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Sample records for vole growth rates

  1. Bot fly parasitism of the red-backed vole: host survival, infection risk, and population growth.

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    Lemaître, Jérôme; Fortin, Daniel; Montiglio, Pierre-Olivier; Darveau, Marcel

    2009-03-01

    Parasites can play an important role in the dynamics of host populations, but empirical evidence remains sparse. We investigated the role of bot fly (Cuterebra spp.) parasitism in red-backed voles (Myodes gapperi) by first assessing the impacts of the parasite on the probability of vole survival under stressful conditions as well as on the reproductive activity of females. We then identified the main factors driving both the individual risk of infection and the abundance of bot flies inside red-backed voles. Finally, we evaluated the impacts of bot fly prevalence on the growth rate of vole populations between mid-July and mid-August. Thirty-six populations of red-backed voles were sampled in the boreal forest of Québec, Canada. The presence and the abundance of parasites in voles, two host life history traits (sex and body condition), three indices of habitat complexity (tree basal area, sapling basal area, coarse woody debris volume), and vole abundance were considered in models evaluating the effects of bot flies on host populations. We found that the probability of survival of red-backed voles in live traps decreased with bot fly infection. Both the individual risk of infection and the abundance of bot flies in red-backed voles were driven mainly by vole abundance rather than by the two host life history traits or the three variables of habitat complexity. Parasitism had population consequences: bot fly prevalence was linked to a decrease in short-term growth rate of vole populations over the summer. We found that bot flies have the potential to reduce survival of red-backed voles, an effect that may apply to large portions of populations.

  2. Plant phenolics as chemical defenses: Effects of natural phenolics on survival and growth of prairie voles (Microtus ochrogaster).

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    Lindroth, R L; Batzli, G O

    1984-02-01

    Very few studies have shown experimentally that plant chemical defenses actually reduce the performance of individual mammalian herbivores, much less the density of mammalian populations. We investigated the effects of representatives of three classes of plant phenoiics on the survival and growth of prairie voles by incorporating the compounds into artificial diets and feeding them to weanlings for three weeks. At low levels of protein, both quercetin (a flavonoid) and tannic acid (a hydrolyzable tannin) caused reduced growth rates; no effect occurred at high levels of protein. Quebracho (a condensed tannin) inhibited feeding and thus was lethal at all levels of protein. These results indicate that plant phenolics are likely to influence the performance and dynamics of natural populations of microtine rodents by reducing the quality of available forage. The hypothesis that the primary mode of action of the phenoiics is the reduction of digestibility of protein was not supported. The reduced growth caused by both quercetin and tannic acid could be attributed primarily to their toxicity. The effect of quebracho resulted from reduced intake (unpalatability).

  3. Silicon-based plant defences, tooth wear and voles.

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    Calandra, Ivan; Zub, Karol; Szafrańska, Paulina A; Zalewski, Andrzej; Merceron, Gildas

    2016-02-01

    Plant-herbivore interactions are hypothesized to drive vole population cycles through the grazing-induced production of phytoliths in leaves. Phytoliths act as mechanical defences because they deter herbivory and lower growth rates in mammals. However, how phytoliths impair herbivore performance is still unknown. Here, we tested whether the amount of phytoliths changes tooth wear patterns. If confirmed, abrasion from phytoliths could play a role in population crashes. We applied dental microwear texture analysis (DMTA) to laboratory and wild voles. Lab voles were fed two pelleted diets with differing amounts of silicon, which produced similar dental textures. This was most probably due to the loss of food mechanical properties through pelletization and/or the small difference in silicon concentration between diets. Wild voles were trapped in Poland during spring and summer, and every year across a population cycle. In spring, voles feed on silica-rich monocotyledons, while in the summer they also include silica-depleted dicotyledons. This was reflected in the results; the amount of silica therefore leaves a traceable record in the dental microwear texture of voles. Furthermore, voles from different phases of population cycles have different microwear textures. We tentatively propose that these differences result from grazing-induced phytolith concentrations. We hypothesize that the high amount of phytoliths in response to intense grazing in peak years may result in malocclusion and other dental abnormalities, which would explain how these silicon-based plant defences help provoke population crashes. DMTA could then be used to reconstruct vole population dynamics using teeth from pellets or palaeontological material. © 2016. Published by The Company of Biologists Ltd.

  4. Reproduction, aging and mortality rate in social subterranean mole voles (Ellobius talpinus Pall.).

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    Novikov, E; Kondratyuk, E; Petrovski, D; Titova, T; Zadubrovskaya, I; Zadubrovskiy, P; Moshkin, M

    2015-12-01

    Eusocial subterranean rodents of the Bathyergidae family have enormous longevity. The long lifespan of these species is associated with negligible senescence, that is, an absence of the signs of age-related deterioration in physical condition. The question arises as to whether these features are unique to eusocial Bathyergids or typical of other social subterranean rodents as well. In the present study, we analysed data from observations of a social subterranean Microtinae rodent, the northern mole vole (Ellobius talpinus Pall.), which, like mole-rats, has reproductive skew. Among the individuals captured in the wild and maintained in captivity, females that reproduced lived significantly longer than non-breeding females. We did not find any changes in muscle strength with age in any of the demographic groups studied. Faecal glucocorticoid concentrations before death were significantly higher in non-breeding females than in breeding females and males. Increased adrenocortical activity may be one mechanism responsible for the decreased lifespan of non-reproducing individuals of social subterranean rodents. We conclude that the patterns of aging, although different in some respects, are generally common for social subterranean rodents of different taxonomic groups.

  5. Frequency Population Growth Rate

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    Nouralah Salehi Asfiji

    2012-10-01

    Full Text Available The Solow growth model assumes that labor force grows exponentially. That is not a realistic assumption. In generalized logistic equations that describes more accurately population growth. Economic growth is not a smooth process. Real GDP has fluctuations in the growth rate. We call these fluctuations business cycles. Business cycle theory came about from the failures of classical economics in being able to illuminate on the causes of the Great Depression. The logistic growth model to explain changes in population growth rates are not. In this paper a new analysis of the population growth rate in the frequency space is described with mathematical logic and economic reasoning, so that, firstly, to a higher level of capital per capita, or at least equal to the Solow growth model reaches Second, the limits of saturation (Carrying-Capacity is not, and ultimately, population growth rates have an impact on long-term per capita amounts. The initial classic assumption is changed in this article based on the available frequencies in the population growth equation.

  6. EFFECTS OF PHOTOPERIOD ON GROWTH AND DEVELOPMENT OF PUPS IN BRANDT'S VOLES (MICROTUS BRANDTI)%光周期对布氏田鼠幼仔生长发育的影响

    Institute of Scientific and Technical Information of China (English)

    刘伟; 房继明

    2001-01-01

    Most of small mammals including Brandt's in temperate zone, voles(Microtus brandti), reproduce and rear offspring during seasons with mild environmental conditions and abundant food. It is assumed that animals bearing offspring during the breeding season increase their reproductive fitness and that reproduction at other periods results in fewer surviving progeny and possible energy crises for the parents. It, so that, is important that the environmental cues employed by animals to forecast the optimal breeding season are termed the proximate factors or cues of seasonal breeding. Photoperiod is the most common environmental factor used by north temperate mammals for timing reproduction. Brandt's voles' puberty and somatic growth are delayed by as many as 20 weeks in offspring late compared with early in the natural breeding season. The present study was the first measurement of some somatic and reproductive traits by comparing Brandt's voles pups born and housed in long (LD:14L:10D) versus short (SD:10L:14D) day photoperiod from birth to 28 days age or in 60 days age (The parents of LD and SD pups respectively housed exceeded 4 weeks in long and short day photoperiod after pairing). The goal was to determine whether photoperiod affect rate of growth and development of Brandt's voles offspring.   The results showed that photoperiod had no significant effect on the litter size at birth(t=1.21, df=18,P>0.05),the litter size at weaning(t=1.43,df=18,P>0.05) and the mean survival rate of pups per litter at weaning(t=1.38, df=18,P>0.05). Compared with SD pups, however, it is during eye-opening period (postnatal day 10~14) or after eye-opening (exceeded postnatal day 14) that LD offspring matured more rapidly with respect to body weight (W), body length (L) and relative fatness (Kwl=W/L) with the development of pups. Additionally, gonad-somatic index (GSI'=sin-1w\\-g/w×100%, Wg:gonad weight, W: body weight), including paired testes index (GSIt

  7. Prairie forb response to timing of vole herbivory.

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    Sullivan, Amy T; Howe, Henry F

    2009-05-01

    The timing of herbivory can be an important factor in the strength and direction of plant response to herbivore damage. To determine the effect of vole herbivory timing within a growing season on tallgrass prairie forbs, we used individual plant enclosures to limit vole access to three species, Desmanthus illinoensis, Echinacea purpurea, and Heliopsis helianthoides, in an experimental restoration in northern Illinois, USA. As part of a long-term experiment, we implemented five vole access treatments in 2003: (1) vole access for the entire growing season, (2) early-season access, (3) mid-season access, (4) late-season access, and (5) no vole access. We protected all plants from herbivory in the following growing season (2004) to test whether the effects of herbivory in one growing season carried over to the next. We also tested how restoration planting design, including seeding time (June or December) and density (35 or 350 seeds/m2 of each species) affected patterns of herbivory and plant recovery. Vole access for the entire growing season was most detrimental for the growth and reproduction of all three species. In contrast, vole access for a portion of the growing season had different effects on the three species: Desmanthus growth and reproduction was negatively affected by early-season access, Echinacea reproductive output was reduced by late-season access, and Heliopsis was not affected by early-, mid-, or late-season vole access. Negative effects of continual vole access carried over to the following growing season for Desmanthus and Heliopsis, but not for Echinacea. Effects of herbivory did not carry over to the next season for Echinacea and Heliopsis when plants were accessible to voles for only part of the growing season. In contrast, Desmanthus plants exposed to early-season herbivory in one year continued to produce fewer seeds per plant after being protected from vole herbivory for a growing season. Planting density and planting season had mixed effects

  8. How expensive is vole damage?

    OpenAIRE

    Walther, B; Fülling, O.; Malevez, J.; Pelz, H.-J.

    2008-01-01

    Vole species, especially Arvicola terrestris and Microtus arvalis cause significant economical damage in organic pomiculture by gnawing the root system of trees. The importance of voles as pest organisms is well known. Nevertheless, the estimation of financial loss caused by voles is difficult for German fruit growers. We conducted a survey among organic fruit growers to get data on kind and amount of annual damage. Using the available publications and official statistics we calculated econom...

  9. Growth rate for blackhole instabilities

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    Prabhu, Kartik; Wald, Robert

    2015-04-01

    Hollands and Wald showed that dynamic stability of stationary axisymmetric black holes is equivalent to positivity of canonical energy on a space of linearised axisymmetric perturbations satisfying certain boundary and gauge conditions. Using a reflection isometry of the background, we split the energy into kinetic and potential parts. We show that the kinetic energy is positive. In the case that potential energy is negative, we show existence of exponentially growing perturbations and further obtain a variational formula for the growth rate.

  10. Vole preference of bilberry along gradients of simulated moose density and site productivity.

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    Pedersen, Simen; Andreassen, Harry P; Persson, Inga-Lill; Julkunen-Tiitto, Riitta; Danell, Kjell; Skarpe, Christina

    2011-12-01

    Browsing by large herbivores might either increase or decrease preference for the plant by other herbivores, depending on the plant response. Using a cafeteria test, we studied the preference by root voles (Microtus oeconomus [Pallas, 1776]) for bilberry (Vaccinium myrtillus L.) previously subjected to 4 levels of simulated moose (Alces alces [Linnaeus, 1758]) density. The different levels of moose density were simulated at population densities relevant for Fennoscandian conditions, in exclosures situated along a site productivity gradient. We expected: (i) voles to prefer bilberry from high productivity sites over low productivity sites; (ii) voles to prefer browsed bilberry, if plants allocate resources to compensatory growth or to avoid browsed bilberry if plants allocate resources to defense; (iii) these effects to increase with increasing simulated moose density; and (iv) the concentration of plant chemicals and the plant morphology to explain vole preference. Specifically, we predicted that voles would prefer: (i) plants with high nitrogen content; (ii) plants with low content of defensive substances; and (iii) tall plants with long shoots. Voles preferred bilberry from the high productivity sites compared to the low productivity sites. We also found an interaction between site productivity and simulated moose density, where voles preferred unbrowsed plants at low productivity sites and intermediate levels of browsing at high productivity sites. There was no effect of plant chemistry or morphology on vole preference. We conclude that moose browsing impacts the food preference of voles. With the current high densities of moose in Fennoscandia, this could potentially influence vole food selection and population dynamics over large geographical areas.

  11. The evolutionary radiation of Arvicolinae rodents (voles and lemmings: relative contribution of nuclear and mitochondrial DNA phylogenies

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    Paradis Emmanuel

    2006-10-01

    Full Text Available Abstract Background Mitochondrial and nuclear genes have generally been employed for different purposes in molecular systematics, the former to resolve relationships within recently evolved groups and the latter to investigate phylogenies at a deeper level. In the case of rapid and recent evolutionary radiations, mitochondrial genes like cytochrome b (CYB are often inefficient for resolving phylogenetic relationships. One of the best examples is illustrated by Arvicolinae rodents (Rodentia; Muridae, the most impressive mammalian radiation of the Northern Hemisphere which produced voles, lemmings and muskrats. Here, we compare the relative contribution of a nuclear marker – the exon 10 of the growth hormone receptor (GHR gene – to the one of the mitochondrial CYB for inferring phylogenetic relationships among the major lineages of arvicoline rodents. Results The analysis of GHR sequences improves the overall resolution of the Arvicolinae phylogeny. Our results show that the Caucasian long-clawed vole (Prometheomys schaposnikowi is one of the basalmost arvicolines, and confirm that true lemmings (Lemmus and collared lemmings (Dicrostonyx are not closely related as suggested by morphology. Red-backed voles (Myodini are found as the sister-group of a clade encompassing water vole (Arvicola, snow vole (Chionomys, and meadow voles (Microtus and allies. Within the latter, no support is recovered for the generic recognition of Blanfordimys, Lasiopodomys, Neodon, and Phaiomys as suggested by morphology. Comparisons of parameter estimates for branch lengths, base composition, among sites rate heterogeneity, and GTR relative substitution rates indicate that CYB sequences consistently exhibit more heterogeneity among codon positions than GHR. By analyzing the contribution of each codon position to node resolution, we show that the apparent higher efficiency of GHR is due to their third positions. Although we focus on speciation events spanning the last

  12. In vitro culture and in vitro fertilization techniques for prairie voles (Microtus ochrogaster).

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    Horie, Kengo; Hidema, Shizu; Hirayama, Takashi; Nishimori, Katsuhiko

    2015-08-07

    Prairie vole (Microtus ochrogaster) is a highly social animal and is a commonly used animal model for neuropsychopharmacological and psychiatric studies. To date, only a few reports on the development of transgenic prairie voles which was primarily due to the suboptimal development of assisted reproductive technology (ART) in prairie voles. Limitations in ART further hinder the development of genetically modified prairie voles such as the application of conventional gene targeting technologies using embryonic stem (ES) or induced pluripotent stem (iPS) cells to generate chimeric prairie voles. Moreover, recent advancement in genome-editing tools such as transcription activator-like effector nuclease (TALEN) and clustered regulatory interspaced short palindromic repeat (CRISPR)/Cas technology provide an unprecedented opportunity to create gene targeting animal model and the development of ART in prairie voles is necessary for future development of novel transgenic prairie vole model. We have established efficient method for in vitro embryo culture and sperm cryopreservation with high fertilization rate. In G-1 PLUS and G-2 PLUS sequential culture condition, 81.0% (# of Blastocysts/total n) of one-cell embryos developed to blastocysts. In contrary, no embryos were developed to blastocyst stage in KSOM medium (0/total # of embryos in culture). In vitro fertilization rate using fresh and frozen-thawed sperm was 32.6% and 29.3%, respectively. This is the first report of IVF using cryopreserved prairie vole sperm. We employed mouse IVF methods in prairie voles and optimize culture conditions using human G-1/G-2 PLUS sequential culture method that resulted in high embryonic development rate. The development in vole reproductive technology will facilitate the generation of transgenic voles in the future.

  13. Methods of modelling relative growth rate

    Institute of Scientific and Technical Information of China (English)

    Arne Pommerening; Anders Muszta

    2015-01-01

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

  14. Methods of modelling relative growth rate

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    Arne Pommerening

    2015-03-01

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

  15. Effects of short term bioturbation by common voles on biogeochemical soil variables.

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    Burkhard Wilske

    Full Text Available Bioturbation contributes to soil formation and ecosystem functioning. With respect to the active transport of matter by voles, bioturbation may be considered as a very dynamic process among those shaping soil formation and biogeochemistry. The present study aimed at characterizing and quantifying the effects of bioturbation by voles on soil water relations and carbon and nitrogen stocks. Bioturbation effects were examined based on a field set up in a luvic arenosol comprising of eight 50 × 50 m enclosures with greatly different numbers of common vole (Microtus arvalis L., ca. 35-150 individuals ha-1 mth-1. Eleven key soil variables were analyzed: bulk density, infiltration rate, saturated hydraulic conductivity, water holding capacity, contents of soil organic carbon (SOC and total nitrogen (N, CO2 emission potential, C/N ratio, the stable isotopic signatures of 13C and 15N, and pH. The highest vole densities were hypothesized to cause significant changes in some variables within 21 months. Results showed that land history had still a major influence, as eight key variables displayed an additional or sole influence of topography. However, the δ15N at depths of 10-20 and 20-30 cm decreased and increased with increasing vole numbers, respectively. Also the CO2 emission potential from soil collected at a depth of 15-30 cm decreased and the C/N ratio at 5-10 cm depth narrowed with increasing vole numbers. These variables indicated the first influence of voles on the respective mineralization processes in some soil layers. Tendencies of vole activity homogenizing SOC and N contents across layers were not significant. The results of the other seven key variables did not confirm significant effects of voles. Thus overall, we found mainly a first response of variables that are indicative for changes in biogeochemical dynamics but not yet of those representing changes in pools.

  16. Spontaneous emergence of overgrown molar teeth in a colony of Prairie voles (Microtus ochrogaster)

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    Andrew H Jheon; Michaela Prochazkova; Michael Sherman; Devanand S Manoli; Nirao M Shah; Lawrence Carbone; Ophir Klein

    2015-01-01

    Continuously growing incisors are common to all rodents, which include the Microtus genus of voles. However, unlike many rodents, voles also possess continuously growing molars. Here, we report spontaneous molar defects in a population of Prairie voles (Microtus ochrogaster). We identified bilateral protuberances on the ventral surface of the mandible in several voles in our colony. In some cases, the protuberances broke through the cortical bone. The mandibular molars became exposed and infected, and the maxillary molars entered the cranial vault. Visualisation upon soft tissue removal and microcomputed tomography (microCT) analyses confirmed that the protuberances were caused by the overgrowth of the apical ends of the molar teeth. We speculate that the unrestricted growth of the molars was due to the misregulation of the molar dental stem cell niche. Further study of this molar phenotype may yield additional insight into stem cell regulation and the evolution and development of continuously growing teeth.

  17. The Optimum Growth Rate for Population Reconsidered

    OpenAIRE

    Jaeger, Klaus; Kuhle, Wolfgang

    2007-01-01

    This article gives exact general conditions for the existence of an interior optimum growth rate for population in the neoclassical two-generations-overlapping model. In an economy where high (low) growth rates of population lead to a growth path which is efficient (inefficient) there always exists an interior optimum growth rate for population. In all other cases there exists no interior optimum. The Serendipity Theorem, however, does in general not hold in an economy with government debt. M...

  18. The evolution of growth trajectories: what limits growth rate?

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    Dmitriew, Caitlin M

    2011-02-01

    According to life-history theory, growth rates are subject to strong directional selection due to reproductive and survival advantages associated with large adult body size. Yet, growth is commonly observed to occur at rates lower than the maximum that is physiologically possible and intrinsic growth rates often vary among populations. This implies that slower growth is favoured under certain conditions. Realized growth rate is thus the result of a compromise between the costs and advantages of growing rapidly, and the optimal rate of growth is not equivalent to the fundamental maximum rate. The ecological and evolutionary factors influencing growth rate are reviewed, with particular emphasis on how growth might be constrained by direct fitness costs. Costs of accelerating growth might contribute to the variance in fitness that is not attributable to age or size at maturity, as well as to the variation in life-history strategies observed within and among species. Two main approaches have been taken to study the fitness trade-offs relating to growth rate. First, environmental manipulations can be used to produce treatment groups with different rates of growth. Second, common garden experiments can be used to compare fitness correlates among populations with different intrinsic growth rates. Data from these studies reveal a number of potential costs for growth over both the short and long term. In order to acquire the energy needed for faster growth, animals must increase food intake. Accordingly, in many taxa, the major constraint on growth rate appears to arise from the trade-off between predation risk and foraging effort. However, growth rates are also frequently observed to be submaximal in the absence of predation, suggesting that growth trajectories also impact fitness via other channels, such as the reallocation of finite resources between growth and other traits and functions. Despite the prevalence of submaximal growth, even when predators are absent, there

  19. Modeling turkey growth with the relative growth rate.

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    Maruyama, K; Potts, W J; Bacon, W L; Nestor, K E

    1998-01-01

    Six sigmoidal growth curves and two growth curves derived from a two-phase relative growth rate model were evaluated, using an experimental body-weight data from male and female turkeys of two genetic lines; a fast-growing (F) line and a randombred control (RBC) line from which the F line was developed. When their root mean square error was compared to the root mean square error of the local regression smoother, all sigmoidal growth curves: the logistic, Gompertz, von Bertalanffy, Richards, Weibull, and Morgan-Mercer-Flodin growth curves demonstrated a lack of fit. The primary source of the systematic lack of fit was identified with nonparametric estimates of the relative growth rate (the growth rate as a fraction of the body weight) of 20 turkeys. When the relative growth rate was estimated from the above sigmoidal growth curves, none could accommodate features of the nonparametric estimates of the relative growth rate. Based on the feature of the relative growth rate, two new growth curves were derived from a segmented two-phase model. Both models, in which the relative growth rate decreases in two linear phases with slopes of beta1 and beta2 joined together at time=kappa, gave growth curves that fit the experimental data acceptably. The linear-linear model with the smooth transition rendered better fit over the model with the abrupt transition. When the growth curves of male and female turkeys were compared, beta1, beta2, and kappa were smaller in males. When the F line was compared to the RBC line, beta1 and kappa were smaller and beta2 was closer to zero, indicating that the relative growth rate declined rapidly until about 61 days of age in the F line, while it declined less rapidly until about 71 days of age in the RBC line.

  20. Genetics of Aggression in Voles

    OpenAIRE

    Gobrogge, Kyle L.; Wang, Zuoxin

    2011-01-01

    Prairie voles (Microtus ochrogaster) are socially monogamous rodents that form pair bonds—a behavior composed of several social interactions including attachment with a familiar mate and aggression toward conspecific strangers. Therefore, this species has provided an excellent opportunity for the study of pair bonding behavior and its underlying neural mechanisms. In this chapter, we discuss the utility of this unique animal model in the study of aggression and review recent findings illustra...

  1. A genetic linkage map and comparative mapping of the prairie vole (Microtus ochrogaster genome

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    Young Larry J

    2011-07-01

    Full Text Available Abstract Background The prairie vole (Microtus ochrogaster is an emerging rodent model for investigating the genetics, evolution and molecular mechanisms of social behavior. Though a karyotype for the prairie vole has been reported and low-resolution comparative cytogenetic analyses have been done in this species, other basic genetic resources for this species, such as a genetic linkage map, are lacking. Results Here we report the construction of a genome-wide linkage map of the prairie vole. The linkage map consists of 406 markers that are spaced on average every 7 Mb and span an estimated ~90% of the genome. The sex average length of the linkage map is 1707 cM, which, like other Muroid rodent linkage maps, is on the lower end of the length distribution of linkage maps reported to date for placental mammals. Linkage groups were assigned to 19 out of the 26 prairie vole autosomes as well as the X chromosome. Comparative analyses of the prairie vole linkage map based on the location of 387 Type I markers identified 61 large blocks of synteny with the mouse genome. In addition, the results of the comparative analyses revealed a potential elevated rate of inversions in the prairie vole lineage compared to the laboratory mouse and rat. Conclusions A genetic linkage map of the prairie vole has been constructed and represents the fourth genome-wide high-resolution linkage map reported for Muroid rodents and the first for a member of the Arvicolinae sub-family. This resource will advance studies designed to dissect the genetic basis of a variety of social behaviors and other traits in the prairie vole as well as our understanding of genome evolution in the genus Microtus.

  2. Field guide to red tree vole nests

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    Damon B. Lesmeister; James K. Swingle

    2017-01-01

    Surveys for red tree vole (Arborimus longicaudus) nests require tree climbing because the species is a highly specialized arboreal rodent that live in the tree canopy of coniferous forests in western Oregon and northwestern California. Tree voles are associated with old coniferous forest (≥80 years old) that are structurally complex, but are often...

  3. Measurements of Protein Crystal Face Growth Rates

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    Gorti, S.

    2014-01-01

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

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

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    Biswas, Dibyendu; Patra, Sankar Nayaran

    2015-01-01

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

  5. Volumetric Growth Rate of Recurrent Pleomorphic Adenoma.

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    Naunheim, Molly; Wu, Xin; Ryan, William R; Wang, Steven J; Heaton, Chase M

    2017-07-01

    Surgery for recurrent pleomorphic adenoma (PA) can be challenging and may increase the risk of operative complications, particularly facial nerve weakness. As observation may be a viable alternative to surgery for slow-growing tumors, our objective was to assess the growth rate of recurrent PAs. This study is a case series of patients at our tertiary academic medical center with recurrent PA. Two magnetic resonance images (MRI) were compared; total volume (TV) of recurrent tumor on both studies was calculated to obtain our main outcomes of percent change in TV and tumor growth rate. Fourteen patients with recurrent PA had a median interval time between MRI of 12.8 months. Though growth rates were variable, the median continuous compound growth per year was 10.2%. Notably, 3 patients (21%) had no growth, and 2 patients (14%) had a reduction in TV. The median growth rate for enlarging tumors is estimated at 10.2% per year. Due to variability, tumor growth rate should be estimated on an individual patient basis. For slow-growing tumors, physicians may weigh the risk of this slow growth with the morbidity of reoperation.

  6. Dinosaurian growth patterns and rapid avian growth rates.

    Science.gov (United States)

    Erickson, G M; Rogers, K C; Yerby, S A

    2001-07-26

    Did dinosaurs grow in a manner similar to extant reptiles, mammals or birds, or were they unique? Are rapid avian growth rates an innovation unique to birds, or were they inherited from dinosaurian precursors? We quantified growth rates for a group of dinosaurs spanning the phylogenetic and size diversity for the clade and used regression analysis to characterize the results. Here we show that dinosaurs exhibited sigmoidal growth curves similar to those of other vertebrates, but had unique growth rates with respect to body mass. All dinosaurs grew at accelerated rates relative to the primitive condition seen in extant reptiles. Small dinosaurs grew at moderately rapid rates, similar to those of marsupials, but large species attained rates comparable to those of eutherian mammals and precocial birds. Growth in giant sauropods was similar to that of whales of comparable size. Non-avian dinosaurs did not attain rates like those of altricial birds. Avian growth rates were attained in a stepwise fashion after birds diverged from theropod ancestors in the Jurassic period.

  7. On growth rate hysteresis and catastrophic crystal growth

    Science.gov (United States)

    Ferreira, Cecília; Rocha, Fernando A.; Damas, Ana M.; Martins, Pedro M.

    2013-04-01

    Different crystal growth rates as supersaturation is increasing or decreasing in impure media is a phenomenon called growth rate hysteresis (GRH) that has been observed in varied systems and applications, such as protein crystallization or during biomineralization. We have recently shown that the transient adsorption of impurities onto newly formed active sites for growth (or kinks) is sensitive to the direction and rate of supersaturation variation, thus providing a possible explanation for GRH [6]. In the present contribution, we expand on this concept by deriving the analytical expressions for transient crystal growth based on the energetics of growth hillock formation and kink occupation by impurities. Two types of GRH results are described according to the variation of kink density with supersaturation: for nearly constant density, decreasing or increasing supersaturation induce, respectively, growth promoting or inhibiting effects relative to equilibrium conditions. This is the type of GRH measured by us during the crystallization of egg-white lysozyme. For variable kink density, slight changes in the supersaturation level may induce abrupt variations in the crystal growth rate. Different literature examples of this so-called 'catastrophic' crystal growth are discussed in terms of their fundamental consequences.

  8. Accelerating Growth Rates in Shellfish with Bovine Growth Hormone

    OpenAIRE

    Chang, Ernest

    2002-01-01

    Marine biologist Dr.Ernest Chang of the Bodega Marine Laboratory and colleagues at the University of Hawaii investigated the possibility of using bovine growth hormone to increase growth rates of American lobster (Homarus americanus) and two species of shrimp—a cold-water California rock shrimp (Sicyonia ingentis) and the warm-water Penaeus vannamei.

  9. Does slower growth imply lower interest rates?

    OpenAIRE

    2014-01-01

    Over the past two years, both monetary and fiscal policy projections have been based on the view that declines in the long-run potential growth rate of the economy will in turn push down interest rates. In contrast, examination of private-sector professional forecasts and historical data provides little evidence of such a linkage. This suggests a greater risk that future interest rates may be higher than expected.

  10. Diabetes in Danish Bank Voles (M. glareolus)

    DEFF Research Database (Denmark)

    Schønecker, Bryan; Freimanis, Tonny; Sørensen, Irene Vejgaard

    2011-01-01

    , specificity, positive predictive value, and negative predictive value, equalled 69%, 97%, 89%, and 89%, respectively. The relatively long survival of Danish PD bank voles suggests potentials for this model in future studies of the long-term complications of diabetes, of which some observations are mentioned......Previous studies have concluded that the development of polydipsia (PD, a daily water intake ≥21 ml) among captive Danish bank voles, is associated with the development of a type 1 diabetes (T1D), based on findings of hyperglycaemia, glucosuria, ketonuria/-emia, lipemia, destroyed beta cells...... as a practical and non-invasive tool to screen for voles with a high probability of hypeglycaemia. In addition, we discuss regional differences related to the development of diabetes in Scandinavian bank voles and the relevance of the Ljungan virus as proposed etiological agent. We found that median survival...

  11. EVIDENCE ON EMPLOYMENT RATE AND ECONOMIC GROWTH

    Directory of Open Access Journals (Sweden)

    Cornelia VĂCEANU

    2014-11-01

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

  12. Enteric bacterial growth rates in river water.

    Science.gov (United States)

    Hendricks, C W

    1972-08-01

    Enteric bacteria, including stocked strains of pathogenic species and organisms naturally present in the stream, were capable of growth in a chemostat with autoclaved river water taken 750 m below a sewage outfall. Maximal specific growth rates for all organisms occurred at 30 C, whereas culture generation times ranged between 33.3 and 116 hr. Of the six laboratory strains of enteric species used, Escherichia coli and Enterobacter aerogenes grew at generation times of 34.5 and 33.3 hr, respectively, while the remaining Proteus, Arizona, Salmonella, and Shigella spp. reproduced at a rate two to three times slower than the coliforms. Little or no growth occurred in the water at incubation temperatures of 20 and 5 C, and death was observed for Salmonella senftenberg at 20 and 5 C and for E. aerogenes and Proteus rettgeri at 5 C. When enteric bacteria naturally present in the river water were employed in similar experiments, coliform bacteria demonstrated a generation time of approximately 116 hr, whereas fecal coliforms failed to grow. Growth of the bacteria from the river demonstrated a periodicity of approximately 100 hr, which suggests that much of the growth of these organisms in the chemostat may be on the glass surfaces. This phenomenon, however, was not observed with any of the stocked enteric species. Neither the stock cultures nor the aquatic strains were capable of growth in autoclaved river water taken above the sewage outfall at the three temperatures tested.

  13. Bounds on bacterial cell growth rates

    CERN Document Server

    Landy, Jonathan

    2013-01-01

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

  14. The Variance Composition of Firm Growth Rates

    Directory of Open Access Journals (Sweden)

    Luiz Artur Ledur Brito

    2009-04-01

    Full Text Available Firms exhibit a wide variability in growth rates. This can be seen as another manifestation of the fact that firms are different from one another in several respects. This study investigated this variability using the variance components technique previously used to decompose the variance of financial performance. The main source of variation in growth rates, responsible for more than 40% of total variance, corresponds to individual, idiosyncratic firm aspects and not to industry, country, or macroeconomic conditions prevailing in specific years. Firm growth, similar to financial performance, is mostly unique to specific firms and not an industry or country related phenomenon. This finding also justifies using growth as an alternative outcome of superior firm resources and as a complementary dimension of competitive advantage. This also links this research with the resource-based view of strategy. Country was the second source of variation with around 10% of total variance. The analysis was done using the Compustat Global database with 80,320 observations, comprising 13,221 companies in 47 countries, covering the years of 1994 to 2002. It also compared the variance structure of growth to the variance structure of financial performance in the same sample.

  15. Maximization of Growth Rates During Czochralski Pulling

    Science.gov (United States)

    Wargo, M. J.

    1984-01-01

    It was suggested from theory(1-4) that silicon can be grown from the melt at rates far exceeding the current state of the art. Previous theoretical and experimental investigations which predict maximum rates of pulling during Czochralski growth are reviewed. Several experimental methods are proposed to modify the temperature distribution in a growing crystal to achieve higher rates of pulling. A physical model of a Czochralski crystal of germanium in contact with its melt was used to quantitatively determine, by direct measurement of the axial temperature distribution in the solid, the increase in axial temperature gradients effected by an inverted conical heat reflector located above the melt and coaxially about the physical model. Preliminary results indicate that this is an effective method of increasing the thermal resistance between the hot melt and crucible wall and a growing crystal. Under these conditions the enhancement of the interfacial temperature gradients permit a commensurate increase in the rate of crystal pulling.

  16. China's fertility drop lowers world growth rate.

    Science.gov (United States)

    Haub, C

    1993-06-01

    China practices a stringent and compulsory program of family planning and population control. This approach has, however, served to increase the number of domestic IUD insertions and sterilizations. Contraceptive prevalence has reached 83% and total fertility (TFR) is estimated to be 1.9. This Chinese accomplishment has helped reduce TFR for all East Asia to 1.8, which is lower than that for northern Europe, and bring the world population growth rate down from the 1992 level of 1.68% to 1.63%. This latter rate is reported in the 1993 Population Reference Bureau's (PRB) World Population Data Sheet and is the lowest world population growth rate since PRB's first annual edition in 1962. Despite these reductions, world population still grows by 90 million annually. No one can say for sure whether or not observed fertility decline in China is permanent. China's birth rate rose twice in the 1980s and it could certainly rebound once again. A popular backlash to population policy or a relaxing of policy due to international pressure to reduce the level of compulsion in the program are 2 factors which might increase overall fertility and population growth. Fertility is also declining in subSaharan Africa, but not universally. Birth rates are rapidly declining in eastern Europe and the former USSR as economic conditions and outlooks pale. The populations of Estonia, Latvia, Ukraine, and possible Russia are even declining, while only mixed data are available from Yugoslavia. New statistical publications reflect changing borders. Finally, while Slovakia is the only country added to this year's sheet, Eritrea and the Channel Islands will likely be included in next year's.

  17. Experimental infection of meadow voles (Microtus pennsylvanicus) with sheep scrapie

    Science.gov (United States)

    Carlson, CM; Schneider, Jay R.; Pedersen, Janice C.; Heisey, Dennis M.; Johnson, Christopher J.

    2015-01-01

    Meadow voles (Microtus pennsylvanicus) are permissive to chronic wasting disease (CWD) infection, but their susceptibility to other transmissible spongiform encephalopathies (TSEs) is poorly characterized. In this initial study, we intracerebrally challenged 6 meadow voles with 2 isolates of sheep scrapie. Three meadow voles acquired a TSE after the scrapie challenge and an extended incubation period. The glycoform profile of proteinase K-resistant prion protein (PrP(res)) in scrapie-sick voles remained similar to the sheep inocula, but differed from that of voles clinically affected by CWD. Vacuolization patterns and disease-associated prion protein (PrP(Sc)) deposition were generally similar in all scrapie-affected voles, except in the hippocampus, where PrP(Sc) staining varied markedly among the animals. Our results demonstrate that meadow voles can acquire a TSE after intracerebral scrapie challenge and that this species could therefore prove useful for characterizing scrapie isolates.

  18. Experimental infection of meadow voles (Microtus pennsylvanicus) with sheep scrapie.

    Science.gov (United States)

    Carlson, Christina M; Schneider, Jay R; Pedersen, Joel A; Heisey, Dennis M; Johnson, Christopher J

    2015-01-01

    Meadow voles (Microtus pennsylvanicus) are permissive to chronic wasting disease (CWD) infection, but their susceptibility to other transmissible spongiform encephalopathies (TSEs) is poorly characterized. In this initial study, we intracerebrally challenged 6 meadow voles with 2 isolates of sheep scrapie. Three meadow voles acquired a TSE after the scrapie challenge and an extended incubation period. The glycoform profile of proteinase K-resistant prion protein (PrP(res)) in scrapie-sick voles remained similar to the sheep inocula, but differed from that of voles clinically affected by CWD. Vacuolization patterns and disease-associated prion protein (PrP(Sc)) deposition were generally similar in all scrapie-affected voles, except in the hippocampus, where PrP(Sc) staining varied markedly among the animals. Our results demonstrate that meadow voles can acquire a TSE after intracerebral scrapie challenge and that this species could therefore prove useful for characterizing scrapie isolates.

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

    Science.gov (United States)

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

    2009-02-01

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

  20. Species Diversity Enhances Predator Growth Rates

    Directory of Open Access Journals (Sweden)

    Mark H. Olson

    2007-01-01

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

  1. Growth rates of stratospheric HCFC-22

    Directory of Open Access Journals (Sweden)

    D. P. Moore

    2007-07-01

    Full Text Available The Michelson Interferometer for Passive Atmospheric Sounding onboard ENVISAT (MIPAS-E offers the opportunity to detect and spectrally resolve many atmospheric minor constituents affecting atmospheric chemistry. In this paper, we describe an algorithm produced to retrieve HCFC–22 profiles from MIPAS-E measurements made in 2003 and present results from this scheme between 300 and 50 mb. By comparison with ATMOS (AT–3 version 3 data, we find a mean Northern Hemisphere mid-latitude (20–50° N HCFC–22 growth rate between 1994 and 2003 of 5.4±0.7 pptv/yr in the lower stratosphere (LS and a mean LS Southern Hemisphere growth rate (60–80°S of 6.0±0.7 pptv/yr in the same period. We test the feasibility of using a global data set to estimate the chemical lifetime of HCFC–22 in the LS and we derive this for two regions; 20–50° N (259±38 years and 60–80° S (288±34 years. From these data we note a global LS lifetime of 274±25 years, significantly longer than previous estimates.

  2. [Ecology of indigenious arbovirus in Alsace. Tick Central European Encephalitis. I.--Complex Ixodes ricinus--bank voles. II.--Study of bank voles population immunity. III.--Virologic results in bank voles population (author's transl)].

    Science.gov (United States)

    Chatelain, J; Hannoun, C; Rodhain, F; Chatelain, J; Hannoun, C; Salmon, A M; Ardoin, P; Chatelain, J; Hannoun, C; Sureau, P

    1979-01-01

    I.--After showing that bank voles are parasited only by Ixodes ricinus larvae, the authors attempt to found different factors (demographic, biometric, and sexual) who favor individual parasitism. The authors conclude to absent of anti tick immunity for this rodent specie. II.--The search for anti-central european encephalitis antibodies (I.H.A.) are shown that 2 p. cent animals were immuns. Yearly and monthly chronologies of antibodies apparition are shown, factors favoring the growth of specific Central european encephalitis antibodies are discussed. III.--The Central european encephalitis tick viral infection of bank vole is studied according to the number of viral strains isolated from different viscera. The monthly chronology of this infection is shown.

  3. Taxonomic relationships among Phenacomys voles as inferred by cytochrome b

    Science.gov (United States)

    Bellinger, M.R.; Haig, S.M.; Forsman, E.D.; Mullins, T.D.

    2005-01-01

    Taxonomic relationships among red tree voles (Phenacomys longicaudus longicaudus, P. l. silvicola), the Sonoma tree vole (P. pomo), the white-footed vole (P. albipes), and the heather vole (P. intermedius) were examined using 664 base pairs of the mitochondrial cytochrome b gene. Results indicate specific differences among red tree voles, Sonoma tree voles, white-footed voles, and heather voles, but no clear difference between the 2 Oregon subspecies of red tree voles (P. l. longicaudus and P. l. silvicola). Our data further indicated a close relationship between tree voles and albipes, validating inclusion of albipes in the subgenus Arborimus. These 3 congeners shared a closer relationship to P. intermedius than to other arvicolids. A moderate association between porno and albipes was indicated by maximum parsimony and neighbor-joining phylogenetic analyses. Molecular clock estimates suggest a Pleistocene radiation of the Arborimus clade, which is concordant with pulses of diversification observed in other murid rodents. The generic rank of Arborimus is subject to interpretation of data.

  4. Puumala Virus in Bank Voles, Lithuania

    Science.gov (United States)

    Straková, Petra; Jagdmann, Sandra; Balčiauskas, Linas; Balčiauskienė, Laima; Drewes, Stephan

    2017-01-01

    Little is known about the presence of human pathogenic Puumala virus (PUUV) in Lithuania. We detected this virus in bank voles (Myodes glareolus) in a region of this country in which previously PUUV-seropositive humans were identified. Our results are consistent with heterogeneous distributions of PUUV in other countries in Europe. PMID:27983939

  5. Laboratory model of adaptive radiation: a selection experiment in the bank vole.

    Science.gov (United States)

    Sadowska, Edyta T; Baliga-Klimczyk, Katarzyna; Chrzaścik, Katarzyna M; Koteja, Paweł

    2008-01-01

    In a laboratory colony of a wild rodent, the bank vole Myodes (=Clethrionomys) glareolus, a multiway artificial selection experiment was applied to mimic evolution toward high aerobic metabolism achieved during locomotor activity, predatory behavior, and ability to cope with herbivorous diet. Four lines for each of the selection directions and four unselected control lines have been maintained. After three generations of within-family selection, the maximum rate of oxygen consumption achieved during swimming was 15% higher in the selected than in the control lines (least square means, adjusted for body mass: 252.0 vs. 218.6 mL O(2)/h, P = 0.0001). When fed a low-quality diet made of dried grass, voles from the lines selected for ability to cope with herbivorous diet lost about 0.7 g less mass than voles from the control lines (-2.44 vs. -3.16 g/4 d, P = 0.008). In lines selected for predatory behavior toward crickets, proportion of "predatory" individuals was higher than in the control lines (43.6% vs. 24.9%; P = 0.045), but "time to capture" calculated for the successful trials did not differ between the lines. The experiment continues, and the selected lines of voles will provide a unique model for testing hypotheses concerning correlated evolution of complex traits.

  6. Introgression of mitochondrial DNA among Myodes voles: consequences for energetics?

    Directory of Open Access Journals (Sweden)

    Boratyński Zbyszek

    2011-12-01

    Full Text Available Abstract Background Introgression of mitochondrial DNA (mtDNA is among the most frequently described cases of reticulate evolution. The tendency of mtDNA to cross interspecific barriers is somewhat counter-intuitive considering the key function of enzymes that it encodes in the oxidative-phosphorylation process, which could give rise to hybrid dysfunction. How mtDNA reticulation affects the evolution of metabolic functions is, however, uncertain. Here we investigated how morpho-physiological traits vary in natural populations of a common rodent (the bank vole, Myodes glareolus and whether this variation could be associated with mtDNA introgression. First, we confirmed that M. glareolus harbour mtDNA introgressed from M. rutilus by analyzing mtDNA (cytochrome b, 954 bp and nuclear DNA (four markers; 2333 bp in total sequence variation and reconstructing loci phylogenies among six natural populations in Finland. We then studied geographic variation in body size and basal metabolic rate (BMR among the populations of M. glareolus and tested its relationship with mtDNA type. Results Myodes glareolus and its arctic neighbour, M. rutilus, are reciprocally monophyletic at the analyzed nuclear DNA loci. In contrast, the two northernmost populations of M. glareolus have a fixed mitotype that is shared with M. rutilus, likely due to introgressive hybridization. The analyses of phenotypic traits revealed that the body mass and whole-body, but not mass corrected, BMR are significantly reduced in M. glareolus females from northern Finland that also have the introgressed mitotype. Restricting the analysis to the single population where the mitotypes coexist, the association of mtDNA type with whole-body BMR remained but those with mass corrected BMR and body mass did not. Mitochondrial sequence variation in the introgressed haplotypes is compatible with demographic growth of the populations, but may also be a result of positive selection. Conclusion Our

  7. GROWTH RATE DISTRIBUTION OF BORAX SINGLE CRYSTALS ON THE (001 FACE UNDER VARIOUS FLOW RATES

    Directory of Open Access Journals (Sweden)

    Suharso Suharso

    2010-06-01

    Full Text Available The growth rates of borax single crystals from aqueous solutions at various flow rates in the (001 direction were measured using in situ cell method. From the growth rate data obtained, the growth rate distribution of borax crystals was investigated using Minitab Software and SPSS Software at relative supersaturation of 0807 and temperature of 25 °C. The result shows that normal, gamma, and log-normal distribution give a reasonably good fit to GRD. However, there is no correlation between growth rate distribution and flow rate of solution.   Keywords: growth rate dispersion (GRD, borax, flow rate

  8. Temporal niche switching and reduced nest attendance in response to heat dissipation limits in lactating common voles (Microtus arvalis)

    NARCIS (Netherlands)

    van der Vinne, Vincent; Simons, Mirre J.P.; Reimert, Inonge; Gerkema, Menno P.

    2014-01-01

    According to the heat dissipation limit theory, maximum metabolic turnover is limited by the capacity of the body to dissipate excess heat. Small mammals, including common voles (Microtus arvalis), face a heat dissipation limitation during lactation. Pup growth and milk production are reduced under

  9. Vole and lemming activity observed from space

    Science.gov (United States)

    Olofsson, Johan; Tømmervik, Hans; Callaghan, Terry V.

    2012-12-01

    Predicting the impacts of present global warming requires an understanding of the factors controlling plant biomass and production. The extent to which they are controlled by bottom-up drivers such as climate, nutrient and water availability, and by top-down drivers such as herbivory and diseases in terrestrial systems is still under debate. By annually recording plant biomass and community composition in grazed control plots and in herbivore-free exclosures, at 12 sites in a subArctic ecosystem, we were able to show that the regular interannual density fluctuations of voles and lemmings drive synchronous interannual fluctuations in the biomass of field-layer vegetation. Plant biomass in the field layer was between 12 and 24% lower the year after a vole peak than the year before, and the combined vole and lemming peaks are visible as a reduced normalized difference vegetation index in satellite images over a 770km2 area in the following year, despite the wide range of abiotic, biotic and anthropogenic forces that influence the vegetation. This strongly suggests that the cascading effect of rodents for the function and diversity of tundra plant communities needs to be included in our scenarios of how these ecosystems will respond to environmental changes.

  10. EBSP studies of growth rates during recrystallization

    DEFF Research Database (Denmark)

    Juul Jensen, D.

    1996-01-01

    . The potential of the EBSP technique for both these types of measurements is illustrated for recrystallization of heavily deformed aluminium. It is discussed how these approaches apply to grain growth. Finally, new possibilities for in-situ grain growth studies by 3D mapping of orientations in the bulk...

  11. Sweat secretion rates in growth hormone disorders

    DEFF Research Database (Denmark)

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

    2000-01-01

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

  12. Sweat secretion rates in growth hormone disorders

    DEFF Research Database (Denmark)

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

    2000-01-01

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

  13. Calcite crystal growth rate inhibition by polycarboxylic acids

    Science.gov (United States)

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

    2001-01-01

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

  14. Are water vole resistant to anticoagulant rodenticides following field treatments?

    Science.gov (United States)

    Vein, Julie; Grandemange, Agnès; Cosson, Jean-François; Benoit, Etienne; Berny, Philippe J

    2011-08-01

    The anti-vitamin Ks (AVKs) are widely used to control rodent populations. They inhibit Vitamin K regeneration by the Vitamin K Epoxide Reductase (VKOR) and cause a fatal hemorrhagic syndrome. Because of repeated use, some populations of commensal rodents have expressed resistance to these compounds. In Franche-Comté (France), the water vole exhibits cyclic population outbreaks. A second generation AVK, bromadiolone, has been used for the last 20 years to control vole populations. The aim of this study is to determine whether these repeated treatments could have led to the development of resistance to AVKs in water vole populations. We conducted enzymatic and genetic studies on water voles trapped in treated and non treated plot. The results indicate that voles from the most heavily treated area exhibit enzymatic changes in VKOR activity hence arguing for resistance to AVKs and that an intronic haplotype on the vkorc1 gene seems to be associated with these enzymatic changes.

  15. (LAMINARIA PALLIDA) ON THE RE-GROWTH RATE AND ...

    African Journals Online (AJOL)

    user

    2010-05-05

    May 5, 2010 ... important factor affecting growth under laboratory conditions [9]. ... effects on light penetration, will affect the relative re-growth rate of sub-canopy kelp ..... photosynthesis and pigments in Laminaria ochroleuca (Laminariales,.

  16. Phenomenon in the Evolution of Voles (Mammalia, Rodentia, Arvicolidae

    Directory of Open Access Journals (Sweden)

    Rekovets L. I.

    2017-04-01

    Full Text Available This paper presents analytical results of the study of adaptatiogenesis within the family Arvicolidae (Mammalia, Rodentia based of morphological changes of the most functional characters of their masticatory apparatus — dental system — through time. The main directions of the morphological differentiation in parallel evolution of the arvicolid tooth type within the Cricetidae and Arvicolidae during late Miocene and Pliocene were identified and substantiated. It is shown that such unique morphological structure as the arvicolid tooth type has provided a relatively high rate of evolution of voles and a wide range of their adaptive radiation, as well as has determined their taxonomic and ecological diversity. The optimality of the current state of this group and evaluation of evolutionary prospects of Arvicolidae were presented and substantiated here as a phenomenon in their evolution.

  17. Economic growth rate management by soft computing approach

    Science.gov (United States)

    Maksimović, Goran; Jović, Srđan; Jovanović, Radomir

    2017-01-01

    Economic growth rate management is very important process in order to improve the economic stability of any country. The main goal of the study was to manage the impact of agriculture, manufacturing, industry and services on the economic growth rate prediction. Soft computing methodology was used in order to select the inputs influence on the economic growth rate prediction. It is known that the economic growth may be developed on the basis of combination of different factors. Gross domestic product (GDP) was used as economic growth indicator. It was found services have the highest impact on the GDP growth rate. On the contrary, the manufacturing has the smallest impact on the GDP growth rate.

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

    DEFF Research Database (Denmark)

    Hirst, Andrew G.; Keister, J. E.; Richardson, A. J.

    2014-01-01

    Estimating growth and production rates of mesozooplankton, and copepods in particular, is important in describing flows of material and energy though pelagic systems. Over the past 30 years, the Moult Rate (MR) method has been used to estimate juvenile copepod growth rates in ∼40 papers. Yet the ...

  19. Dependence of Limited Growth Rate of High-Quality Gem Diamond on Growth Conditions

    Institute of Scientific and Technical Information of China (English)

    TIAN Yu; MA Hong-An; LI Shang-Sheng; XIAO Hong-Yu; ZHANG Ya-Fei; HUANG Guo-Feng; MA Li-Qiu; JIA Xiao-Peng

    2007-01-01

    The growth rate of diamond has been investigated for a long time and researchers have been attempting to enhance the growth rate of high-quality gem diamond infinitely. However, it has been found according to previous research results that the quality of diamond is debased with the increase of growth rate. Thus, under specific conditions, the growth rate of high-quality diamond cannot exceed a limited value that is called the limited growth rate of diamond. We synthesize a series of type Ib gem diamonds by temperature gradient method under high pressure and high temperature (HPHT) using the as-grown {100} face. The dependence of limited growth rate on growth conditions is studied. The results show that the limited growth rate increases when synthetic temperature decreases, also when growth time is prolonged.

  20. Observational tests of Galileon gravity with growth rate

    Science.gov (United States)

    Hirano, Koichi

    2016-10-01

    We compare observational data of growth rate with the prediction by Galileon theory. For the same value of the energy density parameter Ω_{m,0}, the growth rate in Galileon models is enhanced compared with the Λ CDM case, due to the enhancement of Newton's constant. The smaller Ω_{m,0} is, the more suppressed growth rate is. Hence the best fit value of Ω_{m,0} in the Galileon model is 0.16 from only the growth rate data, which is considerably smaller than such value obtained from observations of supernovae Ia, the cosmic microwave background and baryon acoustic oscillations. We also find the upper limit of the Brans-Dicke parameter to be ω < -1000 (1σ ), from the growth rate data. In this paper, specific galileon models are considered, not the entire class. More and better growth rate data are required to distinguish between dark energy and modified gravity.

  1. Measurement of seedling growth rate by machine vision

    Science.gov (United States)

    Howarth, M. Scott; Stanwood, Phillip C.

    1993-05-01

    Seed vigor and germination tests have traditionally been used to determine deterioration of seed samples. Vigor tests describe the seed potential to emerge and produce a mature crop under certain field conditions and one measure is seedling growth rate. A machine vision system was developed to measure root growth rate over the entire germination period. The machine vision measurement technique was compared to the manual growth rate technique. The vision system provided similar growth rate measurements as compared to the manual growth rate technique. The average error between the system and a manual measurement was -0.13 for the lettuce test and -0.07 for the sorghum test. This technique also provided an accurate representation of the growth rate as well as percent germination.

