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Sample records for modelling growth reproduction

  1. A size-structured model of bacterial growth and reproduction.

    Science.gov (United States)

    Ellermeyer, S F; Pilyugin, S S

    2012-01-01

    We consider a size-structured bacterial population model in which the rate of cell growth is both size- and time-dependent and the average per capita reproduction rate is specified as a model parameter. It is shown that the model admits classical solutions. The population-level and distribution-level behaviours of these solutions are then determined in terms of the model parameters. The distribution-level behaviour is found to be different from that found in similar models of bacterial population dynamics. Rather than convergence to a stable size distribution, we find that size distributions repeat in cycles. This phenomenon is observed in similar models only under special assumptions on the functional form of the size-dependent growth rate factor. Our main results are illustrated with examples, and we also provide an introductory study of the bacterial growth in a chemostat within the framework of our model.

  2. Caenorhabditis elegans as a Model for Toxic Effects of Nanoparticles: Lethality, Growth, and Reproduction.

    Science.gov (United States)

    Maurer, Laura L; Ryde, Ian T; Yang, Xinyu; Meyer, Joel N

    2015-11-02

    The nematode Caenorhabditis elegans is extensively utilized in toxicity studies. C. elegans offers a high degree of homology with higher organisms, and its ease of use and relatively inexpensive maintenance have made it an attractive complement to mammalian and ecotoxicological models. C. elegans provides multiple benefits, including the opportunity to perform relatively high-throughput assays on whole organisms, a wide range of genetic tools permitting investigation of mechanisms and genetic sensitivity, and transparent bodies that facilitate toxicokinetic studies. This unit describes protocols for three nanotoxicity assays in C. elegans: lethality, growth, and reproduction. This unit focuses on how to use these well-established assays with nanoparticles, which are being produced in ever-increasing volume and exhibit physicochemical properties that require alteration of standard toxicity assays. These assays permit a broad phenotypic assessment of nanotoxicity in C. elegans, and, when used in combination with genetic tools and other assays, also permit mechanistic insight. Copyright © 2015 John Wiley & Sons, Inc.

  3. A dynamic-bioenergetics model to assess depth selection and reproductive growth by lake trout (Salvelinus namaycush).

    Science.gov (United States)

    Plumb, John M; Blanchfield, Paul J; Abrahams, Mark V

    2014-06-01

    We coupled dynamic optimization and bioenergetics models to assess the assumption that lake trout (Salvelinus namaycush) depth distribution is structured by temperature, food availability, and predation risk to maximize reproductive mass by autumn spawning. Because the model uses empirical daily thermal-depth profiles recorded in a small boreal shield lake (lake 373 at the Experimental Lakes Area, northwestern Ontario) during 2 years of contrasting thermal stratification patterns, we also assessed how climate-mediated changes in lakes may affect the vertical distribution, growth, and fitness of lake trout, a cold-water top predator. The depths of acoustic-tagged lake trout were recorded concurrently with thermal-depth profiles and were compared to model output, enabling an assessment of model performance in relation to the observed fish behavior and contrasting thermal conditions. The depths and temperatures occupied by simulated fish most closely resembled those of the tagged fish when risk of predation was included in the model, indicating the model may incorporate the most important underlying mechanisms that determine lake trout depth. Annual differences suggest less use of shallow (warm), productive habitats, resulting in markedly less reproductive mass, during the year with the warm stratification pattern. Mass for reproduction may be lower in warmer conditions because of reduced reproductive investment, yet survival may be inadvertently higher because risky surface waters may be avoided more often in warmer, shallower, and metabolically costly conditions. At a minimum our study suggests that lake trout reproductive mass and fitness may be expected to change under the anticipated longer and warmer stratification patterns.

  4. Growth and reproductive attributes of radionuclide phytoremediators ...

    African Journals Online (AJOL)

    The study reveals that growth attributes including relative growth rate, net assimilation rate, leaf are index and specific leaf area, dry matter allocated to stem and leaves and number of reproductive organs decreased with the increase of radionuclide content of the plant, while the dry matter allocated to root and reproductive ...

  5. Age-growth models for tilapia Oreochromis aureus (Perciformes, Cichlidae of the Infiernillo reservoir, Mexico and reproductive behaviour

    Directory of Open Access Journals (Sweden)

    Lourdes Jiménez-Badillo

    2006-06-01

    Full Text Available In presence of a decrease in the catch from Infiernillo reservoir, Michoacán-Guerrero, México, age and growth of tilapia Oreochromis aureus (Steindachner 1864 were estimated, as indispensable attributes for fishery management. Evaluations included scales and opercular bones readings and length frequency analysis. The population structure was determined too. Due to the great variation of tilapia individual growth and with the objective to have reliable growth estimations, linearized, non-parametric and non-linear methods were used and their applicability discussed. Comparison of ages determined from these methods revealed that opercular bones readings had advantages over scales. Reproduction and competition for space and food were considered as responsible factors for ring-formation on tilapia hard structures. The non-linear method was considered the best for modelling populations highly variable, which is characteristic of tilapia and tropical fish with multiple spawns. The growth parameters estimated were L∞ = 479 mm, K = 0.46/yr, t o = -0.055 yr. The tilapia population in Infiernillo reservoir is dominated by juveniles less than 1.5 years old. The fishery activity is affecting the tilapia population growth because are caught when they have not yet spawned. Therefore, this fishery is in urgent need of regulation. Increasing the mesh size of the gill nets might contribute to protect the reproductive potential of the stock. Rev. Biol. Trop. 54(2: 577-588. Epub 2006 Jun 01.Ante el continuo decremento en las capturas de tilapia de la presa Infiernillo, Michoacán- Guerrero, México, se estimó la edad y crecimiento de Oreochromis aureus (Steindachner 1864 que son atributos indispensables que deben conocerse para realizar el manejo de la pesquería. La evaluación incluyó la lectura de marcas de crecimiento en escamas y opérculos, y el análisis de frecuencia de tallas. También se estimó la estructura de edad de la población. Debido a la

  6. Growth and reproductive effects from dietary exposure to Aroclor 1268 in mink (Neovison vison), a surrogate model for marine mammals.

    Science.gov (United States)

    Folland, William R; Newsted, John L; Fitzgerald, Scott D; Fuchsman, Phyllis C; Bradley, Patrick W; Kern, John; Kannan, Kurunthachalam; Remington, Richard E; Zwiernik, Matthew J

    2016-03-01

    Polychlorinated biphenyls (PCBs) from the commercial mixture Aroclor 1268 were historically released into the Turtle-Brunswick River estuary (southeastern Georgia, USA) from industrial operations. Sum PCBs (ΣPCBs) in blubber samples from Turtle-Brunswick River estuary bottlenose dolphins (Tursiops truncatus) have been reported at concentrations more than 10-fold higher than those observed in dolphins from adjacent regional estuaries. Given that toxicity data specific to Aroclor 1268 and applicable to marine mammals are limited, predicting the toxic effects of Aroclor 1268 in dolphins is uncertain, particularly because of its unique congener profile and associated physiochemical characteristics compared with other PCB mixtures. American mink (Neovison vison) were chosen as a surrogate model for cetaceans to develop marine mammalian PCB toxicity benchmarks. Mink are a suitable surrogate species for cetaceans in toxicity studies because of similarities in diet and taxonomic class, and a characteristic sensitivity to PCBs provides a potential safety factor when using mink toxicology data for cross-species extrapolations. Effects of dietary exposure to Aroclor 1268 on reproduction, growth, and mortality in mink were compared with both a negative control and a positive control (3,3',4,4',5-pentachlorobiphenyl, PCB 126). Aroclor 1268 dietary ΣPCB concentrations ranged from 1.8 µg/g feed wet weight to 29 µg/g feed wet weight. Whelp success was unaffected by Aroclor 1268 exposure at any level. Treatment mean litter size, kit growth, and kit survival were adversely affected relative to the negative control at dietary ΣPCB concentrations of 10.6 µg/g feed wet weight and greater. © 2015 SETAC.

  7. Estrogen and Growth Hormone and their Roles in Reproductive Function

    OpenAIRE

    Hüseyin Baki ÇİFTCİ

    2013-01-01

    The aim of this study was to review the effect of estrogen on growth hormone secretion and the roles of estrogen and growth hormone in reproductive function. Estrogen is the main hormone affecting growth, development, maturation and functioning of reproductive tract as well as the sexual differentiation and the behavior. Growth hormone is also important factor in sexual maturation and attainment of puberty. The impact of estrogen on growth hormone secretion has been reported in rodents and pr...

  8. Growth Hormone Overexpression Disrupts Reproductive Status Through Actions on Leptin

    Directory of Open Access Journals (Sweden)

    Ji Chen

    2018-03-01

    Full Text Available Growth and reproduction are closely related. Growth hormone (GH-transgenic common carp exhibit accelerated growth and delayed reproductive development, which provides an amenable model to study hormone cross talk between the growth and reproductive axes. We analyzed the energy status and reproductive development in GH-transgenic common carp by using multi-tissue RNA sequencing, real-time-PCR, Western blotting, ELISA, immunofluorescence, and in vitro incubation. The expression of gys (glycogen synthase and igfbp1 (insulin-like growth factor binding protein as well as blood glucose concentrations are lower in GH-transgenic carp. Agrp1 (agouti-related protein 1 and sla (somatolactin a, which are related to appetite and lipid catabolism, are significantly higher in GH-transgenic carp. Low glucose content and increased appetite indicate disrupted metabolic and energy deprivation status in GH-transgenic carp. Meanwhile, the expression of genes, such as gnrhr2 (gonadotropin-releasing hormone receptor 2, gthα (gonadotropin hormone, alpha polypeptide, fshβ (follicle stimulating hormone, beta polypeptide, lhβ [luteinizing hormone, beta polypeptide] in the pituitary, cyp19a1a (aromatase A in the gonad, and cyp19a1b (aromatase B in the hypothalamus, are decreased in GH-transgenic carp. In contrast, pituitary gnih (gonadotropin inhibitory hormone, drd1 (dopamine receptor D1, drd3 (dopamine receptor D3, and drd4 (dopamine receptor D4 exhibit increased expression, which were associated with the retarded reproductive development. Leptin receptor mRNA was detected by fluorescence in situ hybridization in the pituitary including the pars intermedia and proximal pars distalis, suggesting a direct effect of leptin on LH. Recombinant carp Leptin protein was shown to stimulate pituitary gthα, fshβ, lhβ expression, and ovarian germinal vesicle breakdown in vitro. In addition to neuroendocrine factors, we suggest that reduced hepatic leptin signaling to the

  9. CAROTENOID CLEAVAGE DIOXYGENASE 7 modulates plant growth, reproduction, senescence, and determinate nodulation in the model legume Lotus japonicas

    NARCIS (Netherlands)

    Liu, J.; Novero, M.; Charnikhova, T.; Ferrandino, A.; Schubert, A.; Ruyter-Spira, C.P.; Biofante, P.; Lovisolo, C.; Bouwmeester, H.J.

    2013-01-01

    Strigolactones (SLs) are newly identified hormones that regulate multiple aspects of plant development, infection by parasitic weeds, and mutualistic symbiosis in the roots. In this study, the role of SLs was studied for the first time in the model plant Lotus japonicus using transgenic lines

  10. Trends in clinical reproductive medicine research: 10 years of growth.

    Science.gov (United States)

    Aleixandre-Benavent, Rafael; Simon, Carlos; Fauser, Bart C J M

    2015-07-01

    To study the most important metrics of publication in the field of reproductive medicine over the decade 2003-2012 to aid in discerning the clinical, social, and epidemiologic implications of this relatively new but rapidly emerging area in medical sciences. Bibliometric analysis of most-cited publications from Web of Science databases. Not applicable. None. None. Most productive and frequently cited investigators, institutions, and countries and specific areas of research, scientific collaborations, and comparison of the growth of reproductive medicine research compared with other areas of medical investigation such as obstetrics and gynecology and related science categories. We found that 90 investigators with more than 1,000 citations had jointly published 4,010 articles. A continued rise in the impact factor of reproductive medicine journals was seen. The number of publications in reproductive medicine grew more rapidly compared with other science categories. Presently 22% of highly cited articles in reproductive medicine research are published in journals belonging to science categories outside reproductive medicine. The most-cited study groups are situated in the Netherlands, Belgium, Spain, the United States, and the United Kingdom, and collaborative studies have been increasing. Reproductive medicine research and subsequent clinical development have attained scientific growth and maturity. High-quality research is increasingly being published in high-impact journals. The increase in (inter)national collaborations seems to be key to the field's success. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  11. Characterizing the reproduction number of epidemics with early subexponential growth dynamics

    DEFF Research Database (Denmark)

    Chowell, Gerardo; Viboud, Cécile; Simonsen, Lone

    2016-01-01

    mechanisms. Here, we introduce the generalized growth model to characterize the early growth profile of outbreaks and estimate the effective reproduction number, with no need for explicit assumptions about the shape of epidemic growth. We demonstrate this phenomenological approach using analytical results...... datasets (pandemic influenza, measles, smallpox, bubonic plague, cholera, foot-and-mouth disease, HIV/AIDS and Ebola) with model estimates supporting subexponential growth dynamics. The rapid decline in effective reproduction number predicted by analytical results and observed in real and synthetic......Early estimates of the transmission potential of emerging and re-emerging infections are increasingly used to inform public health authorities on the level of risk posed by outbreaks. Existing methods to estimate the reproduction number generally assume exponential growth in case incidence...

  12. Age-specific growth, reproductive values, and intrinsic r

    Directory of Open Access Journals (Sweden)

    Robert Schoen

    2011-06-01

    Full Text Available The age-specific growth function of an observed population and the reproductive value function based on the population's current vital rates determine the intrinsic rate of growth implied by those vital rates through the simple relationship given in equation (1. That equation establishes the analytical significance of age-specific growth, and leads to relationships that quantify a population's approach to stability and that specify the extraordinarily close connection between reproductive values and population momentum.

  13. Is growth rate more important than survival and reproduction in ...

    African Journals Online (AJOL)

    The local Djallonké sheep in Ghana is characterized by slow growth and low reproductive rates, but is resistant to most diseases and parasites (survival traits). In an attempt to improve the performance of the local sheep, the Ministry of Food and Agriculture has chosen growth rate as the breeding objective. This is being ...

  14. Age, growth and reproductive biology of the blue shark Prionace ...

    African Journals Online (AJOL)

    The age, growth and reproductive biology of the blue shark Prionace glauca from South African waters were assessed using 205 specimens, ranging in total length (TL) from 72 to 313 cm. Greater number of males (120) than females (85) were examined as they were more frequently caught. Age and growth parameters ...

  15. Are reproductive skew models evolutionarily stable?

    OpenAIRE

    Kokko, Hanna

    2003-01-01

    Reproductive skew theory has become a popular way to phrase problems and test hypotheses of social evolution. The diversity of reproductive skew models probably stems from the ease of generating new variations. However, I show that the logical basis of skew models, that is, the way in which group formation is modelled, makes use of hidden assumptions that may be problematical as they are unlikely to be fulfilled in all social systems. I illustrate these problems by re-analysing the basic conc...

  16. Growth and reproductive attributes of radionuclide phytoremediators ...

    African Journals Online (AJOL)

    use

    2011-11-23

    Nov 23, 2011 ... Key words: Uranium, thorium, plant growth, resource allocation. INTRODUCTION .... species are summarized in Table 1. The radionuclide content of the soil in the study sites is varied. Uranium and thorium concentrations attained the lowest values of ...... content will establish the correlation between metal.

  17. The effects of food availability on growth and reproduction of Daphnia magna exposed to silver nanoparticles

    DEFF Research Database (Denmark)

    Mackevica, Aiga; Skjolding, Lars Michael; Gergs, A.

    offspring, and number of neonates produced. The data obtained from the chronic tests are intended for modeling using the Dynamic Energy Budget (DEB) theory, which will hopefully provide information on growth and reproduction strategy of the test animals. The concentrations of silver in the test medium over......The number of available studies on the acute effects of silver nanoparticles (AgNP) on aquatic organisms has increased dramatically in recent years, but there is still very limited information available on chronic effects. In this study, a series of Daphnia magna 21-days reproduction test (OECD 211...... exposed to 10 μgAg/L showed enhanced reproduction compared to controls, however the toxic effects on growth and reproduction appeared in concentrations above 20 μgAg/L. A reference test was performed with silver nitrate in concentrations ranging from 0.25 to 1.5 μgAg/L. Mortality was increasing...

  18. Assessment of the reproductive and growth performance of two ...

    African Journals Online (AJOL)

    Genes were introduced from the prolific Finnish Landrace sheep breed by crossbreeding with indigenous breeds to produce several composites. In this study, two of these composites were compared to the Dorper in terms of reproductive characteristics and growth. Mean ovulation rate of Composites 1 and 2 was 1.93 and ...

  19. Early Growth and Reproductive Performances of Horro Cattle and ...

    African Journals Online (AJOL)

    A cross-sectional survey, an assessment of recorded data and measurements of different traits were conducted to determine the reproductive and early growth performances of Horro cattle and their F1 Jersey crosses of the study area. The mean(SD) total farmland, cropland and grazing land holdings of individual ...

  20. Growth and reproductive performance of captive grass cutter ...

    African Journals Online (AJOL)

    135.0 g) and was significantly different (p<0.05) from other treatments. These suggest that M. oleifera leaf could be a potential and promising dietary supplementation that would affect growth, and reproductive performance of T. swinderianus in ...

  1. Growth and reproduction of two molluscs from an exposed sandy ...

    African Journals Online (AJOL)

    Populations of a gastropod, Bullia rhodostoma, and a bivalve,. Donax sordidus, were monitored quantitatively over one year on an exposed sandy beach which supports a rich macrofauna. B. rhodostoma had a single reproductive season with copulation in early summer. Growth was slow and is described by a Von ...

  2. Growth and reproduction of two molluscs from an exposed sandy ...

    African Journals Online (AJOL)

    Populations of a gastropod, Bullia rhodostoma, and a bivalve, Donax sordidus, were monitored quantitatively over one year on an exposed sandy beach which supports a rich macrofauna. B. rhodostoma had a single reproductive season with copulation in early summer. Growth was slow and is described by a Von ...

  3. Growth and Reproductive Outcomes in Congenital Adrenal Hyperplasia

    Directory of Open Access Journals (Sweden)

    Todd D. Nebesio

    2010-01-01

    Full Text Available The treatment of congenital adrenal hyperplasia (CAH due to 21-hydroxylase deficiency is complex. In addition to disease control, important therapeutic goals are the maintenance of normal growth and the acquisition of normal reproductive function. Here, data regarding final adult height (FH in patients with CAH will be reviewed. Additional difficulties associated with CAH, including risks of obesity and hypertension, will be discussed. Information about fertility and reproductive outcomes in men and women with CAH will also be summarized. Although the treatment of each child with CAH needs to be individualized, close medical followup and laboratory monitoring along with good compliance can often result in positive clinical outcomes.

  4. Characterizing the reproduction number of epidemics with early subexponential growth dynamics.

    Science.gov (United States)

    Chowell, Gerardo; Viboud, Cécile; Simonsen, Lone; Moghadas, Seyed M

    2016-10-01

    Early estimates of the transmission potential of emerging and re-emerging infections are increasingly used to inform public health authorities on the level of risk posed by outbreaks. Existing methods to estimate the reproduction number generally assume exponential growth in case incidence in the first few disease generations, before susceptible depletion sets in. In reality, outbreaks can display subexponential (i.e. polynomial) growth in the first few disease generations, owing to clustering in contact patterns, spatial effects, inhomogeneous mixing, reactive behaviour changes or other mechanisms. Here, we introduce the generalized growth model to characterize the early growth profile of outbreaks and estimate the effective reproduction number, with no need for explicit assumptions about the shape of epidemic growth. We demonstrate this phenomenological approach using analytical results and simulations from mechanistic models, and provide validation against a range of empirical disease datasets. Our results suggest that subexponential growth in the early phase of an epidemic is the rule rather the exception. Mechanistic simulations show that slight modifications to the classical susceptible-infectious-removed model result in subexponential growth, and in turn a rapid decline in the reproduction number within three to five disease generations. For empirical outbreaks, the generalized-growth model consistently outperforms the exponential model for a variety of directly and indirectly transmitted diseases datasets (pandemic influenza, measles, smallpox, bubonic plague, cholera, foot-and-mouth disease, HIV/AIDS and Ebola) with model estimates supporting subexponential growth dynamics. The rapid decline in effective reproduction number predicted by analytical results and observed in real and synthetic datasets within three to five disease generations contrasts with the expectation of invariant reproduction number in epidemics obeying exponential growth. The

  5. Characterizing the reproduction number of epidemics with early subexponential growth dynamics

    Science.gov (United States)

    Viboud, Cécile; Simonsen, Lone; Moghadas, Seyed M.

