate of 125 rpm. According to results, the growth rate was 38.9 g/L for 24 h, at 25°C using the organic milk - OSM, 36.87 g/L during 24 hours, optimal time for propagation process gave 37.93 g/L kefir grains biomass when the effect of temperature level was tested. The homogenization of medium with shaker rotating induced a greater growth rate, it was obtained 38.9 g/L for 24 h, at 25°C using rotation rate at 125 rpm. The growing medium (conventional milk supplemented with different minerals and vitamins may lead to improve the growth conditions of kefir grains biomass. The optimization of the growth environment is very important for achieving the maximum production of kefir grains biomass, substrate necessary to obtain the polysaccharide kefiran

Growth condition dependency is the major cause of non-responsiveness upon genetic perturbation.

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Saman Amini

Full Text Available Investigating the role and interplay between individual proteins in biological processes is often performed by assessing the functional consequences of gene inactivation or removal. Depending on the sensitivity of the assay used for determining phenotype, between 66% (growth and 53% (gene expression of Saccharomyces cerevisiae gene deletion strains show no defect when analyzed under a single condition. Although it is well known that this non-responsive behavior is caused by different types of redundancy mechanisms or by growth condition/cell type dependency, it is not known what the relative contribution of these different causes is. Understanding the underlying causes of and their relative contribution to non-responsive behavior upon genetic perturbation is extremely important for designing efficient strategies aimed at elucidating gene function and unraveling complex cellular systems. Here, we provide a systematic classification of the underlying causes of and their relative contribution to non-responsive behavior upon gene deletion. The overall contribution of redundancy to non-responsive behavior is estimated at 29%, of which approximately 17% is due to homology-based redundancy and 12% is due to pathway-based redundancy. The major determinant of non-responsiveness is condition dependency (71%. For approximately 14% of protein complexes, just-in-time assembly can be put forward as a potential mechanistic explanation for how proteins can be regulated in a condition dependent manner. Taken together, the results underscore the large contribution of growth condition requirement to non-responsive behavior, which needs to be taken into account for strategies aimed at determining gene function. The classification provided here, can also be further harnessed in systematic analyses of complex cellular systems.

Influence of culture conditions on growth and protein metabolism in chlorella pyranosides

International Nuclear Information System (INIS)

Mazon Matanzo, M. P.; Fernandez Gonzalez, J.; Batuecas Suarez, B.

1981-01-01

Growth and protein metabolism of Chlorella pyranoside under different conditions of temperature, photo period and CO 2 concentration was studied. The optimum of biomass production was observed at 25 degree centigree, 40.000 ppm of CO 2 in air and a 20 h. light period, followed of 4 h. of darkness. Some variations in free aminoacids content was observed under different conditions but no change did occur in protein. (Author) 68 refs

Corrosion fatigue initiation and short crack growth behaviour of austenitic stainless steels under light water reactor conditions

International Nuclear Information System (INIS)

Seifert, H.P.; Ritter, S.; Leber, H.J.

2012-01-01

Highlights: ► Corrosion fatigue in austenitic stainless steels under light water reactor conditions. ► Identification of major parameters of influence on initiation and short crack growth. ► Critical system conditions for environmental reduction of fatigue initiation life. ► Comparison with the environmental factor (F env ) approach. - Abstract: The corrosion fatigue initiation and short crack growth behaviour of different wrought low-carbon and stabilised austenitic stainless steels was characterised under simulated boiling water reactor and pressurised water reactor primary water conditions by cyclic fatigue tests with sharply notched fracture mechanics specimens. The special emphasis was placed to the behaviour at low corrosion potentials and, in particular, to hydrogen water chemistry conditions. The major parameter effects and critical conjoint threshold conditions, which result in relevant environmental reduction and acceleration of fatigue initiation life and subsequent short crack growth, respectively, are discussed and summarised. The observed corrosion fatigue behaviour is compared with the fatigue evaluation procedures in codes and regulatory guidelines.

Growth Performance and Carcass Characteristics of Korean Native Ducks Fed Diets with Varying Levels of Limiting Amino Acids

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Y. K. Choo

2014-04-01

Full Text Available There are multiple experiments conducted with male Korean native ducks (KND to evaluate the optimal levels of limiting amino acids (AA. In Exp. 1, a total of 450 one-d-old male KNDs were divided into five groups with six replicates and fed experimental diets with varying levels of lysine, total sulfur amino acids (TSAA and threonine (T1, 0.90/0.74/0.70%; T2, 1.00/0.82/0.77%; T3, 1.10/0.90/0.85%; T4, 1.20/0.98/0.93%; T5, 1.30/1.07/1.01% to 21 d of age. In Exp. 2, one-d-old male KND were received and fed commercial starter diet from hatching to 21 d of age, and then divided into five groups with six replicates and fed one of five diets varying levels of lysine, TSAA, and threonine (T1, 0.73/0.62/0.54%; T2, 0.80/0.68/0.60%; T3, 0.87/0.74/0.65%; T4, 0.94/0.80/0.70%; T5, 1.01/0.86/0.75% during 22 to 56 d of age, respectively. The BW gain was linearly increased as dietary limiting AA levels increased to 1.20% lysine, 0.98% TSAA and 0.93% threonine. There were no significant differences in feed intake, gain:feed and uniformity among groups. In Exp. 2, the BW gain and gain:feed were not affected by dietary limiting AA levels. There were no significant differences in carcass characteristics and meat quality among groups. The growth performance and carcass characteristics did not show the significant response to increasing dietary limiting AA levels in KND during 22 to 56 d of age. In conclusion, the levels of lysine, TSAA and threonine necessary to maximize growth for starter phase were at least 1.20%, 0.98%, and 0.93%, respectively. On the other hands, KND require relatively low levels of limiting AA for late growth and carcass yield. The dietary levels of 0.73% lysine, 0.62% TSAA and 0.54% threonine appear to be adequate during growing phase.

Inhibition of cancer cell growth by exposure to a specific time-varying electromagnetic field involves T-type calcium channels.

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Carly A Buckner

Full Text Available Electromagnetic field (EMF exposures affect many biological systems. The reproducibility of these effects is related to the intensity, duration, frequency, and pattern of the EMF. We have shown that exposure to a specific time-varying EMF can inhibit the growth of malignant cells. Thomas-EMF is a low-intensity, frequency-modulated (25-6 Hz EMF pattern. Daily, 1 h, exposures to Thomas-EMF inhibited the growth of malignant cell lines including B16-BL6, MDA-MB-231, MCF-7, and HeLa cells but did not affect the growth of non-malignant cells. Thomas-EMF also inhibited B16-BL6 cell proliferation in vivo. B16-BL6 cells implanted in syngeneic C57b mice and exposed daily to Thomas-EMF produced smaller tumours than in sham-treated controls. In vitro studies showed that exposure of malignant cells to Thomas-EMF for > 15 min promoted Ca(2+ influx which could be blocked by inhibitors of voltage-gated T-type Ca(2+ channels. Blocking Ca(2+ uptake also blocked Thomas-EMF-dependent inhibition of cell proliferation. Exposure to Thomas-EMF delayed cell cycle progression and altered cyclin expression consistent with the decrease in cell proliferation. Non-malignant cells did not show any EMF-dependent changes in Ca(2+ influx or cell growth. These data confirm that exposure to a specific EMF pattern can affect cellular processes and that exposure to Thomas-EMF may provide a potential anti-cancer therapy.

Inhibition of cancer cell growth by exposure to a specific time-varying electromagnetic field involves T-type calcium channels.

Science.gov (United States)

Buckner, Carly A; Buckner, Alison L; Koren, Stan A; Persinger, Michael A; Lafrenie, Robert M

2015-01-01

Electromagnetic field (EMF) exposures affect many biological systems. The reproducibility of these effects is related to the intensity, duration, frequency, and pattern of the EMF. We have shown that exposure to a specific time-varying EMF can inhibit the growth of malignant cells. Thomas-EMF is a low-intensity, frequency-modulated (25-6 Hz) EMF pattern. Daily, 1 h, exposures to Thomas-EMF inhibited the growth of malignant cell lines including B16-BL6, MDA-MB-231, MCF-7, and HeLa cells but did not affect the growth of non-malignant cells. Thomas-EMF also inhibited B16-BL6 cell proliferation in vivo. B16-BL6 cells implanted in syngeneic C57b mice and exposed daily to Thomas-EMF produced smaller tumours than in sham-treated controls. In vitro studies showed that exposure of malignant cells to Thomas-EMF for > 15 min promoted Ca(2+) influx which could be blocked by inhibitors of voltage-gated T-type Ca(2+) channels. Blocking Ca(2+) uptake also blocked Thomas-EMF-dependent inhibition of cell proliferation. Exposure to Thomas-EMF delayed cell cycle progression and altered cyclin expression consistent with the decrease in cell proliferation. Non-malignant cells did not show any EMF-dependent changes in Ca(2+) influx or cell growth. These data confirm that exposure to a specific EMF pattern can affect cellular processes and that exposure to Thomas-EMF may provide a potential anti-cancer therapy.

Bulk water phase and biofilm growth in drinking water at low nutrient conditions

DEFF Research Database (Denmark)

Boe-Hansen, Rasmus; Albrechtsen, Hans-Jørgen; Arvin, Erik

2002-01-01

, and cell-specific leucine incorporation rate. Bacteria in the bulk water phase incubated without the presence of biofilmexhibited a bacterial growth rate of 0.30 day1. The biofilmwas radioactively labelled by the addition of 14C-benzoic acid. Subsequently, a biofilmdetachm ent rate of 0.013 day1...... the formation of a mature quasi-stationary biofilm. At retention times of 12 h, total bacterial counts increased equivalent to a net bacterial growth rate of 0.048 day1. The bulk water phase bacteria exhibited a higher activity than the biofilmbacteria in terms of culturability, cell-specific ATP content......In this study, the bacterial growth dynamics of a drinking water distribution system at low nutrient conditions was studied in order to determine bacterial growth rates by a range of methods, and to compare growth rates in the bulk water phase and the biofilm. A model distribution system was used...

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 - others: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

Effect of environmental and cultural conditions on medium pH and explant growth performance of Douglas-fir (Pseudotsuga menziesii shoot cultures [version 2; referees: 2 approved

Directory of Open Access Journals (Sweden)

Chien-Chih Chen

2015-05-01

Full Text Available The medium pH level of plant tissue cultures has been shown to be essential to many aspects of explant development and growth. Sensitivity or tolerance of medium pH change in vitro varies according to specific requirements of individual species. The objectives of this study are to 1 determine medium pH change over time in storage conditions and with presence of explants, 2 evaluate the effects of medium pH change on explant growth performance and 3 assess the effects of adding a pH stabilizer, 2-(N-morpholinoethanesulfonic acid (MES that is commonly used in Douglas-fir micropropagation medium. Vegetative buds were collected in the spring before breaking dormancy from juvenile and mature donor trees for conducting these evaluations. Medium, with or without MES, was pre-adjusted to five pH levels before adding MES, agar and autoclaving. Medium pH changes and explant growth parameters were measured at eight different incubation times. Overall, MES provided a more stable medium pH, relative to starting pH values, under both light and dark storage conditions as well as with presence of explants. A general trend of decreasing medium pH over time was found comparing explants from juvenile and mature donor genotypes. Explant height and weight growth increased over time, but differ among explants from juvenile and mature donor genotypes. Our findings suggest that a 21-day subculture practice may best sustain medium freshness, medium pH level and desirable explant growth.

Urban tree species show the same hydraulic response to vapor pressure deficit across varying tree size and environmental conditions.

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Lixin Chen

Full Text Available The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations.We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP. The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1 the influence of tree species and size on transpiration, and 2 the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH and tree canopy transpiration amount (E(c was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between G(c at VPD = 1 kPa (G(cref and the G(c sensitivity to VPD (-dG(c/dlnVPD across studied species as well as under contrasting soil water and R(s conditions in the urban area.We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of G(cref.

Urban tree species show the same hydraulic response to vapor pressure deficit across varying tree size and environmental conditions.

Science.gov (United States)

Chen, Lixin; Zhang, Zhiqiang; Ewers, Brent E

2012-01-01

The functional convergence of tree transpiration has rarely been tested for tree species growing under urban conditions even though it is of significance to elucidate the relationship between functional convergence and species differences of urban trees for establishing sustainable urban forests in the context of forest water relations. We measured sap flux of four urban tree species including Cedrus deodara, Zelkova schneideriana, Euonymus bungeanus and Metasequoia glyptostroboides in an urban park by using thermal dissipation probes (TDP). The concurrent microclimate conditions and soil moisture content were also measured. Our objectives were to examine 1) the influence of tree species and size on transpiration, and 2) the hydraulic control of urban trees under different environmental conditions over the transpiration in response to VPD as represented by canopy conductance. The results showed that the functional convergence between tree diameter at breast height (DBH) and tree canopy transpiration amount (E(c)) was not reliable to predict stand transpiration and there were species differences within same DBH class. Species differed in transpiration patterns to seasonal weather progression and soil water stress as a result of varied sensitivity to water availability. Species differences were also found in their potential maximum transpiration rate and reaction to light. However, a same theoretical hydraulic relationship between G(c) at VPD = 1 kPa (G(cref)) and the G(c) sensitivity to VPD (-dG(c)/dlnVPD) across studied species as well as under contrasting soil water and R(s) conditions in the urban area. We concluded that urban trees show the same hydraulic regulation over response to VPD across varying tree size and environmental conditions and thus tree transpiration could be predicted with appropriate assessment of G(cref).

Achieving Revenue Benchmarks Conditional on Growth Properties

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Dong Hyun Son

2017-05-01

Full Text Available This study examines whether certain firm characteristics, specifically growth properties, are associated with the likelihood of achieving market expectations for revenues, as well as which mechanism (revenue manipulation or expectation management growth firms utilize in order to avoid missing these expectations. The results show that growth firms are more likely to meet or exceed analyst revenue forecasts than non-growth firms. We also find that growth firms are more inclined to manipulate their reported revenues upwards, and less inclined to guide market expectations for revenues downward, in order to meet or beat expected revenues relative to non-growth firms. These findings suggest that window-dressing activities by growth firms may not be sustainable in the long-run and can misguide users of financial statements in their decision-making.

Comparison of Two Mechanistic Microbial Growth Models to Estimate Shelf Life of Perishable Food Package under Dynamic Temperature Conditions

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Dong Sun Lee

2014-01-01

Full Text Available Two mechanistic microbial growth models (Huang’s model and model of Baranyi and Roberts given in differential and integrated equation forms were compared in predicting the microbial growth and shelf life under dynamic temperature storage and distribution conditions. Literatures consistently reporting the microbial growth data under constant and changing temperature conditions were selected to obtain the primary model parameters, set up the secondary models, and apply them to predict the microbial growth and shelf life under fluctuating temperatures. When evaluated by general estimation behavior, bias factor, accuracy factor, and root-mean-square error, Huang’s model was comparable to Baranyi and Roberts’ model in the capability to estimate microbial growth under dynamic temperature conditions. Its simple form of single differential equation incorporating directly the growth rate and lag time may work as an advantage to be used in online shelf life estimation by using the electronic device.

Growth of conductive HfO{sub 2-x} thin films by reactive molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Hildebrandt, Erwin; Kurian, Jose; Alff, Lambert [Institut fuer Materialwissenschaft, TU Darmstadt (Germany); Kleebe, Hans-Joachim [Institut fuer Angewandte Geowissenschaften, TU Darmstadt (Germany)

2009-07-01

Thin films of oxygen deficient hafnium oxide were grown on single crystal c-cut and r-cut sapphire substrates by reactive molecular beam epitaxy. The oxidation conditions during growth were varied within a wide range using RF-activated oxygen. Hafnium oxide thin films were characterized using X-ray diffraction, resistivity measurements ({rho}-T) and transmission electron microscopy (TEM). The results show a dramatic increase in conductivity of the deposited oxygen deficient hafnium oxide thin films with decreasing oxidation conditions during growth. The electrical properties of deficient hafnium oxide thin films varied from insulating over semiconducting to conducting. X-ray diffraction data as well as TEM data rule out the possibility of conductivity due to metallic hafnium.

The influence of spatially and temporally varying oceanographic conditions on meroplanktonic metapopulations

Science.gov (United States)

Botsford, L. W.; Moloney, C. L.; Hastings, A.; Largier, J. L.; Powell, T. M.; Higgins, K.; Quinn, J. F.

We synthesize the results of several modelling studies that address the influence of variability in larval transport and survival on the dynamics of marine metapopulations distributed along a coast. Two important benthic invertebrates in the California Current System (CCS), the Dungeness crab and the red sea urchin, are used as examples of the way in which physical oceanographic conditions can influence stability, synchrony and persistence of meroplanktonic metapopulations. We first explore population dynamics of subpopulations and metapopulations. Even without environmental forcing, isolated local subpopulations with density-dependence can vary on time scales roughly twice the generation time at high adult survival, shifting to annual time scales at low survivals. The high frequency behavior is not seen in models of the Dungeness crab, because of their high adult survival rates. Metapopulations with density-dependent recruitment and deterministic larval dispersal fluctuate in an asynchronous fashion. Along the coast, abundance varies on spatial scales which increase with dispersal distance. Coastwide, synchronous, random environmental variability tends to synchronize these metapopulations. Climate change could cause a long-term increase or decrease in mean larval survival, which in this model leads to greater synchrony or extinction respectively. Spatially managed metapopulations of red sea urchins go extinct when distances between harvest refugia become greater than the scale of larval dispersal. All assessments of population dynamics indicate that metapopulation behavior in general dependes critically on the temporal and spatial nature of larval dispersal, which is largely determined by physical oceanographic conditions. We therfore explore physical influences on larval dispersal patterns. Observed trends in temperature and salinity applied to laboratory-determined responses indicate that natural variability in temperature and salinity can lead to variability in

The growth of Balanites aegyptiaca (L.) seedlings under varied ...

African Journals Online (AJOL)

Drought and soil fertility are the major factors that influence seedling survival and growth in arid areas, thus it is of paramount importance to establish optimum water requirements for ... Two weeks old seedlings in polythene bag (2kg) containing the standard potting mixture as growing media were used for the experiments.

The effect of growth conditions on the seed size/number trade-off.

Directory of Open Access Journals (Sweden)

Cloé Paul-Victor

2009-09-01

Full Text Available If the amount of resources allocated to reproduction (K is fixed, then an increase in seed mass (S can only be achieved by a decrease in seed number (n = K/S. Thus, log(n = log(K-log(S producing a slope of -1 when seed mass and number are plotted on log-log axes. However, in comparative studies, empirical support for a slope of -1 is limited and contentious, leading some to question the utility of this concept.First, we show that the expected slope depends on whether genotypes and species producing seeds of different mass are expected to reach the same adult size and that this in turn depends partly on the nature of growth. Second, we present experimental results using a population of recombinant inbred lines (RILs of Arabidopsis thaliana. When these RILs are grown in large pots with plentiful nutrients, they exhibit a trade-off between seed size and number with a slope of -1.68 (+/-0.18 on log-log axes. This occurs because of genetic correlations between seed mass and adult size so that, under the right growth conditions, lines producing lighter seeds have the genetic potential to produce larger rosettes and hence a greater total mass of seeds. We re-grew lines in small pots (10 and 40 mm diameter in a nutrient-poor substrate so that final adult size was heavily restricted by pot size.Under our growth conditions, small-seeded lines were unable to produce a greater total mass of seeds. Hence a trade-off emerged between seed mass and seed number with a slope of -1.166+/-0.319 on log-log axes in 40-mm diameter pots (close to the expected value of -1, although the slope was 0.132+/-0.263 in 10-mm diameter pots, demonstrating that the nature of the trade-off is sensitive to the growth conditions.

Salmon on the Edge: Growth and Condition of Juvenile Chum and Pink Salmon in the Northeastern Bering Sea

Science.gov (United States)

McPhee, M. V.

2016-02-01

As the Arctic and Subarctic regions warm, Pacific salmon (Oncorhynchus spp.) are expected to expand their range northward during ice-free periods in the Bering and Chukchi seas. The oscillating control hypothesis, which describes energetic differences of primary consumers between ice-associated and pelagic production phases, provides a framework for understanding how juvenile salmon might respond to changing conditions at the northern edge of their marine range. Additionally, relationships between growth/condition and temperature, salinity and bottom depth will help identify marine habitats supporting growth at the Arctic-Subarctic interface. In this study, we used survey data from NOAA and Arctic Ecosystem Integrated Survey project to 1) compare growth and condition of juvenile pink (O. gorbuscha) and chum (O. keta) salmon in the NE Bering Sea between warm and cool spring phases, and 2) describe relationships between summer environmental conditions and juvenile salmon growth and condition from 2006 - 2010. Chum and pink salmon were shorter, and chum salmon exhibited greater energy density, in years with cool springs; however, no other aspects of size and condition differed significantly between phases. Over all years, longer and more energy dense individuals of both species were caught at stations with greater bottom depths and in cooler sea-surface temperatures. We found little evidence that chlorophyll-a explained much of the variation in size or condition. We used insulin-like growth factor-1 (IGF-1) concentration as an indicator of relative growth rate for fishes sampled in 2009-2012 and that found juvenile salmon exhibited higher IGF-1 concentrations in 2010-2012 than in 2009. IGF-1 concentrations tended to increase with SST in chum salmon and with bottom depth (a proxy for distance from shore) in pink salmon, but more years of data are needed to adequately describe the relationship of IGF with environmental conditions. This study, although descriptive in

Growth and Yield Responses of Green Pepper (Capsicum annum L. to Manure Rates under Field and High Tunnel Conditions

Directory of Open Access Journals (Sweden)

Ima-obong I. DOMINIC

2017-03-01

Full Text Available The present study was conducted to determine growth and yield responses of green pepper to varying manure rates under field and high tunnel conditions. Experiment 1 was a pot experiment to evaluate three rates (0.5 and 10 t/ha of poultry manure (PM on green pepper production under high tunnel and open field conditions. Experiment 2 was to determine the performance of green pepper as influenced by different manure rates (0, 5 and 10 t/ha of PM, 300 kg/ha of NPK, 5 t/ha of PM + 200 kg of NPK and 10 t/ha of PM + 100 kg of NPK on the field. High tunnel produced about 3.1 fruits/plant that weighted 102.8 g, which was significantly higher than open field experiment in which 1.7 fruits/plant, with a medium weight of 32.3 g were noted. High tunnel enhanced successful production of green pepper during rainy season, whereas the open field production during the same season was near failure. Application of 10 t/ha of PM produced significantly larger fruits in the pot experiment. Good fertilizer effects on growth and yield components were recorded for the field study. Plant height, number of leaves and branches, number and weight of harvested fruit followed similar trend in 5 and 10 t/ha of PM which gave statistically similar results, and provided the best performance during the experiment. Application of 5 t/ha of PM produced the highest total fruits yield.

Early developed section of the jaw as an index of prenatal growth conditions in adult roe deer Capreolus capreolus

DEFF Research Database (Denmark)

Høye, Toke Thomas; Forchhammer, Mads Cedergreen

2006-01-01

-maturing bones are poor predictors of resource limitations during early development, as later benign conditions may lead to compensatory growth. We analysed the temporal growth dynamics of different sections of the lower jaw of roe deer Capreolus capreolus and found that the medioanterior section of the lower......Increasing evidence suggests that conditions in early life have important consequences for ultimate body size and fitness. Skeletal parts are often used as retrospective indices of body size and growth constraints because of their resistance to seasonal variation in resource availability. Yet, slow...... post partum and, as such, potentially leaves a fingerprint of prenatal growth conditions that is evident even in adult individuals. This supports earlier findings in ungulates of a shift in skeletal growth spurts after weaning, and suggests that the choice of skeletal index for population and cohort...

Modeling elm growth and Dutch elm disease susceptibility

Science.gov (United States)

Alberto Santini; Luisa Ghelardini

2012-01-01

Elm susceptibility to Dutch elm disease (DED) displays strong seasonal variation. The period during which elms can become infected and express DED symptoms is generally restricted to several weeks after growth resumption in spring, although it can vary among species, provenances, and environmental conditions. The reason for this phenomenon is not understood, but the...

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, Michael 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.

Kinetic modeling of growth and lipid body induction in Chlorella pyrenoidosa under heterotrophic conditions.

Science.gov (United States)

Sachdeva, Neha; Kumar, G Dinesh; Gupta, Ravi Prakash; Mathur, Anshu Shankar; Manikandan, B; Basu, Biswajit; Tuli, Deepak Kumar

2016-10-01

The aim of the present work was to develop a mathematical model to describe the biomass and (total) lipid productivity of Chlorella pyrenoidosa NCIM 2738 under heterotrophic conditions. Biomass growth rate was predicted by Droop's cell quota model, while changes observed in cell quota (utilization) under carbon excess conditions were used for the modeling and predicting the lipid accumulation rate. The model was simulated under non-limiting (excess) carbon and limiting nitrate concentration and validated with experimental data for the culture grown in batch (flask) mode under different nitrate concentrations. The present model incorporated two modes (growth and stressed) for the prediction of endogenous lipid synthesis/induction and aimed to predict the effect and response of the microalgae under nutrient starvation (stressed) conditions. MATLAB and Genetic Algorithm were employed for the prediction and validation of the model parameters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Estimating time-varying conditional correlations between stock and foreign exchange markets

Science.gov (United States)

Tastan, Hüseyin

2006-02-01

This study explores the dynamic interaction between stock market returns and changes in nominal exchange rates. Many financial variables are known to exhibit fat tails and autoregressive variance structure. It is well-known that unconditional covariance and correlation coefficients also vary significantly over time and multivariate generalized autoregressive model (MGARCH) is able to capture the time-varying variance-covariance matrix for stock market returns and changes in exchange rates. The model is applied to daily Euro-Dollar exchange rates and two stock market indexes from the US economy: Dow-Jones Industrial Average Index and S&P500 Index. The news impact surfaces are also drawn based on the model estimates to see the effects of idiosyncratic shocks in respective markets.

A systematic review of the routine monitoring of growth in children of primary school age to identify growth-related conditions.

Science.gov (United States)

Fayter, D; Nixon, J; Hartley, S; Rithalia, A; Butler, G; Rudolf, M; Glasziou, P; Bland, M; Stirk, L; Westwood, M

2007-06-01

To clarify the role of growth monitoring in primary school children, including obesity, and to examine issues that might impact on the effectiveness and cost-effectiveness of such programmes. Electronic databases were searched up to July 2005. Experts in the field were also consulted. Data extraction and quality assessment were performed on studies meeting the review's inclusion criteria. The performance of growth monitoring to detect disorders of stature and obesity was evaluated against National Screening Committee (NSC) criteria. In the 31 studies that were included in the review, there were no controlled trials of the impact of growth monitoring and no studies of the diagnostic accuracy of different methods for growth monitoring. Analysis of the studies that presented a 'diagnostic yield' of growth monitoring suggested that one-off screening might identify between 1:545 and 1:1793 new cases of potentially treatable conditions. Economic modelling suggested that growth monitoring is associated with health improvements [incremental cost per quality-adjusted life-year (QALY) of 9500 pounds] and indicated that monitoring was cost-effective 100% of the time over the given probability distributions for a willingness to pay threshold of 30,000 pounds per QALY. Studies of obesity focused on the performance of body mass index against measures of body fat. A number of issues relating to human resources required for growth monitoring were identified, but data on attitudes to growth monitoring were extremely sparse. Preliminary findings from economic modelling suggested that primary prevention may be the most cost-effective approach to obesity management, but the model incorporated a great deal of uncertainty. This review has indicated the potential utility and cost-effectiveness of growth monitoring in terms of increased detection of stature-related disorders. It has also pointed strongly to the need for further research. Growth monitoring does not currently meet all NSC

Influence of bovine lactoferrin on the growth of selected probiotic bacteria under aerobic conditions.

Science.gov (United States)

Chen, Po-Wen; Ku, Yu-We; Chu, Fang-Yi

2014-10-01

Bovine lactoferrin (bLf) is a natural glycoprotein, and it shows broad-spectrum antimicrobial activity. However, reports on the influences of bLf on probiotic bacteria have been mixed. We examined the effects of apo-bLf (between 0.25 and 128 mg/mL) on both aerobic and anaerobic cultures of probiotics. We found that bLf had similar effects on the growth of probiotics under aerobic or anaerobic conditions, and that it actively and significantly (at concentrations of >0.25 mg/mL) retarded the growth rate of Bifidobacterium bifidum (ATCC 29521), B. longum (ATCC 15707), B. lactis (BCRC 17394), B. infantis (ATCC 15697), Lactobacillus reuteri (ATCC 23272), L. rhamnosus (ATCC 53103), and L. coryniformis (ATCC 25602) in a dose-dependent manner. Otherwise, minimal inhibitory concentrations (MICs) were 128 or >128 mg/mL against B. bifidum, B. longum, B. lactis, L. reuteri, and L. rhamnosus (ATCC 53103). With regard to MICs, bLf showed at least four-fold lower inhibitory effect on probiotics than on pathogens. Intriguingly, bLf (>0.25 mg/mL) significantly enhanced the growth of Rhamnosus (ATCC 7469) and L. acidophilus (BCRC 14065) by approximately 40-200 %, during their late periods of growth. Supernatants produced from aerobic but not anaerobic cultures of L. acidophilus reduced the growth of Escherichia coli by about 20 %. Thus, bLf displayed a dose-dependent inhibitory effect on the growth of most probiotic strains under either aerobic or anaerobic conditions. An antibacterial supernatant prepared from the aerobic cultures may have significant practical use.

Effect of seed rate on growth, yield components and yield of mash bean grown under irrigated conditions of arid uplands of Balochistan, Pakistan

International Nuclear Information System (INIS)

Aachakzai, A.K.K.; Taran, S.A.

2011-01-01

A field experiment was carried out to investigate the effects of six different seed rates viz., 15, 17.5, 20, 22.5, 25 and 27.5 kg ha/sup -1/ on the growth, yield and yield attributes of mash bean Vigna mungo (L.) Hepper). This study was conducted for two consecutive years at the Agriculture Research Institute (ARI) under the existing semi-arid climatic, edaphic and water conditions of Quetta, Balochistan. Results revealed that plant population, pods plant/sup -1/, grain yield plant/sup -1/ and grain yield ha/sup -1/ were significantly (p<0.05 influenced by varying seed rates. However, other mentioned growth and yield attributes did not respond significantly. Statistically and numerically a maximum yield plant/sup -1/ (20.98 g) and yield ha/sup -1/ (3120 kg) were obtained in applied seed at the rate of 20 kg ha/sup -1/. Whereas, the same was obtained for plant population and plant height in applied seed rate of 25 kg ha/sup -1/. However, maximum number of branches plant/sup -1/ (4.22) was received for applied seeds at the rate of 15 kg ha/sup -1/. Therefore, seed at the rate of 20 kg ha/sup -1/ seems optimum which could be due to the most desirable population or planting density in the existing environmental conditions of Quetta. Results further revealed that only plant population plot/sup -1/ (r=0.481), and yield plant/sup -1/ (r=0.569) were significantly and positively correlated with grain yield ha/sup -1/, while all other remaining growth and yield attributes exhibited insignificant association with grain yield ha/sup -1/. Hence these two parameters i.e., planting density and grain yield plant/sup -1/ should be given more consideration while deciding about selection criteria for mash bean under irrigated conditions of arid uplands of Balochistan. (author)

Stress-Related Growth in Two Challenging Conditions

Czech Academy of Sciences Publication Activity Database

Šolcová, Iva; Tavel, P.

2017-01-01

Roč. 13, č. 1 (2017), č. článku 4. ISSN 1529-5168 Institutional support: RVO:68081740 Keywords : Mars-500 * cruise * personal growth * spirituality, cognitive growth * social growth Subject RIV: AN - Psychology OBOR OECD: Psychology (including human - machine relations)

Fibril growth kinetics link buffer conditions and topology of 3D collagen I networks.

Science.gov (United States)

Kalbitzer, Liv; Pompe, Tilo

2018-02-01

Three-dimensional fibrillar networks reconstituted from collagen I are widely used as biomimetic scaffolds for in vitro and in vivo cell studies. Various physicochemical parameters of buffer conditions for in vitro fibril formation are well known, including pH-value, ion concentrations and temperature. However, there is a lack of a detailed understanding of reconstituting well-defined 3D network topologies, which is required to mimic specific properties of the native extracellular matrix. We screened a wide range of relevant physicochemical buffer conditions and characterized the topology of the reconstituted 3D networks in terms of mean pore size and fibril diameter. A congruent analysis of fibril formation kinetics by turbidimetry revealed the adjustment of the lateral growth phase of fibrils by buffer conditions to be key in the determination of pore size and fibril diameter of the networks. Although the kinetics of nucleation and linear growth phase were affected by buffer conditions as well, network topology was independent of those two growth phases. Overall, the results of our study provide necessary insights into how to engineer 3D collagen matrices with an independent control over topology parameters, in order to mimic in vivo tissues in in vitro experiments and tissue engineering applications. The study reports a comprehensive analysis of physicochemical conditions of buffer solutions to reconstitute defined 3D collagen I matrices. By a combined analysis of network topology, i.e., pore size and fibril diameter, and the kinetics of fibril formation we can reveal the dependence of 3D network topology on buffer conditions, such as pH-value, phosphate concentration and sodium chloride content. With those results we are now able to provide engineering strategies to independently tune the topology parameters of widely used 3D collagen scaffolds based on the buffer conditions. By that, we enable the straightforward mimicking of extracellular matrices of in vivo

Photophysiological variability of microphytobenthic diatoms after growth in different types of culture conditions

NARCIS (Netherlands)

Forster, R.M.; Martin-Jézéquel, V.R.

2005-01-01

Microphytobenthic diatoms have great ecological importance in estuarine and coastal marine ecosystenis, yet many aspects of their physiology have not been investigated under controlled conditions. This work describes patterns in growth rates and photosynthesis in different types of culture for

Nutritional modulation of IGF-1 in relation to growth and body condition in Sceloporus lizards.

Science.gov (United States)

Duncan, Christine A; Jetzt, Amanda E; Cohick, Wendie S; John-Alder, Henry B

2015-05-15

Nutrition and energy balance are important regulators of growth and the growth hormone/insulin-like growth factor (GH/IGF) axis. However, our understanding of these functions does not extend uniformly to all classes of vertebrates and is mainly limited to controlled laboratory conditions. Lizards can be useful models to improve our understanding of the nutritional regulation of the GH/IGF-1 axis because many species are relatively easy to observe and manipulate both in the laboratory and in the field. In the present study, the effects of variation in food intake on growth, body condition, and hepatic IGF-1 mRNA levels were measured in (1) juveniles of Sceloporus jarrovii maintained on a full or 1/3 ration and (2) hatchlings of Sceloporus undulatus subjected to full or zero ration with or without re-feeding. These parameters plus plasma IGF-1 were measured in a third experiment using adults of S. undulatus subjected to full or zero ration with or without re-feeding. In all experiments, plasma corticosterone was measured as an anticipated indicator of nutritional stress. In S. jarrovii, growth and body condition were reduced but lizards remained in positive energy balance on 1/3 ration, and hepatic IGF-1 mRNA and plasma corticosterone were not affected in comparison to full ration. In S. undulatus, growth, body condition, hepatic IGF-1 mRNA, and plasma IGF-1 were all reduced by zero ration and restored by refeeding. Plasma corticosterone was increased in response to zero ration and restored by full ration in hatchlings but not adults of S. undulatus. These data indicate that lizards conform to the broader vertebrate model in which severe food deprivation and negative energy balance is required to attenuate systemic IGF-1 expression. However, when animals remain in positive energy balance, reduced food intake does not appear to affect systemic IGF-1. Consistent with other studies on lizards, the corticosterone response to reduced food intake is an unreliable indicator

Optimization of hydrostatic pressure at varied sonication conditions--power density, intensity, very low frequency--for isothermal ultrasonic sludge treatment.