  2. Near concavity of the growth rate for coupled LDPC chains

    CERN Document Server

    Hassani, S Hamed; Mori, Ryuhei

    2011-01-01

    Convolutional Low-Density-Parity-Check (LDPC) ensembles have excellent performance. Their iterative threshold increases with their average degree, or with the size of the coupling window in randomized constructions. In the later case, as the window size grows, the Belief Propagation (BP) threshold attains the maximum-a-posteriori (MAP) threshold of the underlying ensemble. In this contribution we show that a similar phenomenon happens for the growth rate of coupled ensembles. Loosely speaking, we observe that as the coupling strength grows, the growth rate of the coupled ensemble comes close to the concave hull of the underlying ensemble's growth rate. For ensembles randomly coupled across a window the growth rate actually tends to the concave hull of the underlying one as the window size increases. Our observations are supported by the calculations of the combinatorial growth rate, and that of the growth rate derived from the replica method. The observed concavity is a general feature of coupled mean field g...

  3. Resistive Wall Growth Rate Measurements in the Fermilab Recycler

    Energy Technology Data Exchange (ETDEWEB)

    Ainsworth, R. [Fermilab; Adamson, P. [Fermilab; Burov, A. [Fermilab; Kourbanis, I. [Fermilab

    2016-10-05

    Impedance could represent a limitation of running high intensity beams in the Fermilab recycler. With high intensity upgrades foreseen, it is important to quantify the impedance. To do this,studies have been performed measuring the growth rate of presumably the resistive wall instability. The growth rates at varying intensities and chromaticities are shown. The measured growth rates are compared to ones calculated with the resistive wall impedance.

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

    Science.gov (United States)

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

    2015-11-01

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

  5. Chromosomal evolution of Arvicolinae (Cricetidae, Rodentia). I. The genome homology of tundra vole, field vole, mouse and golden hamster revealed by comparative chromosome painting.

    Science.gov (United States)

    Sitnikova, Natalia A; Romanenko, Svetlana A; O'Brien, Patricia C M; Perelman, Polina L; Fu, Beiyuan; Rubtsova, Nadezhda V; Serdukova, Natalya A; Golenishchev, Feodor N; Trifonov, Vladimir A; Ferguson-Smith, Malcolm A; Yang, Fengtang; Graphodatsky, Alexander S

    2007-01-01

    Cross-species chromosome painting has become the mainstay of comparative cytogenetic and chromosome evolution studies. Here we have made a set of chromosomal painting probes for the field vole (Microtus agrestis) by DOP-PCR amplification of flow-sorted chromosomes. Together with painting probes of golden hamster (Mesocricetus auratus) and mouse (Mus musculus), the field vole probes have been hybridized onto the metaphases of the tundra vole (Microtus oeconomus). A comparative chromosome map between these two voles, golden hamster and mouse has been established based on the results of cross-species chromosome painting and G-banding comparisons. The sets of paints from the field vole, golden hamster and mouse identified a total of 27, 40 and 47 homologous autosomal regions, respectively, in the genome of tundra vole; 16, 41 and 51 fusion/fission rearrangements differentiate the karyotype of the tundra vole from the karyotypes of the field vole, golden hamster and mouse, respectively.

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

    NARCIS (Netherlands)

    Wilde-Duyfjes, de B.E.E.

    1967-01-01

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

  7. GROWTH-RATES OF SHRUBS ON DIFFERENT SOILS IN TANZANIA

    NARCIS (Netherlands)

    PRINS, HHT; VANDERJEUGD, HP

    1992-01-01

    Because little is known of growth rates of shrubs in East Africa, the growth rates of Acalypha fructicosa, Gardenia jovis-tonantis, Justicia cordata, Maerua triphylla, and Ocimum suave were measured in Lake Manyara National Park, northern Tanzania. Branch diameter increments and branch length increm

  8. Growth rates of Leucaena under different systems of tree management

    Energy Technology Data Exchange (ETDEWEB)

    Relwani, L.L.; Deshmukh, S.S.; Khandale, D.Y.; Nakat, R.V.

    1982-01-01

    L. leucocephala was planted at the BAIF campus (18.5 degrees N, 78.8 degrees E) at various spacings and grown with or without irrigation. Growth rates appeared to be satisfactory even under poor moisture conditions, but occasional irrigation during dry periods produced an increase in growth rates. Wider spacings had a greater influence on diameter on breast height than on height.

  9. Growth rates of intracranial aneurysms : exploring constancy

    NARCIS (Netherlands)

    Koffijberg, Hendrik; Buskens, Erik; Algra, Ale; Wermer, Marieke J. H.; Rinkel, Gabriel J. E.

    2008-01-01

    Object. The annual rate of rupture of intracranial aneurysms is often assumed to be constant, but it is unknown whether this assumption is true. Recent case reports have suggested that aneurysms grow fast in a short period of time. The authors of the present report investigated the plausibility of a

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  11. Are high real interest rates bad for world economic growth?

    OpenAIRE

    1991-01-01

    There is a conventional perception that high real interest rates are bad for economic growth. However, the authors show that close examination of the experience over the last 40 years undermines the existence of such a relationship. For much of the 1950-79 period, expost real interest rates were less than the growth rate of income in the major economies, whereas the 1980s were a period of rapid growth in the world economy that coincided withunprecedentedly high real interest rates. The author...

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

    Directory of Open Access Journals (Sweden)

    Jan Werner

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

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

    Science.gov (United States)

    Werner, Jan; Griebeler, Eva Maria

    2014-01-01

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

  14. Aortic growth rates in chronic aortic dissection

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, A.M. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States)]. E-mail: ainekell@med.umich.edu; Quint, L.E. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States); Nan, B. [School of Public Health, University of Michigan, Ann Arbor, Michigan (United States); Zheng, J. [School of Public Health, University of Michigan, Ann Arbor, Michigan (United States); Cronin, P. [Department of Radiology, Division of Thoracic Radiology, University of Michigan Medical Center (United States); Deeb, G.M. [Division of Cardiac Surgery, University of Michigan Medical Center (United States); Williams, D.M. [Division of Vascular Interventional Imaging, University of Michigan Medical Center (United States)

    2007-09-15

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

  15. The RNA chain elongation rate in Escherichia coli depends on the growth rate

    DEFF Research Database (Denmark)

    Vogel, Ulla; Jensen, Kaj Frank

    1994-01-01

    We determined the rates of mRNA and protein chain elongation on the lacZ gene during exponential growth on different carbon sources. The RNA chain elongation rate was calculated from measurements of the time elapsing between induction of lacZ expression and detection of specific hybridization...... with a probe near the 3' end of the mRNA. The elongation rate for the transcripts decreased 40% when the growth rate decreased by a factor of 4, and it always correlated with the rate of translation elongation. A similar growth rate dependency was seen for transcription on the infB gene and on a part...

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

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, P.F.

    1995-12-31

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

  17. Stimulation of serotonin (5-HT) activity reduces spontaneous stereotypies in female but not in male bank voles (Clethrionomys glareolus) Stereotyping female voles as a new animal model for human anxiety and mood disorders?

    DEFF Research Database (Denmark)

    Schønecker, Bryan; Heller, Knud Erik

    2003-01-01

    Bank voles, Stereotypies, Sex differences, Clozapine, Citalopram, Animal model, Anxiety, Mood disorders......Bank voles, Stereotypies, Sex differences, Clozapine, Citalopram, Animal model, Anxiety, Mood disorders...

  18. From Asymetrical Growth Rate Distributions to Multiple Normal Distributions

    Science.gov (United States)

    Žekić, A. A.; Mitrović, M. M.

    2007-04-01

    Growth rate dispersion (GRD) represents the variations in the growth rates of different crystals of the same material, grown under the same conditions. Mostly, these dispersions are decribed by asymetrical distributions with one maximum, and skeved to the right (log-normal and gamma). Recently, it was shown that the GRD of a crystals can be described by distributions with more maxima (multiple normal distribution). The analysis of the number and the height of the growth rate dispersions maxima has been performed. This analysis is shown the first or the second maximum has the maximal height, which results in asymetry of the distributions. This is the reason for the right GRD skeveness for the small number of crystal growth rates analysed. The results are discussed in accordance with crystal growth theories.

  19. [Helminth fauna of the bank vole myodes glareolus (Schreber, 1780) in the Kizhi Archipelago].

    Science.gov (United States)

    Bugmyrin, S V; Korosov, A V; Bespyatova, L A; Ieshko, E P

    2015-01-01

    The present study was aimed to examine the specific features of the helminth fauna in insular populations of the bank vole (Myodes glareolus) in the north of the species range. The material was collected in and nearby the Kizhi Archipelago (Lake Onega, 62°1' N 35°12' E) during August 1997, 2005-2007, 2012 and 2013. Small mammals were trapped on 23 islands (varying from 2 to 15,000 ha) and on the mainland. Helminthological met- hods were applied to examine 301 specimens of M glareolus. Fourteen helminth species were found: trematodes--Skrjabinoplagiorchis vigisi; cestodes--Paranoplocephala omphalodes, P. gracilis, Catenotaenia henttoneni, Taenia mustelae, Cladotaenia globife- ra, Spirometra erinacei; nematodes--Trichocephalus muris, Aonchotheca murissylvatici, Hepaticola hepatica, Heligmosomum mixtum, Heligmosomoides glareoli, Longistriata minuta, Syphacia petrusewiczi. The parasites S. vigisi, S. erinaci, H. hepatica and T. muris were identified in the bank vole in Karelia for the first time. Significant differences were detected between the helminth faunas of local insular populations of the bank vole. A distinctive feature of all small islands was that samples from them lacked the widespread pa- rasitic nematode Heligmosomum mixtum. The studies have confirmed the general trends observed in the parasite fauna of most isolated populations of small mammals: a poorer species diversity and high infestation rates with certain species of parasites. The Kizhi Archipelago is characterized by the specific high abundance of regionally rare parasite species (H hepatica, A. murissylvatici), and by the absence of common parasites (H. mixtum, H. glareoli).

  20. Adaptive evolution during an ongoing range expansion: the invasive bank vole (Myodes glareolus) in Ireland.

    Science.gov (United States)

    White, Thomas A; Perkins, Sarah E; Heckel, Gerald; Searle, Jeremy B

    2013-06-01

    Range expansions are extremely common, but have only recently begun to attract attention in terms of their genetic consequences. As populations expand, demes at the wave front experience strong genetic drift, which is expected to reduce genetic diversity and potentially cause 'allele surfing', where alleles may become fixed over a wide geographical area even if their effects are deleterious. Previous simulation models show that range expansions can generate very strong selective gradients on dispersal, reproduction, competition and immunity. To investigate the effects of range expansion on genetic diversity and adaptation, we studied the population genomics of the bank vole (Myodes glareolus) in Ireland. The bank vole was likely introduced in the late 1920s and is expanding its range at a rate of ~2.5 km/year. Using genotyping-by-sequencing, we genotyped 281 bank voles at 5979 SNP loci. Fourteen sample sites were arranged in three transects running from the introduction site to the wave front of the expansion. We found significant declines in genetic diversity along all three transects. However, there was no evidence that sites at the wave front had accumulated more deleterious mutations. We looked for outlier loci with strong correlations between allele frequency and distance from the introduction site, where the direction of correlation was the same in all three transects. Amongst these outliers, we found significant enrichment for genic SNPs, suggesting the action of selection. Candidates for selection included several genes with immunological functions and several genes that could influence behaviour.

  1. The effect of compensatory growth on feed intake, growth rate and ...

    African Journals Online (AJOL)

    after a time of feed restriction, restricted animals exhibit a growth rate ... change in composition of growth, which indicate that more protein but ..... fasting metabolism reached a maximum at about midsummer ..... The effects of weight loss and.

  2. Growth and development rates have different thermal responses.

    Science.gov (United States)

    Forster, Jack; Hirst, Andrew G; Woodward, Guy

    2011-11-01

    Growth and development rates are fundamental to all living organisms. In a warming world, it is important to determine how these rates will respond to increasing temperatures. It is often assumed that the thermal responses of physiological rates are coupled to metabolic rate and thus have the same temperature dependence. However, the existence of the temperature-size rule suggests that intraspecific growth and development are decoupled. Decoupling of these rates would have important consequences for individual species and ecosystems, yet this has not been tested systematically across a range of species. We conducted an analysis on growth and development rate data compiled from the literature for a well-studied group, marine pelagic copepods, and use an information-theoretic approach to test which equations best describe these rates. Growth and development rates were best characterized by models with significantly different parameters: development has stronger temperature dependence than does growth across all life stages. As such, it is incorrect to assume that these rates have the same temperature dependence. We used the best-fit models for these rates to predict changes in organism mass in response to temperature. These predictions follow a concave relationship, which complicates attempts to model the impacts of increasing global temperatures on species body size.

  3. Allometries of Maximum Growth Rate versus Body Mass at Maximum Growth Indicate That Non-Avian Dinosaurs Had Growth Rates Typical of Fast Growing Ectothermic Sauropsids

    OpenAIRE

    Jan Werner; Eva Maria Griebeler

    2014-01-01

    We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes) strongly differed from Case's study (1978), which...

  4. Lichen compounds restrain lichen feeding by bank voles (Myodes glareolus).

    Science.gov (United States)

    Nybakken, Line; Helmersen, Anne-Marit; Gauslaa, Yngvar; Selås, Vidar

    2010-03-01

    Some lichen compounds are known to deter feeding by invertebrate herbivores. We attempted to quantify the deterring efficiency of lichen compounds against a generalist vertebrate, the bank vole (Myodes glareolus). In two separate experiments, caged bank voles had the choice to feed on lichens with natural or reduced concentrations of secondary compounds. We rinsed air-dry intact lichens in 100% acetone to remove extracellular compounds non-destructively. In the first experiment, pairs of control and rinsed lichen thalli were hydrated and offered to the bank voles. Because the lichens desiccated fast, we ran a second experiment with pairs of ground control and compound-deficient thalli, each mixed with water to porridge. Eight and six lichen species were tested in the first and second experiment, respectively. In the first, bank voles preferred compound-deficient thalli of Cladonia stellaris and Lobaria pulmonaria, but did not discriminate between the other thallus pairs. This was likely a result of deterring levels of usnic and stictic acid in the control thalli. When lichens were served as porridge, significant preference was found for acetone-rinsed pieces of Cladonia arbuscula, C. rangiferina, Platismatia glauca, and Evernia prunastri. The increased preference was caused mainly by lower consumption of control thalli. Grinding and mixing of thallus structures prevented bank voles from selecting thallus parts with lower concentration of secondary compounds and/or strengthened their deterring capacity. We conclude that some lichen secondary compounds deter feeding by bank voles.

  5. Tree Growth Rates in the Periodically Flooded Great Dismal Swamp

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Tree diameter growth rates were measured in the Great Dismal Swamp, Virginia using vernier tree bands. Measurements were made in cypress, cedar, maple-gum, and mixed...

  6. Effect of different saccharides on growth, sporulation rate and d ...

    African Journals Online (AJOL)

    MFCS

    2012-05-17

    May 17, 2012 ... parasporal insecticidal crystal proteins (ICPs) known as δ-endotoxin and ... growth, sporulation rate and toxin production during cultivation using various ..... bacteria: choice of the carbon source and autoregulatory limitation of.

  7. Global evidence on the distribution of GDP growth rates

    Science.gov (United States)

    Williams, Michael A.; Baek, Grace; Li, Yiyang; Park, Leslie Y.; Zhao, Wei

    2017-02-01

    We study the size distribution of changes in the gross domestic product (GDP) of 167 countries for the period 1950-2011. A consensus has developed in the literature that the distribution of GDP growth rates can be approximated by the Laplace distribution in the central part and power-law distributions in the tails. Using a richer database than prior studies and testing for more theoretical distributions, we find that the distribution of GDP growth rates can be fitted using the heavy-tailed Cauchy distribution for almost all countries. Significantly, this same finding recently has been demonstrated for (1) the distribution of firm growth rates and (2) the distribution of firm economic profit rates. Together, these three findings suggest the possibility that there exist universal mechanisms that give rise to general laws governing the growth dynamics of firms and economies.

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

    DEFF Research Database (Denmark)

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

    2015-01-01

    -phase configurations are stabilized by adding a spring-like bias field coupling to an order-parameter that discriminates between the two phases. Crystal growth is a Smoluchowski process and the crystal growth rate can, therefore, be computed from the terminal exponential relaxation of the order parameter. The approach...... from first principles. A generalized version of the method may be used for computing the rates of crystal nucleation or other rare events....

  9. What determines the rate of growth and technological change?

    OpenAIRE

    ROMER, Paul M.

    1989-01-01

    There is substantial research about cross section and time series correlations between economic growth and various economic, social, demographic and political variables. After analyzing these correlations, the paper makes the following conclusions. Exogenous increases do not seem to cause increases in the rate of technological change, but instead seem to be associated with lower rates of return to capital. Increased openness to international trade speeds up growth and technological change as ...

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

    Science.gov (United States)

    Corkrey, Ross; McMeekin, Tom A; Bowman, John P; Ratkowsky, David A; Olley, June; Ross, Tom

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Ross Corkrey

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

  12. 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.

  13. Response of Escherichia coli growth rate to osmotic shock.

    Science.gov (United States)

    Rojas, Enrique; Theriot, Julie A; Huang, Kerwyn Casey

    2014-05-27

    It has long been proposed that turgor pressure plays an essential role during bacterial growth by driving mechanical expansion of the cell wall. This hypothesis is based on analogy to plant cells, for which this mechanism has been established, and on experiments in which the growth rate of bacterial cultures was observed to decrease as the osmolarity of the growth medium was increased. To distinguish the effect of turgor pressure from pressure-independent effects that osmolarity might have on cell growth, we monitored the elongation of single Escherichia coli cells while rapidly changing the osmolarity of their media. By plasmolyzing cells, we found that cell-wall elastic strain did not scale with growth rate, suggesting that pressure does not drive cell-wall expansion. Furthermore, in response to hyper- and hypoosmotic shock, E. coli cells resumed their preshock growth rate and relaxed to their steady-state rate after several minutes, demonstrating that osmolarity modulates growth rate slowly, independently of pressure. Oscillatory hyperosmotic shock revealed that although plasmolysis slowed cell elongation, the cells nevertheless "stored" growth such that once turgor was reestablished the cells elongated to the length that they would have attained had they never been plasmolyzed. Finally, MreB dynamics were unaffected by osmotic shock. These results reveal the simple nature of E. coli cell-wall expansion: that the rate of expansion is determined by the rate of peptidoglycan insertion and insertion is not directly dependent on turgor pressure, but that pressure does play a basic role whereby it enables full extension of recently inserted peptidoglycan.

  14. Measuring animal welfare within a reintroduction: an assessment of different indices of stress in water voles Arvicola amphibius.

    Directory of Open Access Journals (Sweden)

    Merryl Gelling

    Full Text Available Reintroductions are an increasingly common conservation restoration tool; however, little attention has hitherto been given to different methods for monitoring the stress encountered by reintroduced individuals. We compared ten potential measures of stress within four different categories (neuroendocrine, cell function, body condition and immune system function as proxies for animal welfare in water voles being reintroduced to the Upper Thames region, Oxfordshire, UK. Captive-bred voles were assessed pre-release, and each month post-release for up to five months. Wild-born voles were captured in the field and assessed from two months post-release. Plasma corticosteroid, hydration and body condition of captive-bred voles differed between their pre-release measures and both their first ("short-term" recapture, and their final recapture ("long-term" release, however only body condition and immunocompetence measured using the Nitroblue Tetrazolium (NBT test were significantly different post-release between the first and last recaptures. Captive-bred animals had lower fat reserves, higher weight/length ratios and better immunocompetence (NBT than did wild-born voles. Captive-bred males had higher ectoparasite burdens compared to wild-born males and, as reintroduction site quality decreased, became less hydrated. These observations indicate that some methods can identify changes in the stress response in individuals, highlighting areas of risk in a reintroduction programme. In addition, a single measure may not provide a full picture of the stress experienced; instead, a combination of measures of different physiological systems may give a more complete indication of stress during the reintroduction process. We highlight the need to monitor stress in reintroductions using measures from different physiological systems to inform on possible animal welfare improvements and thus the overall success rate of reintroductions.

  15. SPATULA links daytime temperature and plant growth rate.

    Science.gov (United States)

    Sidaway-Lee, Kate; Josse, Eve-Marie; Brown, Alanna; Gan, Yinbo; Halliday, Karen J; Graham, Ian A; Penfield, Steven

    2010-08-24

    Plants exhibit a wide variety of growth rates that are known to be determined by genetic and environmental factors, and different plants grow optimally at different temperatures, indicating that this is a genetically determined character. Moderate decreases in ambient temperature inhibit vegetative growth, but the mechanism is poorly understood, although a decrease in gibberellin (GA) levels is known to be required. Here we demonstrate that the basic helix-loop-helix transcription factor SPATULA (SPT), previously known to be a regulator of low temperature-responsive germination, mediates the repression of growth by cool daytime temperatures but has little or no growth-regulating role under warmer conditions. We show that only daytime temperatures affect vegetative growth and that SPT couples morning temperature to growth rate. In seedlings, warm temperatures inhibit the accumulation of the SPT protein, and SPT autoregulates its own transcript abundance in conjunction with diurnal effects. Genetic data show that repression of growth by SPT is independent of GA signaling and phytochrome B, as previously shown for PIF4. Our data suggest that SPT integrates time of day and temperature signaling to control vegetative growth rate.

  16. Effect of selection for relative growth rate and bodyweight of mice on rate, composition and efficiency of growth

    NARCIS (Netherlands)

    Bakker, H.

    1974-01-01

    To evaluate the effect of selection for parameters of a growth curve, four selection lines and a control line were started from one base population. In the selection lines is selected for a large and a small relative growth rate between 21 and 29 days (RGH and RGL) and for a large and small bodyweig

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

    Science.gov (United States)

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

    2014-09-01

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

  18. Seasonal growth rate of the sponge Haliclona oculata (Demospongiae: Haplosclerida).

    Science.gov (United States)

    Koopmans, Marieke; Wijffels, René H

    2008-01-01

    The interest in sponges has increased rapidly since the discovery of potential new pharmaceutical compounds produced by many sponges. A good method to produce these compounds by using aquaculture of sponges is not yet available, because there is insufficient knowledge about the nutritional needs of sponges. To gain more insight in the nutritional needs for growth, we studied the growth rate of Haliclona oculata in its natural environment and monitored environmental parameters in parallel. A stereo photogrammetry approach was used for measuring growth rates. Stereo pictures were taken and used to measure volumetric changes monthly during 1 year. Volumetric growth rate of Haliclona oculata showed a seasonal trend with the highest average specific growth rate measured in May: 0.012 +/- 0.004 day(-1). In our study a strong positive correlation (p rate with temperature, algal biomass (measured as chlorophyll a), and carbon and nitrogen content in suspended particulate matter. A negative correlation (p rate with salinity, ammonium, nitrate, nitrite, and phosphate. No correlation was found with dissolved organic carbon, suggesting that Haliclona oculata is more dependent on particulate organic carbon.

  19. Medium-dependent control of the bacterial growth rate.

    Science.gov (United States)

    Ehrenberg, Måns; Bremer, Hans; Dennis, Patrick P

    2013-04-01

    By combining results from previous studies of nutritional up-shifts we here re-investigate how bacteria adapt to different nutritional environments by adjusting their macromolecular composition for optimal growth. We demonstrate that, in contrast to a commonly held view the macromolecular composition of bacteria does not depend on the growth rate as an independent variable, but on three factors: (i) the genetic background (i.e. the strain used), (ii) the physiological history of the bacteria used for inoculation of a given growth medium, and (iii) the kind of nutrients in the growth medium. These factors determine the ribosome concentration and the average rate of protein synthesis per ribosome, and thus the growth rate. Immediately after a nutritional up-shift, the average number of ribosomes in the bacterial population increases exponentially with time at a rate which eventually is attained as the final post-shift growth rate of all cell components. After a nutritional up-shift from one minimal medium to another minimal medium of higher nutritional quality, ribosome and RNA polymerase syntheses are co-regulated and immediately increase by the same factor equal to the increase in the final growth rate. However, after an up-shift from a minimal medium to a medium containing all 20 amino acids, RNA polymerase and ribosome syntheses are no longer coregulated; a smaller rate of synthesis of RNA polymerase is compensated by a gradual increase in the fraction of free RNA polymerase, possibly due to a gradual saturation of mRNA promoters. We have also analyzed data from a recent publication, in which it was concluded that the macromolecular composition in terms of RNA/protein and RNA/DNA ratios is solely determined by the effector molecule ppGpp. Our analysis indicates that this is true only in special cases and that, in general, medium adaptation also depends on factors other than ppGpp.

  20. Intraspecific variation in the energetics of the Cabrera vole.

    Science.gov (United States)

    Castellanos-Frías, Elena; García-Perea, Rosa; Gisbert, Julio; Bozinovic, Francisco; Virgós, Emilio

    2015-12-01

    Basal metabolic rate (BMR) is an intensively topic studied in ecophysiology for the purpose of understanding energy budgets of the species, variations of energy expenditure during their diary activities and physiological acclimatization to the environment. Establishing how the metabolism is assembled to the environment can provide valuable data to improve conservation strategies of endangered species. In this sense, metabolic differences associated to habitats have been widely reported in the interspecific level, however little is known about the intraspecific view of BMR under an environmental gradient. In this study, we researched the effect of the habitat on metabolic rate of an Iberian endemic species: Iberomys cabrerae. Animals were captured in different subpopulations of its altitudinal range and their MR was studied over a thermal gradient. MR was analyzed through a Linear Mixed Model (LMM) in which, in addition to thermal effects, the bioclimatic zone and sex also influenced the metabolism of the species. The beginning of thermoneutrality zone was set on 26.5°C and RMR was 2.3ml O2g(-1)h(-1), intermediate between both bioclimatic zones. Supramediterranean subpopulations started the Tlc earlier (24.9°C) and had higher RMR than the mesomediterranean ones (26.9°C). The thermal environment together with primary productivity conditions could explain this difference in the metabolic behaviour of the Cabrera voles.

  1. Autonomic substrates of the response to pups in male prairie voles.

    Directory of Open Access Journals (Sweden)

    William M Kenkel

    Full Text Available Caregiving by nonparents (alloparenting and fathers is a defining aspect of human social behavior, yet this phenomenon is rare among mammals. Male prairie voles (Microtus ochrogaster spontaneously exhibit high levels of alloparental care, even in the absence of reproductive experience. In previous studies, exposure to a pup was selectively associated with increased activity in oxytocin and vasopressin neurons along with decreased plasma corticosterone. In the present study, physiological, pharmacological and neuroanatomical methods were used to explore the autonomic and behavioral consequences of exposing male prairie voles to a pup. Reproductively naïve, adult male prairie voles were implanted with radiotransmitters used for recording ECG, temperature and activity. Males responded with a sustained increase in heart-rate during pup exposure. This prolonged increase in heart rate was not explained by novelty, locomotion or thermoregulation. Although heart rate was elevated during pup exposure, respiratory sinus arrhythmia (RSA did not differ between these males and males exposed to control stimuli indicating that vagal inhibition of the heart was maintained. Blockade of beta-adrenergic receptors with atenolol abolished the pup-induced heart rate increase, implicating sympathetic activity in the pup-induced increase in heart rate. Blockade of vagal input to the heart delayed the males' approach to the pup. Increased activity in brainstem autonomic regulatory nuclei was also observed in males exposed to pups. Together, these findings suggest that exposure to a pup activates both vagal and sympathetic systems. This unique physiological state (i.e. increased sympathetic excitation of the heart, while maintaining some vagal cardiac tone associated with male caregiving behavior may allow males to both nurture and protect infants.

  2. 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.

  3. Limits to sustained energy intake. XXIII. Does heat dissipation capacity limit the energy budget of lactating bank voles?

    Science.gov (United States)

    Sadowska, Edyta T; Król, Elżbieta; Chrzascik, Katarzyna M; Rudolf, Agata M; Speakman, John R; Koteja, Paweł

    2016-03-01

    Understanding factors limiting sustained metabolic rate (SusMR) is a central issue in ecological physiology. According to the heat dissipation limit (HDL) theory, the SusMR at peak lactation is constrained by the maternal capacity to dissipate body heat. To test that theory, we shaved lactating bank voles (Myodes glareolus) to experimentally elevate their capacity for heat dissipation. The voles were sampled from lines selected for high aerobic exercise metabolism (A; characterized also by increased basal metabolic rate) and unselected control lines (C). Fur removal significantly increased the peak-lactation food intake (mass-adjusted least square means ± s.e.; shaved: 16.3 ± 0.3 g day(-1), unshaved: 14.4 ± 0.2 g day(-1); Plines. Thus, the experimental evolution model did not reveal a difference in the limiting mechanism between animals with inherently different metabolic rates.

  4. Coral growth rates revisited after 31 years: what is causing lower extension rates in Acropora palmata?

    NARCIS (Netherlands)

    Bak, R.P.M.; Nieuwland, G.; Meesters, H.W.G.

    2009-01-01

    Linear extension of branches in the same Acropora palmata (Lamarck, 1816) population in Curaçao was measured, employing exactly the same methods, in 1971-1973 and in 2002-2004, and the resulting coral growth rates are compared. Linear growth shows the same pattern over seasons in both periods with g

  5. Geometry of shoot apical dome and distribution of growth rates

    Directory of Open Access Journals (Sweden)

    Jerzy Nakielski

    2014-01-01

    Full Text Available The distribution of the relative elementary rate of growth (RERG in apical domes of various shapes and patterns of displacement lines can be analytically examined. The geometry of these domes may be described by parabolas of n-th order, the variant of the distribution of linear growth rate should be established along any displacement line (e.g. along the axis and then the RERG can be studied as the function depending on the position coordinates and the parameter n. Such investigations of several aplical domes of various shapes have been performed. The results confirm the occurrence of the minimum of relative, elementary growth rate (in volume in the subapical region of the dome independently of the type of geometry (n parabola order.

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

    Science.gov (United States)

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

    2008-06-01

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

  7. Scaling of Growth Rate Volatility for Six Macroeconomic Variables

    Directory of Open Access Journals (Sweden)

    Boris Podobnik

    2012-06-01

    Full Text Available We study the annual growth rates of six macroeconomic variables: public debt, public health expenditures, exports of goods, government consumption expenditures, total exports of goods and services, and total imports of goods and services. For each variable, we find (i that the distribution of the growth rate residuals approximately follows a double exponential (Laplace distribution and (ii that the standard deviation of growth rate residuals scales according to the size of the variable as a power law, with a scaling exponent similar to the scaling exponent found for GDP [Economics Letters 60, 335 (1998]. We hypothesise that the volatility scaling we find for these GDP constituents causes the volatility scaling found in GDP data.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-01-13

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

  9. Kinship, dispersal and hantavirus transmission in bank and common voles.

    Science.gov (United States)

    Deter, J; Chaval, Y; Galan, M; Gauffre, B; Morand, S; Henttonen, H; Laakkonen, J; Voutilainen, L; Charbonnel, N; Cosson, J-F

    2008-01-01

    Hantaviruses are among the main emerging infectious agents in Europe. Their mode of transmission in natura is still not well known. In particular, social features and behaviours could be crucial for understanding the persistence and the spread of hantaviruses in rodent populations. Here, we investigated the importance of kinclustering and dispersal in hantavirus transmission by combining a fine-scale spatiotemporal survey (4 km2) and a population genetics approach. Two specific host-hantavirus systems were identified and monitored: the bank vole Myodes, earlier Clethrionomys glareolus--Puumala virus and the common vole Microtus arvalis--Tula virus. Sex, age and landscape characteristics significantly influenced the spatial distribution of infections in voles. The absence of temporal stability in the spatial distributions of viruses suggested that dispersal is likely to play a role in virus propagation. Analysing vole kinship from microsatellite markers, we found that infected voles were more closely related to each other than non-infected ones. Winter kin-clustering, shared colonies within matrilineages or delayed dispersal could explain this pattern. These two last results hold, whatever the host-hantavirus system considered. This supports the roles of relatedness and dispersal as general features for hantavirus transmission.

  10. Response of two prairie forbs to repeated vole herbivory.

    Science.gov (United States)

    Sullivan, Amy T; Howe, Henry F

    2011-04-01

    Vertebrate herbivores as diverse as ungulates, geese, and rabbits preferentially feed on plants that have previously experienced herbivory. Here, we ask whether smaller grassland "cryptic consumers" such as voles (Microtus ochrogaster and M. pennsylvanicus) preferentially clip (cut stems for access to leaves or seeds) or avoid previously clipped individuals of two tallgrass prairie species (Desmanthus illinoensis and Echinacea purpurea) within a growing season. Further, we ask how these plants respond to repeated clipping within a growing season, and whether the effects of this herbivory last into the subsequent growing season. Voles preferentially clipped stems of D. illinoensis and E. purpurea plants that had been previously clipped. The exception was indiscriminant clipping of stems of E. purpurea late in the growing season when its achenes, a favorite vole food, ripened. For D. illinoensis, repeated clipping resulted in a 59% reduction in biomass, 42% lower ratio of reproductive to vegetative biomass, and 57% fewer seeds produced per plant compared with unclipped plants. These effects lasted into the following growing season in which plants were protected from voles. In contrast, the only effect of repeated clipping for E. purpurea was that the number of achenes per plant was substantially reduced by three episodes of clipping. This effect did not carry over to the next growing season. Such differences in D. illinoensis and E. purpurea response to repeated stem clipping by voles offer insights into how these small rodents can effect major changes in composition and dominance in grassland communities.

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

    Indian Academy of Sciences (India)

    Koyel Bhattacharya; Debajyoti Das

    2008-06-01

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

  12. Fatigue crack growth rates of rotor steel at elevated temperatures

    Institute of Scientific and Technical Information of China (English)

    LIU Chang-hai; MA Li-juan; TANG Li-qiang

    2008-01-01

    Low fatigue samples were obtained from the outer edges of rotor steel (30CrlMolV) which had operated under different temperatures conditions.Based on this data,the effects of temperature on fatigue crack growth rates were investigated.This paper presents a derivation of the superposition expression of two natural logarithms governing crack growth rates and also discusses the relationship between a material's constants and temperature.These results can provide experimental and theoretical references for fatigue life design of root steel in steam turbines.

  13. Universality of thermodynamic constants governing biological growth rates.

    Directory of Open Access Journals (Sweden)

    Ross Corkrey

    Full Text Available BACKGROUND: Mathematical models exist that quantify the effect of temperature on poikilotherm growth rate. One family of such models assumes a single rate-limiting 'master reaction' using terms describing the temperature-dependent denaturation of the reaction's enzyme. We consider whether such a model can describe growth in each domain of life. METHODOLOGY/PRINCIPAL FINDINGS: A new model based on this assumption and using a hierarchical Bayesian approach fits simultaneously 95 data sets for temperature-related growth rates of diverse microorganisms from all three domains of life, Bacteria, Archaea and Eukarya. Remarkably, the model produces credible estimates of fundamental thermodynamic parameters describing protein thermal stability predicted over 20 years ago. CONCLUSIONS/SIGNIFICANCE: The analysis lends support to the concept of universal thermodynamic limits to microbial growth rate dictated by protein thermal stability that in turn govern biological rates. This suggests that the thermal stability of proteins is a unifying property in the evolution and adaptation of life on earth. The fundamental nature of this conclusion has importance for many fields of study including microbiology, protein chemistry, thermal biology, and ecological theory including, for example, the influence of the vast microbial biomass and activity in the biosphere that is poorly described in current climate models.

  14. Sea ice growth rates from tide-driven visible banding

    Science.gov (United States)

    Turner, Kate E.; Smith, Inga J.; Tison, Jean-Louis; Verbeke, Véronique; McGuinness, Mark; Ingham, Malcolm; Vennell, Ross; Trodahl, Joe

    2017-06-01

    In this paper, periodic tide-current-driven banding in a sea-ice core is demonstrated as a measure of the growth rate of first-year sea ice at congelation-ice depths. The study was performed on a core from the eastern McMurdo Sound, exploiting the well-characterized tidal pattern at the site. It points the way to a technique for determining early-season ice growth rates from late-season cores, in areas where under ice currents are known to be tidally dominated and the ice is landfast, thus providing data for a time of year when thin ice prevents direct thickness (and therefore growth rate) measurements. The measured results were compared to the growth-versus-depth predicted by a thermodynamic model.Plain Language SummaryIt is currently very difficult to measure sea-ice growth rates, due to the danger of traveling on thin ice early in the growing season. This paper introduces the use of tidal patterns to determine sea-ice growth rates at the end of the growing season, when ice cores can be taken. The technique utilizes the visible light and dark bands that are often present in sea ice near land, and are driven by changes in the tidal current beneath the ice. As well as being important for climate research, this method could contribute to the understanding biological ecosystems within the ice, by providing a method to date depths in an ice core where particular organisms are observed or samples taken.

  15. Description of Paranoplocephala yoccozi n. sp. (Cestoda: Anoplocephalidae from the snow vole Chionomys nivalis in France, with a review of anoplocephalid cestodes of snow voles in Europe

    Directory of Open Access Journals (Sweden)

    Haukisalmi V.

    2005-09-01

    Full Text Available We describe Paranoplocephala yoccozi n. sp. (Cestoda: Anoplocephalidae from the snow vole Chionomys nivalis in Bourg-Saint-Maurice, French Alps, compare it with several related species from rodents, and review the anoplocephalid cestodes of snow voles in Europe. Paranoplocephala yoccozi n. sp. is primarily distinguished from the related species by its large scolex of characteristic shape, robust neck region, and the structure of the cirrus sac, vitellarium and vagina. We show that the anoplocephalid cestodes of snow voles in Europe, representing the genera Anoplocephaloides and Paranoplocephala, include at least seven species. This fauna consists primarily of species that snow voles share with other voles inhabiting the high-mountain areas. Some of the species, including P. yoccozi n. sp., appear to have a very localized distribution, which is assumed to be a consequence of the historical fragmentation of snow vole populations.

  16. A generic mechanism for adaptive growth rate regulation.

    Directory of Open Access Journals (Sweden)

    Chikara Furusawa

    2008-01-01

    Full Text Available How can a microorganism adapt to a variety of environmental conditions despite the existence of a limited number of signal transduction mechanisms? We show that for any growing cells whose gene expression fluctuate stochastically, the adaptive cellular state is inevitably selected by noise, even without a specific signal transduction network for it. In general, changes in protein concentration in a cell are given by its synthesis minus dilution and degradation, both of which are proportional to the rate of cell growth. In an adaptive state with a higher growth speed, both terms are large and balanced. Under the presence of noise in gene expression, the adaptive state is less affected by stochasticity since both the synthesis and dilution terms are large, while for a nonadaptive state both the terms are smaller so that cells are easily kicked out of the original state by noise. Hence, escape time from a cellular state and the cellular growth rate are negatively correlated. This leads to a selection of adaptive states with higher growth rates, and model simulations confirm this selection to take place in general. The results suggest a general form of adaptation that has never been brought to light--a process that requires no specific mechanisms for sensory adaptation. The present scheme may help explain a wide range of cellular adaptive responses including the metabolic flux optimization for maximal cell growth.

  17. A generic mechanism for adaptive growth rate regulation.

    Science.gov (United States)

    Furusawa, Chikara; Kaneko, Kunihiko

    2008-01-01

    How can a microorganism adapt to a variety of environmental conditions despite the existence of a limited number of signal transduction mechanisms? We show that for any growing cells whose gene expression fluctuate stochastically, the adaptive cellular state is inevitably selected by noise, even without a specific signal transduction network for it. In general, changes in protein concentration in a cell are given by its synthesis minus dilution and degradation, both of which are proportional to the rate of cell growth. In an adaptive state with a higher growth speed, both terms are large and balanced. Under the presence of noise in gene expression, the adaptive state is less affected by stochasticity since both the synthesis and dilution terms are large, while for a nonadaptive state both the terms are smaller so that cells are easily kicked out of the original state by noise. Hence, escape time from a cellular state and the cellular growth rate are negatively correlated. This leads to a selection of adaptive states with higher growth rates, and model simulations confirm this selection to take place in general. The results suggest a general form of adaptation that has never been brought to light--a process that requires no specific mechanisms for sensory adaptation. The present scheme may help explain a wide range of cellular adaptive responses including the metabolic flux optimization for maximal cell growth.

  18. Growth rates of modern science: A bibliometric analysis

    CERN Document Server

    Bornmann, Lutz

    2014-01-01

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

  19. Cold exposure inhibits hypothalamic Kiss-1 gene expression, serum leptin concentration, and delays reproductive development in male Brandt's vole ( Lasiopodomys brandtii)

    Science.gov (United States)

    Zhang, Qiang; Lin, Yi; Zhang, Xue-Ying; Wang, De-Hua

    2015-06-01

    Cold commonly affects growth and reproductive development in small mammals. Here, we test the hypothesis that low ambient temperature will affect growth and puberty onset, associated with altered hypothalamic Kiss-1 gene expression and serum leptin concentration in wild rodents. Male Brandt's voles ( Lasiopodomys brandtii) were exposed to cold (4 ± 1 °C) and warm (23 ± 1 °C) conditions from the birth and sacrificed on different developmental stages (day 26, day 40, day 60, and day 90, respectively). Brandt's voles increased the thermogenic capacity of brown adipose tissue, mobilized body fat, decreased serum leptin levels, and delayed the reproductive development especially on day 40 in the cold condition. They increased food intake to compensate for the high energy demands in the cold. The hypothalamic Kiss-1 gene expression on day 26 was decreased, associated with lower wet testis mass and testis testosterone concentration on day 40, in the cold-exposed voles compared to that in the warm. Serum leptin was positively correlated with body fat, testis mass, and testosterone concentration. These data suggested that cold exposure inhibited hypothalamic Kiss-1 gene expression during the early stage of development, decreased serum leptin concentration, and delayed reproductive development in male Brandt's voles.

  20. Fungal-mediated multitrophic interactions--do grass endophytes in diet protect voles from predators?

    Directory of Open Access Journals (Sweden)

    Susanna Saari

    Full Text Available Plant-associated micro-organisms such as mycotoxin-producing endophytes commonly have direct negative effects on herbivores. These effects may be carried over to natural enemies of the herbivores, but this has been rarely explored. We examined how feeding on Neotyphodium endophyte infected (E+ and endophyte free (E- meadow ryegrass (Scherodonus pratensis affects body mass, population size and mobility of sibling voles (Microtus levis, and whether the diet mediates the vulnerability of voles to least weasel (Mustela nivalis nivalis predation. Because least weasels are known to be olfactory hunters, we also examined whether they are able to distinguish olfactory cues of voles fed on E+ and E- diets. Neither body mass of voles nor population size differed between diets. However, contrary to our prediction, least weasels preyed more often on voles fed with E- grass than on voles fed with E+ grass. The mobility of voles fed on E+ grass was reduced compared to voles fed on E- grass, but this effect was unrelated to risk of predation. Least weasels appeared unable to distinguish between excrement odours of voles between the two treatments. Our results suggest that consumption of endophytic grass is not directly deleterious to sibling voles. What's more, consumption of endophytes appears to be advantageous to voles by reducing risk of mammalian predation. Our study is thus the first to demonstrate an effect of plant-associated microbial symbionts on herbivore-predator interactions in vertebrate communities.

  1. Fungal-mediated multitrophic interactions--do grass endophytes in diet protect voles from predators?

    Science.gov (United States)

    Saari, Susanna; Sundell, Janne; Huitu, Otso; Helander, Marjo; Ketoja, Elise; Ylönen, Hannu; Saikkonen, Kari

    2010-03-24

    Plant-associated micro-organisms such as mycotoxin-producing endophytes commonly have direct negative effects on herbivores. These effects may be carried over to natural enemies of the herbivores, but this has been rarely explored. We examined how feeding on Neotyphodium endophyte infected (E+) and endophyte free (E-) meadow ryegrass (Scherodonus pratensis) affects body mass, population size and mobility of sibling voles (Microtus levis), and whether the diet mediates the vulnerability of voles to least weasel (Mustela nivalis nivalis) predation. Because least weasels are known to be olfactory hunters, we also examined whether they are able to distinguish olfactory cues of voles fed on E+ and E- diets. Neither body mass of voles nor population size differed between diets. However, contrary to our prediction, least weasels preyed more often on voles fed with E- grass than on voles fed with E+ grass. The mobility of voles fed on E+ grass was reduced compared to voles fed on E- grass, but this effect was unrelated to risk of predation. Least weasels appeared unable to distinguish between excrement odours of voles between the two treatments. Our results suggest that consumption of endophytic grass is not directly deleterious to sibling voles. What's more, consumption of endophytes appears to be advantageous to voles by reducing risk of mammalian predation. Our study is thus the first to demonstrate an effect of plant-associated microbial symbionts on herbivore-predator interactions in vertebrate communities.

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

    Directory of Open Access Journals (Sweden)

    Xuefei Li

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

  3. Measuring the growth rate of structure around cosmic voids

    Science.gov (United States)

    Hawken, A. J.; Michelett, D.; Granett, B.; Iovino, A.; Guzzo, L.

    2016-10-01

    Using an algorithm based on searching for empty spheres we identified 245 voids in the VIMOS Public Extragalactic Redshift Survey (VIPERS). We show how by modelling the anisotropic void-galaxy cross correlation function we can probe the growth rate of structure.

  4. Sales Growth Rate Forecasting Using Improved PSO and SVM

    Directory of Open Access Journals (Sweden)

    Xibin Wang

    2014-01-01

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

  5. Is the natural rate of growth exogenous?A comment

    Directory of Open Access Journals (Sweden)

    Luciano Boggio

    2002-05-01

    Full Text Available The authors comment a recent paper (Leon-Ledesma and Thirlwall 2000 – from now on LLTin which an interesting issue is raised concerning the notion of the natural rate of growth, first proposed by Sir Roy Harrod (1939.

  6. Is reproduction costly? No increase of oxidative damage in breeding bank voles.

    Science.gov (United States)

    Ołdakowski, Łukasz; Piotrowska, Zaneta; Chrzaácik, Katarzyna M; Sadowska, Edyta T; Koteja, Paweł; Taylor, Jan R E

    2012-06-01

    According to life-history theory, investment in reproduction is associated with costs, which should appear as decreased survival to the next reproduction or lower future reproductive success. It has been suggested that oxidative stress may be the proximate mechanism of these trade-offs. Despite numerous studies of the defense against reactive oxygen species (ROS) during reproduction, very little is known about the damage caused by ROS to the tissues of wild breeding animals. We measured oxidative damage to lipids and proteins in breeding bank vole (Myodes glareolus) females after rearing one and two litters, and in non-breeding females. We used bank voles from lines selected for high maximum aerobic metabolic rates (which also had high resting metabolic rates and food intake) and non-selected control lines. The oxidative damage was determined in heart, kidneys and skeletal muscles by measuring the concentration of thiobarbituric acid-reactive substances, as markers of lipid peroxidation, and carbonyl groups in proteins, as markers of protein oxidation. Surprisingly, we found that the oxidative damage to lipids in kidneys and muscles was actually lower in breeding than in non-breeding voles, and it did not differ between animals from the selected and control lines. Thus, contrary to our predictions, females that bred suffered lower levels of oxidative stress than those that did not reproduce. Elevated production of antioxidant enzymes and the protective role of sex hormones may explain the results. The results of the present study do not support the hypothesis that oxidative damage to tissues is the proximate mechanism of reproduction costs.

  7. Controlling protein crystal growth rate by means of temperature

    Energy Technology Data Exchange (ETDEWEB)

    SantamarIa-Holek, I; Gadomski, A [Institute of Mathematics and Physics, University of Technology and Life Sciences, PL-85796 Bydgoszcz (Poland); RubI, J M, E-mail: isholek.fc@gmail.com, E-mail: agad@utp.edu.pl, E-mail: mrubi@ub.edu [Departament de Fisica Fonamental, University of Barcelona, Av. Diagonal 647, E-08028 Barcelona (Spain)

    2011-06-15

    We have proposed a model to analyze the growth kinetics of lysozyme crystals/aggregates under non-isothermal conditions. The model was formulated through an analysis of the entropy production of the growth process which was obtained by taking into account the explicit dependence of the free energy on the temperature. We found that the growth process is coupled with temperature variations, resulting in a novel Soret-type effect. We identified the surface entropy of the crystal/aggregate as a decisive ingredient controlling the behavior of the average growth rate as a function of temperature. The behavior of the Gibbs free energy as a function of temperature is also analyzed. The agreement between theory and experiments is very good in the range of temperatures considered.

  8. Controlling protein crystal growth rate by means of temperature.

    Science.gov (United States)

    Sanamaría-Holek, I; Gadomski, A; Rubí, J M

    2011-06-15

    We have proposed a model to analyze the growth kinetics of lysozyme crystals/aggregates under non-isothermal conditions. The model was formulated through an analysis of the entropy production of the growth process which was obtained by taking into account the explicit dependence of the free energy on the temperature. We found that the growth process is coupled with temperature variations, resulting in a novel Soret-type effect. We identified the surface entropy of the crystal/aggregate as a decisive ingredient controlling the behavior of the average growth rate as a function of temperature. The behavior of the Gibbs free energy as a function of temperature is also analyzed. The agreement between theory and experiments is very good in the range of temperatures considered.

  9. Dependence of calcite growth rate and Sr partitioning on solution stoichiometry: Non-Kossel crystal growth

    NARCIS (Netherlands)

    Nehrke, G.; Reichart, G.-J.; Van Cappellen, P.; Meile, C.; Bijma, J.

    2007-01-01

    Seeded calcite growth experiments were conducted at fixed pH (10.2) and two degrees of supersaturation (Ω = 5, 16), while varying the Ca2+ to CO3 2- solution ratio over several orders of magnitude. The calcite growth rate and the incorporation of Sr in the growing crystals strongly depended on

  10. Ecological Niche Modelling of Bank Voles in Western Europe

    Directory of Open Access Journals (Sweden)

    Sara Amirpour Haredasht

    2013-01-01

    Full Text Available The bank vole (Myodes glareolus is the natural host of Puumala virus (PUUV in vast areas of Europe. PUUV is one of the hantaviruses which are transmitted to humans by infected rodents. PUUV causes a general mild form of hemorrhagic fever with renal syndrome (HFRS called nephropathia epidemica (NE. Vector-borne and zoonotic diseases generally display clear spatial patterns due to different space-dependent factors. Land cover influences disease transmission by controlling both the spatial distribution of vectors or hosts, as well as by facilitating the human contact with them. In this study the use of ecological niche modelling (ENM for predicting the geographical distribution of bank vole population on the basis of spatial climate information is tested. The Genetic Algorithm for Rule-set Prediction (GARP is used to model the ecological niche of bank voles in Western Europe. The meteorological data, land cover types and geo-referenced points representing the locations of the bank voles (latitude/longitude in the study area are used as the primary model input value. The predictive accuracy of the bank vole ecologic niche model was significant (training accuracy of 86%. The output of the GARP models based on the 50% subsets of points used for testing the model showed an accuracy of 75%. Compared with random models, the probability of such high predictivity was low (χ2 tests, p < 10−6. As such, the GARP models were predictive and the used ecologic niche model indeed indicates the ecologic requirements of bank voles. This approach successfully identified the areas of infection risk across the study area. The result suggests that the niche modelling approach can be implemented in a next step towards the development of new tools for monitoring the bank vole’s population.

  11. Proximate causes of adaptive growth rates: growth efficiency variation among latitudinal populations of Rana temporaria.

    Science.gov (United States)

    Lindgren, B; Laurila, A

    2005-07-01

    In ectothermic organisms, declining season length and lower temperature towards higher latitudes often select for latitudinal variation in growth and development. However, the energetic mechanisms underlying this adaptive variation are largely unknown. We investigated growth, food intake and growth efficiency of Rana temporaria tadpoles from eight populations along a 1500 km latitudinal gradient across Sweden. To gain an insight into the mechanisms of adaptation at organ level, we also examined variation in tadpole gut length. The tadpoles were raised at two temperatures (16 and 20 degrees C) in a laboratory common garden experiment. We found increased growth rate towards higher latitudes, regardless of temperature treatment. This increase in growth was not because of a higher food intake rate, but populations from higher latitudes had higher growth efficiency, i.e. they were more efficient at converting ingested food into body mass. Low temperature reduced growth efficiency most strongly in southern populations. Relative gut length increased with latitude, and tadpoles at low temperature tended to have longer guts. However, variation in gut length was not the sole adaptive explanation for increased growth efficiency as latitude and body length still explained significant amounts of variation in growth efficiency. Hence, additional energetic adaptations are probably involved in growth efficiency variation along the latitudinal gradient.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  13. Empathy in prairie voles: Is this the consolation prize?

    Science.gov (United States)

    Demas, Gregory E; Jasnow, Aaron M

    2016-12-01

    Although it is well known that humans and great apes are capable of engaging in consolation, an affiliative behavior directed toward distressed individuals, it has largely been assumed that this form of empathy was restricted to species possessing more complex cognitive functions. Recently, however, Burkett and colleagues (Science, 351, 375-378, 2016) have provided intriguing evidence that consolation behavior may be present in a socially monogamous rodent, the prairie vole. They also provide data to implicate the neuropeptide oxytocin in the regulation of this behavior, which suggests conserved neuroendocrine mechanisms between prairie voles and humans.

  14. Inferring time derivatives including cell growth rates using Gaussian processes

    Science.gov (United States)

    Swain, Peter S.; Stevenson, Keiran; Leary, Allen; Montano-Gutierrez, Luis F.; Clark, Ivan B. N.; Vogel, Jackie; Pilizota, Teuta

    2016-12-01

    Often the time derivative of a measured variable is of as much interest as the variable itself. For a growing population of biological cells, for example, the population's growth rate is typically more important than its size. Here we introduce a non-parametric method to infer first and second time derivatives as a function of time from time-series data. Our approach is based on Gaussian processes and applies to a wide range of data. In tests, the method is at least as accurate as others, but has several advantages: it estimates errors both in the inference and in any summary statistics, such as lag times, and allows interpolation with the corresponding error estimation. As illustrations, we infer growth rates of microbial cells, the rate of assembly of an amyloid fibril and both the speed and acceleration of two separating spindle pole bodies. Our algorithm should thus be broadly applicable.