    2016-01-01

    Early estimates of the transmission potential of emerging and re-emerging infections are increasingly used to inform public health authorities on the level of risk posed by outbreaks. Existing methods to estimate the reproduction number generally assume exponential growth in case incidence in the first few disease generations, before susceptible depletion sets in. In reality, outbreaks can display subexponential (i.e. polynomial) growth in the first few disease generations, owing to clustering in contact patterns, spatial effects, inhomogeneous mixing, reactive behaviour changes or other mechanisms. Here, we introduce the generalized growth model to characterize the early growth profile of outbreaks and estimate the effective reproduction number, with no need for explicit assumptions about the shape of epidemic growth. We demonstrate this phenomenological approach using analytical results and simulations from mechanistic models, and provide validation against a range of empirical disease datasets. Our results suggest that subexponential growth in the early phase of an epidemic is the rule rather the exception. Mechanistic simulations show that slight modifications to the classical susceptible–infectious–removed model result in subexponential growth, and in turn a rapid decline in the reproduction number within three to five disease generations. For empirical outbreaks, the generalized-growth model consistently outperforms the exponential model for a variety of directly and indirectly transmitted diseases datasets (pandemic influenza, measles, smallpox, bubonic plague, cholera, foot-and-mouth disease, HIV/AIDS and Ebola) with model estimates supporting subexponential growth dynamics. The rapid decline in effective reproduction number predicted by analytical results and observed in real and synthetic datasets within three to five disease generations contrasts with the expectation of invariant reproduction number in epidemics obeying exponential growth. The

  6. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana

    OpenAIRE

    Park, Yong-Soon; Park, Kyungseok; Kloepper, Joseph W.; Ryu, Choong-Min

    2015-01-01

    Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth...

  7. Vitellogenin RNAi halts ovarian growth and diverts reproductive proteins and lipids in young grasshoppers.

    Science.gov (United States)

    Tokar, Derek R; Veleta, Katherine A; Canzano, Joseph; Hahn, Daniel A; Hatle, John D

    2014-11-01

    Reduced reproduction extends lifespan of females in many animals. To test the effects of reproduction on storage of macronutrients, we block reproductive output in the lubber grasshopper by injecting RNAi against the precursor to egg-yolk protein, vitellogenin, in early adulthood. Controls were injected with either buffer or RNAi against the major storage protein in the hemolymph, hexamerin-90. Vitellogenin RNAi greatly reduced both levels of mRNA for vitellogenin and ovarian growth, in comparison to both controls. Fat body mass was increased upon vitellogenin RNAi, but concentrations of the three hexameric storage proteins from the hemolymph were not. Surprisingly, hemolymph vitellogenin levels were increased upon vitellogenin RNAi. Total reproductive protein (hemolymph vitellogenin plus ovarian vitellin) was unchanged by vitellogenin RNAi, as reproductive protein was diverted to the hemolymph. Similarly, the increased lipid storage upon vitellogenin RNAi was largely attributable to the reduction in lipid in the ovary, due to decreased ovarian growth. A BLAST search revealed that the 515 bp sequence of vitellogenin used for RNAi had three 11 bp regions identical to the vitellogenin receptor of the cockroach Leucophaea maderae. This suggests that our treatment, in addition to reducing levels of vitellogenin transcript, may have also blocked transport of vitellogenin from the hemolymph to the ovary. This would be consistent with halted ovarian growth simultaneous with high levels of vitellogenin in the hemolymph. Nonetheless, the accumulation of vitellogenin, instead of hexameric storage proteins, is inconsistent with a simple model of the trade-off between reproduction and storage. This was observed in young females; future studies will address whether investment of proteins may shift to the soma as individuals age. Overall, our results suggest that blockage of reproduction in young grasshoppers redirects lipids to storage and reproductive proteins to the hemolymph

  8. Urban tree growth modeling

    Science.gov (United States)

    E. Gregory McPherson; Paula J. Peper

    2012-01-01

    This paper describes three long-term tree growth studies conducted to evaluate tree performance because repeated measurements of the same trees produce critical data for growth model calibration and validation. Several empirical and process-based approaches to modeling tree growth are reviewed. Modeling is more advanced in the fields of forestry and...

  9. Are reproductive skew models evolutionarily stable?

    Science.gov (United States)

    Kokko, Hanna

    2003-02-07

    Reproductive skew theory has become a popular way to phrase problems and test hypotheses of social evolution. The diversity of reproductive skew models probably stems from the ease of generating new variations. However, I show that the logical basis of skew models, that is, the way in which group formation is modelled, makes use of hidden assumptions that may be problematical as they are unlikely to be fulfilled in all social systems. I illustrate these problems by re-analysing the basic concessive skew model with staying incentives. First, the model assumes that dispersal is an all-or-nothing response: all subordinates disperse as soon as concessions drop below a certain value. This leads to a discontinuous 'cliff-edge' shape of dominant fitness, and it is not clear that selection will balance a population at such an edge. Second, it is assumed that subordinates have perfect knowledge of their benefits if they stay in the group. I examine the effects of relaxing these two assumptions. Relaxing the first one strengthens reproductive skew theory, but relaxing the latter makes evolutionary stability disappear. In cases where subordinates cannot accurately measure benefits provided by the individual dominant with which they live, so that their behaviour instead evolves as a response to population-wide average benefits, the logic of reproductive skew models does not apply. This warns against too indiscriminate an application of reproductive skew theory to problems in social evolution: for example, transactional models of extra-pair paternity assume perfect knowledge of paternity, which is unlikely to hold true in nature. It is recommended that models specify the mechanisms by which individuals can adjust their behaviour to that of others, and pay attention to changes that occur in evolutionary versus behavioural time.

  10. On the Reproduction Number of a Gut Microbiota Model.

    Science.gov (United States)

    Barril, Carles; Calsina, Àngel; Ripoll, Jordi

    2017-11-01

    A spatially structured linear model of the growth of intestinal bacteria is analysed from two generational viewpoints. Firstly, the basic reproduction number associated with the bacterial population, i.e. the expected number of daughter cells per bacterium, is given explicitly in terms of biological parameters. Secondly, an alternative quantity is introduced based on the number of bacteria produced within the intestine by one bacterium originally in the external media. The latter depends on the parameters in a simpler way and provides more biological insight than the standard reproduction number, allowing the design of experimental procedures. Both quantities coincide and are equal to one at the extinction threshold, below which the bacterial population becomes extinct. Optimal values of both reproduction numbers are derived assuming parameter trade-offs.

  11. Reproduction numbers of infectious disease models

    Directory of Open Access Journals (Sweden)

    Pauline van den Driessche

    2017-08-01

    Full Text Available This primer article focuses on the basic reproduction number, ℛ0, for infectious diseases, and other reproduction numbers related to ℛ0 that are useful in guiding control strategies. Beginning with a simple population model, the concept is developed for a threshold value of ℛ0 determining whether or not the disease dies out. The next generation matrix method of calculating ℛ0 in a compartmental model is described and illustrated. To address control strategies, type and target reproduction numbers are defined, as well as sensitivity and elasticity indices. These theoretical ideas are then applied to models that are formulated for West Nile virus in birds (a vector-borne disease, cholera in humans (a disease with two transmission pathways, anthrax in animals (a disease that can be spread by dead carcasses and spores, and Zika in humans (spread by mosquitoes and sexual contacts. Some parameter values from literature data are used to illustrate the results. Finally, references for other ways to calculate ℛ0 are given. These are useful for more complicated models that, for example, take account of variations in environmental fluctuation or stochasticity. Keywords: Basic reproduction number, Disease control, West Nile virus, Cholera, Anthrax, Zika virus

  12. Assisted Reproduction Causes Reduced Fetal Growth Associated with Downregulation of Paternally Expressed Imprinted Genes That Enhance Fetal Growth in Mice.

    Science.gov (United States)

    Li, Bo; Chen, Shuqiang; Tang, Na; Xiao, Xifeng; Huang, Jianlei; Jiang, Feng; Huang, Xiuying; Sun, Fangzhen; Wang, Xiaohong

    2016-02-01

    Alteration of intrauterine growth trajectory is linked to metabolic diseases in adulthood. In mammalian and, specifically, human species, pregnancies through assisted reproductive technology (ART) are associated with changes in intrauterine growth trajectory. However, it is still unclear how ART alters intrauterine growth trajectory, especially reduced fetal growth in early to midgestation. In this study, using a mouse model, it was found that ART procedures reduce fetal and placental growth at Embryonic Day 10.5. Furthermore, ART leads to decreased methylation levels at H19, KvDMR1, and Snrpn imprinting control regions in the placentae, instead of fetuses. Furthermore, in the placenta, ART downregulated a majority of parentally expressed imprinted genes, which enhance fetal growth, whereas it upregulated a majority of maternally expressed genes which repress fetal growth. Additionally, the expression of genes that regulate placental development was also affected by ART. ART also downregulated a majority of placental nutrient transporters. Disruption of genomic imprinting and abnormal expression of developmentally and functionally relevant genes in placenta may influence the placental development and function, which affect fetal growth and reprogramming. © 2016 by the Society for the Study of Reproduction, Inc.

  13. Deciphering the Costs of Reproduction in Mango – Vegetative Growth Matters

    Science.gov (United States)

    Capelli, Mathilde; Lauri, Pierre-Éric; Normand, Frédéric

    2016-01-01

    Irregular fruit production across successive years is a major issue that limits the profitability of most temperate and tropical fruit crops. It is particularly affected by the reciprocal relationships between vegetative and reproductive growth. The concept of the costs of reproduction is defined in terms of losses in the potential future reproductive success caused by current investment in reproduction. This concept, developed in ecology and evolutionary biology, could provide a methodological framework to analyze irregular bearing in fruit crops, especially in relation to the spatial scale at which studies are done. The objective of this study was to investigate the direct effects of reproduction during a growing cycle on reproduction during the following growing cycle and the indirect effects through vegetative growth between these two reproductive events, for four mango cultivars and during two growing cycles. Two spatial scales were considered: the growth unit (GU) and the scaffold branch. Costs of reproduction were detected between two successive reproductive events and between reproduction and vegetative growth. These costs were scale-dependent, generally detected at the GU scale and infrequently at the scaffold branch scale, suggesting partial branch autonomy with respect to processes underlying the effects of reproduction on vegetative growth. In contrast, the relationships between vegetative growth and reproduction were positive at the GU scale and at the scaffold branch scale in most cases, suggesting branch autonomy for the processes, mainly local, underlying flowering and fruiting. The negative effect of reproduction on vegetative growth prevailed over the positive effect of vegetative growth on the subsequent reproduction. The costs of reproduction were also cultivar-dependent. Those revealed at the GU scale were related to the bearing behavior of each cultivar. Our results put forward the crucial role of vegetative growth occurring between two

  14. Interannual variability of growth and reproduction in Bursera simaruba: the role of allometry and resource variability.

    Science.gov (United States)

    Hulshof, Catherine M; Stegen, James C; Swenson, Nathan G; Enquist, Carolyn A F; Enquist, Brian J

    2012-01-01

    Plants are expected to differentially allocate resources to reproduction, growth, and survival in order to maximize overall fitness. Life history theory predicts that the allocation of resources to reproduction should occur at the expense of vegetative growth. Although it is known that both organism size and resource availability can influence life history traits, few studies have addressed how size dependencies of growth and reproduction and variation in resource supply jointly affect the coupling between growth and reproduction. In order to understand the relationship between growth and reproduction in the context of resource variability, we utilize a long-term observational data set consisting of 670 individual trees over a 10-year period within a local population of Bursera simaruba (L.) Sarg. We (1) quantify the functional form and variability in the growth-reproduction relationship at the population and individual-tree level and (2) develop a theoretical framework to understand the allometric dependence of growth and reproduction. Our findings suggest that the differential responses of allometric growth and reproduction to resource availability, both between years and between microsites, underlie the apparent relationship between growth and reproduction. Finally, we offer an alternative approach for quantifying the relationship between growth and reproduction that accounts for variation in allometries.

  15. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana

    Directory of Open Access Journals (Sweden)

    Yong-Soon Park

    2015-09-01

    Full Text Available Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation.

  16. Plant Growth-Promoting Rhizobacteria Stimulate Vegetative Growth and Asexual Reproduction of Kalanchoe daigremontiana.

    Science.gov (United States)

    Park, Yong-Soon; Park, Kyungseok; Kloepper, Joseph W; Ryu, Choong-Min

    2015-09-01

    Certain bacterial species associate with plant roots in soil. The plant growth-promoting rhizobacteria (PGPR) stimulate plant growth and yield in greenhouse and field. Here, we examined whether application of known bacilli PGPR strains stimulated growth and asexual reproduction in the succulent plant Kalanchoe daigremontiana. Four PGPR strains B. amyloliquefaciens IN937a, B. cereus BS107, B. pumilus INR7, and B. subtilis GB03 were applied to young plantlets by soil-drenching, and plant growth and development was monitored for three months. Aerial growth was significantly stimulated in PGPR-inoculated plants, which was observed as increases in plant height, shoot weight, and stem width. The stimulated growth influenced plant development by increasing the total number of leaves per plant. Treatment with bacilli also increased the total root biomass compared with that of control plants, and led to a 2-fold increase in asexual reproduction and plantlet formation on the leaf. Collectively, our results firstly demonstrate that Bacillus spp. promote vegetative development of K. daigremontiana, and the enhanced growth stimulates asexual reproduction and plantlet formation.

  17. Life history and the competitive environment: trajectories of growth, maturation, and reproductive output among chacma baboons.

    Science.gov (United States)

    Johnson, Sara E

    2003-01-01

    The social environment is a key feature influencing primate life histories. Chacma baboons (Papio hamadryas ursinus) are a female-bonded species with a strict linear dominance hierarchy. In this species, the allocation of energy to competing demands of growth and reproduction is hypothesized to vary as a function of competitive ability, which in turn increases with social rank. Since growth rate is a major component of life history models, measures of age-specific growth were used to analyze variation in life history traits across social ranks. Weights of 42 immature baboons were obtained without sedation or baiting from a troop of well-habituated chacma baboons in the Okavango Delta, Botswana. Using demographic and weight data from this wild population, five main findings emerged: 1) Weight for age and growth rate of infant and juvenile females are positively associated with maternal rank. 2) Male growth is not influenced by maternal rank. 3) Female growth shows smaller variation across feeding conditions than male growth. 4) Low-ranking adult females continue investment in offspring through prolonged lactation until they reach a weight comparable to that of high-ranking infants. 5) The benefit of rank to reproductive success shown in this study is 0.83 additional offspring. Reproductive span determined predominantly by age at maturation contributes 27-38% to the difference in expected number of offspring by rank, vs. 62-73% due to reproductive rate. These findings have major implications for understanding the role of social environment in phenotypic plasticity of life history traits, and in the evolution of primate life histories. Copyright 2003 Wiley-Liss, Inc.

  18. Individual heterogeneity and offspring sex affect the growth-reproduction trade-off in a mammal with indeterminate growth.

    Science.gov (United States)

    Gélin, Uriel; Wilson, Michelle E; Cripps, Jemma; Coulson, Graeme; Festa-Bianchet, Marco

    2016-04-01

    Reproduction can lead to a trade-off with growth, particularly when individuals reproduce before completing body growth. Kangaroos have indeterminate growth and may always face this trade-off. We combined an experimental manipulation of reproductive effort and multi-year monitoring of a large sample size of marked individuals in two populations of eastern grey kangaroos to test the predictions (1) that reproduction decreases skeletal growth and mass gain and (2) that mass loss leads to reproductive failure. We also tested if sex-allocation strategies influenced these trade-offs. Experimental reproductive suppression revealed negative effects of reproduction on mass gain and leg growth from 1 year to the next. Unmanipulated females, however, showed a positive correlation between number of days lactating and leg growth over periods of 2 years and longer, suggesting that over the long term, reproductive costs were masked by individual heterogeneity in resource acquisition. Mass gain was necessary for reproductive success the subsequent year. Although mothers of daughters generally lost more mass than females nursing sons, mothers in poor condition experienced greater mass gain and arm growth if they had daughters than if they had sons. The strong links between individual mass changes and reproduction suggest that reproductive tactics are strongly resource-dependent.

  19. Drought effects on reproductive and growth characteristics in seed orchards

    International Nuclear Information System (INIS)

    Varol, T.; Ozel, H. B.; Bilir, N.

    2017-01-01

    Global climate change is one of the most important environmental problems, and it is also known that this change will lead to negative effects such as drought and increase in global temperature. This change is also estimated to increase its episodic effects negatively on growth and reproduction of the forest trees. In order to estimate the episodic or continuous effects of the drought, it is necessary to carry out studies based on long-term data. One of these studies are the investigation to be carried out on seed orchards that are one of the most important seed resources in forestry. Within this context, in this study, we determined to the reproductive and growth responses of the clones to the drought that continued in the most drought season (2012) for 2 subsequent years along with 65-year climate data for Red Pine (Pinus brutia Ten.) and Taurus Cedar (Cedrus libani Rich.). The relationships of SPEI values with seed characteristics and cone production were examined by using Spearman Correlation Analysis. According to the results obtained from this study, it was found that the severe drought was effected the reproductive characteristics of both of red pine and cedar. The effect of drought on the number of cone (r=-0.810, P=0.022) in red pine and on the number of 1-year-old cones (r=-0.40, P=0.027) and on cone moisture (r=-0.715, P=0.022) in cedar was quite evident. These results indicate that approximately 65% of the change in number of cone in Red Pine and approximately 51% of the change in moisture content of the cones in cedar can be explained with the drought. From the data, it is clear that the drought is effective on the cone yield and seed characteristics in seed orchards of both of Red Pine and Taurus Cedar species. (author)

  20. Growth and Reproduction of Artificially Fed Cnaphalocrocis medinalis

    Directory of Open Access Journals (Sweden)

    Jian XU

    2012-09-01

    Full Text Available The growth and reproduction of rice leaffolder, Cnaphalocrocis medinalis, fed on an artificial diet were studied. The results showed that the larvae were able to grow and pupate on the artificial diet. The durations of larvae and pupas of C. medinalis on the artificial diet were 28.1 d and 10.1 d, postponed 4.9 d and 1.7 d respectively, compared with those reared with rice leaves. The number of ovipositions was 41.6 per female, 26.2% higher than that fed on rice leaves. Survival rate curve of larvae was a descent function of mortality-age, with no significant differences from the curve of larvae fed on rice leaves. The net reproductive rate (Ro, intrinsic rate of increase (rm and finite rate of increase (λ of the population fed on diet were 17.6928, 0.0884 and 1.0924, respectively, and the mean generation time (T and double time (td were prolonged 4.9 d and 1.3 d in comparison with the treatment of rice leaves. Population trend index (I was 3.26, indicating a growing number of the population of C. medinalis fed on artificial diet.

  1. Effects of early horn growth on reproduction and hunting mortality in female chamois.

    Science.gov (United States)

    Rughetti, Marco; Festa-Bianchet, Marco

    2011-03-01

    1. Environmental conditions during early development can affect the growth patterns of vertebrates, influencing future survival and reproduction. In long-lived mammals, females that experience poor environmental conditions early in life may delay primiparity. In female bovids, annual horn growth increments may provide a record of age-specific reproduction and body growth. Horn length, however, may also be a criterion used by hunters in selecting animals to harvest, possibly leading to artificial selection. 2. We studied three populations of chamois (Rupicapra rupicapra) in the western Alps to explore the relationships between female horn length and early growth, age of primiparity and age-specific reproduction. We also compared the risk of harvest to reproductive status and horn length. 3. Early horn growth was positively correlated with body mass in pre-reproductive females and with reproduction in very young and senescent adults. Females with strong early horn growth attained primiparity at an earlier age than those with weak early growth. Horn length did not affect hunter selection, but we found a strong hunter preference for nonlactating females. 4. Our research highlights the persistent effects of early development on reproductive performance in mammals. Moderate sport harvests are unlikely to affect the evolution of phenotypic traits and reproductive strategies in female chamois. A policy of penalizing hunters that harvest lactating females, however, may increase the harvest of 2-year-old females, which have high reproductive potential. © 2010 The Authors. Journal compilation © 2010 British Ecological Society.

  2. Juvenile compensatory growth has negative consequences for reproduction in Trinidadian guppies (Poecilia reticulata).

    Science.gov (United States)

    Auer, Sonya K; Arendt, Jeffrey D; Chandramouli, Radhika; Reznick, David N

    2010-08-01

    Compensatory or 'catch-up' growth may be an adaptive mechanism that buffers the growth trajectory of young organisms from deviations caused by reduced food availability. Theory generally assumes that rapid juvenile compensatory growth impacts reproduction only through its positive effects on age and size at maturation, but potential reproductive costs to juvenile compensatory growth remain virtually unexplored. We used a food manipulation experiment to examine the reproductive consequences of compensatory growth in Trinidadian guppies (Poecilia reticulata). Compensatory growth did not affect adult growth rates, litter production rates or investment in offspring size. However, compensatory growth had negative effects on litter size, independent of the effects of female body length, resulting in a 20% decline in offspring production. We discuss potential mechanisms behind this observed cost to reproduction.

  3. Multiscale Systems Modeling of Male Reproductive Tract ...

    Science.gov (United States)

    The reproductive tract is a complex, integrated organ system with diverse embryology and unique sensitivity to prenatal environmental exposures that disrupt morphoregulatory processes and endocrine signaling. U.S. EPA’s in vitro high-throughput screening (HTS) database (ToxCastDB) was used to profile the bioactivity of 54 chemicals with male developmental consequences across ~800 molecular and cellular features [Leung et al., accepted manuscript]. The in vitro bioactivity on molecular targets could be condensed into 156 gene annotations in a bipartite network. These results highlighted the role of estrogen and androgen signaling pathways in male reproductive tract development, and importantly, broadened the list of molecular targets to include GPCRs, cytochrome-P450s, vascular remodeling proteins, and retinoic acid signaling. A multicellular agent-based model was used to simulate the complex interactions between morphoregulatory, endocrine, and environmental influences during genital tubercle (GT) development. Spatially dynamic signals (e.g., SHH, FGF10, and androgen) were implemented in the model to address differential adhesion, cell motility, proliferation, and apoptosis. Urethral tube closure was an emergent feature of the model that was linked to gender-specific rates of ventral mesenchymal proliferation and urethral plate endodermal apoptosis, both under control of androgen signaling [Leung et al., manuscript in preparation]. A systemic parameter sweep w

  4. [Impact of new trend of ecological environment changes on growth, reproduction and diffusion of Oncomelania hupensis].