Science.gov (United States)

Delmas, Henri; Le, Ngoc Tuan; Barthe, Laurie; Julcour-Lebigue, Carine

2015-07-01

This work aims at investigating for the first time the key sonication (US) parameters: power density (DUS), intensity (IUS), and frequency (FS) - down to audible range, under varied hydrostatic pressure (Ph) and low temperature isothermal conditions (to avoid any thermal effect). The selected application was activated sludge disintegration, a major industrial US process. For a rational approach all comparisons were made at same specific energy input (ES, US energy per solid weight) which is also the relevant economic criterion. The decoupling of power density and intensity was obtained by either changing the sludge volume or most often by changing probe diameter, all other characteristics being unchanged. Comprehensive results were obtained by varying the hydrostatic pressure at given power density and intensity. In all cases marked maxima of sludge disintegration appeared at optimum pressures, which values increased at increasing power intensity and density. Such optimum was expected due to opposite effects of increasing hydrostatic pressure: higher cavitation threshold then smaller and fewer bubbles, but higher temperature and pressure at the end of collapse. In addition the first attempt to lower US frequency down to audible range was very successful: at any operation condition (DUS, IUS, Ph, sludge concentration and type) higher sludge disintegration was obtained at 12 kHz than at 20 kHz. The same values of optimum pressure were observed at 12 and 20 kHz. At same energy consumption the best conditions - obtained at 12 kHz, maximum power density 720 W/L and 3.25 bar - provided about 100% improvement with respect to usual conditions (1 bar, 20 kHz). Important energy savings and equipment size reduction may then be expected. Copyright © 2014 Elsevier B.V. All rights reserved.

Simulation of fatigue crack growth under large scale yielding conditions

Science.gov (United States)

Schweizer, Christoph; Seifert, Thomas; Riedel, Hermann

2010-07-01

A simple mechanism based model for fatigue crack growth assumes a linear correlation between the cyclic crack-tip opening displacement (ΔCTOD) and the crack growth increment (da/dN). The objective of this work is to compare analytical estimates of ΔCTOD with results of numerical calculations under large scale yielding conditions and to verify the physical basis of the model by comparing the predicted and the measured evolution of the crack length in a 10%-chromium-steel. The material is described by a rate independent cyclic plasticity model with power-law hardening and Masing behavior. During the tension-going part of the cycle, nodes at the crack-tip are released such that the crack growth increment corresponds approximately to the crack-tip opening. The finite element analysis performed in ABAQUS is continued for so many cycles until a stabilized value of ΔCTOD is reached. The analytical model contains an interpolation formula for the J-integral, which is generalized to account for cyclic loading and crack closure. Both simulated and estimated ΔCTOD are reasonably consistent. The predicted crack length evolution is found to be in good agreement with the behavior of microcracks observed in a 10%-chromium steel.

Growth, photosynthetic pigments and production of essential oil of long-pepper under different light conditions

Directory of Open Access Journals (Sweden)

VANDIMILLI A. LIMA

Full Text Available ABSTRACT Piper hispidinervum C. DC. is popularly known as long-pepper and it owns a commercial value due to the essential oil it produces. Long-pepper oil is rich in safrole and eugenoln components that have insecticidal, fungicidal and bactericidal activity. It has been establish that to medicinal plants light influences not only growth but also essential oil production. The growth, the content of photosynthetic pigments and the essential oil production of Piper hispidinervum at greenhouses with different light conditions was evaluated. The treatments were characterized by cultivation of plants for 180 days under different light conditions, produced by shading greenhouses with 50% and 30% of natural incident irradiance, two colored shading nets red (RN and blue (BN both blocking 50% of the incident radiation and one treatment at full-sun (0% of shade. The results showed that the treatments of 50% shade and RN and BN were the ones which stimulated the greater growth. Blue and red light also had the best production of photosynthetic pigments. Essential oil yielded more under full sun therefore this is the most indicated condition to produce seedlings for the chemical and pharmaceutical industry.

Growth, photosynthetic pigments and production of essential oil of long-pepper under different light conditions.

Science.gov (United States)

Lima, Vandimilli A; Pacheco, Fernanda V; Avelar, Rafaella P; Alvarenga, Ivan C A; Pinto, José Eduardo B P; Alvarenga, Amauri A DE

2017-01-01

Piper hispidinervum C. DC. is popularly known as long-pepper and it owns a commercial value due to the essential oil it produces. Long-pepper oil is rich in safrole and eugenoln components that have insecticidal, fungicidal and bactericidal activity. It has been establish that to medicinal plants light influences not only growth but also essential oil production. The growth, the content of photosynthetic pigments and the essential oil production of Piper hispidinervum at greenhouses with different light conditions was evaluated. The treatments were characterized by cultivation of plants for 180 days under different light conditions, produced by shading greenhouses with 50% and 30% of natural incident irradiance, two colored shading nets red (RN) and blue (BN) both blocking 50% of the incident radiation and one treatment at full-sun (0% of shade). The results showed that the treatments of 50% shade and RN and BN were the ones which stimulated the greater growth. Blue and red light also had the best production of photosynthetic pigments. Essential oil yielded more under full sun therefore this is the most indicated condition to produce seedlings for the chemical and pharmaceutical industry.

Fatigue crack growth characteristics of the pressure vessel steel SA 508 Cl. 3 in various environments

International Nuclear Information System (INIS)

Lee, S. G.; Kim, I. S.; Park, Y. S.; Kim, J. W.; Park, C. Y.

2001-01-01

Fatigue tests in air and in room temperature water were performed to obtain comparable data and stable crack measuring conditions. In air environment, fatigue crack growth rate was increased with increasing temperature due to an increase in crack tip oxidation rate. In room temperature water, the fatigue crack growth rate was faster than in air and crack path varied on loading conditions. In simulated light water reactor (LWR) conditions, there was little environmental effect on the fatigue crack growth rate (FCGR) at low dissolved oxygen or at high loading frequency conditions. While the FCGR was enhanced at high oxygen condition, and the enhancement of crack growth rate increased as loading frequency decreased to a critical value. In fractography, environmentally assisted cracks, such as semi-cleavage and secondary intergranular crack, were found near sulfide inclusions only at high dissolved oxygen and low loading frequency condition. The high crack growth rate was related to environmentally assisted crack. These results indicated that environmentally assisted crack could be formed by the Electrochemical effect in specific loading condition

Corrosion study of API 5L x-series pipeline steels in 3.5% NaCl solution under varying conditions

International Nuclear Information System (INIS)

Shahid, M.; Qureshi, M.I.; Farooq, M.U.; Khan, M.I.

2003-01-01

Pipelines provide convenient and efficient means for mass transportation of variety of fluids, such as oil and gas, over varying distances. In the last two decades or so, pipeline designers focused mainly on the usage of larger sizes and higher operating pressures for achieving higher transportation efficiency. This has been accomplished through the provision of steels with progressive increase in yield strength coupled with good weldability and sufficient toughness to restrict crack propagation. In addition to higher strength and toughness, developing pipeline technologies have required improved resistance to corrosion, which has been tried with specific alloy additions and special control over non-metallic inclusions. Corrosion investigations were carried out on various grades of pipeline steels (API 5L X-46, X-52, X-56, X-60 and X- 70) under varying environmental conditions. This paper describes the results pertaining to corrosion behavior of the steels in 3.5% NaCl solutions in stagnant, turbulent and deaerated conditions. It was found that all grades corrode in this solution and their corrosion potentials and corrosion currents are in close vicinity of each other. Turbulent solutions, however, have shown an increase in corrosion rates whereas deaeration has revealed a relative decrease in aggressivity of the electrolyte. (author)

Environmental Growth Conditions of Trichoderma spp. Affects Indole Acetic Acid Derivatives, Volatile Organic Compounds, and Plant Growth Promotion

Science.gov (United States)

Nieto-Jacobo, Maria F.; Steyaert, Johanna M.; Salazar-Badillo, Fatima B.; Nguyen, Dianne Vi; Rostás, Michael; Braithwaite, Mark; De Souza, Jorge T.; Jimenez-Bremont, Juan F.; Ohkura, Mana; Stewart, Alison

2017-01-01

Trichoderma species are soil-borne filamentous fungi widely utilized for their many plant health benefits, such as conferring improved growth, disease resistance and abiotic stress tolerance to their hosts. Many Trichoderma species are able to produce the auxin phytohormone indole-3-acetic acid (IAA), and its production has been suggested to promote root growth. Here we show that the production of IAA is strain dependent and diverse external stimuli are associated with its production. In in vitro assays, Arabidopsis primary root length was negatively affected by the interaction with some Trichoderma strains. In soil experiments, a continuum effect on plant growth was shown and this was also strain dependent. In plate assays, some strains of Trichoderma spp. inhibited the expression of the auxin reporter gene DR5 in Arabidopsis primary roots but not secondary roots. When Trichoderma spp. and A. thaliana were physically separated, enhancement of both shoot and root biomass, increased root production and chlorophyll content were observed, which strongly suggested that volatile production by the fungus influenced the parameters analyzed. Trichoderma strains T. virens Gv29.8, T. atroviride IMI206040, T. sp. “atroviride B” LU132, and T. asperellum LU1370 were demonstrated to promote plant growth through volatile production. However, contrasting differences were observed with LU1370 which had a negative effect on plant growth in soil but a positive effect in plate assays. Altogether our results suggest that the mechanisms and molecules involved in plant growth promotion by Trichoderma spp. are multivariable and are affected by the environmental conditions. PMID:28232840

Fatigue-crack growth behavior of Type 347 stainless steels under simulated PWR water conditions

Energy Technology Data Exchange (ETDEWEB)

Hong, Seokmin; Min, Ki-Deuk; Yoon, Ji-Hyun; Kim, Min-Chul; Lee, Bong-Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

Fatigue crack growth rate (FCGR) curve of stainless steel exists in ASME code section XI, but it is still not considering the environmental effects. The longer time nuclear power plant is operated, the more the environmental degradation issues of materials pop up. There are some researches on fatigue crack growth rate of S304 and S316, but researches of FCGR of S347 used in Korea nuclear power plant are insufficient. In this study, the FCGR of S347 stainless steel was evaluated in the PWR high temperature water conditions. The FCGRs of S347 stainless steel under pressurized-water conditions were measured by using compact-tension (CT) specimens at different levels of dissolved oxygen (DO) and frequency. 1. FCGRs of SS347 were slower than that in ASME XI and environmental effect did not occur when frequency was higher than 1Hz. 2. Fatigue crack growth is accelerated by corrosion fatigue and it is more severe when frequency is slower than 0.1Hz. 3. Increase of crack tip opening time increased corrosion fatigue and it deteriorated environmental fatigue properties.

Detection of dynamically varying interaural time differences

DEFF Research Database (Denmark)

Kohlrausch, Armin; Le Goff, Nicolas; Breebaart, Jeroen

2010-01-01

of fringes surrounding the probe is equal to the addition of the effects of the individual fringes. In this contribution, we present behavioral data for the same experimental condition, called dynamically varying ITD detection, but for a wider range of probe and fringe durations. Probe durations varied...

Evolution PDEs with nonstandard growth conditions existence, uniqueness, localization, blow-up

CERN Document Server

Antontsev, Stanislav

2015-01-01

This monograph offers the reader a treatment of the theory of evolution PDEs with nonstandard growth conditions. This class includes parabolic and hyperbolic equations with variable or anisotropic nonlinear structure. We develop methods for the study of such equations and present a detailed account of recent results. An overview of other approaches to the study of PDEs of this kind is provided. The presentation is focused on the issues of existence and uniqueness of solutions in appropriate function spaces, and on the study of the specific qualitative properties of solutions, such as localization in space and time, extinction in a finite time and blow-up, or nonexistence of global in time solutions. Special attention is paid to the study of the properties intrinsic to solutions of equations with nonstandard growth.

Growth dynamics variation of different larch provenances under the mountain conditions in Poland

Energy Technology Data Exchange (ETDEWEB)

Kulej, M. [Univ. of Agriculture, Cracow (Poland). Section of Seed Production and Selection

1995-12-31

The results of 25-year investigations based on measurements and statistical analysis concerning the growth dynamics variation of larch provenances from the entire area of Poland are reported in this paper. This is the first larch provenance experiment in Poland under mountain conditions. The results obtained showed a significant variability among the provenances tested as regards the basic growth characters (height, d.b.h., growth index) at the age of 5, 8, 11, 15, 20 and 25 years. The larch from Klodzko and Proszkow turned out to be the best in respect of growth during the entire 25-years period. Decidedly bad were provenances from Marcule, Grojec, Rawa mazowiecka and Kroscienko. We cannot forecast the future growth of larch when trees are 5-years old since such prognosis may carry an error. However, on the basis of the results obtained it may be concluded that when trees are about 8 years old the stabilization of the position of individual provenances as regards growth takes place. The height growth curves for the individual provenances during the 25-years period (with exception of the provenance from Marcule) fall within the interval {+-} 0,5S from the compensated curve for the entire population studied. All larch provenances in the experiment had reached the height growth culmination. A greatest differentiation in respect of this character occurred in case of the provenances from Sudetes. 27 refs, 4 figs, 8 tabs

Growth dynamics variation of different larch provenances under the mountain conditions in Poland

Energy Technology Data Exchange (ETDEWEB)

Kulej, M [Univ. of Agriculture, Cracow (Poland). Section of Seed Production and Selection

1996-12-31

The results of 25-year investigations based on measurements and statistical analysis concerning the growth dynamics variation of larch provenances from the entire area of Poland are reported in this paper. This is the first larch provenance experiment in Poland under mountain conditions. The results obtained showed a significant variability among the provenances tested as regards the basic growth characters (height, d.b.h., growth index) at the age of 5, 8, 11, 15, 20 and 25 years. The larch from Klodzko and Proszkow turned out to be the best in respect of growth during the entire 25-years period. Decidedly bad were provenances from Marcule, Grojec, Rawa mazowiecka and Kroscienko. We cannot forecast the future growth of larch when trees are 5-years old since such prognosis may carry an error. However, on the basis of the results obtained it may be concluded that when trees are about 8 years old the stabilization of the position of individual provenances as regards growth takes place. The height growth curves for the individual provenances during the 25-years period (with exception of the provenance from Marcule) fall within the interval {+-} 0,5S from the compensated curve for the entire population studied. All larch provenances in the experiment had reached the height growth culmination. A greatest differentiation in respect of this character occurred in case of the provenances from Sudetes. 27 refs, 4 figs, 8 tabs

A necessary condition for dispersal driven growth of populations with discrete patch dynamics.

Science.gov (United States)

Guiver, Chris; Packman, David; Townley, Stuart

2017-07-07

We revisit the question of when can dispersal-induced coupling between discrete sink populations cause overall population growth? Such a phenomenon is called dispersal driven growth and provides a simple explanation of how dispersal can allow populations to persist across discrete, spatially heterogeneous, environments even when individual patches are adverse or unfavourable. For two classes of mathematical models, one linear and one non-linear, we provide necessary conditions for dispersal driven growth in terms of the non-existence of a common linear Lyapunov function, which we describe. Our approach draws heavily upon the underlying positive dynamical systems structure. Our results apply to both discrete- and continuous-time models. The theory is illustrated with examples and both biological and mathematical conclusions are drawn. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Pemodelan Markov Switching Dengan Time-varying Transition Probability

OpenAIRE

Savitri, Anggita Puri; Warsito, Budi; Rahmawati, Rita

2016-01-01

Exchange rate or currency is an economic variable which reflects country's state of economy. It fluctuates over time because of its ability to switch the condition or regime caused by economic and political factors. The changes in the exchange rate are depreciation and appreciation. Therefore, it could be modeled using Markov Switching with Time-Varying Transition Probability which observe the conditional changes and use information variable. From this model, time-varying transition probabili...

Increased water-use efficiency does not lead to enhanced tree growth under xeric and mesic conditions

NARCIS (Netherlands)

Lévesque, M.; Siegwolf, R.; Saurer, M.; Eilmann, B.; Rigling, A.

2014-01-01

Higher atmospheric CO2 concentrations (ca ) can under certain conditions increase tree growth by enhancing photosynthesis, resulting in an increase of intrinsic water-use efficiency (i WUE) in trees. However, the magnitude of these effects and their interactions with changing climatic conditions are

Growth, morphology, spectral and thermal studies of gel grown diclofenac acid crystals

Science.gov (United States)

Ramachandran, E.; Ramukutty, S.

2014-03-01

The crystal growth of diclofenac acid in silica gel is the first to be reported in literature. The growth parameters were varied to optimize the suitable growth condition. Single crystal X-ray diffraction method was used for the conformation of the crystal structure. Morphology studies showed that the growth is prominent along the b-axis and the prominent face is {002}. Fourier transform infrared spectral study was performed to identify the functional groups present in the crystal. Thermal stability and decomposition of the material were analyzed using thermo calorimetry in the temperature range 30-500 °C.

Effects of Short-Term Biosolarization Using Mature Compost and Industrial Tomato Waste Amendments on the Generation and Persistence of Biocidal Soil Conditions and Subsequent Tomato Growth.

Science.gov (United States)

Achmon, Yigal; Sade, Nir; Wilhelmi, María Del Mar Rubio; Fernández-Bayo, Jesus D; Harrold, Duff R; Stapleton, James J; VanderGheynst, Jean S; Blumwald, Eduardo; Simmons, Christopher W

2018-06-06

Conventional solarization and biosolarization with mature compost and tomato processing residue amendments were compared with respect to generation of pesticidal conditions and tomato ( Solanum lycopersicum L.) plant growth in treated soils. Soil oxygen depletion was examined as a response that has previously not been measured across multiple depths during biosolarization. For biosolarized soil, volatile fatty acids were found to accumulate concurrent with oxygen depletion, and the magnitude of these changes varied by soil depth. Two consecutive years of experimentation showed varying dissipation of volatile fatty acids from biosolarized soils post-treatment. When residual volatile fatty acids were detected in the biosolarized soil, fruit yield did not significantly differ from plants grown in solarized soil. However, when there was no residual volatile fatty acids in the soil at the time of planting, plants grown in biosolarized soil showed a significantly greater vegetation amount, fruit quantity, and fruit ripening than those of plants grown in solarized soil.

Unfolded protein response is required for Aspergillus oryzae growth under conditions inducing secretory hydrolytic enzyme production.

Science.gov (United States)

Tanaka, Mizuki; Shintani, Takahiro; Gomi, Katsuya

2015-12-01

Unfolded protein response (UPR) is an intracellular signaling pathway for adaptation to endoplasmic reticulum (ER) stress. In yeast UPR, Ire1 cleaves the unconventional intron of HAC1 mRNA, and the functional Hac1 protein translated from the spliced HAC1 mRNA induces the expression of ER chaperone genes and ER-associated degradation genes for the refolding or degradation of unfolded proteins. In this study, we constructed an ireA (IRE1 ortholog) conditionally expressing strain of Aspergillus oryzae, a filamentous fungus producing a large amount of amylolytic enzymes, and examined the contribution of UPR to ER stress adaptation under physiological conditions. Repression of ireA completely blocked A. oryzae growth under conditions inducing the production of hydrolytic enzymes, such as amylases and proteases. This growth defect was restored by the introduction of unconventional intronless hacA (hacA-i). Furthermore, UPR was observed to be induced by amylolytic gene expression, and the disruption of the transcriptional activator for amylolytic genes resulted in partial growth restoration of the ireA-repressing strain. In addition, a homokaryotic ireA disruption mutant was successfully generated using the strain harboring hacA-i as a parental host. These results indicated that UPR is required for A. oryzae growth to alleviate ER stress induced by excessive production of hydrolytic enzymes. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of ocean acidification on growth and otolith condition of juvenile scup, Stenotomus chrysops.

Science.gov (United States)

Perry, Dean M; Redman, Dylan H; Widman, James C; Meseck, Shannon; King, Andrew; Pereira, Jose J

2015-09-01

Increasing amounts of atmospheric carbon dioxide (CO2) from human industrial activities are causing changes in global ocean carbonate chemistry, resulting in a reduction in pH, a process termed "ocean acidification." It is important to determine which species are sensitive to elevated levels of CO2 because of potential impacts to ecosystems, marine resources, biodiversity, food webs, populations, and effects on economies. Previous studies with marine fish have documented that exposure to elevated levels of CO2 caused increased growth and larger otoliths in some species. This study was conducted to determine whether the elevated partial pressure of CO2 (pCO2) would have an effect on growth, otolith (ear bone) condition, survival, or the skeleton of juvenile scup, Stenotomus chrysops, a species that supports both important commercial and recreational fisheries. Elevated levels of pCO2 (1200-2600 μatm) had no statistically significant effect on growth, survival, or otolith condition after 8 weeks of rearing. Field data show that in Long Island Sound, where scup spawn, in situ levels of pCO2 are already at levels ranging from 689 to 1828 μatm due to primary productivity, microbial activity, and anthropogenic inputs. These results demonstrate that ocean acidification is not likely to cause adverse effects on the growth and survivability of every species of marine fish. X-ray analysis of the fish revealed a slightly higher incidence of hyperossification in the vertebrae of a few scup from the highest treatments compared to fish from the control treatments. Our results show that juvenile scup are tolerant to increases in seawater pCO2, possibly due to conditions this species encounters in their naturally variable environment and their well-developed pH control mechanisms.

Predicting plant performance under simultaneously changing environmental conditions – the interplay between temperature, light and internode growth

Directory of Open Access Journals (Sweden)

Katrin eKahlen

2015-12-01

Full Text Available Plant performance is significantly influenced by prevailing light and temperature conditions during plant growth and development. For plants exposed to natural fluctuations in abiotic environmental conditions it is however laborious and cumbersome to experimentally assign any contribution of individual environmental factors to plant responses. This study aimed at analyzing the interplay between light, temperature and internode growth based on model approaches. We extended the light-sensitive virtual plant model L-Cucumber by implementing a common Arrhenius function for appearance rates, growth rates and growth durations. For two greenhouse experiments, the temperature-sensitive model approach resulted in a precise prediction of cucumber mean internode lengths and number of internodes, as well as in accurately predicted patterns of individual internode lengths along the main stem. In addition, a system’s analysis revealed that environmental data averaged over the experimental period were not necessarily related to internode performance. Finally, the need for a species-specific parameterization of the temperature response function and related aspects in modelling temperature effects on plant development and growth is discussed.

Thermal shock behaviour of different tungsten grades under varying conditions

Energy Technology Data Exchange (ETDEWEB)

Wirtz, Oliver Marius

2012-07-19

Thermonuclear fusion power plants are a promising option to ensure the energy supply for future generations, but in many fields of research enormous challenges have to be faced. A major step on the way to the prototype fusion reactor DEMO will be ITER which is build in Cadarache, southern France. One of the most critical issues is the field of in-vessel materials and components, in particular the plasma facing materials (PFM). PFMs that will be used in a device like ITER have to withstand severe environmental conditions in terms of steady state and transient thermal loads as well as high particle fluxes such as hydrogen, helium and neutrons. Candidate wall materials are beryllium, tungsten and carbon based materials like CFC (carbon fibre composite). Tungsten is the most promising material for an application in the divertor region with very severe loading conditions and it will most probably also be used as PFM for DEMO. Hence, this work focuses on the investigation of the thermal shock response of different tungsten grades in order to understand the damage mechanisms and to identify material parameters which influence this behaviour under ITER and DEMO relevant operation conditions. Therefore the microstructure and the mechanical and thermal properties of five industrially manufactured tungsten grades were characterised. All five tungsten grades were exposed to transient thermal events with very high power densities of up to 1.27 GWm{sup -2} at varying base temperatures between RT and 600 C in the electron beam device JUDITH 1. The pulse numbers were limited to a maximum of 1000 in order to avoid immoderate workload on the test facility and to have enough time to cover a wide range of loading conditions. The results of this damage mapping enable to define different damage and cracking thresholds for the investigated tungsten grades and to identify certain material parameters which influence the location of these thresholds and the distinction of the induced

Thermal shock behaviour of different tungsten grades under varying conditions

International Nuclear Information System (INIS)

Wirtz, Oliver Marius

2012-01-01

Thermonuclear fusion power plants are a promising option to ensure the energy supply for future generations, but in many fields of research enormous challenges have to be faced. A major step on the way to the prototype fusion reactor DEMO will be ITER which is build in Cadarache, southern France. One of the most critical issues is the field of in-vessel materials and components, in particular the plasma facing materials (PFM). PFMs that will be used in a device like ITER have to withstand severe environmental conditions in terms of steady state and transient thermal loads as well as high particle fluxes such as hydrogen, helium and neutrons. Candidate wall materials are beryllium, tungsten and carbon based materials like CFC (carbon fibre composite). Tungsten is the most promising material for an application in the divertor region with very severe loading conditions and it will most probably also be used as PFM for DEMO. Hence, this work focuses on the investigation of the thermal shock response of different tungsten grades in order to understand the damage mechanisms and to identify material parameters which influence this behaviour under ITER and DEMO relevant operation conditions. Therefore the microstructure and the mechanical and thermal properties of five industrially manufactured tungsten grades were characterised. All five tungsten grades were exposed to transient thermal events with very high power densities of up to 1.27 GWm -2 at varying base temperatures between RT and 600 C in the electron beam device JUDITH 1. The pulse numbers were limited to a maximum of 1000 in order to avoid immoderate workload on the test facility and to have enough time to cover a wide range of loading conditions. The results of this damage mapping enable to define different damage and cracking thresholds for the investigated tungsten grades and to identify certain material parameters which influence the location of these thresholds and the distinction of the induced damages

Fatigue crack growth characteristics of nitrogen-alloyed type 347 stainless under operating conditions of a pressurized water reactor

Energy Technology Data Exchange (ETDEWEB)

Min, Ki Deuk; Hong, Seok Min; Kim, Dae Whan; Lee, Bong Sang [Korea Atomic Energy Research Institute, Nuclear Materials Safety Research Division, Daejeon (Korea, Republic of); Kim, Seon Jin [Hanyang University, Division of materials science and engineering, Seoul (Korea, Republic of)

2017-06-15

The fatigue crack growth behavior of Type 347 (S347) and Type 347N (S347N) stainless steel was evaluated under the operating conditions of a pressurized water reactor (PWR). These two materials showed different fatigue crack growth rates (FCGRs) according to the changes in dissolved oxygen content and frequency. Under the simulated PWR conditions for normal operation, the FCGR of S347N was lower than that of S347 and insensitive to the changes in PWR water conditions. The higher yield strength and better corrosion resistance of the nitrogen-alloyed Type 347 stainless steel might be a main cause of slower FCGR and more stable properties against changes in environmental conditions.

Genetic Adaptation to Growth Under Laboratory Conditions in Escherichia coli and Salmonella enterica

Directory of Open Access Journals (Sweden)

Anna Knöppel

2018-04-01

Full Text Available Experimental evolution under controlled laboratory conditions is becoming increasingly important to address various evolutionary questions, including, for example, the dynamics and mechanisms of genetic adaptation to different growth and stress conditions. In such experiments, mutations typically appear that increase the fitness under the conditions tested (medium adaptation, but that are not necessarily of interest for the specific research question. Here, we have identified mutations that appeared during serial passage of E. coli and S. enterica in four different and commonly used laboratory media and measured the relative competitive fitness and maximum growth rate of 111 genetically re-constituted strains, carrying different single and multiple mutations. Little overlap was found between the mutations that were selected in the two species and the different media, implying that adaptation occurs via different genetic pathways. Furthermore, we show that commonly occurring adaptive mutations can generate undesired genetic variation in a population and reduce the accuracy of competition experiments. However, by introducing media adaptation mutations with large effects into the parental strain that was used for the evolution experiment, the variation (standard deviation was decreased 10-fold, and it was possible to measure fitness differences between two competitors as small as |s| < 0.001.

Conditional expression of constitutively active estrogen receptor α in chondrocytes impairs longitudinal bone growth in mice

International Nuclear Information System (INIS)

Ikeda, Kazuhiro; Tsukui, Tohru; Imazawa, Yukiko; Horie-Inoue, Kuniko; Inoue, Satoshi

2012-01-01

Highlights: ► Conditional transgenic mice expressing constitutively active estrogen receptor α (caERα) in chondrocytes were developed. ► Expression of caERα in chondrocytes impaired longitudinal bone growth in mice. ► caERα affects chondrocyte proliferation and differentiation. ► This mouse model is useful for understanding the physiological role of ERαin vivo. -- Abstract: Estrogen plays important roles in the regulation of chondrocyte proliferation and differentiation, which are essential steps for longitudinal bone growth; however, the mechanisms of estrogen action on chondrocytes have not been fully elucidated. In the present study, we generated conditional transgenic mice, designated as caERα ColII , expressing constitutively active mutant estrogen receptor (ER) α in chondrocytes, using the chondrocyte-specific type II collagen promoter-driven Cre transgenic mice. caERα ColII mice showed retardation in longitudinal growth, with short bone lengths. BrdU labeling showed reduced proliferation of hypertrophic chondrocytes in the proliferating layer of the growth plate of tibia in caERα ColII mice. In situ hybridization analysis of type X collagen revealed that the maturation of hypertrophic chondrocytes was impaired in caERα ColII mice. These results suggest that ERα is a critical regulator of chondrocyte proliferation and maturation during skeletal development, mediating longitudinal bone growth in vivo.

Growth conditions of 0-group plaice Pleuronectes platessa in the western Wadden Sea as revealed by otolith microstructure analysis

Science.gov (United States)

Cardoso, Joana F. M. F.; Freitas, Vânia; de Paoli, Hélène; Witte, Johannes IJ.; van der Veer, Henk W.

2016-05-01

Growth studies based on population-based growth estimates are limited by the fact that they do not take into account differences in age/size structure within the population. To overcome these problems, otolith microstructure analysis is often used to estimate individual growth. Here, we analyse growth of 0-group plaice in the western Wadden Sea in two years: a year preceded by a mild winter (1995) and a year preceded by a severe winter (1996). Growth was analysed by combining information on individual growth based on otolith analysis with predictions of maximum growth (= under optimal food conditions) based on a Dynamic Energy Budget model. Otolith analysis revealed that settlement occurred earlier in 1995 than in 1996. In both years, one main cohort was found, followed by a group of late settlers. No differences in mean length-at-age were found between these groups. DEB modelling suggested that growth was not maximal during the whole growing season: realized growth (the fraction of maximum growth realized by 0-group plaice) declined in the summer, although this decline was relatively small. In addition, late settling individuals exhibited lower realized growth than individuals from the main cohort. This study confirms that growth conditions for 0-group plaice are not optimal and that a growth reduction occurs in summer, as suggested in previous studies.

The effect of growth conditions on flavonols and anthocyanins accumulation in green and red lettuce

OpenAIRE

Klaudia BRÜCKOVÁ; Oksana SYTAR; Marek ŢIVČÁK; Marian BRESTIC; Aleš LEBEDA

2016-01-01

The aim of the study was to investigate the effect of different growth conditions on anthocyanins and flavonols accumulation in leaves of green and red loose leaf lettuce (Lactuca sativa var. crispa). Lettuce plants were grown in three types of conditions, in greenhouse (I. variant), behind clear glass in field (II. variant) and in open field conditions (III. variant). Estimation of anthocyanins and flavonols content was done by non-destructive measurements with optical fluorescence sensor Mu...

Seasonal carbon storage and growth in Mediterranean tree seedlings under different water conditions.

Science.gov (United States)

Sanz-Pérez, Virginia; Castro-Díez, Pilar; Joffre, Richard

2009-09-01

In all Mediterranean-type ecosystems, evergreen and deciduous trees differing in wood anatomy, growth pattern and leaf habit coexist, suggesting distinct adaptative responses to environmental constraints. This study examined the effects of summer water stress on carbon (C) storage and growth in seedlings of three coexisting Mediterranean trees that differed in phenology and wood anatomy characteristics: Quercus ilex subsp. ballota (Desf.) Samp., Quercus faginea Lam. and Pinus halepensis L. Seedlings were subjected to two levels of watering during two consecutive summers and achieved a minimum of -0.5 and -2.5 MPa of predawn water potential in the control and water stress treatment, respectively. Both Quercus species concentrated their growth in the early growing season, demanding higher C in early spring but replenishing C-stores in autumn. These species allocated more biomass to roots, having larger belowground starch and lipid reserves. Quercus species differed in seasonal storage dynamics from P. halepensis. This species allocated most of its C to aboveground growth, which occurred gradually during the growing season, leading to fewer C-reserves. Soluble sugar and starch concentrations sharply declined in August in P. halepensis, probably because reserves support respiration demands as this species closed stomata earlier under water stress. Drought reduced growth of the three species, mainly in Q. faginea and P. halepensis, but not C-reserves, suggesting that growth under water stress conditions is not limited by C-availability.

An ultraviolet B condition that affects growth and defense in Arabidopsis.

Science.gov (United States)

Vandenbussche, Filip; Yu, Na; Li, Weidong; Vanhaelewyn, Lucas; Hamshou, Mohamad; Van Der Straeten, Dominique; Smagghe, Guy

2018-03-01

Ultraviolet B light (UV-B, 280-315 nm) is the shortest wavelength of the solar spectrum reaching the surface of the Earth. It has profound effects on plants, ranging from growth regulation to severe metabolic changes. Low level UV-B mainly causes photomorphogenic effects while higher levels can induce stress, yet these effects tend to overlap. Here we identified a condition that allows growth reduction without obvious detrimental stress in wild type Arabidopsis rosette plants. This condition was used to study the effects of a daily UV-B dose on plant characteristics of UV-B adapted plants in detail. Exploration of the transcriptome of developing leaves indicated downregulation of genes involved in stomata formation by UV-B, while at the same time genes involved in photoprotective pigment biosynthesis were upregulated. These findings correspond with a decreased stomatal density and increased UV-B absorbing pigments. Gene ontology analysis revealed upregulation of defense related genes and meta-analysis showed substantial overlap of the UV-B regulated transcriptome with transcriptomes of salicylate and jasmonate treated as well as herbivore exposed plants. Feeding experiments showed that caterpillars of Spodoptera littoralis are directly affected by UV-B, while performance of the aphid Myzus persicae is diminished by a plant mediated process. Copyright © 2017 Elsevier B.V. All rights reserved.

Growth and bromatologic value of Typha sp. under semi-arid conditions

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Jorge Messias Leal do Nascimento

2015-03-01

Full Text Available Typha sp. plants are rustic and have accelerated development. However, their real growth and potential to animal nutrition are not so well-known. This study aimed to evaluate the shoot biomass production, growth dynamics and chemicalbromatological composition of Typha sp. plants at different cutting heights, under semiarid conditions. A total of four cutting heights (60 cm, 100 cm, 140 cm and 180 cm were evaluated in a complete randomized design, with five replicates. Plants presented similar production of leaf biomass and heart of palm up to 140 cm height, with higher leaf accumulation above this value. Its heart of palm grows up to 112.5 cm and, above this height, only leaf elongation occurs. It is not recommended to cut this plant bellow 140 cm height, otherwise that can affect the pseudo-stem formation (heart of palm, which supports the leaf biomass accumulation.

IR radiation characteristics of rocket exhaust plumes under varying motor operating conditions

Directory of Open Access Journals (Sweden)

Qinglin NIU

2017-06-01

Full Text Available The infrared (IR irradiance signature from rocket motor exhaust plumes is closely related to motor type, propellant composition, burn time, rocket geometry, chamber parameters and flight conditions. In this paper, an infrared signature analysis tool (IRSAT was developed to understand the spectral characteristics of exhaust plumes in detail. Through a finite volume technique, flow field properties were obtained through the solution of axisymmetric Navier-Stokes equations with the Reynolds-averaged approach. A refined 13-species, 30-reaction chemistry scheme was used for combustion effects and a k-ε-Rt turbulence model for entrainment effects. Using flowfield properties as input data, the spectrum was integrated with a line of sight (LOS method based on a single line group (SLG model with Curtis-Godson approximation. The model correctly predicted spectral distribution in the wavelengths of 1.50–5.50 μm and had good agreement for its location with imaging spectrometer data. The IRSAT was then applied to discuss the effects of three operating conditions on IR signatures: (a afterburning; (b chamber pressure from ignition to cutoff; and (c minor changes in the ratio of hydroxyl-terminated polybutadiene (HTPB binder to ammonium perchlorate (AP oxidizer in propellant. Results show that afterburning effects can increase the size and shape of radiance images with enhancement of radiation intensity up to 40%. Also, the total IR irradiance in different bands can be characterized by a non-dimensional chamber pressure trace in which the maximum discrepancy is less than 13% during ignition and engine cutoff. An increase of chamber pressure can lead to more distinct diamonds, whose distance intervals are extended, and the position of the first diamond moving backwards. In addition, an increase in HTPB/AP causes a significant jump in spectral intensity. The incremental rates of radiance intensity integrated in each band are linear with the increase of HTPB

Influence of culture conditions for clinically isolated non-albicans Candida biofilm formation.