  15. Scaling laws in the dynamics of crime growth rate

    Science.gov (United States)

    Alves, Luiz G. A.; Ribeiro, Haroldo V.; Mendes, Renio S.

    2013-06-01

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

  16. Scaling laws in the dynamics of crime growth rate

    CERN Document Server

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

    2013-01-01

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

  17. Protein Degradation Rate in Arabidopsis thaliana Leaf Growth and Development.

    Science.gov (United States)

    Li, Lei; Nelson, Clark J; Trösch, Josua; Castleden, Ian; Huang, Shaobai; Millar, A Harvey

    2017-02-01

    We applied (15)N labeling approaches to leaves of the Arabidopsis thaliana rosette to characterize their protein degradation rate and understand its determinants. The progressive labeling of new peptides with (15)N and measuring the decrease in the abundance of >60,000 existing peptides over time allowed us to define the degradation rate of 1228 proteins in vivo. We show that Arabidopsis protein half-lives vary from several hours to several months based on the exponential constant of the decay rate for each protein. This rate was calculated from the relative isotope abundance of each peptide and the fold change in protein abundance during growth. Protein complex membership and specific protein domains were found to be strong predictors of degradation rate, while N-end amino acid, hydrophobicity, or aggregation propensity of proteins were not. We discovered rapidly degrading subunits in a variety of protein complexes in plastids and identified the set of plant proteins whose degradation rate changed in different leaves of the rosette and correlated with leaf growth rate. From this information, we have calculated the protein turnover energy costs in different leaves and their key determinants within the proteome.

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

    Directory of Open Access Journals (Sweden)

    S. A. J Obansa

    2013-07-01

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

  19. Fatigue crack growth rate test using a frequency sweep method

    Institute of Scientific and Technical Information of China (English)

    Xun ZHOU; Xiao-li YU

    2008-01-01

    Fatigue crack propagation characteristics of a diesel engine crankshaft are studied by measuring the fatigue crack growth rate using a frequency sweep method on a resonant fatigue test rig. Based on the phenomenon that the system frequency will change when the crack becomes large, this method can be directly applied to a complex component or structure. Finite element analyses (FEAs) are performed to calibrate the relation between the frequency change and the crack size, and to obtain the natural frequency of the test rig and the stress intensity factor (SIF) of growing cracks. The crack growth rate i.e. da/dN-AK of each crack size is obtained by combining the testing-time monitored data and FEA results. The results show that the crack growth rate of engine crankshaft, which is a component with complex geometry and special surface treatment, is quite different from that of a pure material. There is an apparent turning point in the Paris's crack partition. The cause of the fatigue crack growth is also dis-cussed.

  20. New microbial growth factor

    Science.gov (United States)

    Bok, S. H.; Casida, L. E., Jr.

    1977-01-01

    A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

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

    Directory of Open Access Journals (Sweden)

    SAVU MIHAELA

    2013-02-01

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

  2. FINGERNAIL GROWTH RATE IN A NORMAL CHINESE POPULATION

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To investigate fingernail growth rate (FNGR) role in the physiological or pathological status of the fingernails in normal Chinese population. Methods The FNGR was measured with vernier caliper. The data of 1 595 fingernails from 208 normal Chinese subjects (including 96 men and 112 women; age ranging from 14 to 78 years) were analyzed. Results The average FNGR was (0.104±0.027) mm per day. Higher growth rates were observed in males than in females, in the young individuals than in the old individuals, in summer than in winter, and in the right hand than in the left hand, respectively. The FNGR differed among fingernails and decreased in order of precedence: middle fingernails, index fingernails or ring fingernails, thumb and little fingernails. Conclusion FNGR was significantly associated with age, gender and temperature. Different fingernail grew at an individual speed.

  3. Flute growth rate of plasma jet in mirror machine

    Science.gov (United States)

    Be'ery, I.; Seemann, O.; Goldstein, G.; Fisher, A.; Ron, A.

    2014-02-01

    The evolution of flute instability in a cold, high-density hydrogen plasma jet, injected into a mirror machine, is studied. The experiment was designed to minimize the interaction of the plasma with the walls, thus bringing it close to the ideal magnetic Rayleigh-Taylor instability conditions. The modal growth rate was measured in various settings to demonstrate the effects of the finite Larmor radius, Bohm diffusion, conductive limiter, biased limiter and neutral background gas. In this paper we will demonstrate that lowering the magnetic field increases stability, as does the insertion of a conducting ring. However, if the ring is biased, the stability is reduced due to inhomogeneous coupling between the plasma and the limiter. It was also found that heavy background gas dramatically reduces the flute instability growth rate.

  4. A rare large right atrial myxoma with rapid growth rate.

    Science.gov (United States)

    Kelly, Shawn C; Steffen, Kelly; Stys, Adam T

    2014-10-01

    Atrial myxomas are the most common benign intracavitary cardiac neoplasms. They most frequently occur in the left atrium. Right atrial tumors are rare, comprising 20 percent of myxomas achieving an incidence of 0.02 percent. Due to their rarity, right atrial tumor development and associated clinical symptoms has not been well described. The classical clinical triad for the presentation of left atrial myxomas--heart failure, embolic events, and constitutional symptoms--may not be applicable to right sided tumors. Also, natural development of myxoma is not well described, as surgical resection is the common practice. Previously ascribed growth rates of myxomas refer mostly to left atrial ones, as right atrial tumors are rare. We present a case of right atrial myxoma with growth rates exceeding those previously described.

  5. Slow growth rates of Amazonian trees: Consequences for carbon cycling

    Science.gov (United States)

    Vieira, Simone; Trumbore, Susan; Camargo, Plinio B.; Selhorst, Diogo; Chambers, Jeffrey Q.; Higuchi, Niro; Martinelli, Luiz Antonio

    2005-01-01

    Quantifying age structure and tree growth rate of Amazonian forests is essential for understanding their role in the carbon cycle. Here, we use radiocarbon dating and direct measurement of diameter increment to document unexpectedly slow growth rates for trees from three locations spanning the Brazilian Amazon basin. Central Amazon trees, averaging only ≈1mm/year diameter increment, grow half as fast as those from areas with more seasonal rainfall to the east and west. Slow growth rates mean that trees can attain great ages; across our sites we estimate 17-50% of trees with diameter >10 cm have ages exceeding 300 years. Whereas a few emergent trees that make up a large portion of the biomass grow faster, small trees that are more abundant grow slowly and attain ages of hundreds of years. The mean age of carbon in living trees (60-110 years) is within the range of or slightly longer than the mean residence time calculated from C inventory divided by annual C allocation to wood growth (40-100 years). Faster C turnover is observed in stands with overall higher rates of diameter increment and a larger fraction of the biomass in large, fast-growing trees. As a consequence, forests can recover biomass relatively quickly after disturbance, whereas recovering species composition may take many centuries. Carbon cycle models that apply a single turnover time for carbon in forest biomass do not account for variations in life strategy and therefore may overestimate the carbon sequestration potential of Amazon forests. PMID:16339903

  6. Impact of increased flow rate on specific growth rate of juvenile turbot (Scophthalmus maximus, Rafinesque 1810)

    NARCIS (Netherlands)

    Schram, E.; Verdegem, M.C.J.; Widjaja, R.T.O.B.H.; Kloet, C.J.; Foss, A.; Schelvis-Smit, A.A.M.

    2009-01-01

    The effect of flow rate on growth was investigated in juvenile turbot. Fish with a mean (SD) initial weight of 102 (10.4) g were reared at 6 different flow rates, equaling 1, 2, 3, 4, 6 or 8 tank volumes/h in 196 L tanks during 29 days at 18 ± 0.29 °C, a salinity of 18.0 ± 0.77¿ and a pH ranging

  7. Effect of growth rate and body mass on resting metabolic rate in galliform chicks

    NARCIS (Netherlands)

    Dietz, MW; Drent, RH

    1997-01-01

    In this study, we asked whether within-species variation in chick resting metabolic rate was related to variation in growth and whether this relationship changed during development in three galliform species (turkey, Meleagris gallopavo, guinea fowl, Numida meleagris, and Japanese quail, Coturnix co

  8. Microevolution of Puumala hantavirus during a complete population cycle of its host, the bank vole (Myodes glareolus.

    Directory of Open Access Journals (Sweden)

    Maria Razzauti

    Full Text Available Microevolution of Puumala hantavirus (PUUV was studied throughout a population cycle of its host, the bank vole (Myodes glareolus. We monitored PUUV variants circulating in the host population in Central Finland over a five-year period that included two peak-phases and two population declines. Of 1369 bank voles examined, 360 (26.3% were found infected with PUUV. Partial sequences of each of the three genome segments were recovered (approx. 12% of PUUV genome from 356 bank voles. Analyses of these sequences disclosed the following features of PUUV evolution: 1 nucleotide substitutions are mostly silent and deduced amino acid changes are mainly conservative, suggesting stabilizing selection at the protein level; 2 the three genome segments accumulate mutations at a different rate; 3 some of the circulating PUUV variants are frequently observed while others are transient; 4 frequently occurring PUUV variants are composed of the most abundant segment genotypes (copious and new transient variants are continually generated; 5 reassortment of PUUV genome segments occurs regularly and follows a specific pattern of segments association; 6 prevalence of reassortant variants oscillates with season and is higher in the autumn than in the spring; and 7 reassortants are transient, i.e., they are not competitively superior to their parental variants. Collectively, these observations support a quasi-neutral mode of PUUV microevolution with a steady generation of transient variants, including reassortants, and preservation of a few preferred genotypes.

  9. Bacterial growth on surfaces: Automated image analysis for quantification of growth rate-related parameters

    DEFF Research Database (Denmark)

    Møller, S.; Sternberg, Claus; Poulsen, L. K.

    1995-01-01

    species-specific hybridizations with fluorescence-labelled ribosomal probes to estimate the single-cell concentration of RNA. By automated analysis of digitized images of stained cells, we determined four independent growth rate-related parameters: cellular RNA and DNA contents, cell volume......, and the frequency of dividing cells in a cell population. These parameters were used to compare physiological states of liquid-suspended and surfacegrowing Pseudomonas putida KT2442 in chemostat cultures. The major finding is that the correlation between substrate availability and cellular growth rate found...

  10. Growth-rate periodicity of Streptomyces levoris during space flight

    Science.gov (United States)

    Rogers, T. D.; Brower, M. E.; Taylor, G. R.

    1977-01-01

    Streptomyces levoris provides a suitable biological test system to investigate the effects of space flight on the rhythms of vegetative and spore phase characteristics of both growth-rate periodicity and culture morphology during the pre-, in-, and post-flight periods of the Apollo-Soyuz Test Project. The objectives of the American participation were to study the effects of space flight on the biorhythms of Streptomyces levoris based on a comparison of the growth-rate periodicity of the vegetative and spore phase within each culture, to examine the possible alteration of spore morphology and development by SEM, and to compare the effects of a 12-hr phase shift on the periodic growth characteristics of this microorganism in cultures which were exchanged during the joint activities of the space flight. No uniform differences in the biorhythm of Streptomyces levoris during space flight were observed. It appears that the single most variable factor related to the experiment was the lack of temperature control for the space-flight specimens.

  11. Relationship Between Metabolic Rate and Organ Size in Brandt's Voles (Microtus brandti)%内蒙古草原布氏田鼠代谢率与身体器官的关系

    Institute of Scientific and Technical Information of China (English)

    宋志刚; 王德华

    2003-01-01

    动物代谢率存在差异的原因及其意义是进化生理学的一个核心问题.为了解代谢率的影响因素和功能意义,我们测定了不同驯化条件下布氏田鼠(Microtus brandti)的基础代谢率 (basal metabolic rate, BMR) 、日能量消耗(daily energy expenditure, DEE)和冷诱导的最大代谢率 (maximum metabolic rate, MMR) ,分析了动物体内11种器官、组织的重量与代谢率的关系.结果显示,排除温度、光照、食物质量和体重的影响后,BMR与心脏、肝脏、肾脏、胃和盲肠相关;DEE与心脏、肾脏、胃和盲肠相关;MMR与脑重显著负相关.这表明:在布氏田鼠体内存在着代谢活性器官,主要包括心脏、肝脏、肾脏、胃和盲肠,这些器官对BMR有较大的贡献.动物的能量周转水平与体内 "代谢机器"(metabolic machinery)的大小相关连,主要受到心脏、肾脏、胃和盲肠的影响.最大代谢率受脑重的影响.BMR与MMR的相关性不显著,而BMR与DEE的相关性显著,说明较高的BMR有助于维持较高的DEE,但不能维持较高的MMR.

  12. Prediction of the growth rates of VDEs in JET

    Science.gov (United States)

    Albanese, R.; Mattei, M.; Villone, F.

    2004-09-01

    In this paper we show that the effect of the saddle currents in the rigid sectors slows down the vertical instability of JET elongated plasmas with respect to estimates based on pure axisymmetric models. This, together with an accurate description of the passive structures, significantly improves the agreement between the theoretical predictions and the experimental results. Linearized models taking into account the three-dimensional effects of the eddy currents have been applied to various JET pulses; the growth rates have been estimated within an accuracy of less than 5% for plasmas with a growth time longer than 2 ms. This model can be used for JET and extended to ITER-FEAT to provide a reliable test bed for assessing the performance of the vertical control system and obtain an estimate of the loads on the structures during vertical displacement events (VDEs) and plasma disruptions.

  13. Empirical formulas for description of the fatigue crack growth rate

    Energy Technology Data Exchange (ETDEWEB)

    Rozumek, D. [Opole University of Technology, Faculty of Mechanical Engineering, Opole (Poland)

    2010-02-15

    The paper presents the test results obtained for fatigue crack growth in flat specimens subjected to bending. The tests were conducted for different loading amplitudes and different load ratios using the {delta}J parameter. Accuracy of description of the fatigue crack growth rate was tested with use of different empirical formulas. One-side restrained specimens made of 10HNAP steel were tested. In each tested specimen, there was the external notch 5 mm in depth, and the notch rounding radius was {rho}=0.2 mm. The tests were carried out at the fatigue test stand MZGS-100 under loading frequency 28.8 Hz. It has been found that the obtained results depend on the applied empirical formula. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  14. Global Changes And Tree Growth Rate In The Amazon Forest

    Science.gov (United States)

    Camargo, P. B.; Vieira, S. A.; Trumbore, S. E.

    2003-12-01

    A better understanding of the variations in the dynamics and structure of trees in tropical forests is necessary for predicting the potential for these ecosystems to lose or store carbon. In general, tropical forests have been treated as if all trees behaved similarly, and little is known about how forests vary across the large extent of the Amazon basin. Our data show large differences in forest structure, biomass, and tree growth rates among plots under study in three locations in Brazil: ZF-2 Bionte/Jacaranda plots \\(Manaus\\), Catuaba Reserve \\(Rio Branco\\), and Tapaj¢s National Forest \\(Santarém\\). These locations span an east-west transect of the Amazon basin with different dry-season lengths. The number of stems >10cm diameter and stocks of C in aboveground biomass are the highest in Manaus \\(626ha-1, 180.1Mg.C.ha-1\\), than Rio Branco \\(466ha-1, 122.1Mg.C.ha-1\\) or Santarém \\(460ha-1, 140.6Mg.C.ha-1\\). Estimates of mean annual accumulation of C ranged from 1.6 \\(Manaus\\) and 2.5 \\(Rio Branco\\) to 2.8Mg.C.ha-1.yr-1 \\(Santarém\\). Trees in the 10-30cm diameter-size showed the highest accumulation of C \\(38%, 55%, and 56% - Manaus, Rio Branco, and Santarém, respectively\\). Our results showed marked seasonal growth, with the highest growth rates in the wet-season and the lowest growth rates in the dry-season. This effect was most evident for trees with diameter >50cm. The comparison of the three areas investigated suggests that forests experiencing a longer dry-season have larger annual diameter growth increments for individual trees. Tree average age was larger in Manaus where the increment was smaller. In all the three areas it was found specimens with DBH smaller than 30cm, but with ages over 200 years. It was found a specimen of 17 cm of DBH and age of 920 years. The fact that small trees can reach old ages may alter the scope of the present forest management planning whose focus is tree species of economical interest and the time the

  15. [Mexico City: a new course in its growth rate].

    Science.gov (United States)

    Partida Bush, V

    1994-01-01

    Mexico City, like other large cities, has entered a phase of slower growth which has led to revision in the projected future population of the metropolitan area. Rapid and sustained growth at a rate of over 5% annually between 1921 and 1970 justified the UN projection of 31 million inhabitants by the year 2000. National projections were more conservative. If the goals of the National Population Council for internal migration were met, the population would be 23.4 million. The 1980 census showed that the population was slightly under 13 million, substantially below the 15 million projected for that year. The revised UN projection was 24.4 million in 2000, which would make Mexico City the world's largest urban conglomeration. The 1990 census indicated a population of 15 million in the Mexico City metropolitan area. The intense movement to Mexico City over the course of the twentieth century was due to the concentration of political, industrial, and financial activity, urban services and infrastructure, and public and private health, educational, and cultural facilities in the capital on the one hand, and the backwardness of many of the nation's other regions on the other. The abrupt decline in Mexico City's growth rate after 1970 was due to both fertility decline and decline in in-migration. The rate of out-migration has also increased. Government policies calling for decentralization of public and private enterprises and the near prohibition of new industries in the Valley of Mexico, together with growing problems in the quality of life, environment, and public safety in Mexico City have been factors in the slowing expansion. New projections based on existing trends are for a population of 17 million in the year 2000 and 18.4 million in 2010.

  16. The growth rate of symplectic homology and affine varieties

    CERN Document Server

    McLean, Mark

    2010-01-01

    We will show that the cotangent bundle of an integrally hyperbolic manifold is not symplectomorphic to any smooth affine variety. We will also show that the unit cotangent bundle of such a manifold is not Stein fillable by a Stein domain whose completion is symplectomorphic to a smooth affine variety. For instance, these results hold when our manifolds are simply connected with at least one Betti number greater than the corresponding Betti number of the n torus. We use an invariant called the growth rate of symplectic homology to prove this result.

  17. Bacterial growth on surfaces: Automated image analysis for quantification of growth rate-related parameters

    DEFF Research Database (Denmark)

    Møller, S.; Sternberg, Claus; Poulsen, L. K.

    1995-01-01

    A fast routine method for estimating bacterial cell growth rates by using the metachromatic dye acridine orange is described. The method allows simultaneous estimates of cellular RNA and DNA contents of single cells. Acridine orange staining can be used as a nonspecific supplement to quantitative...

  18. Female promiscuity and maternally dependent offspring growth rates in mammals.

    Science.gov (United States)

    Garratt, Michael; Brooks, Robert C; Lemaître, Jean-François; Gaillard, Jean-Michel

    2014-04-01

    Conflicts between family members are expected to influence the duration and intensity of parental care. In mammals, the majority of this care occurs as resource transfer from mothers to offspring during gestation and lactation. Mating systems can have a strong influence on the severity of familial conflict--where female promiscuity is prevalent, conflict is expected to be higher between family members, causing offspring to demand more resources. If offspring are capable of manipulating their mothers and receive resources in proportion to their demands, resource transfer should increase with elevated promiscuity. We tested this prediction, unexplored across mammals, using a comparative approach. The total durations of gestation and lactation were not related to testes mass, a reliable proxy of female promiscuity across taxa. Offspring growth during gestation, however, and weaning mass, were positively correlated with testes mass, suggesting that offspring gain resources from their mothers at faster rates when familial conflict is greater. During gestation, the relationship between offspring growth and testes mass was also related to placenta morphology, with a stronger relationship between testes mass and growth observed in species with a less invasive placenta. Familial conflict could have a pervasive influence on patterns of parental care in mammals. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  19. Modelling the loss of genetic diversity in vole populations in a spatially and temporally varying environment

    DEFF Research Database (Denmark)

    Topping, Christopher John; Østergaard, Siri; Pertoldi, Cino

    2003-01-01

    a genetically explicit individual-based model (IBM) coupled to a dynamic landscape model was used to obtain measures for the genetic status of simulated vole populations. The rate of loss of expected heterozygosity (He) was calculated for simulated populations using two levels of spatial and temporal...... heterogeneity. Results showed that both spatial and temporal heterogeneity exerted an influence on the rate of loss of genetic diversity, but the precise effect was a balance between the effects of population sub-structuring, the frequency of founder effects and population size. These were in turn related...... of heterozygosity was corrected for the harmonic mean of the population size, the rate of loss was almost identical in the four scenarios. Unlike classical genetic models, IBMs are flexible enough to mimic real population processes under a range of environmental and behavioural conditions. We conclude that IBMs...

  20. Development of genomic resources for the prairie vole (Microtus ochrogaster: construction of a BAC library and vole-mouse comparative cytogenetic map

    Directory of Open Access Journals (Sweden)

    Young Larry J

    2010-01-01

    Full Text Available Abstract Background The prairie vole (Microtus ochrogaster is a premier animal model for understanding the genetic and neurological basis of social behaviors. Unlike other biomedical models, prairie voles display a rich repertoire of social behaviors including the formation of long-term pair bonds and biparental care. However, due to a lack of genomic resources for this species, studies have been limited to a handful of candidate genes. To provide a substrate for future development of genomic resources for this unique model organism, we report the construction and characterization of a bacterial artificial chromosome (BAC library from a single male prairie vole and a prairie vole-mouse (Mus musculus comparative cytogenetic map. Results We constructed a prairie vole BAC library (CHORI-232 consisting of 194,267 recombinant clones with an average insert size of 139 kb. Hybridization-based screening of the gridded library at 19 loci established that the library has an average depth of coverage of ~10×. To obtain a small-scale sampling of the prairie vole genome, we generated 3884 BAC end-sequences totaling ~2.8 Mb. One-third of these BAC-end sequences could be mapped to unique locations in the mouse genome, thereby anchoring 1003 prairie vole BAC clones to an orthologous position in the mouse genome. Fluorescence in situ hybridization (FISH mapping of 62 prairie vole clones with BAC-end sequences mapping to orthologous positions in the mouse genome was used to develop a first-generation genome-wide prairie vole-mouse comparative cytogenetic map. While conserved synteny was observed between this pair of rodent genomes, rearrangements between the prairie vole and mouse genomes were detected, including a minimum of five inversions and 16 inter-chromosomal rearrangements. Conclusions The construction of the prairie vole BAC library and the vole-mouse comparative cytogenetic map represent the first genome-wide modern genomic resources developed for this

  1. Examining structural breaks and growth rates in international health expenditures.

    Science.gov (United States)

    Narayan, Paresh Kumar

    2006-09-01

    Over the last decade, there has been a growing interest in examining health expenditures. In this paper, we study the behaviour of health expenditures in the G3 countries (USA, the UK, and Japan) and three European countries (the UK, Switzerland and Spain) over the period 1960-2000 from a different perspective, in that we examine: (1) whether there is a common structural break in health expenditures across the G3 and European countries; (2) whether structural breaks have slowed down health expenditure growth rates in these countries or vice versa. Our main findings are that: (1) health expenditures share a common break in both bivariate and trivariate cases, and structural breaks and break intervals suggest that either one or a combination of events (second oil price shock, the 1987 stock market crash and/or recessions) have contributed to the commonality of break in health expenditures in the G3, while the oil price shocks have been instrumental in the commonality of breaks for the European countries; (2) except for the UK, structural breaks have slowed down growth rates in health expenditures for the USA, Japan, Switzerland and Spain.

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

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2015-01-01

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

  3. GROWTH RATE DISPERSION (GRD OF THE (010 FACE OF BORAX CRYSTALS IN FLOWING SOLUTION

    Directory of Open Access Journals (Sweden)

    Suharso Suharso

    2010-06-01

    Full Text Available The growth rates of borax crystals from aqueous solutions in the (010 direction at various flow rates were measured. The observed variations of the growth rate can be represented by a normal distribution.  It was found that there is no correlation between growth rate distribution and solution flow under these experimental conditions.   Keywords: Growth rate dispersion (GRD, borax, flow rate

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

    Science.gov (United States)

    Lough, Janice M; Cantin, Neal E

    2014-06-01

    The tropical ocean environment is changing at an unprecedented rate, with warming and severe tropical cyclones creating obvious impacts to coral reefs within the last few decades and projections of acidification raising concerns for the future of these iconic and economically important ecosystems. Documenting variability and detecting change in global and regional climate relies upon high-quality observational records of climate variables supplemented, prior to the mid-19th century, with reconstructions from various sources of proxy climate information. Here we review how annual density banding patterns that are recorded in the skeletons of massive reef-building corals have been used to document environmental change and impacts within coral reefs. Massive corals provide a historical perspective of continuous calcification processes that pre-date most ecological observations of coral reefs. High-density stress bands, abrupt declines in annual linear extension, and evidence of partial mortality within the skeletal growth record reveal signatures of catastrophic stress events that have recently been attributed to mass bleaching events caused by unprecedented thermal stress. Comparison of recent trends in annual calcification with century-scale baseline calcification rates reveals that the frequency of growth anomalies has increased since the late 1990s throughout most of the world's coral reef ecosystems. Continuous coral growth histories provide valuable retrospective information on the coral response to environmental change and the consequences of anthropogenic climate change. Co-ordinated efforts to synthesize and combine global calcification histories will greatly enhance our understanding of current calcification responses to a changing ocean. © 2014 Marine Biological Laboratory.

  5. Time-course of micronucleated erythrocytes in response to whole-body gamma irradiation in a model mammalian species, the bank vole (Clethrionomys glareolus, Schreber).

    Science.gov (United States)

    Smolich, Igor I; Savina, Natalya V; Ryabokon, Nadezhda I

    2011-01-01

    The time course of the formation of micronucleated polychromatic (MNPCEs) and normochromatic erythrocytes (MNNCEs) in the bone marrow of the bank vole (Clethrionomys glareolus, Schreber), a model mouse-like species, was studied using the standard micronucleus test at 0, 6, 12, 18, 24, 30, 36 and 48 hr following whole-body acute γ-irradiation at a dose of 0.5 Gy. Based on the existing literature on laboratory mice, it was suggested that such a dose will not have significant effect on erythroid cell proliferation in the bank vole and hence on the time course of the rise of micronucleated cells. In total, ∼905,000 polychromatic (PCEs) and normochromatic erythrocytes (NCEs) from 82 adult bank voles were analyzed. Although the mean frequencies of MNNCEs were too low to allow for the correct assessment of their time course, an analysis of PCEs showed an increasing rate of MNPCE appearance at 6 hr that reached a maximum at 18-24 hr after irradiation and subsequently decreased. Because the kinetics of MNPCEs reflects the process of erythropoiesis, the current results regarding the time points of appearance of radiation-induced MNPCEs provide the first information on the prolongation of one of the terminal stages of erythrocyte formation in bank vole specimens, namely the stage of maturation of PCEs from erythroblasts. Moreover, the observed time-course data, as well as the low-background frequencies of MNPCEs and characteristic level of PCEs response to radiation, showed similarities between the two model species: bank vole (this study) and laboratory mice (literature data).

  6. Study on the Relationship between Lamellar Spacing and Growth Rate in the Regular Eutectic Growth by Monte-Carlo Simulation

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A modified Monte-Carlo(MC) method to simulate the regular growth of binary eutectic alloys is presented. It is found that the growth rate has a linear dependence on the chemical potential difference between the solid and liquid; the relation between the lamellar spacing λ and growth rate R accords well with the prediction of Jackson-Hunt(JH)theory unless the growth rate is very Iow.

  7. BIOLOGY AND INTRINSIC GROWTH RATE OF EARWIG (Euborellia annulata

    Directory of Open Access Journals (Sweden)

    Nurnina Nonci

    2016-10-01

    Full Text Available Earwig (Euborellia annulata is a potential predator of corn borer (Ostrinia furnacalis, one of the most important pests of corn. To include the use of predator in integrated pest management (IPM to control the pest, it is necessary to understand the basic information of the predator. This study aimed to know biology and intrinsic growth rate of the predator feed on an artificial media (dog food. Ten pairs of newly emerging adults of the predator were placed in a small plastic container containing a mixture of soil and sand (1:1 v/v supplemented with an artificial food. The average temperature and relative humidity during the study were kept at 27.9-30.3oC and 76.7-92.3%, respectively. The biological aspects of the predator evaluated were number of eggs laid, hatched, and died, as well as its oviposition period and adult mortality. The intrinsic growth rate was studied from a group of 200 newly laid eggs and results were analyzed based on the method of Birch. The biological aspects study showed that number of eggs laid by a single female of E. annulata was 86-166, which were laid five times in a group of 9-45 eggs. The nymph consists of five instars. Length of nymphs varied ranging from 4 to 13 mm depends on their instar. The fifth instar nymph period was 4-6 days for female and 2-3 days for male. The period of first mating was shorter; the shortest was 2 minutes and the longest one was 70 minutes. Both male and female were able to do mating several times at an interval of several seconds or minutes. Pre-oviposition period was 6-13 days. The eggs were deposited five times, the first, second, third, fourth, and fifth oviposition period were 7-22 days, 7-21 days, 7-18 days, 11-18 days, and 11-21 days, respectively. The oviposition period was 32-59 days and postoviposition period was 21-51 days. Ratio between male and female was 1.4:1.0. The average natural mortality of E. annulata was 10.5% which means that 89.5% of deposited eggs hatched became

  8. [Specific growth rate and the rate of energy metabolism in the ontogenesis of axolotl, Ambystoma mexicanum (Amphibia: Ambystomatidae)].

    Science.gov (United States)

    Vladimirova, I G; Kleĭmenov, S Iu; Alekseeva, T A; Radzinskaia, L I

    2003-01-01

    Concordant changes in the rate of energy metabolism and specific growth rate of axolotls have been revealed. Several periods of ontogeny are distinguished, which differ in the ratio of energy metabolism to body weight and, therefore, are described by different allometric equations. It is suggested that the specific growth rate of an animal determines the type of dependence of energy metabolism on body weight.

  9. Dioxin exposure in contaminated sawmill area: the use of molar teeth and bone of bank vole (Clethrionomys glareolus) and field vole (Microtus agrestis) as biomarkers.

    Science.gov (United States)

    Murtomaa, Mari; Tervaniemi, Olli-Matti; Parviainen, Juha; Ruokojärvi, Päivi; Tuukkanen, Juha; Viluksela, Matti

    2007-06-01

    Developmental disorders of teeth are among the most sensitive targets of polychlorinated dibenzo-p-dioxin and -furan (PCDD/F) exposure. In rats, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) reduces dose-dependently the size of molars, most severely the third lower molars. Dioxins also have effects on developing bone, including altered bone mineral density as well as reduced bending breaking force and stiffness. The aim of this study was to evaluate the use of the third lower molar and long bones as biomarkers of PCDD/F exposure in two wild vole species, the bank vole (Clethrionomys glareolus) and the field vole (Microtus agrestis) collected from a PCDD/F contaminated former sawmill area. Survey of soil and biota of the sawmill area indicated a PCDD/F contamination with a congener profile characteristic for the chlorophenol wood preservative Ky-5. The PCDD/F concentration in the bank vole was notably higher than in the field vole. The third molar of the bank vole was significantly smaller in dioxin-exposed animals compared to control group, while there was no difference between these two groups in the field vole. No significant alterations were observed in bone density and strength in either species except for reduced bending strength of the femur neck in bank vole males exposed to dioxins. Even though the bone changes are among the sensitive endpoints of dioxin-exposure, high variability due to age, size and gender limits their use as biomarkers of wildlife exposure. In conclusion, the size of molar teeth seems to be a sensitive and robust biomarker for PCDD/F exposure in wild bank vole populations and thus worth of further studies.

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

    Science.gov (United States)

    Houghton, Jennie; Thompson, Ken; Rees, Mark

    2013-07-07

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

  11. Growth rate inhibition of phytopathogenic fungi by characterized chitosans

    Directory of Open Access Journals (Sweden)

    Enio N. Oliveira Junior

    2012-06-01

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

  12. Age, growth rates, and paleoclimate studies of deep sea corals

    Science.gov (United States)

    Prouty, Nancy G; Roark, E. Brendan; Andrews, Allen; Robinson, Laura; Hill, Tessa; Sherwood, Owen; Williams, Branwen; Guilderson, Thomas P.; Fallon, Stewart

    2015-01-01

    Deep-water corals are some of the slowest growing, longest-lived skeletal accreting marine organisms. These habitat-forming species support diverse faunal assemblages that include commercially and ecologically important organisms. Therefore, effective management and conservation strategies for deep-sea corals can be informed by precise and accurate age, growth rate, and lifespan characteristics for proper assessment of vulnerability and recovery from perturbations. This is especially true for the small number of commercially valuable, and potentially endangered, species that are part of the black and precious coral fisheries (Tsounis et al. 2010). In addition to evaluating time scales of recovery from disturbance or exploitation, accurate age and growth estimates are essential for understanding the life history and ecology of these habitat-forming corals. Given that longevity is a key factor for population maintenance and fishery sustainability, partly due to limited and complex genetic flow among coral populations separated by great distances, accurate age structure for these deep-sea coral communities is essential for proper, long-term resource management.

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

    Directory of Open Access Journals (Sweden)

    Hal Caswell

    2010-09-01

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

  14. Metabolism correlates with variation in post-natal growth rate among songbirds at three latitudes

    Science.gov (United States)

    Ton, Riccardo; Martin, Thomas E.

    2016-01-01

    1. Variation in post-natal growth rates is substantial among organisms and especially strong among latitudes because tropical and south temperate species typically have slower growth than north temperate relatives. Metabolic rate is thought to be a critical mechanism underlying growth rates after accounting for allometric effects of body mass. However, comparative tests on a large spatial scale are lacking, and the importance of metabolism for growth rates remains unclear both within and particularly across latitudes.

  15. Growth responses of Picea mongolica seedlings to defoliation rate

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Adin Priadi

    2008-03-01

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

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

    DEFF Research Database (Denmark)

    Regenberg, Birgitte; Grotkjaer, Thomas; Winther, Ole

    2006-01-01

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

  18. Estimation of uncertainty for fatigue growth rate at cryogenic temperatures

    Science.gov (United States)

    Nyilas, Arman; Weiss, Klaus P.; Urbach, Elisabeth; Marcinek, Dawid J.

    2014-01-01

    Fatigue crack growth rate (FCGR) measurement data for high strength austenitic alloys at cryogenic environment suffer in general from a high degree of data scatter in particular at ΔK regime below 25 MPa√m. Using standard mathematical smoothing techniques forces ultimately a linear relationship at stage II regime (crack propagation rate versus ΔK) in a double log field called Paris law. However, the bandwidth of uncertainty relies somewhat arbitrary upon the researcher's interpretation. The present paper deals with the use of the uncertainty concept on FCGR data as given by GUM (Guidance of Uncertainty in Measurements), which since 1993 is a recommended procedure to avoid subjective estimation of error bands. Within this context, the lack of a true value addresses to evaluate the best estimate by a statistical method using the crack propagation law as a mathematical measurement model equation and identifying all input parameters. Each parameter necessary for the measurement technique was processed using the Gaussian distribution law by partial differentiation of the terms to estimate the sensitivity coefficients. The combined standard uncertainty determined for each term with its computed sensitivity coefficients finally resulted in measurement uncertainty of the FCGR test result. The described procedure of uncertainty has been applied within the framework of ITER on a recent FCGR measurement for high strength and high toughness Type 316LN material tested at 7 K using a standard ASTM proportional compact tension specimen. The determined values of Paris law constants such as C0 and the exponent m as best estimate along with the their uncertainty value may serve a realistic basis for the life expectancy of cyclic loaded members.

  19. Woodland recovery after suppression of deer: cascade effects for small mammals, wood mice (Apodemus sylvaticus and bank voles (Myodes glareolus.

    Directory of Open Access Journals (Sweden)

    Emma R Bush

    Full Text Available Over the past century, increases in both density and distribution of deer species in the Northern Hemisphere have resulted in major changes in ground flora and undergrowth vegetation of woodland habitats, and consequentially the animal communities that inhabit them. In this study, we tested whether recovery in the vegetative habitat of a woodland due to effective deer management (from a peak of 0.4-1.5 to <0.17 deer per ha had translated to the small mammal community as an example of a higher order cascade effect. We compared deer-free exclosures with neighboring open woodland using capture-mark-recapture (CMR methods to see if the significant difference in bank vole (Myodes glareolus and wood mouse (Apodemus sylvaticus numbers between these environments from 2001-2003 persisted in 2010. Using the multi-state Robust Design method in program MARK we found survival and abundance of both voles and mice to be equivalent between the open woodland and the experimental exclosures with no differences in various metrics of population structure (age structure, sex composition, reproductive activity and individual fitness (weight, although the vole population showed variation both locally and temporally. This suggests that the vegetative habitat--having passed some threshold of complexity due to lowered deer density--has allowed recovery of the small mammal community, although patch dynamics associated with vegetation complexity still remain. We conclude that the response of small mammal communities to environmental disturbance such as intense browsing pressure can be rapidly reversed once the disturbing agent has been removed and the vegetative habitat is allowed to increase in density and complexity, although we encourage caution, as a source/sink dynamic may emerge between old growth patches and the recently disturbed habitat under harsh conditions.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-01

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

  1. Variation in relative growth rate and growth traits in wild and cultivated Capsicum accessions grown under different temperatures

    NARCIS (Netherlands)

    Swart, de E.A.M.; Marcelis, L.F.M.; Voorrips, R.E.

    2006-01-01

    Differences in environmental conditions are known to influence plant growth and growth-related traits. The aim of this study was to identify the variation in relative growth rate (RGR), and its underlying physiological and morphological traits, in a group of ten wild and cultivated Capsicum accessio

  2. Physiological growth hormone replacement and rate of recurrence of craniopharyngioma: the Genentech National Cooperative Growth Study.

    Science.gov (United States)

    Smith, Timothy R; Cote, David J; Jane, John A; Laws, Edward R

    2016-10-01

    OBJECTIVE The object of this study was to establish recurrence rates in patients with craniopharyngioma postoperatively treated with recombinant human growth hormone (rhGH) as a basis for determining the risk of rhGH therapy in the development of recurrent tumor. METHODS The study included 739 pediatric patients with craniopharyngioma who were naïve to GH upon entering the Genentech National Cooperative Growth Study (NCGS) for treatment. Reoperation for tumor recurrence was documented as an adverse event. Cox proportional-hazards regression models were developed for time to recurrence, using age as the outcome and enrollment date as the predictor. Patients without recurrence were treated as censored. Multivariate logistic regression was used to examine the incidence of recurrence with adjustment for the amount of time at risk. RESULTS Fifty recurrences in these 739 surgically treated patients were recorded. The overall craniopharyngioma recurrence rate in the NCGS was 6.8%, with a median follow-up time of 4.3 years (range 0.7-6.4 years.). Age at the time of study enrollment was statistically significant according to both Cox (p = 0.0032) and logistic (p treatment era.

  3. How Much Growth Can We Expect? A Conditional Analysis of R-CBM Growth Rates by Level of Performance

    Science.gov (United States)

    Silberglitt, Benjamin; Hintze, John M.

    2007-01-01

    This study examined the reading growth rates of 7,544 students in Grades 2-6, measured over 1 year using Reading-Curriculum-Based Measurement (R-CBM) benchmark assessments administered in the fall, winter, and spring. The authors used hierarchical linear modeling to establish and compare student rates of growth within each grade level based on…

  4. Identification of subpopulations of prairie voles differentially susceptible to peer influence to decrease high alcohol intake

    Directory of Open Access Journals (Sweden)

    Allison M.J. Anacker

    2013-07-01

    Full Text Available Peer influences are critical in the decrease of alcohol (ethanol abuse and maintenance of abstinence. We previously developed an animal model of inhibitory peer influences on ethanol drinking using prairie voles and here sought to understand whether this influential behavior was due to specific changes in drinking patterns and to variation in a microsatellite sequence in the regulatory region of the vasopressin receptor 1a gene (avpr1a. Adult prairie voles’ drinking patterns were monitored in a lickometer apparatus that recorded each lick a subject exhibited during continuous access to water and 10% ethanol during periods of isolation, pair housing of high and low drinkers, and subsequent isolation. Analysis of fluid consumption confirmed previous results that high drinkers typically decrease ethanol intake when paired with low drinkers, but that a subset of voles do not decrease. Analysis of bout structure revealed differences in the number of ethanol drinking bouts in the subpopulations of high drinkers when paired with low drinkers. Lickometer drinking patterns analyzed by visual and by cross-correlation analyses demonstrated that pair housing did not increase the rate of subjects drinking in bouts occurring at the same time. The length of the avpr1a microsatellite did not predict susceptibility to peer influence or any other drinking behaviors. In summary, subpopulations of high drinkers were identified by fluid intake and number of drinking bouts, which did or did not lower their ethanol intake when paired with a low drinking peer, and these subpopulations should be explored for testing the efficacy of treatments to decrease ethanol use in groups that are likely to be responsive to different types of therapy.

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

    NARCIS (Netherlands)

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

    1993-01-01

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

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

    NARCIS (Netherlands)

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

    1993-01-01

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

  7. Establishment of superovulation procedure in Japanese field vole, Microtus montebelli.

    Science.gov (United States)

    Kageyama, Atsuko; Tanaka, Minako; Morita, Mami; Ushijima, Hitoshi; Tomogane, Hiroshi; Okada, Konosuke

    2016-08-01

    Japanese field vole (Microtus montebelli) is a wild-derived rodent and have unique characteristic. Thus, these species have been expected as model animal. This study was performed to develop novel superovulation procedure for Japanese field vole. First, when 30 IU pregnant mare's serum gonadotropin (PMSG) and 30 IU human chorionic gonadotropin (hCG) were administrated 48 hours apart, females showed higher response to hCG compared with three concentrations of PMSG. Second, to effectively induce ovulation on females after vaginal opening, they were mated with vasectomized male instead of hCG administration. Average number of ovulated oocytes using PMSG mating (13.9 ± 1.9 oocytes) was higher than PMSG-hCG (control; 6.9 ± 2.3 oocytes) or PMSG-hCG mating (6.8 ± 0.8 oocytes). Finally, we attempted superovulation using GnRH agonist (GnRHa). With this treatment, we speculated that GnRHa might induce endogenous luteinizing hormone releasing to cause ovulation. Such superovulation was performed with 30 IU PMSG and different concentration of 20% polyvinylpyrrolidone-GnRHa (15, 30, 45, and 60 μg/kg). As results, average number of ovulated oocytes was highest with 30 μg/kg GnRHa (14.5 ± 4.1 oocytes). The numbers of ovulated oocytes of other concentrations were 5.0 ± 1.4 (15 μg/kg), 12.8 ± 2.7 (45 μg/kg), and 8.8 ± 3.7 oocytes (60 μg/kg). Nuclear status of most collected oocytes was the second meiotic division (range, 94.3%-100%). These superovulation procedures will be useful for development of in vitro culture systems and assisted reproductive technologies for not only Japanese field vole but also other voles. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. How predation and landscape fragmentation affect vole population dynamics

    DEFF Research Database (Denmark)

    Dalkvist, Trine; Sibly, Richard; Topping, Christopher John

    2011-01-01

    on vole population dynamics of making predators more specialised, of altering the breeding season, and increasing the level of habitat fragmentation. We found that fragmentation as well as the presence of specialist predators are necessary for the occurrence of population cycles. Habitat fragmentation...... to unravel in field experiments. We hope our results will help understand the reasons for cycle gradients observed in other areas. Our results clearly demonstrate the importance of landscape fragmentation for population cycling and we recommend that the degree of fragmentation be more fully considered...

  9. How Predation and Landscape Fragmentation Affect Vole Population Dynamics

    DEFF Research Database (Denmark)

    Dalkvist, Trine; Sibly, Richard M.; Topping, Chris J.

    2011-01-01

    on vole population dynamics of making predators more specialised, of altering the breeding season, and increasing the level of habitat fragmentation. We found that fragmentation as well as the presence of specialist predators are necessary for the occurrence of population cycles. Habitat fragmentation...... to unravel in field experiments. We hope our results will help understand the reasons for cycle gradients observed in other areas. Our results clearly demonstrate the importance of landscape fragmentation for population cycling and we recommend that the degree of fragmentation be more fully considered...

  10. Induced Pluripotent Stem Cells of Microtus levis x Microtus arvalis Vole Hybrids: Conditions Necessary for Their Generation and Self-Renewal

    Science.gov (United States)

    Grigor’eva, E. V.; Shevchenko, A. I.; Medvedev, S. P.; Mazurok, N. A.; Zhelezova, A. I.; Zakian, S. M.

    2015-01-01

    Every year, the list of mammalian species for which cultures of pluripotent stem cells (PSCs) are generated increases. PSCs are a unique tool for extending the limits of experimental studies and modeling different biological processes. In this work, induced pluripotent stem cells (iPSCs) from the hybrids of common voles Microtus levis and Microtus arvalis, which are used as model objects to study genome organization on the molecular-genetic level and the mechanisms of X-chromosome inactivation, have been generated. Vole iPSCs were isolated and cultured in a medium containing cytokine LIF, basic fibroblast growth factor (bFGF), ascorbic acid, and fetal bovine serum. Undifferentiated state of vole iPSCs is maintained by activation of their endogenous pluripotency genes – Nanog, Oct4, Sox2, Sall4, and Esrrb. The cells were able to maintain undifferentiated state for at least 28 passages without change in their morphology and give rise to three germ layers (ectoderm, mesoderm and endoderm) upon differentiation. PMID:26798492

  11. Efficient transmission and characterization of Creutzfeldt-Jakob disease strains in bank voles.

    Directory of Open Access Journals (Sweden)

    Romolo Nonno

    2006-02-01

    Full Text Available Transmission of prions between species is limited by the "species barrier," which hampers a full characterization of human prion strains in the mouse model. We report that the efficiency of primary transmission of prions from Creutzfeldt-Jakob disease patients to a wild rodent species, the bank vole (Clethrionomys glareolus, is comparable to that reported in transgenic mice carrying human prion protein, in spite of a low prion protein-sequence homology between man and vole. Voles infected with sporadic and genetic Creutzfeldt-Jakob disease isolates show strain-specific patterns of spongiform degeneration and pathological prion protein-deposition, and accumulate protease-resistant prion protein with biochemical properties similar to the human counterpart. Adaptation of genetic Creutzfeldt-Jakob disease isolates to voles shows little or no evidence of a transmission barrier, in contrast to the striking barriers observed during transmission of mouse, hamster, and sheep prions to voles. Our results imply that in voles there is no clear relationship between the degree of homology of the prion protein of the donor and recipient species and susceptibility, consistent with the view that the prion strain gives a major contribution to the species barrier. The vole is therefore a valuable model to study human prion diversity and, being susceptible to a range of animal prions, represents a unique tool for comparing isolates from different species.

  12. Efficient transmission and characterization of creutzfeldt-jakob disease strains in bank voles.

    Directory of Open Access Journals (Sweden)

    2006-02-01

    Full Text Available Transmission of prions between species is limited by the "species barrier," which hampers a full characterization of human prion strains in the mouse model. We report that the efficiency of primary transmission of prions from Creutzfeldt-Jakob disease patients to a wild rodent species, the bank vole (Clethrionomys glareolus, is comparable to that reported in transgenic mice carrying human prion protein, in spite of a low prion protein-sequence homology between man and vole. Voles infected with sporadic and genetic Creutzfeldt-Jakob disease isolates show strain-specific patterns of spongiform degeneration and pathological prion protein-deposition, and accumulate protease-resistant prion protein with biochemical properties similar to the human counterpart. Adaptation of genetic Creutzfeldt-Jakob disease isolates to voles shows little or no evidence of a transmission barrier, in contrast to the striking barriers observed during transmission of mouse, hamster, and sheep prions to voles. Our results imply that in voles there is no clear relationship between the degree of homology of the prion protein of the donor and recipient species and susceptibility, consistent with the view that the prion strain gives a major contribution to the species barrier. The vole is therefore a valuable model to study human prion diversity and, being susceptible to a range of animal prions, represents a unique tool for comparing isolates from different species.

  13. Does the growth rate of total amount in cash salaries relate to a transition in the suicide rate?

    National Research Council Canada - National Science Library

    Inoue, Ken; Fukunaga, Tatsushige; Okazaki, Yuji

    2012-01-01

    ... annual suicide rates by vital statistics and annual growth rates of total amount in cash salary from 1995 to 2009 in Japan, and we assessed the correlation between these factors during that period using single regression analysis in an excel (Microsoft, Japanese, made in Singapore) spreadsheet. During the study period, the annual suicide rates (/10...

  14. Adoption of multivariate copulae in prognostication of economic growth by means of interest rate

    Science.gov (United States)

    Saputra, Dewi Tanasia; Indratno, Sapto Wahyu, Dr.

    2015-12-01

    Inflation, at a healthy rate, is a sign of growing economy. Nonetheless, when inflation rate grows uncontrollably, it will negatively influence economic growth. Many tackle this problem by increasing interest rate to help protecting the value of money which is detained by inflation. There are few, however, who study the effects of interest rate in economic growth. The main purposes of this paper are to find how the change of interest rate affects economic growth and to use the relationship in prognostication of economic growth. By using expenditure model, a linear relationship between economic growth and interest rate is developed. The result is then used for prediction by normal copula and Vine Archimedean copula. It is shown that increasing interest rate to tackle inflation is a poor solution. Whereas implementation of copula in predicting economic growth yields an accurate result, with not more than 0.5% difference.

  15. Estimation of the growth curve and heritability of the growth rate for giant panda (Ailuropoda melanoleuca) cubs.

    Science.gov (United States)

    Che, T D; Wang, C D; Jin, L; Wei, M; Wu, K; Zhang, Y H; Zhang, H M; Li, D S

    2015-03-27

    Giant panda cubs have a low survival rate during the newborn and early growth stages. However, the growth and developmental parameters of giant panda cubs during the early lactation stage (from birth to 6 months) are not well known. We examined the growth and development of giant panda cubs by the Chapman growth curve model and estimated the heritability of the maximum growth rate at the early lactation stage. We found that 83 giant panda cubs reached their maximum growth rate at approximately 75-120 days after birth. The body weight of cubs at 75 days was 4285.99 g. Furthermore, we estimated that the heritability of the maximum growth rate was moderate (h(2) = 0.38). Our study describes the growth and development of giant panda cubs at the early lactation stage and provides valuable growth benchmarks. We anticipate that our results will be a starting point for more detailed research on increasing the survival rate of giant panda cubs. Feeding programs for giant panda cubs need further improvement.

  16. Growth rate and resource imbalance interactively control biomass stoichiometry and elemental quotas of aquatic bacteria.

    Science.gov (United States)

    Godwin, Casey M; Whitaker, Emily A; Cotner, James B

    2017-03-01

    The effects of resource stoichiometry and growth rate on the elemental composition of biomass have been examined in a wide variety of organisms, but the interaction among these effects is often overlooked. To determine how growth rate and resource imbalance affect bacterial carbon (C): nitrogen (N): phosphorus (P) stoichiometry and elemental content, we cultured two strains of aquatic heterotrophic bacteria in chemostats at a range of dilution rates and P supply levels (C:P of 100:1 to 10,000:1). When growing below 50% of their maximum growth rate, P availability and dilution rate had strong interactive effects on biomass C:N:P, elemental quotas, cell size, respiration rate, and growth efficiency. In contrast, at faster growth rates, biomass stoichiometry was strongly homeostatic in both strains (C:N:P of 70:13:1 and 73:14:1) and elemental quotas of C, N, and P were tightly coupled (but not constant). Respiration and cell size increased with both growth rate and P limitation, and P limitation induced C accumulation and excess respiration. These results show that bacterial biomass stoichiometry is relatively constrained when all resources are abundant and growth rates are high, but at low growth rates resource imbalance is relatively more important than growth rate in controlling bacterial biomass composition. © 2016 by the Ecological Society of America.

  17. Constant growth rate can be supported by decreasing energy flux and increasing aerobic glycolysis

    NARCIS (Netherlands)

    Slavov, Nikolai; Budnik, Bogdan A; Schwab, David; Airoldi, Edoardo M; van Oudenaarden, Alexander

    2014-01-01

    Fermenting glucose in the presence of enough oxygen to support respiration, known as aerobic glycolysis, is believed to maximize growth rate. We observed increasing aerobic glycolysis during exponential growth, suggesting additional physiological roles for aerobic glycolysis. We investigated such ro

  18. Effect of Bacillus subtilis on the growth and survival rate of shrimp ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-07-20

    Jul 20, 2009 ... investigated on growth and survival rate of Litopenaeus vannamei during 60 days of culture. Sixteen aquaria with four ... the digestive enzyme activity, survival and growth of ...... Wolf Medical Publication p.186. Lt., London.

  19. Constant growth rate can be supported by decreasing energy flux and increasing aerobic glycolysis

    NARCIS (Netherlands)

    Slavov, Nikolai; Budnik, Bogdan A; Schwab, David; Airoldi, Edoardo M; van Oudenaarden, Alexander

    2014-01-01

    Fermenting glucose in the presence of enough oxygen to support respiration, known as aerobic glycolysis, is believed to maximize growth rate. We observed increasing aerobic glycolysis during exponential growth, suggesting additional physiological roles for aerobic glycolysis. We investigated such

  20. On the Rational Approximation of Analytic Functions Having Generalized Types of Rate of Growth

    Directory of Open Access Journals (Sweden)

    Devendra Kumar

    2012-01-01

    Full Text Available The present paper is concerned with the rational approximation of functions holomorphic on a domain G⊂C, having generalized types of rates of growth. Moreover, we obtain the characterization of the rate of decay of product of the best approximation errors for functions f having fast and slow rates of growth of the maximum modulus.