    Science.gov (United States)

    Juan, Xie; Li-Yong, Wen

    2016-03-07

    Oncomelania hupensis is the only intermediate host of Schistosoma japonicum , and the growth, reproduction and distribution of O.hupensis play an important role in schistosomiasis prevalence and transmission. This article reviews the influence of the new trend of ecological environment changes on the growth, reproduction and diffusion of the snails.

  5. Genetic relationships among traits related to reproduction and growth of Nelore females.

    Science.gov (United States)

    Eler, J P; Bignardi, A B; Ferraz, J B S; Santana, M L

    2014-09-15

    The objective of the study presented here was to analyze the genetic relationships among heifer pregnancy (HP), age at first calving (AFC), stayability (STAY), average annual productivity of the cow, in kilograms of weaned calf per cow per year (PRODAM), postweaning weight gain (PWG), and hip height (HH) of Nelore females from 12 Brazilian herds. (Co)variance components were obtained by six-trait animal model using Gibbs sampling. The posterior mean of the heritability estimates were 0.37, 0.18, 0.19, 0.16, 0.21, and 0.37 for HP, AFC, STAY, PRODAM, PWG, and HH, respectively. In general, the genetic correlations were strong between traits related to reproduction, for example, -0.85 between HP and AFC, and 0.94 between STAY and PRODAM. Weak genetic correlations were obtained between reproductive and growth traits (absolute values ranging from 0.02 to 0.30). Although weak, the genetic correlations between PWG and reproductive traits were favorable, whereas the genetic correlations between HH and reproductive traits were close to zero and slightly unfavorable for HP, AFC, and STAY. An increase of HH is therefore expected to have little or no negative effect on the reproductive performance of females. The posterior mean of genetic correlation between PWG and HH was moderate (0.50). On the basis of the heritability, genetic correlation estimates, and time to obtain data, HP and PRODAM seems to show the best potential as selection criteria to improve the productive and reproductive performance of Nelore females. In principle, it is possible to select for increased PWG without compromising the reproduction of Nelore females. However, selection for PWG may result in an increase of female HH as a correlated response, a fact that could increase management costs in advanced generations of selection. In the light of the results, all traits studied here can be used as selection criteria and there is no strong evidence of genetic antagonism among traits related to reproduction

  6. A Dynamic Model of Cultural Reproduction

    DEFF Research Database (Denmark)

    Jæger, Mads Meier; Breen, Richard

    2016-01-01

    of study. Their model describes how parents transmit cultural capital to their children and how children convert cultural capital into educational success. It also provides a behavioral framework for interpreting parental investments in cultural capital. The authors review results from existing empirical......The authors draw on Pierre Bourdieu’s theory of cultural reproduction to develop a formal model of the pathways through which cultural capital acts to enhance children’s educational and socioeconomic success. The authors’ approach brings conceptual and empirical clarity to an important area...... research on the role of cultural capital in education to demonstrate the usefulness of their model for interpretative purposes, and they use National Longitudinal Survey of Youth 1979—Children and Young Adults survey data to test some of its implications....

  7. Stochastic ontogenetic growth model

    Science.gov (United States)

    West, B. J.; West, D.

    2012-02-01

    An ontogenetic growth model (OGM) for a thermodynamically closed system is generalized to satisfy both the first and second law of thermodynamics. The hypothesized stochastic ontogenetic growth model (SOGM) is shown to entail the interspecies allometry relation by explicitly averaging the basal metabolic rate and the total body mass over the steady-state probability density for the total body mass (TBM). This is the first derivation of the interspecies metabolic allometric relation from a dynamical model and the asymptotic steady-state distribution of the TBM is fit to data and shown to be inverse power law.

  8. Modeling reproductive decisions with simple heuristics

    Directory of Open Access Journals (Sweden)

    Peter Todd

    2013-10-01

    Full Text Available BACKGROUND Many of the reproductive decisions that humans make happen without much planning or forethought, arising instead through the use of simple choice rules or heuristics that involve relatively little information and processing. Nonetheless, these heuristic-guided decisions are typically beneficial, owing to humans' ecological rationality - the evolved fit between our constrained decision mechanisms and the adaptive problems we face. OBJECTIVE This paper reviews research on the ecological rationality of human decision making in the domain of reproduction, showing how fertility-related decisions are commonly made using various simple heuristics matched to the structure of the environment in which they are applied, rather than being made with information-hungry mechanisms based on optimization or rational economic choice. METHODS First, heuristics for sequential mate search are covered; these heuristics determine when to stop the process of mate search by deciding that a good-enough mate who is also mutually interested has been found, using a process of aspiration-level setting and assessing. These models are tested via computer simulation and comparison to demographic age-at-first-marriage data. Next, a heuristic process of feature-based mate comparison and choice is discussed, in which mate choices are determined by a simple process of feature-matching with relaxing standards over time. Parental investment heuristics used to divide resources among offspring are summarized. Finally, methods for testing the use of such mate choice heuristics in a specific population over time are then described.

  9. Evaluation of growth and reproduction as indicators of soil metal toxicity to the Collembolan, Sinella curviseta

    DEFF Research Database (Denmark)

    Xu, Jie; Ke, Xin; Krogh, Paul Henning

    2009-01-01

    in large numbers of progeny and no significant mortality compared to controls. Adult growth rate decreased for all metal treatments compared to the controls, suggesting that metals affect S. curviseta metabolism and result in slower growth. We showed that reproduction is a slightly more sensitive parameter...... than growth. Since a growth test needs fewer juveniles and takes less time than a reproduction test, we conclude that the two parameters are complementary and could be used for a better ecotoxicological evaluation of contaminant levels. However, relative growth and reproduction sensitivities should......Laboratory studies evaluated the sensitivity of Sinella curviseta Brook (Collembola: Entomobryidae) to selected heavy metals (Cu, Pb and Zn). Survival, reproduction and growth of S. curviseta were determined in a 4-week exposure test in an agricultural soil amended with metals to concentrations...

  10. Dietary L-arginine supplementation enhances placental growth and reproductive performance in sows.

    Science.gov (United States)

    Gao, Kaiguo; Jiang, Zongyong; Lin, Yingcai; Zheng, Chuntian; Zhou, Guilian; Chen, Fang; Yang, Lin; Wu, Guoyao

    2012-06-01

    Suboptimal embryonic/fetal survival and growth remains a significant problem in mammals. Using a swine model, we tested the hypothesis that dietary L-arginine supplementation during gestation may improve pregnancy outcomes through enhancing placental growth and modulating hormonal secretions. Gestating pigs (Yorkshire×Landrace, n=108) were assigned randomly into two groups based on parity and body weight, representing dietary supplementation with 1.0% L-arginine-HCl or 1.7% L-alanine (isonitrogenous control) between days 22 and 114 of gestation. Blood samples were obtained from the ear vein on days 22, 40, 70 and 90 of gestation. On days 40, 70 and 90 of gestation, concentrations of estradiol in plasma were higher (Psupplemented than in control sows. Moreover, arginine supplementation increased (Psupplementation increased (Psupplementation enhanced (Psupplementation during gestation. These results indicate that dietary arginine supplementation beneficially enhances placental growth and the reproductive performance of sows.

  11. Adaptability, growth and reproductive success of the Nile tilapia ...

    African Journals Online (AJOL)

    Despite the high contribution of the introduced Oreochromis niloticus as source of food and additional income to the local community, little has been documented on the adaptability and reproductive success of stocked fish in Ethiopia. This study was therefore, conducted to examine the adaptability and reproductive success ...

  12. Growth Hormone and Reproduction: A Review of Endocrine and Autocrine/Paracrine Interactions

    Science.gov (United States)

    Hull, Kerry L.; Harvey, Steve

    2014-01-01

    The somatotropic axis, consisting of growth hormone (GH), hepatic insulin-like growth factor I (IGF-I), and assorted releasing factors, regulates growth and body composition. Axiomatically, since optimal body composition enhances reproductive function, general somatic actions of GH modulate reproductive function. A growing body of evidence supports the hypothesis that GH also modulates reproduction directly, exerting both gonadotropin-dependent and gonadotropin-independent actions in both males and females. Moreover, recent studies indicate GH produced within reproductive tissues differs from pituitary GH in terms of secretion and action. Accordingly, GH is increasingly used as a fertility adjunct in males and females, both humans and nonhumans. This review reconsiders reproductive actions of GH in vertebrates in respect to these new conceptual developments. PMID:25580121

  13. Growth or reproduction: emergence of an evolutionary optimal strategy

    International Nuclear Information System (INIS)

    Grilli, J; Suweis, S; Maritan, A

    2013-01-01

    Modern ecology has re-emphasized the need for a quantitative understanding of the original ‘survival of the fittest theme’ based on analysis of the intricate trade-offs between competing evolutionary strategies that characterize the evolution of life. This is key to the understanding of species coexistence and ecosystem diversity under the omnipresent constraint of limited resources. In this work we propose an agent-based model replicating a community of interacting individuals, e.g. plants in a forest, where all are competing for the same finite amount of resources and each competitor is characterized by a specific growth–reproduction strategy. We show that such an evolution dynamics drives the system towards a stationary state characterized by an emergent optimal strategy, which in turn depends on the amount of available resources the ecosystem can rely on. We find that the share of resources used by individuals is power-law distributed with an exponent directly related to the optimal strategy. The model can be further generalized to devise optimal strategies in social and economical interacting systems dynamics. (paper)

  14. Exponential growth for self-reproduction in a catalytic reaction network: relevance of a minority molecular species and crowdedness

    Science.gov (United States)

    Kamimura, Atsushi; Kaneko, Kunihiko

    2018-03-01

    Explanation of exponential growth in self-reproduction is an important step toward elucidation of the origins of life because optimization of the growth potential across rounds of selection is necessary for Darwinian evolution. To produce another copy with approximately the same composition, the exponential growth rates for all components have to be equal. How such balanced growth is achieved, however, is not a trivial question, because this kind of growth requires orchestrated replication of the components in stochastic and nonlinear catalytic reactions. By considering a mutually catalyzing reaction in two- and three-dimensional lattices, as represented by a cellular automaton model, we show that self-reproduction with exponential growth is possible only when the replication and degradation of one molecular species is much slower than those of the others, i.e., when there is a minority molecule. Here, the synergetic effect of molecular discreteness and crowding is necessary to produce the exponential growth. Otherwise, the growth curves show superexponential growth because of nonlinearity of the catalytic reactions or subexponential growth due to replication inhibition by overcrowding of molecules. Our study emphasizes that the minority molecular species in a catalytic reaction network is necessary for exponential growth at the primitive stage of life.

  15. 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.

  16. Environmental effects on growth, reproduction, and life-history traits of loggerhead turtles

    NARCIS (Netherlands)

    Marn, Nina; Jusup, Marko; Legović, Tarzan; Kooijman, S. A.L.M.; Klanjšček, Tin

    2017-01-01

    Understanding the relationship between the environmental conditions and life-history traits (such as growth, reproduction, and size at specific life stages) is important for understanding the population dynamics of a species and for constructing adaptable, relevant, and efficient conservation

  17. The nuclear receptor DAF-12 regulates nutrient metabolism and reproductive growth in nematodes.

    Directory of Open Access Journals (Sweden)

    Zhu Wang

    2015-03-01

    Full Text Available Appropriate nutrient response is essential for growth and reproduction. Under favorable nutrient conditions, the C. elegans nuclear receptor DAF-12 is activated by dafachronic acids, hormones that commit larvae to reproductive growth. Here, we report that in addition to its well-studied role in controlling developmental gene expression, the DAF-12 endocrine system governs expression of a gene network that stimulates the aerobic catabolism of fatty acids. Thus, activation of the DAF-12 transcriptome coordinately mobilizes energy stores to permit reproductive growth. DAF-12 regulation of this metabolic gene network is conserved in the human parasite, Strongyloides stercoralis, and inhibition of specific steps in this network blocks reproductive growth in both of the nematodes. Our study provides a molecular understanding for metabolic adaptation of nematodes to their environment, and suggests a new therapeutic strategy for treating parasitic diseases.

  18. Genetic correlations between male reproductive traits and growth traits in growth performance tested Duroc, Landrace and Yorkshire breed boars.

    Science.gov (United States)

    Chang, Hsiu-Luan; Lai, Yung-Yu; Wu, Ming-Che; Sasaki, Osamu

    2017-09-01

    Male-related traits at 180-225 days of age for 6464 grow-finish performance tested boars were measured from 2000 to 2016. Heritability estimates and genetic correlations among average daily gain, feed efficiency, back fat thickness, teat counts, mounting libido, leg locomotion, penile length, sperm motility, sperm concentration and total sperm counts were estimated by VCE software using a multiple traits animal model in each breed. Growth-tested boars had heritability estimates of male reproductive traits in 0.34-0.56 of teat counts, 0.12-0.20 of libido, 0.08-0.12 of locomotion, 0.17-0.58 of penile length, 0.04-0.21 of sperm motility and concentration, 0.17-0.30 of total sperm counts. Total sperm counts were genetically positively correlated with penile length in all breeds. Boars with higher total sperm counts had genetically better libido and locomotion. Genetic correlation between feed efficiency and sperm motility and feed efficiency and sperm concentration were positive in Duroc and negative in Landrace and Yorkshire. Sperm motility and concentration were genetically negatively correlated with average daily gain in Yorkshire. Male reproductive traits of imported breeds could be improved with care in the change of growth traits, especially in Yorkshire. © 2017 Japanese Society of Animal Science.

  19. Mortality affects adaptive allocation to growth and reproduction: field evidence from a guild of body snatchers

    OpenAIRE

    Hechinger Ryan F

    2010-01-01

    Abstract Background The probability of being killed by external factors (extrinsic mortality) should influence how individuals allocate limited resources to the competing processes of growth and reproduction. Increased extrinsic mortality should select for decreased allocation to growth and for increased reproductive effort. This study presents perhaps the first clear cross-species test of this hypothesis, capitalizing on the unique properties offered by a diverse guild of parasitic castrator...

  20. Mortality affects adaptive allocation to growth and reproduction: field evidence from a guild of body snatchers.

    Science.gov (United States)

    Hechinger, Ryan F

    2010-05-07

    The probability of being killed by external factors (extrinsic mortality) should influence how individuals allocate limited resources to the competing processes of growth and reproduction. Increased extrinsic mortality should select for decreased allocation to growth and for increased reproductive effort. This study presents perhaps the first clear cross-species test of this hypothesis, capitalizing on the unique properties offered by a diverse guild of parasitic castrators (body snatchers). I quantify growth, reproductive effort, and expected extrinsic mortality for several species that, despite being different species, use the same species' phenotype for growth and survival. These are eight trematode parasitic castrators-the individuals of which infect and take over the bodies of the same host species-and their uninfected host, the California horn snail. As predicted, across species, growth decreased with increased extrinsic mortality, while reproductive effort increased with increased extrinsic mortality. The trematode parasitic castrator species (operating stolen host bodies) that were more likely to be killed by dominant species allocated less to growth and relatively more to current reproduction than did species with greater life expectancies. Both genders of uninfected snails fit into the patterns observed for the parasitic castrator species, allocating as much to growth and to current reproduction as expected given their probability of reproductive death (castration by trematode parasites). Additionally, species differences appeared to represent species-specific adaptations, not general plastic responses to local mortality risk. Broadly, this research illustrates that parasitic castrator guilds can allow unique comparative tests discerning the forces promoting adaptive evolution. The specific findings of this study support the hypothesis that extrinsic mortality influences species differences in growth and reproduction.

  1. 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...... examples to show how reproductive timing Tc and level R0 are shaped by stage dynamics (individual trait changes), selection on the trait, and parent-offspring phenotypic correlation. We also show how population structure can affect dispersion in reproduction among ages and stages. These macroscopic...... features of the life history determine population growth rate r and reveal a complex interplay of trait dynamics, timing, and level of reproduction. Our results contribute to a new framework of population and evolutionary dynamics in stage-and-age-structured populations....

  2. Reproductive Behavior and Personality Traits of the Five Factor Model

    NARCIS (Netherlands)

    Jokela, Markus; Alvergne, Alexandra; Pollet, Thomas V.; Lummaa, Virpi

    2011-01-01

    We examined associations between Five Factor Model personality traits and various outcomes of reproductive behavior in a sample of 15 729 women and men from the Wisconsin Longitudinal Study (WLS) and Midlife Development in the United States (MIDUS) survey. Personality and reproductive history was

  3. Modelling reproduction of Plutella xylostella L. (Lepidoptera: Plutellidae): climate change may modify pest incidence levels.

    Science.gov (United States)

    Marchioro, C A; Foerster, L A

    2012-08-01

    Temperature is considered to be an important abiotic factor influencing insect reproduction. Despite the importance of Plutella xylostella L. (Lepidoptera: Plutellidae) as a pest of brassicaceous crops worldwide, the effects of temperature on its reproduction are not well understood. We evaluated the effect of constant temperatures ranging from 10 to 32.5°C on the reproduction of P. xylostella and developed an oviposition model for the species. The model combined temperature-dependent parameters of total fecundity, age-specific oviposition rate and age-specific survival. Additionally, we modelled population growth as a function of temperature. The estimated parameters allowed us to discuss the possible consequences of global warming on P. xylostella distribution. Temperature affected the length of pre-oviposition after adult emergence, oviposition period, longevity, total fecundity and egg viability. The model predicted that both daily egg production and length of oviposition period decreased at temperatures below 15°C and above 25°C. Population growth increased linearly with temperature in a range from 10°C to 25°C; however, the model predicted a reduction in population growth at temperatures above 28.6°C. Data suggested that temperature plays a critical role in P. xylostella reproduction, and subtle differences in average temperature could have an impact on its population growth. This is especially important in the context of global climate change, which in turn could alter the distribution and abundance of the pest in some regions of the world.

  4. Growth and reproduction of the mangrove crab Goniopsis cruentata (Latreille, 1803 (Crustacea: Decapoda: Grapsidae in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Carla R.G. Reis

    2015-06-01

    Full Text Available Goniopsis cruentata is a common semi-terrestrial crab in Brazilian mangroves and an important fishery resource for traditional communities in the northeastern Brazilian coast. Aiming to contribute to the knowledge about the species, this study evaluated the carapace width and weight growth curves, the relative growth of weight versus carapace width, and the temporal variation of gonadosomatic and hepatosomatic indices for the species. A total of 524 crabs were collected in a mangrove area of Ubatuba municipality, state of São Paulo. The growth-curves parameters and longevity (tmax were estimated for males (CW∞=50.6 mm, WE=56.4 g, k=2.24, t0=0.003631502 year-1, tmax=1.3 years and females (CW∞=50.7 mm, WE∞=58.8 g, k=2.50, t0=0.003247209 year-1, tmax=1.2 years. The age at onset of sexual maturity was 0.23 years for both genders. The weight-growth model was isometric for the immature developmental stages and allometric negative for adults. The species exhibited a continuous reproduction, with breeding peaks in spring and summer months. The weight dynamics of gonads and hepatopancreas were not clearly related. The growth and reproductive patterns indicated that Goniopsis cruentata has a life-history that prioritizes reproduction instead of survival. The species exhibited some of the highest growth rates and lowest longevity estimates reported for brachyuran species in Brazil.

  5. Ozone affects gas exchange, growth and reproductive development in Brassica campestris (Wisconsin fast plants).

    Science.gov (United States)

    Black, V J; Stewart, C A; Roberts, J A; Black, C R

    2007-01-01

    Exposure to ozone (O(3)) may affect vegetative and reproductive development, although the consequences for yield depend on the effectiveness of the compensatory processes induced. This study examined the impact on reproductive development of exposing Brassica campestris (Wisconsin Fast Plants) to ozone during vegetative growth. Plants were exposed to 70 ppb ozone for 2 d during late vegetative growth or 10 d spanning most of the vegetative phase. Effects on gas exchange, vegetative growth, reproductive development and seed yield were determined. Impacts on gas exchange and foliar injury were related to pre-exposure stomatal conductance. Exposure for 2 d had no effect on growth or reproductive characteristics, whereas 10-d exposure reduced vegetative growth and reproductive site number on the terminal raceme. Mature seed number and weight per pod and per plant were unaffected because seed abortion was reduced. The observation that mature seed yield per plant was unaffected by exposure during the vegetative phase, despite adverse effects on physiological, vegetative and reproductive processes, shows that indeterminate species such as B. campestris possess sufficient compensatory flexibility to avoid reductions in seed production.