Science.gov (United States)

Tan, Yulong; Leonhard, Matthias; Ma, Su; Schneider-Stickler, Berit

2016-11-01

Non-albicans Candida species have been isolated in increasing numbers in patients. Moreover, they are adept at forming biofilms. This study analyzed biofilm formation of clinically isolated non-albicans Candida, including Candida tropicalis, Candida krusei and Candida parapsilosis under the influence of different growth media (RPMI 1640, YPD and BHI) and several culture variables (inoculum concentration, incubation period and feeding conditions). The results showed that culture conditions strongly influenced non-albicans Candida species biofilm formation. YPD and BHI resulted in larger amount of biofilm formation with higher metabolic activity of biofilms. Furthermore, the growth media seems to have varying effects on adhesion and biofilm development. Growth conditions may also influence biofilm formation, which was enhanced when starting the culture with a larger inoculum, longer incubation period and using a fed-batch system. Therefore, the potential influences of external environmental factors should be considered when studying the non-albicans Candida biofilms in vitro. Copyright © 2016 Elsevier B.V. All rights reserved.

Toxicity of pentachlorophenol to aquatic organisms under naturally varying and controlled environmental conditions

Energy Technology Data Exchange (ETDEWEB)

Hedtke, S.F.; West, C.W.; Allen, K.N.; Norberg-King, T.J.; Mount, D.I.

1986-06-01

The toxicity of pentachlorophenol (PCP) was determined in the laboratory for 11 aquatic species. Tests were conducted seasonally in ambient Mississippi River water and under controlled conditions in Lake Superior water. Fifty-one acute toxicity tests were conducted, with LC50 values ranging from 85 micrograms/L for the white sucker Catastomus commersoni during the summer to greater than 7770 micrograms/L for the isopod Asellus racovitzai during the winter. The effect of PCP on growth and/or reproduction was determined for seven species. The most sensitive chronically exposed organisms were the cladoceran Ceriodaphnia reticulata and the snail Physa gyrina. The greatest variation in toxicity was due to species sensitivity. Within a given, season there was as much as a 40-fold difference in LC50 values between species. For any one species, the maximum variation in LC50 between seasons was approximately 14-fold. There were also substantial differences in acute-chronic relationships, with acute/chronic ratios ranging from greater than 37 for C. reticulata to 1 for Simocephalus vetulus. It is suggested that the composition of the aquatic community should be the most important consideration in estimating the potential environmental effects of PCP.

In vitro conservation of Piper aduncum and Piper hispidinervum under slow-growth conditions

Directory of Open Access Journals (Sweden)

Tatiane Loureiro da Silva

2011-04-01

Full Text Available The objective of this work was to evaluate in vitro storage of Piper aduncum and P. hispidinervum under slow-growth conditions. Shoots were stored at low temperatures (10, 20 and 25°C, and the culture medium was supplemented with osmotic agents (sucrose and mannitol - at 1, 2 and 3% and abiscisic acid - ABA (0, 0.5, 1.0, 2.0 and 3.0 mg L-1. After six-months of storage, shoots were evaluated for survival and regrowth. Low temperature at 20ºC was effective for the in vitro conservation of P. aduncum and P. hispidinervum shoots. In vitro cultures maintained at 20ºC on MS medium showed 100% survival with slow-growth shoots. The presence of mannitol or ABA, in the culture medium, negatively affected shoot growth, which is evidenced by the low rate of recovered shoots.

The effects of intermittent exposure to low pH and oxygen conditions on survival and growth of juvenile red abalone

Science.gov (United States)

Kim, T. W.; Barry, J. P.; Micheli, F.

2013-02-01

Exposure of nearshore animals to hypoxic, low pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low pH and/or low oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5-10 mm). Mortality rates of juvenile abalone exposed to low pH (7.5, total scale) and low O2 (40% saturation, 5 mg L-1) conditions for periods of 3 to 6 h every 3-5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L-1; pH 8.0). However, when exposure was extended to 24 h repeated twice over a 15 day period, juveniles experienced higher mortality in the low oxygen treatments compared to control conditions, regardless of pH levels (pH 7.5 vs. 8.0). Growth rates were reduced significantly when juveniles were exposed to low pH or low oxygen treatments and the growth was lowest when low pH exposure was combined with low O2. Furthermore, individual variation of growth rate increased when they were exposed to low pH and low O2 conditions. These results indicate that prolonged exposure to low oxygen levels is detrimental for the survival of red abalone, whereas both pH and oxygen is a crucial factor for their growth. However, given the higher individual variation in growth rate, they may have an ability to adapt to extended exposure to upwelling conditions.

Evaluation of growth and flowering potential of rosa hybrida cultivars under Faisalabad climatic conditions

International Nuclear Information System (INIS)

Nadeem, M.; Khan, M.A.; Riaz, A.

2011-01-01

Exotic cultivars of hybrid roses respond uncertainly to new habitat. It is necessary to explore the potential of the introduced cultivars to judge the suitability in a new habitat. In the present study, nine Rosa hybrida cultivars including Autumn Sunset, Ice Berg, Paradise, Angel Face, Louise Odier, Casino, Grand Margina, Handel and Gruss-an-Teplitz were evaluated for growth and yield attributed under the climatic conditions of Faisalabad. Results indicated that there was decreasing trend in the growth and flowering of the bushes as the temperature increased above 32 degree C and humidity decreased to 29 %. Number of flowers per bush and diameter of flower decreased as the temperature increased and humidity decreased in contrast to increment in height of the plant and num ber of primary branches per plant in succeeding months. Interaction between yield traits and months was also significant. Overall, significant variations were observed in each cultivar for length and number of petals per flower, number of prickles, fragrance, flower persistence life and color, bush shape and overall performance with respect to climatic conditions of Faisalabad. It is concluded that the cultivars 'Autumn Sunset' and Gruss-an-Teplitz performed better in climatic conditions of Faisalabad. (author)

Modeling the Lag Period and Exponential Growth of Listeria monocytogenes under Conditions of Fluctuating Temperature and Water Activity Values▿

Science.gov (United States)

Muñoz-Cuevas, Marina; Fernández, Pablo S.; George, Susan; Pin, Carmen

2010-01-01

The dynamic model for the growth of a bacterial population described by Baranyi and Roberts (J. Baranyi and T. A. Roberts, Int. J. Food Microbiol. 23:277-294, 1994) was applied to model the lag period and exponential growth of Listeria monocytogenes under conditions of fluctuating temperature and water activity (aw) values. To model the duration of the lag phase, the dependence of the parameter h0, which quantifies the amount of work done during the lag period, on the previous and current environmental conditions was determined experimentally. This parameter depended not only on the magnitude of the change between the previous and current environmental conditions but also on the current growth conditions. In an exponentially growing population, any change in the environment requiring a certain amount of work to adapt to the new conditions initiated a lag period that lasted until that work was finished. Observations for several scenarios in which exponential growth was halted by a sudden change in the temperature and/or aw were in good agreement with predictions. When a population already in a lag period was subjected to environmental fluctuations, the system was reset with a new lag phase. The work to be done during the new lag phase was estimated to be the workload due to the environmental change plus the unfinished workload from the uncompleted previous lag phase. PMID:20208022

Modeling the lag period and exponential growth of Listeria monocytogenes under conditions of fluctuating temperature and water activity values.

Science.gov (United States)

Muñoz-Cuevas, Marina; Fernández, Pablo S; George, Susan; Pin, Carmen

2010-05-01

The dynamic model for the growth of a bacterial population described by Baranyi and Roberts (J. Baranyi and T. A. Roberts, Int. J. Food Microbiol. 23:277-294, 1994) was applied to model the lag period and exponential growth of Listeria monocytogenes under conditions of fluctuating temperature and water activity (a(w)) values. To model the duration of the lag phase, the dependence of the parameter h(0), which quantifies the amount of work done during the lag period, on the previous and current environmental conditions was determined experimentally. This parameter depended not only on the magnitude of the change between the previous and current environmental conditions but also on the current growth conditions. In an exponentially growing population, any change in the environment requiring a certain amount of work to adapt to the new conditions initiated a lag period that lasted until that work was finished. Observations for several scenarios in which exponential growth was halted by a sudden change in the temperature and/or a(w) were in good agreement with predictions. When a population already in a lag period was subjected to environmental fluctuations, the system was reset with a new lag phase. The work to be done during the new lag phase was estimated to be the workload due to the environmental change plus the unfinished workload from the uncompleted previous lag phase.

Selecting Native Arbuscular Mycorrhizal Fungi to Promote Cassava Growth and Increase Yield under Field Conditions

Science.gov (United States)

Séry, D. Jean-Marc; Kouadjo, Z. G. Claude; Voko, B. R. Rodrigue; Zézé, Adolphe

2016-01-01

The use of arbuscular mycorrhizal fungal (AMF) inoculation in sustainable agriculture is now widespread worldwide. Although the use of inoculants consisting of native AMF is highly recommended as an alternative to commercial ones, there is no strategy to allow the selection of efficient fungal species from natural communities. The objective of this study was (i) to select efficient native AMF species (ii) evaluate their impact on nematode and water stresses, and (iii) evaluate their impact on cassava yield, an important food security crop in tropical and subtropical regions. Firstly, native AMF communities associated with cassava rhizospheres in fields were collected from different areas and 7 AMF species were selected, based upon their ubiquity and abundance. Using these criteria, two morphotypes (LBVM01 and LBVM02) out of the seven AMF species selected were persistently dominant when cassava was used as a trap plant. LBVM01 and LBVM02 were identified as Acaulospora colombiana (most abundant) and Ambispora appendicula, respectively, after phylogenetic analyses of LSU-ITS-SSU PCR amplified products. Secondly, the potential of these two native AMF species to promote growth and enhance tolerance to root-knot nematode and water stresses of cassava (Yavo variety) was evaluated using single and dual inoculation in greenhouse conditions. Of the two AMF species, it was shown that A. colombiana significantly improved the growth of the cassava and enhanced tolerance to water stress. However, both A. colombiana and A. appendicula conferred bioprotective effects to cassava plants against the nematode Meloidogyne spp., ranging from resistance (suppression or reduction of the nematode reproduction) or tolerance (low or no suppression in cassava growth). Thirdly, the potential of these selected native AMF to improve cassava growth and yield was evaluated under field conditions, compared to a commercial inoculant. In these conditions, the A. colombiana single inoculation and the

Increased biomass yield of Lactococcus lactis during energetically limited growth and respiratory conditions

DEFF Research Database (Denmark)

Købmann, Brian Jensen; Blank, Lars Mathias; Solem, Christian

2008-01-01

(glucose/mannose-specific phosphotransferase system). Amino acid catabolism could be excluded as the source of the additional ATP. Since mutants without a functional H+-ATPase produced less ATP under sugar starvation and respiratory conditions, the additional ATP yield appears to come partly from energy......Lactococcus lactis is known to be capable of respiration under aerobic conditions in the presence of haemin. In the present study the effect of respiration on ATP production during growth on different sugars was examined. With glucose as the sole carbon source, respiratory conditions in L. lactis...... MG1363 resulted in only a minor increase, 21%, in biomass yield. Since ATP production through substrate-level phosphorylation was essentially identical with and without respiration, the increased biomass yield was a result of energy-saving under respiratory conditions estimated to be 0.4 mol of ATP...

Growth and yield of different brassica genotypes under saline sodic conditions

International Nuclear Information System (INIS)

Ali, A.; Mahmood, I.A.; Salim, M.

2013-01-01

A field study was conducted at farmer's salt-affected field (ECe=12.3 dS m/sup -1/; pH=9.7; SAR=46.2) in Hafizabad to test growth and yield response of six Brassica cultivars (BARD-I, Dunkled, Rainbow, BRS-II, Sultan Raya and cv. 95102-5) under saline sodic conditions. Data on growth and yield parameters were collected randomly (average of five plants per replication) at the time of crop maturity. Ionic concentration in plant tissues and oil content in seeds were also determined. Comparatively more number of branches and pods per plant were produced by cultivar Dunkled closely followed by BARD-I while maximum seed yield (241.7 and 235.1 kg ha ) was obtained from Dunkled and Sultan Raya, respectively which was statistically at par. However, BRS-II and Rainbow showed significantly more percent oil contents in their seeds but genotype Dunkled showed minimum Na+ and K+ concentration in their tissues. (author)

Positive impact of bio-stimulators on growth and physiological activity of willow in climate change conditions

Science.gov (United States)

Piotrowski, Krzysztof; Romanowska-Duda, Zdzisława

2018-04-01

The aim of this research was to evaluate the physiological activity and growth of willow (Salix viminalis L.) plants cultivated under the conditions of adverse temperature and soil moisture content, and to assess the effect of the foliar application of Biojodis (1.0%) and Asahi SL (0.03%) bio-stimulators, or a mixture of Microcistis aeruginosa MKR 0105 and Anabaena PCC 7120 cyanobacteria under such changing growth conditions. The obtained results showed different reactions to the applied constant or periodically changed temperature and soil moisture content. The plants which grew at periodically changed adverse temperature (from -5 to 40oC) or in scantily (20% m.c.) or excessively (60% m.c.) watered soils, grew slowly, in comparison with those growing at 20oC and in optimally moistened soil (30% m.c.). Foliar application of Biojodis and Asahi SL cyanobacteria increased the growth of willow at optimal and adverse temperature or in scantily and excessively moistened soil. The changes in plant growth were associated with the changes in electrolyte leakage, activity of acid or alkaline phosphatases, RNase, index of chlorophyll content in leaves and gas exchange. The above indicates that the foliar application of the studied cyanobacteria and bio-stimulators partly alleviates the harmful impact of adverse temperature and water stress on growth and physiological activity of willow plants

Resource investments in reproductive growth proportionately limit investments in whole-tree vegetative growth in young olive trees with varying crop loads.

Science.gov (United States)

Rosati, Adolfo; Paoletti, Andrea; Al Hariri, Raeed; Morelli, Alessio; Famiani, Franco

2018-02-21

It has long been debated whether tree growth is source limited, or whether photosynthesis is adjusted to the actual sink demand, directly regulated by internal and environmental factors. Many studies support both possibilities, but no studies have provided quantitative data at the whole-tree level, across different cultivars and fruit load treatments. This study investigated the effect of different levels of reproductive growth on whole-tree biomass growth across two olive cultivars with different growth rates (i.e., Arbequina, slow-growing and Frantoio, fast-growing), over 2 years. Young trees of both cultivars were completely deflowered either in 2014, 2015, both years or never, providing a range of levels of cumulated reproductive growth over the 2 years. Total vegetative dry matter growth over the 2 years was assessed by destructive sampling (whole tree). Vegetative growth increased significantly less in fruiting trees, however, the total of vegetative and reproductive growth did not differ significantly for any treatment or cultivar. Vegetative growth over the 2 years was closely (R2 = 0.89) and inversely related to reproductive growth across all treatments and cultivars. When using data from 2015 only, the regression improved further (i.e., R2 = 0.99). When biomass was converted into grams of glucose equivalents, based on the chemical composition of the different parts, the results indicated that for every gram of glucose equivalent invested in reproductive growth, vegetative growth was reduced by 0.73-0.78 g of glucose equivalent. This indicates that competition for resources played a major role in determining tree growth, but also that photosynthesis was probably also enhanced at increasing fruit load (or downregulated at decreasing fruit load). The leaf area per unit of trunk cross sectional area increased with deflowering (i.e., decreased with reproductive growth), suggesting that water relations might have limited photosynthesis in deflowered plants

The Escherichia coli transcriptome linked to growth fitness

Directory of Open Access Journals (Sweden)

Bei-Wen Ying

2016-03-01

Full Text Available A series of Escherichia coli strains with varied genomic sequences were subjected to high-density microarray analyses to elucidate the fitness-correlated transcriptomes. Fitness, which is commonly evaluated by the growth rate during the exponential phase, is not only determined by the genome but is also linked to growth conditions, e.g., temperature. We previously reported genetic and environmental contributions to E. coli transcriptomes and evolutionary transcriptome changes in thermal adaptation. Here, we describe experimental details on how to prepare microarray samples that truly represent the growth fitness of the E. coli cells. A step-by-step record of sample preparation procedures that correspond to growing cells and transcriptome data sets that are deposited at the GEO database (GSE33212, GSE52770, GSE61739 are also provided for reference. Keywords: Transcriptome, Growth fitness, Escherichia coli, Microarray

Effects of sires with different weight gain potentials and varying planes of nutrition on growth of growing-finishing pigs.

Science.gov (United States)

Ha, Duck-Min; Jung, Dae-Yun; Park, Man Jong; Park, Byung-Chul; Lee, C Young

2014-01-01

The present study was performed to investigate the effects of two groups of sires with 'medium' and 'high' weight gain potentials (M-sires and H-sires, respectively) on growth of their progenies on varying planes of nutrition during the growing-finishing period. The ADG of the M-sires' progeny was greater (P plane of nutrition (H plane) followed by the medium (M) and low (L) planes (0.65, 0.61, and 0.51 kg, respectively; P planes vs. L plane (0.63, 0.62, and 0.54 kg, respectively). The ADG of pigs on the M or H plane during the grower phase and switched to the H plane thereafter (M-to-H or H-to-H planes) was greater than that of pigs on the L-to-L planes (0.99 vs. 0.78 kg) during the early finisher phase in the M-sires' progeny (P planes did not differ from that of pigs on the M-to-M or H-to-M planes (0.94 vs. 0.96 kg). Results suggest that the H-to-H or H-to-M planes and M-to-M or M-to-L planes are optimal for maximal growth of the M- and H-sires' progenies, respectively.

Growth of Corophium volutator under laboratory conditions

NARCIS (Netherlands)

Kater, B.J.; Jol, J.G.; Smit, M.G.D.

2008-01-01

Temperature-dependent growth is an important factor in the population model of Corophium volutator that was developed to translate responses in a 10-day acute bioassay to ecological consequences for the population. The growth rate, however, was estimated from old data, based on a Swedish population.

Initial growth of Costus longebracteolatus and Costus spiralis ‘French Kiss’ under different light conditions

Directory of Open Access Journals (Sweden)

Renata Bachin Mazzini-Guedes

2016-12-01

Full Text Available The Brazilian native Costus longebracteolatus and Costus spiralis ‘French Kiss’, in the family Costaceae, have been used as both cut flowers and cut foliage. It is known that Costus species grow better under partial shade, but studies on the influence of shading or light on plant growth, development, and flower production are still incipient. As this kind of information is essential on planning of planting, production, and agribusiness activities, the objective of this research was to evaluate the influence of different colored shade nets and light conditions on the initial growth of both C. longebracteolatus and C. spiralis ‘French Kiss’. Plants, obtained from cuttings of pseudostems, were cultivated under six light conditions, which comprised six treatments, along 270 days: red net with 50% shading, blue net with 50% shading, black net with 70% shading, black net with 50% shading, black net with 30% shading, and full sun. The initial growth of C. longebracteolatus (up to 270 days is more successful under the blue net with 50% shading, which promoted highest values of pseudostem length and dry matter of aerial part. For C. spiralis ‘French Kiss’ plants, both the red and blue nets with 50% shading implied best results and differed for the other treatments with greater pseudostem length. Plant exposure to full sun inhibited growth and development, and favored early leaf necrosis.

Growth patterns and annual growth cycle of Acacia karroo Hayne in ...

African Journals Online (AJOL)

... karroo; alice; botany; compensatory growth; condition; development; eastern cape; emergence; environmental conditions; field study; growth cycle; growth initiation; growth patterns; growth strategy; leaf growth; plant growth; savanna; shoot growth; soil depth; soil moisture; south africa; university of fort hare; water stress ...

Conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans: influence of growth conditions and antifungal susceptibility profiles

Directory of Open Access Journals (Sweden)

Thaís Pereira de Mello

2016-01-01

Full Text Available In the present study, we have investigated some growth conditions capable of inducing the conidial germination in Scedosporium apiospermum, S. aurantiacum, S. minutisporum and Lomentospora prolificans. Germination in Sabouraud medium (pH 7.0, 37ºC, 5% CO2 showed to be a typically time-dependent event, reaching ~75% in S. minutisporum and > 90% in S. apiospermum, S. aurantiacum and L. prolificans after 4 h. Similar germination rate was observed when conidia were incubated under different media and pHs. Contrarily, temperature and CO2 tension modulated the germination. The isotropic conidial growth (swelling and germ tube-like projection were evidenced by microscopy and cytometry. Morphometric parameters augmented in a time-dependent fashion, evidencing changes in size and granularity of fungal cells compared with dormant 0 h conidia. In parallel, a clear increase in the mitochondrial activity was measured during the transformation of conidia-into-germinated conidia. Susceptibility profiles to itraconazole, fluconazole, voriconazole, amphotericin B and caspofungin varied regarding each morphotype and each fungal species. Overall, the minimal inhibitory concentrations for hyphae were higher than conidia and germinated conidia, except for caspofungin. Collectively, our study add new data about the conidia-into-hyphae transformation in Scedosporium and Lomentospora species, which is a relevant biological process of these molds directly connected to their antifungal resistance and pathogenicity mechanisms.

Uniform shrub growth response to June temperature across the North Slope of Alaska

Science.gov (United States)

Ackerman, Daniel E.; Griffin, Daniel; Hobbie, Sarah E.; Popham, Kelly; Jones, Erin; Finlay, Jacques C.

2018-04-01

The expansion of woody shrubs in arctic tundra alters many aspects of high-latitude ecosystems, including carbon cycling and wildlife habitat. Dendroecology, the study of annual growth increments in woody plants, has shown promise in revealing how climate and environmental conditions interact with shrub growth to affect these key ecosystem properties. However, a predictive understanding of how shrub growth response to climate varies across the heterogeneous landscape remains elusive. Here we use individual-based mixed effects modeling to analyze 19 624 annual growth ring measurements in the stems of Salix pulchra (Cham.), a rapidly expanding deciduous shrub. Stem samples were collected at six sites throughout the North Slope of Alaska. Sites spanned four landscapes that varied in time since glaciation and hence in soil properties, such as nutrient availability, that we expected would modulate shrub growth response to climate. Ring growth was remarkably coherent among sites and responded positively to mean June temperature. The strength of this climate response varied slightly among glacial landscapes, but in contrast to expectations, this variability was not systematically correlated with landscape age. Additionally, shrubs at all sites exhibited diminishing marginal growth gains in response to increasing temperatures, indicative of alternative growth limiting mechanisms in particularly warm years, such as temperature-induced moisture limitation. Our results reveal a regionally-coherent and robust shrub growth response to early season growing temperature, with local soil properties contributing only a minor influence on shrub growth. Our conclusions strengthen predictions of changes to wildlife habitat and improve the representation of tundra vegetation dynamics in earth systems models in response to future arctic warming.

Phytoremdiation Species And Their Modification Under By Weed Varying Climatic Condition A Changing Scenario

Directory of Open Access Journals (Sweden)

Anita Singh

2015-08-01

Full Text Available Abstract The major reasons for environmental contamination are population explosion increase in industrial and other urban activities. One of the consequent effect of these activities is heavy metal pollution. It is one of the serious issue to be discussed by the scientists and academicians that how to solve this problem to protect the environment. As heavy metals are non-biodegradable so they require effective cleanup technology. Most of the traditional methods such as excavation solidification and burial are very costly or they simply involve the isolation of the metals from contaminated sites. Among different technologies phytoremediation is best approach for removing metal contamination from environment. It involves plants to remove detoxify or immobilize metals from environment. Weed plants are found to be play very important role in metal remediation. They get affected by climatic variation which is also a consequent effect of environmental pollution. The physiology of plants as well as physiochemical properties of soil gets affected by varying climatic condition. Therefore the present review gives the information on metal remediation processes and how these process particularly phytoremediation by weed plants get affected by climatic changes.

Growth Responses of Fish During Chronic Exposure of Metal Mixture under Laboratory Conditions

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Saima Naz and Muhammad Javed

2013-07-01

Full Text Available Growth responses of five fish species viz. Catla catla, Labeo rohita, Cirrhina mrigala, Ctenopharyngodon idella and Hypophthalmichthys molitrix were determined, separately, under chronic exposure of binary mixture of metals (Zn+Ni at sub-lethal concentrations (1/3rd of LC50 for 12 weeks. Randomized complete block design (RCBD was followed to conduct this research work. The groups (10 fish each of Catla catla, Labeo rohita, Cirrhina mrigala, Ctenopharyngodon idella and Hypophthalmichthys molitrix having almost similar weights were investigated for their growth responses and metals bioaccumulation patterns in their body organs during chronic exposure of Zn+Ni mixture. The bioaccumulation of metals in the fish body organs viz. gills, liver, kidney, fins, bones, muscle and skin were also determined before and after growth trails under the stress of metals mixture. The exposure of fish to sub-lethal concentrations of mixture caused significant impacts on the average wet weight increments of five fish species. Ctenopharyngodon idella and Labeo rohita attained significantly higher weights, followed by that of Hypophthalmichthys molitrix, Cirrhina mrigala and Catla catla. However, the growth of metals mixture exposed fish species was significantly lesser than that of control fish (un-stressed. Significantly variable condition factor values reflected the degree of fish well-beings that correlated directly with fish growth and metal exposure concentration. Any significant change in feed intake, due to stress, is reflected in terms of fish growth showing the impacts of metal mixture on fish growth were either additive or antagonist / synergistic. Accumulation of all the metals in fish body followed the general order: liver>kidney>gills> skin >muscle> fins >bones.

Response of an algal consortium to diesel under varying culture conditions.

Science.gov (United States)

Chavan, Anal; Mukherji, Suparna

2010-03-01

A diesel-tolerant sessile freshwater algal consortium obtained from the vicinity of Powai Lake (Mumbai, India) was cultured in the laboratory. The presence of diesel in batch cultures enhanced the maximum specific growth rate of the algal consortium. With decrease in light-dark (L:D) cycle from 20:4 to 4:20 h, the chlorophyll-a levels decreased; however, the removal of diesel was found to be maximum at L:D of 18:6 h with 37.6% degradation over and above controls. In addition to growth in the form of green clumps, white floating biomass was found surrounding the diesel droplets on the surface. This culture predominated at the least L:D ratio of 4:20 h. Studies confirmed the ability of the floating organisms to grow heterotrophically in the dark utilizing diesel as carbon source and also in the presence of light in a medium devoid of organic carbon sources.

The relative importance of intrinsic and extrinsic drivers to population growth vary among local populations of Greater Sage-Grouse: An integrated population modeling approach

Science.gov (United States)

Coates, Peter S.; Prochazka, Brian G.; Ricca, Mark A.; Halstead, Brian J.; Casazza, Michael L.; Blomberg, Erik J.; Brussee, Brianne E.; Wiechman, Lief; Tebbenkamp, Joel; Gardner, Scott C.; Reese, Kerry P.

2018-01-01

Consideration of ecological scale is fundamental to understanding and managing avian population growth and decline. Empirically driven models for population dynamics and demographic processes across multiple spatial scales can be powerful tools to help guide conservation actions. Integrated population models (IPMs) provide a framework for better parameter estimation by unifying multiple sources of data (e.g., count and demographic data). Hierarchical structure within such models that include random effects allow for varying degrees of data sharing across different spatiotemporal scales. We developed an IPM to investigate Greater Sage-Grouse (Centrocercus urophasianus) on the border of California and Nevada, known as the Bi-State Distinct Population Segment. Our analysis integrated 13 years of lek count data (n > 2,000) and intensive telemetry (VHF and GPS; n > 350 individuals) data across 6 subpopulations. Specifically, we identified the most parsimonious models among varying random effects and density-dependent terms for each population vital rate (e.g., nest survival). Using a joint likelihood process, we integrated the lek count data with the demographic models to estimate apparent abundance and refine vital rate parameter estimates. To investigate effects of climatic conditions, we extended the model to fit a precipitation covariate for instantaneous rate of change (r). At a metapopulation extent (i.e. Bi-State), annual population rate of change λ (er) did not favor an overall increasing or decreasing trend through the time series. However, annual changes in λ were driven by changes in precipitation (one-year lag effect). At subpopulation extents, we identified substantial variation in λ and demographic rates. One subpopulation clearly decoupled from the trend at the metapopulation extent and exhibited relatively high risk of extinction as a result of low egg fertility. These findings can inform localized, targeted management actions for specific areas

Feeding behaviour and growth of the Peruvian scallop (Argopecten purpuratus) under daily cyclic hypoxia conditions

Science.gov (United States)

Aguirre-Velarde, Arturo; Jean, Fred; Thouzeau, Gérard; Flye-Sainte-Marie, Jonathan

2018-01-01

As a secondary consequence of the high productivity of the upwelling system, organisms inhabiting Peruvian coastal bays are frequently exposed to hypoxic conditions. The aim of the present paper was to investigate the effects of daily-cyclic-severe hypoxia on energetics of a species presenting little escape ability when facing hypoxia. For this purpose, juvenile Peruvian scallops (Argopecten purpuratus) were exposed to four experimental conditions: fed and starved, combined or not to nightly severe hypoxia (5% oxygen saturation) for ≈ 12 h over a 21-day experiment. In both fed conditions, clearance rate was measured by the mean of an open-flow system. Our results indicate that the Peruvian scallop is able to maintain an active filtration even at low oxygen saturation, at least during expositions up to 12 h. During the first phase of exposure to hypoxia, clearance rate decreased abruptly when oxygen saturation dropped below 10%, but rapidly recovered to values close to those found under normoxia. As a consequence of this ability to feed during hypoxia, no difference in soft tissue dry weight (digestive gland not included) was observed at the end of the experimental period between oxic conditions among fed scallops. However, shell growth was negatively affected by hypoxic condition. Starved individuals exhibited similar weight loss between hypoxic and normoxic conditions indicating no or little effect of oxic condition on maintenance costs. Considering the observed responses for feeding, growth and maintenance, we can hypothesize that this species presents metabolic/bioenergetic efficient adaptations to deal with hypoxic conditions that are recurrent in Peruvian coastal bays. We hypothesize that the small observed effects might be modelled in the context of the Dynamic Energy Budget theory as a restriction of reserve mobilization under hypoxic conditions.

Housing conditions affecting interior moisture levels: links to mould growth and children's respiratory health

Energy Technology Data Exchange (ETDEWEB)

Wells, John A. [Crosier Kilgour and Partners Ltd. (Canada)], email: john.w@ckpeng.com; Polyzois, Dimos [Department of Civil Engineering, University of Manitoba (Canada)], email: polyzoi@cc.umanitoba.ca; Polyzoi, Eleoussa [Faculty of Education, University of Winnipeg (Canada)], email: l.polyzoi@uwinnipeg.ca

2011-07-01

Previous research has demonstrated that a person's respiratory health is affected by high indoor moisture content in their house. The aim of this paper is to provide a better understanding of the link between housing conditions and respiratory health, so that strategies can be implemented to improve the quality of life of children. This study was carried out through the completion of a survey by 3,423 parents in Winnipeg, Canada, the collection of 715 air samples from the residences of 715 parents, and an engineering audit of their homes. This study showed that a strong relationship exists between building moisture content and common home maintenance and that routine maintenance is efficient in significantly reducing the growth of mould which impacts children's respiratory health. This paper provided useful information on the relation between housing conditions and respiratory health problems and the rest of the study will aim at determining which building conditions impact mould growth most.

Conditional expression of constitutively active estrogen receptor {alpha} in chondrocytes impairs longitudinal bone growth in mice

Energy Technology Data Exchange (ETDEWEB)

Ikeda, Kazuhiro [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Tsukui, Tohru [Experimental Animal Laboratory, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Imazawa, Yukiko; Horie-Inoue, Kuniko [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Inoue, Satoshi, E-mail: INOUE-GER@h.u-tokyo.ac.jp [Division of Gene Regulation and Signal Transduction, Research Center for Genomic Medicine, Saitama Medical University, Saitama (Japan); Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan); Department of Anti-Aging Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan)

2012-09-07

Highlights: Black-Right-Pointing-Pointer Conditional transgenic mice expressing constitutively active estrogen receptor {alpha} (caER{alpha}) in chondrocytes were developed. Black-Right-Pointing-Pointer Expression of caER{alpha} in chondrocytes impaired longitudinal bone growth in mice. Black-Right-Pointing-Pointer caER{alpha} affects chondrocyte proliferation and differentiation. Black-Right-Pointing-Pointer This mouse model is useful for understanding the physiological role of ER{alpha}in vivo. -- Abstract: Estrogen plays important roles in the regulation of chondrocyte proliferation and differentiation, which are essential steps for longitudinal bone growth; however, the mechanisms of estrogen action on chondrocytes have not been fully elucidated. In the present study, we generated conditional transgenic mice, designated as caER{alpha}{sup ColII}, expressing constitutively active mutant estrogen receptor (ER) {alpha} in chondrocytes, using the chondrocyte-specific type II collagen promoter-driven Cre transgenic mice. caER{alpha}{sup ColII} mice showed retardation in longitudinal growth, with short bone lengths. BrdU labeling showed reduced proliferation of hypertrophic chondrocytes in the proliferating layer of the growth plate of tibia in caER{alpha}{sup ColII} mice. In situ hybridization analysis of type X collagen revealed that the maturation of hypertrophic chondrocytes was impaired in caER{alpha}{sup ColII} mice. These results suggest that ER{alpha} is a critical regulator of chondrocyte proliferation and maturation during skeletal development, mediating longitudinal bone growth in vivo.

Panorama 2011: Refining: varying conditions by region

International Nuclear Information System (INIS)

Silva, C.

2011-01-01

The economic crisis has further weakened a sector that was already facing difficulties, if we look beyond the flush period (2005-2008) when, buoyed by strong demand, margins remained high and refiners could generate profits while maintaining a healthy level of activity. Falling demand and increased over-capacity in some regions - the immediate consequences of the deteriorating economic conditions over the past two years - have led to declining margins and to financial accounts being in the red. The adoption of increasingly stringent emissions standards and product specifications, burdensome regulatory requirements for refineries (for combating local pollution and reducing greenhouse gas emissions), stiffer competition from new fuels: all of these structural factors are weakening the sector, especially in industrialized nations with their more rigorous regulatory compliance. In this generally gloomy climate, numerous new projects are still being envisaged - although many have recently been postponed and tend to be concentrated in developing countries. (author)

Growth, Toxin Production and Allelopathic Effects of Pseudo-nitzschia multiseries under Iron-Enriched Conditions

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Bruna Fernanda Sobrinho

2017-10-01

Full Text Available In order to assess the effects of Fe-enrichment on the growth and domoic acid (DA production of the toxigenic diatom Pseudo-nitzschia multiseries, static cultures that received the addition of different iron (Fe concentrations were maintained for 30 days. Intra- and extracellular DA concentrations were evaluated over time, and growth and chain-formation were compared to those of non-toxic diatoms, Bacillaria sp. Growth rates of P. multiseries (μ = 0.45–0.73 d−1 were similar among cultures containing different Fe concentrations. Likewise, the similar incidence and length of P. multiseries stepped cell chains (usually 2–4; up to 8-cell long among the treatments reinforces that the cultures were not growth-inhibited under any condition tested, suggesting an efficient Fe acquisition mechanism. Moreover, DA concentrations were significantly higher under the highest Fe concentration, indicating that Fe is required for toxin synthesis. Bacillaria sp. reached comparable growth rates under the same Fe concentrations, except when the dissolved cell contents from a P. multiseries culture was added. The 50–70% reduction in cell density and 70–90% decrease in total chlorophyll-a content of Bacillaria sp. at early stationary growth phase indicates, for the first time, an allelopathic effect of undetermined compounds released by Pseudo-nitzschia to another diatom species.