  1. The Renminbi Exchange Rate Reform and the Rebalancing of China’s Growth Model

    Institute of Scientific and Technical Information of China (English)

    JIANBO; SONG; SEAN; MACKINNON; SONGTAO; TAN

    2015-01-01

    This paper posits that a proper way to estimate the Renminbi(RMB) exchange rate is to base the evaluation on the Balassa-Samuelson effect, and that the optimal way to facilitate China’s growth model transformation is gradual RMB internationalization and capital account liberalization. Regression estimates show that the gross domestic product per capita growth rate, or the productivity growth rate, has strong explanatory validity when estimating the RMB exchange rate. The findings further assert that, as the growth of gross fixed capital formation slows, and the growth of household consumption speeds up, China’s economic growth will be sustained. The RMB exchange rate regime is one in which gradual reforms must yield to interest rates levels and hence should only be revalued conditionally.

  2. The Effect of Bio-Fertilizers on Plant Growth and Growth Rate of Grafted Avocado (Persea americana Mill.

    Directory of Open Access Journals (Sweden)

    Lazarus Agus Sukamto

    2014-01-01

    Full Text Available Avocado (Persea americana Mill. is considered the most nutritious of all fruits. Avocado fruit contain high unsaturated fat, protein, and energy. It could be eaten fresh for food, drinks, cooking, and cosmetics. Recently, it has become a significant commodity in international trade. Indonesia is the 2nd avocado producing country, but only little quantity of avocado fruits could be exported. The farmers usually grow avocado plants from the seeds, without proper fertilizers in their backyards or small gardens. The problems could be solved by using grafted plants, proper fertilizers, and growing in a large scale of areas. This research was conducted to find out the effect of two liquid bio-fertilizers namely Mega Rhizo and Beyonic StarTmik on the plant growth and growth rate of grafted avocado plants. Some plant growths and growth rates of grafted avocado were influenced significantly by genotype accession, kind of bio-fertilizer, and weather (temperature.  Plant growth and growth rate of most avocado accessions were not significant differences to bio-fertilizer applications, but some avocado accessions on certain months were significant differently. Growth rate ranks of plant height based on accession were no. 10, 28, 13, 1, 5, 2, and 14 consecutively. Those of canopy width were no. 28, 10, 1, 2, 14, 5, and 13 consecutively. Those of trunk diameters were no. 28, 10, 2, 5, 1, 13, and 14 consecutively. All growth rate ranks based on bio-fertilizer were Mega Rhizo, Beyonic StarTmik, and control consecutively.

  3. EFFECT OF SODIUM DODECYLBENZENESULFONIC ACID (SDBS ON THE GROWTH RATE AND MORPHOLOGY OF BORAX CRYSTAL

    Directory of Open Access Journals (Sweden)

    Suharso Suharso

    2010-06-01

    Full Text Available An investigation of the effect of sodium dodecylbenzenesulfonic acid (SDBS on both growth rate and morphology of borax crystal has been carried out.  This experiment was carried out at temperature of 25 °C and relative supersaturation of 0.21 and 0.74 under in situ cell optical microscopy method.  The result shows that SDBS inhibits the growth rate and changes the morphology of borax crystal.   Keywords: Borax; growth rate; crystallization, SDBS

  4. EFFECT OF SODIUM DODECYLBENZENESULFONIC ACID (SDBS) ON THE GROWTH RATE AND MORPHOLOGY OF BORAX CRYSTAL

    OpenAIRE

    Suharso, Suharso

    2010-01-01

    An investigation of the effect of sodium dodecylbenzenesulfonic acid (SDBS) on both growth rate and morphology of borax crystal has been carried out.  This experiment was carried out at temperature of 25 °C and relative supersaturation of 0.21 and 0.74 under in situ cell optical microscopy method.  The result shows that SDBS inhibits the growth rate and changes the morphology of borax crystal.   Keywords: Borax; growth rate; crystallization, SDBS

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

    Science.gov (United States)

    Hansen, James; Kharecha, Pushker; Sato, Makiko

    2013-03-01

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

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

    Directory of Open Access Journals (Sweden)

    Bondarenko Z. S.

    2016-02-01

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

  7. Effects of begging on growth rates of nestling chicks

    NARCIS (Netherlands)

    Rodriguez-Girones, MA; Zuniga, JM; Redondo, T

    2001-01-01

    We investigated whether an increase in begging levels delays growth of chicks. In experiment 1, we hand-reared nine pairs of ring dove squabs, divided into a control and a begging group. All squabs received similar amounts of food, but those in the begging group had to beg for a prolonged period in

  8. Effects of begging on growth rates of nestling chicks

    NARCIS (Netherlands)

    Rodriguez-Girones, MA; Zuniga, JM; Redondo, T

    2001-01-01

    We investigated whether an increase in begging levels delays growth of chicks. In experiment 1, we hand-reared nine pairs of ring dove squabs, divided into a control and a begging group. All squabs received similar amounts of food, but those in the begging group had to beg for a prolonged period in

  9. Co-infection of Borrelia afzelii and Bartonella spp. in bank voles from a suburban forest.

    Science.gov (United States)

    Buffet, Jean-Philippe; Marsot, Maud; Vaumourin, Elise; Gasqui, Patrick; Masséglia, Sébastien; Marcheteau, Elie; Huet, Dominique; Chapuis, Jean-Louis; Pisanu, Benoit; Ferquel, Elisabeth; Halos, Lénaïg; Vourc'h, Gwenaël; Vayssier-Taussat, Muriel

    2012-12-01

    We report the molecular detection of Borrelia afzelii (11%) and Bartonella spp. (56%) in 447 bank voles trapped in a suburban forest in France. Adult voles were infected by significantly more Borrelia afzelii than juveniles (pBartonella spp. between young and adult individuals (p=0.914). Six percent of the animals were co-infected by both bacteria. Analysis of the bank vole carrier status for either pathogen indicated that co-infections occur randomly (p=0.94, CI(95)=[0.53; 1.47]). Sequence analysis revealed that bank voles were infected by a single genotype of Borrelia afzelii and by 32 different Bartonella spp. genotypes, related to three known species specific to rodents (B. taylorii, B. grahamii and B. doshiae) and also two as yet unidentified Bartonella species. Our findings confirm that rodents harbor high levels of potential human pathogens; therefore, widespread surveillance should be undertaken in areas where humans may encounter rodents.

  10. Amak Island trip report - notes on the Amak song sparrow and Amak vole

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Both the Amak Island song sparrow (Melospiza melodia amaka) and Amak vole (Microtus oeconomus amakensis) are currently category 2 candidate species under the...

  11. Landscape structure mediates the effects of a stressor on field vole populations

    DEFF Research Database (Denmark)

    Dalkvist, Trine; Sibly, Richard M.; Topping, Christopher John

    2013-01-01

    Spatio-temporal landscape heterogeneity has rarely been considered in population-level impact assessments. Here we test whether landscape heterogeneity is important by examining the case of a pesticide applied seasonally to orchards which may affect non-target vole populations, using a validated...... ecologically realistic and spatially explicit agent-based model. Voles thrive in unmanaged grasslands and untreated orchards but are particularly exposed to applied pesticide treatments during dispersal between optimal habitats. We therefore hypothesised that vole populations do better (1) in landscapes...... containing more grassland and (2) where areas of grassland are closer to orchards, but (3) do worse if larger areas of orchards are treated with pesticide. To test these hyposeses we made appropriate manipulations to a model landscape occupied by field voles. Pesticide application reduced model population...

  12. Experimental Infection of voles with Francisella tularensis indicates their amplification role in tularemia outbreaks.

    Directory of Open Access Journals (Sweden)

    Heidi Rossow

    Full Text Available Tularemia outbreaks in humans have been linked to fluctuations in rodent population density, but the mode of bacterial maintenance in nature is unclear. Here we report on an experiment to investigate the pathogenesis of Francisella tularensis infection in wild rodents, and thereby assess their potential to spread the bacterium. We infected 20 field voles (Microtus agrestis and 12 bank voles (Myodes glareolus with a strain of F. tularensis ssp. holarctica isolated from a human patient. Upon euthanasia or death, voles were necropsied and specimens collected for histological assessment and identification of bacteria by immunohistology and PCR. Bacterial excretion and a rapid lethal clinical course with pathological changes consistent with bacteremia and tissue necrosis were observed in infected animals. The results support a role for voles as an amplification host of F. tularensis, as excreta and, in particular, carcasses with high bacterial burden could serve as a source for environmental contamination.

  13. Frequency dependence of fatigue and corrosion fatigue crack growth rate

    Energy Technology Data Exchange (ETDEWEB)

    Marvasti, Mohammad Hassan; Chen, Weixing [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB (Canada); Kania, Richard; Worthingham, Robert [TransCanada Pipelines Limited, Calgary, AB (Canada); Van Boven, Gregory [Spectra Energy Transmission Limited, Vancouver, BC (Canada)

    2010-07-01

    It was in the mid-1980s that stress corrosion cracking (SCC) was first found in near-neutral pH conditions on the TransCanada pipeline system. Since then, there have been many reports of pipeline cracking in Canada in these conditions. The huge quantity of pipelines in Canada and the number of failures have brought great interest in investigation of this cracking. A study was conducted on one X52 pipeline steel. It used compact tension specimens for corrosion fatigue and fatigue tests in air. The following conclusions were drawn: 1) crack growth in near-neutral pH conditions can be explained by a factor, which reflects the combined action of the mechanical driving force and the hydrogen effects; 2) mechanical dormancy can be common when oil and gas pipelines are in operation; 3) hydrogen is a determining factor of crack growth when pipeline steels are exposed to near-neutral pH conditions.

  14. Biological mechanisms discriminating growth rate and adult body weight phenotypes in two Chinese indigenous chicken breeds

    NARCIS (Netherlands)

    Dou, Tengfei; Zhao, Sumei; Rong, Hua; Gu, Dahai; Li, Qihua; Huang, Ying; Xu, Zhiqiang; Chu, Xiaohui; Tao, Linli; Liu, Lixian; Ge, Changrong; Pas, te Marinus F.W.; Jia, Junjing

    2017-01-01

    Background: Intensive selection has resulted in increased growth rates and muscularity in broiler chickens, in addition to adverse effects, including delayed organ development, sudden death syndrome, and altered metabolic rates. The biological mechanisms underlying selection responses remain

  15. Solar effect on the Rayleigh-Taylor instability growth rate as simulated by the NCAR TIEGCM

    Science.gov (United States)

    Wu, Qian

    2017-04-01

    The TIEGCM (Thermosphere Ionosphere Electrodynamics General Circulation Model) is used to investigate the solar effect on the equatorial ionospheric Rayleigh-Taylor (R-T) instability growth rate, which is responsible for the occurrence of the plasma bubbles. The R-T growth rate is calculated for the solar maximum year 2003 and minimum 2009. The growth rate is strongly dependent on the solar activity. During solar maximum, the pre-reversal enhancement is much stronger leading to higher R-T growth rate. The R-T growth rates from the TIEGCM follow the same solar dependence as the observed occurrence of equatorial plasma bubbles by DMSP satellites. The R-T growth rate also enhances when the day/night terminator is parallel to the magnetic field line near the equator. The R-T growth rate does not correlate well with the solar F10.7 index on a short time scale ( 10 days) because the field-line integrated electron content gradient cancels out the positive correlation between the vertical ion drift with the F10.7 index. The TIEGCM result shows the importance of the electron content gradient to the R-T growth rate and the plasma bubble occurrence. The bubble occurrence rates were estimated based on the vertical ion drift simulation results.

  16. Geometric analysis and estimation of the growth rate gradient on gastropod shells.

    Science.gov (United States)

    Noshita, Koji; Shimizu, Keisuke; Sasaki, Takenori

    2016-01-21

    The morphology of gastropod shells provides a record of the growth rate at the aperture of the shell, and molecular biological studies have shown that the growth rate gradient along the aperture of a gastropod shell can be closely related to gene expression at the aperture. Here, we develop a novel method for deriving microscopic growth rates from the macroscopic shapes of gastropod shells. The growth vector map of a shell provides information on the growth rate gradient as a vector field along the aperture, over the growth history. However, it is difficult to estimate the growth vector map directly from the macroscopic shape of a specimen, because the degree of freedom of the growth vector map is very high. In order to overcome this difficulty, we develop a method of estimating the growth vector map based on a growing tube model, where the latter includes fewer parameters to be estimated. In addition, we calculate an aperture map specifying the magnitude of the growth vector at each location, which can be compared with the expression levels of several genes or proteins that are important in morphogenesis. Finally, we show a concrete example of how macroscopic shell shapes evolve in a morphospace when microscopic growth rate gradient changes.

  17. Revisiting the “visible burrow system”: The impact of the group, social rank, and gender on voles under owl attack.

    Science.gov (United States)

    Bodek, Sivan; Eilam, David

    2015-07-01

    In the present study, corticosterone levels and behavior were compared between voles (Microtus socialis) that were attacked by a barn owl (Tyto alba) and voles that did not experience such attack. Both female and male voles were exposed to the owl either together with their group mates or when socially isolated. As hypothesized, corticosterone levels were higher in voles after the owl attack, and were higher in females than in males. However, blood corticosterone was higher in voles that experienced the attack in groups compared with the socially-isolated voles. The latter result seems enigmatic, since group members usually benefit from the “social buffering” conferred by their group-mates. It is suggested that contagious vigilance among group members accounts for the higher mean corticosterone level in grouped compared to socially-isolated voles, overshadowing the possible impact of social buffering. We also found a negative correlation between body mass and corticosterone level, with more high-mass voles showing low corticosterone levels compared with low mass voles. This finding accords with a previous study in which the behavior of high-mass voles was less affected by owl attack compared to low-mass voles. The novelty of the present results therefore lies in supporting, at the hormonal level, past behavioral findings in rats and voles, and in demonstrating that high-mass voles, by virtue of their physical strength and perhaps also their life experience, are less stressed by the owl attack and become the leaders and stabilizers of their groups.

  18. Prairie voles as a novel model of socially facilitated excessive drinking.

    Science.gov (United States)

    Anacker, Allison M J; Loftis, Jennifer M; Kaur, Simranjit; Ryabinin, Andrey E

    2011-01-01

    Social relationships strongly affect alcohol drinking in humans. Traditional laboratory rodents do not exhibit social affiliations with specific peers, and cannot adequately model how such relationships impact drinking. The prairie vole is a socially monogamous rodent used to study social bonds. The present study tested the prairie vole as a potential model for the effects of social affiliations on alcohol drinking. Same-sex adult sibling prairie voles were paired for five days, and then either separated into individual cages, or housed in pairs. Starting at the time of separation, the voles received unlimited access to alcohol in a two-bottle choice test versus water. Pair-housed siblings exhibited higher preference for alcohol, but not saccharin, than singly housed voles. There was a significant correlation between the amount of alcohol consumed by each member of a pair when they were housed together (r = 0.79), but not when housed apart (r = 0.20). Following automated analysis of circadian patterns of fluid consumption indicating peak fluid intake before and after the dark phase, a limited access two-hour two-bottle choice procedure was established. Drinking in this procedure resulted in physiologically relevant blood ethanol concentrations and increased Fos immunoreactivity in perioculomotor urocortin containing neurons (but not in nucleus accumbens or central nucleus of the amygdala). The high ethanol preference and sensitivity to social manipulation indicate that prairie voles can serve to model social influences on excessive drinking.

  19. BAC-based sequencing of behaviorally-relevant genes in the prairie vole.

    Directory of Open Access Journals (Sweden)

    Lisa A McGraw

    Full Text Available The prairie vole (Microtus ochrogaster is an important model organism for the study of social behavior, yet our ability to correlate genes and behavior in this species has been limited due to a lack of genetic and genomic resources. Here we report the BAC-based targeted sequencing of behaviorally-relevant genes and flanking regions in the prairie vole. A total of 6.4 Mb of non-redundant or haplotype-specific sequence assemblies were generated that span the partial or complete sequence of 21 behaviorally-relevant genes as well as an additional 55 flanking genes. Estimates of nucleotide diversity from 13 loci based on alignments of 1.7 Mb of haplotype-specific assemblies revealed an average pair-wise heterozygosity (8.4×10(-3. Comparative analyses of the prairie vole proteins encoded by the behaviorally-relevant genes identified >100 substitutions specific to the prairie vole lineage. Finally, our sequencing data indicate that a duplication of the prairie vole AVPR1A locus likely originated from a recent segmental duplication spanning a minimum of 105 kb. In summary, the results of our study provide the genomic resources necessary for the molecular and genetic characterization of a high-priority set of candidate genes for regulating social behavior in the prairie vole.

  20. Who are the bosses? Group influence on the behavior of voles following owl attack.

    Science.gov (United States)

    Kleiman, Michal; Bodek, Sivan; Eilam, David

    2014-10-01

    Individual members of a group must conform to the group norms, as they may otherwise become isolated from the group or the group may split. On the other hand, social groups usually comprise various social ranks and display a differential division of labor and consequently different behaviors. The present study was aimed at examining how the above factors are manifested in social voles that had experienced owl attack. Here, we reconfirm the findings of past studies: that grouped voles converge to display similar behavior after owl attack. In addition, we found that high-mass voles were more active in the open sectors of the experimental set-ups both before and after the owl attack, whereas low-mass voles dichotomized to those that increased and those that decreased their activity in the open following owl attack. Taking body mass as a proxy for social rank, it is suggested that as a consequence of their larger size and of their experience and physical strength, high-mass voles both presented an exemplary model for the low-mass voles and, accordingly, assumed leadership and stabilized their group's behavior. We also suggest a hypothetical model for the propagation of behavior in hierarchical groups.

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

    Directory of Open Access Journals (Sweden)

    Hamid Reza Vakili Fard

    2014-09-01

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

  2. Dividend growth, cash flow, and discount rate news

    OpenAIRE

    Garrett, Ian; Priestley, Richard

    2012-01-01

    Using a new variable based on a model of dividend smoothing, we find that dividend growth is highly predictable and that cash flow news contributes importantly to return variability. Cash flow betas derived from this predictability are central to explaining the size effect in the cross section of returns. However, they do not explain the value effect; this is explained by noise betas. We also find that the relative importance of cash flow news in explaining recent stock price run-ups and subs...

  3. Dividend growth, cash flow, and discount rate news

    OpenAIRE

    Garrett, Ian; Priestley, Richard

    2012-01-01

    Using a new variable based on a model of dividend smoothing, we find that dividend growth is highly predictable and that cash flow news contributes importantly to return variability. Cash flow betas derived from this predictability are central to explaining the size effect in the cross section of returns. However, they do not explain the value effect; this is explained by noise betas. We also find that the relative importance of cash flow news in explaining recent stock price run-ups and subs...

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

    Directory of Open Access Journals (Sweden)

    Nicolae Ghiba

    2010-12-01

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

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

    DEFF Research Database (Denmark)

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

    2008-01-01

    Background: Characterization of cellular growth is central to understanding living systems. Here, we applied a three-factor design to study the relationship between specific growth rate and genome-wide gene expression in 36 steady-state chemostat cultures of Saccharomyces cerevisiae. The three...... factors we considered were specific growth rate, nutrient limitation, and oxygen availability. Results: We identified 268 growth rate dependent genes, independent of nutrient limitation and oxygen availability. The transcriptional response was used to identify key areas in metabolism around which m...... transcription factor target sets, transcription factors that coordinate balanced growth were also identified. Our analysis shows that FhII, Rap1, and Sfp1, regulating protein biosynthesis, have significantly enriched target sets for genes up-regulated with increasing growth rate. Cell cycle regulators...

  6. Dependence of Growing High-Quality Gem Diamonds on Growth Rates by Temperature Gradient Method

    Institute of Scientific and Technical Information of China (English)

    ZANG Chuan-Yi; JIA Xiao-Peng; REN Guo-Zhong; WANG Xian-Cheng

    2004-01-01

    @@ Using the temperature gradient method under high pressure and high temperature, we investigate the dependence of growing high-quality gem diamond crystals on the growth rates. It is found that the lower the growth rate of gem diamond crystals, the larger the temperature range of growing high-quality gem diamond crystals, and the easier the control of temperature.

  7. Influence of growth rate and starvation on fluorescent in situ hybridization of Rhodopseudomonas palustris

    NARCIS (Netherlands)

    Oda, Y; Slagman, SJ; Meijer, WG; Forney, LJ; Gottschal, JC

    In situ hybridization with a fluorescently labeled 16S rRNA-targeted probe was examined using Rhodopseudomonas palustris as a model organism, which had been grown at different rates and under different conditions of growth and starvation. The specific growth rate did not affect the percentage of

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

    Institute of Scientific and Technical Information of China (English)

    Yan Ke-zhu; Tan Wei-han

    2000-01-01

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

  9. Climate is a stronger driver of tree and forest growth rates than soil and disturbance

    NARCIS (Netherlands)

    Toledo, M.; Poorter, L.; Peña-Claros, M.; Alarcón, A.; Balcázar, J.; Leaño, C.; Licona, J.C.; Llanque, O.; Vroomans, V.; Zuidema, P.; Bongers, F.

    2011-01-01

    1. Essential resources such as water, nutrients and light vary over space and time and plant growth rates are expected to vary accordingly. We examined the effects of climate, soil and logging disturbances on diameter growth rates at the tree and stand level, using 165 1-ha permanent sample plots di

  10. Relative growth rate variation of evergreen and deciduous savanna tree species is driven by different traits

    NARCIS (Netherlands)

    Tomlinson, K.W.; Poorter, L.; Bongers, F.; Borghetti, F.; Jacobs, L.; Langevelde, van F.

    2014-01-01

    Background and Aims Plant relative growth rate (RGR) depends on biomass allocation to leaves (leaf mass fraction, LMF), efficient construction of leaf surface area (specific leaf area, SLA) and biomass growth per unit leaf area (net assimilation rate, NAR). Functional groups of species may differ in

  11. Halophilic (aerobic) bacterial growth rate of mangrove ecosystem.

    Science.gov (United States)

    Khan, A Saleem; Ali, M Sheik; Baig, I Juned Ahmed

    2009-09-01

    Mangroves are woody specialized trees of tropics and are valuable flora contributing to economical, ecological, scientific and cultural resources. They thrive in salty environments like coastal regions and are aid towards disaster management facing the onslaught of giant waves such as Tsunami. Analysis of mangrove soil on the banks of the Adyar river behind the Theosophical society campus, Adyar, Chennai, India, gave a startling revelation of microorganisms that can tolerate different salinity ranges. Previous studies in Pichavaram delta, have reported bacterial isolates such as nitrogen fixing bacteria, halophiles and several others. However their efficiency in the growth of mangrove forest has been studied to a lesser extent. The present study has been designed and formulated to estimate halophilic (aerobic) bacterial load from mangroves soil sample based on depth and salinity of the soil and further the efficiency if any of these isolates in the growth of mangroves. Results have been correlated and a cohesive conclusion reached for further intensive research. This study throws light on the ecology of the bacterial population in the coastal marine environment inhabited bymangroves and its possible role in disaster mitigation.

  12. Optimum growth rate of Belgian Blue double-muscled replacement ...

    African Journals Online (AJOL)

    Leo Fiems

    A higher rate of gain from zero to four months did not affect subsequent heifer BWG. There was ... especially when this period coincided with the grazing season. This may ... All cows, except those with BWBC >650 kg, lost weight, and BW loss.

  13. Wavy membranes and the growth rate of a planar chemical garden: Enhanced diffusion and bioenergetics

    OpenAIRE

    Ding, Yang; Batista, Bruno; Steinbock, Oliver; Cartwright, Julyan H. E.; Cardoso, Silvana S. S.

    2016-01-01

    In order to model ion transport across protocell membranes in Hadean hydrothermal vents, we consider both theoretically and experimentally the planar growth of a precipitate membrane formed at the interface between two parallel fluid streams in a two-dimensional microfluidic reactor. The growth rate of the precipitate is found to be proportional to the square root of time, which is characteristic of diffusive transport. However, the dependence of the growth rate on the concentrations of hydro...

  14. What's New and What's Old in New Growth Theory: Endogenous Technology, Microfoundation, and Growth Rate Predictions

    OpenAIRE

    Schneider, Johannes; Ziesemer, Thomas

    1994-01-01

    This paper surveys new growth theory with emphasis on three open issues known from old endogenous growth theory of the sixties: i) What is the content of the black-box variable 'technology'? ii) Which market structure prevails when endogenous technology generates dynamically increasing returns to scale? iii) What are the justifications for and implications of different specifications of production functions for technical progress? We show that new growth theory has made progress on the first ...

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

    DEFF Research Database (Denmark)

    Lone, Agertoft; Søren, Pedersen

    2009-01-01

    ) and the ICS fluticasone propionate (FP) on lower-leg growth rate and hypothalamic-pituitary-adrenal-axis function in children with mild asthma. In a double-blind, placebo-controlled, three-period crossover study, 28 children, aged 6-12 yr, sequentially received daily doses of CIC 320 mug, FP 375 mug (330 mug....... No statistically significant differences were seen in lower-leg growth rates between CIC (0.30 mm/wk) and placebo (0.43 mm/wk) treatments. Lower-leg growth rate during FP treatment (0.08 mm/wk) was significantly reduced compared with both placebo [least squares (LS) mean: -0.35 (95% CI: -0.53, -0.18; p = 0...... no significant effect on lower-leg growth rate in children aged 6-12 yr with mild asthma. In contrast, a similar dose of FP significantly reduced lower-leg growth rate compared with placebo and CIC....

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

    CERN Document Server

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

    2006-01-01

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

  17. The effect of density gradient on the growth rate of relativistic Weibel instability

    Energy Technology Data Exchange (ETDEWEB)

    Mahdavi, M., E-mail: m.mahdavi@umz.ac.ir [Physics Department, University of Mazandaran, P.O. Box 47415-416, Babolsar (Iran, Islamic Republic of); Khodadadi Azadboni, F., E-mail: f.khodadadi@stu.umz.ac.ir [Physics Department, University of Mazandaran, P.O. Box 47415-416, Babolsar (Iran, Islamic Republic of); Young Researchers Club, Sari Branch, Islamic Azad University, P.O. Box 48161-194, Sari (Iran, Islamic Republic of)

    2014-02-15

    In this paper, the effect of density gradient on the Weibel instability growth rate is investigated. The density perturbations in the near corona fuel, where temperature anisotropy, η, is larger than the critical temperature anisotropy, η{sub c}, (η > η{sub c}), enhances the growth rate of Weibel instability due to the sidebands coupled with the electron oscillatory velocity. But for η < η{sub c}, the thermal spread of the energetic electrons reduces the growth rate. Also, the growth rate can be reduced if the relativistic parameter (Lorentz factor) is sufficiently large, γ > 2. The analysis shows that relativistic effects and density gradient tend to stabilize the Weibel instability. The growth rate can be reduced by 88% by reducing η by a factor of 100 and increasing relativistic parameter by a factor of 3.

  18. Two-Way Selection for Growth Rate in the Common Carp (CYPRINUS CARPIO L.)

    Science.gov (United States)

    Moav, R.; Wohlfarth, G.

    1976-01-01

    The domesticated European carp was subjected to a two-way selection for growth rate. Five generations of mass selection for faster growth rate did not yield any response, but subsequent selection between groups (families) resulted in considerable progress while maintaining a large genetic variance. Selection for slow growth rate yielded relatively strong response for the first three generations. Random-bred control lines suffered from strong inbreeding depression and when two lines were crossed, the F1 showed a high degree of heterosis. Selection was performed on pond-raised fish, but growth rate was also tested in cages. A strong pond-cage genetic interaction was found. A theoretical explanation was suggested involving overdominance for fast growth rate and amplification through competition of intra-group but not inter-group variation. PMID:1248737

  19. Causes of variation in growth rate of reindeer calves

    Directory of Open Access Journals (Sweden)

    C. J. Petersson

    1993-12-01

    Full Text Available Weights of individual reindeer calves were registered on 3 or 4 occasions from the July roundup to the last slaughter roundup in January during each of four consecutive years (1986 to 1989. The observations were made in a tagged herd located in the southern part of the reindeer area in Sweden (63°N, 12°E. A total of 10 400 live-weight measurements were made, and the relationship between pre-slaughter weight and carcass weight was estimated using data from 109 individuals. Variation in weight and weight gain between weighing occasions was related to sex, number of days in the corral, scale and year. Non-linear growth curves were fit to the adjusted weights. For each sex, smoothed average weights and dispersions, both within and between year, as well as the coefficient of variation were calculated from data generated from the estimated functions. Individual calf weights were shown to be influenced by sex, weighing day within occasion, and by year. Reindeer calves gained between 20 and 25 kg in live body weight from two to 6-8 months of age. Male calves were heavier than female calves over the whole period and they gained in live weight on average 10 g/day more than female calves. Between year coefficient of variation was between 1.5 and 7% with the largest variation between years for July and January weights and the lowest variation for September weights. The growth curves showed that the major increase in weight was between July and September. From September to December/January the additional increase was only 5%. Dressing-percentage was influenced by live weight prior to slaughter. A positive relationship between live weight and dressing percentage was shown.

  20. Rate limits in silicon sheet growth - The connections between vertical and horizontal methods

    Science.gov (United States)

    Thomas, Paul D.; Brown, Robert A.

    1987-01-01

    Meniscus-defined techniques for the growth of thin silicon sheets fall into two categories: vertical and horizontal growth. The interactions of the temperature field and the crystal shape are analyzed for both methods using two-dimensional finite-element models which include heat transfer and capillarity. Heat transfer in vertical growth systems is dominated by conduction in the melt and the crystal, with almost flat melt/crystal interfaces that are perpendicular to the direction of growth. The high axial temperature gradients characteristic of vertical growth lead to high thermal stresses. The maximum growth rate is also limited by capillarity which can restrict the conduction of heat from the melt into the crystal. In horizontal growth the melt/crystal interface stretches across the surface of the melt pool many times the crystal thickness, and low growth rates are achievable with careful temperature control. With a moderate axial temperature gradient in the sheet a substantial portion of the latent heat conducts along the sheet and the surface of the melt pool becomes supercooled, leading to dendritic growth. The thermal supercooling is surpressed by lowering the axial gradient in the crystal; this configuration is the most desirable for the growth of high quality crystals. An expression derived from scaling analysis relating the growth rate and the crucible temperature is shown to be reliable for horizontal growth.

  1. Growth rates of atmospheric molecular clusters determined from cluster appearance times and collision-evaporation fluxes

    Science.gov (United States)

    Kontkanen, Jenni; Olenius, Tinja; Lehtipalo, Katrianne; Vehkamäki, Hanna; Kulmala, Markku

    2015-04-01

    The probability of freshly formed particles to survive to climatically relevant sizes is determined by the competition between the coagulation loss rate and the particle growth rate. Therefore, various methods have been developed to deduce the growth rates from measured particle size distributions. Recently, the growth rates of sub-3nm clusters have been determined based on the appearance times of different cluster sizes. However, it is not clear to what extent these growth rates are consistent with the growth rates corresponding to molecular fluxes between clusters. In this work, we simulated the time evolution of a population of sub-3 nm molecular clusters and compared the growth rates determined (1) from the cluster appearance times and (2) from the collision-evaporation fluxes between different cluster sizes. We performed a number of simulations by varying the ambient conditions and the properties of the model substance. In the first simulation set, the Gibbs free energy of the formation of the clusters was assumed to have a single maximum and no minima, corresponding to a monotonically increasing stability as a function of cluster size. The saturation vapor pressure was selected so that the growth proceeded solely via monomer additions. The growth rates were determined separately for each cluster. However, to see the effect of finite size resolution, we also performed simulations where the clusters were grouped into size bins, for which we determined the growth rates. In the second simulation set, the saturation vapor pressure was lowered so that the collisions of small clusters significantly contributed to the growth. As the growth rate of a single cluster is ambiguous in this case, the growth rates were determined only for different size bins. We performed simulations using a similar free energy profile as in other simulations but we also used a free energy profile containing a local minimum, corresponding to small stable clusters. Our simulations show that

  2. Soil removed by voles of the genus Pitymys in the Spanish Pyrenees

    Directory of Open Access Journals (Sweden)

    Borghi, C. E.

    1990-12-01

    Full Text Available The erosiogenic activity of Pyrenean mountain voles is studied following the measures taken in an experimental plot in the Western Pyrenees. An easy model for estimating the volume and weight of soil carried to the surface by voles is presented and used to quantify this amount in natural conditions. Fossorial Pyrenean rodents seem to dislodge well over 6Tm/ha.yr of soil on the colonized areas above the timberline. The four stages (new, recent, old, and vegetated of the evolution of soil heaps are discussed. Finally, an attempt is made to evaluate the rate of horizontal sediment transport due to the direct action of voles, with a maximum result of 17 cm3/cm.yr, quite comparable to pure geoclimatic rates.

    [es] Se estudia la actividad de movimiento del suelo de los roedores pirenaicos del género Pitymys, a partir de los datos obtenidos en una parcela experimental situada en los Pirineos Occidentales. Se presenta un modelo sencillo para estimar la cantidad de tierra removida a partir de medidas que pueden tomarse fácilmente en el campo, y se emplea dicho modelo para evaluar esta magnitud en condiciones naturales. Al parecer, los roedores subterráneos pueden sacar al exterior más de 6 Tm de tierra por hectárea y año en las zonas epiforestales que colonizan. También se discute la evolución del suelo removido y sus condiciones para la erosión por escorrentía. Finalmente se intenta evaluar la tasa de transporte horizontal del sedimento debida a los animales, que resulta ser de hasta 17 cm3 por cm y año, un valor claramente comparable con los debidos a agentes geoclimáticos.
    [fr] On a étudié l'activité fouisseuse des campagnols pyrénéens du genre Pitymys, d'après les données recueillies dans une enclosure expérimentale située dans les Pyrénées de l'Ouest. On présente un modèle simple permettant d'estimer la quantité de sol mue par les campagnols a partir de mésurements qu

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

    Directory of Open Access Journals (Sweden)

    Valerija Botrić

    2016-06-01

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

  4. Growth-Phase Sterigmatocystin Formation on Lactose Is Mediated via Low Specific Growth Rates in Aspergillus nidulans

    Directory of Open Access Journals (Sweden)

    Zoltán Németh

    2016-11-01

    Full Text Available Seed contamination with polyketide mycotoxins such as sterigmatocystin (ST produced by Aspergilli is a worldwide issue. The ST biosynthetic pathway is well-characterized in A. nidulans, but regulatory aspects related to the carbon source are still enigmatic. This is particularly true for lactose, inasmuch as some ST production mutant strains still synthesize ST on lactose but not on other carbon substrates. Here, kinetic data revealed that on d-glucose, ST forms only after the sugar is depleted from the medium, while on lactose, ST appears when most of the carbon source is still available. Biomass-specified ST production on lactose was significantly higher than on d-glucose, suggesting that ST formation may either be mediated by a carbon catabolite regulatory mechanism, or induced by low specific growth rates attainable on lactose. These hypotheses were tested by d-glucose limited chemostat-type continuous fermentations. No ST formed at a high growth rate, while a low growth rate led to the formation of 0.4 mg·L−1 ST. Similar results were obtained with a CreA mutant strain. We concluded that low specific growth rates may be the primary cause of mid-growth ST formation on lactose in A. nidulans, and that carbon utilization rates likely play a general regulatory role during biosynthesis.

  5. Growth rates and energy intake of hand-reared cheetah cubs (Acinonyx jubatus) in South Africa.

    Science.gov (United States)

    Bell, K M; Rutherfurd, S M; Morton, R H

    2012-04-01

    Growth rate is an important factor in neonatal survival. The aim of this study was to determine growth rates in hand-reared cheetah cubs in South Africa fed a prescribed energy intake, calculated for growth in the domestic cat. Growth was then compared with previously published data from hand-reared cubs in North America and the relationship between growth and energy intake explored. Daily body weight (BW) gain, feed and energy intake data was collected from 18 hand-reared cheetah cubs up to 120 days of age. The average pre-weaning growth rate was 32 g/day, which is lower than reported in mother-reared cubs and hand-reared cubs in North American facilities. However, post-weaning growth increased to an average of 55 g/day. Growth was approximately linear prior to weaning, but over the entire age range it exhibited a sigmoidal shape with an asymptotic plateau averaging 57 kg. Energy intake associated with pre-weaning growth was 481 kJ ME/kg BW(0.75). Regression analysis described the relationship between metabolic BW, metabolisable energy (ME) intake, and hence daily weight gain. This relationship may be useful in predicting energy intake required to achieve growth rates in hand-reared cheetah cubs similar to those observed for their mother-reared counterparts. © 2011 Blackwell Verlag GmbH.

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

    Institute of Scientific and Technical Information of China (English)

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

    2001-01-01

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

  7. Temperature responses of substrate carbon conversion efficiencies and growth rates of plant tissues.

    Science.gov (United States)

    Hansen, Lee D; Thomas, Nathan R; Arnholdt-Schmitt, Birgit

    2009-12-01

    Growth rates of plant tissues depend on both the respiration rate and the efficiency with which carbon is incorporated into new structural biomass. Calorespirometric measurement of respiratory heat and CO2 rates, from which both efficiency and growth rate can be calculated, is a well established method for determining the effects of rapid temperature changes on the respiratory and growth properties of plant tissues. The effect of the alternative oxidase/cytochrome oxidase activity ratio on efficiency is calculated from first principles. Data on the temperature dependence of the substrate carbon conversion efficiency are tabulated. These data show that epsilon is maximum and approximately constant through the optimum growth temperature range and decreases rapidly as temperatures approach temperature limits to growth. The width of the maximum and the slopes of decreasing epsilon at high and low temperatures vary greatly with species, cultivars and accessions.

  8. Growth rate hypothesis and efficiency of protein synthesis under different sulphate concentrations in two green algae.

    Science.gov (United States)

    Giordano, Mario; Palmucci, Matteo; Raven, John A

    2015-11-01

    The growth rate hypothesis (GRH) predicts a positive correlation between growth rate and RNA content because growth depends upon the protein synthesis machinery. The application of this hypothesis to photoautotrophic organisms has been questioned. We tested the GRH on one prasinophycean, Tetraselmis suecica, and one chlorophycean, Dunaliella salina, grown at three sulphate concentrations. Sulphate was chosen because its concentration in the oceans increased through geological time and apparently had a role in the evolutionary trajectories of phytoplankton. Cell protein content and P quota were positively related to the RNA content (r = 0.62 and r = 0.74, respectively). The correlation of the RNA content with growth rates (r = 0.95) indicates that the GRH was valid for these species when growth rates were below 0.82 d(-1) .

  9. About supersaturation and growth rates of hydrargillite Al(OH) 3 in alumina caustic solutions

    Science.gov (United States)

    Veesler, Stéphane; Boistelle, Roland

    1993-06-01

    Growth rates of hydrargillite crystals, Al(OH) 3, growing from concentrated caustic solutions, are traditionally plotted and discussed as a function of the difference between actual concentration and solubility of alumina. This way to express supersaturation is probably due to practical or technical reasons, as hydrargillite is mainly grown in industrial plants. However, as the solubility of hydrargillite is greatly affected by the presence of caustic soda there are as many growth rate curves as there are solutions at different soda concentrations, if supersaturation is expressed as a concentration difference. In the present paper we show that all growth rates, measured in different caustic solutions, lie on a single curve if supersaturation is normalized with respect to solubility, i.e. expressed as a ratio of actual concentration over solubility. Accordingly, growth rates become independent of the caustic concentrations when growth takes place at the same supersaturation.

  10. ppGpp is the major source of growth rate control in E. coli.

    Science.gov (United States)

    Potrykus, Katarzyna; Murphy, Helen; Philippe, Nadège; Cashel, Michael

    2011-03-01

    It is widely accepted that the DNA, RNA and protein content of Enterobacteriaceae is regulated as a function of exponential growth rates; macromolecular content increases with faster growth regardless of specific composition of the growth medium. This phenomenon, called growth rate control, primarily involves regulation of ribosomal RNA and ribosomal protein synthesis. However, it was uncertain whether the global regulator ppGpp is the major determinant for growth rate control. Therefore, here we re-evaluate the effect of ppGpp on macromolecular content for different balanced growth rates in defined media. We find that when ppGpp is absent, RNA/protein and RNA/DNA ratios are equivalent in fast and slow growing cells. Moreover, slow growing ppGpp-deficient cells with increased RNA content, display a normal ribosomal subunit composition although polysome content is reduced when compared with fast growing wild-type cells. From this we conclude that growth rate control does not occur in the absence of ppGpp. Also, artificial elevation of ppGpp or introduction of stringent RNA polymerase mutants in ppGpp-deficient cells restores this control. We believe these findings strongly argue in favour of ppGpp and against redundant regulation of growth rate control by other factors in Escherichia coli and other enteric bacteria.

  11. Magnesite growth rates as a function of temperature and saturation state

    Science.gov (United States)

    Saldi, Giuseppe D.; Jordan, Guntram; Schott, Jacques; Oelkers, Eric H.

    2009-10-01

    Magnesite growth rates and step velocities have been measured systematically as a function of temperature from 80 to 105 °C and saturation state in 0.1 M NaCl solutions using hydrothermal atomic force microscopy (HAFM). The observations indicate that at these conditions magnesite precipitation is dominated by the coupling of step generation via spiral growth at screw dislocations and step advancement away from these dislocations. As these two processes occur in series the slowest of these dominates precipitation rates. At 100 °C magnesite growth rates ( r) determined by HAFM are consistent with r=k(Ω-1)2, where k is a constant equal to 6.5 × 10 -16 mol/cm 2/s and Ω is the saturation index with respect to magnesite. This equation is consistent with spiral growth step generation controlling magnesite precipitation rates. Corresponding magnesite precipitation rates measured using mixed-flow reactors are shown to be consistent with both the rates measured by HAFM and the spiral growth theory, confirming the rate limiting mechanism. Step advancement, however, is observed to slow far faster than step generation with decreasing temperature; the activation energy for step advancement is 159 kJ/mol whereas step generation rates have an estimated activation energy of ˜60 kJ/mol. As such, it seems likely that at ambient temperatures magnesite growth is limited by very slow step advancement rates.

  12. Growth pattern and carcase development in male ducks selected for growth rate.

    Science.gov (United States)

    Maruyama, K; Akbar, M K; Turk, C M

    1999-05-01

    1. Growth patterns of the whole body, eviscerated carcases, breast muscle, leg and thigh muscles and abdominal fat pads were compared in 4 lines (Lines A, B, C, and D) of male ducks selected for market weight (n = 1305) using growth curve analysis, allometric growth analysis and repeated measure analysis. At 49 d of age, Line A was heaviest, followed by Line B, Line C and Line D. 2. Ducks were fed ad libitum under 24-h lighting and 12 or 24 ducks were killed to determine body, carcase, breast-muscle, leg and thigh-muscle, and abdominal fat weights at time points from hatching until 53 d of age. 3. The Weibull function was chosen for growth curve analysis. The asymptote and inflection point from the Weibull growth curves identified 3 lines (Lines B, C, and D) with discrete body and carcase growth patterns but did not distinguish Line A from Line B. In all 4 lines the asymptote ranged from 4437 g to 3008 g for body weight and from 3334 g to 2098 g for carcase weight; the inflection point ranged from 22.5 d to 25.3 d for body weight and from 25.4 d to 29.6 d for carcase weight. 4. The allometric growth coefficient, relative to whole-body growth, was higher than 1.00 for breast muscle and lower than 1.00 for leg and thigh muscles during from 4 d to 53 d of age. 5. Body fat accumulation was estimated by abdominal fat. Line D accumulated more abdominal fat than other lines. The pattern of fat accumulation in Line D was different from Lines A, B and C and there were no differences between Lines A, B and C.

  13. The Impact of Real Exchange Rate on Economic Growth in Albania

    Directory of Open Access Journals (Sweden)

    Edmira Cakrani

    2014-02-01

    Full Text Available Real exchange rate is one of the most important economic variables, especially in today's conditions of integration processes, the removal of trade barriers and increasing direct competition between countries. Real exchange rate affects economy, through its impact on key economic variables, such as employment, inflation and especially economic growth. Changes in the real exchange rate affect the competitiveness of domestic products, resulting in increased exports or imports, affecting trade balance e growth. Also changes in the real exchange rate affect investment and capital accumulation, which are directly linked with economic growth. The aim of this paper is to study the possible impact of the real exchange rate on economic growth in Albania, to answer the question whether the real exchange rate can be used as an instrument of policy. Johansen cointegration method and Vector Error Correction Model is used in this paper to identify the longterm and short-term impact of real exchange rate on economic growth in Albania. Results of the study indicate that the real exchange rate has no significant impact on the Albanian economy, suggesting that policies to promote economic growth, both in the short and long term should not rely on this variable.

  14. Estimating blue whale skin isotopic incorporation rates and baleen growth rates: Implications for assessing diet and movement patterns in mysticetes.

    Science.gov (United States)

    Busquets-Vass, Geraldine; Newsome, Seth D; Calambokidis, John; Serra-Valente, Gabriela; Jacobsen, Jeff K; Aguíñiga-García, Sergio; Gendron, Diane

    2017-01-01

    Stable isotope analysis in mysticete skin and baleen plates has been repeatedly used to assess diet and movement patterns. Accurate interpretation of isotope data depends on understanding isotopic incorporation rates for metabolically active tissues and growth rates for metabolically inert tissues. The aim of this research was to estimate isotopic incorporation rates in blue whale skin and baleen growth rates by using natural gradients in baseline isotope values between oceanic regions. Nitrogen (δ15N) and carbon (δ13C) isotope values of blue whale skin and potential prey were analyzed from three foraging zones (Gulf of California, California Current System, and Costa Rica Dome) in the northeast Pacific from 1996-2015. We also measured δ15N and δ13C values along the lengths of baleen plates collected from six blue whales stranded in the 1980s and 2000s. Skin was separated into three strata: basale, externum, and sloughed skin. A mean (±SD) skin isotopic incorporation rate of 163±91 days was estimated by fitting a generalized additive model of the seasonal trend in δ15N values of skin strata collected in the Gulf of California and the California Current System. A mean (±SD) baleen growth rate of 15.5±2.2 cm y-1 was estimated by using seasonal oscillations in δ15N values from three whales. These oscillations also showed that individual whales have a high fidelity to distinct foraging zones in the northeast Pacific across years. The absence of oscillations in δ15N values of baleen sub-samples from three male whales suggests these individuals remained within a specific zone for several years prior to death. δ13C values of both whale tissues (skin and baleen) and potential prey were not distinct among foraging zones. Our results highlight the importance of considering tissue isotopic incorporation and growth rates when studying migratory mysticetes and provide new insights into the individual movement strategies of blue whales.

  15. Geographic after-tax real income differentials and population growth rates.

    Science.gov (United States)

    Alexander, G; Cebula, R J; Koch, J V

    1990-03-01

    "The purpose of this [one-page] note is to empirically investigate the impact of geographic after-tax real income differentials on geographic population growth rate differentials. The focus is on population growth rates in Florida's 67 counties over the period 1980-88." The authors conclude that "even after allowing for a variety of other location-influencing factors, including coastal access, after-tax real income differentials exercise a positive and significant impact on population growth rate differentials among Florida's counties."

  16. Determination of growth rates as an input of the stock discount valuation models

    Directory of Open Access Journals (Sweden)

    Momčilović Mirela

    2013-01-01

    Full Text Available When determining the value of the stocks with different stock discount valuation models, one of the important inputs is expected growth rate of dividends, earnings, cash flows and other relevant parameters of the company. Growth rate can be determined by three basic ways, and those are: on the basis of extrapolation of historical data, on the basis of professional assessment of the analytics who follow business of the company and on the basis of fundamental indicators of the company. Aim of this paper is to depict theoretical basis and practical application of stated methods for growth rate determination, and to indicate their advantages, or deficiencies.

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

    Indian Academy of Sciences (India)

    A Hasanbeigi; A Farhadian; E Khademi Bidhendi

    2014-06-01

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

  18. Do firms share the same functional form of their growth rate distribution? A new statistical test

    CERN Document Server

    Lunardi, Josè T; Lillo, Fabrizio; Mantegna, Rosario N; Gallegati, Mauro

    2011-01-01

    We introduce a new statistical test of the hypothesis that a balanced panel of firms have the same growth rate distribution or, more generally, that they share the same functional form of growth rate distribution. We applied the test to European Union and US publicly quoted manufacturing firms data, considering functional forms belonging to the Subbotin family of distributions. While our hypotheses are rejected for the vast majority of sets at the sector level, we cannot rejected them at the subsector level, indicating that homogenous panels of firms could be described by a common functional form of growth rate distribution.

  19. Ecological regime shift drives declining growth rates of sea turtles throughout the West Atlantic

    Science.gov (United States)

    Bjorndal, Karen A.; Bolten, Alan B.; Chaloupka, Milani; Saba, Vincent S.; Bellini, Cláudio; Marcovaldi, Maria A.G.; Santos, Armando J.B.; Bortolon, Luis Felipe Wurdig; Meylan, Anne B.; Meylan, Peter A.; Gray, Jennifer; Hardy, Robert; Brost, Beth; Bresette, Michael; Gorham, Jonathan C.; Connett, Stephen; Crouchley, Barbara Van Sciver; Dawson, Mike; Hayes, Deborah; Diez, Carlos E.; van Dam, Robert P.; Willis, Sue; Nava, Mabel; Hart, Kristen M.; Cherkiss, Michael S.; Crowder, Andrew; Pollock, Clayton; Hillis-Starr, Zandy; Muñoz Tenería, Fernando A.; Herrera-Pavón, Roberto; Labrada-Martagón, Vanessa; Lorences, Armando; Negrete-Philippe, Ana; Lamont, Margaret M.; Foley, Allen M.; Bailey, Rhonda; Carthy, Raymond R.; Scarpino, Russell; McMichael, Erin; Provancha, Jane A.; Brooks, Annabelle; Jardim, Adriana; López-Mendilaharsu, Milagros; González-Paredes, Daniel; Estrades, Andrés; Fallabrino, Alejandro; Martínez-Souza, Gustavo; Vélez-Rubio, Gabriela M.; Boulon, Ralf H.; Collazo, Jaime; Wershoven, Robert; Hernández, Vicente Guzmán; Stringell, Thomas B.; Sanghera, Amdeep; Richardson, Peter B.; Broderick, Annette C.; Phillips, Quinton; Calosso, Marta C.; Claydon, John A.B.; Metz, Tasha L.; Gordon, Amanda L.; Landry, Andre M.; Shaver, Donna J.; Blumenthal, Janice; Collyer, Lucy; Godley, Brendan J.; McGowan, Andrew; Witt, Matthew J.; Campbell, Cathi L.; Lagueux, Cynthia J.; Bethel, Thomas L.; Kenyon, Lory

    2017-01-01

    Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles – hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta – exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift (ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation (ENSO) – the strongest on record – combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures (SST) in the West Atlantic for years of declining growth rates (r = -0.94) and the Multivariate ENSO Index (MEI) for all years (r = 0.74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study

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

    Directory of Open Access Journals (Sweden)

    Dominick A Matos

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

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

    Science.gov (United States)

    Matos, Dominick A; Cole, Benjamin J; Whitney, Ian P; MacKinnon, Kirk J-M; Kay, Steve A; Hazen, Samuel P

    2014-01-01

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

  2. Follow-up of children and adolescents with short stature: the importance of the growth rate

    Directory of Open Access Journals (Sweden)

    Maria Wany Louzada Strufaldi

    Full Text Available CONTEXT AND OBJECTIVE: Short stature is defined as a height of more than two standard deviations below the average for a given age and sex in a reference population. The objective was to describe follow-up conducted among short-stature children and adolescents. DESIGN AND SETTING: Descriptive study, at the Growth outpatient clinic, Department of Pediatrics, Universidade Federal de São Paulo. METHODS: The study included 152 patients aged 2 to 15 years who had height for age of less than P5, on the National Center for Health Statistics curve. The children underwent nutritional evaluation, and several variables relating to height and growth rate were calculated to establish etiological diagnosis. Bone age was evaluated by X-ray. RESULTS: The majority (63.2% were male. In 77.8%, the stature observed was within the family pattern. Among the 99 patients followed up for more than 6 months, 17.2% presented inadequate growth rates. The preponderant etiological diagnosis for short stature was familial/constitutional in 58.6% of the cases; 27 patients (34.2% with adequate growth rate presented bone age alterations. Even with inadequate growth rates, 75% of such patients had a normal result from growth hormone stimulation testing. Close to 90% of patients with a diagnosis of short stature of familial/constitutional origin and intrauterine growth retardation presented adequate growth rate. The genetic etiology was significantly characteristic of patients with inadequate growth rate. CONCLUSION: Growth rate assessment must form part of the investigation and follow-up of short-stature cases. However, its utilization and validity should form part of an overall view of each patient.

  3. Diameter growth rates in tropical dry forests: contributions to the sustainable management of forests in the Bolivian Cerrado biogeographical province

    NARCIS (Netherlands)

    Lopez, L.; Villalba, R.; Peña-Claros, M.

    2012-01-01

    Growth ring variations were used to provide the rates in diameter growth for seven tree species in the Bolivian Cerrado biogeographical province. Ten to 50 trees were measured per species. Ring width measurements provided accurate data on the rates of tree growth. Variations in growth rates were det

  4. Factors Affecting Growth of Tengmalm's Owl (Aegolius funereus) Nestlings: Prey Abundance, Sex and Hatching Order.

    Science.gov (United States)

    Zárybnická, Markéta; Riegert, Jan; Brejšková, Lucie; Šindelář, Jiří; Kouba, Marek; Hanel, Jan; Popelková, Alena; Menclová, Petra; Tomášek, Václav; Šťastný, Karel

    2015-01-01

    In altricial birds, energy supply during growth is a major predictor of the physical condition and survival prospects of fledglings. A number of experimental studies have shown that nestling body mass and wing length can vary with particular extrinsic factors, but between-year observational data on this topic are scarce. Based on a seven-year observational study in a central European Tengmalm's owl population we examine the effect of year, brood size, hatching order, and sex on nestling body mass and wing length, as well as the effect of prey abundance on parameters of growth curve. We found that nestling body mass varied among years, and parameters of growth curve, i.e. growth rate and inflection point in particular, increased with increasing abundance of the owl's main prey (Apodemus mice, Microtus voles), and pooled prey abundance (Apodemus mice, Microtus voles, and Sorex shrews). Furthermore, nestling body mass varied with hatching order and between sexes being larger for females and for the first-hatched brood mates. Brood size had no effect on nestling body mass. Simultaneously, we found no effect of year, brood size, hatching order, or sex on the wing length of nestlings. Our findings suggest that in this temperate owl population, nestling body mass is more sensitive to prey abundance than is wing length. The latter is probably more limited by the physiology of the species.