  6. POPULATION AND REPRODUCTIVE GROWTH OF ROE DEER, Capreolus capreolus Linnaeus, 1758. IN THE HUNTING GROUND "CREPOLJSKO"

    Directory of Open Access Journals (Sweden)

    Enad Korjenić

    2013-03-01

    Full Text Available Field research of population and reproductive growth of roe deer, Capreolus capreolus Linnaeus, 1758. in the hunting ground "Crepoljsko" lasted from January to December 2009. In the studied hunting ground two habitats (sites of roe deer Nahorevo and Bukovik have been registered with the estimated area of 1900 ha. Nahorevo covers, approximately 800 ha, and Bukovik 1100 ha. The total number of roe deer individuals in the "Crepoljsko" estimated to 103 individuals. In hunting ground Nahorevo 42 individual of roe deer of various age structure have been documented. Absolute reproductive growth of deer in this study area was six individuals or 45% of the expected (theoretical reproductive growth (60%. In hunting ground Bukovik 61 individuals have been found. Absolute reproductive growth was 9 individuals which makes 49% of theoretical reproductive growth. On the basis these results it could be concluded that the investigated habitats (sites have suitable conditions for this attractive hunting deer, as wall as for the development of hunting tourism and education. Key words: deer, population, reproduction, habitat

  7. Growth and reproductive patterns of Undaria pinnatifida sporophytes in a cultivation farm in Busan, Korea.

    Science.gov (United States)

    Choi, Han Gil; Kim, Young Sik; Lee, Soon Jeong; Nam, Ki Wan

    2007-04-01

    Monthly growth and reproduction of Undaria pinnatifida sporophytes were examined over a period of 5 months in a cultivation farm in Korea. A total of 11 characters of Undaria were measured to determine a reliable morphological character representing its growth and reproduction. Plant weight of Undaria sporophytes increased steadily over the experimental period, but it increased in four different ways. Undaria pinnatifida increased body weight by growth in length and width (October-early December), and by growth in width with the thickening of blade and stipe when sporophytes began to be fertile (December-January). In the middle of January, growth in length and width had almost stopped with the maturation of Undaria sporophytes. Finally, the weight of Undaria increased again by growth in width at the end of February. Present results indicate that Undaria sporophytes increase body weight by growth in length and width at different times, and the relationship between reproduction and vegetative growth is exclusive. Plant weight was positively correlated and fitted well with stipe width and blade width. The blade of Undaria was very thin (ca. 254 mum) and breakable by wave action, but its stipe was strong and relatively thick (ca. 8.7 mm). Furthermore, the fertility of U. pinnatifida was fitted better with stipe width than blade width. Thus, we suggest that the stipe width is the most feasible character with which to estimate the growth and reproduction of U. pinnatifida sporophytes in the cultivation farm.

  8. Trends in clinical reproductive medicine research : 10 years of growth

    NARCIS (Netherlands)

    Aleixandre-Benavent, Rafael; Simon, Carlos; Fauser, Bart C J M|info:eu-repo/dai/nl/071281932

    2015-01-01

    Objective To study the most important metrics of publication in the field of reproductive medicine over the decade 2003-2012 to aid in discerning the clinical, social, and epidemiologic implications of this relatively new but rapidly emerging area in medical sciences. Design Bibliometric analysis of

  9. Growth and Reproductive Performance of Rabbits Fed Mistletoe ...

    African Journals Online (AJOL)

    Ten (10) rabbit does of mixed breeds aged between 5 – 6 months were used to study the effect of feeding mistletoe on feed intake, body weight and reproductive performance of rabbits. Following a pre - treatment period of two weeks during which the does were allowed to acclimatize to the environment, they were randomly ...

  10. Models to study gravitational biology of Mammalian reproduction

    Science.gov (United States)

    Tou, Janet; Ronca, April; Grindeland, Richard; Wade, Charles

    2002-01-01

    Mammalian reproduction evolved within Earth's 1-g gravitational field. As we move closer to the reality of space habitation, there is growing scientific interest in how different gravitational states influence reproduction in mammals. Habitation of space and extended spaceflight missions require prolonged exposure to decreased gravity (hypogravity, i.e., weightlessness). Lift-off and re-entry of the spacecraft are associated with exposure to increased gravity (hypergravity). Existing data suggest that spaceflight is associated with a constellation of changes in reproductive physiology and function. However, limited spaceflight opportunities and confounding effects of various nongravitational factors associated with spaceflight (i.e., radiation, stress) have led to the development of ground-based models for studying the effects of altered gravity on biological systems. Human bed rest and rodent hindlimb unloading paradigms are used to study exposure to hypogravity. Centrifugation is used to study hypergravity. Here, we review the results of spaceflight and ground-based models of altered gravity on reproductive physiology. Studies utilizing ground-based models that simulate hyper- and hypogravity have produced reproductive results similar to those obtained from spaceflight and are contributing new information on biological responses across the gravity continuum, thereby confirming the appropriateness of these models for studying reproductive responses to altered gravity and the underlying mechanisms of these responses. Together, these unique tools are yielding new insights into the gravitational biology of reproduction in mammals.

  11. The effects of epoxiconazole and α-cypermethrin on Daphnia magna growth, reproduction, and offspring size

    DEFF Research Database (Denmark)

    Gottardi, Michele; Birch, Michala Rosa; Dalhoff, Kristoffer

    2017-01-01

    of sublethal concentrations of epoxiconazole and α-cypermethrin and their mixture on growth, reproduction, and in vivo cytochrome P450 activity of the aquatic crustacean Daphnia magna over 42 d. Continuous exposure to nonlethal concentrations of α-cypermethrin at 20 ng/L negatively affected adult growth......-cypermethrin up to 3-fold leading to decreased growth, cytochrome P450 activity, and reproduction of D. magna within the first 14 d of exposure. After 14 d, the synergistic interactions disappeared. The reported effects, although lacking direct negative consequence in the long term, might have cumulative toxicity...

  12. Effect of stocking density on growth, maturity, fecundity, reproductive ...

    African Journals Online (AJOL)

    Jane

    2011-08-29

    Aug 29, 2011 ... weeks. Growth and specific growth rates were inversely proportional to stocking density (P=0.0555, r=0.944; P=0.0395, r=0.960 ... of pond farming conditions, resistance to diseases, high survival and growth rate (Onumah et al., ..... Fertilized eggs were found to hatch after 2 to 3 days of incubation. Hatched ...

  13. Cancer susceptibility and reproductive trade-offs: a model of the evolution of cancer defences.

    Science.gov (United States)

    Boddy, Amy M; Kokko, Hanna; Breden, Felix; Wilkinson, Gerald S; Aktipis, C Athena

    2015-07-19

    The factors influencing cancer susceptibility and why it varies across species are major open questions in the field of cancer biology. One underexplored source of variation in cancer susceptibility may arise from trade-offs between reproductive competitiveness (e.g. sexually selected traits, earlier reproduction and higher fertility) and cancer defence. We build a model that contrasts the probabilistic onset of cancer with other, extrinsic causes of mortality and use it to predict that intense reproductive competition will lower cancer defences and increase cancer incidence. We explore the trade-off between cancer defences and intraspecific competition across different extrinsic mortality conditions and different levels of trade-off intensity, and find the largest effect of competition on cancer in species where low extrinsic mortality combines with strong trade-offs. In such species, selection to delay cancer and selection to outcompete conspecifics are both strong, and the latter conflicts with the former. We discuss evidence for the assumed trade-off between reproductive competitiveness and cancer susceptibility. Sexually selected traits such as ornaments or large body size require high levels of cell proliferation and appear to be associated with greater cancer susceptibility. Similar associations exist for female traits such as continuous egg-laying in domestic hens and earlier reproductive maturity. Trade-offs between reproduction and cancer defences may be instantiated by a variety of mechanisms, including higher levels of growth factors and hormones, less efficient cell-cycle control and less DNA repair, or simply a larger number of cell divisions (relevant when reproductive success requires large body size or rapid reproductive cycles). These mechanisms can affect intra- and interspecific variation in cancer susceptibility arising from rapid cell proliferation during reproductive maturation, intrasexual competition and reproduction. © 2015 The Author

  14. Cancer susceptibility and reproductive trade-offs: a model of the evolution of cancer defences

    Science.gov (United States)

    Boddy, Amy M.; Kokko, Hanna; Breden, Felix; Wilkinson, Gerald S.; Aktipis, C. Athena

    2015-01-01

    The factors influencing cancer susceptibility and why it varies across species are major open questions in the field of cancer biology. One underexplored source of variation in cancer susceptibility may arise from trade-offs between reproductive competitiveness (e.g. sexually selected traits, earlier reproduction and higher fertility) and cancer defence. We build a model that contrasts the probabilistic onset of cancer with other, extrinsic causes of mortality and use it to predict that intense reproductive competition will lower cancer defences and increase cancer incidence. We explore the trade-off between cancer defences and intraspecific competition across different extrinsic mortality conditions and different levels of trade-off intensity, and find the largest effect of competition on cancer in species where low extrinsic mortality combines with strong trade-offs. In such species, selection to delay cancer and selection to outcompete conspecifics are both strong, and the latter conflicts with the former. We discuss evidence for the assumed trade-off between reproductive competitiveness and cancer susceptibility. Sexually selected traits such as ornaments or large body size require high levels of cell proliferation and appear to be associated with greater cancer susceptibility. Similar associations exist for female traits such as continuous egg-laying in domestic hens and earlier reproductive maturity. Trade-offs between reproduction and cancer defences may be instantiated by a variety of mechanisms, including higher levels of growth factors and hormones, less efficient cell-cycle control and less DNA repair, or simply a larger number of cell divisions (relevant when reproductive success requires large body size or rapid reproductive cycles). These mechanisms can affect intra- and interspecific variation in cancer susceptibility arising from rapid cell proliferation during reproductive maturation, intrasexual competition and reproduction. PMID:26056364

  15. The reproductive value in distributed optimal control models.

    Science.gov (United States)

    Wrzaczek, Stefan; Kuhn, Michael; Prskawetz, Alexia; Feichtinger, Gustav

    2010-05-01

    We show that in a large class of distributed optimal control models (DOCM), where population is described by a McKendrick type equation with an endogenous number of newborns, the reproductive value of Fisher shows up as part of the shadow price of the population. Depending on the objective function, the reproductive value may be negative. Moreover, we show results of the reproductive value for changing vital rates. To motivate and demonstrate the general framework, we provide examples in health economics, epidemiology, and population biology.

  16. Antiprogestin mifepristone inhibits the growth of cancer cells of reproductive and non-reproductive origin regardless of progesterone receptor expression

    Directory of Open Access Journals (Sweden)

    Ortbahn Casey T

    2011-05-01

    Full Text Available Abstract Background Mifepristone (MF has been largely used in reproductive medicine due to its capacity to modulate the progesterone receptor (PR. The study of MF has been expanded to the field of oncology; yet it remains unclear whether the expression of PR is required for MF to act as an anti-cancer agent. Our laboratory has shown that MF is a potent inhibitor of ovarian cancer cell growth. In this study we questioned whether the growth inhibitory properties of MF observed in ovarian cancer cells would translate to other cancers of reproductive and non-reproductive origin and, importantly, whether its efficacy is related to the expression of cognate PR. Methods Dose-response experiments were conducted with cancer cell lines of the nervous system, breast, prostate, ovary, and bone. Cultures were exposed to vehicle or increasing concentrations of MF for 72 h and analysed for cell number and cell cycle traverse, and hypodiploid DNA content characteristic of apoptotic cell death. For all cell lines, expression of steroid hormone receptors upon treatment with vehicle or cytostatic doses of MF for 24 h was studied by Western blot, whereas the activity of the G1/S regulatory protein Cdk2 in both treatment groups was monitored in vitro by the capacity of Cdk2 to phosphorylate histone H1. Results MF growth inhibited all cancer cell lines regardless of tissue of origin and hormone responsiveness, and reduced the activity of Cdk2. Cancer cells in which MF induced G1 growth arrest were less susceptible to lethality in the presence of high concentrations of MF, when compared to cancer cells that did not accumulate in G1. While all cancer cell lines were growth inhibited by MF, only the breast cancer MCF-7 cells expressed cognate PR. Conclusions Antiprogestin MF inhibits the growth of different cancer cell lines with a cytostatic effect at lower concentrations in association with a decline in the activity of the cell cycle regulatory protein Cdk2, and

  17. Symbiotic regulation of plant growth, development and reproduction

    Science.gov (United States)

    Russell J. Rodriguez; D. Carl Freeman; E. Durant McArthur; Yong Ok Kim; Regina S. Redman

    2009-01-01

    The growth and development of rice (Oryzae sativa) seedlings was shown to be regulated epigenetically by a fungal endophyte. In contrast to un-inoculated (nonsymbiotic) plants, endophyte colonized (symbiotic) plants preferentially allocated resources into root growth until root hairs were well established. During that time symbiotic roots expanded at...

  18. Reconciling contradictory findings of herbivore impacts on spotted knapweed (Centaurea stoebe) growth and reproduction.

    Science.gov (United States)

    Knochel, David G; Seastedt, Timothy R

    2010-10-01

    Substantial controversy surrounds the efficacy of biological control insects to reduce densities of Centaurea stoebe, a widespread, aggressive invasive plant in North America. We developed a graphical model to conceptualize the conditions required to explain the current contradictory findings, and then employed a series of manipulations to evaluate C. stoebe responses to herbivores. We manipulated soil nitrogen and competition in a field population and measured attack rates of a foliage and seed feeder (Larinus minutus), two gall flies (Urophora spp.), and a root feeder (Cyphocleonus achates), as well as their effects on the growth and reproduction of C. stoebe. Nitrogen limitation and competing vegetation greatly reduced C. stoebe growth. L. minutus most intensively reduced seed production in low-nitrogen soils, and removal of neighboring vegetation increased Larinus numbers per flower head and the percentage of flowers attacked by 15% and 11%, respectively. Cyphocleonus reduced flower production and aboveground biomass over two years, regardless of resources or competition. Our results, in conjunction with other published studies, demonstrate that positive, neutral, and negative plant growth responses to herbivory can be generated. However, under realistic field conditions and in the presence of multiple herbivores, our work repudiates earlier studies that indicate insect herbivores increase C. stoebe dominance.

  19. Reproduction and vegetative growth in the dioecious shrub Acer barbinerve in temperate forests of Northeast China.

    Science.gov (United States)

    Wang, Juan; Zhang, Chunyu; Gadow, Klaus V; Cheng, Yanxia; Zhao, Xiuhai

    2015-06-01

    Trade-off in dioecious plant. The trade-off between reproduction, vegetative growth and maintenance is a major issue in the life history of an organism and a record of the process which is producing the largest possible number of living offspring by natural selection. Dioecious species afford an excellent opportunity for detecting such possible trade-offs in resource allocation. In this study, we selected the dioecious shrub Acer barbinerve to examine possible trade-offs between reproduction and vegetative growth in both genders at different modular levels during three successive years. Reproductive and vegetative biomass values were assessed during successive years to evaluate their intra-annual and inter-annual trade-offs. These trade-offs were examined at shoot, branch and shrub modular levels in Acer barbinerve shrubs. An intra-annual trade-off was detected at the shoot level for both genders in 2011 and 2012. Both males and females showed a negative correlation between reproduction and vegetative growth, but this was more prominent in males. For the females of the species, inter-annual trade-offs were only found at branch and shrub levels. Slightly negative correlations in females were detected between the reproduction in 2012 and the reproduction in the two previous years. The gender ratio was significantly male biased during the three successive years of our investigation. Females had higher mortality rates in the larger diameter classes, both in 2011 and 2012. This study revealed a clear trade-off between reproduction and vegetative growth in Acer barbinerve, but results varied between males and females. The degree of autonomy of the different modular levels may affect the ability to detect such trade-offs.

  20. Sex-related differences in reproductive allocation, growth, defense and herbivory in three dioecious neotropical palms.

    Directory of Open Access Journals (Sweden)

    Verónica Cepeda-Cornejo

    2010-03-01

    Full Text Available Frequently, in dioecious plants, female plants allocate more resources to reproduction than male plants. Therefore it is expected that asymmetrical allocation to reproduction may lead to a reproduction-growth tradeoff, whereby female plants grow less than male plants, but invest more in defenses and thus experience lower herbivory than male plants.We tested these expectations by comparing resource allocation to reproduction, growth and defense and its consequences on herbivory in three sympatric dioecious Chamaedorea palms (C. alternans, C. pinnatifrons and C. ernesti-augusti using a pair-wise design (replicated male/female neighboring plants in a Mexican tropical rain forest. Our findings support the predictions. Biomass allocation to reproduction in C. pinnatifrons was 3-times higher in female than male plants, consistent with what is known in C. alternans and C. ernesti-augusti. Growth (height and leaf production rate and biomass production was higher in male plants of all three species. Female plants of the three species had traits that suggest greater investment in defense, as they had 4-16% tougher leaves, and 8-18% higher total phenolic compounds concentration. Accordingly, female plants sustained 53-78% lower standing herbivory and 49-87% lower herbivory rates than male plants.Our results suggests that resource allocation to reproduction in the studied palms is more costly to female plants and this leads to predictable intersexual differences in growth, defense and herbivory. We conclude that resource allocation to reproduction in plants can have important consequences that influence their interaction with herbivores. Since herbivory is recognized as an important selective force in plants, these results are of significance to our understanding of plant defense evolution.

  1. QSAR Models for Reproductive Toxicity and Endocrine Disruption Activity

    Directory of Open Access Journals (Sweden)

    Marjan Vračko

    2010-03-01

    Full Text Available Reproductive toxicity is an important regulatory endpoint, which is required in registration procedures of chemicals used for different purposes (for example pesticides. The in vivo tests are expensive, time consuming and require large numbers of animals, which must be sacrificed. Therefore an effort is ongoing to develop alternative In vitro and in silico methods to evaluate reproductive toxicity. In this review we describe some modeling approaches. In the first example we describe the CAESAR model for prediction of reproductive toxicity; the second example shows a classification model for endocrine disruption potential based on counter propagation artificial neural networks; the third example shows a modeling of relative binding affinity to rat estrogen receptor, and the fourth one shows a receptor dependent modeling experiment.

  2. Role of rice PPS in late vegetative and reproductive growth.

    Science.gov (United States)

    Tanaka, Nobuhiro; Itoh, Jun-Ichi; Nagato, Yasuo

    2012-01-01

    The rice peter pan syndrome-1 (pps-1) mutant shows a prolonged juvenile phase and early flowering. Although the early vegetative phase and flowering time of pps-1 have been closely examined, the phenotypes in the late vegetative and reproductive phases are not yet well understood. In the ninth leaf blade of pps-1, the relative length of the midrib was comparable to the sixth leaf blade of wild-type. Moreover, pps-1 had a small inflorescence meristem and small panicles. These phenotypes indicate that in pps-1 the juvenile phase coexists with the late vegetative phase, resulting in small panicles. Gibberellin is known to promote the juvenile-adult phase transition. d18-k is dwarf and has a prolonged juvenile phase. Double mutant (d18-k pps-1) showed the same phenotype as the pps-1, indicating that PPS is upstream of GA biosynthetic genes.

  3. Impact of tail-nipping on mortality, growth and reproduction of Arenicola marina

    Science.gov (United States)

    Bergman, Magda J. N.; Van Der Veer, Henk W.; Karczmarski, Leszek

    The impact of predation by amputation of regenerating body parts (tail tips) of the lugworm Arenicola marina on species mortality, growth and reproduction has been studied under laboratory conditions by the artificial removal of tail tips at different frequencies. The loss of body weight by amputation was not compensated for by an increased growth. Within a wide range of amputation frequencies, total growth (body growth + amount of tail tip amputated) and reproduction of the lugworm were not affected. Also, both egg development and amount of energy stored in reproduction remained the same. Only at the highest frequency of amputation (once a week) did total growth decrease in the course of time, resulting even in a loss of body weight. The amount of energy stored in reproduction was also significantly less at the highest rate of amputation. Lugworms appeared to be unable to sustain this high level of amputation and the anaerobic sediment conditions in the cuvettes suggest a reduced pumping activity and food intake. Mortality in this group was also higher than in the other groups. The consequences of tail-nipping by flatfish for A. marina in the field situation are discussed.

  4. reproduction

    African Journals Online (AJOL)

    and research, such as human reproductive cloning.“ However, despite advances in ART the proportion of ... religions such as Islam completely forbid them, and in many countries there is strict regulation of treatment. Although sperm cryopreservation in humans was introduced in 1953,13 sperm donation commenced using.

  5. A demographic projection of the contribution of assisted reproductive technologies to world population growth.

    Science.gov (United States)

    Faddy, Malcolm J; Gosden, Matthew D; Gosden, Roger G

    2018-04-01

    Enormous unmet needs for infertility treatment exist because access to assisted reproductive technologies is demographically skewed. Since the first IVF baby in 1978, the number of people conceived by reproductive technology has grown much faster than expected, reaching several million today and rapidly approaching 0.1% of the total world population. As more patients build families, and their children in turn become parents, the number owing their existence to assisted reproductive technologies, either directly or indirectly, will expand tremendously in future decades, but no attempts have been made hitherto to project the magnitude. We have projected growth to the year 2100, along with the fractional contribution to world population. The chief variable driving growth is access to fertility services. If it stagnates at current levels of about 400,000 babies per year, an estimated 157 million people alive at the end of the century will owe their lives to assisted reproductive technologies (1.4% of global population), but at an arbitrary upper limit of 30,000 extra births annually there will be 394 million additional people alive (3.5%). As the conquest of infertility continues, individuals who owe their lives to assisted reproductive technologies will quietly make a significant contribution to demographic growth as well as social progress. Copyright © 2018. Published by Elsevier Ltd.

  6. Growth and development of the reproductive organs of female ...

    African Journals Online (AJOL)

    The variation in the weight of the ovary probably reflects differences in the laying pattern of individuals, and this lends itself to simulating the ovulatory cycle and consequently gaining a better understanding of the process, which would in turn aid in determining the requirement for the nutrients responsible for the growth of ...