Bacillus amyloliquefaciens L-S60 Reforms the Rhizosphere Bacterial Community and Improves Growth Conditions in Cucumber Plug Seedling

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Yuxuan Qin

2017-12-01

Full Text Available Vegetable plug seedling has become the most important way to produce vegetable seedlings in China. This seedling method can significantly improve the quality and yield of vegetables compared to conventional methods. In the process of plug seedling, chemical fertilizers or pesticides are often used to improve the yield of the seedlings albeit with increasing concerns. Meanwhile, little is known about the impact of beneficial bacteria on the rhizosphere microbiota and the growth conditions of vegetables during plug seedling. In this study, we applied a culture-independent next-generation sequencing-based approach and investigated the impact of a plant beneficial bacterium, Bacillus amyloliquefaciens L-S60, on the composition and dynamics of rhizosphere microbiota and the growth conditions of cucumbers during plug seedling. Our results showed that application of L-S60 significantly altered the structure of the bacterial community associated with the cucumber seedling; presence of beneficial rhizosphere species such as Bacillus, Rhodanobacter, Paenibacillus, Pseudomonas, Nonomuraea, and Agrobacterium was higher upon L-S60 treatment than in the control group. We also measured the impact of L-S60 application on the physiological properties of the cucumber seedlings as well as the availability of main mineral elements in the seedling at different time points during the plug seedling. Results from those measurements indicated that L-S60 application promoted growth conditions of cucumber seedlings and that more available mineral elements were detected in the cucumber seedlings from the L-S60 treated group than from the control group. The findings in this study provided evidence for the beneficial effects of plant growth-promoting rhizosphere bacteria on the bacterial community composition and growth conditions of the vegetables during plug seedling.

Varied growth response of cogongrass ecotypes to elevated CO2

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G. Brett Runion

2016-01-01

Full Text Available Cogongrass [Imperata cylindrica (L. P. Beauv] is an invasive C4 perennial grass which is listed as one of the top ten worst weeds in the world and is a major problem in the Southeast US. Five cogongrass ecotypes (Florida, Hybrid, Louisiana, Mobile, and North Alabama collected across the Southeast and a red-tip ornamental variety were container grown for six months in open top chambers under ambient and elevated (ambient plus 200 ppm atmospheric CO2. Elevated CO2 increased average dry weight (13% which is typical for grasses. Elevated CO2 increased height growth and both nitrogen and water use efficiencies, but lowered tissue nitrogen concentration; again, these are typical plant responses to elevated CO2. The hybrid ecotype tended to exhibit the greatest growth (followed by Louisiana, North Alabama, and Florida ecotypes while the red-tip and Mobile ecotypes were smallest. Interactions of CO2 with ecotype generally showed that the hybrid, Louisiana, Florida, and/or North Alabama ecotypes showed a positive response to CO2 while the Mobile and red-tip ecotypes did not. Cogongrass is a problematic invasive weed in the southeastern U.S. and some ecotypes may become more so as atmospheric CO2 continues to rise.

The effects of intermittent exposure to low-pH and low-oxygen conditions on survival and growth of juvenile red abalone

Science.gov (United States)

Kim, T. W.; Barry, J. P.; Micheli, F.

2013-11-01

Exposure of nearshore animals to hypoxic, low-pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low-pH and/or low-oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5-10 mm). Mortality rates of juvenile abalone exposed to low-pH (7.5, total scale) and low-O2 (40% saturation, mg L-1) conditions for periods of 3 to 6 h every 3-5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L-1; pH 8.0). However, when exposure was extended to 24 h, twice over a 15-day period, juveniles experienced 5-20% higher mortality in the low-oxygen treatments compared to control conditions. Growth rates were reduced significantly when juveniles were exposed to low-oxygen and low-pH treatments. Furthermore, individual variation of growth rate increased when juveniles were exposed simultaneously to low-pH and low-O2 conditions. These results indicate that prolonged exposure to low-oxygen levels is detrimental for the survival of red abalone, whereas pH is a crucial factor for their growth. However, the high individual variation in growth rate under low levels of both pH and oxygen suggests that cryptic phenotypic plasticity may promote resistance to prolonged upwelling conditions by a portion of the population.

Effect of two plant growth regulators and illumination conditions in the germination of conserved seeds of Clitoria ternatea

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Maribel Quintana

2013-04-01

Full Text Available The seeds viability lost in the seed legume bank of Research Institute of Pastures and Forages (IIPF led to the aim of the work it was to determine the effect of two plant growth regulators (gibberellic acid; GA3 and naphthalene acetic acid; ANA and illumination conditions on the germination of Clitoria ternatea SC-136 conserved seeds. One experiment was performed with two-factor completely randomized design with four replications Five different levels of growth regulators (factor A and two illumination conditions (factor B were evaluated. The variables measured were: total germination percentage (PTG and angular transformation, days to 50% PTG (G50 and the days between 10 and 90% PTG (G10-90. In addition, morphological variables were evaluated. It was found that the addition of plant growth regulators (GA3 and NAA was effective in increasing germination of Clitoria ternatea SC-136 conserved seeds, but not the illumination conditions tested. Combination GA3 (1 mg l-1 and NAA (0.1 mg l-1 to stimulate germination was recommended. Key words: GA3, germplasm, legume, NAA, photoperiod.

Controlled growth of CNT in mesoporous AAO through optimized conditions for membrane preparation and CVD operation

Energy Technology Data Exchange (ETDEWEB)

Ciambelli, P; Sarno, M; Leone, C; Sannino, D [Department of Chemical and Food Engineering, University of Salerno, I-84084 Fisciano (Italy); Arurault, L; Fontorbes, S; Datas, L; Lenormand, P; Le Blond Du Plouy, S, E-mail: msarno@unisa.it, E-mail: arurault@chimie.ups-tlse.fr [Universite de Toulouse, CIRIMAT, UPS/INPT/CNRS, LCMIE, F-31062 Toulouse Cedex 9 (France)

2011-07-01

Anodic aluminium oxide (RAAO) membranes with a mesoporous structure were prepared under strictly controlling experimental process conditions, and physically and chemically characterized by a wide range of experimental techniques. Commercial anodic aluminium oxide (CAAO) membranes were also investigated for comparison. We demonstrated that RAAO membranes have lower content of both water and phosphorus and showed better porosity shape than CAAO. The RAAO membranes were used for template growth of carbon nanotubes (CNT) inside its pores by ethylene chemical vapour deposition (CVD) in the absence of a catalyst. A composite material, containing one nanotube for each channel, having the same length as the membrane thickness and an external diameter close to the diameter of the membrane holes, was obtained. Yield, selectivity and quality of CNTs in terms of diameter, length and arrangement (i.e. number of tubes for each channel) were optimized by investigating the effect of changing the experimental conditions for the CVD process. We showed that upon thermal treatment RAAO membranes were made up of crystallized allotropic alumina phases, which govern the subsequent CNT growth, because of their catalytic activity, likely due to their Lewis acidity. The strict control of experimental conditions for membrane preparation and CNT growth allowed us to enhance the carbon structural order, which is a critical requisite for CNT application as a substitute for copper in novel nano-interconnects.

Propagule pressure, habitat conditions and clonal integration influence the establishment and growth of an invasive clonal plant, Alternanthera philoxeroides

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Wen-Hua eYou

2016-05-01

Full Text Available Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules may affect the establishment, growth and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments or low (one fragment propagule pressure was established either in bare soil (open habitat or dense native vegetation of Jussiaea repens (vegetative habitat, with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions.

Pulsed growth of fungal hyphal tips.

Science.gov (United States)

López-Franco, R; Bartnicki-Garcia, S; Bracker, C E

1994-12-06

Somatic fungal hyphae are generally assumed to elongate at steady linear rates when grown under constant environmental conditions with ample nutrients. However, patterns of pulsed hyphal elongation were detected during apparent steady growth of hyphal tips in fungi from several major taxonomic groups (Oomycetes, Pythium aphanidermatum and Saprolegnia ferax; Zygomycetes, Gilbertella persicaria; Deuteromycetes, Trichoderma viride; Ascomycetes, Neurospora crassa and Fusarium culmorum; Basidiomycetes, Rhizoctonia solani). Growing hyphal tips were recorded with video-enhanced phase-contrast microscopy at high magnification, and digital images were measured at very short time intervals (1-5 s). In all fungi tested, the hyphal elongation rate was never perfectly steady but fluctuated continuously with alternating periods of fast and slow growth at more or less regular intervals. Pulsed growth was observed in fungi differing in cell diameter, overall growth rate, taxonomic position, and presence and pattern of Spitzenkörper organization, suggesting that this is a general phenomenon. Frequency and amplitude of the pulses varied among the test organisms. T. viride and N. crassa showed the most frequent pulses (average of 13-14 per min), and F. culmorum the least frequent (2.7 per min). Average pulse amplitude varied from 0.012 microns/s for F. culmorum to 0.068 microns/s for G. persicaria. In F. culmorum and T. viride, the fast phase of the growth pulses was correlated with the merger of satellite Spitzenkörper with the main Spitzenkörper. These findings are consistent with a causal relationship between fluctuations in the overall rate of secretory vesicle delivery/discharge at the hyphal apex and the fluctuations in hyphal elongation rate.

Growth kinetics of tin oxide nanocrystals in colloidal suspensions under hydrothermal conditions

International Nuclear Information System (INIS)

Lee, Eduardo J.H.; Ribeiro, Caue; Longo, Elson; Leite, Edson R.

2006-01-01

Colloidal suspensions of tin oxide nanocrystals were synthesized at room temperature by the hydrolysis reaction of tin chloride (II), in an ethanolic solution. The coarsening kinetics of such nanocrystals was studied by submitting the as-prepared suspensions to hydrothermal treatments at temperatures of 100, 150 and 200 deg. C for periods between 60 and 12,000 min. Transmission electron microscopy (TEM) was used to characterize the samples (i.e. distribution of nanocrystal size, average particle radius and morphology). The results show that the usual Ostwald ripening coarsening mechanism does not fit well the experimental data, which is an indicative that this process is not significant for SnO 2 nanocrystals, in the studied experimental conditions. The morphology evolution of the nanocrystals upon hydrothermal treatment indicates that growth by oriented attachment (OA) should be significant. A kinetic model that describes OA growth is successfully applied to fit the data

The kinetics of dolomite reaction rim growth under isostatic and non-isostatic pressure conditions

Science.gov (United States)

Helpa, V.; Rybacki, E.; Morales, L. G.; Abart, R.; Dresen, G. H.

2013-12-01

During burial and exhumation, rocks are simultaneously exposed to metamorphic reactions and tectonic stresses. Therefore, the reaction rate of newly formed minerals may depend on chemical and mechanical driving forces. Here, we investigate the reaction kinetics of dolomite (CaMg[CO3]2) rim growth by solid-state reactions experiments on oriented calcite (CaCO3) and magnesite (MgCO3) single crystals under isostatic and non-isostatic pressure conditions. Cylindrical samples of 3-5 mm length and 7 mm diameter were drilled and polished perpendicular to the rhombohedral cleavage planes of natural clear crystals. The tests were performed using a Paterson-type deformation apparatus at P = 400 MPa confining pressure, temperatures, T, between 750 and 850°C, and reaction durations, t, of 2 - 146 h to calculate the kinetic parameters of dolomite rim growth under isostatic stress conditions. For non-isostatic reaction experiments we applied in addition differential stresses, σ, up to 40 MPa perpendicular to the contact interface at T = 750°C for 4 - 171 h duration, initiating minor inelastic deformation of calcite. The thickness of the resulting dolomite reaction rims increases linearly with the square root of time, indicating a diffusion-controlled reaction. The rims consist of two different textural domains. Granular dolomite grains (≈ 2 -5 μm grain size) form next to calcite and elongated palisade-shaped grains (1-6 μm diameter) grow perpendicular to the magnesite interface. Texture measurements with the electron backscatter diffraction technique indicate that the orientations of dolomite grains are mainly influenced by the orientation of the calcite educt crystal, in particular in the granular rim. To some extent, the texture of dolomite palisades is also influenced by the orientation of magnesite. The thickness of the two individual layers increases with temperature. At 400 MPa isostatic pressure, T = 750°C and t = 29 hours, a 5 μm thick granular dolomite layer

Analysis of grain growth process in melt spun Fe-B alloys under the initial saturated grain boundary segregation condition

International Nuclear Information System (INIS)

Chen, Z.; Liu, F.; Yang, X.Q.; Fan, Y.; Shen, C.J.

2012-01-01

Highlights: → We compared pure kinetic, pure thermodynamic and extended thermo-kinetic models. → An initial saturated GB segregation condition of nanoscale Fe-B alloys was determined. → The controlled-mechanism was proposed using two characteristic times (t 1 and t 2 ). - Abstract: A grain growth process in the melt spun low-solid-solubility Fe-B alloys was analyzed under the initial saturated grain boundary (GB) segregation condition. Applying melt spinning technique, single-phase supersaturated nanograins were prepared. Grain growth behavior of the single-phase supersaturated nanograins was investigated by performing isothermal annealing at 700 deg. C. Combined with the effect of GB segregation on the initial GB excess amount, the thermo-kinetic model [Chen et al., Acta Mater. 57 (2009) 1466] was extended to describe the initial GB segregation condition of nanoscale Fe-B alloys. In comparison of pure kinetic model, pure thermodynamic model and the extended thermo-kinetic model, an initial saturated GB segregation condition was determined. The controlled-mechanism of grain growth under initial saturated GB segregation condition was proposed using two characteristic annealing times (t 1 and t 2 ), which included a mainly kinetic-controlled process (t ≤ t 1 ), a transition from kinetic-mechanism to thermodynamic-mechanism (t 1 2 ) and pure thermodynamic-controlled process (t ≥ t 2 ).

The effect of bedload transport rates on bedform and planform morphological development in a laboratory meandering stream under varying flow conditions

Science.gov (United States)

Sullivan, C.; Good, R. G. R.; Binns, A. D.

2017-12-01

Sediment transport processes in streams provides valuable insight into the temporal evolution of planform and bedform geometry. The majority of previous experimental research in the literature has focused on bedload transport and corresponding bedform development in rectangular, confined channels, which does not consider planform adjustment processes in streams. In contrast, research conducted with laboratory streams having movable banks can investigate planform development in addition to bedform development, which is more representative of natural streams. The goal of this research is to explore the relationship between bedload transport rates and the morphological adjustments in meandering streams. To accomplish this, a series of experimental runs were conducted in a 5.6 m by 1.9 m river basin flume at the University of Guelph to analyze the bedload impacts on bed formations and planform adjustments in response to varying flow conditions. In total, three experimental runs were conducted: two runs using steady state conditions and one run using unsteady flow conditions in the form of a symmetrical hydrograph implementing quasi steady state flow. The runs were performed in a series of time-steps in order to monitor the evolution of the stream morphology and the bedload transport rates. Structure from motion (SfM) was utilized to capture the channel morphology after each time-step, and Agisoft PhotoScan software was used to produce digital elevation models to analyze the morphological evolution of the channel with time. Bedload transport rates were quantified using a sediment catch at the end of the flume. Although total flow volumes were similar for each run, the morphological evolution and bedload transport rates in each run varied. The observed bedload transport rates from the flume are compared with existing bedload transport formulas to assess their accuracy with respect to sediment transport in unconfined meandering channels. The measured sediment transport

Growth Responses of Wheat (Triticum aestivumL. var. HD 2329 Exposed to Ambient Air Pollution under Varying Fertility Regimes

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Anoop Singh

2003-01-01

Full Text Available The problem of urban air pollution has attracted special attention in India due to a tremendous increase in the urban population; motor vehicles vis a vis the extent of energy utilization. Field studies were conducted on wheat crops (Triticum aestivum L. var. HD 2329 by keeping the pot-grown plants in similar edaphic conditions at nine different sites in Allahabad City to quantify the effects of ambient air pollution levels on selected growth and yield parameters. Air quality monitoring was done at all the sites for gaseous pollutants viz. SO2, NO2, and O3. Various growth parameters (plant height, biomass, leaf area, NPP, etc. showed adverse effects at sites receiving higher pollution load. Reduction in test weight and harvest index was found to be directly correlated with the levels of pollutant concentrations. The study clearly showed the negative impact of air pollution on periurban agriculture.

Determination of the rate of crystal growth from the gas phase under conditions of turbulent free convection

Science.gov (United States)

Alad'Ev, S. I.

1987-04-01

Crystal growth in vertical and horizontal cylindrical vials, with the substrate and the source serving as the vial ends, is investigated analytically, assuming that the medium consists of a binary mixture of an active and an inert gas. The active gas is made up of the gaseous products of reactions taking place at the substrate and at the source. It is shown that turbulent free convection leads to an increase in crystal growth rate. All other conditions being equal, crystal growth in vertical vials is greater than that in horizontal ones; in both cases crystal growth rate increases with the vial radius, temperature gradient in the gas phase, and gas phase density. The results are compared with experimental data on the growth of Ge crystals in the Ge-GeI4 system.

Synthesis of different-sized silver nanoparticles by simply varying reaction conditions with leaf extracts of Bauhinia variegata L.

Science.gov (United States)

Kumar, V; Yadav, S K

2012-03-01

Green synthesis of nanoparticles is one of the crucial requirements in today's climate change scenario all over the world. In view of this, leaf extract (LE) of Bauhinia variegata L. possessing strong antidiabetic and antibacterial properties has been used to synthesise silver nanoparticles (SNP) in a controlled manner. Various-sized SNP (20-120 nm) were synthesised by varying incubation temperature, silver nitrate and LE concentrations. The rate of SNP synthesis and their size increased with increase in AgNO(3) concentration up to 4 mM. With increase in LE concentration, size and aggregation of SNP was increased. The size and aggregation of SNP were also increased at temperatures above and below 40°C. This has suggested that size and dispersion of SNP can be controlled by varying reaction components and conditions. Polarity-based fractionation of B. variegata LE has suggested that only water-soluble fraction is responsible for SNP synthesis. Fourier transform infrared spectroscopy analysis revealed the attachment of polyphenolic and carbohydrate moieties to SNP. The synthesised SNPs were found stable in double distilled water, BSA and phosphate buffer (pH 7.4). On the contrary, incubation of SNP with NaCl induced aggregation. This suggests the safe use of SNP for various in vivo applications.

The effects of varying sampling intervals on the growth and survival ...

African Journals Online (AJOL)

Four different sampling intervals were investigated during a six-week outdoor nursery management of Heterobranchus longifilis (Valenciennes, 1840) fry in outdoor concrete tanks in order to determine the most suitable sampling regime for maximum productivity in terms of optimum growth and survival of hatchlings and ...

Spatial and temporal variability in growth of southern flounder (Paralichthys lethostigma)

Science.gov (United States)

Midway, Stephen R.; Wagner, Tyler; Arnott, Stephen A.; Biondo, Patrick; Martinez-Andrade, Fernando; Wadsworth, Thomas F.

2015-01-01

Delineation of stock structure is important for understanding the ecology and management of many fish populations, particularly those with wide-ranging distributions and high levels of harvest. Southern flounder (Paralichthys lethostigma) is a popular commercial and recreational species along the southeast Atlantic coast and Gulf of Mexico, USA. Recent studies have provided genetic and otolith morphology evidence that the Gulf of Mexico and Atlantic Ocean stocks differ. Using age and growth data from four states (Texas, Alabama, South Carolina, and North Carolina) we expanded upon the traditional von Bertalanffy model in order to compare growth rates of putative geographic stocks of southern flounder. We improved the model fitting process by adding a hierarchical Bayesian framework to allow each parameter to vary spatially or temporally as a random effect, as well as log transforming the three model parameters (L∞, K, andt0). Multiple comparisons of parameters showed that growth rates varied (even within states) for females, but less for males. Growth rates were also consistent through time, when long-term data were available. Since within-basin populations are thought to be genetically well-mixed, our results suggest that consistent small-scale environmental conditions (i.e., within estuaries) likely drive growth rates and should be considered when developing broader scale management plans.

Ground-based forest harvesting effects on soil physical properties and Douglas-fir growth.

Science.gov (United States)

Adrian Ares; Thomas A. Terry; Richard E. Miller; Harry W. Anderson; Barry L. Flaming

2005-01-01

Soil properties and forest productivity can be affected by heavy equipment used for harvest and site preparation but these impacts vary greatly with site conditions and operational practices. We assessed the effects of ground-based logging on soil physical properties and subsequent Douglas-fir [Pseudotsuga menziesii (Mirb) Franco] growth on a highly...

The influence of MOVPE growth conditions on the shell of core-shell GaN microrod structures

Science.gov (United States)

Schimpke, Tilman; Avramescu, Adrian; Koller, Andreas; Fernando-Saavedra, Amalia; Hartmann, Jana; Ledig, Johannes; Waag, Andreas; Strassburg, Martin; Lugauer, Hans-Jürgen

2017-05-01

A core-shell geometry is employed for most next-generation, three-dimensional opto-electric devices based on III-V semiconductors and grown by metal organic vapor phase epitaxy (MOVPE). Controlling the shape of the shell layers is fundamental for device optimization, however no detailed analysis of the influence of growth conditions has been published to date. We study homogeneous arrays of gallium nitride core-shell microrods with height and diameter in the micrometer range and grown in a two-step selective area MOVPE process. Changes in shell shape and homogeneity effected by deliberately altered shell growth conditions were accurately assessed by digital analysis of high-resolution scanning electron microscope images. Most notably, two temperature regimes could be established, which show a significantly different behavior with regard to material distribution. Above 900 °C of wafer carrier temperature, the shell thickness along the growth axis of the rods was very homogeneous, however variations between vicinal rods increase. In contrast, below 830 °C the shell thickness is higher close to the microrod tip than at the base of the rods, while the lateral homogeneity between neighboring microrods is very uniform. This temperature effect could be either amplified or attenuated by changing the remaining growth parameters such as reactor pressure, structure distance, gallium precursor, carrier gas composition and dopant materials. Possible reasons for these findings are discussed with respect to GaN decomposition as well as the surface and gas phase diffusion of growth species, leading to an improved control of the functional layers in next-generation 3D V-III devices.

Assessing the effects of adaptation measures on optimal water resources allocation under varied water availability conditions

Science.gov (United States)

Liu, Dedi; Guo, Shenglian; Shao, Quanxi; Liu, Pan; Xiong, Lihua; Wang, Le; Hong, Xingjun; Xu, Yao; Wang, Zhaoli

2018-01-01

Human activities and climate change have altered the spatial and temporal distribution of water availability which is a principal prerequisite for allocation of different water resources. In order to quantify the impacts of climate change and human activities on water availability and optimal allocation of water resources, hydrological models and optimal water resource allocation models should be integrated. Given that increasing human water demand and varying water availability conditions necessitate adaptation measures, we propose a framework to assess the effects of these measures on optimal allocation of water resources. The proposed model and framework were applied to a case study of the middle and lower reaches of the Hanjiang River Basin in China. Two representative concentration pathway (RCP) scenarios (RCP2.6 and RCP4.5) were employed to project future climate, and the Variable Infiltration Capacity (VIC) hydrological model was used to simulate the variability of flows under historical (1956-2011) and future (2012-2099) conditions. The water availability determined by simulating flow with the VIC hydrological model was used to establish the optimal water resources allocation model. The allocation results were derived under an extremely dry year (with an annual average water flow frequency of 95%), a very dry year (with an annual average water flow frequency of 90%), a dry year (with an annual average water flow frequency of 75%), and a normal year (with an annual average water flow frequency of 50%) during historical and future periods. The results show that the total available water resources in the study area and the inflow of the Danjiangkou Reservoir will increase in the future. However, the uneven distribution of water availability will cause water shortage problems, especially in the boundary areas. The effects of adaptation measures, including water saving, and dynamic control of flood limiting water levels (FLWLs) for reservoir operation, were

Seasonal variations in ectotherm growth rates: Quantifying growth as an intermittent non steady state compensatory process

Science.gov (United States)

Guarini, J.-M.; Chauvaud, Laurent; Cloern, J.E.; Clavier, J.; Coston-Guarini, J.; Patry, Y.

2011-01-01

Generally, growth rates of living organisms are considered to be at steady state, varying only under environmental forcing factors. For example, these rates may be described as a function of light for plants or organic food resources for animals and these could be regulated (or not) by temperature or other conditions. But, what are the consequences for an individual's growth (and also for the population growth) if growth rate variations are themselves dynamic and not steady state? For organisms presenting phases of dormancy or long periods of stress, this is a crucial question. A dynamic perspective for quantifying short-term growth was explored using the daily growth record of the scallop Pecten maximus (L.). This species is a good biological model for ectotherm growth because the shell records growth striae daily. Independently, a generic mathematical function representing the dynamics of mean daily growth rate (MDGR) was implemented to simulate a diverse set of growth patterns. Once the function was calibrated with the striae patterns, the growth rate dynamics appeared as a forced damped oscillation during the growth period having a basic periodicity during two transitory phases (mean duration 43. days) and appearing at both growth start and growth end. This phase is most likely due to the internal dynamics of energy transfer within the organism rather than to external forcing factors. After growth restart, the transitory regime represents successive phases of over-growth and regulation. This pattern corresponds to a typical representation of compensatory growth, which from an evolutionary perspective can be interpreted as an adaptive strategy to coping with a fluctuating environment. ?? 2011 Elsevier B.V.

Stand conditions immediately following a restoration harvest in an old-growth pine-hardwood remnant

Science.gov (United States)

D. C. Bragg

2010-01-01

Portions of the Levi Wilcoxon Demonstration Forest (LWDF), a privately owned parcel of old-growth pine and hardwoods in Ashley County, Arkansas, were recently treated to restore conditions similar to some historic accounts of the virgin forest. Following a hardwood-only cut, a post-harvest inventory showed that the number of tree species in the sample area declined...

THE EMPLOYMENT – PRODUCTIVITY – SALARY RELATION, A CONDITION FOR ACHIEVING LONG - TERM ECONOMIC GROWTH

Directory of Open Access Journals (Sweden)

Mihai CHIRILA

2005-01-01

Full Text Available The employment-productivity-salary correlation is essential towards setting up conditions for economic growth andlasting social stability. An influence exists from technological changes, current stage of economic development,peculiarities of labour offer, employers – trade-unions interaction, etc. The analysis covers long-term and short-termcycles. In keeping with specificity of development stages, national economy witnesses an interval of productivitygrowth facilitating maximized employment and a rise in salary too. A lower growth rate indicates difficulties inassimilating new technologies; a higher growth rate generates instability in employing labour. Thus, the exercise ofstrong pressure is shown to exist on economic and technological structures. Likewise, this is what happens whenproductivity goes ahead of the separate analyses of the correlations between employment and productivity, on theone hand, and productivity and salary, on the other.

Growth kinetics and long-term stability of CdS nanoparticles in aqueous solution under ambient conditions

International Nuclear Information System (INIS)

Mullaugh, Katherine M.; Luther, George W.

2011-01-01

The ubiquity of naturally occurring nanoparticles in the aquatic environment is now widely accepted, but a better understanding of the conditions that promote their formation and persistence is needed. Using cadmium sulfide (CdS) as a model metal sulfide species, thiolate-capped CdS nanoparticles were prepared in the laboratory to evaluate how aquatic conditions influence metal sulfide nanoparticle growth and stability. This work examines CdS nanoparticle growth directly in aqueous solution at room temperature by utilizing the size-dependent spectroscopic properties of semiconductors detectable by UV/vis. CdS nanoparticle growth was governed by oriented attachment, a non-classical mechanism of crystallization in which small precursor nanoparticles coalesce to form larger nanoparticle products. Nanoparticle growth was slowed with increasing capping agent and decreasing ionic strength. In addition to examining the short-term (hours) growth of the nanoparticles, a long-term study was conducted in which cysteine-capped CdS nanoparticles were monitored over 3 weeks in solutions of various ionic strengths. The long-term study revealed an apparent shift from small nanoparticles to nanoparticles twice their original size, suggesting nanoparticle growth may continue through oriented attachment over longer time scales. High-ionic strength solutions resulted in salt-induced aggregation and eventual settling of nanoparticles within days, whereas low-ionic strength solutions were stable against settling over the course of the experiment. Sulfide recovery from cysteine-capped CdS nanoparticles as acid volatile sulfide was nearly quantitative after 2 weeks in fully oxygenated water, demonstrating significantly slowed oxidation of sulfide when complexed to Cd(II) within CdS nanoparticles. The nanoparticles were also shown to be resistant to oxidation by Fe(III) (hydr)oxide. This study illustrates that aggregation, rather than chemical oxidation, is likely more important to the

Standard test method for creep-fatigue crack growth testing

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 This test method covers the determination of creep-fatigue crack growth properties of nominally homogeneous materials by use of pre-cracked compact type, C(T), test specimens subjected to uniaxial cyclic forces. It concerns fatigue cycling with sufficiently long loading/unloading rates or hold-times, or both, to cause creep deformation at the crack tip and the creep deformation be responsible for enhanced crack growth per loading cycle. It is intended as a guide for creep-fatigue testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. Therefore, this method requires testing of at least two specimens that yield overlapping crack growth rate data. The cyclic conditions responsible for creep-fatigue deformation and enhanced crack growth vary with material and with temperature for a given material. The effects of environment such as time-dependent oxidation in enhancing the crack growth ra...

Effect of growth conditions on the Al composition and optical properties of Al x Ga 1−x N layers grown by atmospheric-pressure metal organic vapor phase epitaxy

KAUST Repository

Soltani, S.

2017-02-17

The effect of growth conditions on the Al composition and optical properties of AlxGa1-xN layers grown by atmospheric-pressure metal organic vapor phase epitaxy is investigated. The Al content of the samples is varied between 3.0% and 9.3% by changing the gas flow rate of either trimethylaluminum (TMA) or trimethylgallium (TMG) while other growth parameters are kept constant. The optical properties of the AlxGa1-xN layers are studied by photoreflectance and time-resolved photoluminescence (TR-PL) spectroscopies. A degeneration in the material quality of the samples is revealed when the Al content is increased by increasing the TMA flow rate. When the TMG flow rate is decreased with a fixed TMA flow rate, the Al content of the AlxGa1-xN layers is increased and, furthermore, an improvement in the optical properties corresponding with an increase in the PL decay time is observed. (C) 2017 Elsevier B.V. All rights reserved.

Effect of growth conditions on the Al composition and optical properties of Al x Ga 1−x N layers grown by atmospheric-pressure metal organic vapor phase epitaxy

KAUST Repository

Soltani, S.; Bouzidi, M.; Chine, Z.; Toure, A.; Halidou, I.; El Jani, B.; Shakfa, M. K.

2017-01-01

The effect of growth conditions on the Al composition and optical properties of AlxGa1-xN layers grown by atmospheric-pressure metal organic vapor phase epitaxy is investigated. The Al content of the samples is varied between 3.0% and 9.3% by changing the gas flow rate of either trimethylaluminum (TMA) or trimethylgallium (TMG) while other growth parameters are kept constant. The optical properties of the AlxGa1-xN layers are studied by photoreflectance and time-resolved photoluminescence (TR-PL) spectroscopies. A degeneration in the material quality of the samples is revealed when the Al content is increased by increasing the TMA flow rate. When the TMG flow rate is decreased with a fixed TMA flow rate, the Al content of the AlxGa1-xN layers is increased and, furthermore, an improvement in the optical properties corresponding with an increase in the PL decay time is observed. (C) 2017 Elsevier B.V. All rights reserved.

Optimizing pentacene thin-film transistor performance: Temperature and surface condition induced layer growth modification.

Science.gov (United States)

Lassnig, R; Hollerer, M; Striedinger, B; Fian, A; Stadlober, B; Winkler, A

2015-11-01

In this work we present in situ electrical and surface analytical, as well as ex situ atomic force microscopy (AFM) studies on temperature and surface condition induced pentacene layer growth modifications, leading to the selection of optimized deposition conditions and entailing performance improvements. We prepared p ++ -silicon/silicon dioxide bottom-gate, gold bottom-contact transistor samples and evaluated the pentacene layer growth for three different surface conditions (sputtered, sputtered + carbon and unsputtered + carbon) at sample temperatures during deposition of 200 K, 300 K and 350 K. The AFM investigations focused on the gold contacts, the silicon dioxide channel region and the highly critical transition area. Evaluations of coverage dependent saturation mobilities, threshold voltages and corresponding AFM analysis were able to confirm that the first 3-4 full monolayers contribute to the majority of charge transport within the channel region. At high temperatures and on sputtered surfaces uniform layer formation in the contact-channel transition area is limited by dewetting, leading to the formation of trenches and the partial development of double layer islands within the channel region instead of full wetting layers. By combining the advantages of an initial high temperature deposition (well-ordered islands in the channel) and a subsequent low temperature deposition (continuous film formation for low contact resistance) we were able to prepare very thin (8 ML) pentacene transistors of comparably high mobility.

Ellipsometry with randomly varying polarization states

NARCIS (Netherlands)

Liu, F.; Lee, C. J.; Chen, J. Q.; E. Louis,; van der Slot, P. J. M.; Boller, K. J.; F. Bijkerk,

2012-01-01

We show that, under the right conditions, one can make highly accurate polarization-based measurements without knowing the absolute polarization state of the probing light field. It is shown that light, passed through a randomly varying birefringent material has a well-defined orbit on the Poincar

Metabolic enzyme cost explains variable trade-offs between microbial growth rate and yield.

Directory of Open Access Journals (Sweden)

Meike T Wortel

2018-02-01

Full Text Available Microbes may maximize the number of daughter cells per time or per amount of nutrients consumed. These two strategies correspond, respectively, to the use of enzyme-efficient or substrate-efficient metabolic pathways. In reality, fast growth is often associated with wasteful, yield-inefficient metabolism, and a general thermodynamic trade-off between growth rate and biomass yield has been proposed to explain this. We studied growth rate/yield trade-offs by using a novel modeling framework, Enzyme-Flux Cost Minimization (EFCM and by assuming that the growth rate depends directly on the enzyme investment per rate of biomass production. In a comprehensive mathematical model of core metabolism in E. coli, we screened all elementary flux modes leading to cell synthesis, characterized them by the growth rates and yields they provide, and studied the shape of the resulting rate/yield Pareto front. By varying the model parameters, we found that the rate/yield trade-off is not universal, but depends on metabolic kinetics and environmental conditions. A prominent trade-off emerges under oxygen-limited growth, where yield-inefficient pathways support a 2-to-3 times higher growth rate than yield-efficient pathways. EFCM can be widely used to predict optimal metabolic states and growth rates under varying nutrient levels, perturbations of enzyme parameters, and single or multiple gene knockouts.

In vitro maintenance, under slow-growth conditions, of oil palm germplasm obtained by embryo rescue

Directory of Open Access Journals (Sweden)

Julcéia Camillo

2015-05-01

Full Text Available The objective of this work was to evaluate the in vitro maintenance of oil palm (Elaeis guineensis and E. oleifera accessions under slow-growth conditions. Plants produced by embryo rescue were subject to 1/2MS culture medium supplemented with the carbohydrates sucrose, mannitol, and sorbitol at 1, 2, and 3% under 20 and 25±2ºC. After 12 months, the temperature of 20°C reduced plant growth. Sucrose is the most appropriate carbohydrate for maintaining the quality of the plants, whereas mannitol and sorbitol result in a reduced plant survival.

Pre-Swirl Stator and Propeller Design for Varying Operating Conditions

DEFF Research Database (Denmark)

Saettone, Simone; Regener, Pelle Bo; Andersen, Poul

2016-01-01

blades ahead of the propeller.This paper describes the hydrodynamic design of apre-swirl stator with radially variable pitch, paired with aconventional propeller. The aim is to achieve the highest possible effciency in various operating conditions, and to avoid effciency penalties in off-design operation.......To investigate the propeller and stator designs and configurations in different operating conditions, the computationally inexpensive vortex-lattice method is used a sa first step to optimize the geometry in an initial parameter study. Then the flow over hull, stator and propelleris simulated in a CFD...

Effect of Varying Acid Hydrolysis Condition in Gracilaria Sp. Fermentation Using Sasad

Science.gov (United States)

Mansuit, H.; Samsuri, M. D. C.; Sipaut, C. S.; Yee, C. F.; Yasir, S. M.; Mansa, R.