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

    Energy Technology Data Exchange (ETDEWEB)

    Arganis Juárez, C.R., E-mail: carlos.arganis@inin.gob.mx; Hernández Callejas, R.; Medina Almazán, A.L.

    2015-05-15

    Highlights: • Two models were used to predict SCC growth rate in a core shroud of a BWR. • A weld residual stress distribution with 30% stress relaxation by neutron was used. • Agreement is shown between the measurements of SCC growth rate and the predictions. • Slip–oxidation model is better at low fluences and empirical model at high fluences. - Abstract: An empirical crack growth rate correlation model and a predictive model based on the slip–oxidation mechanism for Stress Corrosion Cracking (SCC) were used to calculate the crack growth rate in a BWR core shroud. In this study, the crack growth rate was calculated by accounting for the environmental factors related to aqueous environment, neutron irradiation to high fluence and the complex residual stress conditions resulting from welding. In estimating the SCC behavior the crack growth measurements data from a Boiling Water Reactor (BWR) plant are referred to, and the stress intensity factor vs crack depth throughout thickness is calculated using a generic weld residual stress distribution for a core shroud, with a 30% stress relaxation induced by neutron irradiation. Quantitative agreement is shown between the measurements of SCC growth rate and the predictions of the slip–oxidation mechanism model for relatively low fluences (5 × 10{sup 24} n/m{sup 2}), and the empirical model predicted better the SCC growth rate than the slip–oxidation model for high fluences (>1 × 10{sup 25} n/m{sup 2}). The relevance of the models predictions for SCC growth rate behavior depends on knowing the model parameters.

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

    Science.gov (United States)

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

    2016-06-01

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

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

    Science.gov (United States)

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

    2016-04-07

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

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

    Directory of Open Access Journals (Sweden)

    Donghun Lee

    2016-04-01

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

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

    Directory of Open Access Journals (Sweden)

    Flávio Vilela Vieira

    2012-09-01

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

  10. Comparative distribution of central neuropeptide Y (NPY) in the prairie (Microtus ochrogaster) and meadow (M. pennsylvanicus) vole.

    Science.gov (United States)

    Hostetler, Caroline M; Hitchcock, Leah N; Anacker, Allison M J; Young, Larry J; Ryabinin, Andrey E

    2013-02-01

    Neuropeptide Y (NPY) has been implicated as a modulator of social behavior, often in a species-specific manner. Comparative studies of closely related vole species are particularly useful for identifying neural systems involved in social behaviors in both voles and humans. In the present study, immunohistochemistry was performed to compare NPY-like immunoreactivity (-ir) in brain tissue of the socially monogamous prairie vole and non-monogamous meadow vole. Species differences in NPY-ir were observed in a number of regions including the cortex, extended amygdala, septal area, suprachiasmatic nucleus, and intergeniculate leaf. Meadow voles had higher NPY-ir in all these regions as compared to prairie voles. No differences were observed in the striatum or hippocampus. The extended amygdala and lateral septum are regions that play a key role in regulation of monogamous behaviors such as pair bonding and paternal care. The present study suggests NPY in these regions may be an additional modulator of these species-specific social behaviors. Meadow voles had moderately higher NPY-ir in a number of hypothalamic regions, especially in the suprachiasmatic nucleus. Meadow voles also had much higher levels of NPY-ir in the intergeniculate leaflet, another key region in the regulation of circadian rhythms. Overall, species differences in NPY-ir were observed in a number of brain regions implicated in emotion, stress, circadian, and social behaviors. These findings provide additional support for a role for the NPY system in species-typical social behaviors.

  11. The Effects of Population Density on Juvenile Growth Rate in White-Tailed Deer

    Science.gov (United States)

    Barr, Brannon; Wolverton, Steve

    2014-10-01

    Animal body size is driven by habitat quality, food availability, and nutrition. Adult size can relate to birth weight, to length of the ontogenetic growth period, and/or to the rate of growth. Data requirements are high for studying these growth mechanisms, but large datasets exist for some game species. In North America, large harvest datasets exist for white-tailed deer ( Odocoileus virginianus), but such data are collected under a variety of conditions and are generally dismissed for ecological research beyond local population and habitat management. We contend that such data are useful for studying the ecology of white-tailed deer growth and body size when analyzed at ordinal scale. In this paper, we test the response of growth rate to food availability by fitting a logarithmic equation that estimates growth rate only to harvest data from Fort Hood, Texas, and track changes in growth rate over time. Results of this ordinal scale model are compared to previously published models that include additional parameters, such as birth weight and adult weight. It is shown that body size responds to food availability by variation in growth rate. Models that estimate multiple parameters may not work with harvest data because they are prone to error, which renders estimates from complex models too variable to detect interannual changes in growth rate that this ordinal scale model captures. This model can be applied to harvest data, from which inferences about factors that influence animal growth and body size (e.g., habitat quality and nutritional availability) can be drawn.

  12. In situ growth rates of deep-water octocorals determined from 3D photogrammetric reconstructions

    Science.gov (United States)

    Bennecke, Swaantje; Kwasnitschka, Tom; Metaxas, Anna; Dullo, Wolf-Christian

    2016-12-01

    Growth rates of deep-water corals provide important information on the recovery potential of these ecosystems, for example from fisheries-induced impacts. Here, we present in situ growth dynamics that are currently largely unknown for deep-water octocorals, calculated by applying a non-destructive method. Videos of a boulder harbouring multiple colonies of Paragorgia arborea and Primnoa resedaeformis in the Northeast Channel Coral Conservation Area at the entrance to the Gulf of Maine at 863 m depth were collected in 2006, 2010 and 2014. Photogrammetric reconstructions of the boulder and the fauna yielded georeferenced 3D models for all sampling years. Repeated measurements of total length and cross-sectional area of the same colonies allowed the observation of growth dynamics. Growth rates of total length of Paragorgia arborea decreased over time with higher rates between 2006 and 2010 than between 2010 and 2014, while growth rates of cross-sectional area remained comparatively constant. A general trend of decreasing growth rates of total length with size of the coral colony was documented. While no growth was observed for the largest colony (165 cm in length) between 2010 and 2014, a colony 50-65 cm in length grew 3.7 cm yr-1 between 2006 and 2010. Minimum growth rates of 1.6-2.7 cm yr-1 were estimated for two recruits (<23 cm in 2014) of Primnoa resedaeformis. We successfully extracted biologically meaningful data from photogrammetric models and present the first in situ growth rates for these coral species in the Northwest Atlantic.

  13. Calorimetric control of the specific growth rate during fed-batch cultures of Saccharomyces cerevisiae.

    Science.gov (United States)

    Biener, Richard; Steinkämper, Anne; Horn, Thomas

    2012-08-31

    The specific growth rate of a Saccharomyces cerevisiae strain with glucose as limiting C-source was estimated from the measured heat flow produced by the cells. For the cultivation a standard 30 l laboratory bioreactor was used, which was extended in such a way that heat balancing is possible. The feed rate was adjusted by a feedforward/feedback controller such that the specific growth rate was kept on the desired set-point value. On the basis of experimental investigations it was demonstrated that the specific growth rate can be controlled at a given set point value below the critical value to prevent the production of growth-inhibitory ethanol due to the Crabtree effect. With this control strategy high biomass concentrations of more than 110 g l(-1) can be obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Effects of the flow rate of hydrogen on the growth of graphene

    Institute of Scientific and Technical Information of China (English)

    Yong-gui Shi; Yue Hao; Dong Wang; Jin-cheng Zhang; Peng Zhang; Xue-fang Shi; Dang Han; Zheng Chai; Jing-dong Yan

    2015-01-01

    Graphene samples with different morphologies were fabricated on the inside of copper enclosures by low pressure chemical vapor deposition and tuning the flow rate of hydrogen. It is found that the flow rate of hydrogen greatly influences the growth of graphene. Ther-modynamic analysis indicates that a higher flow rate of hydrogen is favorable to the formation of good quality graphene with regular mor-phology. However, the mass-transfer process of methane dominates the growth driving force. At very low pressure, mass-transfer proceeds by Knudsen diffusion, and the mass-transfer flux of methane decreases as the flow rate of hydrogen increases, leading to a decrease in the growth driving force. At a higher pressure, mass-transfer proceeds by Fick’s diffusion, and the mass-transfer flux of methane is dominated by the gas velocity, whose variation determines the growth driving force variation of graphene.

  15. Modelling the effect of ethanol on growth rate of food spoilage moulds

    NARCIS (Netherlands)

    Dantigny, P.; Guilmart, A.; Radoi, F.; Bensoussan, M.; Zwietering, M.H.

    2005-01-01

    The effect of ethanol (E) on the radial growth rate (¿) of food spoilage moulds (Aspergillus candidus, Aspergillus flavus, Aspergillus niger, Cladosporium cladosporioides, Eurotium herbariorum, Mucor circinelloides, Mucor racemosus, Paecilomyces variotii, Penicillium chrysogenum, Penicillium digitat

  16. Dependence of growth rate of quartz in fused silica on pressure and impurity content

    Science.gov (United States)

    Fratello, V. J.; Hays, J. F.; Turnbull, D.

    1980-01-01

    The effects of pressure, temperature, and some variations in impurity content on the growth rate u of quartz into fused silica were measured. Under all conditions the growth rate was interface controlled and increased exponentially with pressure with an activation volume averaging -21.2 cu cm/mole. The activation enthalpy for all specimens is extrapolated to a zero pressure value of 64 kcal/mole, within the experimental uncertainty. At a given stoichiometry the effect of hydroxyl content on growth rate is described entirely by a linear term C(OH) in the prefactor of the equation for the growth rate. The effect of chlorine impurity can be described similarly. Also u is increased as the ideal stoichiometry is approached from the partially reduced state.

  17. Revision of bank vole Clethrionomys glareolus (Schreber, 1780 (Mammalia, Rodentia distribution in Serbia and Montenegro

    Directory of Open Access Journals (Sweden)

    Paunović M.

    2005-01-01

    Full Text Available The present article represents a complete review of all published data (with corrections on bank vole Clethrionomys glareolus distribution in Serbia and Montenegro. On the other hand, data of 63 unpublished records stored in the period from 1956 to 1983 in the Mammal Study Collection of the Natural History Museum, Belgrade had not been processed until now. In the period from 1992 to 2004, 29 new findings were recorded, 12 of them outside the currently known area of distribution. New data reveal a wider distribution of bank vole than was known until now, completing and partly modifying previous knowledge about this rodent's bionomy and ecology in Serbia and Montenegro. The occurrence of bank vole in the Prokletije Mountains, Kosovo and Metohija represents its highest known altitude in Europe (2500 m. On the basis of these new data and observations, we can conclude that bank vole is continuously present in small and linear fragments of autochthonous woodlands on plains and hills, and that there are no large discontinuities in its distribution in Serbia and Montenegro, as was assumed earlier. In efforts to preserve overall biological diversity, the example of the bank vole underlines the need to intensify protection and management of woodlands especially remaining fragments of forests on plains and in hills.

  18. Growth rates of alien Oreochromis niloticus and indigenous Oreochromis mortimeri in Lake Kariba, Zimbabwe

    NARCIS (Netherlands)

    Chifamba, P. C.; Videler, J. J.

    2014-01-01

    Growth rates of indigenous Oreochromis mortimeri and alien Oreochromis niloticus from Lake Kariba were estimated from samples collected in 1997-2000, 2003-2005 and 2010-2011. Growth zones on scales and otoliths of O. niloticus and on the otoliths and opercula of O. mortimeri were deposited annually.

  19. Mechanisms promoting higher growth rate in arctic than in temperate shorebirds

    NARCIS (Netherlands)

    Schekkerman, H; Tulp, Ingrid; Piersma, T.; Visser, G.H.

    2003-01-01

    We compared prefledging growth, energy expenditure, and time budgets in the arctic-breeding red knot (Calidris canutus) to those in temperate shorebirds, to investigate how arctic chicks achieve a high growth rate despite energetic difficulties associated with precocial development in a cold climate

  20. Hereditary breast cancer growth rates and its impact on screening policy.

    NARCIS (Netherlands)

    Tilanus-Linthorst, M.M.; Kriege, M.; Boetes, C.; Hop, W.C.J.; Obdeijn, I.M.; Oosterwijk-Wakka, J.C.; Peterse, H.L.; Zonderland, H.M.; Meijer, S.; Eggermont, A.M.M.; Koning, H.J. de; Klijn, J.G.M.; Brekelmans, C.T.

    2005-01-01

    Imaging is often performed yearly for the surveillance of BRCA1/2 mutation carriers and women at high familial breast cancer risk. Growth of cancers in carriers may be faster as these tumours are predominantly high grade. Quantitative data on tumour growth rates in these 2 groups are lacking. Here,

  1. Hereditary breast cancer growth rates and its impact on screening policy

    NARCIS (Netherlands)

    Tilanus-Linthorst, Madeleine M.A.; Kriege, Mieke; Boetes, Carla; Hop, Wim C.J.; Obdeijn, Inge-Marie; Oosterwijk, Jan C.; Peterse, Hans L.; Zonderland, Harmine M.; Meijer, Sybren; Eggermont, Alexander M.M.; De Koning, Harry J.; Klijn, Jan G.M.; Brekelmans, Cecile T.M.

    2005-01-01

    Imaging is often performed yearly for the surveillance of BRCA1/2 mutation carriers and women at high familial breast cancer risk. Growth of cancers in carriers may be faster as these tumours are predominantly high grade. Quantitative data on tumour growth rates in these 2 groups are lacking. Here,

  2. Growth rate and chemical composition of a manganese nodule from the EEZ of Seychelles

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.; Borole, D.V.

    mhe ferro-manganese nodule collected in EEZ of Seychelles yields a growth rate of 1.5 mm/10 6Y 230Th (ex)/ and 230Th (ex)/ 232Th activity ratio methods indicating very slow growth of ferro-manganese nodules. The Mn/Fe and U/Th ratios suggest...

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

    Science.gov (United States)

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

    2008-01-01

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

  4. The Quantum Effects Role on Weibel Instability Growth Rate in Dense Plasma

    Directory of Open Access Journals (Sweden)

    M. Mahdavi

    2015-01-01

    effects and density gradient tend to stabilize the Weibel instability. The density perturbations have decreased the growth rate of Weibel instability in the near corona fuel, η>0.1. In the small wavelengths limit, for the density gradient, η<0.1, the tunneling quantum effects increase anisotropy in the phase space. The quantum tunneling effect leads to an unexpected increase in the Weibel instability growth rate.

  5. Oscillatory, stochastic and chaotic growth rate fluctuations in permittistatically controlled yeast cultures.

    Science.gov (United States)

    Davey, H M; Davey, C L; Woodward, A M; Edmonds, A N; Lee, A W; Kell, D B

    1996-01-01

    We describe a continuous culture system related to the turbidostat, but using a feedback system based on biomass estimation from the dielectric permittivity of the cell suspension rather than its optical density. It is shown that this system provides an excellent method of maintaining a constant biomass level within a fermentor. The computer-controlled system was able to effect the essentially continuous registration of growth rate by monitoring the rate of medium addition via the time-dependent activity of the pump. At some biomass setpoints for aerobically grown cultures of baker's yeast substantial time-dependent fluctuations in the growth rate of the culture were thereby observed. At some biomass setpoints, however, or under anaerobic conditions, or when using a non-Crabtree yeast, the growth rate was constant, indicating that the fluctuations were inherent to the biological system and not simply a property of the fermentor and control system. A variety of time series analyses (Fourier transformations, Hurst and Lyapunov exponents, the determination of embedding dimension, and non-linear time series predictions based on the methodology of Sugihara and May) were used to demonstrate, for the first time, that as well as stochastic and periodic components these fluctuations exhibited deterministic chaos. 'Trivial predictors' were unable to give accurate predictions of the growth rate in these cultures. The growth rate fluctuations were studied further by means of offline measurements of changes in percentage viability, bud count, and in the external ethanol and glucose concentrations; these data and other evidence suggested that the growth rate fluctuations were closely linked to the primary respiro-fermentative metabolism of this organism. The identification of chaotic growth rates in cell cultures suggests that there may be novel methods for controlling the growth of such cultures.

  6. Population growth, saving, interest rates and stagnation: Discussing the Eggertsson-Mehrotra model

    OpenAIRE

    Spahn, Peter

    2016-01-01

    Post Keynesian stagnation theory argues that slower population growth dampens consumption and investment. A New Keynesian OLG model derives an unemployment equilibrium due to a negative natural rate in a three-generations credit contract framework. Besides deleveraging or rising inequality, also a shrinking population is a triggering factor. In all cases, a saving surplus drives real interest rates down. In other OLG settings however, with bonds as stores of value, slower population growth, o...

  7. Growth Rate Analysis and Efficient Experimental Design for Tumor Xenograft Studies

    OpenAIRE

    Gregory Hather; Ray Liu; Syamala Bandi; Jerome Mettetal; Mark Manfredi; Wen-Chyi Shyu; Jill Donelan; Arijit Chakravarty

    2014-01-01

    Human tumor xenograft studies are the primary means to evaluate the biological activity of anticancer agents in late-stage preclinical drug discovery. The variability in the growth rate of human tumors established in mice and the small sample sizes make rigorous statistical analysis critical. The most commonly used summary of antitumor activity for these studies is the T/C ratio. However, alternative methods based on growth rate modeling can be used. Here, we describe a summary metric called ...

  8. Autolabelling of gamasid mites and fleas in nests of red voles in winter (according to radioisotope labelling data)

    Energy Technology Data Exchange (ETDEWEB)

    Al' bov, S.A.; Lavrenchenko, L.A.; Nikolaeva, G.A.

    Data concerning trophic associations between gamasid mites and fleas in cohabitation with red voles in nests in winter were presented and discussed. Red voles (Cl. glareolus) were trapped, labelled with radioactive cobalt and radioactive glycine, released and traced with the aid of radiometers. H. nidi and C. penicilliger were found to be the most numerous among the mites and fleas in the winter nests of the voles and were the most actively feeding species. H. nidi and C. penicilliger numbers increased with the increase of time of use of the nests by the voles and had little relationship to the abundance of these species in the nests. Other species assumed that the connection between the gamasid mites, fleas and voles was topical rather than trophic. 11 references, 4 figures.

  9. Landscape scale measures of steelhead (Oncorhynchus mykiss) bioenergetic growth rate potential in Lake Michigan and comparison with angler catch rates

    Science.gov (United States)

    Hook, T.O.; Rutherford, E.S.; Brines, Shannon J.; Geddes, C.A.; Mason, D.M.; Schwab, D.J.; Fleischer, G.W.

    2004-01-01

    The relative quality of a habitat can influence fish consumption, growth, mortality, and production. In order to quantify habitat quality, several authors have combined bioenergetic and foraging models to generate spatially explicit estimates of fish growth rate potential (GRP). However, the capacity of GRP to reflect the spatial distributions of fishes over large areas has not been fully evaluated. We generated landscape scale estimates of steelhead (Oncorhynchus mykiss) GRP throughout Lake Michigan for 1994-1996, and used these estimates to test the hypotheses that GRP is a good predictor of spatial patterns of steelhead catch rates. We used surface temperatures (measured with AVHRR satellite imagery) and acoustically measured steelhead prey densities (alewife, Alosa pseudoharengus) as inputs for the GRP model. Our analyses demonstrate that potential steelhead growth rates in Lake Michigan are highly variable in both space and time. Steelhead GRP tended to increase with latitude, and mean GRP was much higher during September 1995, compared to 1994 and 1996. In addition, our study suggests that landscape scale measures of GRP are not good predictors of steelhead catch rates throughout Lake Michigan, but may provide an index of interannual variation in system-wide habitat quality.

  10. Rate of head circumference growth as a function of autism diagnosis and history of autistic regression.

    Science.gov (United States)

    Webb, Sara Jane; Nalty, Theresa; Munson, Jeff; Brock, Catherine; Abbott, Robert; Dawson, Geraldine

    2007-10-01

    Several reports indicate that autism spectrum disorder is associated with increased rate of head growth in early childhood. Increased rate of growth may index aberrant processes during early development, may precede the onset of symptoms, and may predict severity of the disease course. We examined rate of change in occipitofrontal circumference measurements (abstracted from medical records) in 28 boys with autism spectrum disorder and in 8 boys with developmental delay without autism from birth to age 36 months. Only children who had more than 3 occipitofrontal circumference measurements available during this age period were included. All data were converted to z scores based on the Centers for Disease Control and Prevention norms. Rate of growth from birth to age 36 months was statistically significantly higher for the autism spectrum disorder group than the developmental delay group, with children with autism spectrum disorder showing a statistically significant increase in occipitofrontal circumference relative to norms between 7 and 10 months; this group difference in rate of growth was more robust when height was used as a covariate. Rate of growth was not found to be different for children with autism spectrum disorder whose parents reported a history of loss of skills (regression) vs those whose parents reported early onset of autism symptoms. Findings from this study suggest that the aberrant growth is present in the first year of life and precedes the onset and diagnosis in children with autism spectrum disorder with and without a history of autistic regression.

  11. Effect of growth rate on characteristic lengths of microstructure in directionally solidified

    Directory of Open Access Journals (Sweden)

    Zhang Yuan

    2013-09-01

    Full Text Available The microstructure of TiAl based alloys is sensitive to growth rates. In this paper, Bridgman directional solidification of Ti-46Al-2Cr-2Nb-0.2B (at.% alloy was carried out at a constant temperature gradient (G to investigate the effects of various growth rates (v on characteristic lengths (primary dendritic arm spacing, secondary dendritic arm spacing and lamellar spacing of the microstructure. Results show that under the experimental conditions of G = 18 K·m-1 and v = 15 μm·s-1 to 70 μm·s-1, the primary phase of directionally solidified Ti-46Al-2Cr-2Nb-0.2B alloy is α phase, the values of primary dendritic arm spacing (λ1, secondary dendritic arm spacing (λ2 and lamellar spacing (λ1a decrease with the increase in growth rate. The results were compared with theoretical models and similar experimental results of TiAl based alloys. The Bouchard-Kirkaldy model agrees well with the relationship between primary dendritic arm spacing and growth rate obtained in the experiment; the relationship between them can be expressed by λ1 = 758.6v-0.39. The relationship between the secondary dendritic arm spacing and the growth rate can be expressed by λ2 = 113.9v-0.45, while the relationship between the lamellar spacing and growth rate can be expressed by λ1a = 22.88v-0.94.

  12. Prediction of microbial growth rate versus biomass yield by a metabolic network with kinetic parameters.

    Science.gov (United States)

    Adadi, Roi; Volkmer, Benjamin; Milo, Ron; Heinemann, Matthias; Shlomi, Tomer

    2012-01-01

    Identifying the factors that determine microbial growth rate under various environmental and genetic conditions is a major challenge of systems biology. While current genome-scale metabolic modeling approaches enable us to successfully predict a variety of metabolic phenotypes, including maximal biomass yield, the prediction of actual growth rate is a long standing goal. This gap stems from strictly relying on data regarding reaction stoichiometry and directionality, without accounting for enzyme kinetic considerations. Here we present a novel metabolic network-based approach, MetabOlic Modeling with ENzyme kineTics (MOMENT), which predicts metabolic flux rate and growth rate by utilizing prior data on enzyme turnover rates and enzyme molecular weights, without requiring measurements of nutrient uptake rates. The method is based on an identified design principle of metabolism in which enzymes catalyzing high flux reactions across different media tend to be more efficient in terms of having higher turnover numbers. Extending upon previous attempts to utilize kinetic data in genome-scale metabolic modeling, our approach takes into account the requirement for specific enzyme concentrations for catalyzing predicted metabolic flux rates, considering isozymes, protein complexes, and multi-functional enzymes. MOMENT is shown to significantly improve the prediction accuracy of various metabolic phenotypes in E. coli, including intracellular flux rates and changes in gene expression levels under different growth rates. Most importantly, MOMENT is shown to predict growth rates of E. coli under a diverse set of media that are correlated with experimental measurements, markedly improving upon existing state-of-the art stoichiometric modeling approaches. These results support the view that a physiological bound on cellular enzyme concentrations is a key factor that determines microbial growth rate.

  13. Rapid, bilateral changes in growth rate and curvature during gravitropism of cucumber hypocotyls: implications for mechanism of growth control

    Science.gov (United States)

    Cosgrove, D. J.

    1990-01-01

    The growth response of etiolated cucumber (Cucumis sativus L.) hypocotyls to gravitropic stimulation was examined by means of time-lapse photography and high-resolution analysis of surface expansion and curvature. In comparison with video analysis, the technique described here has five- to 20-fold better resolution; moreover, the mathematical fitting method (cubic splines) allows direct estimation of local and integrated curvature. After switching seedlings from a vertical to horizontal position, both upper and lower surfaces of the stem reacted after a lag of about 11 min with a two- to three-fold increase in surface expansion rate on the lower side and a cessation of expansion, or slight compression, on the upper surface. This growth asymmetry was initiated simultaneously along the length of the hypocotyl, on both upper and lower surfaces, and did not migrate basipetally from the apex. Later stages in the gravitropic response involved a complex reversal of the growth asymmetry, with the net result being a basipetal migration of the curved region. This secondary growth reversal may reflect oscillatory and/or self-regulatory behaviour of growing cells. With some qualifications, the kinetics and pattern of growth response are consistent with a mechanism involving hormone redistribution, although they do not prove such a mechanism. The growth kinetics require a growth mechanism which can be stimulated by two- to three-fold or completely inhibited within a few minutes.

  14. Diagnostic Accuracy of Growth Rate in Differentiating Etiologies of Short Stature in Children

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Alaei

    2016-08-01

    Full Text Available Background  Short stature is a manifestation of a wide variety of conditions that some of which may be amenable to timely treatment and a suboptimal growth rate may be an early marker pointing to the cause of growth retardation. This study was conducted to evaluate the diagnostic utility of growth rate in differential diagnosis of children with short stature. Materials and Methods All children between the ages of 2 and 18 years who visited in pediatric endocrinology clinic in a five years period were recruited in a prospective cohort study. Children with standing height Results One hundred forty three patients fulfilled the inclusion criteria. Mean follow up period was 14.4±10.9 months. Etiologies of short stature were: constitutional growth delay (CGD 46.9%, familial short stature (FSS 28.7%, hypothyroidism 4.2%, growth hormone deficiency (GHD 4.2% and miscellaneous causes in 16% of patients.  Mean Z- score for children with constitutional growth delay was -2.3±0.69, in familial short stature was -2.3±0.65 and for other condition was -2.7±1.49. There was a meaningful statistical correlation between growth rate and etiology of short stature (P0.05. Conclusion There was significant difference in growth rate between children with constitutional growth delay and familial short stature in comparing to short stature due to endocrine problem and other etiologies. Assessment of growth rate has some utility in diagnosing the etiology of short stature.

  15. Phytoplankton growth rate and nitrogen content: Implications for feeding and fecundity in a herbivorous copepod

    DEFF Research Database (Denmark)

    Kiørboe, Thomas

    1989-01-01

    at a concentration of 1.5 ppm. Over more than 2 orders of magnitude increase in algal growth rate, the ingested cell volume increased by less than a factor of 2, ingested carbon remained constant whereas ingested nitrogen as well as rate of egg production increased by a factor of ca 6. Variation in ingested cell......Observations of natural feeding and egg-production rates of planktonic copepods have revealed distinct responses, independent of phytoplankton biomass, to oceanographic processes that fertilize the photic layer. Are such responses caused by changes in phytoplankton growth rate, influencing feeding...... behaviour, and/or by changes in the chemical composition of the phytoplankton, influencing fecundity? The diatom Thalassiosira weissflogii, grown in continuous cultures at different dilution rates and different nitrogen concentrations in the growth medium, was offered to the copepod Acartia tonsa...

  16. Anisotropic interpolation method of silicon carbide oxidation growth rates for three-dimensional simulation

    Science.gov (United States)

    Šimonka, Vito; Nawratil, Georg; Hössinger, Andreas; Weinbub, Josef; Selberherr, Siegfried

    2017-02-01

    We investigate anisotropical and geometrical aspects of hexagonal structures of Silicon Carbide and propose a direction dependent interpolation method for oxidation growth rates. We compute three-dimensional oxidation rates and perform one-, two-, and three-dimensional simulations for 4H- and 6H-Silicon Carbide thermal oxidation. The rates of oxidation are computed according to the four known growth rate values for the Si- (0 0 0 1) , a- (1 1 2 bar 0) , m- (1 1 bar 0 0) , and C-face (0 0 0 1 bar) . The simulations are based on the proposed interpolation method together with available thermal oxidation models. We additionally analyze the temperature dependence of Silicon Carbide oxidation rates for different crystal faces using Arrhenius plots. The proposed interpolation method is an essential step towards highly accurate three-dimensional oxide growth simulations which help to better understand the anisotropic nature and oxidation mechanism of Silicon Carbide.

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    Colonisation by stream plants occurs to a large extent from simple stem fragments. Allofragments are stem fragments formed by mechanical breakage. We studied regeneration, colonisation, and growth rates in four common stream plants: Elodea canadensis Michx., Myriophyllum spicatum L., Potamogeton...... perfoliatus L. and Ranunculus baudotii x pseudofluitans. The objectives of this study were to determine (1) if shoots with an apical tip have higher regeneration (growth of new shoots and rhizomes from allofragments) and colonisation (root attachment in sediment) abilities and higher relative growth rates...

  18. 7075-T6 and 2024-T351 Aluminum Alloy Fatigue Crack Growth Rate Data

    Science.gov (United States)

    Forth, Scott C.; Wright, Christopher W.; Johnston, William M., Jr.

    2005-01-01

    Experimental test procedures for the development of fatigue crack growth rate data has been standardized by the American Society for Testing and Materials. Over the past 30 years several gradual changes have been made to the standard without rigorous assessment of the affect these changes have on the precision or variability of the data generated. Therefore, the ASTM committee on fatigue crack growth has initiated an international round robin test program to assess the precision and variability of test results generated using the standard E647-00. Crack growth rate data presented in this report, in support of the ASTM roundrobin, shows excellent precision and repeatability.

  19. Effects of climate change on plant population growth rate and community composition change.

    Science.gov (United States)

    Chang, Xiao-Yu; Chen, Bao-Ming; Liu, Gang; Zhou, Ting; Jia, Xiao-Rong; Peng, Shao-Lin

    2015-01-01

    The impacts of climate change on forest community composition are still not well known. Although directional trends in climate change and community composition change were reported in recent years, further quantitative analyses are urgently needed. Previous studies focused on measuring population growth rates in a single time period, neglecting the development of the populations. Here we aimed to compose a method for calculating the community composition change, and to testify the impacts of climate change on community composition change within a relatively short period (several decades) based on long-term monitoring data from two plots-Dinghushan Biosphere Reserve, China (DBR) and Barro Colorado Island, Panama (BCI)-that are located in tropical and subtropical regions. We proposed a relatively more concise index, Slnλ, which refers to an overall population growth rate based on the dominant species in a community. The results indicated that the population growth rate of a majority of populations has decreased over the past few decades. This decrease was mainly caused by population development. The increasing temperature had a positive effect on population growth rates and community change rates. Our results promote understanding and explaining variations in population growth rates and community composition rates, and are helpful to predict population dynamics and population responses to climate change.

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

    Directory of Open Access Journals (Sweden)

    B. Verheggen

    2006-01-01

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

  1. Effects of climate change on plant population growth rate and community composition change.

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Chang

    Full Text Available The impacts of climate change on forest community composition are still not well known. Although directional trends in climate change and community composition change were reported in recent years, further quantitative analyses are urgently needed. Previous studies focused on measuring population growth rates in a single time period, neglecting the development of the populations. Here we aimed to compose a method for calculating the community composition change, and to testify the impacts of climate change on community composition change within a relatively short period (several decades based on long-term monitoring data from two plots-Dinghushan Biosphere Reserve, China (DBR and Barro Colorado Island, Panama (BCI-that are located in tropical and subtropical regions. We proposed a relatively more concise index, Slnλ, which refers to an overall population growth rate based on the dominant species in a community. The results indicated that the population growth rate of a majority of populations has decreased over the past few decades. This decrease was mainly caused by population development. The increasing temperature had a positive effect on population growth rates and community change rates. Our results promote understanding and explaining variations in population growth rates and community composition rates, and are helpful to predict population dynamics and population responses to climate change.

  2. Chick metabolic rate and growth in three species of albatross: a comparative study.

    Science.gov (United States)

    Phillips, R A; Green, J A; Phalan, B; Croxall, J P; Butler, P J

    2003-05-01

    The relative importance of genetic vs. environmental factors in determining the pattern of avian post-embryonic development is much debated. Previous cross-fostering of albatrosses suggested that although inter-specific variation in growth rate was determined primarily by differences in dietary energy content, species-specific constraints might have evolved that could limit maximal growth, even in chicks fed at similar rates and on similar diets. This study aimed to determine whether intrinsic differences in resting metabolic rate were apparent during the linear phase of growth in chicks of three species (black-browed, grey-headed and light-mantled sooty albatrosses). There was a gradual increase in absolute, and a reduction in mass-specific metabolic rate from 5.0 W kg(-1) during the earliest part of linear growth, to 3.5 W kg(-1) by the time chicks reached peak mass. These values are considerably higher than in resting adults of comparable or lower mass, presumably reflecting the large size and high metabolic demand of organs involved in rapid nutrient processing and tissue synthesis by chicks. The lack of any detectable inter-specific variation in the pattern of metabolic rate changes casts some doubt on the existence of fundamental differences in growth rate that cannot be attributed simply to differences in dietary energy or nutrient delivery rate.

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

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

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

  4. Quantitative Physiology of Saccharomyces cerevisiae at Near-Zero Specific Growth Rates

    Science.gov (United States)

    Boender, Léonie G. M.; de Hulster, Erik A. F.; van Maris, Antonius J. A.; Daran-Lapujade, Pascale A. S.; Pronk, Jack T.

    2009-01-01

    Growth at near-zero specific growth rates is a largely unexplored area of yeast physiology. To investigate the physiology of Saccharomyces cerevisiae under these conditions, the effluent removal pipe of anaerobic, glucose-limited chemostat culture (dilution rate, 0.025 h−1) was fitted with a 0.22-μm-pore-size polypropylene filter unit. This setup enabled prolonged cultivation with complete cell retention. After 22 days of cultivation, specific growth rates had decreased below 0.001 h−1 (doubling time of >700 h). Over this period, viability of the retentostat cultures decreased to ca. 80%. The viable biomass concentration in the retentostats could be accurately predicted by a maintenance coefficient of 0.50 mmol of glucose g−1 of biomass h−1 calculated from anaerobic, glucose-limited chemostat cultures grown at dilution rates of 0.025 to 0.20 h−1. This indicated that, in contrast to the situation in several prokaryotes, maintenance energy requirements in S. cerevisiae do not substantially change at near-zero specific growth rates. After 22 days of retentostat cultivation, glucose metabolism was predominantly geared toward alcoholic fermentation to meet maintenance energy requirements. The strict correlation between glycerol production and biomass formation observed at higher specific growth rates was not maintained at the near-zero growth rates reached in the retentostat cultures. In addition to glycerol, the organic acids acetate, d-lactate, and succinate were produced at low rates during prolonged retentostat cultivation. This study identifies robustness and by-product formation as key issues in attempts to uncouple growth and product formation in S. cerevisiae. PMID:19592533

  5. Morphotype analysis of the sibling vole (Microtus rossiaemeridionalis) casually introduced to the Russian Far East.

    Science.gov (United States)

    Tiunov, Mikhail Petrovich; Kartavtseva, Irina Vasiljevna; Lapin, Alexander Sergeevich

    2013-01-01

    Here, we present the morphotypic variety of the m1 and M3 teeth diagnostics for the recently formed isolated population of the sibling vole in Far Eastern Russia. In the Far Eastern population, the prevalence of the individuals with m1 with a complicated crown of the forward unpaired loop of the paraconid is characteristic. Namely, m1 in these individuals shows well-expressed sixth exterior and fifth interior salient angles. The structure of the M3 morphotypes is also unique in the sibling voles in Far Eastern Russia. The dominant morphotypes were typica (47 %) and simplex (45 %), whereas the abundance of the duplicata morphotype was 0.08 %. The frequencies of various m1 and M3 morphotypes found in casually introduced sibling voles in the Far East are not typical of any previously studied Microtus rossiaemeridionalis population.

  6. Infection of SARS-CoV on juvenile and adult Brandt's vole Microtus brandtii

    Institute of Scientific and Technical Information of China (English)

    GAO Hong; PENG Jingpian; DENG Wei; SHI Dazhao; BAO Linlin; WANG Dehua; ZHANG Binglin; QIN Chuan; ZHANG Zhibin

    2005-01-01

    We studied the infectious effect of SARS-CoV virus on juvenile and adult Brandt's Vole (Microtus brandtii) by nasal cavity spraying method (CCID50 is 105.7). SARS virus caused serious deaths in adults. The death adults demonstrated hemorrhage from mouth, nasal cavity and intestine, hemorrhageious interstitial pneumonia and gore in liver, spleen and kidney. The survival adults demonstrated local hemorrhagic spot in lung and emphysema, but the other organs showed no pathological abnormality. SARS virus caused no deaths in juveniles, but locomotion of infected juveniles became slower. In the early stage, there was local pneumonia in lung and SARS viruses were isolated from the pathological tissue. Only one control juvenile lived and the infected juvenile showed local pneumonia in lung. The results demonstrated that SARS-CoV infected Brandt's vole seriously and adults were more susceptive to SARS-CoV than juveniles. The Brandt's vole may be a potential animal model for SARS research.

  7. DIFFERENCES IN POST HATCH METABOLIC RATE AND DEVELOPMENTAL RATE IN ATLANTIC SALMON (SALMO SALAR L): EVIDENCE FOR COMPENSATORY GROWTH?

    DEFF Research Database (Denmark)

    Steffensen, John Fleng

    2010-01-01

    in six out of 91 families, the three families with earliest and the three families with latest time to hatch. Measurements were done on two occasions, at 570-580 (T1) and 600-610 (T2) day degrees from fertilization. Generally, VO2 increased and yolk was consumed between T1 and T2. Late hatching larvae...... and had higher metabolic rate in T1 suggests that these inherited differences can be even out by accelerated post hatch growth....

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

    DEFF Research Database (Denmark)

    Yang, Lei; Haagensen, Janus Anders Juul; Jelsbak, Lars;

    2008-01-01

    The growth dynamics of bacterial pathogens within infected hosts are a fundamental but poorly understood feature of most infections. We have focused on the in situ distribution and growth characteristics of two prevailing and transmissible Pseudomonas aeruginosa clones that have caused chronic lung...... matrix, whereas nonmucoid variants were present mainly as dispersed cells. To obtain estimates of the growth rates of P. aeruginosa in CF lungs, we used quantitative FISH to indirectly measure growth rates of bacteria in sputum samples (reflecting the in vivo lung conditions). The concentration of r......RNA in bacteria isolated from sputa was measured and correlated with the rRNA contents of the same bacteria growing in vitro at defined rates. The results showed that most cells were actively growing with doubling times of between 100 and 200 min, with some growing even faster. Only a small stationary...

  9. Maximum Rate of Growth of Enstrophy in Solutions of the Fractional Burgers Equation

    CERN Document Server

    Yun, Dongfang

    2016-01-01

    This investigation is a part of a research program aiming to characterize the extreme behavior possible in hydrodynamic models by probing the sharpness of estimates on the growth of certain fundamental quantities. We consider here the rate of growth of the classical and fractional enstrophy in the fractional Burgers equation in the subcritical, critical and supercritical regime. First, we obtain estimates on these rates of growth and then show that these estimates are sharp up to numerical prefactors. In particular, we conclude that the power-law dependence of the enstrophy rate of growth on the fractional dissipation exponent has the same global form in the subcritical, critical and parts of the supercritical regime. This is done by numerically solving suitably defined constrained maximization problems and then demonstrating that for different values of the fractional dissipation exponent the obtained maximizers saturate the upper bounds in the estimates as the enstrophy increases. In addition, nontrivial be...

  10. Circadian cycles in growth and feeding rates of heterotrophic protist plankton

    DEFF Research Database (Denmark)

    Jakobsen, Hans Henrik; Strom, S.L.

    2004-01-01

    comatum, no day-night difference in growth and feeding rates was found. Maintenance of day-night rate differences during 24-h exposures to continuous darkness demonstrated that most of these protists had circadian cycles. The heterotrophic dinoflagellate Oxyrrhis marina exhibited a clear irradiance...... threshold for maintenance of the circadian cycle: day-night differences in growth and feeding rates were observed at irradiances as low as 2.6 X 10(-3) mumol photons m(-2) s(-1) but not at 3.1 X 10(-4) mumol photons m(-2) s(-1). We also studied growth and feeding in transition from complete darkness...... to culturing in a day: night light cycle in O. marina and found that resetting the circadian cycle in this dinoflagellate temporarily arrested growth and feeding. We suggest that protists use a time-integrated light threshold rather than an instantaneous irradiance to maintain the circadian cell cycle...

  11. Model of apparent crystal growth rate and kinetics of seeded precipitation from sodium aluminate solution

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-bin; LIU Zhi-jian; XU Xiao-hui; ZHOU Qiu-sheng; PENG Zhi-hong; LIU Gui-hua

    2005-01-01

    Based on the population balance equation in a batch crystallizer characteristic of seeded precipitation, a model to calculate the rate of apparent crystal growth of aluminum hydroxide from the size distribution was deve-loped. The simulation results indicate that the rate of apparent crystal growth during seeded precipitation exhibits a manifest dependence on the crystal size. In general, there is an obvious increase in the apparent crystal growth rate with the augment in crystal size. The apparent activation energy increases with the increase of characteristic crystal size, which indicates that the growth of small crystals is controlled by surface chemical reaction; it is gradually controlled by both the surface reaction and diffusion with the augment in crystal size.

  12. Environmental implications of growth rate changes in Montastrea Annularis: Biscayne National Park, Florida

    Science.gov (United States)

    Hudson, J. Harold; Hanson, Kirby J.; Halley, Robert B.; Kindinger, Jack G.

    1994-01-01

    Long-term annual growth rates were determined for 25 Montastrea annularis colonies at eight reef sites in Biscayne National Park, Florida. X-radiographs of slabbed coral cores revealed chronologies that averaged 113.5 years in length with a range of 40 to 242 years. A total of 2,837 annual growth increments were identified and measured. Dating of density bands was verified by visually crossdating fluorescent bands within the coral skeleton. Average accretion rates of individual colonies varied from 5.0 mm·yr−1 in the northernmost sector of the Park to 11.3 mm·yr−1 in the southernmost sector. Long-term growth rates of most corals in this study were greatest prior to about 1950 except for a major, 3–5 year, decline in the growth record of older corals centered around 1878. Waxing and waning coral growth rates are discussed in relation to natural and anthropogenic perturbations that impact this high latitude reef ecosystem. Attention is drawn to nutrients from sewage outfalls as a possible contributing factor to observed growth rate decline since 1950.

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

    Science.gov (United States)

    Dexter, Troy A; Kowalewski, Michał

    2013-12-01

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

  14. Late Pleistocene voles (Arvicolinae, Rodentia) from the Baranica Cave (Serbia)

    Science.gov (United States)

    Bogićević, Katarina; Nenadić, Draženko; Mihailović, Dušan

    2012-02-01

    Baranica is a cave system situated in the south-eastern part of Serbia, four kilometers south to Knjaževac, on the right bank of the Trgovi\\vski Timok. The investigations in Baranica were conducted from 1994 to 1997 by the Faculty of Philosophy from Belgrade and the National Museum of Knjaževac. Four geological layers of Quaternary age were recovered. The abundance of remains of both large and small mammals was noticed in the early phase of the research. In this paper, the remains of eight vole species are described: Arvicola terrestris (Linnaeus, 1758), Chionomys nivalis (Martins, 1842), Microtus (Microtus) arvalis (Pallas, 1778) and Microtus (Microtus) agrestis (Linnaeus, 1761), Microtus (Stenocranius) gregalis (Pallas, 1779), Microtus (Terricola) subterraneus (de Sélys-Longchamps, 1836), Clethrionomys glareolus (Schreber, 1780) and Lagurus lagurus (Pallas, 1773). Among them, steppe and open area inhabitants prevail. Based on the evolutionary level and dimensions of the Arvicola terrestris molars, as well as the overall characteristics of the fauna, it was concluded that the deposits were formed in the last glacial period of the Late Pleistocene. These conclusions are rather consistent with the absolute dating of large mammal bones (23.520 ± 110 B.P. for Layer 2 and 35.780 ± 320 B.P. for Layer 4).

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

    DEFF Research Database (Denmark)

    Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

    2014-01-01

    to age-structured populations. Here we generalize this result to populations structured by stage and age by providing a new, unique measure of reproductive timing (Tc) that, along with net reproductive rate (R0), has a direct mathematical relationship to and approximates growth rate (r). We use simple...

  16. Hydrogen Isotope Effect on the Fatigue Crack Growth Rate in Pipeline Steel

    Science.gov (United States)

    Connolly, Matthew; Slifka, Andrew; Drexler, Elizabeth; Hydrogen Pipeline Safety Team

    Hydrogen (H2) is desirable for energy storage as it is cleaner burning and can store a larger amount of energy than an equal mass of gasoline. One problem in the development of a hydrogen economy is to find or develop materials that ensure the safe, reliable, and cost-effective flow of energy from the source to the user. It is expected steels will be needed to serve this function. However, the existing network of natural gas pipeline, for example, is constructed of ferrous materials which are susceptible to embrittlement and subsequent increased fatigue crack growth rates after exposure to hydrogen. It is expected that diffusion rates play an important role on fatigue crack growth rates. We report the measurement of the fatigue crack growth rate in a high strength pipeline steel in a gaseous deuterium (D2) environment, in an effort to determine the role of diffusion rate on FCGR, because D2 is chemically identical to H2, but with twice the mass. We found that the D2 fatigue crack growth rate was not enhanced compared to air as is seen in an H2 environment; in fact our D2 rate measurement was slightly slower than in air, a result which is not expected to be due to diffusion rates alone. NIST Materials Measurement Laboratory, Applied Chemicals and Materials Division.

  17. Effects of light intensity and temperature on Cryptomonas ovata (Cryptophyceae) growth and nutrient uptake rates

    Science.gov (United States)

    Cloern, James E.

    1977-01-01

    Specific growth rate of Cryptomonas ovata var. palustris Pringsheim was measured in batch culture at 14 light-temperature combinations. Both the maximum growth rate (μm) and optimum light intensity (Iopt) fit an empirical function that increases exponentially with temperature up to an optimum (Topt), then declines rapidly as temperature exceeds Topt. Incorporation of these functions into Steele's growth equation gives a good estimate of specific growth rate over a wide range of temperature and light intensity. Rates of phosphate, ammonium and nitrate uptake were measured separately at 16 combinations of irradiance and temperature and following a spike addition of all starved cells initially took up nutrient at a rapid rate. This transitory surge was followed by a period of steady, substrate-saturated uptake that persisted until external nutrient concentration fell. Substrate-saturated NO3−-uptake proceeded at very slow rates in the dark and was stimulated by both increased temperature and irradiance; NH4+-uptake apparently proceeded at a basal rate at 8 and l4 C and was also stimulated by increased temperature and irradiance. Rates of NH4−-uptake were much higher than NO3−-uptake at all light-temperature combinations. Below 20 C, PO4−3-uptake was more rapid in dark than in light, but was light enhanced at 26 C.

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kay, Steve A. [University of California San Diego

    2013-05-02

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

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

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  1. Maximum growth rate of Mycobacterium avium in continuous culture or chronically infected BALB/c mice.

    Science.gov (United States)

    McCarthy, C M; Taylor, M A; Dennis, M W

    1987-01-01

    Mycobacterium avium is a human pathogen which may cause either chronic or disseminated disease and the organism exhibits a slow rate of growth. This study provides information on the growth rate of the organism in chronically infected mice and its maximal growth rate in vitro. M. avium was grown in continuous culture, limited for nitrogen with 0.5 mM ammonium chloride and dilution rates that ranged from 0.054 to 0.153 h-1. The steady-state concentration of ammonia nitrogen and M. avium cells for each dilution rate were determined. The bacterial saturation constant for growth-limiting ammonia was 0.29 mM (4 micrograms nitrogen/ml) and, from this, the maximal growth rate for M. avium was estimated to be 0.206 h-1 or a doubling time of 3.4 h. BALB/c mice were infected intravenously with 3 x 10(6) colony-forming units and a chronic infection resulted, typical of virulent M. avium strains. During a period of 3 months, the number of mycobacteria remained constant in the lungs, but increased 30-fold and 8,900-fold, respectively, in the spleen and mesenteric lymph nodes. The latter increase appeared to be due to proliferation in situ. The generation time of M. avium in the mesenteric lymph nodes was estimated to be 7 days.

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

    Directory of Open Access Journals (Sweden)

    Oreiro José Luis

    2015-01-01

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

  3. Vole Population Fluctuations: Why and When?%田鼠种群波动的原因和时间

    Institute of Scientific and Technical Information of China (English)

    Lowell L. Getz

    2005-01-01

    densities of population fluctuations of both species. Stoppage of growth of populations of M. ochrogaster resulted from decreased survival, whereas stoppage of most population fluctuations of M. pennsylvanicus resulted from decreased reproduction. Variation in mortality associated with initiation of a population fluctuation is presumed to result primarily from the net effect of a consortium of generalist predators, populations of each which are controlled by factors other than vole densities. Accordingly, predation pressure on vole populations a given year is presumed to be unpredictable, resulting in the observed erratic nature of population fluctuations of M. ochrogaster and M. pennsylvanicus.

  4. Estimating blue whale skin isotopic incorporation rates and baleen growth rates: Implications for assessing diet and movement patterns in mysticetes

    Science.gov (United States)

    Busquets-Vass, Geraldine; Newsome, Seth D.; Calambokidis, John; Serra-Valente, Gabriela; Jacobsen, Jeff K.; Aguíñiga-García, Sergio; Gendron, Diane

    2017-01-01

    Stable isotope analysis in mysticete skin and baleen plates has been repeatedly used to assess diet and movement patterns. Accurate interpretation of isotope data depends on understanding isotopic incorporation rates for metabolically active tissues and growth rates for metabolically inert tissues. The aim of this research was to estimate isotopic incorporation rates in blue whale skin and baleen growth rates by using natural gradients in baseline isotope values between oceanic regions. Nitrogen (δ15N) and carbon (δ13C) isotope values of blue whale skin and potential prey were analyzed from three foraging zones (Gulf of California, California Current System, and Costa Rica Dome) in the northeast Pacific from 1996–2015. We also measured δ15N and δ13C values along the lengths of baleen plates collected from six blue whales stranded in the 1980s and 2000s. Skin was separated into three strata: basale, externum, and sloughed skin. A mean (±SD) skin isotopic incorporation rate of 163±91 days was estimated by fitting a generalized additive model of the seasonal trend in δ15N values of skin strata collected in the Gulf of California and the California Current System. A mean (±SD) baleen growth rate of 15.5±2.2 cm y-1 was estimated by using seasonal oscillations in δ15N values from three whales. These oscillations also showed that individual whales have a high fidelity to distinct foraging zones in the northeast Pacific across years. The absence of oscillations in δ15N values of baleen sub-samples from three male whales suggests these individuals remained within a specific zone for several years prior to death. δ13C values of both whale tissues (skin and baleen) and potential prey were not distinct among foraging zones. Our results highlight the importance of considering tissue isotopic incorporation and growth rates when studying migratory mysticetes and provide new insights into the individual movement strategies of blue whales. PMID:28562625

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-15

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

  6. Cholinesterase inhibition in meadow voles Microtus pennsylvanicus following field applications of Orthene

    Science.gov (United States)

    Jett, D.A.

    1986-01-01

    Brain acetylcholinesterase activity in field-caught meadow voles (Microtus pennsylvanicus) was depressed after a field-spray of Orthene (acephate: acetylphosphoramidothioic acid O,S-dimethyl ester) by as much as 32% in 1982 and 38% in 1983. Short-term recovery was demonstrated and occurred in a time-dependent fashion in 1982. Plasma cholinesterase levels were move variable but also were depressed. Residues were detected in vegetation samples and in the gastrointestinal tracts of exposed voles. Residues in vegetation were diluted or absent 7 to 8 d following the treatment.

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

    Institute of Scientific and Technical Information of China (English)

    Shi Qi; Zhang Yechun; Sun Donghuai

    2003-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Shan Goh

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

  9. Shape of Growth Rate Distribution determines the type of Non-Gibrat's Law

    CERN Document Server

    Ishikawa, Atushi; Mizuno, Takayuki

    2010-01-01

    In this study, by employing exhaustive business data on Japanese firms that approximately fully cover the middle- and large-scale ranges in terms of firm size, the authors confirm the following findings. Detailed Balance is observed not only in profits data but also in sales data. The growth-rate distribution of sales has wider tails than the linear growth-rate distribution of profits in log-log scale. On one hand, in the middle-scale range of profits, the probability of positive growth decreases and the probability of negative growth increases symmetrically as the initial value increases. This is called Non-Gibrat's First Law. On the other hand, in the middle-scale range of sales, the probability of positive growth decreases as the initial value increases, while the probability of negative growth hardly changes. This is called Non-Gibrat's Second Law. Under Detailed Balance, Non-Gibrat's First and Second Laws are analytically induced from the linear and quadratic growth-rate distributions in log-log scale, r...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-02-15

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

  11. Pretreatment Growth Rate Predicts Radiation Response in Vestibular Schwannomas

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-01

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

  12. Lifespan, growth rate, and body size across latitude in marine Bivalvia, with implications for Phanerozoic evolution.