  7. Reproductive biology and growth of the yellowbelly rockcod ...

    African Journals Online (AJOL)

    Other studies indicate that E. marginatus aggregate for spawning, and tagging work has shown that they exhibit high site fidelity. The life history of the species indicates that it is vulnerable to overexploitation. Keywords: grouper, growth, hermaphroditism, protogyny, Serranidae African Journal of Marine Science 2006, 28(1): ...

  8. AGE GROWTH AND ASPECTS OF REPRODUCTION OF THE ...

    African Journals Online (AJOL)

    catches. The time of annulus formation was established from otolith edge examinations. Two lones. ... Research on the mackerel was initiated during 1971 by the Sea Fisheries Branch, Depart- ment of Industries, Sea ... Fitch (1951) investigated the growth of S.japonicus in the Pacific Ocean off the west coast of the United ...

  9. Age, growth and aspects of reproduction of the mackerel Scomber ...

    African Journals Online (AJOL)

    The age and growth of the mackerel were determined from 1742 otoliths collected from commercial catches. The time of annulus formation was established from otolith edge examinations. Two zones. one opaque and one hyaline, are laid down during a year. The distance of each annulus from the nucleus of the otolith was ...

  10. Serum insulin-like growth factor-I (IGF-I) and growth in children born after assisted reproduction

    DEFF Research Database (Denmark)

    Kai, Claudia Mau; Main, Katharina M; Andersen, Anders Nyboe

    2006-01-01

    cohorts was normal. Our findings of subtle differences in target height attainment and serum IGF-I levels between infants born after assisted reproduction techniques and controls may not be clinically significant. However, these observations indicate that further systematic follow-up of growth and puberty......CONTEXT: Concern has been raised about the safety of assisted reproduction techniques for the offspring. OBJECTIVES: The objective of the study was to investigate postnatal growth and growth factors in children born after intra-cytoplasmatic sperm injection (ICSI) and in vitro fertilization (IVF......). DESIGN: The study had two cohorts: a population-based longitudinal infant cohort 0-36 months [236 ICSI, 173 IVF, 1530 naturally conceived (NC)], and a cross-sectional child cohort at 5 yr (68 ICSI, 67 IVF, 70 NC). INTERVENTION: Anthropometrical measurements were made at birth, 3, 18, 36 (infant cohort...

  11. Latitudinal trends in the growth and reproductive seasonality of Delesseria sanguinea, Membranoptera alata, and Phycodrys rubens (Rhodophyta)

    NARCIS (Netherlands)

    Molenaar, FJ; Breeman, AM

    The seasonality of Delesseria sanguinea, Membranoptera alata, and Phycodrys rubens (Rhodophyta) was studied at Helgoland (North Sea, Germany) and Roscoff (Brittany, France). Plants were collected at bimonthly intervals, and growth and reproduction were monitored. Growth of blades was observed mainly

  12. Modeling microbial growth and dynamics.

    Science.gov (United States)

    Esser, Daniel S; Leveau, Johan H J; Meyer, Katrin M

    2015-11-01

    Modeling has become an important tool for widening our understanding of microbial growth in the context of applied microbiology and related to such processes as safe food production, wastewater treatment, bioremediation, or microbe-mediated mining. Various modeling techniques, such as primary, secondary and tertiary mathematical models, phenomenological models, mechanistic or kinetic models, reactive transport models, Bayesian network models, artificial neural networks, as well as agent-, individual-, and particle-based models have been applied to model microbial growth and activity in many applied fields. In this mini-review, we summarize the basic concepts of these models using examples and applications from food safety and wastewater treatment systems. We further review recent developments in other applied fields focusing on models that explicitly include spatial relationships. Using these examples, we point out the conceptual similarities across fields of application and encourage the combined use of different modeling techniques in hybrid models as well as their cross-disciplinary exchange. For instance, pattern-oriented modeling has its origin in ecology but may be employed to parameterize microbial growth models when experimental data are scarce. Models could also be used as virtual laboratories to optimize experimental design analogous to the virtual ecologist approach. Future microbial growth models will likely become more complex to benefit from the rich toolbox that is now available to microbial growth modelers.

  13. Modeling Urban Fire Growth,

    Science.gov (United States)

    Nuclear explosion damage, *Explosion effects, *Fires, *Flame propagation, Growth (General), Area coverage, Ignition, Combustion, Casualties...Computerized simulation, Predictions, Countermeasures, Fire suppression, Damage assessment, Urban areas, Vulnerability, Data acquisition, Methodology, Symposia

  14. Effect of mid-summer haying on growth and reproduction in prairie forbs

    Science.gov (United States)

    Becky Begay; Helen M. Alexander; Erin Questad

    2011-01-01

    Mid-summer haying is a common management practice for prairies; plant species could differ in the effect of haying on subsequent growth and reproduction. We examined the effect of haying on prairie species by performing a clipping experiment. For each of seven species, sixteen plants were chosen and half were randomly assigned to a clipping treatment and half to a...

  15. Effect of Diet on Growth and Reproduction of the African Giant Snail ...

    African Journals Online (AJOL)

    Aspects of growth and reproduction were studied in a total of 360 specimens of Archachatina marginata suturalis cultured in four dietary regimes, as follows: Group A – paw-paw (Carica papaya) leaves + powdered calcium carbonate; Group B – cocoyam (Xanthosoma sagittifolium) leaves + powdered calcium carbonate; ...

  16. Predicting the height growth of oak species (Quercus) reproduction over a 23-year period following clearcutting

    Science.gov (United States)

    J. Travis Swaim; Daniel C. Dey; Michael R. Saunders; Dale R. Weigel; Christopher D. Thornton; John M. Kabrick; Michael A. Jenkins

    2016-01-01

    We resampled plots from a repeated measures study implemented on the Hoosier National Forest (HNF) in southern Indiana in 1988 to investigate the influence of site and seedling physical attributes on height growth and establishment success of oak species (Quercus spp.) reproduction in stands regenerated by the clearcut method. Before harvest, an...

  17. Patterns of Geographic Synchrony in Growth and Reproduction of Oaks Within California and Beyond

    Science.gov (United States)

    Walter D. Koenig; Johannes M.H. Knops

    1997-01-01

    We measured patterns of spatial synchrony in growth and reproduction by oaks using direct acorn surveys, published data on acorn production, and tree-ring chronologies. The two data sets involving acorn production both indicate that acorn crops are detectably synchronous over areas of at least 500 to 1,000 km not only within individual species but among species that...

  18. Influence of green grass-based diets on growth and reproductive performance in dairy heifers

    DEFF Research Database (Denmark)

    Habib, M. R.; Rashid, M. H.; Islam, M. A.

    2018-01-01

    The objective of this study was to monitor the changes in growth, dry matter intake, and blood profiles (nutrition and reproductive hormones) of dairy heifers in response to green grass-based diets. Twelve crossbred heifers were equally divided into group 1: rice straw and concentrate; group 2...

  19. Diet quality impact on growth, reproduction, and digestive activity in .i.Brachionus calyciflorus./i

    Czech Academy of Sciences Publication Activity Database

    Štrojsová, Martina; Nedoma, Jiří; Seďa, Jaromír; Vrba, Jaroslav

    2008-01-01

    Roč. 30, č. 10 (2008), s. 1123-1131 ISSN 0142-7873 R&D Projects: GA AV ČR(CZ) IAA600170602 Institutional research plan: CEZ:AV0Z60170517 Keywords : Brachionus * phosphorus limitation * growth * reproduction * phosphatase Subject RIV: EG - Zoology Impact factor: 1.707, year: 2008

  20. Growth, development, reproductive competence and adult behaviour of Spodoptera litura (Lepidoptera: Noctuidae) reared on different diets

    International Nuclear Information System (INIS)

    Seth, R.K.; Sharma, V.P.

    2002-01-01

    Spodoptera litura was reared on natural food (castor leaves, Ricinus communis) and on a several semi-synthetic diets using quasi mass rearing techniques. The effect of the different diets and rearing regimes on S. litura growth, development, reproductive competence and adult behaviour was measured. Spodoptera litura reared from a modified chickpea-based diet provided the greatest growth index and index of adequacy. These studies were conducted as a prerequisite for the evaluation of F 1 sterility technique. (author)

  1. Sexual-Reproductive Health Belief Model of college students

    Directory of Open Access Journals (Sweden)

    Masoomeh Simbar

    2004-09-01

    Full Text Available Sexual- reproductive health of youth is one of the most unknown aspects of our community, while the world, including our country is faced with the risk of AIDS spreading. The aim of this study was to describe Health Belief Model (HBM of the students about sexual-reproductive health behaviors and evaluate the ability of the model in predicting related behaviors. By using quota sampling, 1117 male and female students of Qazvin Medical Science and International universities were included in the study in 1991. A self-completed questionnaire was prepared containing close questions based on HBM components including perceived threats (susceptibility and severity of related diseases, perceived reproductive benefits and barriers and self efficacy of youth about reproductive health. A total of 645 of participants were female and 457 were male (Mean age 21.4±2.4 and 22.7±3.5, respectively. The Health Belief Model of the students showed that they perceived a moderate threat for AIDS and venereal diseases and their health outcomes. Most of them perceived the benefits of reproductive health behaviors. They believed that the ability of youth in considering reproductive health is low or moderate. However, they noted to some barriers for spreading of reproductive health in youth including inadequacy of services. Boys felt a higher level of threat for acquiring the AIDS and venereal diseases in compare to girls, but girls had a higher knowledge about these diseases and their complications. The Health Belief Model of the students with premarital intercourse behavior was not significantly different with the students without this behavior (Mann-Withney, P<0.05. Female students and the students without the history of premarital intercourse had significantly more positive attitude towards abstinence, comparing to male students and students with the history of premarital intercourse, respectively (Mann-Withney, P<0.05. Seventy five percent of students believed in

  2. The influence of thymol+DMSO on survival, growth and reproduction of Bradybaena similaris (Mollusca: Bradybaenidae

    Directory of Open Access Journals (Sweden)

    Paula Ferreira

    2011-04-01

    Full Text Available Bradybaena similaris (Férussac, 1821, commonly known as the Asian trampsnail, is a terrestrial snail native to Asia, introduced in other regions of the world. In Brazil, populations of this land snail are distributed from the state of Amapá in the North to Rio Grande do Sul in the South. This species acts as an intermediate host for parasites and is a difficult-to-control agricultural pest as well, causing great losses to crops and ornamental plant cultivation. This land snail is easily reared in the laboratory and has been successfully used as a biological model in studies that aim at verifying molluscicidal effects of plant extracts. Several studies have demonstrated that B. similaris, like many other species of land and freshwater snails, is physiologically adapted to survival over transitory unfavorable environmental conditions. Moreover, this species seems to have a life history strategy characterized by a short life span and a maximal opportunistic reproductive effort during transient favorable periods. Such biological features may potentially lead to the inefficacy of control attempts and, simultaneously, make this species able to repopulate sites previously treated with biocides. For this reason, studies that aim at verifying the effect of molluscicides on the reproduction, growth and survival of molluscs are greatly required. Molluscicides of plant origin may represent a safe and effective way of controlling these animals. Thymol is a substance of plant origin which has bactericidal, fungicidal and anti-inflammatory properties and has been presented as a promissory biocide of mollusc species. The aim of this work was to assess the molluscicidal property of thymol in combination with DMSO against eggs and adults of B. similaris. During 120 days, we evaluated the effect of thymol+DMSO at different concentrations (2.5 g/L and 5 g/L on the hatching success, hatchling survival, growth and reproduction of B. similaris under laboratory

  3. Growth and reproduction respond differently to climate in three Neotropical tree species.

    Science.gov (United States)

    Alfaro-Sánchez, Raquel; Muller-Landau, Helene C; Wright, S Joseph; Camarero, J Julio

    2017-06-01

    The response of tropical forests to anthropogenic climate change is critically important to future global carbon budgets, yet remains highly uncertain. Here, we investigate how precipitation, temperature, solar radiation and dry- and wet-season lengths are related to annual tree growth, flower production, and fruit production in three moist tropical forest tree species using long-term datasets from tree rings and litter traps in central Panama. We also evaluated how growth, flower, and fruit production were interrelated. We found that growth was positively correlated with wet-season precipitation in all three species: Jacaranda copaia (r = 0.63), Tetragastris panamensis (r = 0.39) and Trichilia tuberculata (r = 0.39). Flowering and fruiting in Jacaranda were negatively related to current-year dry-season rainfall and positively related to prior-year dry-season rainfall. Flowering in Tetragastris was negatively related to current-year annual mean temperature while Trichilia showed no significant relationships of reproduction with climate. Growth was significantly related to reproduction only in Tetragastris, where it was positively related to previous year fruiting. Our results suggest that tree growth in moist tropical forest tree species is generally reduced by drought events such as those associated with strong El Niño events. In contrast, interannual variation in reproduction is not generally associated with growth and has distinct and species-specific climate responses, with positive effects of El Niño events in some species. Understanding these contrasting climate effects on tree growth and reproduction is critical to predicting changes in tropical forest dynamics and species composition under climate change.

  4. Dynamic Urban Growth Models

    Science.gov (United States)

    1979-12-01

    In the report the concept of 'order by fluctuation,' that has appeared recently in physico-chemical and biological systems, is applied to the description of urban growth. It is shown that fluctuations play a vital role in the evolutionary process of ...

  5. Growth and reproductive performance by different feed types in fresh water angelfish (Pterophyllum scalare Schultze, 1823

    Directory of Open Access Journals (Sweden)

    Milad Kasiri

    2012-09-01

    Full Text Available It is well established that reproduction is sensitive to the state of energy reserves, and that there is a balance between energy homeostasis and fertility. In this view, this study examined the effects of different diets on growth and reproductive performance of fresh water angelfish. Twenty four pairs of angelfish (weighing 3.58 ± 0.24 g were fed with four types of diets including live earth worm (LEW, dried Tubifex (DT, dried Gammarus (DG and prepared granulated feed (PGF, twice a day for 90 days. Reproductive parameters were measured between days 60 and 90. The significant increase in the gonadosomatic index (GSI, fecundity and hatchability brought about by the LEW were demonstrated by the higher number of spawned eggs and hatched larvae. The best growth observed significantly in PGF, and length of larvae was enhanced in this group, consequently. The numbers of dead and deformed fry were lower in the fish fed with PGF and LEW, but there was no significant difference among experimental groups. This study showed that breeders benefit from inclusion of prepared granulated feed and living earth worm during their growth and reproductive stages, and simultaneous using of them for achieving better results is suggested.

  6. Influences of Temperature on Development and Survival, Reproduction and Growth of a Calanoid Copepod (Pseudodiaptomus dubia

    Directory of Open Access Journals (Sweden)

    Changling Li

    2009-01-01

    Full Text Available Pseudodiaptomus dubia is a calanoid copepod that is distributed widely in the estuarine-coastal waters of Asia and is a dominant copepod in the shrimp grow-out ponds in southern China. A laboratory culture experiment was conducted to evaluate the influences of water temperature on larval development, survival, and reproduction. Results indicate that within a temperature range from 15 to 35°C, larval development increases as the temperature increases. The water temperature for optimal larval survival rate ranges from 20 to 35°C. Longevity and egg hatching time decrease as the temperature increases from 20 to 35°C. Total fecundity and reproduction frequency increase as the water temperature increases, with the maximum at 30°C. Fecundity and reproduction frequency decrease when the temperature exceeds 30°C. Intrinsic growth rate (rm ranges from 0.168 to 0.195 at 25 to 30°C; net reproduction rate (R0 and finite growth rate (? are 163 to 264 and 1.183 to 1.215, respectively, when the temperature is greater than 20 and 35°C; population doubling time (t varies from 3.556 to 4.128 days at temperatures less than 20 and 35°C. Population generation time (T is negatively correlated with temperature, with the optimal population growth rate at 25 to 30°C.

  7. Influence of copper on the feeding rate, growth and reproduction of the golden apple snail, Pomacea canaliculata Lamarck.

    Science.gov (United States)

    Peña, Silvia C; Pocsidio, Glorina N

    2007-12-01

    The influence of copper on feeding rate, growth, and reproduction of Pomacea canaliculata Lamarck was evaluated. Ten days of exposure to copper of relatively high concentration (67.5 microg/L) reduced the snails' feeding rate and retarded their growth. Exposure to 20 microg/L after 36 days increased feeding rate to 28%. After 20 days of exposure at 30 microg/L, snail's growth was significant but thereafter declined. Growth of all snails including control was negligible by day 50 when snails were in the reproductive state. Copper did not affect reproduction.

  8. Recent female mouse models displaying advanced reproductive aging.

    Science.gov (United States)

    Danilovich, Natalia; Ram Sairam, M

    2006-02-01

    Reproductive senescence occurs in all female mammals with resultant changes in numerous body functional systems and several important features may be species-specific. Those features that appear to parallel human menopause and aging include general similarity of hormone profiles across the menopausal transition, progression to cycle termination through irregular cycles, declining fertility with age, disturbances in thermogenesis, age-related gains in body weight, fat distribution and disposition towards metabolic syndrome. Structural and hormonal changes in the brain and ovary play a critical role in determining the onset of reproductive senescence. The short life span of rodents such as mice (compared to humans) and the ability to generate specific and timed gene deletions, provide powerful experimental paradigms to understand the molecular and functional changes that precede and follow the loss of reproductive capacity. In theory, any manipulation that compromises ovarian function either partly or totally would impact reproductive events at various levels followed by other dysfunctions. In this article, we provide an overview of three mouse models for the study of female reproductive aging. They are derived from different strategies and their age related phenotypes have been characterized to varying degrees. The follitropin receptor knockout (FORKO) mouse, in its null and haploinsufficient state as well as the dioxin/aryl hydrocarbon receptor (AhR) knockout mouse, serve as two examples of single gene deletions. A third model, using administration of a chemical toxicant such as 4-vinylcyclohexene diepoxide (VCD) in the adult state, produces ovarian deficiencies accompanied by aging changes. These will serve as useful alternatives to previously used radical ovariectomy in young adults. It is anticipated that these new models and more that will be forthcoming will extend opportunities to understand reproductive aging and resolve controversies that abound on issues

  9. Effects of Pesticides on the Growth and Reproduction of Earthworm: A Review

    Directory of Open Access Journals (Sweden)

    Shahla Yasmin

    2010-01-01

    Full Text Available Scientific literature addressing the influence of pesticides on the growth and reproduction of earthworm is reviewed. Earthworms are considered as important bioindicators of chemical toxicity in the soil ecosystem. Studies on this aspect are important because earthworms are the common prey of many terrestrial vertebrate species such as birds and small mammals, and thus they play a key role in the biomagnification process of several soil pollutants. Majority of the studies have used mortality as an endpoint rather than subtler endpoints such as reproductive output. It is now emphasized that, whereas higher concentrations of a pollutant can easily be assessed with the acute (mortality test, contaminated soils with lower (sublethal pollutant concentrations require more sensitive test methods such as reproduction test in their risk assessment.

  10. Effects of Pesticides on the Growth and Reproduction of Earthworm: A Review

    International Nuclear Information System (INIS)

    Yasmin, S.; Doris D'Souza, D.

    2010-01-01

    Scientific literature addressing the influence of pesticides on the growth and reproduction of earthworm is reviewed. Earthworms are considered as important bio indicators of chemical toxicity in the soil ecosystem. Studies on this aspect are important because earthworms are the common prey of many terrestrial vertebrate species such as birds and small mammals, and thus they play a key role in the bio magnification process of several soil pollutants. Majority of the studies have used mortality as an endpoint rather than subtler endpoints such as reproductive output. It is now emphasized that, whereas higher concentrations of a pollutant can easily be assessed with the acute (mortality) test, contaminated soils with lower (sublethal) pollutant concentrations require more sensitive test methods such as reproduction test in their risk assessment.

  11. Studies on the growth and reproduction of cattle in the tropics

    International Nuclear Information System (INIS)

    Frisch, J.E.

    1990-01-01

    The results of a number of studies that had the long term aim of increasing the productivity of cattle in the tropics are reported. The studies were conducted on the B (Brahman), HS (interbred Hereford x Shorthorn), F 1 BX (first cross B x HS) and F n BX (interbred B x HS) lines. These breeds were used to demonstrate the origins of the heterosis that occurs in both the realized growth and the reproductive rate of Bos indicus x Bos taurus. Genetic and environmental factors that limit the realized reproductive rates were also investigated. The reproductive rate of cows of each breed that differed in lactation status during the breeding season was compared in contrasting environments. It was shown that the main limitation to HS achieving high realized reproductive rates was of environmental origin. For B cows, the main limitation was associated with the stress of lactation. Unsuccessful attempts were made to overcome this limitation by using progesterone releasing intravaginal devices alone or in combination with temporary calf weaning to try to induce a fertile oestrus. Improvement of the realized reproductive rates in the HS line was achieved by increasing their resistance to environmental stresses. The prospects for increasing the realized reproductive rate of maiden heifers by increasing their live weight at the start of their first breeding season were also investigated. About half of the heifers of each breed were implanted with the synthetic growth promotant Synovex 'H' on three occasions before the start of the breeding season. Although the live weight of all breeds increased in response to Synovex 'H', the magnitude of the response was dependent on the presence or absence of parasite control. Previously implanted heifers had a lower pregnancy rate than non-implanted heifers. 4 refs, 6 tabs

  12. Silicon improves rice grain yield and photosynthesis specifically when supplied during the reproductive growth stage.