2015-04-01

Macroalgae or seaweed is being considered as promising feedstock for bioalcohol production due to high polysaccharides content. Polysaccharides can be converted into fermentable sugar through acid hydrolysis pre-treatment. In this study, the potential of using carbohydrate-rich macroalgae, Gracilaria sp. as feedstock for bioalcohol production via various acid hydrolysis conditions prior to the fermentation process was investigated and evaluated. The seaweed used in this research was from the red algae group, using species of Gracilaria sp. which was collected from Sg. Petani Kedah, Malaysia. Pre-treatment of substrate was done using H2SO4 and HCl with molarity ranging from 0.2M to 0.8M. The pretreatment time were varied in the range of 15 to 30 minutes. Fermentation was conducted using Sasad, a local Sabahan fermentation agent as a starter culture. Alcohol extraction was done using a distillation unit. Reducing sugar analysis was done by Benedict test method. Alcohol content analysis was done using specific gravity test. After hydrolysis, it was found out that acid hydrolysis at 0.2M H2SO4 and pre-treated for 20 minutes at 121°C has shown the highest reducing sugar content which has yield (10.06 mg/g) of reducing sugar. It was followed by other samples hydrolysis using 0.4M HCl with 30 minutes pre-treatment and 0.2M H2SO4, 15 minutes pre-treatment with yield of 8.06 mg/g and 5.75 mg/g reducing sugar content respectively. In conclusion, acid hydrolysis of Gracilaria sp. can produce higher reducing sugar yield and thus it can further enhance the bioalcohol production yield. Hence, acid hydrolysis of Gracilaria sp. should be studied more as it is an important step in the bioalcohol production and upscaling process.

Effects of Different Ectomycorrhizal Fungal Inoculates on the Growth of Pinus tabulaeformis Seedlings under Greenhouse Conditions

Directory of Open Access Journals (Sweden)

Nan Lu

2016-12-01

Full Text Available The tree species Pinus tabulaeformis Carr. (P. tabulaeformis is commonly planted in China due to its economic and ecological value. In order to identify one or more ectomycorrhizal (ECM fungal species for future P. tabulaeformis afforestation, we investigated the effects of five ECM fungal species: Laccaria laccata, Boletus edulis, Gomphidius viscidus, Suillus grevillei, and Suillus luteus on the growth of P. tabulaeformis seedlings under greenhouse conditions. The growth parameters of P. tabulaeformis seedlings were evaluated 90 days following fungal colonisation. The majority of seedlings were significantly affected by ECM inoculation. Mycorrhizal inoculated seedlings were taller, had more lateral roots, and a greater biomass compared with the non-mycorrhizal (CK seedlings. With the exception of G. viscidus, inoculated seedlings exhibited higher phosphorus, potassium, and nitrogen content compared with the CK seedlings. In addition, ECM colonisation increased the enzymatic activity of catalase, acidic phosphatase, protease, and the urease content in the rhizosphere soil. Our study showed that Laccaria laccata, Suillus grevillei, and Suillus luteus may be useful for improving the growth and cultivation of P. tabulaeformis seedlings. Furthermore, we observed that S. luteus inoculation increased the gas exchange parameters of P. tabulaeformis seedlings under field conditions.

Development of disease-specific growth charts in Turner syndrome and Noonan syndrome

Directory of Open Access Journals (Sweden)

Tsuyoshi Isojima

2017-12-01

Full Text Available Many congenital diseases are associated with growth failure, and patients with these diseases have specific growth patterns. As the growth patterns of affected individuals differ from those of normal populations, it is challenging to detect additional conditions that can influence growth using standard growth charts. Disease-specific growth charts are thus very useful tools and can be helpful for understanding the growth pattern and pathogenesis of congenital diseases. In addition, disease-specific growth charts allow doctors to detect deviations from the usual growth patterns for early diagnosis of an additional condition and can be used to evaluate the effects of growth-promoting treatment for patients. When developing these charts, factors that can affect the reliability of the charts should be considered. These factors include the definition of the disease with growth failure, selection bias in the measurements used to develop the charts, secular trends of the subjects, the numbers of subjects of varying ages and ethnicities, and the statistical method used to develop the charts. In this review, we summarize the development of disease-specific growth charts for Japanese individuals with Turner syndrome and Noonan syndrome and evaluate the efforts to collect unbiased measurements of subjects with these diseases. These charts were the only available disease-specific growth charts of Turner syndrome and Noonan syndrome for Asian populations and were developed using a Japanese population. Therefore, when these charts are adopted for Asian populations other than Japanese, different growth patterns should be considered.

Development of disease-specific growth charts in Turner syndrome and Noonan syndrome.

Science.gov (United States)

Isojima, Tsuyoshi; Yokoya, Susumu

2017-12-01

Many congenital diseases are associated with growth failure, and patients with these diseases have specific growth patterns. As the growth patterns of affected individuals differ from those of normal populations, it is challenging to detect additional conditions that can influence growth using standard growth charts. Disease-specific growth charts are thus very useful tools and can be helpful for understanding the growth pattern and pathogenesis of congenital diseases. In addition, disease-specific growth charts allow doctors to detect deviations from the usual growth patterns for early diagnosis of an additional condition and can be used to evaluate the effects of growth-promoting treatment for patients. When developing these charts, factors that can affect the reliability of the charts should be considered. These factors include the definition of the disease with growth failure, selection bias in the measurements used to develop the charts, secular trends of the subjects, the numbers of subjects of varying ages and ethnicities, and the statistical method used to develop the charts. In this review, we summarize the development of disease-specific growth charts for Japanese individuals with Turner syndrome and Noonan syndrome and evaluate the efforts to collect unbiased measurements of subjects with these diseases. These charts were the only available disease-specific growth charts of Turner syndrome and Noonan syndrome for Asian populations and were developed using a Japanese population. Therefore, when these charts are adopted for Asian populations other than Japanese, different growth patterns should be considered.

Automatic Traffic Data Collection under Varying Lighting and Temperature Conditions in Multimodal Environments: Thermal versus Visible Spectrum Video-Based Systems

Directory of Open Access Journals (Sweden)

Ting Fu

2017-01-01

Full Text Available Vision-based monitoring systems using visible spectrum (regular video cameras can complement or substitute conventional sensors and provide rich positional and classification data. Although new camera technologies, including thermal video sensors, may improve the performance of digital video-based sensors, their performance under various conditions has rarely been evaluated at multimodal facilities. The purpose of this research is to integrate existing computer vision methods for automated data collection and evaluate the detection, classification, and speed measurement performance of thermal video sensors under varying lighting and temperature conditions. Thermal and regular video data was collected simultaneously under different conditions across multiple sites. Although the regular video sensor narrowly outperformed the thermal sensor during daytime, the performance of the thermal sensor is significantly better for low visibility and shadow conditions, particularly for pedestrians and cyclists. Retraining the algorithm on thermal data yielded an improvement in the global accuracy of 48%. Thermal speed measurements were consistently more accurate than for the regular video at daytime and nighttime. Thermal video is insensitive to lighting interference and pavement temperature, solves issues associated with visible light cameras for traffic data collection, and offers other benefits such as privacy, insensitivity to glare, storage space, and lower processing requirements.

On the influence of abiotic stress conditions on growth of barley and bean and their predisposition for pathogens

Energy Technology Data Exchange (ETDEWEB)

Oerke, E.C.; Schoenbeck, F.

1986-01-01

Shorttime changes of environmental conditions stressed barley and bean and affected plant growth and their predisposition for various pathogens. Moderate stress intensities as low or high temperatures, water or light deficits, increased the susceptibility to Erysiphe graminis var. hordei or Uromyces phaseoli and reduced disease level of spot blotch caused by Cochliobolus sativus, respectively. There was only little effect on plant growth in that case. Intensive stress as a result of combinations of unfavorable environmental conditions or longtime continuance of moderate stress reduced the plant growth and turned the predisposing effect to the opposite: after the treatment, plants were more resistent to diseases caused by biotrophic fungi, whereas there was increased susceptibility to the perthotrophic fungus. High intensities of fertilization acted as an additional stress and intensified the plant reaction to environmental alterations. The variation of the predisposition is discussed in relation to stress intensity.

Sibling Competition & Growth Tradeoffs. Biological vs. Statistical Significance.

Science.gov (United States)

Kramer, Karen L; Veile, Amanda; Otárola-Castillo, Erik

2016-01-01

Early childhood growth has many downstream effects on future health and reproduction and is an important measure of offspring quality. While a tradeoff between family size and child growth outcomes is theoretically predicted in high-fertility societies, empirical evidence is mixed. This is often attributed to phenotypic variation in parental condition. However, inconsistent study results may also arise because family size confounds the potentially differential effects that older and younger siblings can have on young children's growth. Additionally, inconsistent results might reflect that the biological significance associated with different growth trajectories is poorly understood. This paper addresses these concerns by tracking children's monthly gains in height and weight from weaning to age five in a high fertility Maya community. We predict that: 1) as an aggregate measure family size will not have a major impact on child growth during the post weaning period; 2) competition from young siblings will negatively impact child growth during the post weaning period; 3) however because of their economic value, older siblings will have a negligible effect on young children's growth. Accounting for parental condition, we use linear mixed models to evaluate the effects that family size, younger and older siblings have on children's growth. Congruent with our expectations, it is younger siblings who have the most detrimental effect on children's growth. While we find statistical evidence of a quantity/quality tradeoff effect, the biological significance of these results is negligible in early childhood. Our findings help to resolve why quantity/quality studies have had inconsistent results by showing that sibling competition varies with sibling age composition, not just family size, and that biological significance is distinct from statistical significance.

Sibling Competition & Growth Tradeoffs. Biological vs. Statistical Significance.

Directory of Open Access Journals (Sweden)

Karen L Kramer

Full Text Available Early childhood growth has many downstream effects on future health and reproduction and is an important measure of offspring quality. While a tradeoff between family size and child growth outcomes is theoretically predicted in high-fertility societies, empirical evidence is mixed. This is often attributed to phenotypic variation in parental condition. However, inconsistent study results may also arise because family size confounds the potentially differential effects that older and younger siblings can have on young children's growth. Additionally, inconsistent results might reflect that the biological significance associated with different growth trajectories is poorly understood. This paper addresses these concerns by tracking children's monthly gains in height and weight from weaning to age five in a high fertility Maya community. We predict that: 1 as an aggregate measure family size will not have a major impact on child growth during the post weaning period; 2 competition from young siblings will negatively impact child growth during the post weaning period; 3 however because of their economic value, older siblings will have a negligible effect on young children's growth. Accounting for parental condition, we use linear mixed models to evaluate the effects that family size, younger and older siblings have on children's growth. Congruent with our expectations, it is younger siblings who have the most detrimental effect on children's growth. While we find statistical evidence of a quantity/quality tradeoff effect, the biological significance of these results is negligible in early childhood. Our findings help to resolve why quantity/quality studies have had inconsistent results by showing that sibling competition varies with sibling age composition, not just family size, and that biological significance is distinct from statistical significance.

Stressful dieting: nutritional conditions but not compensatory growth elevate corticosterone levels in zebra finch nestlings and fledglings.

Directory of Open Access Journals (Sweden)

Mariam Honarmand

Full Text Available Unfavourable conditions throughout the period of parental care can severely affect growth, reproductive performance, and survival. Yet, individuals may be affected differently, depending on the developmental period during which constraints are experienced. Here we tested whether the nestling phase compared to the fledgling phase is more susceptible to nutritional stress by considering biometry, physiology, sexually selected male ornaments and survival using zebra finches (Taeniopygia guttata as a model species. As nestlings (day 0-17 or fledglings (day 17-35, subjects were raised either on low or high quality food. A low quality diet resulted in significantly elevated baseline corticosterone titres in both nestlings and fledglings. Subjects showed substantial compensatory growth after they had experienced low quality food as nestlings but catch-up growth did neither lead to elevated baseline corticosterone titres nor did we detect long term effects on biometry, male cheek patch, or survival. The compensation for temporally unfavourable environmental conditions reflects substantial phenotypic plasticity and the results show that costs of catch-up growth were not mediated via corticosterone as a physiological correlate of allostatic load. These findings provide new insights into the mechanisms and plasticity with which animals respond to periods of constraints during development as they may occur in a mistiming of breeding.

Modulating the phenology and yield of camelina sativa L. by varying sowing dates under water deficit stress conditions

Directory of Open Access Journals (Sweden)

Ejaz Ahmad Waraich

2017-05-01

Full Text Available Camelina (Camelina sativa L. an oilseed crop has emerged as a potential source for biofuels and bio-products. Camelina is an economic crop due to its less requirements of agronomic inputs as compared to other oilseed crops. However, it is direly required to evaluate the adaptability of camelina and characterize its production potential. Therefore, a pot experiment was carried out in rain out shelter at the Department of Agronomy, University of Agriculture, Faisalabad, Pakistan to optimize appropriate sowing date with respect to growth and yield potential of different genotypes of camelina under drought stress. Completely randomized design with factorial arrangements was adopted. Three sowing dates with the difference of 10 days (November 13 th, 23rd and December 03rd, two water regimes (100% FC and 60% FC and two camlena genotypes (611 and 618 were used in this experiment. Results indicated that camelina growth and yield related traits were significantly influenced by difference in sowing dates and water regimes. Maximum leaf area index (LAI, crop growth rate (CGR, leaf area duration (LAD, net assimilation rate (NAR and yield related traits were recorded with early sowing (13th November which was followed by sowing on 23rd November and least values of these variables were recorded in late sowing (December 03rd. Plants grown under water deficit conditions (60% FC showed the decreased values of LAI, CGR, LAD, NAR and yield related attributes as compared to normally irrigated plants (100% FC. However, the response of genotypes of camelina 611 and 618 remained statistically similar to each other.

Improving growth performance in calves under hot weather conditions

International Nuclear Information System (INIS)

Emara, S.S.M.

2009-01-01

The main objectives of the present study were to evaluate the effect of some supplement such as dried live yeast DLY (Saccharomyces cerevisiae), DLY + vitamin E and / or dried whey milk (DWM) on blood constituents and thyroid activity in relation to some immune indices and growth performance of calves under hot weather conditions. The ambient temperature and relative humidity averaged 36.9±4 degree C and 43-58 % during day and 29±4 degree C and 60-68 % during night, respectively, which were equivalent to temperature humidity index of 86-89 during day and 78-80 during night . The present study included three experiments as follows. Experiment 1 : Six female bovine Baladi calves of 8-10 months old and 100 kg initial body weight (IBW) were used during two periods. In the first period, the calves were offered the basal diet for one month and considered as a control period. In the second period, the same calves were fed the same basal diet which supplemented with 15 g / calf/ day DLY for one month and considered as treated period. The obtained results indicated that supplementation of DLY reduced significantly the respiration rate (RR) and rectal temperature (RT) as well as serum lipids profile including total cholesterol, low density lipoprotein (LDL- cholesterol) very low density lipoprotein (VLDL-cholesterol) triglycerides and phospholipids.The second and third experiments were carried out for improving growth performance of heat-stressed bovine baladi calves by adding DLY and vitamine E (alpha-tocopherol) to their diet in experiment 2 and dried whey milk (DWM) in experiment 3.

PERT: A Method for Expression Deconvolution of Human Blood Samples from Varied Microenvironmental and Developmental Conditions

Science.gov (United States)

Csaszar, Elizabeth; Yu, Mei; Morris, Quaid; Zandstra, Peter W.

2012-01-01

The cellular composition of heterogeneous samples can be predicted using an expression deconvolution algorithm to decompose their gene expression profiles based on pre-defined, reference gene expression profiles of the constituent populations in these samples. However, the expression profiles of the actual constituent populations are often perturbed from those of the reference profiles due to gene expression changes in cells associated with microenvironmental or developmental effects. Existing deconvolution algorithms do not account for these changes and give incorrect results when benchmarked against those measured by well-established flow cytometry, even after batch correction was applied. We introduce PERT, a new probabilistic expression deconvolution method that detects and accounts for a shared, multiplicative perturbation in the reference profiles when performing expression deconvolution. We applied PERT and three other state-of-the-art expression deconvolution methods to predict cell frequencies within heterogeneous human blood samples that were collected under several conditions (uncultured mono-nucleated and lineage-depleted cells, and culture-derived lineage-depleted cells). Only PERT's predicted proportions of the constituent populations matched those assigned by flow cytometry. Genes associated with cell cycle processes were highly enriched among those with the largest predicted expression changes between the cultured and uncultured conditions. We anticipate that PERT will be widely applicable to expression deconvolution strategies that use profiles from reference populations that vary from the corresponding constituent populations in cellular state but not cellular phenotypic identity. PMID:23284283

Global stabilization of linear continuous time-varying systems with bounded controls

International Nuclear Information System (INIS)

Phat, V.N.

2004-08-01

This paper deals with the problem of global stabilization of a class of linear continuous time-varying systems with bounded controls. Based on the controllability of the nominal system, a sufficient condition for the global stabilizability is proposed without solving any Riccati differential equation. Moreover, we give sufficient conditions for the robust stabilizability of perturbation/uncertain linear time-varying systems with bounded controls. (author)

Uropathogenic Escherichia coli Express Type 1 Fimbriae Only in Surface Adherent Populations Under Physiological Growth Conditions

DEFF Research Database (Denmark)

Stærk, Kristian; Kolmos, Hans Jørn; Khandige, Surabhi

2016-01-01

were correlated with the ability to adhere to and invade cultured human bladder cells. RESULTS:  Although inactive during planktonic growth in urine, T1F expression occurs when UPEC settles on and infects bladder epithelial cells or colonizes catheters. As a result, UPEC in these sessile populations...... with increased expression during surface growth adaptation and infection of uroepithelial cells. This leads to separation of UPEC into low-expression planktonic populations and high-expression sessile populations....... enhances bladder cell adhesion and invasion potential. Only T1F-negative UPEC are subsequently released to the urine, thus limiting T1F expression to surface-associated UPEC alone. CONCLUSION:  Our results demonstrate that T1F expression is strictly regulated under physiological growth conditions...

Vector population growth and condition-dependent movement drive the spread of plant pathogens.

Science.gov (United States)

Shaw, Allison K; Peace, Angela; Power, Alison G; Bosque-Pérez, Nilsa A

2017-08-01

Plant viruses, often spread by arthropod vectors, impact natural and agricultural ecosystems worldwide. Intuitively, the movement behavior and life history of vectors influence pathogen spread, but the relative contribution of each factor has not been examined. Recent research has highlighted the influence of host infection status on vector behavior and life history. Here, we developed a model to explore how vector traits influence the spread of vector-borne plant viruses. We allowed vector life history (growth rate, carrying capacity) and movement behavior (departure and settlement rates) parameters to be conditional on whether the plant host is infected or healthy and whether the vector is viruliferous (carrying the virus) or not. We ran simulations under a wide range of parameter combinations and quantified the fraction of hosts infected over time. We also ran case studies of the model for Barley yellow dwarf virus, a persistently transmitted virus, and for Potato virus Y, a non-persistently transmitted virus. We quantified the relative importance of each parameter on pathogen spread using Latin hypercube sampling with the statistical partial rank correlation coefficient technique. We found two general types of mechanisms in our model that increased the rate of pathogen spread. First, increasing factors such as vector intrinsic growth rate, carrying capacity, and departure rate from hosts (independent of whether these factors were condition-dependent) led to more vectors moving between hosts, which increased pathogen spread. Second, changing condition-dependent factors such as a vector's preference for settling on a host with a different infection status than itself, and vector tendency to leave a host of the same infection status, led to increased contact between hosts and vectors with different infection statuses, which also increased pathogen spread. Overall, our findings suggest that vector population growth rates had the greatest influence on rates of virus

Influence of hydrogen on crack growth rate of alloy 690 CW in PWR conditions

International Nuclear Information System (INIS)

Garcia Redondo, M.S.; Perosanz, F.J.; Lapena, J.; Gomez-Briceno, D.

2015-01-01

The influence of hydrogen concentration is well established for Alloy 600 and other nickel base alloys as Alloy 182/ 82 weld metals and X-750. It is accepted that for these materials maximum crack growth rate peaks close to Ni/NiO phase boundary. The influence of the hydrogen on the CGR of Alloy 690 is not well established. Available results for Alloy 690 are scarce and not conclusive. Results obtained by CIEMAT, in conditions representative of the PWR operating plants, indicated an apparent crack growth rate increase by a 3 factor when the hydrogen concentration increased from 35 to 81 cm -3 of H 2 /kg H 2 O. In order to gain some insight into the influence of the hydrogen, a new test has been performed with 20 cm -3 H 2 /kg H 2 O at 360 Celsius degrees, concentration close to Ni/NiO phase boundary. The material used was extruded control rod drive mechanism (CRDM) tubes with homogeneous microstructure. Rolling and tensile straining was applied to the CRDM material to obtain 20% of cold work in order to simulate the strain condition expected in the Heat Affected Zone (HAZ). (authors)

When bigger is not better: selection against large size, high condition and fast growth in juvenile lemon sharks.

Science.gov (United States)

Dibattista, J D; Feldheim, K A; Gruber, S H; Hendry, A P

2007-01-01

Selection acting on large marine vertebrates may be qualitatively different from that acting on terrestrial or freshwater organisms, but logistical constraints have thus far precluded selection estimates for the former. We overcame these constraints by exhaustively sampling and repeatedly recapturing individuals in six cohorts of juvenile lemon sharks (450 age-0 and 255 age-1 fish) at an enclosed nursery site (Bimini, Bahamas). Data on individual size, condition factor, growth rate and inter-annual survival were used to test the 'bigger is better', 'fatter is better' and 'faster is better' hypotheses of life-history theory. For age-0 sharks, selection on all measured traits was weak, and generally acted against large size and high condition. For age-1 sharks, selection was much stronger, and consistently acted against large size and fast growth. These results suggest that selective pressures at Bimini may be constraining the evolution of large size and fast growth, an observation that fits well with the observed small size and low growth rate of juveniles at this site. Our results support those of some other recent studies in suggesting that bigger/fatter/faster is not always better, and may often be worse.

Resistance of poly(ethylene oxide)-silane monolayers to the growth of polyelectrolyte multilayers.

Science.gov (United States)

Buron, Cédric C; Callegari, Vincent; Nysten, Bernard; Jonas, Alain M

2007-09-11

The ability of poly(ethylene oxide)-silane (PEO-silane) monolayers grafted onto silicon surfaces to resist the growth of polyelectrolyte multilayers under various pH conditions is assessed for different pairs of polyelectrolytes of varying molar mass. For acidic conditions (pH 3), the PEO-silane monolayers exhibit good polyelectrolyte repellency provided the polyelectrolytes bear no moieties that are able to form hydrogen bonds with the ether groups of the PEO chains. At basic pH, PEO-silane monolayers undergo substantial hydrolysis leading to the formation of negatively charged defects in the monolayers, which then play the role of adsorption sites for the polycation. Once the polycation is adsorbed, multilayer growth ensues. Because this is defect-driven growth, the multilayer is not continuous and is made of blobs or an open network of adsorbed strands. For such conditions, the molar mass of the polyelectrolyte plays a key role, with polyelectrolyte chains of larger molar mass adsorbing on a larger number of defects, resulting in stronger anchoring of the polyelectrolyte complex on the surfaces and faster subsequent growth of the multilayer. For polyelectrolytes of sufficiently low molar mass at pH 9, the growth of the multilayer can nevertheless be prevented for as much as five cycles of deposition.

Homogeneity and heterogeneity in amylase production by Bacillus subtilis under different growth conditions.

Science.gov (United States)

Ploss, Tina N; Reilman, Ewoud; Monteferrante, Carmine G; Denham, Emma L; Piersma, Sjouke; Lingner, Anja; Vehmaanperä, Jari; Lorenz, Patrick; van Dijl, Jan Maarten

2016-03-29

Bacillus subtilis is an important cell factory for the biotechnological industry due to its ability to secrete commercially relevant proteins in large amounts directly into the growth medium. However, hyper-secretion of proteins, such as α-amylases, leads to induction of the secretion stress-responsive CssR-CssS regulatory system, resulting in up-regulation of the HtrA and HtrB proteases. These proteases degrade misfolded proteins secreted via the Sec pathway, resulting in a loss of product. The aim of this study was to investigate the secretion stress response in B. subtilis 168 cells overproducing the industrially relevant α-amylase AmyM from Geobacillus stearothermophilus, which was expressed from the strong promoter P(amyQ)-M. Here we show that activity of the htrB promoter as induced by overproduction of AmyM was "noisy", which is indicative for heterogeneous activation of the secretion stress pathway. Plasmids were constructed to allow real-time analysis of P(amyQ)-M promoter activity and AmyM production by, respectively, transcriptional and out-of-frame translationally coupled fusions with gfpmut3. Our results show the emergence of distinct sub-populations of high- and low-level AmyM-producing cells, reflecting heterogeneity in the activity of P(amyQ)-M. This most likely explains the heterogeneous secretion stress response. Importantly, more homogenous cell populations with regard to P(amyQ)-M activity were observed for the B. subtilis mutant strain 168degUhy32, and the wild-type strain 168 under optimized growth conditions. Expression heterogeneity of secretory proteins in B. subtilis can be suppressed by degU mutation and optimized growth conditions. Further, the out-of-frame translational fusion of a gene for a secreted target protein and gfp represents a versatile tool for real-time monitoring of protein production and opens novel avenues for Bacillus production strain improvement.

Ultraviolet-B radiation and nitrogen effects on growth and yield of maize under Mediterranean field conditions

OpenAIRE

Correia, Carlos M.; Coutinho, João F.; Björn, Lars Olof; Torres-Pereira, José M. G.

2000-01-01

The effects of an increase in UV-B radiation on growth and yield of maize (Zea mays L.) were investigated at four levels of applied nitrogen (0, 100, 200 and 300 kg ha−1 of N) under Mediterranean field conditions. The experiment simulated a 20% stratospheric ozone depletion over Portugal. Enhanced UV-B and N deficiency decreased yield and total biomass production by 22–49%. High UV-B dose reduced yield, total biomass and growth of N-fertilized maize plants but did not affect N-stressed plants...

Effects of H2O2 under low- and high-aeration-level conditions on growth and catalase activity in Exiguobacterium oxidotolerans T-2-2T.

Science.gov (United States)

Takebe, Fumihiko; Hara, Isao; Matsuyama, Hidetoshi; Yumoto, Isao

2007-12-01

The effects of H2O2 under low- and high-aeration-level conditions on growth and catalase activity in Exiguobacterium oxidotolerans T-2-2T were investigated. Continuous addition of 5-200 mM H2O2 to the culture medium from the mid-exponential growth phase enhanced the growth of the strain under the low-aeration-level condition, whereas the addition of 5-50 mM H2O2 decreased intracellular specific catalase activity and extracellular total catalases activity. The detection of extracellular catalase by the cells and the decrease in intracellular specific catalase activity and extracellular total catalase activity under the high-aeration-level condition account for the stimulation of growth by the introduced H2O2 and the decrease in catalase activities induced by O(2) from H2O2 in the medium. On the other hand, the addition of H2O2 to the medium prior to the initiation of growth inhibited the growth but increased the specific activity of intracellular catalase in the stationary growth phase. Strain T-2-2T grew when 10 mM H2O2 was added to the medium prior to growth. However, the growth was completely inhibited by the catalase inhibitor 3-amino-1,2,4-triazole (3-AT). The continuous addition of H2O2 at an appropriate concentration from prior to the initiation of growth to the stationary growth phase under the low-aeration-level condition resulted in higher intracellular specific catalase activity and cell growth rate than single H2O2 addition prior to growth.

Effect of Bacillus Species Rhizobacteria on Kabuli Chickpea Plants Growth under Pots and Field Conditions

OpenAIRE

Ait Kaki, Asma; Benhassine, Sara; Milet, Asma; Kara Ali, Monira; Moula, Nassim; Kacem Chaouche, Nordine

2018-01-01

In the present research, some Bacillus strains were produced at the industrial scale in order to be tested on chickpea growth, under pots and field conditions. Bacteria reached high sporulation yields ranging from 0.8×109-2.5×109 and 8×109-10×109 spores mL-1 in flasks and 500 L bioreactor culture conditions, respectively. Under pots experiment, B. amyloliquefaciens (9SRTS) and B. amyloliquefaciens (CWBI) increased significantly the root mass (0.31 and 0.37 vs. 0.066 g, respectively) and reduc...

Volume 9 No. 2 2009 March 2009 700 EFFECT OF VARYING ...

African Journals Online (AJOL)

Ipomea batatas) peels. The varying ... objective is to investigate the effect of sweet potato peels inclusion in fish diet on growth responses of ... were fishmeal, groundnut cake, corn meal, cassava flour, corn oil, α-cellulose, chromic oxide, and ...

Spatial variation in growth, condition and maturation reaction norms of the Baltic herring Clupea harengus membras

NARCIS (Netherlands)

Vainikka, A.; Mollet, F.M.; Casini, M.; Gardmark, A.

2009-01-01

Understanding of spatial patterns in life-history traits can help fisheries management focus on biologically and functionally relevant stock units. In the present study, we examined life-history variation in growth, condition and maturation of the Baltic herring Clupea harengus membras among

Computational Fluid Dynamic Simulation of Single Bubble Growth under High-Pressure Pool Boiling Conditions

Directory of Open Access Journals (Sweden)

Janani Murallidharan

2016-08-01

Full Text Available Component-scale modeling of boiling is predominantly based on the Eulerian–Eulerian two-fluid approach. Within this framework, wall boiling is accounted for via the Rensselaer Polytechnic Institute (RPI model and, within this model, the bubble is characterized using three main parameters: departure diameter (D, nucleation site density (N, and departure frequency (f. Typically, the magnitudes of these three parameters are obtained from empirical correlations. However, in recent years, efforts have been directed toward mechanistic modeling of the boiling process. Of the three parameters mentioned above, the departure diameter (D is least affected by the intrinsic uncertainties of the nucleate boiling process. This feature, along with its prominence within the RPI boiling model, has made it the primary candidate for mechanistic modeling ventures. Mechanistic modeling of D is mostly carried out through solving of force balance equations on the bubble. Forces incorporated in these equations are formulated as functions of the radius of the bubble and have been developed for, and applied to, low-pressure conditions only. Conversely, for high-pressure conditions, no mechanistic information is available regarding the growth rates of bubbles and the forces acting on them. In this study, we use direct numerical simulation coupled with an interface tracking method to simulate bubble growth under high (up to 45 bar pressure, to obtain the kind of mechanistic information required for an RPI-type approach. In this study, we compare the resulting bubble growth rate curves with predictions made with existing experimental data.

Dynamic environments of fungus-farming termite mounds exert growth-modulating effects on fungal crop parasites.

Science.gov (United States)

Katariya, Lakshya; Ramesh, Priya B; Borges, Renee M

2018-03-01

This study investigated for the first time the impact of the internal mound environment of fungus-growing termites on the growth of fungal crop parasites. Mounds of the termite Odontotermes obesus acted as (i) temperature and relative humidity (RH) 'stabilisers' showing dampened daily variation and (ii) 'extreme environments' exhibiting elevated RH and CO 2 levels, compared to the outside. Yet, internal temperatures exhibited seasonal dynamics as did daily and seasonal CO 2 levels. During in situ experiments under termite-excluded conditions within the mound, the growth of the crop parasite Pseudoxylaria was greater inside than outside the mound, i.e., Pseudoxylaria is 'termitariophilic'. Also, ex situ experiments on parasite isolates differing in growth rates and examined under controlled conditions in the absence of termites revealed a variable effect with fungal growth decreasing only under high CO 2 and low temperature conditions, reflecting the in situ parasite growth fluctuations. In essence, the parasite appears to be adapted to survive in the termite mound. Thus the mound microclimate does not inhibit the parasite but the dynamic environmental conditions of the mound affect its growth to varying extents. These results shed light on the impact of animal-engineered structures on parasite ecology, independent of any direct role of animal engineers. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

The effect of isolation on reproduction and growth of Pseudosuccinea columella (Pulmonata: Lymnaeidae: a snail-conditioned water experiment

Directory of Open Access Journals (Sweden)

Gutiérrez Alfredo

2002-01-01

Full Text Available A snail-conditioned water experiment was conducted in Pseudosuccinea columella to test the possible role of a chemical interaction between snails on the diminished growth and fecundity rates found for snails raised in pairs compared to those raised in complete isolation. The results permit to discard the hypothesis of an inhibition of growth and reproduction between snails due to factors released into the water.

Inoculation of Brassica oxyrrhina with plant growth promoting bacteria for the improvement of heavy metal phytoremediation under drought conditions.

Science.gov (United States)

Ma, Ying; Rajkumar, Mani; Zhang, Chang; Freitas, Helena

2016-12-15

The aim of this study was to investigate the effects of drought resistant serpentine rhizobacteria on plant growth and metal uptake by Brassica oxyrrhina under drought stress (DS) condition. Two drought resistant serpentine rhizobacterial strains namely Pseudomonas libanensis TR1 and Pseudomonas reactans Ph3R3 were selected based on their ability to stimulate seedling growth in roll towel assay. Further assessment on plant growth promoting (PGP) parameters revealed their ability to produce indole-3-acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase. Moreover, both strains exhibited high resistance to various heavy metals, antibiotics, salinity and extreme temperature. Inoculation of TR1 and Ph3R3 significantly increased plant growth, leaf relative water and pigment content of B. oxyrrhina, whereas decreased concentrations of proline and malondialdehyde in leaves under metal stress in the absence and presence of DS. Regardless of soil water conditions, TR1 and Ph3R3 greatly improved organ metal concentrations, translocation and bioconcentration factors of Cu and Zn. The successful colonization and metabolic activities of P. libanensis TR1 and P. reactans Ph3R3 represented positive effects on plant development and metal phytoremediation under DS. These results indicate that these strains could be used as bio-inoculants for the improvement of phytoremediation of metal polluted soils under semiarid conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

A numerical study of thermal conditions in the THM growth of HgTe

Science.gov (United States)

Martínez-Tomás, M. C.; Muñoz-Sanjosé, V.; Reig, C.

2002-09-01

A numerical simulation of the travelling heater method (THM) process in the growth of HgTe is carried out. The whole system (furnace, ampoule and charge) is taken into account in the frame of a quasi-steady-state model. The mass conservation condition for the solute in the liquid zone permits the determination of the rate of advance of the crystallisation isotherm as a function of the heater position. We claim to study the evolution of different magnitudes along the growth process, searching for the physical reasons which could be at the origin of defects in the form of thin layers observed in some growing experiences. To solve the governing equations of fluid flow, heat transfer and mass transport we have made use of a commercial code which can run in a PC. The simulation is made by using a three-level strategy, which allows the reduction of the computational effort. In the first level, heat transport is assumed to be by conduction, convection and radiation between the furnace and the ampoule, and by conduction through the ampoule wall, coating, solid and liquid zones. The temperature calculated at this level in the air/ampoule boundary is used as boundary condition for the second and third level. In these two levels the ampoule and its content are studied in detail. Convection in the liquid zone is considered at the second level and thermosolutal convection is finally included at the third level. The analysis of the incoming/outcoming heat flux per second through the ampoule for the whole system shows that the lower part of the ampoule exhibits some ineffectiveness for the heat evacuation at certain positions of the growth run, depending on thermal properties of the whole system and the particular material to be grown. As a consequence, the growth rate suffers a significant variation just for these positions of the heater. From these considerations a plausible interpretation has been proposed to understand the apparition of solvent inclusions in the form of thin

Growth patterns for etiolated soybeans germinated under spaceflight conditions

Science.gov (United States)

Levine, Howard G.; Piastuch, William C.

In the GENEX (GENe EXpression) spaceflight experiment (flown on STS-87), six surface sterilized soybean seeds ( Glycine max cv McCall) were inserted into each of 32 autoclaved plastic seed growth pouches containing an inner germination paper sleeve (for a total of 192 seeds). The pouches were stowed within a mid-deck locker until Mission Flight Day 10, at which time an astronaut added water to initiate the process of seed germination on-orbit and subsequently transferred them to four light-tight aluminum canisters called BRIC-60s (Biological Research In Canisters). We report here on the morphological characteristics of: (1) the recovered flight plants ( N = 177), (2) the corresponding ground control population ( N = 183), plus (3) additional controls grown on the ground under clinostat conditions ( N = 93). No significant morphological differences were found between the flight, ground control and clinorotated treatments for either the cotyledons or hypocotyls. There were, however, significantly longer primary roots produced in the flight population relative to the ground control population, which in turn had significantly longer primary roots than the clinorotated population. This same pattern was observed relative to the production of lateral roots (flight > control > clinorotated). Taken together with previous literature reports, we believe that there is now sufficient evidence to conclude that plants grown under conditions of microgravity will generally exhibit enhanced root production relative to their ground control counterparts. Some causes underlying this phenomenon are speculated on.