    Science.gov (United States)

    Moss, David K; Ivany, Linda C; Judd, Emily J; Cummings, Patrick W; Bearden, Claire E; Kim, Woo-Jun; Artruc, Emily G; Driscoll, Jeremy R

    2016-08-17

    Mean body size in marine animals has increased more than 100-fold since the Cambrian, a discovery that brings to attention the key life-history parameters of lifespan and growth rate that ultimately determine size. Variation in these parameters is not well understood on the planet today, much less in deep time. Here, we present a new global database of maximum reported lifespan and shell growth coupled with body size data for 1 148 populations of marine bivalves and show that (i) lifespan increases, and growth rate decreases, with latitude, both across the group as a whole and within well-sampled species, (ii) growth rate, and hence metabolic rate, correlates inversely with lifespan, and (iii) opposing trends in lifespan and growth combined with high variance obviate any demonstrable pattern in body size with latitude. Our observations suggest that the proposed increase in metabolic activity and demonstrated increase in body size of organisms over the Phanerozoic should be accompanied by a concomitant shift towards faster growth and/or shorter lifespan in marine bivalves. This prediction, testable from the fossil record, may help to explain one of the more fundamental patterns in the evolutionary and ecological history of animal life on this planet.

  13. Human disturbance influences reproductive success and growth rate in California sea lions (Zalophus californianus).

    Science.gov (United States)

    French, Susannah S; González-Suárez, Manuela; Young, Julie K; Durham, Susan; Gerber, Leah R

    2011-03-16

    The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations.

  14. Human disturbance influences reproductive success and growth rate in California sea lions (Zalophus californianus.

    Directory of Open Access Journals (Sweden)

    Susannah S French

    Full Text Available The environment is currently undergoing changes at both global (e.g., climate change and local (e.g., tourism, pollution, habitat modification scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups for California sea lions (Zalophus californianus in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources. Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations.

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Aniefiok Akpan Umoren

    2016-04-01

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

  17. Size evolution in microorganisms masks trade-offs predicted by the growth rate hypothesis.

    Science.gov (United States)

    Gounand, Isabelle; Daufresne, Tanguy; Gravel, Dominique; Bouvier, Corinne; Bouvier, Thierry; Combe, Marine; Gougat-Barbera, Claire; Poly, Franck; Torres-Barceló, Clara; Mouquet, Nicolas

    2016-12-28

    Adaptation to local resource availability depends on responses in growth rate and nutrient acquisition. The growth rate hypothesis (GRH) suggests that growing fast should impair competitive abilities for phosphorus and nitrogen due to high demand for biosynthesis. However, in microorganisms, size influences both growth and uptake rates, which may mask trade-offs and instead generate a positive relationship between these traits (size hypothesis, SH). Here, we evolved a gradient of maximum growth rate (μmax) from a single bacterium ancestor to test the relationship among μmax, competitive ability for nutrients and cell size, while controlling for evolutionary history. We found a strong positive correlation between μmax and competitive ability for phosphorus, associated with a trade-off between μmax and cell size: strains selected for high μmax were smaller and better competitors for phosphorus. Our results strongly support the SH, while the trade-offs expected under GRH were not apparent. Beyond plasticity, unicellular populations can respond rapidly to selection pressure through joint evolution of their size and maximum growth rate. Our study stresses that physiological links between these traits tightly shape the evolution of competitive strategies.

  18. Inbreeding avoidance drives consistent variation of fine-scale genetic structure caused by dispersal in the seasonal mating system of Brandt's voles.

    Directory of Open Access Journals (Sweden)

    Xiao Hui Liu

    Full Text Available Inbreeding depression is a major evolutionary and ecological force influencing population dynamics and the evolution of inbreeding-avoidance traits such as mating systems and dispersal. Mating systems and dispersal are fundamental determinants of population genetic structure. Resolving the relationships among genetic structure, seasonal breeding-related mating systems and dispersal will facilitate our understanding of the evolution of inbreeding avoidance. The goals of this study were as follows: (i to determine whether females actively avoided mating with relatives in a group-living rodent species, Brandt's voles (Lasiopodomys brandtii, by combined analysis of their mating system, dispersal and genetic structure; and (ii to analyze the relationships among the variation in fine-genetic structure, inbreeding avoidance, season-dependent mating strategies and individual dispersal. Using both individual- and population-level analyses, we found that the majority of Brandt's vole groups consisted of close relatives. However, both group-specific FISs, an inbreeding coefficient that expresses the expected percentage rate of homozygosity arising from a given breeding system, and relatedness of mates showed no sign of inbreeding. Using group pedigrees and paternity analysis, we show that the mating system of Brandt's voles consists of a type of polygyny for males and extra-group polyandry for females, which may decrease inbreeding by increasing the frequency of mating among distantly-related individuals. The consistent variation in within-group relatedness, among-group relatedness and fine-scale genetic structures was mostly due to dispersal, which primarily occurred during the breeding season. Biologically relevant variation in the fine-scale genetic structure suggests that dispersal during the mating season may be a strategy to avoid inbreeding and drive the polygynous and extra-group polyandrous mating system of this species.

  19. The effect of material properties on growth rates of folding and boudinage: Experiments with wax models

    Science.gov (United States)

    Neurath, C.; Smith, R. B.

    The growth of unstable structures was studied experimentally in layered wax models. The rheological properties of the two wax types were determined independently by a series of cylinder compression tests. Both waxes enhibited (1) a non-Newtonian stress vs strain-rate relationship (2) strain softening and (3) temperature-dependent viscosity. The stress-strain-rate relationships approximated a power-law, with stress exponents of 5 for the microcrystalline wax and 1.8 for paraffin wax. Blocks of paraffin with a single embedded layer of microcrystalline wax were deformed in two-dimensional pure shear with the layer oriented either parallel to the compressive strain axis so that it shortened and folded, or perpendicular to that axis so that it would stretch and boundinage would form. The growth rates of tiny initial disturbances were measured. The growth rates for folding and boudinage were much higher than could be accounted for by theories assuming Newtonian material properties. Theories taking non-Newtonian behaviour into account (Smith, R. B. 1975. Bull. geol. Soc. Am.86, 1601-1609; Fletcher, R. C. 1974. Am. J. Sci.274, 1029-1043) better describe the folding growth rates. Boudinage, however, grew almost three times faster than would be predicted even by existing non-Newtonian theory. A possible reason for this discrepancy is that the waxes do not exhibit steady-state creep as assumed in the theory. We, therefore, extend the theory to include strain-softening. The crucial step in this theory is the use of a scalar measure of the deformation as a state variable in the constitutive law. In this way the isotropic manifestation of strain-softening can be taken into account. The analysis shows that strain-softening can lead to greatly increased boudinage growth rates while having little influence on the growth rates of folds, which is in agreement with the experiments.

  20. Implications Of Foreign Direct Investment, Financial Development And Real Exchange Rate For Economic Growth In Cameroon

    Directory of Open Access Journals (Sweden)

    Victalice Ngimanang Achamoh

    2016-05-01

    Full Text Available This paper assesses the effects of foreign direct investment (FDI, financial development and real exchange rate (RER on economic growth in Cameroon using Cameroon’s annual time series data spanning the period 1977 - 2010. To address these objectives, residual based Engle-Granger test, the OLS based Autoregressive Distributive Lag (ARDL bound testing and maximum likelihood based Johansen cointegration techniques are employed. Results of Unit roots tests show that all the series possessed unit roots at level or first difference form. The ARDL model and VECM results reveal that the RER has a significant negative effect on economic growth, while FDI and Financial Development relate positively to economic growth. These findings have implications for stimulating economic growth by increasing efficiency of the financial sector in allocating credit to the private sector and preventing real exchange rate appreciation in the shortrun.

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

    Directory of Open Access Journals (Sweden)

    Perrette Yves

    2010-07-01

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

  2. Fatigue Crack Growth Rate of Inconel 718 Sheet at Cryogenic Temperatures

    Science.gov (United States)

    Wells, Douglas; Wright, Jonathan; Hastings, Keith

    2005-01-01

    Inconel 718 sheet material was tested to determine fatigue crack growth rate (FCGR) at cryogenic conditions representative of a liquid hydrogen (LH2) environment at -423 degree F. Tests utilized M(T) and ESE(T) specimen geometries and environments were either cold gaseous helium or submersion in LH2. The test results support a significant improvement in the fatigue crack growth threshold at -423 degree F compared to -320 degree F or 70 degree F.

  3. DETERMINANTS OF GROWTH RATE: SOME METHODOLOGICAL ISSUES WITH DATA FROM FIJI

    OpenAIRE

    Bhaskara Rao; Maheshwar Rao

    2005-01-01

    Compared to many cross-country studies on the determinants of growth rate, time series approaches are relatively few and limited in scope. However, time series studies are useful for country-specific policies. But in many recent works ad hoc specifications have been used to analyze the contribution of various factors to growth. This paper examines the specification and estimation issues in the time series approach and provides some guidelines. Our approach is used to illustrate the effects of...

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

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

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

  5. Maximising electricity production by controlling the biofilm specific growth rate in microbial fuel cells.

    Science.gov (United States)

    Ledezma, Pablo; Greenman, John; Ieropoulos, Ioannis

    2012-08-01

    The aim of this work is to study the relationship between growth rate and electricity production in perfusion-electrode microbial fuel cells (MFCs), across a wide range of flow rates by co-measurement of electrical output and changes in population numbers by viable counts and optical density. The experiments hereby presented demonstrate, for the first time to the authors' knowledge, that the anodic biofilm specific growth rate can be determined and controlled in common with other loose matrix perfusion systems. Feeding with nutrient-limiting conditions at a critical flow rate (50.8 mL h(-1)) resulted in the first experimental determination of maximum specific growth rate μ(max) (19.8 day(-1)) for Shewanella spp. MFC biofilms, which is considerably higher than those predicted or assumed via mathematical modelling. It is also shown that, under carbon-energy limiting conditions there is a strong direct relationship between growth rate and electrical power output, with μ(max) coinciding with maximum electrical power production.

  6. Differential effect of culture temperature and specific growth rate on CHO cell behavior in chemostat culture.

    Science.gov (United States)

    Vergara, Mauricio; Becerra, Silvana; Berrios, Julio; Osses, Nelson; Reyes, Juan; Rodríguez-Moyá, María; Gonzalez, Ramon; Altamirano, Claudia

    2014-01-01

    Mild hypothermia condition in mammalian cell culture technology has been one of the main focuses of research for the development of breeding strategies to maximize productivity of these production systems. Despite the large number of studies that show positive effects of mild hypothermia on specific productivity of r-proteins, no experimental approach has addressed the indirect effect of lower temperatures on specific cell growth rate, nor how this condition possibly affects less specific productivity of r-proteins. To separately analyze the effects of mild hypothermia and specific growth rate on CHO cell metabolism and recombinant human tissue plasminogen activator productivity as a model system, high dilution rate (0.017 h(-1)) and low dilution rate (0.012 h(-1)) at two cultivation temperatures (37 and 33 °C) were evaluated using chemostat culture. The results showed a positive effect on the specific productivity of r-protein with decreasing specific growth rate at 33 °C. Differential effect was achieved by mild hypothermia on the specific productivity of r-protein, contrary to the evidence reported in batch culture. Interestingly, reduction of metabolism could not be associated with a decrease in culture temperature, but rather with a decrease in specific growth rate.

  7. A new mechanistic growth model for simultaneous determination of lag phase duration and exponential growth rate and a new Bĕlehdrádek-type model for evaluating the effect of temperature on growth rate.

    Science.gov (United States)

    Huang, Lihan

    2011-06-01

    A new mechanistic growth model was developed to describe microbial growth under isothermal conditions. The new mathematical model was derived from the basic observation of bacterial growth that may include lag, exponential, and stationary phases. With this model, the lag phase duration and exponential growth rate of a growth curve were simultaneously determined by nonlinear regression. The new model was validated using Listeria monocytogenes and Escherichia coli O157:H7 in broth or meat. Statistical results suggested that both bias factor (B(f)) and accuracy factor (A(f)) of the new model were very close to 1.0. A new Bĕlehdrádek-type rate model and the Ratkowsky square-root model were used to describe the temperature dependence of bacterial growth rate. It was observed that the maximum and minimum temperatures were more accurately estimated by a new Bĕlehdrádek-type rate model. Further, the inverse of square-roots of lag phases was found proportional to temperature, making it possible to estimate the lag phase duration from the growth temperature.

  8. INTEREST RATE, YIELD SPREAD AND ECONOMIC GROWTH: THE CASE OF TURKEY (1990-2006

    Directory of Open Access Journals (Sweden)

    RAHMİ YAMAK

    2013-06-01

    Full Text Available In the literature, the difference between short-term interest rate and long-term interest rate is defined as yield spread or as the slope of the yield curve. The purpose of this study is to test whether yield spread affects the future economic growth for Turkey. For this purpose, in the empircal section of the study, quarterly real gross domestic product and the 3-month and 12-month interest rates are included into the analysis. Inflation rate as the control variable is included into the regressions to increase the validity of the findings. In addition, changes in the GDP are tried to be explained not only by yield spread but also by the level of the interest rates. The main purpose of this inclusion is to determine whether yield spread or interest rate level is effective in forecasting the changes of growth rates. Acording to the findings of the study, in Turkey both yield spread and interest rates affect the future economic growth .

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

    Science.gov (United States)

    Reddy, Michael M.

    2012-08-01

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

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

    Science.gov (United States)

    Reddy, Michael M.

    2012-01-01

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

  11. Understanding contributions of cohort effects to growth rates of fluctuating populations.

    Science.gov (United States)

    Wittmer, Heiko U; Powell, Roger A; King, Carolyn M

    2007-09-01

    1. Understanding contributions of cohort effects to variation in population growth of fluctuating populations is of great interest in evolutionary biology and may be critical in contributing towards wildlife and conservation management. Cohort-specific contributions to population growth can be evaluated using age-specific matrix models and associated elasticity analyses. 2. We developed age-specific matrix models for naturally fluctuating populations of stoats Mustela erminea in New Zealand beech forests. Dynamics and productivity of stoat populations in this environment are related to the 3-5 year masting cycle of beech trees and consequent effects on the abundance of rodents. 3. The finite rate of increase (lambda) of stoat populations in New Zealand beech forests varied substantially, from 1.98 during seedfall years to 0.58 during post-seedfall years. Predicted mean growth rates for stoat populations in continuous 3-, 4- or 5-year cycles are 0.85, 1.00 and 1.13. The variation in population growth was a consequence of high reproductive success of females during seedfall years combined with low survival and fertility of females of the post-seedfall cohort. 4. Variation in population growth was consistently more sensitive to changes in survival rates both when each matrix was evaluated in isolation and when matrices were linked into cycles. Relative contributions to variation in population growth from survival and fertility, especially in 0-1-year-old stoats, also depend on the year of the cycle and the number of transitional years before a new cycle is initiated. 5. Consequently, management strategies aimed at reducing stoat populations that may be best during one phase of the beech seedfall cycle may not be the most efficient during other phases of the cycle. We suggest that management strategies based on elasticities of vital rates need to consider how population growth rates vary so as to meet appropriate economic and conservation targets.

  12. Estimating Nursing Wage Bill in Canada and Breaking Down the Growth Rate: 2000 to 2010.

    Science.gov (United States)

    Ariste, Ruolz; Béjaoui, Ali

    2015-05-01

    Even though the nursing professional category (registered nurses [RNs] and licensed practical nurses) made up about one-third of the Canadian health professionals, no study exists about their wage bill, the composition and growth rate of this wage bill. This paper attempts to fill this gap by estimating the nursing wage bill in the Canadian provinces and breaking down the growth rate for the 2000-2010 period, using the 2001 Census and the 2011 National Household Survey. Total wage bill for the nursing professional category in Canada was estimated at $20.1 billion ($17.3 billion for RNs), which suggests that it is as substantial as net physician remuneration. The average annual growth rate of this wage bill was 6.6% for RNs. This increase was mainly driven by real (inflation-adjusted) wage per hour, which was 3.0%, suggesting the existence of a "health premium" of 1.7 percentage points during the study period.

  13. THE EFFECT OF FEEDING Lactobacillus ON GROWTH, SURVIVAL RATE AND PROTEASE ACTIVITY OF Litopenaeus vannamei

    Directory of Open Access Journals (Sweden)

    Nunak Nafiqoh

    2011-12-01

    Full Text Available This study examined the effect of two Lactobacillus bacteria on protease activity and growth rate of Litopenaeus vannamei. An experiment was conducted to examine protease activity and growth rate. The experiment consisted of two treatment tanks, the first tank was provided with artemia immersed in 2.6 x 1016 cfu/mL of bacteria solution, the second tank served as the control tank. After 20 days, the L. vannamei in the tank that received Lactobacillus have significantly different in growth, survival rate and protease activity (P<0.05 compared to the control, but no significant difference between Lactobacillus casei and Lactobacillus plantarum treatments. Within the digestive organ, protease activity of hepatopancreas and stomach demonstrated significant higher activity (P<0.05 compared to the intestine.

  14. Causality Relationship Between Import, Export and Growth Rate in Developing Countries

    Directory of Open Access Journals (Sweden)

    Serhat YUKSEL

    2017-06-01

    Full Text Available In this paper, we tried to determine the relationship between imports, exports and growth rate in developing countries. Within this scope, 6 developing countries (Argentina, Brazil, China, Malaysia, Mexico and Turkey were analyzed in this study. In order to achieve this purpose, annual data for the periods between 1961 and 2014 was tested by using Engle Granger co-integration analysis, Vector Error Correction Model and Toda Yamamoto causality analysis. According to the result of the analysis, it was determined that there is not any relationship among three variables in Brazil and Mexico. On the other hand, we defined that increase in export causes higher growth rate in Argentina. Moreover, it was concluded that there is a causal relationship from import to export in China and Turkey. Furthermore, it was determined that export causes higher import in Malaysia. Therefore, it can be concluded that the relationship between import, export and growth rate is not same for all developing countries..

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

    Directory of Open Access Journals (Sweden)

    Long Cheng

    2016-07-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  17. Maximum Likelihood based comparison of the specific growth rates for P. aeruginosa and four mutator strains

    DEFF Research Database (Denmark)

    Philipsen, Kirsten Riber; Christiansen, Lasse Engbo; Mandsberg, Lotte Frigaard

    2008-01-01

    that best describes data is a model taking into account the full covariance structure. An inference study is made in order to determine whether the growth rate of the five bacteria strains is the same. After applying a likelihood-ratio test to models with a full covariance structure, it is concluded...... that the specific growth rate is the same for all bacteria strains. This study highlights the importance of carrying out an explorative examination of residuals in order to make a correct parametrization of a model including the covariance structure. The ML method is shown to be a strong tool as it enables......The specific growth rate for P. aeruginosa and four mutator strains mutT, mutY, mutM and mutY–mutM is estimated by a suggested Maximum Likelihood, ML, method which takes the autocorrelation of the observation into account. For each bacteria strain, six wells of optical density, OD, measurements...

  18. Weibel Instability Growth Rate in Magnetized Plasmas with Quasi-Relativistic Distribution Function

    Science.gov (United States)

    Hosseini, Sayed Ahmad; Mahdavi, Mohammad

    2016-12-01

    The mechanism of the Weibel instability is investigated for dense magnetized plasmas. As we know, due to the electron velocity distribution, the Coulomb collision effect of electron-ion and the relativistic properties play an important role in such study. In this study an analytical expression for the growth rate and the condition of restricting the Weibel instability are derived for low-frequency limit. These calculations are done for the oscillation frequency dependence on the electron cyclotron frequency. It is shown that, the relativistic properties of the particle lead to increasing the growth rate of the instability. On the other hand the collision effects and background magnetic field try to decrease the growth rate by decreasing the temperature anisotropy and restricting the particles movement.

  19. Maximum initial growth-rate of strong-shock-driven Richtmyer-Meshkov instability

    Science.gov (United States)

    Dell, Z. R.; Pandian, A.; Bhowmick, A. K.; Swisher, N. C.; Stanic, M.; Stellingwerf, R. F.; Abarzhi, S. I.

    2017-09-01

    We focus on the classical problem of the dependence on the initial conditions of the initial growth-rate of strong shock driven Richtmyer-Meshkov instability (RMI) by developing a novel empirical model and by employing rigorous theories and Smoothed Particle Hydrodynamics simulations to describe the simulation data with statistical confidence in a broad parameter regime. For the given values of the shock strength, fluid density ratio, and wavelength of the initial perturbation of the fluid interface, we find the maximum value of the RMI initial growth-rate, the corresponding amplitude scale of the initial perturbation, and the maximum fraction of interfacial energy. This amplitude scale is independent of the shock strength and density ratio and is characteristic quantity of RMI dynamics. We discover the exponential decay of the ratio of the initial and linear growth-rates of RMI with the initial perturbation amplitude that excellently agrees with available data.

  20. The Balance of Payments Constraint as an Explanation of International Growth Rate Differences

    Directory of Open Access Journals (Sweden)

    Anthony P. Thirlwall

    2011-12-01

    Full Text Available The paper shows that if long-run balance of payments equilibrium on current account is a requirement then a country's long run growth rate can be approximated by the ratio of the growth of exports to the income elasticity of demand for imports. The model fits well the experience of eighteen OECD countries. It is output, not relative prices, that adjusts the balance of payments, contrary to the neoclassical orthodoxy. Growth can be demand constained by the balance of payments.

  1. Growth rates, seed size, and physiology: do small-seeded species really grow faster?

    Science.gov (United States)

    Turnbull, Lindsay A; Paul-Victor, Cloé; Schmid, Bernhard; Purves, Drew W

    2008-05-01

    Relative growth rate (RGR) is currently the most commonly used method for measuring and comparing species' intrinsic growth potential. Comparative studies have, for example, revealed that small-seeded species have higher RGR, leading to the common belief that small-seeded species possess physiological adaptations for rapid growth that would allow them to outgrow large-seeded species, given sufficient time. We show that, because RGR declines as individual plants grow, it is heavily biased by initial size and does not measure the size-corrected growth potential that determines the outcome of competition in the long-term. We develop a daily growth model that includes a simple mechanistic representation of aboveground and belowground growth and its dependency on plant size and environmental factors. Intrinsic growth potential is encapsulated by the size-independent growth coefficient, G. We parameterized the model using repeated-harvest data from 1724 plants of nine species growing in contrasting nutrient and temperature regimes. Using information-theoretic criteria, we found evidence for interspecific differences in only three of nine model parameters: G, aboveground allocation, and frost damage. With other parameters shared between species, the model accurately reproduced above- and belowground biomass trajectories for all nine species in each set of environmental conditions. In contrast to conventional wisdom, the relationship between G and seed size was positive, despite a strong negative correlation between seed size and average RGR, meaning that large-seeded rather than small-seeded species have higher size-corrected growth potential. Further, we found a significant positive correlation between G and frost damage that, according to simulations, causes rank reversals in final biomass under daily temperature changes of +/- 5 degrees C. We recommend the wider use of this new kind of plant growth analysis as a better way of understanding underlying differences in

  2. Distribution of linear growth rates in different directions in root apical meristems

    Directory of Open Access Journals (Sweden)

    Jerzy Nakielski

    2014-01-01

    Full Text Available Growth of apical meristems in plants may be well described by the growth tensor method. Hejnowicz (Envir. Exp. Bot. 1989, 29 determined growth tensors for roots: one with a minimum and the other with a maximum of the relative elemental growth rate in volume and used them for the description of two types of apices: one with an apical cell and merophytes (I, and the other with files of cells converging towards a quiescent centre, CQ (II. In the present paper the same cases are considered from the point of view of a spatial and directional variation of the relative elemental rate of growth in length, RERG1. Maps of the RERG1 in two planes: axial and tangential, the latter determined by periclinal-longitudinal (PL and periclinal-tangential (PT principal growth directions, are shown. In an apical part of apex i where there is maximum volumetric growth, there also occurs a maximum of RERG1 for all directions. In regions other than this RERG1 decreases although RERG1 in the PL direction predominates everywhere. In apex II RERG1 for all directions has a minimum in CQ and becomes increasingly larger with increasing distance from it - the maximum is in the PL direction in the cylindrical part of the apex. In peripheral parts of both apices, in the place of the root/cap junction, RERG, in the anticlinal direction is significantly small.

  3. Bacterial growth rates are influenced by cellular characteristics of individual species when immersed in electromagnetic fields.

    Science.gov (United States)

    Tessaro, Lucas W E; Murugan, Nirosha J; Persinger, Michael A

    2015-03-01

    Previous studies have shown that exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) have negative effects on the rate of growth of bacteria. In the present study, two Gram-positive and two Gram-negative species were exposed to six magnetic field conditions in broth cultures. Three variations of the 'Thomas' pulsed frequency-modulated pattern; a strong-static "puck" magnet upwards of 5000G in intensity; a pair of these magnets rotating opposite one another at ∼30rpm; and finally a strong dynamic magnetic field generator termed the 'Resonator' with an average intensity of 250μT were used. Growth rate was discerned by optical density (OD) measurements every hour at 600nm. ELF-EMF conditions significantly affected the rates of growth of the bacterial cultures, while the two static magnetic field conditions were not statistically significant. Most interestingly, the 'Resonator' dynamic magnetic field increased the rates of growth of three species (Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli), while slowing the growth of one (Serratia marcescens). We suggest that these effects are due to individual biophysical characteristics of the bacterial species.

  4. Effects of lowered pH on marine phytoplankton growth rates

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  5. Stress-induced martensitic transformation in metastable austenitic stainless steels: Effect on fatigue crack growth rate

    Science.gov (United States)

    Khan, Z.; Ahmed, M.

    1996-04-01

    This paper addresses the influence of cyclic stress-induced martensitic transformation on fatigue crack growth rates in metastable austenitic stainless steels. At low applied stress and mean stress values in AISI type 301 stainless steel, fatigue crack growth rate is substantially retarded due to a cyclic stress-induced γ-α' and γ-ɛ martensitic transformation occurring at the crack-tip plastic zone. It is suggested that the transformation products produce a compressive residual stress at the tip of the fatigue crack, which essentially lowers the effective stress intensity and hence retards the fatigue crack growth rate. At high applied stress or mean stress values, fatigue crack growth rates in AISI type 301 steels become almost equal to those of stable AISI type 302 alloy. As the amount of transformed products increases (with an increase in applied or mean stress), the strain-hardening effect brought about by the transformed martensite phase appears to accelerate fatigue crack growth, offsetting the contribution from the compressive residual stress produced by the positive volume change of γ → α' or ɛ transformation.

  6. Influence of arterial geometry on a model for growth rate of atheromas

    Energy Technology Data Exchange (ETDEWEB)

    Gessaghi, Valeria C [Facultad de Ingenieria, Universidad Nacional de La Pampa, General Pico, La Pampa (Argentina); Raschi, Marcelo A [Facultad de Ingenieria y Ciencias Exactas y Centro de Estudios Avanzados, Universidad Argentina de la Empresa, Ciudad Autonoma de Buenos Aires (Argentina); Larreteguy, Axel E [Facultad de Ingenieria y Ciencias Exactas y Centro de Estudios Avanzados, Universidad Argentina de la Empresa, Ciudad Autonoma de Buenos Aires (Argentina); Perazzo, Carlos A [Facultad de Ingenieria y Ciencias Exactas y Naturales, Universidad de Favaloro, Ciudad Autonoma de Buenos Aires, Argentina y CONICET (Argentina)

    2007-11-15

    Atherosclerosis is a disease that affects medium and large size arteries and it can partially or totally obstruct blood flow through them. The lack of blood supply to the heart or the brain can cause an infarct or a stroke with fatal consequences or permanent effects. This disease involves the proliferation of cells and the accumulation of fat, cholesterol, cell debris, calcium and other substances in the artery wall. Such accumulation results in the formation of atherosclerotic plaques called atheromas, which may cause the obstruction of the blood flow. Cardiovascular diseases, among which atherosclerosis is the most frequent, are the first cause of death in developed countries. The published works in the subject suggest that hemodynamic forces on arterial walls have influence on the localization, initial development and growth rate of atheromas. This paper presents a model for this growth rate, and explores the influence of the bifurcation angle on the blood flow patterns and on the predictions of the model in a simplified carotid artery. The choice of the carotid bifurcation as the subject for this study obeys the fact that atheromas in this artery are often responsible for strokes. Our model predicts a larger initial growth rate in the external walls of the bifurcation and smaller growth area and lower growth rates as the bifurcation angle is increased. The reason for this seems to be the appearance of helical flow patterns as the angle is increased.

  7. Modeling circadian clock-cell cycle interaction effects on cell population growth rates.

    Science.gov (United States)

    El Cheikh, R; Bernard, S; El Khatib, N

    2014-12-21

    The circadian clock and the cell cycle are two tightly coupled oscillators. Recent analytical studies have shown counter-intuitive effects of circadian gating of the cell cycle on growth rates of proliferating cells which cannot be explained by a molecular model or a population model alone. In this work, we present a combined molecular-population model that studies how coupling the circadian clock to the cell cycle, through the protein WEE1, affects a proliferating cell population. We show that the cell cycle can entrain to the circadian clock with different rational period ratios and characterize multiple domains of entrainment. We show that coupling increases the growth rate for autonomous periods of the cell cycle around 24 h and above 48 h. We study the effect of mutation of circadian genes on the growth rate of cells and show that disruption of the circadian clock can lead to abnormal proliferation. Particularly, we show that Cry 1, Cry 2 mutations decrease the growth rate of cells, Per 2 mutation enhances it and Bmal 1 knockout increases it for autonomous periods of the cell cycle less than 21 h and decreases it elsewhere. Combining a molecular model to a population model offers new insight on the influence of the circadian clock on the growth of a cell population. This can help chronotherapy which takes benefits of physiological rhythms to improve anti-cancer efficacy and tolerance to drugs by administering treatments at a specific time of the day.

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

    Science.gov (United States)

    Ewbank, Douglas

    2016-04-19

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

  9. L-harmonic functions with polynomial growth of a fixed rate

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Yau made the following conjecture:For a complete noncompact manifold with nonnegative Ricci curvature the space of harmonic functions with polynomial growth of a fixed rate is finite dimensional.we extend the result on the Laplace operator to that on the symmetric diffusion operator,and prove the space of L-harmonic functions with polynomial growth of a fixed rate is finitedimensional,when m-dimensional Bakery-Emery Ricci curvature of the symmetric diffusion operator on the complete noncompact Riemannian manifold is nonnegative.

  10. L-harmonic functions with polynomial growth of a fixed rate

    Institute of Scientific and Technical Information of China (English)

    ZHOU ChaoHui; CHEN ZhiHua

    2009-01-01

    Yau made the following conjecture: For a complete noncompact manifold with nonnegative Ricci curvature the space of harmonic functions with polynomial growth of a fixed rate is finite dimensional,we extend the result on the Laplace operator to that on the symmetric diffusion operator,and prove the space of L-harmonic functions with polynomial growth of a fixed rate is finitedimensional,when m-dimensional Bakery-Emery Ricci curvature of the symmetric diffusion operator on the complete noncompact Riemannian manifold is nonnegative.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-12

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

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

    Institute of Scientific and Technical Information of China (English)

    Fan Bo-nai; Lai Xiong-xiang

    2006-01-01

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

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

    DEFF Research Database (Denmark)

    2013-01-01

    's adaptation to the environment, with consequently less universal mass scaling properties. Data on body mass, maximum ingestion and clearance rates, respiration rates and maximum growth rates of animals living in the ocean epipelagic were compiled from the literature, mainly from original papers but also from...... previous compilations by other authors. Data were read from tables or digitized from graphs. Only measurements made on individuals of know size, or groups of individuals of similar and known size were included. We show that clearance and respiration rates have life-form-dependent allometries that have...

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

    Directory of Open Access Journals (Sweden)

    Elizabeth M Troyer

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

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

    Directory of Open Access Journals (Sweden)

    Dániel Kozma

    2012-01-01

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

  16. Sex-based differences in Adelie penguin (Pygoscelis adeliae) chick growth rates.

    Science.gov (United States)

    Jennings, Scott; Varsani, Arvind; Dugger, Catherine; Ballard, Grant; Ainley, David G.

    2016-01-01

    Sexually size-dimorphic species must show some difference between the sexes in growth rate and/or length of growing period. Such differences in growth parameters can cause the sexes to be impacted by environmental variability in different ways, and understanding these differences allows a better understanding of patterns in productivity between individuals and populations. We investigated differences in growth rate and diet between male and female Adélie Penguin (Pygoscelis adeliae) chicks during two breeding seasons at Cape Crozier, Ross Island, Antarctica. Adélie Penguins are a slightly dimorphic species, with adult males averaging larger than adult females in mass (~11%) as well as bill (~8%) and flipper length (~3%). We measured mass and length of flipper, bill, tibiotarsus, and foot at 5-day intervals for 45 male and 40 female individually-marked chicks. Chick sex was molecularly determined from feathers. We used linear mixed effects models to estimate daily growth rate as a function of chick sex, while controlling for hatching order, brood size, year, and potential variation in breeding quality between pairs of parents. Accounting for season and hatching order, male chicks gained mass an average of 15.6 g d-1 faster than females. Similarly, growth in bill length was faster for males, and the calculated bill size difference at fledging was similar to that observed in adults. There was no evidence for sex-based differences in growth of other morphological features. Adélie diet at Ross Island is composed almost entirely of two species—one krill (Euphausia crystallorophias) and one fish (Pleuragramma antarctica), with fish having a higher caloric value. Using isotopic analyses of feather samples, we also determined that male chicks were fed a higher proportion of fish than female chicks. The related differences in provisioning and growth rates of male and female offspring provides a greater understanding of the ways in which ecological factors may impact

  17. Morphology and mycelial growth rate of Pleurotus spp. strains from the Mexican mixtec region.

    Science.gov (United States)

    Guadarrama-Mendoza, P C; del Toro, G Valencia; Ramírez-Carrillo, R; Robles-Martínez, F; Yáñez-Fernández, J; Garín-Aguilar, M E; Hernández, C G; Bravo-Villa, G

    2014-01-01

    Two native Pleurotus spp. strains (white LB-050 and pale pink LB-051) were isolated from rotten tree trunks of cazahuate (Ipomoea murucoides) from the Mexican Mixtec Region. Both strains were chemically dedikaryotized to obtain their symmetrical monokaryotic components (neohaplonts). This was achieved employing homogenization time periods from 60 to 65 s, and 3 day incubation at 28 °C in a peptone-glucose solution (PGS). Pairing of compatible neohaplonts resulted in 56 hybrid strains which were classified into the four following hybrid types: (R(1-n)xB(1-n), R(1-n)xB(2-1), R(2-n)xB(1-n) and R(2-n)xB(2-1)). The mycelial growth of Pleurotus spp. monokaryotic and dikaryotic strains showed differences in texture (cottony or floccose), growth (scarce, regular or abundant), density (high, regular or low), and pigmentation (off-white, white or pale pink). To determine the rate and the amount of mycelium growth in malt extract agar at 28 °C, the diameter of the colony was measured every 24 h until the Petri dish was completely colonized. A linear model had the best fit to the mycelial growth kinetics. A direct relationship between mycelial morphology and growth rate was observed. Cottony mycelium presented significantly higher growth rates (p < 0.01) in comparison with floccose mycelium. Thus, mycelial morphology can be used as criterion to select which pairs must be used for optimizing compatible-mating studies. Hybrids resulting from cottony neohaplonts maintained the characteristically high growth rates of their parental strains with the hybrid R(1-n)xB(1-n) being faster than the latter.

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

    Science.gov (United States)

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

    2005-12-01

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

  19. Sex-Based Differences in Adelie Penguin (Pygoscelis adeliae Chick Growth Rates and Diet.

    Directory of Open Access Journals (Sweden)

    Scott Jennings

    Full Text Available Sexually size-dimorphic species must show some difference between the sexes in growth rate and/or length of growing period. Such differences in growth parameters can cause the sexes to be impacted by environmental variability in different ways, and understanding these differences allows a better understanding of patterns in productivity between individuals and populations. We investigated differences in growth rate and diet between male and female Adélie Penguin (Pygoscelis adeliae chicks during two breeding seasons at Cape Crozier, Ross Island, Antarctica. Adélie Penguins are a slightly dimorphic species, with adult males averaging larger than adult females in mass (~11% as well as bill (~8% and flipper length (~3%. We measured mass and length of flipper, bill, tibiotarsus, and foot at 5-day intervals for 45 male and 40 female individually-marked chicks. Chick sex was molecularly determined from feathers. We used linear mixed effects models to estimate daily growth rate as a function of chick sex, while controlling for hatching order, brood size, year, and potential variation in breeding quality between pairs of parents. Accounting for season and hatching order, male chicks gained mass an average of 15.6 g d(-1 faster than females. Similarly, growth in bill length was faster for males, and the calculated bill size difference at fledging was similar to that observed in adults. There was no evidence for sex-based differences in growth of other morphological features. Adélie diet at Ross Island is composed almost entirely of two species--one krill (Euphausia crystallorophias and one fish (Pleuragramma antarctica, with fish having a higher caloric value. Using isotopic analyses of feather samples, we also determined that male chicks were fed a higher proportion of fish than female chicks. The related differences in provisioning and growth rates of male and female offspring provides a greater understanding of the ways in which ecological factors

  20. Morphology and mycelial growth rate of Pleurotus spp. strains from the Mexican mixtec region

    Directory of Open Access Journals (Sweden)

    P.C. Guadarrama-Mendoza

    2014-09-01

    Full Text Available Two native Pleurotus spp. strains (white LB-050 and pale pink LB-051 were isolated from rotten tree trunks of cazahuate (Ipomoea murucoides from the Mexican Mixtec Region. Both strains were chemically dedikaryotized to obtain their symmetrical monokaryotic components (neohaplonts. This was achieved employing homogenization time periods from 60 to 65 s, and 3 day incubation at 28 °C in a peptone-glucose solution (PGS. Pairing of compatible neohaplonts resulted in 56 hybrid strains which were classified into the four following hybrid types: (R1-n xB1-n, R1-n xB2-1, R2-n xB1-n and R2-n xB2-1. The mycelial growth of Pleurotus spp. monokaryotic and dikaryotic strains showed differences in texture (cottony or floccose, growth (scarce, regular or abundant, density (high, regular or low, and pigmentation (off-white, white or pale pink. To determine the rate and the amount of mycelium growth in malt extract agar at 28 °C, the diameter of the colony was measured every 24 h until the Petri dish was completely colonized. A linear model had the best fit to the mycelial growth kinetics. A direct relationship between mycelial morphology and growth rate was observed. Cottony mycelium presented significantly higher growth rates (p < 0.01 in comparison with floccose mycelium. Thus, mycelial morphology can be used as criterion to select which pairs must be used for optimizing compatible-mating studies. Hybrids resulting from cottony neohaplonts maintained the characteristically high growth rates of their parental strains with the hybrid R1-n xB1-n being faster than the latter.

  1. Developmental expression of estrogen receptor beta in the brain of prairie voles (Microtus ochrogaster).

    Science.gov (United States)

    Ploskonka, Stephanie D; Eaton, Jennifer L; Carr, Michael S; Schmidt, Jennifer V; Cushing, Bruce S

    2016-03-01

    Here, for the first time, the expression of estrogen receptor beta (ERβ) is characterized in the brains of the highly prosocial prairie vole (Microtus ochrogaster). ERβ immunoreactivity was compared in weanlings (postnatal Day 21) and adult males and females. The results indicate several major findings. First, unlike ERα, ERβ expression is not sexually dimorphic. Second, the adult pattern of ERβ-IR is established at the time of weaning, as there were no age-dependent effects on distribution. Finally, ERβ does not appear to be as widely distributed in voles compared with rats and mice. High levels of ERβ-IR were observed in several regions/nuclei within the medial pre-optic area, ventrolateral pre-optic nuclei, and in the hypothalamus, especially in the paraventricular and supraoptic nuclei. The visualization of ERβ in prairie voles is important as the socially monogamous prairie vole functions as a human relevant model system for studying the expression of social behavior and social deficit disorders. Future studies will now be able to determine the effect of treatments on the expression and/or development of ERβ in this highly social species.

  2. Sperm investment in male meadow voles is affected by the condition of the nearby male conspecifics.

    Science.gov (United States)

    Vaughn, Ashlee A; Delbarco-Trillo, Javier; Ferkin, Michael H

    2008-11-01

    Sperm competition occurs when 2 or more males copulate with a particular female during the same reproductive cycle, and their sperm compete to fertilize the female's available eggs. One strategy that male voles use to assess the risk and intensity of sperm competition involves responding to the presence of scent marks of conspecific males found near a sexually receptive female. Previously, we have shown that if a male vole copulated with a female while he was in the presence of the odors of another male he increased his sperm investment relative to his investment if another male's odors were not present. The aim of the present study was to test the hypothesis that males assess differences in the relative quality of competing males and adjust their sperm investment accordingly. We did so by allowing males to copulate when they were exposed to the scent mark of a 24-h food-deprived male (low-quality male) or the scent mark of a male that was not food deprived (high-quality male). The data indicate that male meadow voles did not increase their sperm investment during copulation when exposed to the scent mark of a food-deprived male but did so when they were exposed to the scent mark of a male that was not food deprived. The results support the hypothesis that male voles are able to adjust sperm investment when they encounter the scent marks of males that differ in quality.

  3. Trace metals in soil vegetation, and voles from mine land treated with sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Alberici, T.M.; Sopper, W.E.; Storm, G.L.; Yahner, R.H.

    Trace-metal concentrations in soil, vegetation, and tissues of meadow voles (Microtus pennsylvanicus) were compared on a stripmined site reclaimed conventionally (control site) and with municipal sludge (treated site) in Somerset County, Pennsylvania, in March and April 1983. With the exception of Zn concentrations in birdsfoot trefoil (Lotus corniculatus L.), reclamation with municipal sludge did not increase trace metal concentrations in soil, vegetation, or meadow voles in comparison to the site reclaimed conventionally. Zinc concentration in birdsfoot trefoil from the site reclaimed with sludge was higher than that from the site reclaimed conventionally but was below phytotoxic levels. Concentrations of Cu, Zn, Co, Cd, and Ni in vole tissues were not significantly different between control and treated sites. However, Cr concentrations in kidney and bone and Pb concentrations in liver and bone were higher on the control site than on the treated site. Stomach analyses indicated that meadow voles preferred tall fescue (Festuca arundinaceae L.) and quackgrass (Agropyron repens L.) to birdsfoot trefoil and orchardgrass (Dactylis glomerata L.) 27 refs., 1 fig., 8 tabs.

  4. Reproductive responses of male Brandt's voles ( Lasiopodomys brandtii) to 6-methoxybenzoxazolinone (6-MBOA) under short photoperiod

    Science.gov (United States)

    Dai, Xin; Jiang, Lian Yu; Han, Mei; Ye, Man Hong; Wang, Ai Qin; Wei, Wan Hong; Yang, Sheng Mei

    2016-04-01

    The plant secondary metabolite 6-methoxybenzoxazolinone (6-MBOA) can stimulate and enhance animal reproduction. This compound has been successfully detected in Leymus chinensis, which is the main diet of Brandt's voles. The aim of this study was to investigate the effect of different 6-MBOA doses on the reproductive physiology of male Brandt's voles under a short photoperiod. The results showed that 6-MBOA administration increased relative testis weight, regardless of the dose, but it had little effect on the body mass. Low and middle doses of 6-MBOA increased the concentrations of luteinizing hormone and testosterone in the serum and the mRNA levels of StAR and CYP11a1 in the testes. However, 6-MBOA did not cause any significant increase in the mRNA levels of KiSS-1, GPR54, and GnRH compared to those in the control group. The mRNA level of KiSS-1 in the arcuate nucleus (ARC) was higher than that in the anteroventral periventricular nucleus (AVPV). Collectively, our results demonstrated that the number of KiSS-1-expressing neurons located in the ARC was the highest, and that 6-MBOA, which might modulate the reproductive activity along the hypothalamic-pituitary-gonadal axis, had a dose-dependent stimulatory effect on the reproductive activity of Brandt's voles under a short photoperiod. Our study provided insights into the mechanism of 6-MBOA action and the factors influencing the onset of reproduction in Brandt's voles.

  5. Spontaneous expression of magnetic compass orientation in an epigeic rodent: the bank vole, Clethrionomys glareolus

    Science.gov (United States)

    Oliveriusová, Ludmila; Němec, Pavel; Pavelková, Zuzana; Sedláček, František

    2014-07-01

    Magnetoreception has been convincingly demonstrated in only a few mammalian species. Among rodents, magnetic compass orientation has been documented in four species of subterranean mole rats and two epigeic (i.e. active above ground) species—the Siberian hamster and the C57BL/6J mouse. The mole rats use the magnetic field azimuth to determine compass heading; their directional preference is spontaneous and unimodal, and their magnetic compass is magnetite-mediated. By contrast, the primary component of orientation response is learned in the hamster and the mouse, but both species also exhibit a weak spontaneous bimodal preference in the natural magnetic field. To determine whether the magnetic compass of wild epigeic rodents features the same functional properties as that of laboratory rodents, we investigated magnetic compass orientation in the bank vole Clethrionomys glareolus (Cricetidae, Rodentia). The voles exhibited a robust spontaneous bimodal directional preference, i.e. built nests and slept preferentially along the north-south axis, and deflected their directional preference according to a shift in the direction of magnetic north, clearly indicating that they were deriving directional information from the magnetic field. Thus, bimodal, axially symmetrical directional choice seems to be a common feature shared by epigeic rodents. However, spontaneous directional preference in the bank vole appeared to be more pronounced than that reported in the hamster and the mouse. These findings suggest that bank voles are well suited for future studies investigating the adaptive significance and mechanisms of magnetic orientation in epigeic rodents.

  6. FGF4 independent derivation of trophoblast stem cells from the common vole.

    Directory of Open Access Journals (Sweden)

    Elena V Grigor'eva

    Full Text Available The derivation of stable multipotent trophoblast stem (TS cell lines from preimplantation, and early postimplantation mouse embryos has been reported previously. FGF4, and its receptor FGFR2, have been identified as embryonic signaling factors responsible for the maintenance of the undifferentiated state of multipotent TS cells. Here we report the derivation of stable TS-like cell lines from the vole M. rossiaemeridionalis, in the absence of FGF4 and heparin. Vole TS-like cells are similar to murine TS cells with respect to their morphology, transcription factor gene expression and differentiation in vitro into derivatives of the trophectoderm lineage, and with respect to their ability to invade and erode host tissues, forming haemorrhagic tumours after subcutaneous injection into nude mice. Moreover, vole TS-like cells carry an inactive paternal X chromosome, indicating that they have undergone imprinted X inactivation, which is characteristic of the trophoblast lineage. Our results indicate that an alternative signaling pathway may be responsible for the establishment and stable proliferation of vole TS-like cells.

  7. Effects of vole fluctuations on the population dynamics of the barn owl Tyto alba

    NARCIS (Netherlands)

    Klok, T.C.; Roos, A.M.

    2007-01-01

    Many predator species feed on prey that fluctuates in abundance from year to year. Birds of prey can face large fluctuations in food abundance i.e. small mammals, especially voles. These annual changes in prey abundance strongly affect the reproductive success and mortality of the individual predato

  8. Puumala hantavirus infections in bank vole populations: host and virus dynamics in Central Europe.

    Science.gov (United States)

    Reil, Daniela; Rosenfeld, Ulrike M; Imholt, Christian; Schmidt, Sabrina; Ulrich, Rainer G; Eccard, Jana A; Jacob, Jens

    2017-02-28

    In Europe, bank voles (Myodes glareolus) are widely distributed and can transmit Puumala virus (PUUV) to humans, which causes a mild to moderate form of haemorrhagic fever with renal syndrome, called nephropathia epidemica. Uncovering the link between host and virus dynamics can help to prevent human PUUV infections in the future. Bank voles were live trapped three times a year in 2010-2013 in three woodland plots in each of four regions in Germany. Bank vole population density was estimated and blood samples collected to detect PUUV specific antibodies. We demonstrated that fluctuation of PUUV seroprevalence is dependent not only on multi-annual but also on seasonal dynamics of rodent host abundance. Moreover, PUUV infection might affect host fitness, because seropositive individuals survived better from spring to summer than uninfected bank voles. Individual space use was independent of PUUV infections. Our study provides robust estimations of relevant patterns and processes of the dynamics of PUUV and its rodent host in Central Europe, which are highly important for the future development of predictive models for human hantavirus infection risk.

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

    DEFF Research Database (Denmark)

    2013-01-01

    The metabolic rate of organisms may either be viewed as a basic property from which other vital rates and many ecological patterns emerge and that follows a universal allometric mass scaling law; or it may be considered a property of the organism that emerges as a result of the organism's adaptat......The metabolic rate of organisms may either be viewed as a basic property from which other vital rates and many ecological patterns emerge and that follows a universal allometric mass scaling law; or it may be considered a property of the organism that emerges as a result of the organism...... similar scaling but different elevations, such that the mass-specific rates converge on a rather narrow size-independent range. In contrast, ingestion and growth rates follow a near-universal taxa-independent ~3/4 mass scaling power law. We argue that the declining mass-specific clearance rates with size...

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

    Directory of Open Access Journals (Sweden)

    Pram Mahyudin

    1996-03-01

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

  11. Using wavelength-normalized optical spectroscopy to improve the accuracy of bacteria growth rate quantification

    Science.gov (United States)

    McBirney, Samantha E.; Trinh, Kristy; Wong-Beringer, Annie; Armani, Andrea M.

    2017-02-01

    One of the fundamental analytical measurements performed in microbiology is monitoring and characterizing cell concentration in culture media. Measurement error will give rise to reproducibility problems in a wide range of applications, from biomanufacturing to basic research. Therefore, it is critical that the generated results are consistent. Single wavelength optical density (OD) measurements have become the preferred approach. Here, we compare the conventional OD600 technique with a multi-wavelength normalized scattering optical spectroscopy method to measure the growth rates of Pseudomonas aeruginosa and Staphylococcus aureus, two of the leading nosocomial pathogens with proven abilities to develop resistance. The multi-wavelength normalization process minimizes the impact of bacteria byproducts and environmental noise on the signal, thereby accurately quantifying growth rates with high fidelity at low concentrations. In contrast, due to poor absorbance and scattering at 600 nm, the classic OD600 measurement method is able to detect bacteria but cannot quantify the growth rate reliably. Our wavelength-normalization protocol to detect bacteria growth rates can be readily and easily adopted by research labs, given that it only requires the use of a standard spectrophotometer and implementation of straightforward data analysis. Measuring and monitoring bacteria growth rates play a critical role in a wide range of settings, spanning from therapeutic design and development to diagnostics and disease prevention. Having a full understanding of the growth cycles of bacteria known to cause severe infections and diseases will lead to a better understanding of the pathogenesis of these illnesses, leading to better treatment and, ultimately, the development of a cure.

  12. On the Biomass Specific Growth Rates Estimation for Anaerobic Digestion using Differential Algebraic Techniques

    Directory of Open Access Journals (Sweden)

    Sette Diop

    2009-10-01

    Full Text Available The paper deals with identifiability and observability of anaerobic digestion (AD processes. In such kind of processes, generally carried out in continuously stirred tank bioreactors, the organic matter is depolluted by microorganisms into biogas and compost in the absence of oxygen. The biogas is an additional energy source, which can replace fossil fuel sources. The differential algebraic approach of general observation problems has been applied to investigate the identification and observation of a simple AD model. The major discovery is that the biomass specific growth rate can be stably estimated from easily measured quantities: the dilution rate and the biogas flow rate. Next if the yield coefficients are assumed known then, of course, the biomass concentration is observable. Unfortunately, even under the latter strongest assumption the substrate concentration is not observable. This concentration becomes observable if an additional model, say the Monod model, is assumed for the specific growth rate. Illustrative simulations are presented.

  13. Study on release rate of latent heat in Czochralski silicon growth

    Institute of Scientific and Technical Information of China (English)

    REN Bingyan; YANG Jiankun; LI Yanlin; LIU Xiaoping; WANG Minhua

    2006-01-01

    The pulling rate in czochralski silicon (CZSi) growth is important for reducing the cost of solar cell.In this paper, double-heater, heat shield and composite argon duct system were introduced in the Ф450 mm hot zone of a Czochralski furnace.The pulling rate under different thermal system was recorded in experiments.Argon flow and temperature fields were simulated by finite element method(FEM).Experimental results and numerical simulation indicate that double-heater and composite argon duct system can enhance obviously the release rate of latent heat.In Φ 200 mm Czochralski silicon (CZSi) growth, average pulling rate can increase from 0.6 mm·min-1 in the conventional hot zone to 0.8 mm·min-1 in the modified hot zone.