    Science.gov (United States)

    Lavinsky, Alyne O; Detmann, Kelly C; Reis, Josimar V; Ávila, Rodrigo T; Sanglard, Matheus L; Pereira, Lucas F; Sanglard, Lílian M V P; Rodrigues, Fabrício A; Araújo, Wagner L; DaMatta, Fábio M

    2016-11-01

    Silicon (Si) has been recognized as a beneficial element to improve rice (Oryza sativa L.) grain yield. Despite some evidence suggesting that this positive effect is observed when Si is supplied along the reproductive growth stage (from panicle initiation to heading), it remains unclear whether its supplementation during distinct growth phases can differentially impact physiological aspects of rice and its yield and the underlying mechanisms. Here, we investigated the effects of additions/removals of Si at different growth stages and their impacts on rice yield components, photosynthetic performance, and expression of genes (Lsi1, Lsi2 and Lsi6) involved in Si distribution within rice shoots. Positive effects of Si on rice production and photosynthesis were manifested when it was specifically supplied during the reproductive growth stage, as demonstrated by: (1) a high crop yield associated with higher grain number and higher 1000-grain weight, whereas the leaf area and whole-plant biomass remained unchanged; (2) an increased sink strength which, in turn, exerted a feed-forward effect on photosynthesis that was coupled with increases in both stomatal conductance and biochemical capacity to fix CO 2 ; (3) higher Si amounts in the developing panicles (and grain husks) in good agreement with a remarkable up-regulation of Lsi6 (and to a lesser extent Lsi1). We suggest that proper levels of Si in these reproductive structures seem to play an as yet unidentified role culminating with higher grain number and size. Copyright © 2016 Elsevier GmbH. All rights reserved.

  13. Effects of light quality on reproduction, growth and pigment content of Gracilaria birdiae (Rhodophyta: Gracilariales

    Directory of Open Access Journals (Sweden)

    José Bonomi Barufi

    2015-03-01

    Full Text Available Gracilaria species are the main source of agar worldwide. Since laboratory cultivation is an important means of sustaining such production, this study aimed to assess the influence of two fundamental strategies of physiological algae adjustment, photoacclimation and photomorphogenesis, on G. birdiae physiology. Specifically, the effects of different spectral light qualities on reproduction, growth, and pigment content in two distinct photoperiods (8 and 14 hours were examined. Tetrasporophytes and gametophytes were submitted to different light qualities: white, green, red, and blue over the course of nine weeks. At the end of this period, chlorophyll a, allophycocyanin, phycocyanin, and phycoerythrin contents were analysed. Gametophytes showed reproductive structures only under monochromatic radiation. A stimulatory effect on tetrasporangium differentiation was mainly observed under red light, but this high fertility was negatively correlated with growth rate, i.e. algae cultivated under red light showed the lowest growth rate. However, while growth rates were higher in algae exposed to white light, they were similar to those observed in algae subjected to green light and 14 hours of daylight. PE was the predominant pigment, irrespective of light quality. Phycocyanin and phycoerythrin concentration increased when algae were cultivated under green and blue light. Therefore, considering future management prospects for G. birdiae mariculture, we suggest that red light could be utilized as a reproductive inductor to produce tetraspores. Furthermore, if the aim is to achieve high phycoerythrin content, continuous blue light could be applied during a short photoperiod. Indeed, the combination of different wavelengths could allow better economic resource exploitation.

  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. 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.

  16. Effects of Elevated Ambient Temperature on Reproductive Outcomes and Offspring Growth Depend on Exposure Time

    Directory of Open Access Journals (Sweden)

    Huda Yahia Hamid

    2012-01-01

    Full Text Available Reproductive performance has been shown to be greatly affected by changes in environmental factors, such as temperature. However, it is also crucial to identify the particular stage of pregnancy that is most adversely affected by elevated ambient temperature. The aims of this study were to determine the effect on reproductive outcomes of exposure to elevated ambient temperature during different stages of pregnancy and to determine the effect of prenatal heat stress on offspring growth. Sixty pregnant rats were used in this study. The rats were divided equally into four groups as group 1 (control, group 2 (exposed to elevated temperature following implantation, group 3 (exposed to elevated temperature during pre- and periimplantation, and group 4 (exposed to elevated temperature during pre- and periimplantation and following implantation. Groups 3 and 4 had prolonged gestation periods, reduced litter sizes, and male-biased sex ratios. Moreover, the growth patterns of group 3 and 4 pups were adversely affected by prenatal exposure to elevated temperature. The differences between group 1 and group 3 and between group 1 and group 4 were highly significant. However, no significant differences were observed between groups 1 and 2 in the gestation length, sex ratios, and growth patterns. Thus, it can be concluded that exposure to elevated ambient temperature during pre- and periimplantation has stronger adverse effects on reproductive outcomes and offspring growth than postimplantation exposure.

  17. Toxicity of Nanoparticles on the Reproductive System in Animal Models: A Review

    Directory of Open Access Journals (Sweden)

    Rahim Dad Brohi

    2017-09-01

    Full Text Available In the last two decades, nanotechnologies demonstrated various applications in different fields, including detection, sensing, catalysis, electronics, and biomedical sciences. However, public concerns regarding the well-being of human may hinder the wide utilization of this promising innovation. Although, humans are exposed to airborne nanosized particles from an early age, exposure to such particles has risen dramatically within the last century due to anthropogenic sources of nanoparticles. The wide application of nanomaterials in industry, consumer products, and medicine has raised concerns regarding the potential toxicity of nanoparticles in humans. In this review, the effects of nanomaterials on the reproductive system in animal models are discussed. Females are particularly more vulnerable to nanoparticle toxicity, and toxicity in this population may affect reproductivity and fetal development. Moreover, various types of nanoparticles have negative impacts on male germ cells, fetal development, and the female reproductive system. These impacts are associated with nanoparticle modification, composition, concentration, route of administration, and the species of the animal. Therefore, understanding the impacts of nanoparticles on animal growth and reproduction is essential. Many studies have examined the effects of nanoparticles on primary and secondary target organs, with a concentration on the in vivo and in vitro effects of nanoparticles on the male and female reproductive systems at the clinical, cellular, and molecular levels. This review provides important information regarding organism safety and the potential hazards of nanoparticle use and supports the application of nanotechnologies by minimizing the adverse effects of nanoparticles in vulnerable populations.

  18. Toxicity of Nanoparticles on the Reproductive System in Animal Models: A Review

    Science.gov (United States)

    Brohi, Rahim Dad; Wang, Li; Talpur, Hira Sajjad; Wu, Di; Khan, Farhan Anwar; Bhattarai, Dinesh; Rehman, Zia-Ur; Farmanullah, F.; Huo, Li-Jun

    2017-01-01

    In the last two decades, nanotechnologies demonstrated various applications in different fields, including detection, sensing, catalysis, electronics, and biomedical sciences. However, public concerns regarding the well-being of human may hinder the wide utilization of this promising innovation. Although, humans are exposed to airborne nanosized particles from an early age, exposure to such particles has risen dramatically within the last century due to anthropogenic sources of nanoparticles. The wide application of nanomaterials in industry, consumer products, and medicine has raised concerns regarding the potential toxicity of nanoparticles in humans. In this review, the effects of nanomaterials on the reproductive system in animal models are discussed. Females are particularly more vulnerable to nanoparticle toxicity, and toxicity in this population may affect reproductivity and fetal development. Moreover, various types of nanoparticles have negative impacts on male germ cells, fetal development, and the female reproductive system. These impacts are associated with nanoparticle modification, composition, concentration, route of administration, and the species of the animal. Therefore, understanding the impacts of nanoparticles on animal growth and reproduction is essential. Many studies have examined the effects of nanoparticles on primary and secondary target organs, with a concentration on the in vivo and in vitro effects of nanoparticles on the male and female reproductive systems at the clinical, cellular, and molecular levels. This review provides important information regarding organism safety and the potential hazards of nanoparticle use and supports the application of nanotechnologies by minimizing the adverse effects of nanoparticles in vulnerable populations. PMID:28928662

  19. Effects of the fungicide copper oxychloride on the growth and reproduction of Eisenia fetida (Oligochaeta).

    Science.gov (United States)

    Helling, B; Reinecke, S A; Reinecke, A J

    2000-05-01

    The article describes a laboratory experiment to determine the effect of copper oxychloride on the earthworm Eisenia fetida. Copper oxychloride was used because it is the most commonly used fungicide in South African vineyards but not much is known about its toxicity to earthworms. In an experiment lasting 8 weeks, newly hatched earthworms of the species E. fetida were exposed to copper oxychloride mixed into a urine-free cattle manure substrate. Four groups of 10 worms were used per concentration level (control (4.02), 8.92, 15.92, 39.47, 108.72, 346.85 mg Cu kg substrate(-1)). The following life-history parameters were measured: earthworm growth in consecutive weeks, survival rate, maturation time, cocoon production, reproduction success, total number of hatchlings produced, and incubation time. Earthworm growth and cocoon production were significantly reduced at copper oxychloride exposure concentrations of 8.92 mg kg(-1) and higher. Reproduction success in the 8.92 mg Cu kg substrate(-1) was highest. From an exposure concentration of 15. 92 mg Cu kg substrate(-1) and higher, there was a considerable impact of copper oxychloride on reproduction. This could be seen from a reduced reproduction success, a reduced mean and maximum number of hatchlings per cocoon, and a longer incubation time, indicating a strong effect of low copper oxychloride concentrations on this earthworm species. Copyright 2000 Academic Press.

  20. Growth and reproductive investment of introduced Pacific oysters Crassostrea gigas in southern European waters

    Science.gov (United States)

    Cardoso, Joana F. M. F.; Peralta, Nelson R. E.; Machado, Jorge P.; van der Veer, Henk W.

    2013-02-01

    Growth and reproductive investment of cultured Pacific oysters Crassostrea gigas were studied in two south-western European estuaries: the Ría de Ribadeo in Spain and the Ria Formosa in Portugal. Developing gonads were found in individuals >23.5 mm shell length in the Ria Formosa and >27.5 mm shell length in the Ría de Ribadeo. Although the amount of gonadal mass in relation to total body mass was higher in the Ría de Ribadeo, oysters from this location did not spawn completely. In contrast, oysters from the Ria Formosa completely emptied their gonad during spawning. Reproduction and, consequently, the maximum potential for population expansion may be constrained in both areas: in the Ría de Ribadeo due to suboptimal spawning threshold temperatures and in the Ria Formosa due to higher metabolic costs caused by warmer winter temperatures. Nevertheless, in comparison to northern oyster populations, Portuguese and Spanish populations have higher reproductive output. If suitable environmental conditions are met, expansion of Portuguese and Spanish populations will most likely occur. In the Ria Formosa, where environmental conditions for growth and reproduction are favourable, wild oysters are already observed. In order to follow the dynamics of oyster populations and predict possible negative effects on the ecosystems, it is important to continue monitoring the physiological performance of C. gigas in these areas.

  1. Towards greater realism in inclusive fitness models: the case of worker reproduction in insect societies.

    Science.gov (United States)

    Wenseleers, Tom; Helanterä, Heikki; Alves, Denise A; Dueñez-Guzmán, Edgar; Pamilo, Pekka

    2013-01-01

    The conflicts over sex allocation and male production in insect societies have long served as an important test bed for Hamilton's theory of inclusive fitness, but have for the most part been considered separately. Here, we develop new coevolutionary models to examine the interaction between these two conflicts and demonstrate that sex ratio and colony productivity costs of worker reproduction can lead to vastly different outcomes even in species that show no variation in their relatedness structure. Empirical data on worker-produced males in eight species of Melipona bees support the predictions from a model that takes into account the demographic details of colony growth and reproduction. Overall, these models contribute significantly to explaining behavioural variation that previous theories could not account for.

  2. Temperature modulates dengue virus epidemic growth rates through its effects on reproduction numbers and generation intervals.

    Science.gov (United States)

    Siraj, A. S.; Oidtman, R. J.; Huber, J. H.; Kraemer, M. U.; Brady, O. J.; Johansson, M. A.; Perkins, T. A.

    2017-12-01

    Epidemic growth rate, r, provides a more complete description of the potential for epidemics than the more commonly studied basic reproduction number, R0, yet the former has never been described as a function of temperature for dengue virus or other pathogens with temperature-sensitive transmission. The need to understand the drivers of epidemics of these pathogens is acute, with arthropod-borne virus epidemics becoming increasingly problematic. We addressed this need by developing temperature-dependent descriptions of the two components of r—R0 and the generation interval—to obtain a temperature-dependent description of r. Our results show that the generation interval is highly sensitive to temperature, decreasing twofold between 25 and 35 °C and suggesting that dengue virus epidemics may accelerate as temperatures increase, not only because of more infections per generation but also because of faster generations. Under the empirical temperature relationships that we considered, we found that r peaked at a temperature threshold that was robust to uncertainty in model parameters that do not depend on temperature. Although the precise value of this temperature threshold could be refined following future studies of empirical temperature relationships, the framework we present for identifying such temperature thresholds offers a new way to classify regions in which dengue virus epidemic intensity could either increase or decrease under future climate change.

  3. Androgen Receptors Expression in Pituitary of Male Viscacha in relation to Growth and Reproductive Cycle

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    Verónica Palmira Filippa

    2015-01-01

    Full Text Available The aim of this work was to study the androgen receptors (AR expression in pituitary pars distalis (PD of male viscachas in relation to growth and reproductive cycle. AR were detected by immunocytochemistry and quantified by image analysis. Pituitary glands from fetus, immature, prepubertal, and adult viscachas during their reproductive cycle were used. In the fetal PD, the immunoreactivity (ir was mainly cytoplasmic. In immature and prepubertal animals, AR-ir was cytoplasmic (ARc-ir and nuclear (ARn-ir in medial region. In adult animals, ARn-ir cells were numerous at caudal end. AR regionalization varied between the PD zones in relation to growth. In immature animals, the ARn-ir increased whereas the cytoplasmic expression decreased in relation to the fetal glands. The percentage of ARc-ir cells increased in prepubertal animals whereas the nuclear AR expression was predominant in adult viscachas. The AR expression changed in adults, showing minimum percentage in the gonadal regression period. The variation of nuclear AR expression was directly related with testosterone concentration. These results demonstrated variations in the immunostaining pattern, regionalization, and number of AR-ir cells throughout development, growth, and reproductive cycle, suggesting the involvement of AR in the regulation of the pituitary activity of male viscacha.

  4. Age, Growth and Reproduction of Coryphaena hippurus (Linnaeus, 1758 in Maltese Waters, Central Mediterranean

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    M. GATT

    2015-04-01

    Full Text Available Age, growth and reproduction of the dolphinfish Coryphaena hippurus Linnaeus, 1758 collected from the Central Mediterranean in the period 2004-2010 by the traditional Maltese fish aggregating devices (FAD and surface longline fisheries were studied. The a and b parameters of the length-weight relationship for fish 11-142 cm fork length (FL (n = 4042 were determined as a = 0.018 and 0.022 with b = 2.85 and 2.79, for males and females respectively. The counting of annual increments from dorsal spines of >65 cm FL dolphinfish at X25 magnification (n = 47 permitting an age reading resolution in years  , and the counting of daily increments from sagittal otoliths of <65 cm FL dolphinfish at X400 magnification (n = 583 permitting an age reading resolution in days, were estimated; the von Bertalanffy growth model applied to these fish gave the following parameters: L∞ = 107.8 cm FL and 120.2 cm FL, and K = 1.9 yr-1 and 1.56 yr-1, for males and females respectively. The maximum age observed was 2 years. Size at 50% maturity for fish 10-131 cm FL (n = 1376 was 58.9 cm FL and 62.5 cm FL for males and females, respectively. The sex ratio for the fish sampled from the FAD fishery (10.5-131 cm FL was 1:1.54 (M:F and for dolphinfish sampled from the surface longline fishery (91-130 cm FL was 1:0.76 (M:F.  Back-calculated hatch dates from age-0 dolphinfish (n = 518 suggested that spawning occurs from June to September with the highest levels in June. This study is the first to use dorsal spines to determine the age of adult dolphinfish.

  5. Model uncertainty in growth empirics

    NARCIS (Netherlands)

    Prüfer, P.

    2008-01-01

    This thesis applies so-called Bayesian model averaging (BMA) to three different economic questions substantially exposed to model uncertainty. Chapter 2 addresses a major issue of modern development economics: the analysis of the determinants of pro-poor growth (PPG), which seeks to combine high

  6. Impacts of breeder loss on social structure, reproduction and population growth in a social canid.

    Science.gov (United States)

    Borg, Bridget L; Brainerd, Scott M; Meier, Thomas J; Prugh, Laura R

    2015-01-01

    The importance of individuals to the dynamics of populations may depend on reproductive status, especially for species with complex social structure. Loss of reproductive individuals in socially complex species could disproportionately affect population dynamics by destabilizing social structure and reducing population growth. Alternatively, compensatory mechanisms such as rapid replacement of breeders may result in little disruption. The impact of breeder loss on the population dynamics of social species remains poorly understood. We evaluated the effect of breeder loss on social stability, recruitment and population growth of grey wolves (Canis lupus) in Denali National Park and Preserve, Alaska using a 26-year dataset of 387 radiocollared wolves. Harvest of breeding wolves is a highly contentious conservation and management issue worldwide, with unknown population-level consequences. Breeder loss preceded 77% of cases (n = 53) of pack dissolution from 1986 to 2012. Packs were more likely to dissolve if a female or both breeders were lost and pack size was small. Harvest of breeders increased the probability of pack dissolution, likely because the timing of harvest coincided with the breeding season of wolves. Rates of denning and successful recruitment were uniformly high for packs that did not experience breeder loss; however, packs that lost breeders exhibited lower denning and recruitment rates. Breeder mortality and pack dissolution had no significant effects on immediate or longer term population dynamics. Our results indicate the importance of breeding individuals is context dependent. The impact of breeder loss on social group persistence, reproduction and population growth may be greatest when average group sizes are small and mortality occurs during the breeding season. This study highlights the importance of reproductive individuals in maintaining group cohesion in social species, but at the population level socially complex species may be resilient

  7. Use of learning models and media regarding reproductive health attitudes and reproductive system learning outcomes in senior high schools

    Directory of Open Access Journals (Sweden)

    Isoh Sukaesah, Rusdi

    2017-12-01

    Full Text Available Model and learning media is an important component that may affect the achievement of learning objectives. Model selection and appropriate learning media can improve student learning outcomes both in the cognitive and affective domains. This study was aimed to examine the effect of the learning model Think Pair Share (TPS, Student Team Achievement Division (STAD and Conventional learning model and the interaction model and learning media attitude towards reproductive health and student learning outcomes in the material reproductive system. The study was conducted at XI MIA grade students in four Senior High Schools in North Jakarta the academic year 2014/2015. Data were collected through the test instrument scale reproductive health attitudes and learning outcomes instruments reproductive system. Data were analyzed by Two-Way ANOVA and Tukey Test. The results showed that the use of models and instructional media and the interaction between the model and learning media significantly influence the attitude of reproductive health and learning outcomes of the reproductive system of high school students with a significance value (p<  = 0.01.

  8. Cyclic variations in nitrogen uptake rate in soybean plants: uptake during reproductive growth.

    Science.gov (United States)

    Vessey, J K; Raper, C D; Henry, L T

    1990-12-01

    Net uptake of NO3- by non-nodulated soybean plants [Glycine max (L.) Merr. cv. Ransom] growing in flowing hydroponic culture was measured daily during a 63 d period of reproductive development between the first florally inductive photoperiod and [unknown word] seed growth. Removal of NO3- from a replenished solution containing 1.0 mol m-3 NO3- was determined by ion chromatography. Uptake of NO3- continued throughout reproductive development. The net uptake rate of NO3- cycled between maxima and minima with a periodicity of oscillation of 3 to 7 d during the floral stage and about 6 d during the fruiting stage. Coupled with increasing concentrations of carbon and C : N ratios in tissues, the oscillations in net uptake rates of NO3- are evidence that the demand for carbohydrate by reproductive organs is contingent on the availability of nitrogen in the shoot pool rather than that the demand for nitrogen follows the flux of carbohydrate into reproductive tissues.

  9. Cyclic variations in nitrogen uptake rate in soybean plants: uptake during reproductive growth

    Science.gov (United States)

    Vessey, J. K.; Raper, C. D. Jr; Henry, L. T.; Raper CD, J. r. (Principal Investigator)

    1990-01-01

    Net uptake of NO3- by non-nodulated soybean plants [Glycine max (L.) Merr. cv. Ransom] growing in flowing hydroponic culture was measured daily during a 63 d period of reproductive development between the first florally inductive photoperiod and [unknown word] seed growth. Removal of NO3- from a replenished solution containing 1.0 mol m-3 NO3- was determined by ion chromatography. Uptake of NO3- continued throughout reproductive development. The net uptake rate of NO3- cycled between maxima and minima with a periodicity of oscillation of 3 to 7 d during the floral stage and about 6 d during the fruiting stage. Coupled with increasing concentrations of carbon and C : N ratios in tissues, the oscillations in net uptake rates of NO3- are evidence that the demand for carbohydrate by reproductive organs is contingent on the availability of nitrogen in the shoot pool rather than that the demand for nitrogen follows the flux of carbohydrate into reproductive tissues.