Growth response of broiler chickens fed varying levels of sheanut cake

African Journals Online (AJOL)

The inclusion of SNC in the diet of broiler chickens at 2.5 per cent had no deleterious effect on their growth performance and also reduced cost of feeding. . Une étude de quatre semaines ( 264 de poulets de chair, de la race de Cobb ) était entreprise pour évaluer la réaction en croissance de poulets de chair aux quantités ...

Influence of Environmental Variables on Gambierdiscus spp. (Dinophyceae Growth and Distribution.

Directory of Open Access Journals (Sweden)

Yixiao Xu

Full Text Available Benthic dinoflagellates in the genus Gambierdiscus produce the ciguatoxin precursors responsible for the occurrence of ciguatera toxicity. The prevalence of ciguatera toxins in fish has been linked to the presence and distribution of toxin-producing species in coral reef ecosystems, which is largely determined by the presence of suitable benthic habitat and environmental conditions favorable for growth. Here using single factor experiments, we examined the effects of salinity, irradiance, and temperature on growth of 17 strains of Gambierdiscus representing eight species/phylotypes (G. belizeanus, G. caribaeus, G. carolinianus, G. carpenteri, G. pacificus, G. silvae, Gambierdiscus sp. type 4-5, most of which were established from either Marakei Island, Republic of Kiribati, or St. Thomas, United States Virgin Island (USVI. Comparable to prior studies, growth rates fell within the range of 0-0.48 divisions day(-1. In the salinity and temperature studies, Gambierdiscus responded in a near Gaussian, non-linear manner typical for such studies, with optimal and suboptimal growth occurring in the range of salinities of 25 and 45 and 21.0 and 32.5°C. In the irradiance experiment, no mortality was observed; however, growth rates at 55 μmol photons · m(-2 · s(-1 were lower than those at 110-400 μmol photons · m(-2 · s(-1. At the extremes of the environmental conditions tested, growth rates were highly variable, evidenced by large coefficients of variability. However, significant differences in intraspecific growth rates were typically found only at optimal or near-optimal growth conditions. Polynomial regression analyses showed that maximum growth occurred at salinity and temperature levels of 30.1-38.5 and 23.8-29.2°C, respectively. Gambierdiscus growth patterns varied among species, and within individual species: G. belizeanus, G. caribaeus, G. carpenteri, and G. pacificus generally exhibited a wider range of tolerance to environmental

Fast vertical growth of ZnO nanorods using a modified chemical bath deposition

Energy Technology Data Exchange (ETDEWEB)

Lee, Tae-hyun [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Ryu, Hyukhyun, E-mail: hhryu@inje.ac.kr [Department of Nano Systems Engineering, Center for Nano Manufacturing, Inje University, Obang-dong, Gimhae, Gyeongnam 621-749 (Korea, Republic of); Lee, Won-Jae [Department of Materials and Components Engineering, Dong-Eui University, 995 Eomgwangno, Busanjin-gu, Busan 614-714 (Korea, Republic of)

2014-06-01

Highlights: • We grew vertical ZnO nanorods by a modified CBD process with a fast growth rate. • We studied the effects of the CBD process by varying growth temperature, time, and concentration. • The ZnO nanorods grown by the modified CBD showed good morphological and structural properties. - Abstract: In this study, we grew vertical ZnO nanorods on seeded Si (1 0 0) substrates using a modified chemical bath deposition (CBD). We investigated the effects of the growth temperature, growth time and concentration on the morphological and structural properties of the ZnO nanorods using field emission gun scanning electron microscopy (FEG-SEM) and X-ray diffraction. This modified CBD method shows improved results over conventional CBD. ZnO nanorods with good structural XRD properties were grown with a very fast growth rate in a wide range of growth conditions and did not require post-growth annealing.

Design of Multijunction Photovoltaic Cells Optimized for Varied Atmospheric Conditions

Directory of Open Access Journals (Sweden)

C. Zhang

2014-01-01

Full Text Available Band gap engineering provides an opportunity to not only provide higher overall conversion efficiencies of the reference AM1.5 spectra but also customize PV device design for specific geographic locations and microenvironments based on atmospheric conditions characteristic to that particular location. Indium gallium nitride and other PV materials offer the opportunity for limited bandgap engineering to match spectra. The effects of atmospheric conditions such as aerosols, cloud cover, water vapor, and air mass have been shown to cause variations in spectral radiance that alters PV system performance due to both overrating and underrating. Designing PV devices optimized for spectral radiance of a particular region can result in improved PV system performance. This paper presents a new method for designing geographically optimized PV cells with using a numerical model for bandgap optimization. The geographic microclimate spectrally resolved solar flux for twelve representative atmospheric conditions for the incident radiation angle (zenith angle of 48.1° and fixed array angle of 40° is used to iteratively optimize the band gap for tandem, triple, and quad-layer of InGaN-based multijunction cells. The results of this method are illustrated for the case study of solar farms in the New York region and discussed.

Influence of storage conditions on the release of growth factors in platelet-rich blood derivatives

Directory of Open Access Journals (Sweden)

Düregger Katharina

2016-09-01

Full Text Available Thrombocytes can be concentrated in blood derivatives and used as autologous transplants e.g. for wound treatment due to the release of growth factors such as platelet derived growth factor (PDGF. Conditions for processing and storage of these platelet-rich blood derivatives influence the release of PDGF from the platelet-bound α-granules into the plasma. In this study Platelet rich plasma (PRP and Platelet concentrate (PC were produced with a fully automated centrifugation system. Storage of PRP and PC for 1 h up to 4 months at temperatures between −20°C and +37°C was applied with the aim of evaluating the influence on the amount of released PDGF. Storage at −20°C resulted in the highest release of PDGF in PRP and a time dependency was determined: prolonged storage up to 1 month in PRP and 10 days in PC increased the release of PDGF. Regardless of the storage conditions, the release of PDGF per platelet was higher in PC than in PRP.

Process control by optical emission spectroscopy during growth of a-C:H from a CH₄ plasma by plasma-enhanced chemical vapour deposition

DEFF Research Database (Denmark)

Barholm-Hansen, C; Bentzon, MD; Vigild, Martin Etchells

1994-01-01

During the growth of a-C:H thin films for tribological applications, the characteristic optical emission from a CH4 plasma was used to estimate growth conditions such as the degree of dissociation of the feed gas, the deposition rate and the presence of impurities. Films were fabricated with vari...

Membrane protein profiling of Acidovorax avenae subsp. avenae under various growth conditions.

Science.gov (United States)

Li, Bin; Wang, Li; Ibrahim, Muhammad; Ge, Mengyu; Wang, Yanli; Mannan, Shazia; Asif, Muhammad; Sun, Guochang

2015-06-01

Membrane proteins (MPs) of plant pathogenic bacteria have been reported to be able to regulate many essential cellular processes associated with plant disease. The aim of the current study was to examine and compare the expression of MPs of the rice bacterial pathogen Acidovorax avenae subsp. avenae strain RS-1 under Luria-Bertani (LB) medium, M9 medium, in vivo rice plant conditions and leaf extract (LE) medium mimicking in vivo plant condition. Proteomic analysis identified 95, 72, 75, and 87 MPs under LB, in vivo, M9 and LE conditions, respectively. Among them, six proteins were shared under all tested growth conditions designated as abundant class of proteins. Twenty-six and 21 proteins were expressed uniquely under in vivo versus LB medium and LE versus M9 medium, respectively, with 17 proteins common among these uniquely induced proteins. Moreover, most of the shared proteins are mainly related to energy metabolism, transport of small molecules, protein synthesis and secretion as well as virulence such as NADH, OmpA, secretion proteins. Therefore, the result of this study not only suggests that it may be an alternate method to analyze the in vivo expression of proteins by using LE medium to mimic plant conditions, but also reveals that the two sets of differentially expressed MPs, in particular the common MPs between them, might be important in energy metabolism, stress response and virulence of A. avenae subsp. avenae strain RS-1.

Comprehensive Study Of Duckweed Cultivation And Growth Conditions Under Controlled Eutrophication

Directory of Open Access Journals (Sweden)

Bartošová Alica

2015-06-01

Full Text Available The paper discussed the issue of eutrophication. The most conspicuous effect of eutrophication is the creation of dense blooms of noxious, foul-smelling phytoplankton that reduce water clarity and harm water quality. Nutrient concentration, temperature and pH of the water largely influence the growth rate and composition of duckweed in general, but it can be said that the temperature and solar irradiation are the most important factors. In order to compare the rate of biomass increase of duckweed biomass in natural conditions and in a laboratory grown sample was analysed by spectrophotometric methods in UV/VIS region (Spectrophotometer GENESYSTM for the selected nutrients such as ammonium, ammonium nitrogen, nitrite, nitrate, and phosphate.

Adaptive observer-based control for an IPMC actuator under varying humidity conditions

Science.gov (United States)

Bernat, Jakub; Kolota, Jakub

2018-05-01

As ionic polymer metal composites (IPMC) are increasingly applied to mechatronic systems, many new IPMC modeling efforts have been reported in the literature. The demands of rapidly growing technology has generated interest in advancing the intrinsic actuation and sensing capabilities of IPMC. Classical IPMC applications need constant hydration to operate. On the other hand, for IPMCs operating in air, the water content of the polymer varies with the humidity level of the ambient environment, which leads to its strong humidity-dependent behavior. Furthermore, decreasing water content over time plays a crucial role in the effectiveness of IPMC. Therefore, the primary challenge of this work is to accurately model this phenomenon. The principal contribution of the paper is a new IPMC model, which considers the change of moisture content. A novel nonlinear adaptive observer is designed to determine the unknown electric potential and humidity level in the polymer membrane. This approach effectively determines the moisture content of the IPMC during long-term continuous operation in air. This subsequently allows us to develop an effective back-stepping control algorithm that considers varying moisture content. Data from experiments are presented to support the effectiveness of the observation process, which is shown in illustrative examples.

Deep Soil Conditions Make Mediterranean Cork Oak Stem Growth Vulnerable to Autumnal Rainfall Decline in Tunisia

Directory of Open Access Journals (Sweden)

Lobna Zribi

2016-10-01

Full Text Available Tree rings provide fruitful information on climate features driving annual forest growth through statistical correlations between annual tree growth and climate features. Indices built upon tree growth limitation by carbon sequestration (source hypothesis or drought-driven cambial phenology (sink hypothesis can be used to better identify underlying processes. We used both analytical frameworks on Quercus suber, a sparsely studied species due to tree ring methodological issues, and growing on a favorable sub-humid Mediterranean climate and deep soil conditions in Tunisia (North Africa. Statistical analysis revealed the major role of autumnal rainfall before the growing season on annual tree growth over the 1918–2008 time series. Using a water budget model, we were able to explain the critical role of the deep soil water refill during the wet season in affecting both the drought onset controlling growth phenology and the summer drought intensity affecting carbon assimilation. Analysis of recent climate changes in the region additionally illustrated an increase in temperatures enhancing the evaporative demand and advancing growth start, and a decline in rainfalls in autumn, two key variables driving stem growth. We concluded on the benefits of using process-based indices in dendrochronological analysis and identified the main vulnerability of this Mediterranean forest to autumnal rainfall decline, a peculiar aspect of climate change under summer-dry climates.

In Vitro Seeds Germination and Seedling Growth of Bambara Groundnut (Vigna subterranea (L.) Verdc. (Fabaceae)).

Science.gov (United States)

Koné, Mongomaké; Koné, Tchoa; Silué, Nakpalo; Soumahoro, André Brahima; Kouakou, Tanoh Hilaire

2015-01-01

Bambara groundnut (Vigna subterranea (L.) Verdc.) is an indigenous grain legume. It occupies a prominent place in the strategies to ensure food security in sub-Saharan Africa. Development of an efficient in vitro regeneration system, a prerequisite for genetic transformation application, requires the establishment of optimal conditions for seeds germination and plantlets development. Three types of seeds were inoculated on different basal media devoid of growth regulators. Various strengths of the medium of choice and the type and concentration of carbon source were also investigated. Responses to germination varied with the type of seed. Embryonic axis (EA) followed by seeds without coat (SWtC) germinated rapidly and expressed a high rate of germination. The growth performances of plantlets varied with the basal medium composition and the seeds type. The optimal growth performances of plants were displayed on half strength MS basal medium with SWtC and EA as source of seeds. Addition of 3% sucrose in the culture medium was more suitable for a maximum growth of plantlets derived from EA.

Abscisic acid regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin.

Science.gov (United States)

Rowe, James H; Topping, Jennifer F; Liu, Junli; Lindsey, Keith

2016-07-01

Understanding the mechanisms regulating root development under drought conditions is an important question for plant biology and world agriculture. We examine the effect of osmotic stress on abscisic acid (ABA), cytokinin and ethylene responses and how they mediate auxin transport, distribution and root growth through effects on PIN proteins. We integrate experimental data to construct hormonal crosstalk networks to formulate a systems view of root growth regulation by multiple hormones. Experimental analysis shows: that ABA-dependent and ABA-independent stress responses increase under osmotic stress, but cytokinin responses are only slightly reduced; inhibition of root growth under osmotic stress does not require ethylene signalling, but auxin can rescue root growth and meristem size; osmotic stress modulates auxin transporter levels and localization, reducing root auxin concentrations; PIN1 levels are reduced under stress in an ABA-dependent manner, overriding ethylene effects; and the interplay among ABA, ethylene, cytokinin and auxin is tissue-specific, as evidenced by differential responses of PIN1 and PIN2 to osmotic stress. Combining experimental analysis with network construction reveals that ABA regulates root growth under osmotic stress conditions via an interacting hormonal network with cytokinin, ethylene and auxin. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Interactive effects of temperature and light during deep convection: a case study on growth and condition of the diatom Thalassiosira weissflogii

DEFF Research Database (Denmark)

Walter, B.; Peters, J.; van Beusekom, J. E. E.

2015-01-01

pulses of a higher light intensity (120 mmol m22 s21, 2/22 hlight/dark). Both experimental light conditions offered the same daily light dose. No growth was observed at temperatures below 88C. Above 88C, growth rates were significantly higher under low light conditions compared with those of short pulsed...... light exposures, indicating a higher efficiency of light utilization. This could be related to (i) a higher content of Chl a per cell in the lowlight trial and/or (ii) a more efficient transfer of light energy into growth as indicated by constantly low carbohydrate levels.In contrast, pulsed intense...... did not provide sufficient light to reach full light saturation. In general, photosynthesis was more strongly affected by temperature under pulsed light than under low light conditions. Our results indicate that model estimates of primary production in relation to deep convection, which are based...

Canopy structure and tree condition of young, mature, and old-growth Douglas-fir/hardwood forests

Science.gov (United States)

B.B. Bingham; J.O. Sawyer

1992-01-01

Sixty-two Douglas-fir/hardwood stands ranging from 40 to 560 years old were used to characterize the density; diameter, and height class distributions of canopy hardwoods and conifers in young (40 -100 yr), mature (101 - 200 yr) and old-growth (>200 yr) forests. The crown, bole, disease, disturbance, and cavity conditions of canopy conifers and hardwoods were...

Assessment of Salmonella spp. and Escherichia coli O157:H7 growth on lettuce exposed to isothermal and non-isothermal conditions.

Science.gov (United States)

de Oliveira Elias, Susana; Noronha, Tiago Baptista; Tondo, Eduardo Cesar

2018-06-01

This study aimed to assess the growth of Salmonella and Escherichia coli O157:H7 on lettuce exposed to isothermal and non-isothermal conditions. Pathogens were inoculated on lettuce separately and stored under isothermal condition at 5 °C, 10 °C, 25 °C, 37 °C for both bacteria, at 40 °C for Salmonella and 42 °C for E. coli O157:H7. Growth curves were built by fitting the data to the Baranyi's DMFit, generating R 2 values greater than 0.92 for primary models. Secondary models were fitted with Ratkowsky equations, generating R 2 values higher than 0.91 and RMSE lower than 0.1. Experimental data showed that both bacteria could grow at all temperatures. Also, the growth of both pathogens under non-isothermal conditions was studied simulating temperatures found from harvest to supermarkets in Brazil. Models were analysed by R 2 , RMSE, bias factor (Bf) and accuracy factor (Af). Salmonella and E. coli O157:H7 were able to grow in this temperature profile and the models could predict the behavior of these microorganisms on lettuce under isothermal and non-isothermal conditions. Based on the results, a negligible growth time (ς) was proposed to provide the time which lettuce could be exposed to a specific temperature and do not present an expressive growth of bacteria. The ς was developed based on Baranyi's primary model equation and on growth potential concept. ς is the value of lag phase added of the time necessary to population grow 0.5 log CFU/g. The ς of lettuce exposed to 37 °C was 1.3 h, while at 5 °C was 3.3 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

Varying temperature and silicon content in nanodiamond growth: effects on silicon-vacancy centres.

Science.gov (United States)

Choi, Sumin; Leong, Victor; Davydov, Valery A; Agafonov, Viatcheslav N; Cheong, Marcus W O; Kalashnikov, Dmitry A; Krivitsky, Leonid A

2018-02-28

Nanodidamonds containing colour centres open up many applications in quantum information processing, metrology, and quantum sensing. However, controlling the synthesis of nanodiamonds containing silicon vacancy (SiV) centres is still not well understood. Here we study nanodiamonds produced by a high-pressure high-temperature method without catalyst metals, focusing on two samples with clear SiV signatures. Different growth temperatures and relative content of silicon in the initial compound between the samples altered their nanodiamond size distributions and abundance of SiV centres. Our results show that nanodiamond growth can be controlled and optimised for different applications.

Fecundity, survival, and growth of the seahorse Hippocampus ingens (Pisces: Syngnathidae under semi-controlled conditions

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A.A Ortega-Salas

2006-12-01

Full Text Available Estudiamos la fecundidad, supervivencia, y crecimiento del caballito de mar, Hippocampus ingens en condiciones semi-controladas. Tres machos reproductores silvestres de 14.8, 24.5 y 32.0 g produjeron 1 598, 1 703 y 1 658 jóvenes. La densidad utilizada fue de 12 jóvenes por acuario de 60 l. Se agruparon en 1, 12 y 20 días de nacidos por acuario. La supervivencia fue de 78.5, 38.1 y 41.0 % en 35 días. Se les alimentó con una mezcla de rotíferos B. plicatilis y nauplios de Artemia para después transferirlos a estanques de 100 000 l a una densidad de 50/1 000 l, donde se les alimentó con Artemia adulta durante 60 días más. Crecieron de un promedio de 0.7, 1.5, y 2.7 a 4.5, 5.4 6.7 cm, respectivamente, en 95 días. La temperatura del agua marina utilizada varió de 17 a 23 ºC.We studied fecundity, survival, and growth of the seahorse Hippocampus ingens under semi-controlled conditions. Three wild brood stock mature males of 14.8, 24.5, and 32.0 g released 1 598, 1 703, and 1 658 juveniles. Juvenile stocking densities of 12 were settled in 60-l aquariums in groups of 1, 12, and 20 days old organisms. The rate of survival was 21.5, 61.9, and 59.0 %, respectively, in 35 days. Juveniles were fed a mix diet of rotifers B. plicatilis and Artemia nauplii, then they were transferred to a cement tank of 100 000 l at a density of 50/1 000 l and fed with live adult Artemia for 60 days more. They grew from an average of 0.7, 1.5, and 2.7 to 4.5, 5.4, and 6.7 cm, respectively, in 95 days. The seawater temperature varied from 17 to 23 ºC. Rev. Biol. Trop. 54 (4: 1099-1102. Epub 2006 Dec. 15.

Preincubation of Penicillium commune conidia under modified atmosphere conditions: Influence on growth potential as determined by an impedimetric method

DEFF Research Database (Denmark)

Haasum, Iben; Nielsen, Per Væggemose

1996-01-01

The combined effect of preincubation time, relative humidity (r.h.), headspace carbon dioxide (CO2) and oxygen (O2) on subsequent growth potential of conidia from Penicillium commune was studied using Response Surface Modelling (RSM). Native conidia were preincubated under modified atmosphere...... conditions in sealed vials for 14, 35 and 56 d. Lag time and growth rates were determined using impedance microbiology on a Bactometer. Conidia survived and some swelling was observed during all experimental preincubation conditions. Regression analysis of the subsequent growth responses showed that relative...... humidity in the vials was the most significant factor affecting lag time of the conidia after preincubation for 14 and 35 d. Storage for 35 d extended lag times by 15 h when the level of r.h. was increased from 41% to 80%. After prolonged storage (56 d) r.h and CO2 levels elicited a significant effect...

Dynamics in copy numbers of five plasmids of a dairy Lactococcus lactis in dairy-related conditions including near-zero growth rates.

Science.gov (United States)

van Mastrigt, Oscar; Lommers, Marcel M A N; de Vries, Yorick C; Abee, Tjakko; Smid, Eddy J

2018-03-23

Lactic acid bacteria can carry multiple plasmids affecting their performance in dairy fermentations. The expression of plasmid-encoded genes and the activity of the corresponding proteins is severely affected by changes in the number of plasmid copies. We studied the impact of growth rate on dynamics of plasmid copy numbers at high growth rates in chemostat cultures and down to near-zero growth rates in retentostat cultures. Five plasmids of the dairy strain Lactococcus lactis FM03-V1 were selected which varied in size (3 to 39 kb), in replication mechanism (theta or rolling-circle) and in putative (dairy-associated) functions. Copy numbers ranged from 1.5 to 40.5 and the copy number of theta-type replicating plasmids were negatively correlated to the plasmid size. Despite the extremely wide range of growth rates (0.0003 h -1 to 0.6 h -1 ), copy numbers of the five plasmids were stable and only slightly increased at near-zero growth rates showing that the plasmid replication rate was strictly controlled. One low-copy number plasmid, carrying a large exopolysaccharide gene cluster, was segregationally unstable during retentostat cultivations reflected in complete loss of the plasmid in one of the retentostat cultures. The copy number of the five plasmids was also hardly affected by varying the pH value, nutrient limitation or presence of citrate (maximum 2.2-fold) signifying the stability in copy number of the plasmids. Importance Lactococcus lactis is extensively used in starter cultures for dairy fermentations. Important traits for growth and survival of L. lactis in dairy fermentations are encoded by genes located on plasmids, such as genes involved in lactose and citrate metabolism, protein degradation and oligopeptide uptake and bacteriophage resistance. Because the number of plasmid copies could affect the expression of plasmid-encoded genes, it is important to know the factors that influence the plasmid copy numbers. We monitored plasmid copy numbers of L

Nitrogen-Utilization by Plant-Species from Acid Heathland Soils .2. Growth and Shoot/Root Partitioning of No3- Assimilation at Constant Low Ph and Varying No3-/Nh4+ Ratio

NARCIS (Netherlands)

Troelstra, S.R.; Wagenaar, R.; Smant, W.

1995-01-01

The growth of four heathland species, two grasses (D. flexuosa, M. caerulea) and two dwarf shrubs (C. vulgaris, E. tetralix), was tested in solution culture at pH 4.0 with 2 mol m(-3) N, varying the NO3-/NH4+ ratio up to 40% nitrate. In addition, measurements of NRA, plant chemical composition, and

Research on crystal growth by using pressure as a control parameter; Atsuryoku seigyo ni yoru kessho seicho ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-10-31

This research project aims to establish a technique for crystal growth using pressure as a principal control parameter, and combining it with a microgravity condition, to develop a novel process material fabrication. Since the solubility of materials depends on pressure, it is possible to control a supersaturated condition for crystal growth by changing pressure. The growth condition can be controlled precisely, which is not possible by conventional methods that vary temperature and other factors. On the other hand, because a concentration diffusing field is formed autonomically around crystals in association with their growth, density convection is generated under gravity as a result of difference in the concentrations, making the growth conditions severely complex and uncontrollable. Ideal crystal growth condition control may be possible if the pressure control is performed under micro-gravity by which generation of the density convection can be suppressed. Realization has been achieved on in-situ observation by using high-magnification microscope which uses a diamond anvil cell, development of a hydraulic type optic pressure cell, and a high- speed crystal growing technology by means of pressure control utilizing the cell. New findings were also obtained on effects of pressure on crystal forms, and the pressure induced solid phase transfer mechanism. 67 refs., 49 figs., 3 tabs.

An investigation into the stability of commercial versus MG63-derived hepatocyte growth factor under flow cultivation conditions.

Science.gov (United States)

Meneghello, Giulia; Storm, Michael P; Chaudhuri, Julian B; De Bank, Paul A; Ellis, Marianne J

2015-03-01

The scale-up of tissue engineering cell culture must ensure that conditions are maintained while also being cost effective. Here we analyse the stability of hepatocyte growth factor (HGF) to investigate whether concentrations change under dynamic conditions, and compare commercial recombinant human HGF as an additive in 'standard medium', to HGF secreted by the osteosarcoma cell line MG63 as a 'preconditioned medium'. After 3 h under flow conditions, HGF in the standard medium degraded to 40% of its original concentration but HGF in the preconditioned medium remained at 100%. The concentration of secreted HGF was 10 times greater than the working concentration of commercially-available HGF. Thus HGF within this medium has increased stability; MG63-derived HGF should therefore be investigated as a cost-effective alternative to current lyophilised powders for use in in vitro models. Furthermore, we recommend that those intending to use HGF (or other growth factors) should consider similar stability testing before embarking on experiments with media flow.

The influence of antioxidants 'TIOFAN' and 'FANTOX 11-1' on physiological growth of broilers in conditions of intoxication with lead and cadmium salts

International Nuclear Information System (INIS)

Koval, Yu.I.; Bokova, T.I.; Kandalintseva, N.V.

2008-01-01

The purpose of research is to study the influence of antioxidants 'TIOFAN' and 'FANTOX 11-1' on physiological growth of broilers in conditions of intoxication with lead and cadmium salts. The growth and development of bird in conditions of intoxication with heavy metals and by using of antioxidants as detoxicant is studied. The biochemical blood values on application of antioxidants and without them in conditions of intoxication are determined. The most effective preparation raising of birds productivity and it's optimal concentration is established.

Generic conditions for suppressing the coherent synchrotron radiation induced emittance growth in a two-dipole achromat

Science.gov (United States)

Jiao, Yi; Cui, Xiaohao; Huang, Xiyang; Xu, Gang

2014-06-01

The effect of the coherent synchrotron radiation (CSR) becomes evident, and leads to increased beam energy spread and transverse emittance dilution, as both the emittance and bunch length of the electron beams are continuously pushed down in present and forthcoming high-brightness light sources and linear colliders. Suppressing this effect is important to preserve the expected machine performance. Methods of the R-matrix analysis and the Courant-Snyder formalism analysis have been proposed to evaluate and to suppress the emittance growth due to CSR in achromatic cells. In this paper a few important modifications are made on these two methods, which enable us to prove that these two methods are equivalent to each other. With the modified analysis, we obtain explicit and generic conditions of cancelling the CSR-driven emittance excitation in a single achromat consisting of two dipoles of arbitrary bending angles. In spite of the fact that the analysis constrains itself in a linear regime, based on the assumption that CSR-induced particle energy deviation is proportional to both θ and ρ1/3, with θ being the bending angle and ρ the bending radius, it is demonstrated through ELEGANT simulations that the conditions derived from this analysis are still effective in suppressing the emittance growth when a more detailed one-dimensional CSR model is considered. In addition, it illustrates that the emittance growth can be reduced to a lower level with the proposed conditions than with the other two approaches, such as matching the beam envelope to the CSR kick and setting the cell-to-cell betatron phase advance to an appropriate value.

Seedling growth in greenhouse conditions of the forest species Dialium guianense (Aubl. Sandwith

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Georgina Vargas Simon

2018-01-01

Full Text Available Dialium guianense is used for its wood and fruit production, and is a tropical tree species native to evergreen forests. Given the threat these forests face, the purpose of this work was to evaluate the initial growth of the plant under greenhouse conditions, for aiming in the development of propagation programs. Seedlings of the species were transplanted to nursery bags under a completely randomized design and grown for 10 months with an initial population of 200 plants. At the end of the experiment, the shoot and root reached lengths of 32.8 and 28.9 cm, respectively. The average number of composite leaves was 12.3 each with seven leaflets. The average biomass was 2.5 g for the shoot, 1.6 g for roots, and 3.7 g for leaves, with a shoot/root around four. The average relative growth rate (RGR was 15 mg g-1 day-. These characteristics indicate that D. guianense is a late successional species.

Importance of interactions between food quality, quantity, and gut transit time on consumer feeding, growth, and trophic dynamics.

Science.gov (United States)

Mitra, Aditee; Flynn, Kevin J

2007-05-01

Ingestion kinetics of animals are controlled by both external food availability and feedback from the quantity of material already within the gut. The latter varies with gut transit time (GTT) and digestion of the food. Ingestion, assimilation efficiency, and thus, growth dynamics are not related in a simple fashion. For the first time, the important linkage between these processes and GTT is demonstrated; this is achieved using a biomass-based, mechanistic multinutrient model fitted to experimental data for zooplankton growth dynamics when presented with food items of varying quality (stoichiometric composition) or quantity. The results show that trophic transfer dynamics will vary greatly between the extremes of feeding on low-quantity/high-quality versus high-quantity/low-quality food; these conditions are likely to occur in nature. Descriptions of consumer behavior that assume a constant relationship between the kinetics of grazing and growth irrespective of food quality and/or quantity, with little or no recognition of the combined importance of these factors on consumer behavior, may seriously misrepresent consumer activity in dynamic situations.

Weed Growth Stage Estimator Using Deep Convolutional Neural Networks.

Science.gov (United States)

Teimouri, Nima; Dyrmann, Mads; Nielsen, Per Rydahl; Mathiassen, Solvejg Kopp; Somerville, Gayle J; Jørgensen, Rasmus Nyholm

2018-05-16

This study outlines a new method of automatically estimating weed species and growth stages (from cotyledon until eight leaves are visible) of in situ images covering 18 weed species or families. Images of weeds growing within a variety of crops were gathered across variable environmental conditions with regards to soil types, resolution and light settings. Then, 9649 of these images were used for training the computer, which automatically divided the weeds into nine growth classes. The performance of this proposed convolutional neural network approach was evaluated on a further set of 2516 images, which also varied in term of crop, soil type, image resolution and light conditions. The overall performance of this approach achieved a maximum accuracy of 78% for identifying Polygonum spp. and a minimum accuracy of 46% for blackgrass. In addition, it achieved an average 70% accuracy rate in estimating the number of leaves and 96% accuracy when accepting a deviation of two leaves. These results show that this new method of using deep convolutional neural networks has a relatively high ability to estimate early growth stages across a wide variety of weed species.

Brane world cosmologies with varying speed of light

International Nuclear Information System (INIS)

Youm, Donam

2001-02-01

We study cosmologies in the Randall-Sundrum models, incorporating the possibility of time-varying speed of light and Newton's constant. The cosmologies with varying speed of light (VSL) were proposed by Moffat and by Albrecht and Magueijo as an alternative to inflation for solving the cosmological problems. We consider the case in which the speed of light varies with time after the radion or the scale of the extra dimension has been stabilized. We elaborate on the conditions under which the flatness problem and the cosmological constant problem can be resolved. Particularly, the VSL cosmologies may provide a possible mechanism for bringing the quantum corrections to the fine-tuned brane tensions after the SUSY breaking under control. (author)

Salmonella Modulates Metabolism During Growth under Conditions that Induce Expression of Virulence Genes

Energy Technology Data Exchange (ETDEWEB)

Kim, Young-Mo; Schmidt, Brian; Kidwai, Afshan S.; Jones, Marcus B.; Deatherage, Brooke L.; Brewer, Heather M.; Mitchell, Hugh D.; Palsson, Bernhard O.; McDermott, Jason E.; Heffron, Fred; Smith, Richard D.; Peterson, Scott N.; Ansong, Charles; Hyduke, Daniel R.; Metz, Thomas O.; Adkins, Joshua N.

2013-04-05

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a facultative pathogen that uses complex mechanisms to invade and proliferate within mammalian host cells. To investigate possible contributions of metabolic processes in S. Typhimurium grown under conditions known to induce expression of virulence genes, we used a metabolomics-driven systems biology approach coupled with genome scale modeling. First, we identified distinct metabolite profiles associated with bacteria grown in either rich or virulence-inducing media and report the most comprehensive coverage of the S. Typhimurium metabolome to date. Second, we applied an omics-informed genome scale modeling analysis of the functional consequences of adaptive alterations in S. Typhimurium metabolism during growth under our conditions. Excitingly, we observed possible sequestration of metabolites recently suggested to have immune modulating roles. Modeling efforts highlighted a decreased cellular capability to both produce and utilize intracellular amino acids during stationary phase culture in virulence conditions, despite significant abundance increases for these molecules as observed by our metabolomics measurements. Model-guided analysis suggested that alterations in metabolism prioritized other activities necessary for pathogenesis instead, such as lipopolysaccharide biosynthesis.

Effect of indium accumulation on the characteristics of a-plane InN epi-films under different growth conditions

Energy Technology Data Exchange (ETDEWEB)

Lo, Yun-Yo [Institute of Photonics, National Changhua University of Education, Changhua, Taiwan, ROC (China); Huang, Man-Fang, E-mail: mfhuang@cc.ncue.edu.tw [Institute of Photonics, National Changhua University of Education, Changhua, Taiwan, ROC (China); Chiang, Yu-Chia [Institute of Photonics, National Changhua University of Education, Changhua, Taiwan, ROC (China); Fan, Jenn-Chyuan [Department of Electronic Engineering, Nan Kai University of Technology, Nantou, Taiwan, ROC (China)

2015-08-31

This study investigated the influence of indium accumulation happened on the surface of a-plane InN grown under different growth conditions. Three different growth rates with N/In ratio from stoichiometric to N-rich were used to grow a-plane InN epifilms on GaN-buffered r-plane sapphires by plasma-assisted molecular beam epitaxy. When a-plane InN was grown above 500 °C with a high growth rate, abnormally high in-situ reflectivity was found during a-plane InN growth, which was resulted from indium accumulation on surface owing to In-N bonding difficulty on certain crystal faces of a-plane InN surface. Even using excess N-flux, indium accumulation could still be found in initial growth and formed 3-dimension-like patterns on a-plane InN surface which resulted in rough surface morphology. By reducing growth rate, surface roughness was improved because indium atoms could have more time to migrate to suitable position. Nonetheless, basal stacking fault density and crystal anisotropic property were not affected by growth rate. - Highlights: • High growth temperature could cause indium accumulation on a-plane InN surface. • Indium accumulation on a-plane InN surface causes rough surface. • Low growth rate improves surface morphology but not crystal quality.

Effect of cultivation conditions on growth and antifungal activity of ...

African Journals Online (AJOL)

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Growth and production of antifungal agent by Mycena leptocephala was investigated in different culture media composition at various initial pH and temperatures. Maximum growth and activity was observed at the initial pH of 5.5 and 25oC. No detectable growth and activity was observed at pH of 3.5 and 7.5. Growth of the ...

Plasticity of Streptomyces coelicolor membrane composition under different growth conditions and during development

Directory of Open Access Journals (Sweden)

Mario eSandoval-Calderón

2015-12-01

Full Text Available Streptomyces coelicolor is a model actinomycete that is well known for the diversity of its secondary metabolism and its complex life cycle. As a soil inhabitant, it is exposed to heterogeneous and frequently changing environmental circumstances. In the present work, we studied the effect of diverse growth conditions and phosphate depletion on its lipid profile and the relationship between membrane lipid composition and development in S. coelicolor. The lipid profile from cultures grown on solid media, which is closer to the natural habitat of this microorganism, does not resemble the previously reported lipid composition from liquid grown cultures of S. coelicolor. Wide variations were also observed across different media, growth phases, and developmental stages indicating active membrane remodeling. Ornithine lipids (OL are phosphorus-free polar lipids that were accumulated mainly during sporulation stages, but were also major components of the membrane under phosphorus limitation. In contrast, phosphatidylethanolamine, which had been reported as one of the major polar lipids in the genus Streptomyces, is almost absent under these conditions. We identified one of the genes responsible for the synthesis of OL (SCO0921 and found that its inactivation causes the absence of OL, precocious morphological development and actinorhodin production. Our observations indicate a remarkable plasticity of the membrane composition in this bacterial species, reveal a higher metabolic complexity than expected, and suggest a relationship between cytoplasmic membrane components and the differentiation programs in S. coelicolor.