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

    Directory of Open Access Journals (Sweden)

    McPhee Ian

    2007-02-01

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

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

    Institute of Scientific and Technical Information of China (English)

    NI JinYu; HAO Yue; ZHANG JinCheng; YANG LinAn

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Widiastuti Karim

    2015-06-01

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

  17. A transcription factor links growth rate and metabolism in the hypersaline adapted archaeon Halobacterium salinarum.

    Science.gov (United States)

    Todor, Horia; Dulmage, Keely; Gillum, Nicholas; Bain, James R; Muehlbauer, Michael J; Schmid, Amy K

    2014-09-01

    Co-ordinating metabolism and growth is a key challenge for all organisms. Despite fluctuating environments, cells must produce the same metabolic outputs to thrive. The mechanisms underlying this 'growth homeostasis' are known in bacteria and eukaryotes, but remain unexplored in archaea. In the model archaeon Halobacterium salinarum, the transcription factor TrmB regulates enzyme-coding genes in diverse metabolic pathways in response to glucose. However, H. salinarum is thought not to catabolize glucose. To resolve this discrepancy, we demonstrate that TrmB regulates the gluconeogenic production of sugars incorporated into the cell surface S-layer glycoprotein. Additionally, we show that TrmB-DNA binding correlates with instantaneous growth rate, likely because S-layer glycosylation is proportional to growth. This suggests that TrmB transduces a growth rate signal to co-regulated metabolic pathways including amino acid, purine, and cobalamin biosynthesis. Remarkably, the topology and function of this growth homeostatic network appear conserved across domains despite extensive alterations in protein components.

  18. Molecular analysis of the in situ growth rates of subsurface Geobacter species.

    Science.gov (United States)

    Holmes, Dawn E; Giloteaux, Ludovic; Barlett, Melissa; Chavan, Milind A; Smith, Jessica A; Williams, Kenneth H; Wilkins, Michael; Long, Philip; Lovley, Derek R

    2013-03-01

    Molecular tools that can provide an estimate of the in situ growth rate of Geobacter species could improve understanding of dissimilatory metal reduction in a diversity of environments. Whole-genome microarray analyses of a subsurface isolate of Geobacter uraniireducens, grown under a variety of conditions, identified a number of genes that are differentially expressed at different specific growth rates. Expression of two genes encoding ribosomal proteins, rpsC and rplL, was further evaluated with quantitative reverse transcription-PCR (qRT-PCR) in cells with doubling times ranging from 6.56 h to 89.28 h. Transcript abundance of rpsC correlated best (r(2) = 0.90) with specific growth rates. Therefore, expression patterns of rpsC were used to estimate specific growth rates of Geobacter species during an in situ uranium bioremediation field experiment in which acetate was added to the groundwater to promote dissimilatory metal reduction. Initially, increased availability of acetate in the groundwater resulted in higher expression of Geobacter rpsC, and the increase in the number of Geobacter cells estimated with fluorescent in situ hybridization compared well with specific growth rates estimated from levels of in situ rpsC expression. However, in later phases, cell number increases were substantially lower than predicted from rpsC transcript abundance. This change coincided with a bloom of protozoa and increased attachment of Geobacter species to solid phases. These results suggest that monitoring rpsC expression may better reflect the actual rate that Geobacter species are metabolizing and growing during in situ uranium bioremediation than changes in cell abundance.

  19. Growth rate analysis and efficient experimental design for tumor xenograft studies.

    Science.gov (United States)

    Hather, Gregory; Liu, Ray; Bandi, Syamala; Mettetal, Jerome; Manfredi, Mark; Shyu, Wen-Chyi; Donelan, Jill; Chakravarty, Arijit

    2014-01-01

    Human tumor xenograft studies are the primary means to evaluate the biological activity of anticancer agents in late-stage preclinical drug discovery. The variability in the growth rate of human tumors established in mice and the small sample sizes make rigorous statistical analysis critical. The most commonly used summary of antitumor activity for these studies is the T/C ratio. However, alternative methods based on growth rate modeling can be used. Here, we describe a summary metric called the rate-based T/C, derived by fitting each animal's tumor growth to a simple exponential model. The rate-based T/C uses all of the data, in contrast with the traditional T/C, which only uses a single measurement. We compare the rate-based T/C with the traditional T/C and assess their performance through a bootstrap analysis of 219 tumor xenograft studies. We find that the rate-based T/C requires fewer animals to achieve the same power as the traditional T/C. We also compare 14-day studies with 21-day studies and find that 14-day studies are more cost efficient. Finally, we perform a power analysis to determine an appropriate sample size.

  20. Growth rate of matter perturbations as a probe of large-scale magnetism

    CERN Document Server

    Giovannini, Massimo

    2011-01-01

    The growth rate of matter perturbations is computed in a magnetized environment for the LambdaCDM and wCDM paradigms. It is argued that the baryons do not necessarily follow into the dark matter potential wells after they are released from the drag of the photons. The baryonic evolution equations inherit a forcing term whose explicit form depends on the plasma description and can be deduced, for instance, in the resistive magnetohydrodynamical approximation. After deriving an analytical expression for the growth rate applicable when dark energy does not cluster, the effects of relativistic corrections and of the inhomogeneities associated with the other species of the plasma are taken into account numerically. The spectral amplitudes and slopes of the stochastic magnetic background are selected to avoid appreciable distortions in the measured temperature and polarization anisotropies of the Cosmic Microwave Background. The growth of structures in the current paradigms of structure formation represents a compl...

  1. Wavy membranes and the growth rate of a planar chemical garden: Enhanced diffusion and bioenergetics

    CERN Document Server

    Ding, Yang; Steinbock, Oliver; Cartwright, Julyan H E; Cardoso, Silvana S S

    2016-01-01

    In order to model ion transport across protocell membranes in Hadean hydrothermal vents, we consider both theoretically and experimentally the planar growth of a precipitate membrane formed at the interface between two parallel fluid streams in a two-dimensional microfluidic reactor. The growth rate of the precipitate is found to be proportional to the square root of time, which is characteristic of diffusive transport. However, the dependence of the growth rate on the concentrations of hydroxide and metal ions is approximately linear and quadratic, respectively. We show that such a difference in ionic transport dynamics arises from the enhanced transport of metal ions across a thin gel layer present at the surface of the precipitate. The fluctuations in transverse velocity in this wavy porous gel layer allow an enhanced transport of the cation, so that the effective diffusivity is about an order of magnitude higher than that expected from molecular diffusion alone. Our theoretical predictions are in excellen...

  2. Final Report: "Collaborative Project. Understanding the Chemical Processes That Affect Growth Rates of Freshly Nucleated Particles"

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James N. [NCAR, Boulder, CO (United States); McMurry, Peter H. [NCAR, Boulder, CO (United States)

    2015-11-12

    This final technical report describes our research activities that have, as the ultimate goal, the development of a model that explains growth rates of freshly nucleated particles. The research activities, which combine field observations with laboratory experiments, explore the relationship between concentrations of gas-phase species that contribute to growth and the rates at which those species are taken up. We also describe measurements of the chemical composition of freshly nucleated particles in a variety of locales, as well as properties (especially hygroscopicity) that influence their effects on climate. Our measurements include a self-organized, DOE-ARM funded project at the Southern Great Plains site, the New Particle Formation Study (NPFS), which took place during spring 2013. NPFS data are available to the research community on the ARM data archive, providing a unique suite observations of trace gas and aerosols that are associated with the formation and growth of atmospheric aerosol particles.

  3. Radiocarbon-Based Ages and Growth Rates of Bamboo Corals from the Gulf of Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Roark, E B; Guilderson, T P; Flood-Page, S; Dunbar, R B; Ingram, B L; Fallon, S J; McCulloch, M

    2004-12-12

    Deep-sea coral communities have long been recognized by fisherman as areas that support large populations of commercial fish. As a consequence, many deep-sea coral communities are threatened by bottom trawling. Successful management and conservation of this widespread deep-sea habitat requires knowledge of the age and growth rates of deep-sea corals. These organisms also contain important archives of intermediate and deep-water variability, and are thus of interest in the context of decadal to century-scale climate dynamics. Here, we present {Delta}{sup 14}C data that suggest that bamboo corals from the Gulf of Alaska are long-lived (75-126 years) and that they acquire skeletal carbon from two distinct sources. Independent verification of our growth rate estimates and coral ages is obtained by counting seasonal Sr/Ca cycles and probable lunar cycle growth bands.

  4. Rate-dependent morphology of Li2O2 growth in Li-O2 batteries

    CERN Document Server

    Horstmann, B; Mitchell, R; Bessler, W G; Shao-Horn, Y; Bazant, M Z

    2013-01-01

    Compact solid discharge products enable energy storage devices with high gravimetric and volumetric energy densities, but solid deposits on active surfaces can disturb charge transport and induce mechanical stress. In this Letter we develop a nanoscale continuum model for the growth of Li2O2 crystals in lithium-oxygen batteries with organic electrolytes, based on a theory of electrochemical non-equilibrium thermodynamics originally applied to Li-ion batteries. As in the case of lithium insertion in phase-separating LiFePO4 nanoparticles, the theory predicts a transition from complex to uniform morphologies of Li2O2 with increasing current. Discrete particle growth at low discharge rates becomes suppressed at high rates, resulting in a film of electronically insulating Li2O2 that limits cell performance. We predict that the transition between these surface growth modes occurs at current densities close to the exchange current density of the cathode reaction, consistent with experimental observations.

  5. Radiocarbon-Based Ages and Growth Rates of Bamboo Corals from the Gulf of Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Roark, E B; Guilderson, T P; Flood-Page, S; Dunbar, R B; Ingram, B L; Fallon, S J; McCulloch, M

    2004-12-12

    Deep-sea coral communities have long been recognized by fisherman as areas that support large populations of commercial fish. As a consequence, many deep-sea coral communities are threatened by bottom trawling. Successful management and conservation of this widespread deep-sea habitat requires knowledge of the age and growth rates of deep-sea corals. These organisms also contain important archives of intermediate and deep-water variability, and are thus of interest in the context of decadal to century-scale climate dynamics. Here, we present {Delta}{sup 14}C data that suggest that bamboo corals from the Gulf of Alaska are long-lived (75-126 years) and that they acquire skeletal carbon from two distinct sources. Independent verification of our growth rate estimates and coral ages is obtained by counting seasonal Sr/Ca cycles and probable lunar cycle growth bands.

  6. Increased classical endoplasmic reticulum stress is sufficient to reduce chondrocyte proliferation rate in the growth plate and decrease bone growth.

    Directory of Open Access Journals (Sweden)

    Louise H W Kung

    Full Text Available Mutations in genes encoding cartilage oligomeric matrix protein and matrilin-3 cause a spectrum of chondrodysplasias called multiple epiphyseal dysplasia (MED and pseudoachondroplasia (PSACH. The majority of these diseases feature classical endoplasmic reticulum (ER stress and activation of the unfolded protein response (UPR as a result of misfolding of the mutant protein. However, the importance and the pathological contribution of ER stress in the disease pathogenesis are unknown. The aim of this study was to investigate the generic role of ER stress and the UPR in the pathogenesis of these diseases. A transgenic mouse line (ColIITgcog was generated using the collagen II promoter to drive expression of an ER stress-inducing protein (Tgcog in chondrocytes. The skeletal and histological phenotypes of these ColIITgcog mice were characterised. The expression and intracellular retention of Tgcog induced ER stress and activated the UPR as characterised by increased BiP expression, phosphorylation of eIF2α and spliced Xbp1. ColIITgcog mice exhibited decreased long bone growth and decreased chondrocyte proliferation rate. However, there was no disruption of chondrocyte morphology or growth plate architecture and perturbations in apoptosis were not apparent. Our data demonstrate that the targeted induction of ER stress in chondrocytes was sufficient to reduce the rate of bone growth, a key clinical feature associated with MED and PSACH, in the absence of any growth plate dysplasia. This study establishes that classical ER stress is a pathogenic factor that contributes to the disease mechanism of MED and PSACH. However, not all the pathological features of MED and PSACH were recapitulated, suggesting that a combination of intra- and extra-cellular factors are likely to be responsible for the disease pathology as a whole.

  7. Beyond reduced-impact logging: silvicultural treatments to increase growth rates of tropical trees

    NARCIS (Netherlands)

    Peña-Claros, M.; Fredericksen, T.S.; Alarcón, A.; Blate, G.M.; Choque, U.; Leaño, C.; Licona, J.C.; Mostacedo, B.; Pariona, W.; Villegas, Z.; Putz, F.E.

    2008-01-01

    Use of reduced-impact logging (RIL) techniques has repeatedly been shown to reduce damage caused by logging. Unfortunately, these techniques do not necessarily ameliorate the low growth rates of many commercial species or otherwise assure recovery of the initial volume harvested during the next cutt

  8. Automatic tuning and adaptation for specific growth rate control of fed-batch cultivation

    NARCIS (Netherlands)

    Soons, Z.I.T.A.; Straten, van G.; Boxtel, van A.J.B.

    2006-01-01

    To ensure consistency between fed-batch cultivations for the production of vaccines or other bio-pharmaceuticals it is desirable to control the specific growth rate to a pre-set constant value. This is a challenge because the dynamics of the process is considerably changing due to the increase in

  9. Quantitative physiology of Lactococcus lactis at extreme low-growth rates

    NARCIS (Netherlands)

    Ercan, O.; Smid, E.J.; Kleerebezem, M.

    2013-01-01

    This paper describes the metabolic adaptation of Lactococcus lactis during the transition from a growing to a non-growing state using retentostat cultivation. Under retentostat cultivation, the specific growth rate decreased from 0.025 h-1 to 0.0001 h-1 in 42 days, while doubling time increased to m

  10. Automatic Stand Modeling of Casting Rate Influence on Solid Phase Growth of Round Ingot inside Crystallizer

    Directory of Open Access Journals (Sweden)

    A. N. Chichko

    2006-01-01

    Full Text Available The method of calculation and results of computer dynamics modeling of solid ingot skin in a crystallizer are presented in the paper. The paper shows influence of ingot drawing rate on dynamics of solid ingot skin growth in the continuous casting machine at steel grades used at Republic Unitary Enterprise «Belarussian Metallurgical Works» (BMZ.

  11. Growth, exchange rates and trade in Brazil: a structuralist post-Keynesian approach

    Directory of Open Access Journals (Sweden)

    Nelson H. Barbosa Filho

    2004-01-01

    Full Text Available This paper presents a structuralist post-Keynesian analysis of trade adjustment in Brazil. Based on the concept of the balance-of-payments (BoP constraint on growth, the paper investigates the relationship between income growth and real-exchange-rate devaluation necessary to adjust trade to a foreign-exchange constraint. The main result is that, with price-inelastic and income-elastic imports and based on its trade structure in 2002, Brazil may have to compensate an additional 1% of income growth with approximately 7% of real-exchange-rate devaluation in order to keep its trade balance stable in relation to GDP in the near future. Moreover, the trade parameters of Brazil seem to be unfavorable to growth with stable trade, that is, even moderate rates of GDP expansion lead to a substantial increase of imports and, therefore, require an also substantial devaluation of the real exchange rate to avoid a deterioration of the trade balance.

  12. Capitalizing on the Dynamic Features of Excel to Consider Growth Rates and Limits

    Science.gov (United States)

    Taylor, Daniel; Moore-Russo, Deborah

    2012-01-01

    It is common for both algebra and calculus instructors to use power functions of various degrees as well as exponential functions to examine and compare rates of growth. This can be done on a chalkboard, with a graphing calculator, or with a spreadsheet. Instructors often are careful to connect the symbolic and graphical (and occasionally the…

  13. Prediction of Microbial Growth Rate versus Biomass Yield by a Metabolic Network with Kinetic Parameters

    NARCIS (Netherlands)

    Adadi, Roi; Volkmer, Benjamin; Milo, Ron; Heinemann, Matthias; Shlomi, Tomer

    2012-01-01

    Identifying the factors that determine microbial growth rate under various environmental and genetic conditions is a major challenge of systems biology. While current genome-scale metabolic modeling approaches enable us to successfully predict a variety of metabolic phenotypes, including maximal bio

  14. Growth and yield responses of broccoli cultivars to different rates of nitrogen at western Chitwan, Nepal

    DEFF Research Database (Denmark)

    Giri, Raj Kumar; Sharma, Moha Datta; Shakya, Santa Man

    2013-01-01

    A field experiment was conducted with the objective to determine the optimum rate of nitrogen (N) fertilizer for effective growth and yield of two varieties of broccoli in southern plain of Nepal. The experiment was laid out with two-factorial completely random block design (RCBD) comprising two ...

  15. Linking root traits to potential growth rate in six temperate tree species

    NARCIS (Netherlands)

    Comas, L.H.; Bouma, T.J.; Eissenstat, D.M.

    2002-01-01

    There is an extremely limited understanding of how plants of different potential growth rate vary in root traits, especially in woody species. We contrasted fine root morphology, physiology, and elemental construction between a fast- and a slow-growing species in each of three families: Aceraceae (m

  16. The effects of supplemental Sericea lespedeza pellets in lambs and kids. 1. Growth rate

    Science.gov (United States)

    Sericea lespedeza (SL; Lespedeza cuneata) has been used in recent years to aid in the control of gastrointestinal nematodes (GIN) in sheep and goats. Grazing or feeding dried SL leads to a reduction in egg production by GIN and reduces coccidiosis. Growth rates in lambs and kids when fed SL for mo...

  17. STRONG LAW OF LARGE NUMBERS AND GROWTH RATE FOR NOD SEQUENCES

    Institute of Scientific and Technical Information of China (English)

    MA Song-lin; WANG Xue-jun

    2015-01-01

    In the paper, we get the precise results of Hájek-Rényi type inequalities for the par-tial sums of negatively orthant dependent sequences, which improve the results of Theorem 3.1 and Corollary 3.2 in Kim (2006) and the strong law of large numbers and strong growth rate for negatively orthant dependent sequences.

  18. Growth, exchange rates and trade in Brazil: a structuralist post Keynesian approach

    Directory of Open Access Journals (Sweden)

    Nelson H. Barbosa Filho

    2009-06-01

    Full Text Available This paper presents a structuralist post-Keynesian analysis of trade adjustment in Brazil. Based on the concept of the balance-of-payments (BoP constraint on growth, the paper investigates the relationship between income growth and real-exchange-rate devaluation necessary to adjust trade to a foreign-exchange constraint. The main result is that, with price-inelastic and income-elastic imports and based on its trade structure in 2002, Brazil may have to compensate an additional 1% of income growth with approximately 7% of real-exchange-rate devaluation in order to keep its trade balance stable in relation to GDP in the near future. Moreover, the trade parameters of Brazil seem to be unfavorable to growth with stable trade, that is, even moderate rates of GDP expansion lead to a substantial increase of imports and, therefore, require an also substantial devaluation of the real exchange rate to avoid a deterioration of the trade balance.

  19. Prediction of Microbial Growth Rate versus Biomass Yield by a Metabolic Network with Kinetic Parameters

    NARCIS (Netherlands)

    Adadi, Roi; Volkmer, Benjamin; Milo, Ron; Heinemann, Matthias; Shlomi, Tomer

    Identifying the factors that determine microbial growth rate under various environmental and genetic conditions is a major challenge of systems biology. While current genome-scale metabolic modeling approaches enable us to successfully predict a variety of metabolic phenotypes, including maximal

  20. Growth rate and maturation of skeletal muscles over a size range of galliform birds

    NARCIS (Netherlands)

    Dietz, MW; Ricklefs, RE; Ricklefs, Robert E.

    1997-01-01

    The relationship between growth rate and development of function in leg and pectoral muscles was studied in four species of galliform birds ranging from 125 g to 18 kg and, for comparison, in an altricial species, the European starling (80 g). An index to neonatal maturity (muscle dry content propor

  1. Growth rate of multiple intracranial hydatid cysts assessed by CT from the time of embolisation

    Energy Technology Data Exchange (ETDEWEB)

    Evliyaoglu, C.; Yuksel, M.; Gul, B.; Kaptanoglu, E.; Yaman, M. [Ankara Numune Hastanesi, Beyin Cerrahisi Klinigi, Ankara (Turkey)

    1998-06-01

    We report the case of a 25-year-old man with multiple bilateral hydatid cysts of the brain in whom we were able to assess the growth rate of the cysts on repeated examination. On average, the cysts increased in diameter by 1 cm per month. (orig.) With 5 figs., 6 refs.

  2. A Study on the Rate of Contribution of Education Investment to the Economic Growth in China

    Science.gov (United States)

    Fan, Bo-nai; Lai, Xiong-xiang

    2006-01-01

    There is an evident bi-directional causality relationship between education investment and economic growth based on an analysis of statistics from 1952 to 2003 released by the State Statistics Bureau. A generalized difference regression model is set up to investigate the relationship between the two. Studies show that the rate of contribution of…

  3. Effect of temperature on microbial growth rate - thermodynamic analysis, the arrhenius and eyring-polanyi connection

    Science.gov (United States)

    The objective of this work is to develop a new thermodynamic mathematical model for evaluating the effect of temperature on the rate of microbial growth. The new mathematical model is derived by combining the Arrhenius equation and the Eyring-Polanyi transition theory. The new model, suitable for ...

  4. Extracting growth rates from the non-laminated coralline sponge Astrosclera willeyana using "bomb" radiocarbon

    Energy Technology Data Exchange (ETDEWEB)

    Fallon, S; Guilderson, T

    2004-06-30

    Coralline sponges have the potential to fill in gaps in our understanding of subsurface oceanographic variability. However, one disadvantage they have compared to hermatypic reef building coral proxies is that they do not have annual density bands and need to be radiometrically dated for an age determination. To elucidate growth rate variability we have measured radiocarbon in 1 mm increments from Astrosclera willeyana sponges collected off the Central and Northern Great Barrier Reef (GBR) and from Truk in the Caroline Islands and compared these radiocarbon profiles to independently dated coral radiocarbon records. Growth rates of the GBR sponges average 1.2 {+-} 0.3 and 1.0 {+-} 0.3 mm yr{sup -1}, north and central respectively but can vary by a factor of two. The growth rate of the Truk sponge averages 1.2 {+-} 0.1 mm yr{sup -1}. These growth rates are significantly faster to those measured for other GBR Astrosclera willeyana sponges (0.2 mm yr{sup -1}) by Calcein staining (Woerheide 1988).

  5. Influence of High Strength Steel Microstructure on Fatigue Crack Growth Rate

    Directory of Open Access Journals (Sweden)

    Enefola S. Ameh

    2016-07-01

    Full Text Available This study examines the effect of high strength steel microstructure morphology on fatigue crack growth rate (FCGR. To achieve this aim, three different heat treatment methods (normalizing, austempering quenching and tempering were considered and all the steel specimens were initially heated to 9500C austenization temperature for ninety minutes and then processed via the different heat treatment methods before viewing the resultant microstructures under light optical microscope (LOM. Fatigue crack growth rate tests were conducted on the resultant microstructures with compact tension specimens at room temperature as prescribed by American standard testing method E647. Results of FCGR tests showed normalized microstructure has the lowest FCGR (6.2698E-06, followed by quenched and tempered (7.9519E-06, asreceived (8.15E-06 and austempered (9.6667E-06 microstructure considering a low stress intensity factor range. The trend of results showed insignificant effect of microstructure over the Paris regime growth indicating fatigue crack growth rate is not a reliable parameter for correlating rate of crack propagation to microstructure

  6. Investigations into the relationship of post-stress metabolic rates and growth of fishes

    Science.gov (United States)

    The objective of this study was to determine if respirometry indices of fish following a stressor correspond with growth. On four occasions over a period of one month, oxygen consumption rates of 16 hybrid striped bass families were measured following a standardized handling stressor. Groups of 10...

  7. Does warming affect growth rate and biomass production of shrubs in the High Arctic?

    DEFF Research Database (Denmark)

    Campioli, Matteo; Schmidt, Niels Martin; Albert, Kristian Rost

    2013-01-01

    Few studies have assessed directly the impact of warming on plant growth and biomass production in the High Arctic. Here, we aimed to investigate the impact of 7 years of warming (open greenhouses) on the aboveground relative growth rate (RGR) of Cassiope tetragona and Salix arctica in North......-Eastern Greenland. RGR was assessed for apical (leaves, stem, reproductive organs) and lateral meristems (secondary growth of stem and branches) and accompanied by measures of gross ecosystem production (GEP), branching and tissue carbon (C) concentration. Measurements were based on harvest and biometric methods...... limits the growth of Cassiope but not that of Salix in North-Eastern Greenland. Summer warming thus has the potential to stimulate biomass production in the High Arctic but major species-specific differences are expected....

  8. Are physicians profit or rent seekers? Some evidence from state economic growth rates.

    Science.gov (United States)

    Reilly, Mary; Santerre, Rexford E

    2013-01-01

    Previous research has debated whether physicians act as profit- or rent-seekers. We argue that these two models of physician behavior can be tested by observing empirically the relationship between physician density and economic growth rates. A direct (inverse) relationship provides evidence for the profit-seeking (rent-seeking) theory of physician behavior. We empirically examine the impact of physician density on the economic growth of all US states over the period from 1973 to 2009. The empirical analysis generally finds a statistically significant and direct relationship between physician density and the growth of gross state product. The results are robust with respect to state- and time-fixed effects, individual state time trends, and 2SLS (two-stage least squares) estimation. Thus, in support of the profit-seeking theory of physician behavior, the findings reveal that physicians generally have a positive impact on the growth of the US economy.

  9. Effect of band-overload on fatigue crack growth rate of HSLA steel

    Science.gov (United States)

    Abhinay, S. V.; Tenduwe, Om Prakash; Kumar, Ajit; Dutta, K.; Verma, B. B.; Ray, P. K.

    2015-02-01

    Fatigue crack growth behavior is important parameter of structural materials. This parameters can be used to predict their life, service reliability and operational safety in different conditions. The material used in this investigation is an HSLA steel. In this investigation effect of single overload and band-overload on fatigue crack growth of same steel are studied using compact tension (CT) specimens under mode-I condition and R=0.3. It is observed that overload and band-overload applications resulted retardation on the fatigue crack growth rate in most of the cases. It is also noticed that maximum retardation took place on application of seven successive overload cycles. Application of ten and more overload cycles caused no crack growth retardation.

  10. The effect of differential growth rates across plants on spectral predictions of physiological parameters.

    Directory of Open Access Journals (Sweden)

    Tal Rapaport

    Full Text Available Leaves of various ages and positions in a plant's canopy can present distinct physiological, morphological and anatomical characteristics, leading to complexities in selecting a single leaf for spectral representation of an entire plant. A fortiori, as growth rates between canopies differ, spectral-based comparisons across multiple plants--often based on leaves' position but not age--becomes an even more challenging mission. This study explores the effect of differential growth rates on the reflectance variability between leaves of different canopies, and its implication on physiological predictions made by widely-used spectral indices. Two distinct irrigation treatments were applied for one month, in order to trigger the formation of different growth rates between two groups of grapevines. Throughout the experiment, the plants were physiologically and morphologically monitored, while leaves from every part of their canopies were spectrally and histologically sampled. As the control vines were constantly developing new leaves, the water deficit plants were experiencing growth inhibition, resulting in leaves of different age at similar nodal position across the treatments. This modification of the age-position correlation was characterized by a near infrared reflectance difference between younger and older leaves, which was found to be exponentially correlated (R(2 = 0.98 to the age-dependent area of intercellular air spaces within the spongy parenchyma. Overall, the foliage of the control plant became more spectrally variable, creating complications for intra- and inter-treatment leaf-based comparisons. Of the derived indices, the Structure-Insensitive Pigment Index (SIPI was found indifferent to the age-position effect, allowing the treatments to be compared at any nodal position, while a Normalized Difference Vegetation Index (NDVI-based stomatal conductance prediction was substantially affected by differential growth rates. As various

  11. Predicting growth rates and growth boundary of Listeria monocytogenes - An international validation study with focus on processed and ready-to-eat meat and seafood

    DEFF Research Database (Denmark)

    Mejlholm, Ole; Gunvig, A.; Borggaard, C.

    2010-01-01

    they take into account. The most complex model included the effect of nine environmental parameters and it performed better than the other less complex models both for prediction of maximum specific growth rates (mu(max) values) and for the growth boundary of L. monocytogenes. For this model bias...... and accuracy factors for growth rate predictions were 1.0 and 1.5, respectively, and 89% of the growth/no-growth responses were correctly predicted. The performance of three other models, including the effect of five to seven environmental parameters, was considered acceptable with bias factors of 1.2 to 1...... to accurately predict growth responses of L. monocytogenes in the wide range of food evaluated in the present study. When complexity of L monocytogenes growth models matches the complexity of foods of interest. i.e. the number of hurdles to microbial growth, then predicted growth responses of the pathogen can...

  12. Effects of growth hormone transgenesis on metabolic rate, exercise performance and hypoxia tolerance in tilapia hybrids

    DEFF Research Database (Denmark)

    McKenzie, DJ; Martinez, R; Morales, A

    2003-01-01

    Swimming respirometry was employed to compare inactive metabolic rate (Rr), maximum metabolic rate (Rmax), resultant aerobic scope and maximum sustainable (critical) swimming speed (Ucrit), in growth hormone transgenic (GHT) and wild-type (W) tilapia Oreochromis sp. hybrids. Although the Rr of GHT...... tilapia also exhibited the same capacity to regulate oxygen uptake during progressive hypoxia, despite the fact that the GHT fish were defending a higher demand for O2. The results indicate that ectopic expression of GH raises metabolic rate in tilapia, but the fish compensate for this metabolic load...

  13. Warming, soil moisture, and loss of snow increase Bromus tectorum’s population growth rate

    Directory of Open Access Journals (Sweden)

    Aldo Compagnoni

    2014-01-01

    Full Text Available Abstract Climate change threatens to exacerbate the impacts of invasive species. In temperate ecosystems, direct effects of warming may be compounded by dramatic reductions in winter snow cover. Cheatgrass (Bromus tectorum is arguably the most destructive biological invader in basins of the North American Intermountain West, and warming could increase its performance through direct effects on demographic rates or through indirect effects mediated by loss of snow. We conducted a two-year experimental manipulation of temperature and snow pack to test whether 1 warming increases cheatgrass population growth rate and 2 reduced snow cover contributes to cheatgrass’ positive response to warming. We used infrared heaters operating continuously to create the warming treatment, but turned heaters on only during snowfalls for the snowmelt treatment. We monitored cheatgrass population growth rate and the vital rates that determine it: emergence, survival and fecundity. Growth rate increased in both warming and snowmelt treatments. The largest increases occurred in warming plots during the wettest year, indicating that the magnitude of response to warming depends on moisture availability. Warming increased both fecundity and survival, especially in the wet year, while snowmelt contributed to the positive effects of warming by increasing survival. Our results indicate that increasing temperature will exacerbate cheatgrass impacts, especially where warming causes large reductions in the depth and duration of snow cover.

  14. Endosulfan induced changes in growth rate, pigment composition and photosynthetic activity of mosquito fern Azolla microphylla

    Directory of Open Access Journals (Sweden)

    Raja W.

    2012-11-01

    Full Text Available This paper is the first in a series reporting a study on the effects of different concentrations of insecticide, Endosulfan (0-600ppm was premeditated on 5th day after insecticide exposure with respect to growth rate, pigment composition and photosynthetic activity of Azolla microphylla under laboratory conditions which become non-target organism in the rice fields. Endosulfan inhibited the relative growth rate, pigment content and photosynthetic O2 evolution. Phycocyanin was main target followed by carotenoid and total chlorophyll. Significant increase in pigment, flavonoid and Anthocyanin was noticed after six days of treatment. In contrast to the photosynthetic activity, the rate of respiration in Azolla microphylla was increased significantly. Our results show that Endosulfan at normally recommended field rates and intervals are seldom deleterious to the beneficial and Eco friendly Azolla microphylla and their activities and thus in turn suppress plant growth and development. Phytotoxity of Azolla microphylla can be minimized by restrictions on application, timing, method and rate of application.

  15. Growth rates of young-of-year shovelnose sturgeon in the Upper Missouri River

    Science.gov (United States)

    Braaten, P. J.; Fuller, D.B.

    2007-01-01

    Information on growth during the larval and young-of-year life stages in natural river environments is generally lacking for most sturgeon species. In this study, methods for estimating ages and quantifying growth were developed for field-sampled larval and young-of-year shovelnose sturgeon Scaphirhynchus platorynchus in the upper Missouri River. First, growth was assessed by partitioning samples of young-of-year shovelnose sturgeon into cohorts, and regressing weekly increases in cohort mean length on sampling date. This method quantified relative growth because ages of the cohorts were unknown. Cohort increases in mean length among sampling dates were positively related (P  0.59 for all cohorts) to sampling date, and yielded growth rate estimates of 0.80–2.95 mm day−1 (2003) and 0.44–2.28 mm day−1 (2004). Highest growth rates occurred in the largest (and earliest spawned) cohorts. Second, a method was developed to estimate cohort hatch dates, thus age on date of sampling could be determined. This method included quantification of post-hatch length increases as a function of water temperature (growth capacity; mm per thermal unit, mm TU−1), and summation of mean daily water temperatures to achieve the required number of thermal units that corresponded to post-hatch lengths of shovelnose sturgeon on sampling dates. For six of seven cohorts of shovelnose sturgeon analyzed, linear growth models (r2 ≥ 0.65, P Gompertz growth models (r2 ≥ 0.83, P < 0.0001) quantified length-at-age from hatch through 55 days post-hatch (98–100 mm). Comparisons of length-at-age derived from the growth models indicated that length-at-age was greater for the earlier-hatched cohorts than later-hatched cohorts. Estimated hatch dates for different cohorts were corroborated based on the dates that newly-hatched larval shovelnose sturgeon were sampled in the drift. These results provide the first quantification of growth dynamics for field-sampled age-0

  16. Investigating the asymmetric relationship between inflation-output growth exchange rate changes

    Science.gov (United States)

    Chu, Jenq Fei; Sek, Siok Kun

    2017-08-01

    The relationship between inflation-output growth or output variation has long been studied. In this study, we extend the investigation under two exchange rate flexibility/regime in four Asian countries (Indonesia, Korea, Philippines and Thailand) that have experienced drastic exchange rate regime changes aftermath the financial crisis of 1997. These countries have switched from fixed/rigid exchange rate regime to flexible exchange rate and inflation targeting (IT) regime after the crisis. Our main objective is to compare the inflation-output trade-off relationship in the pre-IT and post-IT periods as a tool to evaluate the efficiency of monetary policy. A nonlinear autoregressive distributed lags (NARDL) model is applied to capture the asymmetric effects of exchange rate changes (increases and decreases). The data ranging from 1981M1 onwards till 2016M3. Our results show that exchange rate has asymmetric effect on inflation both short-run and long-run with larger impact in the post-IT period under flexible regime. Depreciation of exchange rate has leads to higher inflation. Furthermore, we find evidences on the relationship between inflation and growth in both short-run and long-run, but the trade-off only detected in the short run both in the pre- and post-IT periods.

  17. Copper and silver selenide crystal growth rate measurements as a method for determination of ionic conductivity

    Science.gov (United States)

    Vučić, Zlatko; Lovrić, Davorin; Gladić, Jadranko; Etlinger, Božidar

    2004-03-01

    The motivation behind this work is the discrepancy between the measured and calculated growth rates of copper selenide spherical single crystals between 740 and 800 K. The growth of cylindrical polycrystalline samples of copper selenide at high temperatures was monitored in experiments that enabled full control of the geometry of growth. Together with the calculations based on Yokota's transport equation, these measurements eliminated ionic conductivity data as a possible reason behind too high values of the calculated growth rates. The equivalent growth experiments on polycrystalline silver selenide samples were performed as a test of the method, yielding excellent agreement with the results obtained by extrapolation of existing data. On the basis of these measurements and associated analysis, this method is proposed as a method for determination of ionic conductivity of mixed superionic conductors on temperatures up to the temperatures of melting, i.e. in the range in which other methods of ionic conductivity measurements either do not work or are not accurate enough.

  18. Interspecies variation in mammary gland growth rate: relationship to gestation length.

    Science.gov (United States)

    Sheffield, L G; Anderson, R R

    1985-10-01

    Growth of the mammary gland is measured by several indices including total wet weight, dry fat-free tissue, and deoxyribonucleic acid. The latter is a superior measure of true growth because it represents changes of cell numbers. Sufficient data have been generated to determine the relationship among species of mammals between gestation length and differences in rates of mammary growth. Exponential growth equations were estimated for eight mammalian species with gestation lengths from 16.5 d for the hamster to 280 d for the cow. The form of the most appropriate equation was Y = AeBx, where Y is mammary deoxyribonucleic acid or dry fat-free tissue, x is day of gestation, e is the base of natural logs, and A and B are constants. The A term was related to body weight (W) and the B-term to gestation length (G). Resulting equations were deoxyribonucleic acid (mg) = .0547W.803 e1.98 G-.98x and dry fat-free tissue (mg) = 2.35W.779 e.719 G-.77x. First-order rate constants of mammary growth ranged in a reverse order from a high of .141 d-1 in hamsters to a low of .008 d-1 in cows; in other words, mammary deoxyribonucleic acid in hamsters doubled in 4.9 d but in the bovine it took 87 d to double.

  19. Influence of Ni Catalyst Layer and TiN Diffusion Barrier on Carbon Nanotube Growth Rate

    Directory of Open Access Journals (Sweden)

    Mérel Philippe

    2010-01-01

    Full Text Available Abstract Dense, vertically aligned multiwall carbon nanotubes were synthesized on TiN electrode layers for infrared sensing applications. Microwave plasma-enhanced chemical vapor deposition and Ni catalyst were used for the nanotubes synthesis. The resultant nanotubes were characterized by SEM, AFM, and TEM. Since the length of the nanotubes influences sensor characteristics, we study in details the effects of changing Ni and TiN thickness on the physical properties of the nanotubes. In this paper, we report the observation of a threshold Ni thickness of about 4 nm, when the average CNT growth rate switches from an increasing to a decreasing function of increasing Ni thickness, for a process temperature of 700°C. This behavior is likely related to a transition in the growth mode from a predominantly “base growth” to that of a “tip growth.” For Ni layer greater than 9 nm the growth rate, as well as the CNT diameter, variations become insignificant. We have also observed that a TiN barrier layer appears to favor the growth of thinner CNTs compared to a SiO2 layer.

  20. Food consumption and growth rates of juvenile black carp fed natural and prepared feeds

    Science.gov (United States)

    Hodgins, Nathaniel C.; Schramm, Harold L.; Gerard, Patrick D.

    2014-01-01

    The introduced mollusciphagic black carp Mylopharyngodon piceus poses a significant threat to native mollusks in temperate waters throughout the northern hemisphere, but consumption rates necessary to estimate the magnitude of impact on mollusks have not been established. We measured food consumption and growth rates for small (77–245 g) and large (466–1,071 g) triploid black carp held individually under laboratory conditions at 20, 25, and 30°C. Daily consumption rates (g food · g wet weight fish−1·d−1·100) of black carp that received prepared feed increased with temperature (small black carp 1.39–1.71; large black carp 1.28–2.10), but temperature-related increases in specific growth rate (100[ln(final weight) - ln(initial weight)]/number of days) only occurred for the large black carp (small black carp −0.02 to 0.19; large black carp 0.16–0.65). Neither daily consumption rates (5.90–6.28) nor specific growth rates (0.05–0.24) differed among temperatures for small black carp fed live snails. The results of these laboratory feeding trials indicate food consumption rates can vary from 289.9 to 349.5 J·g−1·d−1 for 150 g black carp receiving prepared feed, from 268.8 to 441.0 J·g−1·d−1for 800 g black carp receiving prepared feed, and from 84.8 to 90.2 J·g−1·d−1 for 150 g black carp that feed on snails. Applying estimated daily consumption rates to estimated biomass of native mollusks indicates that a relatively low biomass of bla

  1. Improvement of growth rate of plants by bubble discharge in water

    Science.gov (United States)

    Takahata, Junichiro; Takaki, Koichi; Satta, Naoya; Takahashi, Katsuyuki; Fujio, Takuya; Sasaki, Yuji

    2015-01-01

    The effect of bubble discharge in water on the growth rate of plants was investigated experimentally for application to plant cultivation systems. Spinach (Spinacia oleracea), radish (Raphanus sativus var. sativus), and strawberry (Fragaria × ananassa) were used as specimens to clarify the effect of the discharge treatment on edible parts of the plants. The specimens were cultivated in pots filled with artificial soil, which included chicken manure charcoal. Distilled water was sprayed on the artificial soil and drained through a hole in the pots to a water storage tank. The water was circulated from the water storage tank to the cultivation pots after 15 or 30 min discharge treatment on alternate days. A magnetic compression-type pulsed power generator was used to produce the bubble discharge with a repetition rate of 250 pps. The plant height in the growth phase and the dry weight of the harvested plants were improved markedly by the discharge treatment in water. The soil and plant analyzer development (SPAD) value of the plants also improved in the growth phase of the plants. The concentration of nitrate nitrogen, which mainly contributed to the improvement of the growth rate, in the water increased with the discharge treatment. The Brix value of edible parts of Fragaria × ananassa increased with the discharge treatment. The inactivation of bacteria in the water was also confirmed with the discharge treatment.

  2. Light pollution reduces activity, food consumption and growth rates in a sandy beach invertebrate.

    Science.gov (United States)

    Luarte, T; Bonta, C C; Silva-Rodriguez, E A; Quijón, P A; Miranda, C; Farias, A A; Duarte, C

    2016-11-01

    The continued growth of human activity and infrastructure has translated into a widespread increase in light pollution. Natural daylight and moonlight cycles play a fundamental role for many organisms and ecological processes, so an increase in light pollution may have profound effects on communities and ecosystem services. Studies assessing ecological light pollution (ELP) effects on sandy beach organisms have lagged behind the study of other sources of disturbance. Hence, we assessed the influence of this stressor on locomotor activity, foraging behavior, absorption efficiency and growth rate of adults of the talitrid amphipod Orchestoidea tuberculata. In the field, an artificial light system was assembled to assess the local influence of artificial light conditions on the amphipod's locomotor activity and use of food patches in comparison to natural (ambient) conditions. Meanwhile in the laboratory, two experimental chambers were set to assess amphipod locomotor activity, consumption rates, absorption efficiency and growth under artificial light in comparison to natural light-dark cycles. Our results indicate that artificial light have significantly adverse effects on the activity patterns and foraging behavior of the amphipods, resulting on reduced consumption and growth rates. Given the steady increase in artificial light pollution here and elsewhere, sandy beach communities could be negatively affected, with unexpected consequences for the whole ecosystem. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Subcritical crack growth in oxide and non-oxide ceramics using the Constant Stress Rate Test

    Directory of Open Access Journals (Sweden)

    Agnieszka Wojteczko

    2015-12-01

    Full Text Available Fracture toughness is one of the most important parameters for ceramics description. In some cases, material failure occurs at lower stresses than described by KIc parameter. In these terms, determination of fracture toughness only, proves to be insufficient. This may be due to environmental factors, such as humidity, which might cause subcritical crack propagation in a material. Therefore, it is very important to estimate crack growth velocities to predict lifetime of ceramics used under specific conditions. Constant Stress Rate Test is an indirect method of subcritical crack growth parameters estimation. Calculations are made by using strength data, thus avoiding crack measurement. The expansion of flaws causes reduction of material strength. If subcritical crack growth phenomenon occurs, critical value of crack lengths increases with decreasing stress rate due to longer time for flaw to grow before the critical crack propagation at KIc takes place. Subcritical crack growth phenomenon is particularly dangerous for oxide ceramics due to chemical interactions occurring as a result of exposure to humidity. This paper presents results of Constant Stress Rate Test performed for alumina, zirconia, silicon carbide and silicon nitride in order to demonstrate the differences in subcritical crack propagation phenomenon course.

  4. High Temperature Fatigue Crack Growth Rate of G91 Steel with Applying 30 Seconds Hold Time

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Bum; Park, Chang Gyu; Koo, Gyeong Hoi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, Jong Hoon [Sungkyunkwan University, Suwon (Korea, Republic of); Kim, Bum Joon [Osan Univ., Osan (Korea, Republic of)

    2015-05-15

    Subsection NH since 2004. The database of creep and creep-fatigue crack growth rate of G91 steel is necessary for the structural integrity evaluation of the SFR structures because the database of these properties of materials is insufficient through the world. Moreover, it is difficult to use the database which is gained by the research center of advanced countries because it is not to be opened. Therefore, it is necessary to make an effort to get the database of material properties. Creep-fatigue crack initiation and growth tests for a G91 tubular specimen, including a machined defect, have been performed by Kim and it attempted to assess a high temperature crack behavior of G91 side plate specimen by Lee. Creep-fatigue crack growth rate were compared in terms of different temperature range. Tests were performed at temperatures of 500, 550 and 600, respectively. Stress ratio was set to 0.1 and trapezoidal shape of stress condition was applied to the specimens to perform the creep-fatigue crack growth rate tests. Each specimen's surface was polished and fatigue pre-crack was manufactured by fatigue test before the high temperature test. And DCPD method was adopted to measure the crack length in the high temperature.

  5. The Effects of Funding Changes upon the Rate of Knowledge Growth in Algebraic and Differential Topology, 1955-75.

    Science.gov (United States)

    Cohn, Steven F.

    1986-01-01

    Discusses effects of funding variations upon the rate of knowledge growth in algebraic and differential topology. Results based on a marginal productivity model indicated that funding variations had little or no effect upon the rate of knowledge growth. Lists 150 of the field's most highly rated papers. (ML)

  6. Large artificial anisotropic growth rate in on-lattice simulation of obliquely deposited nanostructures

    Science.gov (United States)

    Tanto, B.; Doiron, C. F.; Lu, T.-M.

    2011-01-01

    On-lattice particle simulation is one of the most common types of Monte Carlo simulations used in studying the dynamics of film growth. We report the observation of a large artificial anisotropic growth rate variation owing to the fixed arrangement of particles in an on-lattice simulation of oblique angle deposition. This unexpectedly large anisotropy is not reported in previous literatures and substantially affects the simulation outcomes such as column angle and porosity, two of the most essential quantities in obliquely deposited nanostructures. The result of our finding is of interest to all on-lattice simulations in obliquely deposited films or nanostructures.

  7. FACTORS AFFECTING FATIGUE CRACK GROWTH RATES OF FIBER REINFORCED METAL LAMINATES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Based upon an analytical model for predicting the crack growth in fiber reinforced metal laminates (FRMLs), some factors affecting the fatigue crack growth rates of FRMLs were analyzed, including the lay-up of FRMLs, the modulus of the fibers, the residual stresses in FRMLs, the bonding strength and the shear modulus of the adhesive, etc.It was shown from the present analysis that the interface number of the laminates, the modulus of the fibers and the residual stresses in FRMLs have very great effects on the fatigue lives of FRMLs, but the effects of the bonding strength and the shear modulus of the adhesive are relatively small.

  8. Acoustically derived growth rates of sperm whales (Physeter macrocephalus) in Kaikoura, New Zealand.

    Science.gov (United States)

    Miller, Brian S; Growcott, Abraham; Slooten, Elisabeth; Dawson, Stephen M

    2013-09-01

    A non-invasive acoustic method for measuring the growth of sperm whales was developed based on estimating the length of individuals by measuring the inter-pulse interval (IPI) of their clicks. Most prior knowledge of growth in male sperm whales has come from from fitting growth curves to length data gained from whaling. Recordings made at Kaikoura, New Zealand, were used to estimate the length and growth of 32 photographically identified, resident whales that have been recorded repeatedly between 1991 and 2009. All whales recorded more than six months apart (n = 30) showed an increase in IPI. Using established relationships between IPI and total length, it was found that the average growth rate in the Kaikoura population is lower, especially for smaller whales (13-14.5 m), than that derived from historical whaling data from other populations. This difference may be due to ecological differences among populations but might also reflect upward bias in measurements gained in whaling. The ability to track growth of individuals through time is only possible via non-lethal means and offers a fundamentally different kind of data because differences among individuals can be measured.

  9. Growth rates of rhizosphere microorganisms depend on competitive abilities of plants for nitrogen

    Science.gov (United States)

    Blagodatskaya, Evgenia; Littschwager, Johanna; Lauerer, Marianna; Kuzyakov, Yakov

    2010-05-01

    Rhizosphere - one of the most important ‘hot spots' in soil - is characterized not only by accelerated turnover of microbial biomass and nutrients but also by strong intra- and inter-specific competition. Intra-specific competition occurs between individual plants of the same species, while inter-specific competition can occur both at population level (plant species-specific, microbial species-specific interactions) and at community level (plant - microbial interactions). Such plant - microbial interactions are mainly governed by competition for available N sources, since N is one of the main growth limiting nutrients in natural ecosystems. Functional structure and activity of microbial community in rhizosphere is not uniform and is dependent on quantity and quality of root exudates which are plant specific. It is still unclear how microbial growth and turnover in the rhizosphere are dependent on the features and competitive abilities of plants for N. Depending on C and N availability, acceleration and even retardation of microbial activity and carbon mineralization can be expected in the rhizosphere of plants with high competitive abilities for N. We hypothesized slower microbial growth rates in the rhizosphere of plants with smaller roots, as they usually produce less exudates compared to plants with small shoot-to-root ratio. As the first hypothesis is based solely on C availability, we also expected the greater effect of N availability on microbial growth in rhizosphere of plants with smaller root mass. These hypothesis were tested for two plant species of strawberry: Fragaria vesca L. (native species), and Duchesnea indica (Andrews) Focke (an invasive plant in central Europe) growing in intraspecific and interspecific competition. Microbial biomass and the kinetic parameters of microbial growth in the rhizosphere were estimated by dynamics of CO2 emission from the soil amended with glucose and nutrients. Specific growth rate (µ) of soil microorganisms was

  10. Analysis of internal doses to Mole voles inhabiting the East-Ural radioactive trace

    Energy Technology Data Exchange (ETDEWEB)

    Malinovsky, G.; Yarmoshenko, I. [Institute of Industrial Ecology UB RAS (Russian Federation); Chibiryak, M.; Vasil' ev, A. [Institute of Plant and Animal Ecology UB RAS (Russian Federation)

    2014-07-01

    Substantial task of development of approaches to radiation protection of non-human biota is investigation of relationships of exposure to dose, and dose to effects. Small mammals inhabiting territory of the East-Ural Radioactive Trace (EURT) are affected to ionizing radiation for many generations after accident at Mayak plutonium production in 1957. According to results of numerous studies a number of effects of exposure are observed. It is remarkable that the revealed effects are both negative and adaptive. In particular, the analysis of the variability of morphological structures of the axial skull and lower jaw in the population of northern mole vole (Ellobius talpinus Pall.), the burrowing rodent inhabiting the EURT, is of great interest. At the same time there is no reliable assessment of the radiation doses to these animals. Earlier we developed the approach to assess internal doses to mouse-like rodents (mice and voles) caused by incorporated {sup 90}Sr, which is the main dose contributing radionuclide at the EURT. Dose assessments are based on the results of beta-radiometry of intact bone. Routine methods for measuring the activity concentration of {sup 90}Sr in skeleton require ashing of samples, however in morphometric studies the destruction of material should be avoided: the skulls of mole voles are stored in the environmental samples depository of IPAE. Coefficients linking results of beta-radiometry of intact bone and activity concentration of {sup 90}Sr in skull of mouse was obtained basing on comparison of results of beta-radiometry of intact bone and bone ash. Obtained coefficients cannot be directly applied for calculating activity concentration of {sup 90}Sr in mole vole skulls because they are significantly larger. Therefore the additional study is required to assess proper coefficient of conversion from beta-radiometry to activity concentration of {sup 90}Sr. Developed dose assessment procedure includes application of the published values of

  11. Landscape features and helminth co-infection shape bank vole immunoheterogeneity, with consequences for Puumala virus epidemiology.

    Science.gov (United States)

    Guivier, E; Galan, M; Henttonen, H; Cosson, J-F; Charbonnel, N

    2014-03-01

    Heterogeneity in environmental conditions helps to maintain genetic and phenotypic diversity in ecosystems. As such, it may explain why the capacity of animals to mount immune responses is highly variable. The quality of habitat patches, in terms of resources, parasitism, predation and habitat fragmentation may, for example, trigger trade-offs ultimately affecting the investment of individuals in various immunological pathways. We described spatial immunoheterogeneity in bank vole populations with respect to landscape features and co-infection. We focused on the consequences of this heterogeneity for the risk of Puumala hantavirus (PUUV) infection. We assessed the expression of the Tnf-α and Mx2 genes and demonstrated a negative correlation between PUUV load and the expression of these immune genes in bank voles. Habitat heterogeneity was partly associated with differences in the expression of these genes. Levels of Mx2 were lower in large forests than in fragmented forests, possibly due to differences in parasite communities. We previously highlighted the positive association between infection with Heligmosomum mixtum and infection with PUUV. We found that Tnf-α was more strongly expressed in voles infected with PUUV than in uninfected voles or in voles co-infected with the nematode H. mixtum and PUUV. H. mixtum may limit the capacity of the vole to develop proinflammatory responses. This effect may increase the risk of PUUV infection and replication in host cells. Overall, our results suggest that close interactions between landscape features, co-infection and immune gene expression may shape PUUV epidemiology.

  12. Temperature dependence of metabolic rates for microbial growth, maintenance, and survival.

    Science.gov (United States)

    Price, P Buford; Sowers, Todd

    2004-03-30

    Our work was motivated by discoveries of prokaryotic communities that survive with little nutrient in ice and permafrost, with implications for past or present microbial life in Martian permafrost and Europan ice. We compared the temperature dependence of metabolic rates of microbial communities in permafrost, ice, snow, clouds, oceans, lakes, marine and freshwater sediments, and subsurface aquifer sediments. Metabolic rates per cell fall into three groupings: (i) a rate, microg(T), for growth, measured in the laboratory at in situ temperatures with minimal disturbance of the medium; (ii) a rate, microm(T), sufficient for maintenance of functions but for a nutrient level too low for growth; and (iii) a rate, micros(T), for survival of communities imprisoned in deep glacial ice, subsurface sediment, or ocean sediment, in which they can repair macromolecular damage but are probably largely dormant. The three groups have metabolic rates consistent with a single activation energy of approximately 110 kJ and that scale as microg(T):microm(T):micros(T) approximately 10(6):10(3):1. There is no evidence of a minimum temperature for metabolism. The rate at -40 degrees C in ice corresponds to approximately 10 turnovers of cellular carbon per billion years. Microbes in ice and permafrost have metabolic rates similar to those in water, soil, and sediment at the same temperature. This finding supports the view that, far below the freezing point, liquid water inside ice and permafrost is available for metabolism. The rate micros(T) for repairing molecular damage by means of DNA-repair enzymes and protein-repair enzymes such as methyltransferase is found to be comparable to the rate of spontaneous molecular damage.