  10. Effects of melatonin implantation on cashmere yield, fibre characteristics, duration of cashmere growth as well as growth and reproductive performance of Inner Mongolian cashmere goats

    OpenAIRE

    Duan, Chunhui; Xu, Jianhai; Sun, Changmian; Jia, Zhihai; Zhang, Wei

    2015-01-01

    Background Exogenous melatonin could induce cashmere growth. However, induced growth of cashmere fleece by melatonin implants cannot be combined with the typical growth, resulting in earlier shedding followed by another cycle of cashmere growth. To address this issue, we examine the effects on the cashmere yield, fibre characteristics, and the growth and reproductive performance of cashmere goats of planned administration of melatonin. Methods Eighteen half-sib, female goats were assigned to ...

  11. Acute and chronic toxicity of polychlorinated biphenyl 126 to Tigriopus japonicus: effects on survival, growth, reproduction, and intrinsic rate of population growth.

    Science.gov (United States)

    Guo, Feng; Wang, Lei; Wang, Wen-Xiong

    2012-03-01

    The harpacticoid copepod Tigriopus japonicus has a wide geographical distribution and is considered as a suitable model species for the assessment of toxicity of marine pollutants. The aim of the present study was to test the impacts of polychlorinated biphenyl (PCB) 126 (3,3',4,4',5-pentachlorobiphenyl) on the growth, development, and reproduction of T. japonicus in two successive generations. We first quantified the 96-h 50% lethal concentration (2.83 mg/L; all reported concentrations are nominal values), the no-observed-effect concentration (0.6 mg/L), and the lowest-observed-effect concentration (LOEC; 1.2 mg/L) of PCB126 in the nauplii. Nauplii were more sensitive than the adults, which still survived at the highest tested PCB126 concentration (8 mg/L). In the chronic toxicity testing, 10 life history traits were quantified for T. japonicus. No obvious effect on any of these traits was observed in the first generation (F0) at tested concentrations (life-cycle exposure (F1), however, PCB126 had an obvious toxic effect on the reproduction (>1 µg/L) and growth (>0.1 µg/L). Thus, copepods became more sensitive to PCB126 exposure as generations developed. Among the different traits tested, body size was the most sensitive parameter. Reproduction (fecundity, number of clutches, nauplii/clutch) and intrinsic population growth were also significantly impacted by PCB exposure. The survivorship, sex ratio, hatching time, and development were not affected. Environmental risk assessment of contaminants must therefore be based on a long-term multigenerational exposure to provide a realistic measurement of the influences of pollutants on aquatic life. Copyright © 2011 SETAC.

  12. Survival, growth and reproduction of cryopreserved larvae from a marine invertebrate, the Pacific oyster (Crassostrea gigas.

    Directory of Open Access Journals (Sweden)

    Marc Suquet

    Full Text Available This study is the first demonstration of successful post-thawing development to reproduction stage of diploid cryopreserved larvae in an aquatic invertebrate. Survival, growth and reproductive performances were studied in juvenile and adult Pacific oysters grown from cryopreserved embryos. Cryopreservation was performed at three early stages: trochophore (13±2 hours post fertilization: hpf, early D-larvae (24±2 hpf and late D-larvae (43±2 hpf. From the beginning (88 days at the end of the ongrowing phase (195 days, no mortality was recorded and mean body weights did not differ between the thawed oysters and the control. At the end of the growing-out phase (982 days, survival of the oysters cryopreserved at 13±2 hpf and at 43±2 hpf was significantly higher (P<0.001 than those of the control (non cryopreserved larvae. Only the batches cryopreserved at 24±2 hpf showed lower survival than the control. Reproductive integrity of the mature oysters, formely cryopreserved at 13±2 hpf and 24±2 hpf, was estimated by the sperm movement and the larval development of their offspring in 13 crosses gamete pools (five males and five females in each pool. In all but two crosses out of 13 tested (P<0.001, development rates of the offspring were not significantly different between frozen and unfrozen parents. In all, the growth and reproductive performances of oysters formerly cryopreserved at larval stages are close to those of controls. Furthermore, these performances did not differ between the three initial larval stages of cryopreservation. The utility of larvae cryopreservation is discussed and compared with the cryopreservation of gametes as a technique for selection programs and shellfish cryobanking.

  13. Inoculum levels of Meloidogyne hispanica and M. javanica affect nematode reproduction, and growth of tomato genotypes

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    Carla M.N. MALEITA

    2013-01-01

    Full Text Available A pot experiment was conducted to determine the effects of three inoculum levels (2,500, 5,000 and 10,000 eggs/plant on the reproduction of Meloidogyne hispanica and M. javanica isolates and growth of the susceptible tomato genotypes Easypeel and Moneymaker, and genotypes Motelle and VFnt-Cherr, which possess the Mi-gene, at 25±2°C. sixty days after inoculation, roots were assessed for gall index (Gi, reproduction factor (Rf=final/initial population density and reproduction index (RI=Rf in the Mi-gene tomato plants/Rf in tomato Easypeel × 100. shoot and root lengths and fresh and dry root and shoot weights were also recorded. both species of Meloidogyne reproduced at all inoculum levels on all four tomato genotypes (4≤GI≤5 and 3.44≤Rf≤317.30. The M. javanica isolate, obtained from an infected potato field, was identified as natural and partially virulent to the Mi-gene (3.71≤RI≤20.19. This emphasizes the need for new sources of resistance to root-knot nematodes and for testing Mi-tomato plants for their susceptibility to local populations. Reproduction of M. javanica and M. hispanica on the resistant Motelle and VFNT-Cherr was significantly less than on the susceptible Easypeel and Moneymaker. VFNT-Cherr was more resistant than Motelle, which suggest an influence of the genetic background of the plants on the nematode response. For Easypeel and Moneymaker, there was a trend of decreased plant growth parameters with increasing inoculum level, irrespective of the nematode species, due to damage caused by the increasing number of nematodes that invaded plant roots. However, these values on Motelle and VFnt-Cherr remained relatively stable regarding shoot and total shoot plus root dry weight. the reproductive rate of M. javanica was greater than that of M. hispanica on all four genotypes tested, and tomato plants inoculated with M. hispanica had greater growth parameters. the resistance response of the Mi-tomato plants was independent

  14. No evidence for a critical salinity threshold for growth and reproduction in the freshwater snail Physa acuta

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J. [Biotechnology and Environmental Biology, School of Applied Science, RMIT University, PO Box 71, Bundoora 3083, Vic (Australia)]. E-mail: ben.kefford@rmit.edu.au; Nugegoda, Dayanthi [Biotechnology and Environmental Biology, School of Applied Science, RMIT University, PO Box 71, Bundoora 3083, Vic (Australia)

    2005-04-01

    The growth and reproduction of the freshwater snail Physa acuta (Gastropoda: Physidae) were measured at various salinity levels (growth: distilled water, 50, 100, 500, 1000 and 5000 {mu}S/cm; reproduction: deionized water, 100, 500, 1000 and 3000 {mu}S/cm) established using the artificial sea salt, Ocean Nature. This was done to examine the assumption that there is no direct effect of salinity on freshwater animals until a threshold, beyond which sub-lethal effects, such as reduction in growth and reproduction, will occur. Growth of P. acuta was maximal in terms of live and dry mass at salinity levels 500-1000 {mu}S/cm. The number of eggs produced per snail per day was maximal between 100 and 1000 {mu}S/cm. Results show that rather than a threshold response to salinity, small rises in salinity (from low levels) can produce increased growth and reproduction until a maximum is reached. Beyond this salinity, further increases result in a decrease in growth and reproduction. Studies on the growth of freshwater invertebrates and fish have generally shown a similar lack of a threshold response. The implications for assessing the effects of salinisation on freshwater organisms need to be further considered. - Responses of snails to increasing salinity were non-linear.

  15. Growth and reproduction of the gilthead seabream Sparus aurata in Mellah lagoon (north-eastern Algeria

    Directory of Open Access Journals (Sweden)

    Lamya Chaoui

    2006-09-01

    Full Text Available Gilthead seabream Sparus aurata (L., a protandrous hermaphrodite, was caught in Mellah lagoon (Algeria from July 1997 to June 1998. Its age, growth and reproduction were studied. Fish ranged in size from 157 to 610 mm total length and weighed from 60 to 4000 g wet weight. There were fish aged 1+ to 7+ years old in the samples. Direct scale readings were made by counting the number of rings. These were compared with the data obtained by backcalculating the lengths at different ages. These two methods were in agreement and showed that the growth rate of gilthead seabream in Mellah lagoon is very high compared to other study areas. The growth parameters of the Von Bertalanffy equation were: L∞ = 55.33 cm, K = 0.513, t0 = - 0.282, with F’ = 7.359. The fitted length-weight relationship was W = 1.292. 10-2 L3.06. The reproductive season extended from October to January, with a peak in December. Sex inversion occurred at a total length of 44 cm. Sexual maturity was reached at 32.6 cm total length.

  16. Morphometry, growth and reproduction of an Atlantic population of the razor clam Ensis macha (Molina, 1782

    Directory of Open Access Journals (Sweden)

    Pedro J. Barón

    2004-06-01

    Full Text Available Ensis macha is a razor clam distributed throughout the coasts of southern Argentina and Chile. Even though it represents a valuable fishery resource, the exploitation of its Atlantic populations has begun only in recent years. This study provides the first estimates of growth rate, an interpretation of the reproductive cycle on the coast of the northern Argentine Patagonia and an analysis of the species morphometry. Growth was estimated by direct observation of growth rings on the valves by two observers. The reproductive cycle was interpreted by the analysis of temporal change of oocyte size frequency distributions. Parameter estimations for the von Bertalanffy equations respectively obtained by observers 1 and 2 were 154 and 153.7 mm for L?, 0.25 and 0.20 yr-1 for k, and -0.08 and -0.72 yr for t0. Two spawning peaks were detected: September-November 1999 and May-June 2000. However, mature females were found all year round. An abrupt change in the relationship between shell length and height was detected at 11.2 mm length.

  17. Effect of Lignite Fly Ash on the Growth and Reproduction of Earthworm Eisenia fetida

    Directory of Open Access Journals (Sweden)

    S. Sarojini

    2009-01-01

    Full Text Available Fly ash is an amorphous ferroalumino silicate, an important solid waste around thermal power plants. It creates problems leading to environmental degradation due to improper utilization or disposal. However, fly ash is a useful ameliorant that may improve the physical, chemical and biological properties of soils and is a source of readily available plant macro and micronutrients when it is used with biosolids. Supply of nutrients from fly ash with biosolids may enhance their agricultural use. The growth and reproduction of Eisenia fetida was studied during vermicomposting of fly ash with cowdung and pressmud in four different proportions (T1,T2,T3 & T4 and one control i.e., cow dung and pressmud alone. The growth, cocoon and hatchlings production were observed at the interval of 15 days over a period of 60 days. The maximum worm growth and reproduction was observed in bedding material alone. Next to that the T1 was observed as the best mixture for vermiculture.

  18. The effects of epoxiconazole and α-cypermethrin on Daphnia magna growth, reproduction, and offspring size.

    Science.gov (United States)

    Gottardi, Michele; Birch, Michala Rosa; Dalhoff, Kristoffer; Cedergreen, Nina

    2017-08-01

    Two of the main classes of pesticides commonly used in agriculture are azole fungicides and pyrethroid insecticides. Because azoles have been shown to synergize the effect of pyrethroids, the effect of their mixture is of concern. The aim of the present study was to investigate the effect of sublethal concentrations of epoxiconazole and α-cypermethrin and their mixture on growth, reproduction, and in vivo cytochrome P450 activity of the aquatic crustacean Daphnia magna over 42 d. Continuous exposure to nonlethal concentrations of α-cypermethrin at 20 ng/L negatively affected adult growth and number and size of neonates within the first 14 d of exposure. Exposure to epoxiconazole at 25 μg/L increased protein content of adults within 1 to 3 d after initiating exposure and increased cumulative number of offspring at exposure times >31 d. Epoxiconazole enhanced the negative effect of α-cypermethrin up to 3-fold leading to decreased growth, cytochrome P450 activity, and reproduction of D. magna within the first 14 d of exposure. After 14 d, the synergistic interactions disappeared. The reported effects, although lacking direct negative consequence in the long term, might have cumulative toxicity with other stressors such as food scarcity, predation, and pathogens, posing an additional hazard for the organisms at the beginning of their life cycle. Environ Toxicol Chem 2017;36:2155-2166. © 2017 SETAC. © 2017 SETAC.

  19. The application of "natural" growth rates of Heterostegina depressa to infer timing of reproduction events

    Science.gov (United States)

    Eder, Wolfgang; Julia, Woeger; Kinoshita, Shunichi; Hohenegger, Johann; Briguglio, Antonino

    2017-04-01

    To explore applicability of the natural laboratory approach (sensu Hohenegger) on population dynamic studies of recent larger benthic foraminifera, this relatively new experimental method has been applied on Heterostegina depressa populations from Sesoko Jima, NW Okinawa, Japan. It is used to gain an averaged chamber and diameter building rate, as well as the average longevity of H. depressa based on monthly samplings at fixed sampling stations. Samples were collected by SCUBA in 16 monthly intervals around 20 and 50 meters water depth, wherefrom live populations were dried and investigated by microCT. The specimens were measured regarding chamber number and maximum diameter. This biometric data has been tested for the presence of multiple generations of H. depressa megalospheres. In case of skewed or bimodal frequency distributions, they were decomposed into normally distributed components. Means and standard deviations of each component of every month were extracted and could be used to calculate the maximum values of chamber number and diameter for all sampling intervals. Based on these maximal values, the natural chamber/diameter growth rate was fitted by Michaelis-Menten functions. By inversion of this growth functions the birthdate of every specimen was calculated. Frequency diagrams of these dates reveal a continuous background reproduction throughout the year, yet show distinct reproduction peaks in late spring and late autumn. Further, sinusoidal regression analysis support these two main reproduction cycles, one short-term cycle 70 days and a one long-term cycles around 180 days. Surprisingly, similar cycles have been found in different studies on volumetric growth of larger benthic foraminifera.

  20. Thermal limits for growth and reproduction in the desert pupfish, Cyprinodon n. nevadensis

    Energy Technology Data Exchange (ETDEWEB)

    Gerking, S.D.; Lee, R.M.

    1979-01-01

    The thermal limits for growth of the desert pupfish (Cyprinodon n. nevadensis) were determined in seven-week laboratory feeding experiments at three rations (1.5, 3.0 and 4.5% body weight day) of Tetra-min prepared food and seven temperatures (12, 16, 20, 24, 28, 32, and 36 C). Curves of specific growth rates (% dry weight gain/day) as related to temperature were skewed to the left at the three rations. Growth was inhibited at 12, 16 and 36 C. Fish at the lower two temperatures were torpid and lacked appetite; the higher temperature fish did not eat sufficient food to match the high metabolic cost. The thermal scope for growth was narrowed as ration decreased and as age/size increased. Taking these factors into account, the thermal limits for growth of immature pupfish feeding at moderate to high rates were 17.5 to 31.0 C with optimum growth achieved at 22.0 C. Successful reproduction depends on egg production and egg viability.

  1. Selection for superior growth advances the onset of puberty and increases reproductive performance in ewe lambs.

    Science.gov (United States)

    Rosales Nieto, C A; Ferguson, M B; Macleay, C A; Briegel, J R; Martin, G B; Thompson, A N

    2013-06-01

    The reproductive efficiency of the entire sheep flock could be improved if ewe lambs go through puberty early and produce their first lamb at 1 year of age. The onset of puberty is linked to the attainment of critical body mass, and therefore we tested whether it would be influenced by genetic selection for growth rate or for rate of accumulation of muscle or fat. We studied 136 Merino ewe lambs with phenotypic values for depth of eye muscle (EMD) and fat (FAT) and Australian Sheep Breeding Values at post-weaning age (200 days) for live weight (PWT), eye muscle depth (PEMD) and fat depth (PFAT). First oestrus was detected with testosterone-treated wethers and then entire rams as the ewes progressed from 6 to 10 months of age. Blood concentrations of leptin and IGF-I were measured to test whether they were related to production traits and reproductive performance (puberty, fertility and reproductive rate). In total, 97% of the lambs reached first oestrus at average weight 39.4 ± 0.4 kg (mean ± s.e.m.) and age 219 days (range 163 to 301). Age at first oestrus decreased with increases in values for PWT (P ewe lambs that achieved puberty was positively related with increases in values for EMD (P ewe lambs were pregnant at average weight 44.7 ± 0.5 kg and age 263 days (range 219 to 307). Ewe lambs that were heavier at the start of mating were more fertile (P ewe lambs. The metabolic hormones, IGF-I and leptin, might act as a physiological link between the growing tissues and the reproductive axis.

  2. The effect of temperature on the photosynthesis, growth and reproduction of a Mediterranean submerged macrophyte, Ruppia drepanensis

    NARCIS (Netherlands)

    Santamaria, L.; Hootsmans, M.

    1998-01-01

    The effect of different temperatures (14, 20 and 30 degrees C) and photoperiods (10 and 16 h) on the photosynthesis, growth and reproduction of Ruppia drepanensis Tineo plants from the Donana National Park (SW Spain) were studied. After 84-91 days of growth under a 16 h photoperiod, the plants

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

    Science.gov (United States)

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

    2018-02-21

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

  4. Habitat fragmentation and reproductive success: a structural equation modelling approach.

    Science.gov (United States)

    Le Tortorec, Eric; Helle, Samuli; Käyhkö, Niina; Suorsa, Petri; Huhta, Esa; Hakkarainen, Harri

    2013-09-01

    1. There is great interest on the effects of habitat fragmentation, whereby habitat is lost and the spatial configuration of remaining habitat patches is altered, on individual breeding performance. However, we still lack consensus of how this important process affects reproductive success, and whether its effects are mainly due to reduced fecundity or nestling survival. 2. The main reason for this may be the way that habitat fragmentation has been previously modelled. Studies have treated habitat loss and altered spatial configuration as two independent processes instead of as one hierarchical and interdependent process, and therefore have not been able to consider the relative direct and indirect effects of habitat loss and altered spatial configuration. 3. We investigated how habitat (i.e. old forest) fragmentation, caused by intense forest harvesting at the territory and landscape scales, is associated with the number of fledged offspring of an area-sensitive passerine, the Eurasian treecreeper (Certhia familiaris). We used structural equation modelling (SEM) to examine the complex hierarchical associations between habitat loss and altered spatial configuration on the number of fledged offspring, by controlling for individual condition and weather conditions during incubation. 4. Against generally held expectations, treecreeper reproductive success did not show a significant association with habitat fragmentation measured at the territory scale. Instead, our analyses suggested that an increasing amount of habitat at the landscape scale caused a significant increase in nest predation rates, leading to reduced reproductive success. This effect operated directly on nest predation rates, instead of acting indirectly through altered spatial configuration. 5. Because habitat amount and configuration are inherently strongly collinear, particularly when multiple scales are considered, our study demonstrates the usefulness of a SEM approach for hierarchical partitioning

  5. Influence of plant maturity, shoot reproduction and sex on vegetative growth in the dioecious plant Urtica dioica.

    Science.gov (United States)

    Oñate, Marta; Munné-Bosch, Sergi

    2009-10-01

    Stinging nettle (Urtica dioica) is a herbaceous, dioecious perennial that is widely distributed around the world, reproduces both sexually and asexually, and is characterized by rapid growth. This work was aimed at evaluating the effects of plant maturity, shoot reproduction and sex on the growth of leaves and shoots. Growth rates of apical shoots, together with foliar levels of phytohormones (cytokinins, auxins, absicisic acid, jasmonic acid and salicylic acid) and other indicators of leaf physiology (water contents, photosynthetic pigments, alpha-tocopherol and F(v)/F(m) ratios) were measured in juvenile and mature plants, with a distinction made between reproductive and non-reproductive shoots in both males and females. Vegetative growth rates were not only evaluated in field-grown plants, but also in cuttings obtained from these plants. All measurements were performed during an active vegetative growth phase in autumn, a few months after mature plants reproduced during spring and summer. Vegetative growth rates in mature plants were drastically reduced compared with juvenile ones (48 % and 78 % for number of leaves and leaf biomass produced per day, respectively), which was associated with a loss of photosynthetic pigments (up to 24 % and 48 % for chlorophylls and carotenoids, respectively) and increases of alpha-tocopherol (up to 2.7-fold), while endogenous levels of phytohormones did not differ between mature and juvenile plants. Reductions in vegetative growth were particularly evident in reproductive shoots of mature plants, and occurred similarly in both males and females. It is concluded that (a) plant maturity reduces vegetative growth in U. dioica, (b) effects of plant maturity are evident both in reproductive and non-reproductive shoots, but particularly in the former, and (c) these changes occur similarly in both male and female plants.