Effect of mycorrhizas application on plant growth and nutrient uptake in cucumber production under field conditions

Energy Technology Data Exchange (ETDEWEB)

Ortas, I.

2010-07-01

Mycorrhizas application in horticultural production in the Eastern Mediterranean region of Turkey has been studied under field conditions for several years. The effects of different arbuscular mycorrhizal fungi (AMF) have been evaluated under field conditions for cucumber production. The parameters measured were seedling survival, plant growth and yield, and root colonization. In 1998 and 1999, Glomus mosseae and Glomus etunicatum inoculated cucumber seedlings were treated with and without P (100 kg P2O5 ha-1) application. A second experiment was set up to evaluate the response of cucumber to the inoculation with a consortia of indigenous mycorrhizae, G. mosseae, G. etunicatum, Glomus clarum, Glomus caledonium and a mixture of these four species. Inoculated and control non inoculated cucumber seedlings were established under field conditions in 1998, 2001, 2002 and 2004. Seedling quality, seedling survival under field conditions and yield response to mycorrhiza were tested. Fruits were harvested periodically; at blossom, plant leaves and root samples were taken for nutrient content and mycorrhizal colonization analysis respectively. The field experiment results showed that mycorrhiza inoculation significantly increased cucumber seedling survival, fruit yield, P and Zn shoot concentrations. Indigenous mycorrhiza inoculum was successful in colonizing plant roots and resulted in better plant growth and yield. The relative effectiveness of each of the inocula tested was not consistent in the different experiments, although inoculated plants always grew better than control no inoculated. The most relevant result for growers was the increased survival of seedlings. (Author) 20 refs.

The effect of plant growth-promoting rhizobacteria on asparagus seedlings and germinating seeds subjected to water stress under greenhouse conditions.

Science.gov (United States)

Liddycoat, Scott M; Greenberg, Bruce M; Wolyn, David J

2009-04-01

Plant growth-promoting rhizobacteria (PGPR) can have positive effects on vigour and productivity, especially under stress conditions. In asparagus (Asparagus officinalis L.) field culture, seeds are planted in high-density nurseries, and 1-year-old crowns are transplanted to production fields. Performance can be negatively affected by water stress, transplant shock, and disease pressure on wounded roots. PGPR inoculation has the potential to alleviate some of the stresses incurred in the production system. In this study, the effects of PGPR (Pseudomonas spp.) treatment were determined on 3-week-old greenhouse-grown seedlings and germinating seeds of 2 asparagus cultivars. The pots were irrigated to a predetermined level that resulted in optimum growth or the plants were subjected to drought or flooding stress for 8 weeks. The cultivars responded differently to PGPR: single inoculations of seedlings enhanced growth of 'Guelph Millennium' under optimum conditions and 'Jersey Giant' seedlings under drought stress. Seed inoculations with PGPR resulted in a positive response only for 'Guelph Millennium', for which both single or multiple inoculations enhanced plant growth under drought stress.

[The process of heme synthesis in bone marrow mesenchymal stem cells cultured under fibroblast growth factor bFGF and hypoxic conditions].

Science.gov (United States)

Poleshko, A G; Lobanok, E S; Mezhevikina, L M; Fesenko, E E; Volotkovskiĭ, I D

2014-01-01

It was demonstrated that fibroblast growth factor bFGF influences the process of heme synthesis, the proliferation activity and viability of bone marrow mesenchymal stem cells in culture under hypoxic conditions. The addition of fibroblast growth factor bFGF (7 ng/ml) to the medium under above conditions led to the accumulation of aminolevulinic acid--an early porphyrin and heme precursor, an increase in CD 71 expression--a transferrin receptor, and also a decrease in porphyrin pigments and heme contents--a late precursor and end products of heme synthesis, respectively. It was found that cultivation of the cells under hypoxic conditions and bFGF is an optimum to maintain high viability and proliferation capacity of the mesenchymal stem cells.

Individual Differences in the Expression of Conditioned Fear Are Associated with Endogenous Fibroblast Growth Factor 2

Science.gov (United States)

Graham, Bronwyn M.; Richardson, Rick

2016-01-01

These experiments examined the relationship between the neurotrophic factor fibroblast growth factor 2 (FGF2) and individual differences in the expression of conditioned fear. Experiments 1 and 2 demonstrated that rats naturally expressing low levels of contextual or cued fear have higher levels of hippocampal FGF2 relative to rats that express…

Individual-Tree Diameter Growth Models for Mixed Nothofagus Second Growth Forests in Southern Chile

Directory of Open Access Journals (Sweden)

Paulo C. Moreno

2017-12-01

Full Text Available Second growth forests of Nothofagus obliqua (roble, N. alpina (raulí, and N. dombeyi (coihue, known locally as RORACO, are among the most important native mixed forests in Chile. To improve the sustainable management of these forests, managers need adequate information and models regarding not only existing forest conditions, but their future states with varying alternative silvicultural activities. In this study, an individual-tree diameter growth model was developed for the full geographical distribution of the RORACO forest type. This was achieved by fitting a complete model by comparing two variable selection procedures: cross-validation (CV, and least absolute shrinkage and selection operator (LASSO regression. A small set of predictors successfully explained a large portion of the annual increment in diameter at breast height (DBH growth, particularly variables associated with competition at both the tree- and stand-level. Goodness-of-fit statistics for this final model showed an empirical coefficient of correlation (R2emp of 0.56, relative root mean square error of 44.49% and relative bias of −1.96% for annual DBH growth predictions, and R2emp of 0.98 and 0.97 for DBH projection at 6 and 12 years, respectively. This model constitutes a simple and useful tool to support management plans for these forest ecosystems.

Growth and physiological responses to varied environments among populations of Pinus ponderosa

Science.gov (United States)

Jianwei Zhang; Bert M. Cregg

2005-01-01

We investigated population responses in physiology, morphology, and growth of mature Pinus ponderosa trees to an environmental gradient across Nebraska, USA. Ten populations from western Nebraska and eastern Wyoming were grown in three 26-year-old provenance tests from the warmest and wettest site in the east (Plattsmouth) to the intermediate site in...

Comparison of Red-Cockaded Woodpecker (Piciodes borealis) Nestling Diet in Old-Growth and Old-Field Longleaf Pine (Pinus palustris)

Energy Technology Data Exchange (ETDEWEB)

Hanula, J.L.; Engstrom, R.T.

1999-10-01

Automatic cameras were used to record adult woodpecker diets in old-growth and old-field longleaf pine in the South. Roaches were the number one prey for the woodpeckers based on either biomass or numbers. The latter ranged from 37% to 57% of the prey numbers and 55%-73% of the biomass. Morisita's index of similarity between old-field and old growth varied from 0.89 to 0.95. The authors conclude that the prey base is similar in both conditions and that old-growth provides similar foraging habitat.

Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth

Directory of Open Access Journals (Sweden)

JUAN eMORAL

2015-06-01

Full Text Available Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt and the type of water stress (matric or osmotic on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30ºC during both periods, with a maximum around 20ºC. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche spp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth.

Science.gov (United States)

Moral, Juan; Lozano-Baena, María Dolores; Rubiales, Diego

2015-01-01

Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt) and the type of water stress (matric or osmotic) on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30°C during both periods, with a maximum around 20°C. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche sp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

Age, growth and fecundity of the silver mullet, Mugil curema (Pisces: Mugilidae, in coastal areas of Northeastern Venezuela

Directory of Open Access Journals (Sweden)

Baumar J Marin E

2000-06-01

Full Text Available We studied the fecundity and growth in populations of the silver mullet, Mugil curema, in coastal areas of northeastern Venezuela between March 1992 and July 1993. The average number of ovocytes in gonads of 23-42 cm adults was 54 x 104, and the relative fecundity was 1311 ovocytes g-1 of fish. The size of mature ovocytes did not vary in different portions of the same gonad (p 0.05 or among the adults in three populations studied. The average egg diameter for adults was 426 µm (CI= 4.34. Age of juveniles, collected from the La Restinga Lagoon at about monthly intervals, from counts of growth lines on the otoliths ranged from 50 to 240 days. The relation of age (number of growth lines to standard length follows an exponential growth curve. The growth of juveniles varied seasonally and was greatest during the rainy season (April to August, when temperatures were highest. The time of spawning has probably been adapted so that peak recruitment into the lagoons occurs just prior to the rainy season when conditions for growth are most favorable.

Impact of nitrogen rates on growth, yield and radiation use efficiency of maize under varying environments

International Nuclear Information System (INIS)

Khaliq, T.; Ahmad, A.; Hussain, A.

2008-01-01

Growth, yield and radiation use efficiency (RUE) of hybrid maize, in response to different nitrogen rates (150, 200, 250, 300, 350 kg ha/sub -1/ were analyzed for three different locations (Faisalabad, Sargodha and Sahiwal) in Punjab, Pakistan during 2004 and 2005. The results depicted a large yearly variations mainly attributed to more rainfall and incidence of solar radiation in 2005. Maize hybrids respond differently for all variable under study, at all sites except IPAR and radiation use efficiency 919 at different locations. Similar types of differences were noted in GGR and Final TOM. Increasing nitrogen rates had significant effects on CGR, final TOM and grain yield and RUE. The intercepted PAR, RUE/sub TDM/ and RUE/sub Gy/ were significantly affected by hybrid potential and nitrogen application rates. On an average RUE/sub TDM/ varied from 2.45 to 2.73 g MJ/sup -1/ at different locations, while RUE/sub Gy/ was recorded 1.12, 1.14 and 1.03 for Faisalabad, Sargodha and Sahiwal, respectively. Total dry matter and grain yield of different treatments was linearly related to IPAR at all location and the common regression (R/sup 2/) accounted for 94, 68, and 80 % for TDM and 64, 34, and 95% for grain yield at the Faisalabad, Sargodha and sahiwal, respectively. It was concluded that planting of hybrid Bemasal-202 with 300 kg N ha/sup -1/ is the best recommendation for semi-arid areas of Pakistan. (author)

Characteristics of bacterial and fungal growth in plastic bottled beverages under a consuming condition model.

Science.gov (United States)

Watanabe, Maiko; Ohnishi, Takahiro; Araki, Emiko; Kanda, Takashi; Tomita, Atsuko; Ozawa, Kazuhiro; Goto, Keiichi; Sugiyama, Kanji; Konuma, Hirotaka; Hara-Kudo, Yukiko

2014-01-01

Microbial contamination in unfinished beverages can occur when drinking directly from the bottle. Various microorganisms, including foodborne pathogens, are able to grow in these beverages at room temperature or in a refrigerator. In this study, we elucidated the characteristics of microorganism growth in bottled beverages under consuming condition models. Furthermore, we provide insight into the safety of partially consumed bottled beverages with respect to food hygiene. We inoculated microorganisms, including foodborne pathogens, into various plastic bottled beverages and analysed the dynamic growth of microorganisms as well as bacterial toxin production in the beverages. Eight bottled beverage types were tested in this study, namely green tea, apple juice drink, tomato juice, carbonated drink, sport drink, coffee with milk, isotonic water and mineral water, and in these beverages several microorganism types were used: nine bacteria including three toxin producers, three yeasts, and five moulds. Following inoculation, the bottles were incubated at 35°C for 48 h for bacteria, 25°C for 48 h for yeasts, and 25°C for 28 days for moulds. During the incubation period, the number of bacteria and yeasts and visible changes in mould-growth were determined over time. Our results indicated that combinations of the beverage types and microorganism species correlated with the degree of growth. Regarding factors that affect the growth and toxin-productivity of microorganisms in beverages, it is speculated that the pH, static/shaking culture, temperature, additives, or ingredients, such as carbon dioxide or organic matter (especially of plant origin), may be important for microorganism growth in beverages. Our results suggest that various types of unfinished beverages have microorganism growth and can include food borne pathogens and bacterial toxins. Therefore, our results indicate that in terms of food hygiene it is necessary to consume beverages immediately after opening

The effect of size and competition on tree growth rate in old-growth coniferous forests

Science.gov (United States)

Das, Adrian

2012-01-01

Tree growth and competition play central roles in forest dynamics. Yet models of competition often neglect important variation in species-specific responses. Furthermore, functions used to model changes in growth rate with size do not always allow for potential complexity. Using a large data set from old-growth forests in California, models were parameterized relating growth rate to tree size and competition for four common species. Several functions relating growth rate to size were tested. Competition models included parameters for tree size, competitor size, and competitor distance. Competitive strength was allowed to vary by species. The best ranked models (using Akaike’s information criterion) explained between 18% and 40% of the variance in growth rate, with each species showing a strong response to competition. Models indicated that relationships between competition and growth varied substantially among species. The results also suggested that the relationship between growth rate and tree size can be complex and that how we model it can affect not only our ability to detect that complexity but also whether we obtain misleading results. In this case, for three of four species, the best model captured an apparent and unexpected decline in potential growth rate for the smallest trees in the data set.

Real-time corrosion monitoring of steel influenced by microbial activity (SRB) under controlled seawater injection conditions

Energy Technology Data Exchange (ETDEWEB)

Kane, Russell D. [InterCorr International, Inc., 14503 Bammel N. Houston Road, Suite 300, Houston, TX 77019 (United States); Campbell, Scott [Commercial Microbiology Inc., 10400 Westoffice Drive Suite 107, Houston, TX 77042 (United States)

2004-07-01

An experimental study of microbiologically influenced corrosion (MIC) was conducted involving online, real-time monitoring of a bio-film loop under controlled conditions simulating oil field water handling and injection. Bio-film growth, MIC and biocide efficacy were monitored using an automated, multi-technique monitoring system including linear polarization resistance, electrochemical noise and harmonic distortion analysis. This data was correlated with conventional off-line methods to differentiate conditions of varying MIC activity in real-time to facilitate quick assessment and operator intervention. (authors)

Processes influencing migration of bioavailable organic compounds from polymers - investigated during biotic and abiotic testing under static and non-static conditions with varying S/V-ratios

DEFF Research Database (Denmark)

Corfitzen, Charlotte B.; Arvin, Erik; Albrechtsen, Hans-Jørgen

. The bioavailable migration from the polymer surface was influence by diffusion over the solid-liquid boundary layer under sterile conditions, which resulted in an inversely proportionally relationship between bioavailable migration expressed per unit surface area of material and the surface to volume ratio (S/V-ratio...... the effect of the boundary layer, since bioavailable migration was continuously consumed by the bacteria. Thus the driving force for the diffusion process was maintained at a maximum, thereby enhancing the bioavailable migration from the material surfaces. Thus neither non-static conditions nor varying S/V-ratios...

Optimization and effects of different culture conditions on growth of Halomicronema hongdechloris – a filamentous cyanobacterium containing chlorophyll f

Directory of Open Access Journals (Sweden)

Yaqiong eLi

2014-02-01

Full Text Available A chlorophyll f containing cyanobacterium, Halomicronema hongdechloris (H. hongdechloris was isolated from a stromatolite cyanobacterial community. However, the extremely slower growth rate of H. hongdechloris culture became a critical factor, hindering the research on this newly isolated cyanobacterium and the investigation of chlorophyll f-photosynthesis. Therefore, optimizing H. hongdechloris culture conditions has become an essential requirement for future research. This work investigated the effects of various culture conditions, essential nutrients and light environments to determine the optimal growth conditions for H. hongdechloris and the biosynthetic rate of chlorophyll f. Based on the total chlorophyll concentration, an optimal growth rate of 0.22 ± 0.02 day-1 (doubling time: 3.1 ± 0.3 days was observed when cells were grown under continuous illumination with far-red light with an intensity of 20 µE at 32°C in modified K+ES seawater (pH 8.0 with additional supplements of 11.75 mM NaNO3 and 0.15 mM K2HPO4. High performance liquid chromatography on H. hongdechloris pigments confirmed that chlorophyll a is the major chlorophyll and chlorophyll f constitutes approximately 10% of the total chlorophyll from cells grown under far-red light. Fluorescence confocal image analysis demonstrated changes of photosynthetic membranes and the distribution of photopigments in response to different light conditions. The total photosynthetic oxygen evolution yield per cell showed no changes under different light conditions, which confirms the involvement of chlorophyll f in oxygenic photosynthesis. The implications of the presence of chlorophyll f in H. hongdechloris and its relationship to light environment are discussed.

Differential growth response of Ulva lactuca to ammonium and nitrate assimilation

DEFF Research Database (Denmark)

Ale, Marcel Tutor; Mikkelsen, Jørn Dalgaard; Meyer, Anne S

2011-01-01

and fluctuating levels of nitrogen sources. Our understanding of the influences of this varying condition on the uptake and growth responses of U. lactuca is limited. In this present work, we examined the growth response of U. lactuca exposed to different sources of nitrogen (NH4+; NO3−; and the combination NH4NO...... as the nitrogen source. The NH4Cl and NaNO3 rich media (50 μM of N) accelerated U. lactuca growth to a maximum specific growth rate of 16.4 ± 0.18% day−1 and 9.4 ± 0.72% day−1, respectively. The highest biomass production rate obtained was 22.5 ± 0.24 mg DW m−2·day−1. The presence of ammonium apparently...... discriminated the nitrate uptake by U. lactuca when exposed to NH4NO3. Apart from showing the significant differential growth response of U. lactuca to different nitrogen sources, the work exhibits the applicability of a photo-scanning approach for acquiring precise quantitative growth data for U. lactuca...

Decolorisation of Congo Red by Aeromonas hydrophila Under Microaerophilic Conditions

International Nuclear Information System (INIS)

El Gizawy, S.; Refae, R.A.; Abd El Kareem, H.; Gomaa, O.M.; Hamed, H.

2009-01-01

Among 22 local bacterial isolates, Aeromonas hydrophila isolated from Bolti fish showed a remarkable ability to decolorize congo red under microaerophilic conditions (98.8% in 48 hrs) without prior adaptation. The bacterium had the ability to grow and decolorized high concentrations of congo red which varied from 50 to 1000 mg/l , the decolorisation was irrelevant to bacterial growth. The strain was capable of decolorizing congo red under a wide range of temperatures (20-40 degree C), ph (3-8), NaCl (0-200 mg/l) and also had the ability to decolorized mono, di and poly azo dyes. This bacterium is notable in its ability to decolorized the diazo congo red under extreme conditions of temperature, ph, salinity and high dye concentrations which makes it suitable for decolorisation under extreme industrial conditions

Effect of Glomus mosseae and plant growth promoting rhizomicroorganisms (PGPR's on growth, nutrients and content of secondary metabolites in Begonia malabarica Lam.

Directory of Open Access Journals (Sweden)

Thangavel Selvaraj

2008-10-01

Full Text Available Begonia malabarica Lam. (Begoniaceae is one of the important medicinal plants whose main secondary metabolites are luteolin, quercetin and β-sitosterol. The leaves are used for the treatment of respiratory tract infections, diarrhoea, blood cancer and skin diseases. A study was undertaken to determine the effect of arbuscular mycorrhizal (AM fungus, Glomus mosseae, and some plant growth promoting rhizomicro-organisms (PGPR's on the growth, biomass, nutrients, and content of secondary metabolites of B. malabarica plant under green house conditions. Various plant growth parameters (total plant biomass, mycorrhizal parameter, shoot and root phosphorus, mineral content (potassium, iron, zinc, and copper, and secondary metabolites (total phenols, ortho-dihydroxy phenols, tannins, flavonoids, and alkaloids were determined and found to vary with different treatments. Among all the treatments, plants inoculated with 'microbial consortium' consisting of Glomus mosseae + Bacillus coagulans + Trichoderma viride performed better than with other treatments or uninoculated control plants. The results of this experiment clearly indicated that inoculation of B. malabarica with G. mosseae along with PGPR's enhanced its growth, biomass yield, nutrients and secondary metabolites.

Bounds and asymptotics for orthogonal polynomials for varying weights

CERN Document Server

Levin, Eli

2018-01-01

This book establishes bounds and asymptotics under almost minimal conditions on the varying weights, and applies them to universality limits and entropy integrals.  Orthogonal polynomials associated with varying weights play a key role in analyzing random matrices and other topics.  This book will be of use to a wide community of mathematicians, physicists, and statisticians dealing with techniques of potential theory, orthogonal polynomials, approximation theory, as well as random matrices. .

Varying hydric conditions during incubation influence egg water exchange and hatchling phenotype in the red-eared slider turtle.

Science.gov (United States)

Delmas, Virginie; Bonnet, Xavier; Girondot, Marc; Prévot-Julliard, Anne-Caroline

2008-01-01

Environmental conditions within the nest, notably temperature and moisture of substrate, exert a powerful influence during embryogenesis in oviparous reptiles. The influence of fluctuating nest temperatures has been experimentally examined in different reptile species; however, similar experiments using moisture as the key variable are lacking. In this article, we examine the effect of various substrate moisture regimes during incubation on different traits (egg mass, incubation length, and hatchling mass) in a chelonian species with flexible-shelled eggs, the red-eared slider turtle (Trachemys scripta elegans). Our results show that the rate of water uptake by the eggs was higher in wet than in dry substrate and varied across development. More important, during the first third of development, the egg mass changes were relatively independent of the soil moisture level; they became very sensitive to moisture levels during the other two-thirds. Moreover, hydric conditions exerted a strong influence on the eggs' long-term sensitivity to the moisture of the substrate. Even short-term episodes of high or low levels of moisture modified permanently their water sensitivity, notably through modification of eggshell shape and volume, and in turn entailed significant effects on hatchling mass (and hence offspring quality). Such complex influences of fluctuating moisture levels at various incubation stages on hatchling phenotype better reflect the natural situation, compared to experiments based on stable, albeit different, moisture levels.

Impact of growth and annealing conditions on the parameters of Ge/Si(001) relaxed layers grown by molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Yurasov, D. V., E-mail: Inquisitor@ipm.sci-nnov.ru [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Bobrov, A. I. [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Daniltsev, V. M.; Novikov, A. V. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Pavlov, D. A. [Lobachevsky State University of Nizhny Novgorod (Russian Federation); Skorokhodov, E. V.; Shaleev, M. V.; Yunin, P. A. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

2015-11-15

Influence of the Ge layer thickness and annealing conditions on the parameters of relaxed Ge/Si(001) layers grown by molecular beam epitaxy via two-stage growth is investigated. The dependences of the threading dislocation density and surface roughness on the Ge layer thickness, annealing temperature and time, and the presence of a hydrogen atmosphere are obtained. As a result of optimization of the growth and annealing conditions, relaxed Ge/Si(001) layers which are thinner than 1 μm with a low threading dislocation density on the order of 10{sup 7} cm{sup –2} and a root mean square roughness of less than 1 nm are obtained.

Effect of cultural conditions on the seed-to-seed growth of Arabidopsis and Cardamine - A study of growth rates and reproductive development as affected by test tube seals

Science.gov (United States)

Hoshizaki, T.

1982-01-01

The effects of test tube seals on the growth, flowering, and seed pod formation of Arabidopsis thaliana (L.) Heynh., mouse ear cress, and Cardamine oligosperma Nutt, bitter cress, are studied in order to assess the conditions used in weightlessness experiments. Among other results, it is found that the growth (height) and flowering (date of bud appearance) were suppressed in mouse ear cress in tubes sealed with Saran. Seed pod formation which occurred by day 45 in open-to-air controls, was still lacking in the sealed plants even up to day 124. The growth and flowering of bitter cress were also suppressed by the Saran seal, although up to day 55 the Saran-sealed plants were taller. It is suggested that atmospheric composition was the cause of the suppression of growth, flowering, and seed pod development in these plants, since the mouse ear cress renewed their growth and then set seed pods after the Saran seal was ruptured.

Resolving the Complex Genetic Basis of Phenotypic Variation and Variability of Cellular Growth.

Science.gov (United States)

Ziv, Naomi; Shuster, Bentley M; Siegal, Mark L; Gresham, David

2017-07-01

In all organisms, the majority of traits vary continuously between individuals. Explaining the genetic basis of quantitative trait variation requires comprehensively accounting for genetic and nongenetic factors as well as their interactions. The growth of microbial cells can be characterized by a lag duration, an exponential growth phase, and a stationary phase. Parameters that characterize these growth phases can vary among genotypes (phenotypic variation), environmental conditions (phenotypic plasticity), and among isogenic cells in a given environment (phenotypic variability). We used a high-throughput microscopy assay to map genetic loci determining variation in lag duration and exponential growth rate in growth rate-limiting and nonlimiting glucose concentrations, using segregants from a cross of two natural isolates of the budding yeast, Saccharomyces cerevisiae We find that some quantitative trait loci (QTL) are common between traits and environments whereas some are unique, exhibiting gene-by-environment interactions. Furthermore, whereas variation in the central tendency of growth rate or lag duration is explained by many additive loci, differences in phenotypic variability are primarily the result of genetic interactions. We used bulk segregant mapping to increase QTL resolution by performing whole-genome sequencing of complex mixtures of an advanced intercross mapping population grown in selective conditions using glucose-limited chemostats. We find that sequence variation in the high-affinity glucose transporter HXT7 contributes to variation in growth rate and lag duration. Allele replacements of the entire locus, as well as of a single polymorphic amino acid, reveal that the effect of variation in HXT7 depends on genetic, and allelic, background. Amplifications of HXT7 are frequently selected in experimental evolution in glucose-limited environments, but we find that HXT7 amplifications result in antagonistic pleiotropy that is absent in naturally

Sclerotial biomass and carotenoid yield of Penicillium sp. PT95 under oxidative growth conditions and in the presence of antioxidant ascorbic acid.

Science.gov (United States)

Li, X L; Cui, X H; Han, J R

2006-09-01

To determine the effect of oxidative stress and exogenous ascorbic acid on sclerotial biomass and carotenoid yield of Penicillium sp. PT95. In this experiment, high oxidative stress was applied by the inclusion of FeSO(4) in the growth medium and exposure to light. Low oxidative stress was applied by omitting iron from the growth medium and by incubation in the dark. Supplementation of exogenous ascorbic acid (as antioxidant) to the basal medium caused a concentration-dependent delay of sclerotial differentiation (up to 48 h), decrease of sclerotial biomass (up to 40%) and reduction of carotenoid yield (up to 91%). On the contrary, the exogenous ascorbic acid also caused a concentration-dependent decrease of lipid peroxidation in colonies of this fungus. Under high oxidative stress growth condition, the sclerotial biomass and carotenoid yield of PT95 strain in each plate culture reached 305 mg and 32.94 microg, which were 1.23 and 3.71 times higher, respectively, than those at low oxidative stress growth condition. These data prompted us to consider that in order to attain higher sclerotial biomass and pigment yield, the strain PT95 should be grown under high oxidative stress and in the absence of antioxidants. These results suggest that strain PT95 may be used for solid-state fermentation of carotenoid production under high oxidative stress growth conditions.

In-Pile Tests for IASCC Growth Behavior of Irradiated 316L Stainless Steel under Simulated BWR Condition in JMTR

Science.gov (United States)

Chimi, Yasuhiro; Kasahara, Shigeki; Ise, Hideo; Kawaguchi, Yoshihiko; Nakano, Junichi; Nishiyama, Yutaka

The Japan Atomic Energy Agency (JAEA) has an in-pile irradiation test plan to evaluate in-situ effects of neutron/γ-ray irradiation on stress corrosion crack (SCC) growth of irradiated stainless steels using the Japan Materials Testing Reactor (JMTR). SCC growth rate and its dependence on electrochemical corrosion potential (ECP) are different between in-pile test and post irradiation examination (PIE). These differences are not fully understood because of a lack of in-pile data. This paper presents a systematic review on SCC growth data of irradiated stainless steels, an in-pile test plan for crack growth of irradiated SUS316L stainless steel under simulated BWR conditions in the JMTR, and the development of the in-pile test techniques.

Housing Cycles in Switzerland - A Time-Varying Approach

OpenAIRE

Drechsel, Dirk

2015-01-01

In light of the strong increase of house prices in Switzerland, we analyze the effects of mortgage rate shocks, changes in the interplay between housing demand and supply and GDP growth on house prices for the time period 1981- 2014. We employ Bayesian time-varying coefficients vector autoregressions to allow different monetary and immigration regimes over time. A number of structural changes, such as regulatory changes in the aftermath of the 1990s real estate crisis, the introduction of fre...

Modeling the Growth of Epiphytic Bacteria on Kale Treated by Thermosonication Combined with Slightly Acidic Electrolyzed Water and Stored under Dynamic Temperature Conditions.

Science.gov (United States)

Mansur, Ahmad Rois; Oh, Deog-Hwan

2016-08-01

The growth of epiphytic bacteria (aerobic mesophilic bacteria or Pseudomonas spp.) on kale was modeled isothermally and validated under dynamic storage temperatures. Each bacterial count on kale stored at isothermal conditions (4 to 25 °C) was recorded. The results show that maximum growth rate (μmax ) of both epiphytic bacteria increased and lag time (λ) decreased with increasing temperature (P 0.97), whereas lower R(2) > 0.86 and R(2) > 0.87 was observed for the λ and Nmax , respectively. The overall predictions of both epiphytic bacterial growths under nonisothermal conditions with temperature abuse of 15 °C agreed with the observed data, whereas those with temperature abuse of 25 °C were greatly overestimated. The appropriate parameter q0 (physiological state of cells), therefore, was adjusted by a trial and error to fit the model. This study demonstrates that the developed model was able to predict accurately epiphytic bacterial growth on kale stored under nonisothermal conditions particularly those with low temperature abuse of 15 °C. © 2016 Institute of Food Technologists®

Microbial community diversity and composition varies with habitat characteristics and biofilm function in macrophyte-rich streams

DEFF Research Database (Denmark)

Levi, Peter S.; Starnawski, Piotr; Poulsen, Britta

2017-01-01

Biofilms in streams play an integral role in ecosystem processes and function yet few studies have investigated the broad diversity of these complex prokaryotic and eukaryotic microbial communities. Physical habitat characteristics can affect the composition and abundance of microorganisms...... in these biofilms by creating microhabitats. Here we describe the prokaryotic and eukaryotic microbial diversity of biofilms in sand and macrophyte habitats (i.e. epipsammon and epiphyton, respectively) in five macrophyte-rich streams in Jutland, Denmark. The macrophyte species varied in growth morphology, C......:N stoichiometry, and preferred stream habitat, providing a range in environmental conditions for the epiphyton. Among all habitats and streams, the prokaryotic communities were dominated by common phyla, including Alphaproteobacteria, Bacteriodetes, and Gammaproteobacteria, while the eukaryotic communities were...

Growth and industrial policy during transition

Directory of Open Access Journals (Sweden)

Cerovic Bozidar

2014-01-01

Full Text Available After twenty-five years of economic transition economic performance varies considerably in transition countries, while in most cases current outcomes show that the desired effects have not been achieved. In this paper we elaborate on why industrial policy has been a key missing element in the transition and has greatly contributed to the unexpectedly small and slow pace of economic recovery. After discussing the achieved level of economic development we undertake an empirical analysis in order to define the role of several important factors of growth, as seen at the beginning of transition (reform progress, macroeconomic stabilisation, initial conditions and those that attracted particular attention during the global crisis (industrial/manufacturing output, exports. The analysis shows that the growth model in transition economies has altered both over time and in relation to the progress of transition reforms. The most important change concerns the share of industrial output in GDP, which is found to be one of the most important factors of growth after the initial phase of reform. These results suggest that transition economies should implement industrial policy measures as an integral part of their reform strategy instead of just speeding up reforms as the key (if not the only element of government policy. Based on these results, we explore what would be a viable and proper industrial policy in transition countries, particularly what should be done in current conditions after the damaging effects of the recurrent global recession, and make some policy suggestions.

A reciprocal Wald theorem for varying gravitational function

International Nuclear Information System (INIS)

Fay, Stephane

2004-01-01

We study when a cosmological constant is a natural issue if it is mimicked by the potential of a massive Hyperextended Scalar Tensor theory with a perfect fluid for Bianchi type I and V models. We then deduce a reciprocal Wald theorem giving the conditions such that the potential tends to a non vanishing constant when the gravitational function varies. We also get the conditions allowing the potential to vanish or diverge. (orig.)

Development of Atlantic salmon (Salmo salar) eggs and alevins under varied temperature regimes

Energy Technology Data Exchange (ETDEWEB)

Peterson, R H; Spinney, H C.E.; Sreedharan, A

1977-01-01

Atlantic salmon (Salmo salar) eggs and alevins were raised under conditions where the temperature was systematically varied either at fertilization, at the eyed egg stage, or at hatching. Mortality was more than 20% in eggs started immediately after fertilization at constant incubation temperatures <4/sup 0/C as compared with 5% or less at temperatures >4/sup 0/C. Alevins that eyed at 8/sup 0/C and higher were progressively smaller the higher the temperature. The optimum temperature from fertilization to eye pigmentation was near 6/sup 0/C. Eyed eggs reared at lower temperatures until hatching were larger than those hatched at higher temperatures. This size differential was maintained until the yolk was completely absorbed at all posthatching temperatures investigated. Sudden decreases in temperature at the eyed egg and hatching stages induced severe edema of the alevin yolk sac, resulting in slower growth and increased mortality.

Impact of Varying Wave Conditions on the Mobility of Arsenic in a Nearshore Aquifer on the Great Lakes

Science.gov (United States)

Rakhimbekova, S.; O'Carroll, D. M.; Robinson, C. E.

2017-12-01

Groundwater-coastal water interactions play an important role in controlling the behavior of inorganic chemicals in nearshore aquifers and the subsequent flux of these chemicals to receiving coastal waters. Previous studies have shown that dynamic groundwater flows and water exchange across the sediment-water interface can set up strong geochemical gradients and an important reaction zone in a nearshore aquifer that affect the fate of reactive chemicals. There is limited understanding of the impact of transient coastal forcing such as wave conditions on groundwater dynamics and geochemistry in a nearshore aquifer. The goal of this study was to assess the impact of intensified wave conditions on the behavior of arsenic in a nearshore aquifer and to determine the hydrological and geochemical factors controlling its fate and ultimate delivery to receiving coastal waters. Field investigations were conducted over the period of intensified wave conditions on a freshwater beach on Lake Erie, Canada. High spatial resolution aqueous and sediment sampling was conducted to characterize the subsurface distribution of inorganic species in the nearshore aquifer. Numerical groundwater flow and transport simulations were conducted to evaluate wave-induced perturbations in the flow dynamics including characterizing changes in the groundwater flow recirculations in the nearshore aquifer. The combination of field data and numerical simulations reveal that varying wave conditions alter groundwater flows and set up geochemical transition zones within the aquifer resulting in the release and sequestration of arsenic. Interactions between oxic surface water, mildly reducing shallow groundwater, and reducing sulfur- and iron-rich deep groundwater promote dynamic iron, sulfur and manganese cycling which control the mobility of arsenic in the aquifer. The findings of this study have potential implications for the fate and transport of other reactive chemicals (e.g. phosphorus, mercury) in

Influence of the growth conditions on the optical and structural properties of self-assembled InAs/GaAs quantum dots for low As/In ratio

Energy Technology Data Exchange (ETDEWEB)

Ozdemir, Samet; Suyolcu, Y. Eren [Advanced Technologies Research Unit: Nanotechnology, Graduate School of Sciences, Anadolu University, Yunusemre Campus, 26470 Eskisehir (Turkey); Turan, Servet [Department of Materials Science and Engineering, Anadolu University, Iki Eylul Campus, 26555 Eskisehir (Turkey); Aslan, Bulent, E-mail: bulentaslan@anadolu.edu.tr [Department of Physics, Anadolu University, Yunusemre Campus, 26470 Eskisehir (Turkey)

2017-01-15

Highlights: • Effects of systematically changed growth conditions on InAs/GaAs QDs were studied. • Growths were optimized for low As/In flux ratio to obtain well-resolved PL spectra. • XRD rocking curve signal fitting was used to analyze the samples. • XRD analysis reflects the overall tendency of the QD density and WL behavior. - Abstract: We report on the growth and characterization of self-assembled InAs/GaAs quantum dots (QDs). The influence of the systematically changed growth conditions on the opto-electronic and structural properties of the QDs were investigated. Combination of the amount of the deposited InAs, growth temperature and growth rate were optimized for low As/In flux ratio to obtain well-resolved ground and excited states in the low temperature photoluminescence (PL) spectra. SEM and TEM techniques were also used for the characterization of QDs. The results were evaluated simply through the conservation of mass approximation and the x-ray diffraction measurements with fitted curves. The extracted InAs and wetting layer thicknesses were brought out that the XRD analysis reflects the overall tendency of the QD density change and WL behaviors in response to the changes in growth conditions.