  13. The Radial Growth Rate of Japanese Precious Corals Using Pb-210 Dating Method

    Science.gov (United States)

    Yamada, M.; Iwasaki, N.; Suzuki, A.; Aono, T.

    2014-12-01

    Precious corals belong to the subclass Octocorallia of the class Anthozoa. Its major component is calcium carbonate and the crystal structure is high-Mg calcite. Their skeletal axes are used for jewellery, rosary, amulet, etc. They are found mainly in the Japanese coast, the Mediterranean and off the Midway Islands and they are distributed at a depth of 100 m to 1500m. The growing skeletons of precious corals have potential for recording environmental change. Pb-210 is a naturally occurring radionuclide with a half-life of 22.3 years. Pb-210 is a natural sediment marker suitable for dating events that have occurred over the past 100 years and has been used to measure the sedimentation rates of lake and coastal marine sediments. The objectives of this study were to measure the Pb-210 concentration in the skeletons of Japanese red coral, pink coral and white coral and to estimate the radial growth rate using Pb-210 dating method. The radial growth rate of the skeleton can be estimated by the gradual decrease in Pb-210 concentrations measured from the surface inwards. The radial growth rate of the pink coral skeleton (Corallium elatius), collected at depths of 200 to 300 m off the coast of the Ryukyu Islands, Japan, was 0.15 mm/year, so slow that it would take as long as 50 years for a colony to grow to 15 mm in diameter.

  14. Growth rate of Heterobasidion annosum in Picea abies established on forest land and arable land

    Energy Technology Data Exchange (ETDEWEB)

    Bendz-Hellgren, M.; Johansson, Martin; Swedjemark, G.; Stenlid, J. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology; Brandtberg, P.O. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Ecology and Environmental Research

    1999-07-01

    The growth rates of Heterobasidion annosum in Norway spruce were investigated in southern Sweden. In one study, stump and tree roots in stands established on previous forest or arable land were inoculated with H. annosum-infested sawdust. After 1-3 yrs, the linear extent of colonization by the fungus was measured, based on detection of its conidiophores on incubated samples. The average growth rate was 25 cm yr{sup -1} in stump roots and 9 cm yr{sup -1} in tree roots, neither of which differed significantly between forest and arable land. The feeling of a decayed tree could enhance the spread of H. annosum within root systems. In the second study, the height of discoloration and extent of colonization by H. annosum, measured as above, were assessed in naturally infected trees. On average, discoloration moved through the roots and stem at a rate of 36 cm yr{sup -1}. Heterobasidion annosum was found 60 cm in advance of the discoloration, corresponding to a growth rate of 52 cm yr{sup -1}.

  15. Testing the growth rate hypothesis in vascular plants with above- and below-ground biomass.

    Science.gov (United States)

    Yu, Qiang; Wu, Honghui; He, Nianpeng; Lü, Xiaotao; Wang, Zhiping; Elser, James J; Wu, Jianguo; Han, Xingguo

    2012-01-01

    The growth rate hypothesis (GRH) proposes that higher growth rate (the rate of change in biomass per unit biomass, μ) is associated with higher P concentration and lower C:P and N:P ratios. However, the applicability of the GRH to vascular plants is not well-studied and few studies have been done on belowground biomass. Here we showed that, for aboveground, belowground and total biomass of three study species, μ was positively correlated with N:C under N limitation and positively correlated with P:C under P limitation. However, the N:P ratio was a unimodal function of μ, increasing for small values of μ, reaching a maximum, and then decreasing. The range of variations in μ was positively correlated with variation in C:N:P stoichiometry. Furthermore, μ and C:N:P ranges for aboveground biomass were negatively correlated with those for belowground. Our results confirm the well-known association of growth rate with tissue concentration of the limiting nutrient and provide empirical support for recent theoretical formulations.

  16. Testing the growth rate hypothesis in vascular plants with above- and below-ground biomass.

    Directory of Open Access Journals (Sweden)

    Qiang Yu

    Full Text Available The growth rate hypothesis (GRH proposes that higher growth rate (the rate of change in biomass per unit biomass, μ is associated with higher P concentration and lower C:P and N:P ratios. However, the applicability of the GRH to vascular plants is not well-studied and few studies have been done on belowground biomass. Here we showed that, for aboveground, belowground and total biomass of three study species, μ was positively correlated with N:C under N limitation and positively correlated with P:C under P limitation. However, the N:P ratio was a unimodal function of μ, increasing for small values of μ, reaching a maximum, and then decreasing. The range of variations in μ was positively correlated with variation in C:N:P stoichiometry. Furthermore, μ and C:N:P ranges for aboveground biomass were negatively correlated with those for belowground. Our results confirm the well-known association of growth rate with tissue concentration of the limiting nutrient and provide empirical support for recent theoretical formulations.

  17. Recent pause in the growth rate of atmospheric CO2 due to enhanced terrestrial carbon uptake

    Science.gov (United States)

    Keenan, Trevor F.; Prentice, I. Colin; Canadell, Josep G.; Williams, Christopher A.; Wang, Han; Raupach, Michael; Collatz, G. James

    2016-11-01

    Terrestrial ecosystems play a significant role in the global carbon cycle and offset a large fraction of anthropogenic CO2 emissions. The terrestrial carbon sink is increasing, yet the mechanisms responsible for its enhancement, and implications for the growth rate of atmospheric CO2, remain unclear. Here using global carbon budget estimates, ground, atmospheric and satellite observations, and multiple global vegetation models, we report a recent pause in the growth rate of atmospheric CO2, and a decline in the fraction of anthropogenic emissions that remain in the atmosphere, despite increasing anthropogenic emissions. We attribute the observed decline to increases in the terrestrial sink during the past decade, associated with the effects of rising atmospheric CO2 on vegetation and the slowdown in the rate of warming on global respiration. The pause in the atmospheric CO2 growth rate provides further evidence of the roles of CO2 fertilization and warming-induced respiration, and highlights the need to protect both existing carbon stocks and regions, where the sink is growing rapidly.

  18. Linking leaf veins to growth and mortality rates: an example from a subtropical tree community.

    Science.gov (United States)

    Iida, Yoshiko; Sun, I-Fang; Price, Charles A; Chen, Chien-Teh; Chen, Zueng-Sang; Chiang, Jyh-Min; Huang, Chun-Lin; Swenson, Nathan G

    2016-09-01

    A fundamental goal in ecology is to link variation in species function to performance, but functional trait-performance investigations have had mixed success. This indicates that less commonly measured functional traits may more clearly elucidate trait-performance relationships. Despite the potential importance of leaf vein traits, which are expected to be related to resource delivery rates and photosynthetic capacity, there are few studies, which examine associations between these traits and demographic performance in communities. Here, we examined the associations between species traits including leaf venation traits and demographic rates (Relative Growth Rate, RGR and mortality) as well as the spatial distributions of traits along soil environment for 54 co-occurring species in a subtropical forest. Size-related changes in demographic rates were estimated using a hierarchical Bayesian approach. Next, Kendall's rank correlations were quantified between traits and estimated demographic rates at a given size and between traits and species-average soil environment. Species with denser venation, smaller areoles, less succulent, or thinner leaves showed higher RGR for a wide range of size classes. Species with leaves of denser veins, larger area, cheaper construction costs or thinner, or low-density wood were associated with high mortality rates only in small size classes. Lastly, contrary to our expectations, acquisitive traits were not related to resource-rich edaphic conditions. This study shows that leaf vein traits are weakly, but significantly related to tree demographic performance together with other species traits. Because leaf traits associated with an acquisitive strategy such as denser venation, less succulence, and thinner leaves showed higher growth rate, but similar leaf traits were not associated with mortality, different pathways may shape species growth and survival. This study suggests that we are still not measuring some of key traits related to

  19. Structural growth trajectories and rates of change in the first 3 months of infant brain development.

    Science.gov (United States)

    Holland, Dominic; Chang, Linda; Ernst, Thomas M; Curran, Megan; Buchthal, Steven D; Alicata, Daniel; Skranes, Jon; Johansen, Heather; Hernandez, Antonette; Yamakawa, Robyn; Kuperman, Joshua M; Dale, Anders M

    2014-10-01

    The very early postnatal period witnesses extraordinary rates of growth, but structural brain development in this period has largely not been explored longitudinally. Such assessment may be key in detecting and treating the earliest signs of neurodevelopmental disorders. To assess structural growth trajectories and rates of change in the whole brain and regions of interest in infants during the first 3 months after birth. Serial structural T1-weighted and/or T2-weighted magnetic resonance images were obtained for 211 time points from 87 healthy term-born or term-equivalent preterm-born infants, aged 2 to 90 days, between October 5, 2007, and June 12, 2013. We segmented whole-brain and multiple subcortical regions of interest using a novel application of Bayesian-based methods. We modeled growth and rate of growth trajectories nonparametrically and assessed left-right asymmetries and sexual dimorphisms. Whole-brain volume at birth was approximately one-third of healthy elderly brain volume, and did not differ significantly between male and female infants (347 388 mm3 and 335 509 mm3, respectively, P = .12). The growth rate was approximately 1%/d, slowing to 0.4%/d by the end of the first 3 months, when the brain reached just more than half of elderly adult brain volume. Overall growth in the first 90 days was 64%. There was a significant age-by-sex effect leading to widening separation in brain sizes with age between male and female infants (with male infants growing faster than females by 200.4 mm3/d, SE = 67.2, P = .003). Longer gestation was associated with larger brain size (2215 mm3/d, SE = 284, P = 4×10-13). The expected brain size of an infant born one week earlier than average was 5% smaller than average; at 90 days it will not have caught up, being 2% smaller than average. The cerebellum grew at the highest rate, more than doubling in 90 days, and the hippocampus grew at the slowest rate, increasing by 47% in 90 days. There was left

  20. Are Methods for Estimating Primary Production and the Growth Rates of Phytoplankton Approaching Agreement?

    Science.gov (United States)

    Cullen, J. J.

    2016-02-01

    During the 1980s, estimates of primary productivity and the growth rates of phytoplankton in oligotrophic waters were controversial, in part because rates based on seasonal accumulations of oxygen in the shallow oxygen maximum were reported to be much higher than could be accounted for with measurements of photosynthesis based on incubations with C-14. Since then, much has changed: tested and standardized methods have been employed to collect comprehensive time-series observations of primary production and related oceanographic properties in oligotrophic waters of the North Pacific subtropical gyre and the Sargasso Sea; technical and theoretical advances have led to new tracer-based estimates of photosynthesis (e.g., oxygen/argon and triple isotopes of dissolved oxygen); and biogeochemical sensor systems on ocean gliders and profiling floats can describe with unprecedented resolution the dynamics of phytoplankton, oxygen and nitrate as driven by growth, loss processes including grazing, and vertical migration for nutrient acquisition. Meanwhile, the estimation of primary productivity, phytoplankton biomass and phytoplankton growth rates from remote sensing of ocean color has matured, complementing biogeochemical models that describe and predict these key properties of plankton dynamics. In a selective review focused on well-studied oligotrophic waters, I compare methods for estimating the primary productivity and growth rates of phytoplankton to see if they are converging on agreement, not only in the estimated rates, but also in the underlying assumptions, such as the ratio of gross- to net primary production — and how this relates to the measurement — and the ratio of chlorophyll to carbon in phytoplankton. Examples of agreement are encouraging, but some stark contrasts illustrate the need for improved mechanistic understanding of exactly what each method is measuring.

  1. Survival, Recruitment, and Population Growth Rate of an Important Mesopredator: The Northern Raccoon

    Science.gov (United States)

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

    2014-01-01

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

  2. Lyapunov Exponent and Out-of-Time-Ordered Correlator's Growth Rate in a Chaotic System.

    Science.gov (United States)

    Rozenbaum, Efim B; Ganeshan, Sriram; Galitski, Victor

    2017-02-24

    It was proposed recently that the out-of-time-ordered four-point correlator (OTOC) may serve as a useful characteristic of quantum-chaotic behavior, because, in the semiclassical limit ℏ→0, its rate of exponential growth resembles the classical Lyapunov exponent. Here, we calculate the four-point correlator C(t) for the classical and quantum kicked rotor-a textbook driven chaotic system-and compare its growth rate at initial times with the standard definition of the classical Lyapunov exponent. Using both quantum and classical arguments, we show that the OTOC's growth rate and the Lyapunov exponent are, in general, distinct quantities, corresponding to the logarithm of the phase-space averaged divergence rate of classical trajectories and to the phase-space average of the logarithm, respectively. The difference appears to be more pronounced in the regime of low kicking strength K, where no classical chaos exists globally. In this case, the Lyapunov exponent quickly decreases as K→0, while the OTOC's growth rate may decrease much slower, showing a higher sensitivity to small chaotic islands in the phase space. We also show that the quantum correlator as a function of time exhibits a clear singularity at the Ehrenfest time t_{E}: transitioning from a time-independent value of t^{-1}lnC(t) at tt_{E}. We note that the underlying physics here is the same as in the theory of weak (dynamical) localization [Aleiner and Larkin, Phys. Rev. B 54, 14423 (1996)PRBMDO0163-182910.1103/PhysRevB.54.14423; Tian, Kamenev, and Larkin, Phys. Rev. Lett. 93, 124101 (2004)PRLTAO0031-900710.1103/PhysRevLett.93.124101] and is due to a delay in the onset of quantum interference effects, which occur sharply at a time of the order of the Ehrenfest time.

  3. Lyapunov Exponent and Out-of-Time-Ordered Correlator's Growth Rate in a Chaotic System

    Science.gov (United States)

    Rozenbaum, Efim B.; Ganeshan, Sriram; Galitski, Victor

    2017-02-01

    It was proposed recently that the out-of-time-ordered four-point correlator (OTOC) may serve as a useful characteristic of quantum-chaotic behavior, because, in the semiclassical limit ℏ→0 , its rate of exponential growth resembles the classical Lyapunov exponent. Here, we calculate the four-point correlator C (t ) for the classical and quantum kicked rotor—a textbook driven chaotic system—and compare its growth rate at initial times with the standard definition of the classical Lyapunov exponent. Using both quantum and classical arguments, we show that the OTOC's growth rate and the Lyapunov exponent are, in general, distinct quantities, corresponding to the logarithm of the phase-space averaged divergence rate of classical trajectories and to the phase-space average of the logarithm, respectively. The difference appears to be more pronounced in the regime of low kicking strength K , where no classical chaos exists globally. In this case, the Lyapunov exponent quickly decreases as K →0 , while the OTOC's growth rate may decrease much slower, showing a higher sensitivity to small chaotic islands in the phase space. We also show that the quantum correlator as a function of time exhibits a clear singularity at the Ehrenfest time tE: transitioning from a time-independent value of t-1ln C (t ) at t tE. We note that the underlying physics here is the same as in the theory of weak (dynamical) localization [Aleiner and Larkin, Phys. Rev. B 54, 14423 (1996), 10.1103/PhysRevB.54.14423; Tian, Kamenev, and Larkin, Phys. Rev. Lett. 93, 124101 (2004), 10.1103/PhysRevLett.93.124101] and is due to a delay in the onset of quantum interference effects, which occur sharply at a time of the order of the Ehrenfest time.

  4. Biomedical progress rates as new parameters for models of economic growth in developed countries.

    Science.gov (United States)

    Zhavoronkov, Alex; Litovchenko, Maria

    2013-11-08

    While the doubling of life expectancy in developed countries during the 20th century can be attributed mostly to decreases in child mortality, the trillions of dollars spent on biomedical research by governments, foundations and corporations over the past sixty years are also yielding longevity dividends in both working and retired population. Biomedical progress will likely increase the healthy productive lifespan and the number of years of government support in the old age. In this paper we introduce several new parameters that can be applied to established models of economic growth: the biomedical progress rate, the rate of clinical adoption and the rate of change in retirement age. The biomedical progress rate is comprised of the rejuvenation rate (extending the productive lifespan) and the non-rejuvenating rate (extending the lifespan beyond the age at which the net contribution to the economy becomes negative). While staying within the neoclassical economics framework and extending the overlapping generations (OLG) growth model and assumptions from the life cycle theory of saving behavior, we provide an example of the relations between these new parameters in the context of demographics, labor, households and the firm.

  5. Biomedical Progress Rates as New Parameters for Models of Economic Growth in Developed Countries

    Directory of Open Access Journals (Sweden)

    Alex Zhavoronkov

    2013-11-01

    Full Text Available While the doubling of life expectancy in developed countries during the 20th century can be attributed mostly to decreases in child mortality, the trillions of dollars spent on biomedical research by governments, foundations and corporations over the past sixty years are also yielding longevity dividends in both working and retired population. Biomedical progress will likely increase the healthy productive lifespan and the number of years of government support in the old age. In this paper we introduce several new parameters that can be applied to established models of economic growth: the biomedical progress rate, the rate of clinical adoption and the rate of change in retirement age. The biomedical progress rate is comprised of the rejuvenation rate (extending the productive lifespan and the non-rejuvenating rate (extending the lifespan beyond the age at which the net contribution to the economy becomes negative. While staying within the neoclassical economics framework and extending the overlapping generations (OLG growth model and assumptions from the life cycle theory of saving behavior, we provide an example of the relations between these new parameters in the context of demographics, labor, households and the firm.

  6. Iron and Multivitamin Supplements in Children and its Association with Growth rate

    Directory of Open Access Journals (Sweden)

    Masumeh Saeidi

    2013-12-01

    Full Text Available Introduction: Vitamin deficiency and iron deficiency anemia are common nutritional problems, at least in children under 5. These materials shortage, especially in the first two years of life, impair physical and brain growth, reduces the child's learning ability, reduces body resistance against infections, behavioral changes, apathy and finally social and economic adverse consequences would be followed. This study aimed to determine the supplements used in children under two years and its Association with Growth rate in Mashhad City.   Materials and Methods: In this cross-sectional descriptive study , 300 children 6 to 24 months were recruited in health centers in Mashhad, Data was collected from mother and and children’ records and valid and reliable  questionnaire was used to collect data. The data was analyzed by statistical tests and SPSS 11.5 and P  Results: Results showed that 13.7 percent of families were with low income, 82.7 percent middle income and 3.7 percent well income. In growth chart, 86.7 percent of children showed appropriate growth, 10.3 percent had delayed growth and 3 percent had horizontal growth curve .In 80.7 percent of families, maternal multivitamin and iron drops have been used to their children regularly, 1.7 percent did not believe in these supplements and 17.7 percent of mothers sometimes used these supplements for their children. Results also showed statistical correlation significant variables of parental education, family income, mothers referred to health centers for monitoring the growth and get face to face training of personnel center drops of multivitamin with iron and growth status of children variable is available, so children who regularly have used supplements and income level and above are literate parents have grown more favorable than the other kids (P

  7. Postnatal growth rates covary weakly with embryonic development rates and do not explain adult mortality probability among songbirds on four continents

    Science.gov (United States)

    Martin, Thomas E.; Oteyza, Juan C.; Mitchell, Adam E.; Potticary, Ahva L.; Lloyd, P.

    2016-01-01

    Growth and development rates may result from genetic programming of intrinsic processes that yield correlated rates between life stages. These intrinsic rates are thought to affect adult mortality probability and longevity. However, if proximate extrinsic factors (e.g., temperature, food) influence development rates differently between stages and yield low covariance between stages, then development rates may not explain adult mortality probability. We examined these issues based on study of 90 songbird species on four continents to capture the diverse life-history strategies observed across geographic space. The length of the embryonic period explained little variation (ca. 13%) in nestling periods and growth rates among species. This low covariance suggests that the relative importance of intrinsic and extrinsic influences on growth and development rates differs between stages. Consequently, nestling period durations and nestling growth rates were not related to annual adult mortality probability among diverse songbird species within or among sites. The absence of a clear effect of faster growth on adult mortality when examined in an evolutionary framework across species may indicate that species that evolve faster growth also evolve physiological mechanisms for ameliorating costs on adult mortality. Instead, adult mortality rates of species in the wild may be determined more strongly by extrinsic environmental causes.

  8. Stiff mutant genes of phycomyces affect turgor pressure and wall mechanical properties to regulate elongation growth rate.

    Science.gov (United States)

    Ortega, Joseph K E; Munoz, Cindy M; Blakley, Scott E; Truong, Jason T; Ortega, Elena L

    2012-01-01

    Regulation of cell growth is paramount to all living organisms. In plants, algae and fungi, regulation of expansive growth of cells is required for development and morphogenesis. Also, many sensory responses of stage IVb sporangiophores of Phycomyces blakesleeanus are produced by regulating elongation growth rate (growth responses) and differential elongation growth rate (tropic responses). "Stiff" mutant sporangiophores exhibit diminished tropic responses and are found to be defective in at least five genes; madD, E, F, G, and J. Prior experimental research suggests that the defective genes affect growth regulation, but this was not verified. All the growth of the single-celled stalk of the stage IVb sporangiophore occurs in a short region termed the "growth zone." Prior experimental and theoretical research indicates that elongation growth rate of the stage IVb sporangiophore can be regulated by controlling the cell wall mechanical properties within the growth zone and the magnitude of the turgor pressure. A quantitative biophysical model for elongation growth rate is required to elucidate the relationship between wall mechanical properties and turgor pressure during growth regulation. In this study, it is hypothesized that the mechanical properties of the wall within the growth zone of stiff mutant sporangiophores are different compared to wild type (WT). A biophysical equation for elongation growth rate is derived for fungal and plant cells with a growth zone. Two strains of stiff mutants are studied, C149 madD120 (-) and C216 geo- (-). Experimental results demonstrate that turgor pressure is larger but irreversible wall deformation rates within the growth zone and growth zone length are smaller for stiff mutant sporangiophores compared to WT. These findings can explain the diminished tropic responses of the stiff mutant sporangiophores. It is speculated that the defective genes affect the amount of wall-building material delivered to the inner cell wall.

  9. 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.)

  10. Effect of cold work on the growth rates of stress corrosion cracks in structural materials of nuclear systems

    Energy Technology Data Exchange (ETDEWEB)

    Magdowski, R.; Speidel, M.O. [Swiss Federal Inst. of Tech., Zurich (Switzerland). Inst. of Metallurgy

    1996-10-01

    The growth rates of stress corrosion cracks in austenitic stainless steels and nickel base alloy 600 exposed to simulated boiling water reactor coolant were measured by fracture mechanics testing techniques. Cold work may increase the crack growth rates up to one hundred times. In both, the annealed condition and the cold worked condition, the stress corrosion crack growth rates are independent of stress intensity over a wide K-range and crack growth rates correlate well with yield strength and hardness. In the annealed condition the fracture path is intergranular, but higher degrees of cold work introduce higher proportions of transgranular stress corrosion cracking.

  11. Bacteriophage T4 development in Escherichia coli is growth rate dependent.

    Science.gov (United States)

    Rabinovitch, Avinoam; Fishov, Itzhak; Hadas, Hilla; Einav, Monica; Zaritsky, Arieh

    2002-05-01

    Three independent parameters (eclipse and latent periods, and rate of ripening during the rise period) are essential and sufficient to describe bacteriophage development in its bacterial host. A general model to describe the classical "one-step growth" experiment [Rabinovitch et al. (1999a) J. Bacteriol.181, 1687-1683] allowed their calculations from experimental results obtained with T4 in Escherichia coli B/r under different growth conditions [Hadas et al. (1997) Microbiology143, 179-185]. It is found that all three parameters could be described by their dependence solely on the culture doubling time tau before infection. Their functional dependence on tau, derived by a best-fit analysis, was used to calculate burst size values. The latter agree well with the experimental results. The dependence of the derived parameters on growth conditions can be used to predict phage development under other experimental manipulations.

  12. Automatic Evaluation of Colonies Growth rate of Yeasts incubated in Petri dishes using Mobile Platform

    Directory of Open Access Journals (Sweden)

    Alecsander Pereira Martins

    2015-10-01

    Full Text Available This paper proposes an automatic method based on computer vision implemented in mobile platform capable of monitoring the growth of microbial colonies incubated in Petri dishes. The developed optimized image processing algorithm performs this task without human intervention from images of colonies of the microorganism in different evolution phases. The contribution of this paper is the development of a fast and robust mobile tool to assist bioprocess experts in monitoring the growth of colonies without using the conventional error prone evaluation techniques. The obtained results successfully demonstrated dimensional alterations in colonies in a faster and more precise fashion when compared with the conventional method, with the additional advantage of versatility in producing reliable estimation of the growth rates with higher statistical significance.

  13. The effect of growth rate and ageing on colour variation of European pond turtles

    Science.gov (United States)

    Ibáñez, Alejandro; Martín, José; Marzal, Alfonso; Bertolero, Albert

    2017-06-01

    Many chelonians have colourful dots, patches and stripes throughout their body that are made up, at least in part, of carotenoids. Therefore, turtles are very suitable models to study the evolution and functionality of carotenoid-based colouration. Recent studies suggested a close link between colouration and immune system in these taxa. However, more research is needed to understand the role of these colourful stripes and patches in turtle visual signalling. The purpose of this study was to explore the relationship between growth rate and colouration in European pond turtles. In particular, we wanted to answer the question of whether there is a trade-off between growth and colour expression. We also aimed to explore the effect of body size and age on colour variation. Turtles from a reintroduction-breeding program were recaptured, weighed and measured over an 8-year period to estimate their growth rates and age. We also measured with a spectrometer the reflectance of colour patches in two different body parts: shell and forelimb. We found that turtles with a faster growth rate had brighter limb stripes independently of their age. On the other hand, shell colouration was related to body size with larger turtles having brighter shell stripes and higher values of carotenoid chroma. Our results suggest that fast-growers may afford to express intense colourful limb stripes likely due to their higher intake of carotenoids that would modulate both growth and colour expression. However, shell colouration was related to body size probably due to ontogenetic differences in the diet, as juveniles are strictly carnivorous while adults are omnivorous. Alternatively, shell colouration might be involved in crypsis as the shell is visually exposed to predators.

  14. Adult survival and population growth rate in Colorado big brown bats (Eptesicus fuscus)

    Science.gov (United States)

    O'Shea, T.J.; Ellison, L.E.; Stanley, T.R.

    2011-01-01

    We studied adult survival and population growth at multiple maternity colonies of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado. We investigated hypotheses about survival using information-theoretic methods and mark-recapture analyses based on passive detection of adult females tagged with passive integrated transponders. We constructed a 3-stage life-history matrix model to estimate population growth rate (??) and assessed the relative importance of adult survival and other life-history parameters to population growth through elasticity and sensitivity analysis. Annual adult survival at 5 maternity colonies monitored from 2001 to 2005 was estimated at 0.79 (95% confidence interval [95% CI] = 0.77-0.82). Adult survival varied by year and roost, with low survival during an extreme drought year, a finding with negative implications for bat populations because of the likelihood of increasing drought in western North America due to global climate change. Adult survival during winter was higher than in summer, and mean life expectancies calculated from survival estimates were lower than maximum longevity records. We modeled adult survival with recruitment parameter estimates from the same population. The study population was growing (?? = 1.096; 95% CI = 1.057-1.135). Adult survival was the most important demographic parameter for population growth. Growth clearly had the highest elasticity to adult survival, followed by juvenile survival and adult fecundity (approximately equivalent in rank). Elasticity was lowest for fecundity of yearlings. The relative importances of the various life-history parameters for population growth rate are similar to those of large mammals. ?? 2011 American Society of Mammalogists.

  15. Speed over efficiency: locusts select body temperatures that favour growth rate over efficient nutrient utilization

    DEFF Research Database (Denmark)

    Miller, Gabriel A; Clissold, Fiona J; Mayntz, David

    2009-01-01

    to investigate relationships between growth/development and macronutrient utilization (conversion of ingesta to body mass) as a function of temperature. A range of macronutrient intake values for insects at 26, 32 and 38°C was achieved by offering individuals high-protein diets, high-carbohydrate diets......Ectotherms have evolved preferences for particular body temperatures, but the nutritional and life-history consequences of such temperature preferences are not well understood. We measured thermal preferences in Locusta migratoria (migratory locusts) and used a multi-factorial experimental design...... or a choice between both. Locusts placed in a thermal gradient selected temperatures near 38°C, maximizing rates of weight gain; however, this enhanced growth rate came at the cost of poor protein and carbohydrate utilization. Protein and carbohydrate were equally digested across temperature treatments...

  16. TEST OF THE CATCH-UP HYPOTHESIS IN AFRICAN AGRICULTURAL GROWTH RATES

    Directory of Open Access Journals (Sweden)

    Kalu Ukpai IFEGWU

    2015-11-01

    Full Text Available The paper tested the catch-up hypothesis in agricultural growth rates of twenty-six African countries. Panel data used was drawn from the Food and Agricultural Organization Statistics (FAOSTAT of the United Nations. The Data Envelopment Analysis Method for measuring productivity was used to estimate productivity growth rates. The cross-section framework consisting of sigma-convergence and beta-convergence was employed to test the catching up process. Catching up is said to exist if the value of beta is negative and significant. Since catching up does not necessarily imply narrowing of national productivity inequalities, sigma-convergence which measures inequality, was estimated for the same variables. The results showed evidence of the catch-up process, but failed to find a narrowing of productivity inequalities among countries.

  17. LOW ENDOPHTHALMITIS RATES AFTER INTRAVITREAL ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR INJECTIONS IN AN OPERATION ROOM

    DEFF Research Database (Denmark)

    Freiberg, Florentina J; Brynskov, Troels; Munk, Marion R

    2017-01-01

    PURPOSE: To evaluate the rate of presumed endophthalmitis (EO) after intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections in three European hospitals performed in an operation room (OR) under sterile conditions. METHODS: A retrospective multicenter study between 2003 and 2016...... at three European sites, City Hospital Triemli Zurich, Switzerland (CHT), Zealand University Hospital Roskilde, Denmark (ZUH) and University Clinic Bern, Switzerland (UCB). Intravitreal injection (IVI) database of each department was reviewed. All anti-vascular endothelial growth factor injections were.......0074% per injection (95% CI: 0.0070-0.0078%). Positive cultures were found in 4 out of 10 presumed endophthalmitis cases. CONCLUSION: The standardized sterile technique in an operation room with laminar airflow showed very low rates of endophthalmitis at three European sites....

  18. Drift Mode Growth Rate and Associated Ion Thermal Transport in Reversed Magnetic Shear Tokamak Plasma

    Institute of Scientific and Technical Information of China (English)

    WANG Ai-Ke; QIU Xiao-Ming

    2001-01-01

    Drift mode linear growth rate and quasi-linear ion thermal transport in the reversed magnetic shear plasma are investigated by using the two-fluid theory, previously developed by Weiland and the Chalmers group [J. Nucl.Fusion, 29 (1989) 1810; ibid. 30 (1990) 983]. The theory is here extended to include both the radial electrical field shear (dEr/dr) and the electron fluid velocity (Ve) in the sheared coordinate system. Here, Ve describes the coupling between the safety factor q and the Er × B velocity V E. Their influences on the growth rate and associated ion thermal transport are obtained numerically. In addition, the ion heat pinch in the reversed shear plasma is observed. Qualitatively, the present conclusions are in good agreement with the experimental results.

  19. Plasma effects on fast pair beams. III. Oblique electrostatic growth rates for perpendicular Maxwellian pair beams

    Energy Technology Data Exchange (ETDEWEB)

    Supsar, Markus; Schlickeiser, Reinhard, E-mail: markus.supsar@tp4.rub.de, E-mail: rsch@tp4.rub.de [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

    2014-03-10

    The distant universe is opaque to γ radiation from blazars due to gamma-gamma attenuation with extragalactic background light. This process produces electron-positron pair beams that interact with the intergalactic medium and are unstable to linear instabilities, particularly the electrostatic and Weibel instabilities. The electrostatic instability grows faster and so determines the dissipation of the free energy of the beam. Here, we generalize the calculation of the electrostatic growth rate to a beam plasma system with a Maxwellian perpendicular momentum spread and allow for oblique propagation directions. We show that the growth rate for the oblique electrostatic mode has a maximum value that is even higher than for a cold beam or for one with a constant perpendicular momentum spread.

  20. Essential growth rate for bounded linear perturbation of non-densely defined Cauchy problems

    Science.gov (United States)

    Ducrot, A.; Liu, Z.; Magal, P.

    2008-05-01

    This paper is devoted to the study of the essential growth rate of some class of semigroup generated by bounded perturbation of some non-densely defined problem. We extend some previous results due to Thieme [H.R. Thieme, Quasi-compact semigroups via bounded perturbation, in: Advances in Mathematical Population Dynamics--Molecules, Cells and Man, Houston, TX, 1995, in: Ser. Math. Biol. Med., vol. 6, World Sci. Publishing, River Edge, NJ, 1997, pp. 691-711] to a class of non-densely defined Cauchy problems in Lp. In particular in the context the integrated semigroup is not operator norm locally Lipschitz continuous. We overcome the lack of Lipschitz continuity of the integrated semigroup by deriving some weaker properties that are sufficient to give information on the essential growth rate.

  1. Fatigue Crack Growth Rate of Type 347 Stainless Steel at the PWR Environment

    Energy Technology Data Exchange (ETDEWEB)

    Min, Ki Deuk; Kim, Seon Jin [Hanyang University, Seoul (Korea, Republic of); Kim, Dae Whan; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-10-15

    Materials used in nuclear power plants are low alloy steel, stainless steel, and superalloy steel. Understanding the characteristics of these materials is important in the development of nuclear power plant related technology. Nb-stabilized Type 347 stainless steel is used for the coolant pressurizer surge line of Korea Standard Nuclear Power Plant (KSNPP). Surge line of PWR nuclear reactor are damaged by thermal fatigue due to thermal gradient during heat-up and cool-down, mechanical fatigue due to mechanical stress, and corrosion fatigue due to nuclear reactor water environment. Fatigue is an important factor which limits the life of structure. Fatigue crack growth rate curves in nuclear reactor environment are needed to evaluate the integrity of nuclear reactor structure but that result is not sufficient. In this study, fatigue crack growth rates at nuclear reactor environment are produced to evaluate integrity of nuclear power plant section 5

  2. PROBABILISTIC MODELS FOR LONG FATIGUE CRACK GROWTH RATES OF LZ50 AXLE STEEL

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yong-xiang; HE Chao-ming; YANG Bing; HUANG Yu-zhong; GAO Qing; WU Ping-bo

    2005-01-01

    Experimental study is performed on the probabilistic models for the long fatigue crack growth rates (da/dN) of LZ50 axle steel. An equation for crack growth rate was derived to consider the trend of stress intensity factor range going down to the threshold and the average stress effect. The probabilistic models were presented on the equation. They consist of the probabilistic da/dN-△K relations, the confidence-based da/dN-△K relations, and the probabilistic- and confidence-based da/dN-△K relations.Efforts were made respectively to characterize the effects of probabilistic assessments due to the scattering regularity of test data, the number of sampling, and both of them.These relations can provide wide selections for practice. Analysis on the test data of LZ50 steel indicates that the present models are available and feasible.

  3. Wavy membranes and the growth rate of a planar chemical garden: Enhanced diffusion and bioenergetics.

    Science.gov (United States)

    Ding, Yang; Batista, Bruno; Steinbock, Oliver; Cartwright, Julyan H E; Cardoso, Silvana S S

    2016-08-16

    To model ion transport across protocell membranes in Hadean hydrothermal vents, we consider both theoretically and experimentally the planar growth of a precipitate membrane formed at the interface between two parallel fluid streams in a 2D microfluidic reactor. The growth rate of the precipitate is found to be proportional to the square root of time, which is characteristic of diffusive transport. However, the dependence of the growth rate on the concentrations of hydroxide and metal ions is approximately linear and quadratic, respectively. We show that such a difference in ionic transport dynamics arises from the enhanced transport of metal ions across a thin gel layer present at the surface of the precipitate. The fluctuations in transverse velocity in this wavy porous gel layer allow an enhanced transport of the cation, so that the effective diffusivity is about one order of magnitude higher than that expected from molecular diffusion alone. Our theoretical predictions are in excellent agreement with our laboratory measurements of the growth of a manganese hydroxide membrane in a microfluidic channel, and this enhanced transport is thought to have been needed to account for the bioenergetics of the first single-celled organisms.

  4. Status and trend of tree growth and mortality rate at the CONECOFOR plots, 1997-2004

    Directory of Open Access Journals (Sweden)

    Gianfranco Fabbio

    2013-11-01

    Full Text Available The circumference of trees in the CONECOFOR permanent monitoring plots (PMPs were measured by three surveys carried out in 1997, 2000 and 2005. Plots were arranged into forest types according to tree species, management system and stand structure: beech (Fagus sylvatica L. and spruce (Picea abies K. high forests, aged coppice forests and transitory crops (deciduous, evergreen oaks and beech. Diameter distribution, basal area, basal area increment, tree mortality rate and in-growth were calculated per layer (dominant, intermediate, dominated within each PMP, to point out relative contributions and changes. A range in relative annual growth was detected both within and between types over the monitored period, but an obvious reduction of annual increment was found in two/thirds of plots over 2000-04 as compared to 1997-99. Current mortality, mostly allocated into the dominated and intermediate layers, can be explained as “regular” due to overstocking and high inter-tree competition in almost all of the observed case-studies. Opposite patterns were found to occur as for stand growth vs. mortality rate between coppice forests and the other types owing to the different dynamics of tree competition in progress. Drought 2003 is the likely large-scale factor determining the reduced annual growth course over the second period.

  5. Enhancement of the Initial Growth Rate of Agricultural Plants by Using Static Magnetic Fields.

    Science.gov (United States)

    Kim, Seung C; Mason, Alex; Im, Wooseok

    2016-07-08

    Electronic devices and high-voltage wires induce magnetic fields. A magnetic field of 1,300-2,500 Gauss (0.2 Tesla) was applied to Petri dishes containing seeds of Garden Balsam (Impatiens balsamina), Mizuna (Brassica rapa var. japonica), Komatsuna (Brassica rapa var. perviridis), and Mescluns (Lepidium sativum). We applied magnets under the culture dish. During the 4 days of application, we observed that the stem and root length increased. The group subjected to magnetic field treatment (n = 10) showed a 1.4 times faster rate of growth compared with the control group (n = 11) in a total of 8 days (p abnormal arrangements. However, the exact cause remains unclear. These results of growth enhancement of applying magnets suggest that it is possible to enhance the growth rate, increase productivity, or control the speed of germination of plants by applying static magnetic fields. Also, magnetic fields can cause physiological changes in plant cells and can induce growth. Therefore, stimulation with a magnetic field can have possible effects that are similar to those of chemical fertilizers, which means that the use of fertilizers can be avoided.

  6. A study on Haemophilus influenzae type b growth rate and capsule production in different media

    Directory of Open Access Journals (Sweden)

    Afshar, M.

    2012-06-01

    Full Text Available to compare growth rate and capsule production. Four liquid media namely brain heart infusion broth (BHI, trypticase soy broth (TSB, Mueller Hinton Broth (MHB and Gonococci broth (GC with added supplements (1% hemoglobin, 1% Isovitalex were used. The growth was measured by colony counting (CFU/ml using serial dilution. Four of the isolates showed the highest growth rate with the average of 1013 CFU/ml on BHI broth while TSB had the second highest growth of more than 1010 CFU/ml in an 18-hour culture at 37 ºC culture. In the next step, the amount of capsular polysaccharide (CPS-b antigen which is made of Polyribosyl ribitol phosphate (PRP was assessed all isolates by two methods: modified Indirect Sandwich Enzyme-linked immunosorbent assay (ELISA and Bial method to select the isolate producing the highest amount of PRP. The antisera used in sandwich ELISA were prepared by immunization of Rabbit and Rat. The maximal amount of PRP was produced by isolate Hib (5s with the amount of 321 mg/lit.

  7. Prediction of cavity growth rate during underground coal gasification using multiple regression analysis

    Institute of Scientific and Technical Information of China (English)

    Mehdi Najafi; Seyed Mohammad Esmaiel Jalali; Reza KhaloKakaie; Farrokh Forouhandeh

    2015-01-01

    During underground coal gasification (UCG), whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate (CGR) or the moving rate of the gasification face is affected by controllable (operation pressure, gasification time, geometry of UCG panel) and uncontrollable (coal seam properties) factors. The CGR is usually predicted by mathematical models and laboratory experiments, which are time consuming, cumbersome and expensive. In this paper, a new simple model for CGR is developed using non-linear regression analysis, based on data from 11 UCG field trials. The empirical model compares satisfactorily with Perkins model and can reliably predict CGR.

  8. Productivity dynamics of Livestock in southern peninsular India: A Compound growth rate analysis

    Directory of Open Access Journals (Sweden)

    G. Kathiravan 1 and S. Selvam 2

    2011-04-01

    Full Text Available Although India possesses the large volume of livestock, their productivity is abysmally low at global level. India, with its wide variation in geo-ecological parameters, elucidates a high variation in the productivity of its livestock, among regions. The compound growth rate of livestock productivity was worked out for the Southern Peninsular state of India, Tamil Nadu. The average productivity of milk in cross bred cows and buffaloes in Tamil Nadu was less than the national average, while the productivity desi cows was a bit a more. The annual compound growth rate of milk productivity among crossbred cows of Tamil Nadu was at meager 0.54 per cent during the period between 1998-1999 and 2006- 2007, whereas the productivity of milk in desi cows had improved from at an annual compound growth rate of 1.29 per cent. Notably, the milk productivity in buffaloes had declined at a rate of 0.29 per cent during the period under study. The annual compound growth of egg productivity in improved hens of Tamil Nadu was 20.87 per cent. The average annual productivity was 109.531 eggs, which improved from 70.623 in 1998-1999 to 197.084 in 2004-2005. Correspondingly, the productivity of desi hens also had a positive swing from the year 2003-2004 onwards. The results implied that the simulation of increased productivity, better farm financing and improved milk marketing could result in enhanced livestock production that would meet the future demands. [Veterinary World 2011; 4(2.000: 68-74

  9. Behavioural models of population growth rates: implications for conservation and prediction.

    OpenAIRE

    Sutherland, William J.; Norris, Ken

    2002-01-01

    Conservation biologists often wish to predict how vertebrate populations will respond to local or global changes in conditions such as those resulting from sea-level rise, deforestation, exploitation, genetically modified crops, global warming, human disturbance or from conservation activities. Predicting the consequences of such changes almost always requires understanding the population growth rate and the density dependence. Traditional means of directly measuring density dependence are of...

  10. A methodology to study cyclic debond growth at constant mode-mixity and energy release rate

    DEFF Research Database (Denmark)

    Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

    2010-01-01

    It is well known that face/core debond crack propagation is governed by the critical energy release rate (fracture toughness) and mode-mixity at the crack tip. Thus, the current study focuses on the developing of a methodology to perform fatigue crack growth experiments of debonded sandwich...... and better control of loading conditions at the crack tip will be the most relevant outcomes of using the proposed fatigue test method....

  11. Genome Size Is a Strong Predictor of Root Meristem Growth Rate

    OpenAIRE

    Adam Gruner; Nathan Hoverter; Tylia Smith; Charles A. Knight

    2010-01-01

    Variation in genome size (GS) has been linked to several facets of the plant phenotype. Recently it was shown that GS is significantly correlated with cell size and the duration of the cell cycle. Here we test the hypothesis that GS might also be a predictor of apical root meristem growth rate (RMGR). We studied eight species of eudicots with varying GS using time-lapse microscopic image analysis. A significant negative exponential relationship was observed between GS and RMGR. Our results sh...

  12. Influence of body temperature on bacterial growth rates in experimental pneumococcal meningitis in rabbits.

    OpenAIRE

    Small, P M; Täuber, M G; Hackbarth, C J; Sande, M A

    1986-01-01

    We examined the role of fever as a host defense in experimental pneumococcal meningitis in rabbits. Twelve hours after intracisternal inoculation of an encapsulated type 3 Streptococcus pneumoniae strain, body temperature was manipulated by using two different anesthetic drugs: pentobarbital, which did not affect temperature, and urethane, which mitigated the febrile response to infection. Growth rates of pneumococci in cerebrospinal fluid were dramatically influenced by modification of the f...

  13. Carbon Nanotube Growth Rate Regression using Support Vector Machines and Artificial Neural Networks

    Science.gov (United States)

    2014-03-27

    rates are realized by this faster search. 1.3 Assumptions The machine learning approach used for extracting optimal growth parameters assumes the catalyst...and high strength polymers. [25] All carbon to carbon bonds are filled in a CNT so they are chemically inert and stable in acids, bases and solvents ...research in maximizing CNT length. SWNTs of 18.5 cm in length were obtained by using an ethanol precursor and an iron molybdenum catalyst [10]. Also, by

  14. Growth rate and calcium carbonate accumulation of Halimeda macrolobaDecaisne (Chlorophyta: Halimedaceae in Thai waters

    Directory of Open Access Journals (Sweden)

    Jaruwan Mayakun

    2014-08-01

    Full Text Available Halimeda macroloba Decaisne can utilize the CO2 used for carbon fixation in photosynthesis and use bicarbonate as the main carbon source for calcification. Although Halimeda has been recognized as a carbon sink species, the calcium accumulation of Halimeda species in Thai waters remain poorly understood. In this study, the highest density of H. macroloba was 26 thalli/m2 and Halimeda quickly produced 1-2 new segments/thallus/day or 20.1 mg dry weight/thallus/day. Its calcium carbonate accumulation rate was 16.6 mg CaCO3 /thallus/day, or 82.46 % per thallus. In Thailand, however, only three scientific papers of growth rate and CaCO3 accumulation rate of H. macroloba have been found and collected. Of these records, the mean density was 26-104 thalli/m2 . The growth rate of H. macroloba was around 1-2 mg dry weight/day and the CaCO3 accumulation rate varied around 41-91%. Thus, Halimeda has a great potential to decrease the carbon dioxide concentration in the ocean.

  15. Biological mechanisms discriminating growth rate and adult body weight phenotypes in two Chinese indigenous chicken breeds.

    Science.gov (United States)

    Dou, Tengfei; Zhao, Sumei; Rong, Hua; Gu, Dahai; Li, Qihua; Huang, Ying; Xu, Zhiqiang; Chu, Xiaohui; Tao, Linli; Liu, Lixian; Ge, Changrong; Te Pas, Marinus F W; Jia, Junjing

    2017-06-20

    Intensive selection has resulted in increased growth rates and muscularity in broiler chickens, in addition to adverse effects, including delayed organ development, sudden death syndrome, and altered metabolic rates. The biological mechanisms underlying selection responses remain largely unknown. Non-artificially-selected indigenous Chinese chicken breeds display a wide variety of phenotypes, including differential growth rate, body weight, and muscularity. The Wuding chicken breed is a fast growing large chicken breed, and the Daweishan mini chicken breed is a slow growing small chicken breed. Together they form an ideal model system to study the biological mechanisms underlying broiler chicken selection responses in a natural system. The objective of this study was to study the biological mechanisms underlying differential phenotypes between the two breeds in muscle and liver tissues, and relate these to the growth rate and body development phenotypes of the two breeds. The muscle tissue in the Wuding breed showed higher expression of muscle development genes than muscle tissue in the Daweishan chicken breed. This expression was accompanied by higher expression of acute inflammatory response genes in Wuding chicken than in Daweishan chicken. The muscle tissue of the Daweishan mini chicken breed showed higher expression of genes involved in several metabolic mechanisms including endoplasmic reticulum, protein and lipid metabolism, energy metabolism, as well as specific immune traits than in the Wuding chicken. The liver tissue showed fewer differences between the two breeds. Genes displaying higher expression in the Wuding breed than in the Daweishan breed were not associated with a specific gene network or biological mechanism. Genes highly expressed in the Daweishan mini chicken breed compared to the Wuding breed were enriched for protein metabolism, ABC receptors, signal transduction, and IL6-related mechanisms. We conclude that faster growth rates and larger

  16. Subcritical crack growth and mechanical weathering: a new consideration of how moisture influences rock erosion rates.

    Science.gov (United States)

    Eppes, Martha-Cary; Keanini, Russell; Hancock, Gregory S.

    2016-04-01

    The contributions of moisture to the mechanical aspects of rock weathering and regolith production are poorly quantified. In particular, geomorphologists have largely overlooked the role of subcritical crack growth processes in physical weathering and the fact that moisture strongly influences the rates of those processes. This influence is irrespective of the function that moisture plays in stress loading mechanisms like freezing or hydration. Here we present a simple numerical model that explores the efficacy of subcritical crack growth in granite rock subaerially exposed under a range of moisture conditions. Because most weathering-related stress loading for rocks found at, or near, Earth's surface (hereafter surface rocks) is cyclic, we modeled crack growth using a novel combination of Paris' Law and Charles' Law. This combination allowed us to apply existing empirically-derived data for the stress corrosion index of Charles' Law to fatigue cracking. For stress, we focused on the relatively straightforward case of intergranular stresses that arise during solar-induced thermal cycling by conductive heat transfer, making the assumption that such stresses represent a universal minimum weathering stress experienced by all surface rocks. Because all other tensile weathering-related stresses would be additive in the context of crack growth, however, our model can be adapted to include other stress loading mechanisms. We validated our calculations using recently published thermal-stress-induced cracking rates. Our results demonstrate that 1) weathering-induced stresses as modeled herein, and as published by others, are sufficient to propagate fractures subcritically over long timescales with or without the presence of water 2) fracture propagation rates increase exponentially with respect to moisture, specifically relative humidity 3) fracture propagation rates driven by thermal cycling are strongly dependent on the magnitude of diurnal temperature ranges and the

  17. Population growth, interest rate, and housing tax in the transitional China

    Science.gov (United States)

    He, Ling-Yun; Wen, Xing-Chun

    2017-03-01

    This paper combines and develops the models in Lastrapes (2002) and Mankiw and Weil (1989), which enables us to analyze the effects of interest rate and population growth shocks on housing price in one integrated framework. Based on this model, we carry out policy simulations to examine whether the housing (stock or flow) tax reduces the housing price fluctuations caused by interest rate or population growth shocks. Simulation results imply that the choice of housing tax tools depends on the kind of shock that housing market faces. In the situation where the housing price volatility is caused by the population growth shock, the flow tax can reduce the volatility of housing price while the stock tax makes no difference to it. If the shock is resulting from the interest rate, the policy maker should not impose any kind of the housing taxes. Furthermore, the effect of one kind of the housing tax can be strengthened by that of the other type of housing tax.

  18. Validating estimates of the growth rate of structure with modified gravity simulations

    CERN Document Server

    Barreira, Alexandre; Schmidt, Fabian

    2016-01-01

    We perform a consistent end-to-end validation of estimates of the growth rate of structure, described by the parameter combination $f\\sigma_8$, in modified gravity cosmologies. We consider an analysis pipeline based on the redshift-space distortion modelling of the clustering wedges statistic of the galaxy correlation function and apply it to mock catalogues of $\\Lambda{\\rm CDM}$ and the normal branch of DGP cosmologies. We employ a halo occupation distribution approach to construct our mocks, which we ensure resemble the CMASS sample from BOSS in terms of the total galaxy number density and large scale amplitude of the power spectrum monopole. We show that the clustering wedges model successfully recovers the true growth rate difference between DGP and $\\Lambda{\\rm CDM}$, even for cases with over 40% enhancement in $f\\sigma_8$ compared to $\\Lambda{\\rm CDM}$. The unbiased performance of the clustering wedges model allows us to use the growth rate values estimated from the BOSS LOWZ and CMASS samples to constr...

  19. Influence of Production System, Sex and Litter Size on Growth Rates in Turcana Lambs

    Directory of Open Access Journals (Sweden)

    Dinu Gavojdian

    2013-10-01

    Full Text Available Lamb meat production has become the main source of income in the Romanian sheep farming industry, representing over 66% of the total returns. Turcana breed represents over 70% of the national flock, and 92% of the sheep bred in western Romania. However, meat production potential and growth rates of the breed are low, and thus strategies to improve performance of the Turcana lambs need to be identified. Aim of the current research was to evaluate the effects that sex and litter size have on the growth rates of lambs from Turcana breed under extensive and semi-intensive production systems. Weaning weight was significantly (p≤0.001 influenced by the production system, with lambs reared extensively registering a average body weights of 18.23±0.094 kg at the age of 90 days, while the semi-intensively reared lambs registered an average weight of 20.19±0.082 kg. It was concluded that all three factors taken into study significantly influence growth rates in Turcana lambs and that weight of the lamb(s at the age of 28 days should be included as a selection trait within the Turcana breed genetic improvement plan.

  20. Intrinsic fatigue crack growth rates for Al-Li-Cu-Mg alloys in vacuum

    Science.gov (United States)

    Slavik, D. C.; Blankenship, C. P., Jr.; Starke, E. A., Jr.; Gangloff, R. P.

    1993-01-01

    The influences of microstructure and deformation mode on inert environment intrinsic fatigue crack propagation were investigated for Al-Li-Cu-Mg alloys AA2090, AA8090, and X2095 compared to AA2024. The amount of coherent shearable delta-prime (Al3Li) precipitates and extent of localized planar slip deformation were reduced by composition (increased Cu/Li in X2095) and heat treatment (double aging of AA8090). Intrinsic growth rates, obtained at high constant K(max) to minimize crack closure and in vacuum to eliminate any environmental effect, were alloy dependent; da/dN varied up to tenfold based on applied Delta-K or Delta-K/E. When compared based on a crack tip cyclic strain or opening displacement parameter, growth rates were equivalent for all alloys except X2095-T8, which exhibited unique fatigue crack growth resistance. Tortuous fatigue crack profiles and large fracture surface facets were observed for each Al-Li alloy independent of the precipitates present, particularly delta-prime, and the localized slip deformation structure. Reduced fatigue crack propagation rates for X2095 in vacuum are not explained by either residual crack closure or slip reversibility arguments; the origin of apparent slip band facets in a homogeneous slip alloy is unclear.