The influence of prefire tree growth and crown condition on postfire mortality of sugar pine following prescribed fire in Sequoia National Park

Science.gov (United States)

Nesmith, Jonathan C. B.; Das, Adrian J.; O'Hara, Kevin L.; van Mantgem, Phillip J.

2015-01-01

Tree mortality is a vital component of forest management in the context of prescribed fires; however, few studies have examined the effect of prefire tree health on postfire mortality. This is especially relevant for sugar pine (Pinus lambertiana Douglas), a species experiencing population declines due to a suite of anthropogenic factors. Using data from an old-growth mixed-conifer forest in Sequoia National Park, we evaluated the effects of fire, tree size, prefire radial growth, and crown condition on postfire mortality. Models based only on tree size and measures of fire damage were compared with models that included tree size, fire damage, and prefire tree health (e.g., measures of prefire tree radial growth or crown condition). Immediately following the fire, the inclusion of different metrics of prefire tree health produced variable improvements over the models that included only tree size and measures of fire damage, as models that included measures of crown condition performed better than fire-only models, but models that included measures of prefire radial growth did not perform better. However, 5 years following the fire, sugar pine mortality was best predicted by models that included measures of both fire damage and prefire tree health, specifically, diameter at breast height (DBH, 1.37 m), crown scorch, 30-year mean growth, and the number of sharp declines in growth over a 30-year period. This suggests that factors that influence prefire tree health (e.g., drought, competition, pathogens, etc.) may partially determine postfire mortality, especially when accounting for delayed mortality following fire.

Colonization with Arbuscular Mycorrhizal Fungi Promotes the Growth of Morus alba L. Seedlings under Greenhouse Conditions

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Nan Lu

2015-03-01

Full Text Available Morus alba L. is an important tree species planted widely in China because of its economic value. In this report, we investigated the influence of two arbuscular mycorrhizal fungal (AMF species, Glomus mosseae and Glomus intraradices, alone and together, on the growth of M. alba L. seedlings under greenhouse conditions. The growth parameters and physiological performance of M. alba L. seedlings were evaluated 90 days after colonization with the fungi. The growth and physiological performance of M. alba L. seedlings were significantly affected by the AMF species. The mycorrhizal seedlings were taller, had longer roots, more leaves and a greater biomass than the non-mycorrhizae-treated seedlings. In addition, the AMF species-inoculated seedlings had increased root activity and a higher chlorophyll content compared to non-inoculated seedlings. Furthermore, AMF species colonization increased the phosphorus and nitrogen contents of the seedlings. In addition, simultaneous root colonization by the two AMF species did not improve the growth of M. alba L. seedlings compared with inoculation with either species alone. Based on these results, these AMF species may be applicable to mulberry seedling cultivation.

Growth strategies of tropical tree species: disentangling light and size effects.

Directory of Open Access Journals (Sweden)

Nadja Rüger

Full Text Available An understanding of the drivers of tree growth at the species level is required to predict likely changes of carbon stocks and biodiversity when environmental conditions change. Especially in species-rich tropical forests, it is largely unknown how species differ in their response of growth to resource availability and individual size. We use a hierarchical bayesian approach to quantify the impact of light availability and tree diameter on growth of 274 woody species in a 50-ha long-term forest census plot in Barro Colorado Island, Panama. Light reaching each individual tree was estimated from yearly vertical censuses of canopy density. The hierarchical bayesian approach allowed accounting for different sources of error, such as negative growth observations, and including rare species correctly weighted by their abundance. All species grew faster at higher light. Exponents of a power function relating growth to light were mostly between 0 and 1. This indicates that nearly all species exhibit a decelerating increase of growth with light. In contrast, estimated growth rates at standardized conditions (5 cm dbh, 5% light varied over a 9-fold range and reflect strong growth-strategy differentiation between the species. As a consequence, growth rankings of the species at low (2% and high light (20% were highly correlated. Rare species tended to grow faster and showed a greater sensitivity to light than abundant species. Overall, tree size was less important for growth than light and about half the species were predicted to grow faster in diameter when bigger or smaller, respectively. Together light availability and tree diameter only explained on average 12% of the variation in growth rates. Thus, other factors such as soil characteristics, herbivory, or pathogens may contribute considerably to shaping tree growth in the tropics.

Marked stimulation of growth and motility of human keratinocytes by hepatocyte growth factor

International Nuclear Information System (INIS)

Matsumoto, K.; Hashimoto, K.; Yoshikawa, K.; Nakamura, T.

1991-01-01

Effect of hepatocyte growth factor (HGF) on normal human epidermal keratinocytes cultured under conditions of low Ca2+ (0.1 mM, growth-promoting condition) and physiological Ca2+ (1.8 mM, differentiation-promoting condition) was investigated. In low Ca2+, HGF markedly enhanced the migration of keratinocytes while it suppressed cell growth and DNA synthesis in a dose-dependent manner. In contrast, HGF enhanced the migration, cell growth, and DNA synthesis of keratinocytes cultured under conditions of physiological Ca2+. The maximal stimulation of DNA synthesis (2.4-fold stimulation) in physiological Ca2+ was seen at 2.5-5 ng/ml HGF and the stimulatory effect of HGF was suppressed by transforming growth factor-beta 1. Analysis of the HGF receptor using 125I-HGF as a ligand showed that human keratinocytes expressed a single class of specific, saturable receptor for HGF in both low and physiological Ca2+ conditions, exhibiting a Kd = 17.3 pM and approximately 690 binding sites/cell under physiological Ca2+. Thus, HGF is a potent factor which enhances growth and migration of normal human keratinocytes under conditions of physiological Ca2+. HGF may play an important role in epidermal tissue repair as it enhances both the migration and growth of keratinocytes

Effect of deposition conditions on the growth rate and electrical properties of ZnO thin films grown by MOCVD

Energy Technology Data Exchange (ETDEWEB)

Roro, K.T.; Botha, J.R.; Leitch, A.W.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)

2008-07-01

ZnO thin films have been grown on glass substrates by MOCVD. The effect of deposition conditions such as VI/II molar ratio, DEZn flow rate and total reactor pressure on the growth rate and electrical properties of the films was studied. It is found that the growth rate decreases with an increase in the VI/II molar ratio. This behaviour is ascribed to the competitive adsorption of reactant species on the growth surface. The growth rate increases with an increase in DEZn flow rate, as expected. It is shown that the carrier concentration is independent of the DEZn flow rate. An increase in the total reactor pressure yields a decrease in growth rate. This phenomenon is attributed to the depletion of the gas phase due to parasitic prereactions between zinc and oxygen species at high pressure. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Anatomical and Physiological Responses of Citrus Trees to Varying Boron Availability Are Dependent on Rootstock.

Science.gov (United States)

Mesquita, Geisa L; Zambrosi, Fernando C B; Tanaka, Francisco A O; Boaretto, Rodrigo M; Quaggio, José A; Ribeiro, Rafael V; Mattos, Dirceu

2016-01-01

In Citrus, water, nutrient transport and thereby fruit production, are influenced among other factors, by the interaction between rootstock and boron (B) nutrition. This study aimed to investigate how B affects the anatomical structure of roots and leaves as well as leaf gas exchange in sweet orange trees grafted on two contrasting rootstocks in response to B supply. Plants grafted on Swingle citrumelo or Sunki mandarin were grown in a nutrient solution of varying B concentration (deficient, adequate, and excessive). Those grafted on Swingle were more tolerant to both B deficiency and toxicity than those on Sunki, as revealed by higher shoot and root growth. In addition, plants grafted on Sunki exhibited more severe anatomical and physiological damages under B deficiency, showing thickening of xylem cell walls and impairments in whole-plant leaf-specific hydraulic conductance and leaf CO2 assimilation. Our data revealed that trees grafted on Swingle sustain better growth under low B availablitlity in the root medium and still respond positively to increased B levels by combining higher B absorption and root growth as well as better organization of xylem vessels. Taken together, those traits improved water and B transport to the plant canopy. Under B toxicity, Swingle rootstock would also favor plant growth by reducing anatomical and ultrastructural damage to leaf tissue and improving water transport compared with plants grafted on Sunki. From a practical point of view, our results highlight that B management in citrus orchards shall take into account rootstock varieties, of which the Swingle rootstock was characterized by its performance on regulating anatomical and ultrastructural damages, improving water transport and limiting negative impacts of B stress conditions on plant growth.

TEM studies of the crystal growth of indanthrone pigments

International Nuclear Information System (INIS)

McHendry, P.

1998-01-01

The aim of this work was to study the crystal growth of indanthrone during the pigmentation process. The colouring properties of a pigment are dependant on the chemical and crystallographic structure of the pigment. However, other factors are known to affect these properties including particle size, particle size distribution and level of dispersion in the chosen application medium. The parameters which affect the growth of the pigment particles were investigated with the emphasis placed on the mechanism by which growth took place. The final form of the crystals after growth was also investigated in some detail. Various electron microscopy techniques were employed in the investigations in this thesis. High and low magnification imaging and diffraction were studied on the CTEM (conventional transmission electron microscope) whilst PEELS (parallel electron energy loss spectroscopy) and DPC (differential phase contrast) studies took place on the VG HB5 STEM (scanning transmission electron microscope). In addition to these studies, x-ray diffraction and surface area analysis techniques were employed. The low magnification CTEM work gave good information on the size, shape and size distribution of the pigment particles and enabled detailed analysis of the level of growth attained under varied reaction conditions. (author)

Characteristics of light and heat conditions of a chamber with prism light guides and electrodeless discharge lamps and its effect on growth of tomato and cucumber seedlings

International Nuclear Information System (INIS)

Higashide, T.; Shimaji, H.; Hamamoto, H.; Shimazu, T.; Takaichi, M.

2004-01-01

Summary Light and heat conditions were measured in a growth chamber with prism light guides and electrolodeless discharge lamps (LP chamber) , a growth chamber with metal halide lamps (MH chamber) and a glasshouse. In the LP chamber, photosynthetic photon flux (PPF) was larger and heat radiation was smaller than in the others. Growth of tomato seedlings increased in high PPF condition. However, the growth with high PPF in the MH chamber was restricted. Leaf temperature with high PPF in the MH chamber was higher than that in the LP chamber. We thought that excessive heat had restricted the growth with high PPF in the MH chamber. There were no differences in nutrient or water absorption, except with conditions of the largest heat radiation and the lowest PPF. Cucumber seedlings were grown with high PPF in the LP chamber. The growth at high temperatures was smaller than that at the optimum temperature. However the leaf number at high temperatures was higher than that at the optimum temperature

On the formation of sulphuric acid – amine clusters in varying atmospheric conditions and its influence on atmospheric new particle formation

Directory of Open Access Journals (Sweden)

I. K. Ortega

2012-10-01

Full Text Available Sulphuric acid is a key component in atmospheric new particle formation. However, sulphuric acid alone does not form stable enough clusters to initiate particle formation in atmospheric conditions. Strong bases, such as amines, have been suggested to stabilize sulphuric acid clusters and thus participate in particle formation. We modelled the formation rate of clusters with two sulphuric acid and two amine molecules (JA2B2 at varying atmospherically relevant conditions with respect to concentrations of sulphuric acid ([H2SO4], dimethylamine ([DMA] and trimethylamine ([TMA], temperature and relative humidity (RH. We also tested how the model results change if we assume that the clusters with two sulphuric acid and two amine molecules would act as seeds for heterogeneous nucleation of organic vapours (other than amines with higher atmospheric concentrations than sulphuric acid. The modelled formation rates JA2B2 were functions of sulphuric acid concentration with close to quadratic dependence, which is in good agreement with atmospheric observations of the connection between the particle formation rate and sulphuric acid concentration. The coefficients KA2B2 connecting the cluster formation rate and sulphuric acid concentrations as JA2B2=KA2B2[H2SO4]2 turned out to depend also on amine concentrations, temperature and relative humidity. We compared the modelled coefficients KA2B2 with the corresponding coefficients calculated from the atmospheric observations (Kobs from environments with varying temperatures and levels of anthropogenic influence. By taking into account the modelled behaviour of JA2B2 as a function of [H2SO4], temperature and RH, the atmospheric particle formation rate was reproduced more closely than with the traditional semi-empirical formulae based on sulphuric acid concentration only. The formation rates of clusters with two sulphuric acid and two amine molecules with different amine compositions (DMA or TMA or one of both had

Volatility spillover and time-varying conditional correlation between DDGS, corn, and soybean meal markets

NARCIS (Netherlands)

Etienne, Xiaoli L.; Trujillo-Barrera, Andrés; Hoffman, Linwood A.

2017-01-01

We find distiller's dried grains with solubles (DDGS) prices to be positively correlated with both corn and soybean meal prices in the long run. However, neither corn nor soybean meal prices respond to deviations from this long-run relationship. We also identify strong time-varying dynamic

The Effectiveness of Experimental Diet with Varying Levels of Papain on The Growth Performance, Survival Rate and Feed Utilization of Keureling Fish (Tor tambra

Directory of Open Access Journals (Sweden)

Zainal Abidin Muchlisin

2016-09-01

Full Text Available The objective of present study was to determine the optimum level of papain in the diet of keureling fish (Tor tambra. The complete random design was utilized in this study. Six levels of papain dosage were tested in triplicates, i.e. 0 (control; 17.5 mg kg-1,  20.0 mg kg-1, 22.5 mg kg-1, 25.0 mg kg-1 and 27.5 mg kg-1 of feed. The experimental fish were fed the experimental diet two times a day at 8 AM and 5 PM at feeding level of 5% body weight for 90 days. The Anova test result showed that papain enzyme  gave a significant effect on the weight gain, daily growth rate, specific growth rate, survival rate, feed conversion ratio and feed efficiency (P<0.05. The Duncan multi-rage test result showed that the higher values for all measured parameters were obtained at the dosage of 27.5 mg kg-1. Therefore, it is concluded that the optimum dosage of papain enzyme for keureling fish was 27.5 mg kg-1 of feed.How to CiteMuchlisin, Z. A., Afrido, F., Murda, T., Fadli, N., Muhammadar, A. A., Jalil, Z., & Yulvizar, C. (2016. The Effectiveness of Experimental Diet with Varying Levels of Papain on The Growth Performance, Survival Rate and Feed Utilization of Keureling Fish (Tor tambra. Biosaintifika: Journal of Biology & Biology Education, 8(2, 172-177.

Asymmetric Vibration of Polar Orthotropic Annular Circular Plates of Quadratically Varying Thickness with Same Boundary Conditions

Directory of Open Access Journals (Sweden)

N. Bhardwaj

2008-01-01

Full Text Available In the present paper, asymmetric vibration of polar orthotropic annular circular plates of quadratically varying thickness resting on Winkler elastic foundation is studied by using boundary characteristic orthonormal polynomials in Rayleigh-Ritz method. Convergence of the results is tested and comparison is made with results already available in the existing literature. Numerical results for the first ten frequencies for various values of parameters describing width of annular plate, thickness profile, material orthotropy and foundation constant for all three possible combinations of clamped, simply supported and free edge conditions are shown and discussed. It is found that (a higher elastic property in circumferential direction leads to higher stiffness against lateral vibration; (b Lateral vibration characteristics of F-Fplates is more sensitive towards parametric changes in material orthotropy and foundation stiffness than C-C and S-Splates; (c Effect of quadratical thickness variation on fundamental frequency is more significant in cases of C-C and S-S plates than that of F-Fplates. Thickness profile which is convex relative to plate center-line tends to result in higher stiffness of annular plates against lateral vibration than the one which is concave and (d Fundamental mode of vibration of C-C and S-Splates is axisymmetrical while that of F-Fplates is asymmetrical.

[Effect of exogenous sucrose on growth and active ingredient content of licorice seedlings under salt stress conditions].

Science.gov (United States)

Liu, Fu-zhi; Yang, Jun

2015-11-01

Licorice seedlings were taken as experimental materials, an experiment was conducted to study the effects of exogenous sucrose on growth and active ingredient content of licorice seedlings under NaCl stress conditions. The results of this study showed that under salt stress conditions, after adding a certain concentration of exogenous sucrose, the licorice seedlings day of relative growth rate was increasing, and this stress can be a significant weakening effect, indicating that exogenous sucrose salt stress-relieving effect. The total flavonoids and phenylalanine ammonia lyase (PAL) activity were significantly increased, the exogenous sucrose can mitigated the seedling roots under salt stress, the licorice flavonoid content in the enhanced growth was largely due to the activity of PAL an increased, when the concentration of exogenous sucrose wae 10 mmol x L(-1), PAL activity reaching a maximum, when the concentration of exogenous sucrose was 15 mmol x L(-1), PAL activity turned into a downward trend, the results indicating that this mitigation has concentration effect. After applying different concentrations of exogenous sugar, the contents of liquiritin changes with the change of flavonoids content was similar. After applying different concentrations of exogenous sucrose, the content of licorice acid under salt stress was higher than the levels were not reached during salt stress, the impact of exogenous sucrose concentration gradient of licorice acid accumulation was not obvious.

Modelling Time-Varying Volatility in Financial Returns

DEFF Research Database (Denmark)

Amado, Cristina; Laakkonen, Helinä

2014-01-01

The “unusually uncertain” phase in the global financial markets has inspired many researchers to study the effects of ambiguity (or “Knightian uncertainty”) on the decisions made by investors and their implications for the capital markets. We contribute to this literature by using a modified...... version of the time-varying GARCH model of Amado and Teräsvirta (2013) to analyze whether the increasing uncertainty has caused excess volatility in the US and European government bond markets. In our model, volatility is multiplicatively decomposed into two time-varying conditional components: the first...... being captured by a stable GARCH(1,1) process and the second driven by the level of uncertainty in the financial market....

A method comparison of total and HMW adiponectin: HMW/total adiponectin ratio varies versus total adiponectin, independent of clinical condition.

Science.gov (United States)

van Andel, Merel; Drent, Madeleine L; van Herwaarden, Antonius E; Ackermans, Mariëtte T; Heijboer, Annemieke C

2017-02-01

Total and high-molecular-weight (HMW) adiponectin have been associated with endocrine and cardiovascular pathology. As no gold standard is available, the discussion about biological relevance of isoforms is complicated. In our study we perform a method comparison between two commercially available assays measuring HMW and total adiponectin, in various patient groups, thus contributing further to this discussion. We determined levels of HMW and total adiponectin using assays by Lumipulse® and Millipore® respectively, in 126 patients with different clinical characteristics (n=29 healthy volunteers, n=22 dialysis patients, n=25 elderly with body mass index (BMI) LUMIPULSE ∗0.5-0.9=total adiponectin MILLIPORE , albeit with significant deviation from linearity (p<0.001). Pearson's correlation was R=0.987 (p=0.000). No significant differences between patient groups were observed (p=0.190). The HMW/total adiponectin ratio varies with total adiponectin concentration independent of clinical conditions studied. Our results imply that total and HMW adiponectin have similar utility when assessing adiponectin levels in blood, as the ratio is independent of clinical condition. Copyright © 2016 Elsevier B.V. All rights reserved.

A laboratory-calibrated model of coho salmon growth with utility for ecological analyses

Science.gov (United States)

Manhard, Christopher V.; Som, Nicholas A.; Perry, Russell W.; Plumb, John M.

2018-01-01

We conducted a meta-analysis of laboratory- and hatchery-based growth data to estimate broadly applicable parameters of mass- and temperature-dependent growth of juvenile coho salmon (Oncorhynchus kisutch). Following studies of other salmonid species, we incorporated the Ratkowsky growth model into an allometric model and fit this model to growth observations from eight studies spanning ten different populations. To account for changes in growth patterns with food availability, we reparameterized the Ratkowsky model to scale several of its parameters relative to ration. The resulting model was robust across a wide range of ration allocations and experimental conditions, accounting for 99% of the variation in final body mass. We fit this model to growth data from coho salmon inhabiting tributaries and constructed ponds in the Klamath Basin by estimating habitat-specific indices of food availability. The model produced evidence that constructed ponds provided higher food availability than natural tributaries. Because of their simplicity (only mass and temperature are required as inputs) and robustness, ration-varying Ratkowsky models have utility as an ecological tool for capturing growth in freshwater fish populations.

Effect of growth conditions on production of rhamnose-containing cell wall and capsular polysaccharides by strains of Lactobacillus casei subsp. rhamnosus.

Science.gov (United States)

Wicken, A J; Ayres, A; Campbell, L K; Knox, K W

1983-01-01

Strains of Lactobacillus casei subsp. rhamnosus possessing two cell wall polysaccharides, a hexosamine-containing H-polysaccharide and a rhamnose-containing R-polysaccharide, were examined for the effect of growth conditions on the production of these two components. In strain NCTC 6375, R- and H-polysaccharides accounted for an estimated 44 and 20%, respectively, of the cell wall for organisms grown in batch culture with glucose as the carbohydrate source. Growth on fructose-containing media reduced the amount of R-polysaccharide by approximately 50% without affecting the amount of H-polysaccharide. Subculture of fructose-grown organisms in glucose restored the original proportions of the two polysaccharides. Galactose- and sucrose-grown cells behaved similarly to glucose-grown cells with respect to polysaccharide production, whereas growth in rhamnose or ribose showed values close to those for fructose-grown cells. Continuous culture of strain NCTC 6375 for more than 100 generations showed a gradual and irreversible reduction of the R-polysaccharide to less than 5% of the cell wall and an increase of the H-polysaccharide to 40% of the cell wall. Other type culture strains of L. casei subsp. rhamnosus, NCIB 7473 and ATCC 7469, behaved similarly in batch and continuous culture. In contrast, strains of L. casei subsp. rhamnosus isolated at the Institute of Dental Research showed phenotypic stability with respect to the relative proportions of R- and H-polysaccharides in both batch and continuous culture. Changes in polysaccharide composition of type culture strains were also mirrored in changes in the immunogenicity of the two components and resistance to the rate of enzymic lysis of whole organisms. For L. casei subsp. rhamnosus strain NCTC 10302 the R-polysaccharide is present entirely as capsular material. The amount of R-polysaccharide produced was also markedly dependent on the carbohydrate component of the medium in batch culture and both dilution rate and

Plasticity in variation of xylem and phloem cell characteristics of Norway spruce under different local conditions

Directory of Open Access Journals (Sweden)

Jozica eGricar

2015-09-01

Full Text Available There is limited information on intra-annual plasticity of secondary tissues of tree species growing under different environmental conditions. To increase the knowledge about the plasticity of secondary growth, which allows trees to adapt to specific local climatic regimes, we examined climate–radial growth relationships of Norway spruce (Picea abies (L. H. Karst. from three contrasting locations in the temperate climatic zone by analyzing tree-ring widths for the period 1932–2010, and cell characteristics in xylem and phloem increments formed in the years 2009–2011. Variation in the structure of xylem and phloem increments clearly shows that plasticity in seasonal dynamics of cambial cell production and cell differentiation exists on xylem and phloem sides. Anatomical characteristics of xylem and phloem cells are predominantly site-specific characteristics, because they varied among sites but were fairly uniform among years in trees from the same site. Xylem and phloem tissues formed in the first part of the growing season seemed to be more stable in structure, indicating their priority over latewood and late phloem for tree performance. Long-term climate and radial growth analyses revealed that growth was in general less dependent on precipitation than on temperature; however, growth sensitivity to local conditions differed among the sites. Only partial dependence of radial growth of spruce on climatic factors on the selected sites confirms its strategy to adapt the structure of wood and phloem increments to function optimally in local conditions.

Influence of annealing condition and multicycle AlGaAs/GaAs structures on the Al0.26Ga0.74As surface morphology

International Nuclear Information System (INIS)

Wei, Wenzhe; Wang, Yi; Guo, Xiang; Luo, Zijiang; Zhao, Zhen; Zhou, Haiyue; Ding, Zhao

2015-01-01

Highlights: • STM study on the change of AlGaAs surface morphology with varying annealing conditions. • Interesting phenomenon that the subsequent sample has more surface roughness than the previous samples do. A physical model was proposed to explain why the multi-runs growth can increase surface roughness. • The annealing conditions of AlGaAs/GaAs surface were proposed. - Abstract: The influence of annealing temperature, As 4 beam equivalent pressure and multi-runs growth on AlGaAs/GaAs structures was investigated. The real space ultrahigh vacuum scanning tunneling microscopy images showed that AlGaAs/GaAs surface morphology greatly depends on annealing conditions and initial state of surface. The reasons of the surface phenomenon are proposed, and a physical model was proposed to explain why the multi-runs growth structures can increase AlGaAs surface roughness. The reasonable preparation conditions for AlGaAs/GaAs structures were proposed

The relationship between global oil price shocks and China's output: A time-varying analysis

International Nuclear Information System (INIS)

Cross, Jamie; Nguyen, Bao H.

2017-01-01

We employ a class of time-varying Bayesian vector autoregressive (VAR) models on new standard dataset of China's GDP constructed by to examine the relationship between China's economic growth and global oil market fluctuations between 1992Q1 and 2015Q3. We find that: (1) the time varying parameter VAR with stochastic volatility provides a better fit as compared to it's constant counterparts; (2) the impacts of intertemporal global oil price shocks on China's output are often small and temporary in nature; (3) oil supply and specific oil demand shocks generally produce negative movements in China's GDP growth whilst oil demand shocks tend to have positive effects; (4) domestic output shocks have no significant impact on price or quantity movements within the global oil market. The results are generally robust to three commonly employed indicators of global economic activity: Kilian's global real economic activity index, the metal price index and the global industrial production index, and two alternative oil price metrics: the US refiners' acquisition cost for imported crude oil and the West Texas Intermediate price of crude oil. - Highlights: • A class of time-varying BVARs is used to examine the relationship between China's economic growth and global oil market fluctuations. • The impacts of intertemporal global oil price shocks on China's output are often small and temporary in nature. • Oil supply and specific oil demand shocks generally produce negative movements in China's GDP growth while oil demand shocks tend to have positive effects. • Domestic output shocks have no significant impact on price or quantity movements within the global oil market.

Conservadorismo condicional: estudo a partir de variáveis econômicas Conditional conservatism: a study based on economic variables

Directory of Open Access Journals (Sweden)

Rafael de Lacerda Moreira

2010-12-01

Full Text Available A Contabilidade, na perspectiva da abordagem da informação, volta-se à utilidade da informação. O Conservadorismo Condicional está ligado à tendência de a Contabilidade exigir um maior grau de verificação das boas notícias para reconhecê-las no resultado em relação ao grau de verificação das más notícias. Em face das preocupações referentes à qualidade da informação contábil, o objetivo deste artigo consiste em analisar o reflexo do Conservadorismo Condicional no resultado contábil a partir de variáveis econômicas. O estudo utiliza o Modelo Reverso de Lucros Associados a Retornos (BASU, 1997 e o modelo proposto por Kahn e Watts (2009, que analisam a relação entre as variáveis lucro contábil e retorno econômico, utilizando os valores dos retornos positivos e negativos como proxy de boas e más notícias, e outras variáveis largamente aceitas na avaliação do conservadorismo. Para tanto, foram estimados os modelos estatísticos para uma amostra de 96 empresas para o período de 2005 a 2007 partindo de informações anuais disponíveis no Economática® e dados reportados em notas explicativas. Com o objetivo de selecionar um evento econômico que pode impactar no reconhecimento assimétrico do resultado econômico, decidiu-se comparar os resultados entre empresas listadas nos níveis de governança da Bovespa com as demais empresas. Os resultados obtidos confirmam a hipótese de utilização de conservadorismo condicional na mensuração do resultado das companhias da amostra. A diferenciação positiva quanto ao grau de conservadorismo para as empresas que aderiram aos níveis de governança não são conclusivas, visto que os modelos apresentaram resultados dispersos. As variáveis econômicas criam vantagens quando as más notícias não podem ser tão claramente visíveis nas Demonstrações Contábeis, podendo diminuir os resultados futuros esperados.Accounting from an information perspective looks at the

Growth Conditions Regulate the Requirements for Caulobacter Chromosome Segregation

DEFF Research Database (Denmark)

Shebelut, Conrad W.; Jensen, Rasmus Bugge; Gitai, Zemer

2009-01-01

Growth environments are important metabolic and developmental regulators. Here we demonstrate a growth environment-dependent effect on Caulobacter chromosome segregation of a small-molecule inhibitor of the MreB bacterial actin cytoskeleton. Our results also implicate ParAB as important segregation...... determinants, suggesting that multiple distinct mechanisms can mediate Caulobacter chromosome segregation and that their relative contributions can be environmentally regulated....

Suppression of elongation and growth of tomato seedlings by auxin biosynthesis inhibitors and modeling of the growth and environmental response.

Science.gov (United States)

Higashide, Tadahisa; Narukawa, Megumi; Shimada, Yukihisa; Soeno, Kazuo

2014-04-02

To develop a growth inhibitor, the effects of auxin inhibitors were investigated. Application of 30 μM L-α-aminooxy-β-phenylpropionic acid (AOPP) or (S)-methyl 2-((1,3-dioxoisoindolin-2-yl)oxy)-3-phenylpropanoate (KOK1101), decreased the endogenous IAA levels in tomato seedlings at 8 days after sowing. Then, 10-1200 μM AOPP or KOK1101 were sprayed on the leaves and stem of 2-3 leaf stage tomato plants grown under a range of environmental conditions. We predicted plant growth and environmental response using a model based on the observed suppression of leaf enlargement. Spraying AOPP or KOK1101 decreased stem length and leaf area. Concentration-dependent inhibitions and dose response curves were observed. Although the effects of the inhibitors on dry weight varied according to the environmental conditions, the net assimilation rate was not influenced by the inhibitors. Accordingly, the observed decrease in dry weight caused by the inhibitors may result from decreased leaf area. Validation of the model based on observed data independent of the dataset showed good correlations between the observed and predicted values of dry weight and leaf area index.

Intercoalescence time distribution of incomplete gene genealogies in temporally varying populations, and applications in population genetic inference.

Science.gov (United States)

Chen, Hua

2013-03-01

Tracing back to a specific time T in the past, the genealogy of a sample of haplotypes may not have reached their common ancestor and may leave m lineages extant. For such an incomplete genealogy truncated at a specific time T in the past, the distribution and expectation of the intercoalescence times conditional on T are derived in an exact form in this paper for populations of deterministically time-varying sizes, specifically, for populations growing exponentially. The derived intercoalescence time distribution can be integrated to the coalescent-based joint allele frequency spectrum (JAFS) theory, and is useful for population genetic inference from large-scale genomic data, without relying on computationally intensive approaches, such as importance sampling and Markov Chain Monte Carlo (MCMC) methods. The inference of several important parameters relying on this derived conditional distribution is demonstrated: quantifying population growth rate and onset time, and estimating the number of ancestral lineages at a specific ancient time. Simulation studies confirm validity of the derivation and statistical efficiency of the methods using the derived intercoalescence time distribution. Two examples of real data are given to show the inference of the population growth rate of a European sample from the NIEHS Environmental Genome Project, and the number of ancient lineages of 31 mitochondrial genomes from Tibetan populations. © 2013 Blackwell Publishing Ltd/University College London.

Validity limits in J-resistance curve determination: A computational approach to ductile crack growth under large-scale yielding conditions. Volume 2

International Nuclear Information System (INIS)

Shih, C.F.; Xia, L.; Hutchinson, J.W.

1995-02-01

In this report, Volume 2, Mode I crack initiation and growth under plane strain conditions in tough metals are computed using an elastic/plastic continuum model which accounts for void growth and coalescence ahead of the crack tip. The material parameters include the stress-strain properties, along with the parameters characterizing the spacing and volume fraction of voids in material elements lying in the plane of the crack. For a given set of these parameters and a specific specimen, or component, subject to a specific loading, relationships among load, load-line displacement and crack advance can be computed with no restrictions on the extent of plastic deformation. Similarly, there is no limit on crack advance, except that it must take place on the symmetry plane ahead of the initial crack. Suitably defined measures of crack tip loading intensity, such as those based on the J-integral, can also be computed, thereby directly generating crack growth resistance curves. In this report, the model is applied to five specimen geometries which are known to give rise to significantly different crack tip constraints and crack growth resistance behaviors. Computed results are compared with sets of experimental data for two tough steels for four of the specimen types. Details of the load, displacement and crack growth histories are accurately reproduced, even when extensive crack growth takes place under conditions of fully plastic yielding. A description of material resistance to crack initiation and subsequent growth is essential for assessing structural integrity such as nuclear pressure vessels and piping

Growth, development and productivity of Jerusalem artichoke depending on plant stand in the conditions of the Republic of Karakalpakstan

Directory of Open Access Journals (Sweden)

Zhangabaeva A.S.

2017-08-01

Full Text Available the article presents the results of studying the influence of various schemes of planting seed tubers of Jerusalem artichoke on the rate of plant growth and development in the soil and climatic conditions of the Republic of Karakalpakstan. Differences in the rate of growth and development of plants are revealed, depending on the varietal features of Jerusalem artichoke and the density of their standing. The most optimal scheme for planting tubers of Jerusalem artichoke is 70x40 cm.

Microfibrous Matrices: Optimization of Synthesis Conditions

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Amogh N. Karwa

2012-01-01

Full Text Available This study focuses on the process of optimization for carbon nanofiber synthesis at the exterior and the interior of 3-dimensional sintered nickel microfibrous networks. Synthesis of carbon nanofibers (CNF by catalytic decomposition of acetylene (ethyne was conducted at atmospheric pressure and short reaction times (10 min. Two factors evaluated during the study were (a CNF quality (observed by SEM and Raman spectroscopy and (b rate of reaction (gravimetrically measured carbon yield. Independent optimization variables included redox faceting pretreatment of nickel, synthesis temperature, and gas composition. Faceting resulted in an 8-fold increase in the carbon yield compared to an untreated substrate. Synthesis with varying levels of hydrogen maximized the carbon yield (9.31 mg C/cm2 catalyst. The quality of CNF was enhanced via a reduction in amorphous carbon that resulted from the addition of 20% ammonia. Optimized growth conditions that led to high rates of CNF deposition preferentially deposited this carbon at the exterior layer of the nickel microfibrous networks (570°C, 78% H2, 20% NH3, 2% C2H2, faceted Ni.. CNF growth within the 3-dimensional nickel networks was accomplished at the conditions selected to lower the gravimetric reaction rate (470°C, 10% H2, 88% N2, 2% C2H2, nonfaceted Ni.

Constitutive Equation with Varying Parameters for Superplastic Flow Behavior

Science.gov (United States)

Guan, Zhiping; Ren, Mingwen; Jia, Hongjie; Zhao, Po; Ma, Pinkui

2014-03-01

In this study, constitutive equations for superplastic materials with an extra large elongation were investigated through mechanical analysis. From the view of phenomenology, firstly, some traditional empirical constitutive relations were standardized by restricting some strain paths and parameter conditions, and the coefficients in these relations were strictly given new mechanical definitions. Subsequently, a new, general constitutive equation with varying parameters was theoretically deduced based on the general mechanical equation of state. The superplastic tension test data of Zn-5%Al alloy at 340 °C under strain rates, velocities, and loads were employed for building a new constitutive equation and examining its validity. Analysis results indicated that the constitutive equation with varying parameters could characterize superplastic flow behavior in practical superplastic forming with high prediction accuracy and without any restriction of strain path or deformation condition, showing good industrial or scientific interest. On the contrary, those empirical equations have low prediction capabilities due to constant parameters and poor applicability because of the limit of special strain path or parameter conditions based on strict phenomenology.

EFFECT OF POLYETHYLENE BLACK PLASTIC MULCH ON GROWTH AND YIELD OF TWO SUMMER VEGETABLE CROPS UNDER RAIN-FED CONDITIONS UNDER SEMI-ARID REGION CONDITIONS

OpenAIRE

Atif Y. Mahadeen

2014-01-01

Water use efficiency in agriculture can be enhanced by several strategies mainly by reducing evaporation from the soil surface. The mulching techniques were being used widely in irrigated crop production worldwide. The mulching techniques can be also implemented in summer vegetables production under rain-fed conditions. The current study aimed at evaluating the effect of polyethylene black plastic mulch on growth and yield of okra, Abelmoschus esculentus and summer squash, ...