  6. Bisphenol A in artificial soil: Effects on growth, reproduction and immunity in earthworms.

    Science.gov (United States)

    Verdú, I; Trigo, D; Martínez-Guitarte, J L; Novo, M

    2018-01-01

    The application of biosolids in agricultural fields is increasing annually. They contain not only nutrients but also xenobiotics, such as Bisphenol A (BPA). These compounds are not regulated in the use of biosolids in agriculture, which highlights the need to assess their effects on soil life, of which earthworms are most abundant of the animal representatives. In this study the effect of BPA on life-history parameters, such as mortality, growth and reproduction, and on immunity, is evaluated for Dendrobaena veneta and Eisenia fetida. Sublethal concentrations were evaluated by a modified OECD artificial soil test. Decline in growth with increasing concentration of BPA was detected during the first two weeks and the opposite effect for the next two, although these differences were only significant at the highest concentration. Reproduction traits were only significantly different for E. fetida, for which the number of juveniles decreased at higher concentrations, thus showing different sensitivity in both species. By using a contact test, the potentially harmful effect of direct contact with BPA was shown to be much higher than in soil (resembling natural) conditions. Finally, results indicate that BPA may not affect the immune system of these animals, at least in terms of coelomocyte viability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Prenatal corticosterone exposure programs growth, behavior, reproductive function and genes in the chicken

    Directory of Open Access Journals (Sweden)

    Abdelkareem A. Ahmed

    2016-07-01

    Full Text Available The aim of this review paper was to understand the role of prenatal corticosterone exposure on growth, aggressive behavior, reproductive performance and gene expression in the chicken. The phenotype, physiology, reproductive function and behavioral characteristics of an organism are not only influenced by genetic factors, but also by environmental factors that play a critical role in shaping offspring morphology. Exposure to excess glucocorticoids during embryonic development influences offspring growth, physiology and behaviors associated with alterations of hypothalamic-pituitary-adrenal axis, hypothalamic-pituitary-gonadal axis and serotonergic system gene expression. Another influential factor for phenotype, physiology and behavioral development is maternal derived steroid hormones that deposit in the egg. In avian species, maternal influences have aroused much attention after the discovery that avian eggs contain a variety of maternal derived steroid hormones. In addition, the environment condition during ontogeny has played a critical role in behavioral development. In avian species, for example laying chicken, high quality mother care produced chicks that were less fearful. Laying hen maternal care is found to reduce cannibalistic pecking phenomenon. Genetic selection and selection experiments will also play a critical role in animals breeding for the housing systems of the future. To optimize animal welfare and to reduce risks factors such as pecking behavior, fundamental approaches are required that merge selection of the optimal genotype with provision of a positive environment for parents and offspring, both throughout ontogeny and later life.

  8. Immune investment impairs growth, female reproduction and survival in the house cricket, Acheta domesticus.

    Science.gov (United States)

    Bascuñán-García, Ana Priscila; Lara, Carlos; Córdoba-Aguilar, Alex

    2010-02-01

    We investigated whether an immune response is associated with growth, female reproduction and survival costs in the house cricket. Using different intensities of challenge immune (implantation of one piece of nylon (1N) and two nylons (2N), with their respective sham-challenge and control groups) with body size and exoskeleton thickness as response variables, growth costs were determined for both sexes. A similar methodology was followed for reproduction costs, in which egg number and size, and female survival were measured as response variables. It was also determined whether mated and virgin females showed different immune responses. Body size decreased with immune challenge but only in the 2N treatment. Exoskeleton thickness increased in both sham-challenge groups and the 1N group but decreased in the 2N group. Egg number decreased more in the sham-challenge groups followed by the 1N and 2N groups. The 2N group showed the largest egg size at the end of the experiment. In these females, 2N group died first followed by the 1N, two nylon sham and one nylon sham groups. Finally, mated females showed a lower immune response than virgin females. These results are consistent with ecological immunity theory. The discovery of exoskeleton-related costs of immunity and injury may have important implications for experimental design in studies of the cost of immunity. Copyright 2009 Elsevier Ltd. All rights reserved.

  9. An individual reproduction model sensitive to milk yield and body condition in Holstein dairy cows.

    Science.gov (United States)

    Brun-Lafleur, L; Cutullic, E; Faverdin, P; Delaby, L; Disenhaus, C

    2013-08-01

    To simulate the consequences of management in dairy herds, the use of individual-based herd models is very useful and has become common. Reproduction is a key driver of milk production and herd dynamics, whose influence has been magnified by the decrease in reproductive performance over the last decades. Moreover, feeding management influences milk yield (MY) and body reserves, which in turn influence reproductive performance. Therefore, our objective was to build an up-to-date animal reproduction model sensitive to both MY and body condition score (BCS). A dynamic and stochastic individual reproduction model was built mainly from data of a single recent long-term experiment. This model covers the whole reproductive process and is composed of a succession of discrete stochastic events, mainly calving, ovulations, conception and embryonic loss. Each reproductive step is sensitive to MY or BCS levels or changes. The model takes into account recent evolutions of reproductive performance, particularly concerning calving-to-first ovulation interval, cyclicity (normal cycle length, prevalence of prolonged luteal phase), oestrus expression and pregnancy (conception, early and late embryonic loss). A sensitivity analysis of the model to MY and BCS at calving was performed. The simulated performance was compared with observed data from the database used to build the model and from the bibliography to validate the model. Despite comprising a whole series of reproductive steps, the model made it possible to simulate realistic global reproduction outputs. It was able to well simulate the overall reproductive performance observed in farms in terms of both success rate (recalving rate) and reproduction delays (calving interval). This model has the purpose to be integrated in herd simulation models to usefully test the impact of management strategies on herd reproductive performance, and thus on calving patterns and culling rates.

  10. Effects of lighting and air movement on temperatures in reproductive organs of plants in a closed plant growth facility

    Science.gov (United States)

    Kitaya, Y.; Hirai, H.

    Temperature increases in plant reproductive organs such as anthers and stigmas could cause fertility impediments and thus produce sterile seeds under artificial lighting conditions without adequately controlled environments in closed plant growth facilities. There is a possibility such a situation could occur in Bioregenerative Life Support Systems under microgravity conditions in space because there will be little natural convective or thermal mixing. This study was conducted to determine the temperature of the plant reproductive organs as affected by illumination and air movement under normal gravitational forces on the earth and to make an estimation of the temperature increase in reproductive organs in closed plant growth facilities under microgravity in space. Thermal images of reproductive organs of rice and strawberry were captured using infrared thermography at air temperatures of 10 11 °C. Compared to the air temperature, temperatures of petals, stigmas and anthers of strawberry increased by 24, 22 and 14 °C, respectively, after 5 min of lighting at an irradiance of 160 W m-2 from incandescent lamps. Temperatures of reproductive organs and leaves of strawberry were significantly higher than those of rice. The temperatures of petals, stigmas, anthers and leaves of strawberry decreased by 13, 12, 13 and 14 °C, respectively, when the air velocity was increased from 0.1 to 1.0 ms-1. These results show that air movement is necessary to reduce the temperatures of plant reproductive organs in plant growth facilities.

  11. Modeling reproductive trajectories of roe deer females: fixed or dynamic heterogeneity?

    Science.gov (United States)

    Plard, F; Bonenfant, C; Delormeb, D; Gaillard, J M

    2012-12-01

    The relative role of dynamic and fixed heterogeneity in shaping the individual heterogeneity observed in most life-history traits remains difficult to quantify. In a recent work, Tuljapurkar et al. (2009) suggested modeling individual heterogeneity in lifetime reproductive success by a null model building reproductive trajectories from a first-order Markov chain. According to this model, among-individual differences in reproductive trajectories would be generated by the stochastic transitions among reproductive states (such as breeder and non-breeder) due to dynamic heterogeneity. In this work, we analyze the individual variation in three reproductive metrics (reproductive status, fecundity, and reproductive success) in two populations of roe deer intensively monitored using Tuljapurkar et al. (2009)’s dynamic model. Moreover, we challenge the Tuljapurkar model previously used as a biological null model to test whether the observed distribution of reproductive success over the lifetime was generated by a stochastic process by modifying two steps of the previous model to build a full stochastic model. We show that a distribution generated by the full dynamic model proposed by Tuljapurkar et al. (2009) can be consistently interpreted as only generated from a stochastic biological process provided that the probabilities of transition among reproductive states used are independent of the current reproductive state and that the positive covariation that usually occurs between survival and reproduction among individuals is removed. Only the reproductive status of roe deer females could be restricted to a stochastic process described by the full stochastic model, probably because most females (>90%) were breeders in a given year. The fecundity of roe deer females could not be adequately described by the full dynamic and full stochastic model, and the observed distribution of female reproductive success differed from the one generated by a full dynamic model in which

  12. Reproduction numbers for epidemic models with households and other social structures II: Comparisons and implications for vaccination.

    Science.gov (United States)

    Ball, Frank; Pellis, Lorenzo; Trapman, Pieter

    2016-04-01

    In this paper we consider epidemic models of directly transmissible SIR (susceptible → infective → recovered) and SEIR (with an additional latent class) infections in fully-susceptible populations with a social structure, consisting either of households or of households and workplaces. We review most reproduction numbers defined in the literature for these models, including the basic reproduction number R0 introduced in the companion paper of this, for which we provide a simpler, more elegant derivation. Extending previous work, we provide a complete overview of the inequalities among these reproduction numbers and resolve some open questions. Special focus is put on the exponential-growth-associated reproduction number Rr, which is loosely defined as the estimate of R0 based on the observed exponential growth of an emerging epidemic obtained when the social structure is ignored. We show that for the vast majority of the models considered in the literature Rr ≥ R0 when R0 ≥ 1 and Rr ≤ R0 when R0 ≤ 1. We show that, in contrast to models without social structure, vaccination of a fraction 1-1/R0 of the population, chosen uniformly at random, with a perfect vaccine is usually insufficient to prevent large epidemics. In addition, we provide significantly sharper bounds than the existing ones for bracketing the critical vaccination coverage between two analytically tractable quantities, which we illustrate by means of extensive numerical examples. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. [Effects of Cuscuta australis parasitism on the growth, reproduction and defense of Solidago canadensis].

    Science.gov (United States)

    Yang, Bei-fen; Du, Le-shan; Li, Jun-min

    2015-11-01

    In order to find out how parasitic Cuscuta australis influences the growth and reproduction of Solidago canadensis, the effects of the parasitism of C. australis on the morphological, growth and reproductive traits of S. canadensis were examined and the relationships between the biomass and the contents of the secondary metabolites were analyzed. The results showed that the parasitism significantly reduced the plant height, basal diameter, root length, root diameter, root biomass, stem biomass, leaf biomass, total biomass, number of inflorescences branches, axis length of inflorescence, and number of inflorescence. In particular, plant height, number of inflorescence and the stem biomass of parasitized S. canadensis were only 1/2, 1/5 and 1/8 of non-parasitized plants, respectively. There was no significant difference of plant height, root length, stem biomass and total biomass between plants parasitized with high and low intensities. But the basal diameter, root volume, leaf biomass, root biomass, the number of inflorescences branches, axis length of inflorescence and number of inflorescence of S. canadensis parasitized with high intensity were significantly lower than those of plants parasitized with low intensity. The parasitism of C. australis significantly increased the tannins content in the root and the flavonoids content in the stem of S. canadensis. The biomass of S. canadensis was significantly negatively correlated with the tannin content in the root and the flavonoids content in the stem. These results indicated that the parasitism of C. australis could inhibit the growth of S. canadensis by changing the resources allocation patterns as well as reducing the resources obtained by S. canadensis.

  14. Direct and maternal genetic effects on growth, reproduction, and ultrasound traits in zebu Brahman cattle in Colombia.

    Science.gov (United States)

    Martínez, R A; Dassonneville, R; Bejarano, D; Jimenez, A; Even, G; Mészáros, G; Sölkner, J

    2016-07-01

    Covariance components and genetic parameters were estimated for birth weight (BiW); adjusted weights at 4, 7, 12, and 18 mo; and ADG between 0 and 4 mo, between 4 and 7 mo, between 7 and 12 mo, and between 12 and 18 mo. Additionally, reproductive traits, calving interval, and age at first calving were analyzed, together with traits measured by ultrasound: loin eye area, deep fat mean, back fat, and rump fat. Analyses were performed using an animal model, considering the fixed effects of the farm ( = 37), year and month of birth, sex, calving number (1 to 7), season (dry and rainy seasons), region (North Coast, Andean Region, and Oriental Savannas), and conception (natural mating or AI), whereas the age of the cows at calving was considered a polynomial covariate with linear and quadratic effects. Three different models were used to find the one with the best fit for each trait: a single-trait model with an additive direct genetic effect, a single-trait model with additive direct and maternal genetic effects, and finally, a multitrait model with an additive direct genetic effect. For the growth traits, the heritability was between 0.24 and 0.47, with the lowest value for weight at 7 mo and the greatest value for BiW, and the maternal heritability was found to be between 0.15 and 0.21 but did not decrease later on. The correlation between direct and maternal effects was high and negative (-0.59 to -0.76). With ultrasound traits, a model with only direct effects was used. The heritability was between 0.13 and 0.28 for back fat and loin eye area, respectively. The heritabilities for deep fat mean and rump fat were similar, being 0.19 and 0.21, respectively. The reproductive traits showed high residual variance. In particular, the heritability of calving interval was low (0.06). The results showed that the growth traits have an important genetic component, which is a favorable indicator for obtaining improvement progress in the zebu Brahman breed for beef production in

  15. Short- and long-term reproductive effects of prenatal and lactational growth restriction caused by maternal diabetes in male rats

    Directory of Open Access Journals (Sweden)

    Amorim Elaine MP

    2011-12-01

    Full Text Available Abstract Background A suboptimal intrauterine environment may have a detrimental effect on gonadal development and thereby increases the risk for reproductive disorders and infertility in adult life. Here, we used uncontrolled maternal diabetes as a model to provoke pre- and perinatal growth restriction and evaluate the sexual development of rat male offspring. Methods Maternal diabetes was induced in the dams through administration of a single i.v. dose of 40 mg/kg streptozotocin, 7 days before mating. Female rats presenting glycemic levels above 200 mg/dL after the induction were selected for the experiment. The male offspring was analyzed at different phases of sexual development, i.e., peripuberty, postpuberty and adulthood. Results Body weight and blood glucose levels of pups, on the third postnatal day, were lower in the offspring of diabetic dams compared to controls. Maternal diabetes also provoked delayed testicular descent and preputial separation. In the offspring of diabetic dams the weight of reproductive organs at 40, 60 and 90 days-old was lower, as well as sperm reserves and sperm transit time through the epididymis. However the plasma testosterone levels were not different among experimental groups. Conclusions It is difficult to isolate the effects directly from diabetes and those from IUGR. Although the exposure to hyperglycemic environment during prenatal life and lactation delayed the onset of puberty in male rats, the IUGR, in the studied model, did not influenced the structural organization of the male gonads of the offspring at any point during sexual development. However the decrease in sperm reserves in epididymal cauda and the acceleration in sperm transit time in this portion of epididymis may lead to an impairment of sperm quality and fertility potential in these animals. Additional studies are needed in attempt to investigate the fertility of animals with intrauterine growth restriction by maternal diabetes and

  16. Reproductive failure in Arabidopsis thaliana under transient carbohydrate limitation: flowers and very young siliques are jettisoned and the meristem is maintained to allow successful resumption of reproductive growth.

    Science.gov (United States)

    Lauxmann, Martin A; Annunziata, Maria G; Brunoud, Géraldine; Wahl, Vanessa; Koczut, Andrzej; Burgos, Asdrubal; Olas, Justyna J; Maximova, Eugenia; Abel, Christin; Schlereth, Armin; Soja, Aleksandra M; Bläsing, Oliver E; Lunn, John E; Vernoux, Teva; Stitt, Mark

    2016-04-01

    The impact of transient carbon depletion on reproductive growth in Arabidopsis was investigated by transferring long-photoperiod-grown plants to continuous darkness and returning them to a light-dark cycle. After 2 days of darkness, carbon reserves were depleted in reproductive sinks, and RNA in situ hybridization of marker transcripts showed that carbon starvation responses had been initiated in the meristem, anthers and ovules. Dark treatments of 2 or more days resulted in a bare-segment phenotype on the floral stem, with 23-27 aborted siliques. These resulted from impaired growth of immature siliques and abortion of mature and immature flowers. Depolarization of PIN1 protein and increased DII-VENUS expression pointed to rapid collapse of auxin gradients in the meristem and inhibition of primordia initiation. After transfer back to a light-dark cycle, flowers appeared and formed viable siliques and seeds. A similar phenotype was seen after transfer to sub-compensation point irradiance or CO2 . It also appeared in a milder form after a moderate decrease in irradiance and developed spontaneously in short photoperiods. We conclude that Arabidopsis inhibits primordia initiation and aborts flowers and very young siliques in C-limited conditions. This curtails demand, safeguarding meristem function and allowing renewal of reproductive growth when carbon becomes available again. © 2015 John Wiley & Sons Ltd.

  17. Viscoelastic model of tungsten 'fuzz' growth

    International Nuclear Information System (INIS)

    Krasheninnikov, S I

    2011-01-01

    A viscoelastic model of fuzz growth is presented. The model describes the main features of tungsten fuzz observed in experiments. It gives estimates of fuzz growth rate and temperature range close to experimental ones.

  18. The sublethal effects of the organochlorines dieldrin and lindane on growth and reproduction of Eudrilus eugeniae and Eisenia fetida (Oligochaeta

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1994-07-01

    Full Text Available Experimental exposure of the earthworm species Eudrilus eugeniae to organochlorines showed that dieldrin causes damage to sperm ultrastructure when viewed electronmicroscopically. Worms containing concentrations of 7,27 mg/kg dieldrin and higher showed more than 10% sperm damage. Exposure of Eisenia fetida to sublethal concentrations of lindane did not result in sperm damage but demonstrated an increase in growth and reproductive activity. It is argued that quantification of sperm damage and correlation with pesticide concentration could provide a useful tool for evaluating environmental quality. Furthermore, the effects of sublethal concentrations of pesticides that manifest themselves in increased growth and reproductive activity could affect ecological balances.

  19. Effect of horn fly (Haematobia irritans) control on growth and reproduction of beef heifers.

    Science.gov (United States)

    DeRouen, S M; Foil, L D; MacKay, A J; Franke, D E; Sanson, D W; Wyatt, W E

    2003-10-01

    The influence of horn fly control with commercially available ear tags was studied on beef replacement heifers (n = 670) for growth and reproductive performance. The study was conducted at five sites in Louisiana over 3 yr. Heifers used were yearling replacement females that were exposed to fertile bulls during a limited spring breeding season that coincided with the horn fly season. In mid to late May of each year, heifers were randomly assigned to one of two horn fly treatments: untreated and treated for horn fly control. The trial continued each year until September or October at the end of fly season. Pregnancy status was determined by rectal palpation. Horn fly populations were controlled on the treated heifers at moderate levels (84%). Total weight gain of treated heifers was 14% greater than for untreated heifers. Horn fly treatment had no effect on pregnancy rate (78% and 75% for untreated and treated heifers, respectively). Treatment differences for weight gain were of greater magnitude for heifers failing to conceive than for heifers that became pregnant. Weight gains of nonpregnant treated heifers were 33% greater than for nonpregnant untreated heifers, whereas weight gains of pregnant treated heifers were 8% greater than for pregnant untreated heifers. In conclusion, horn fly control on yearling beef replacement heifers improved weight gain but had no effect on first exposure reproduction.

  20. Developmental exposure to a brominated flame retardant: An assessment of effects on physiology, growth, and reproduction in a songbird, the zebra finch

    International Nuclear Information System (INIS)

    Eng, Margaret L.; Williams, Tony D.; Elliott, John E.

    2013-01-01

    Mixtures of polybrominated diphenyl ethers (PBDEs) have been widely used as additive flame retardants, and BDE-99 is one of the most predominant congeners found in the environment. BDE-99 has been reported in avian samples worldwide, yet knowledge of its toxicity to birds is minimal. We assessed the short- and long-term effects of nestling exposure to environmentally relevant levels of BDE-99 in a model passerine, the zebra finch. Early exposure to BDE-99 did not affect hematocrit, oxidative stress, or thyroid hormones in either the juvenile or adult stages, and there were no effects on chick growth or survival. BDE-99 exposure caused a dose-dependent delay in timing of reproduction, but there were no other effects on reproductive success. In zebra finches, endpoints related to reproductive behavior appear to be the most sensitive to BDE-99. However, passerines overall appear to be less sensitive than birds of prey or mammals to PBDE exposure. -- Highlights: •We exposed zebra finches nestlings to BDE-99 and raised them to sexual maturity. •Found no effects on physiology, chick growth, survival, or reproductive success. •As BDE-99 dose increased, laying interval increased. •Passerine birds possibly less sensitive to BDE-99 than mammals or other bird species. -- Nestling exposure to BDE-99 affects timing of breeding in zebra finches, but overall passerines appear to be less sensitive to PBDEs than mammals or other bird species

  1. Mouse models of altered gonadotrophin action: insight into male reproductive disorders.

    Science.gov (United States)

    Jonas, Kim C; Oduwole, Olayiwola O; Peltoketo, Hellevi; Rulli, Susana B; Huhtaniemi, Ilpo T

    2014-10-01

    The advent of technologies to genetically manipulate the mouse genome has revolutionised research approaches, providing a unique platform to study the causality of reproductive disorders in vivo. With the relative ease of generating genetically modified (GM) mouse models, the last two decades have yielded multiple loss-of-function and gain-of-function mutation mouse models to explore the role of gonadotrophins and their receptors in reproductive pathologies. This work has provided key insights into the molecular mechanisms underlying reproductive disorders with altered gonadotrophin action, revealing the fundamental roles of these pituitary hormones and their receptors in the hypothalamic-pituitary-gonadal axis. This review will describe GM mouse models of gonadotrophins and their receptors with enhanced or diminished actions, specifically focusing on the male. We will discuss the mechanistic insights gained from these models into male reproductive disorders, and the relationship and understanding provided into male human reproductive disorders originating from altered gonadotrophin action. © 2014 Society for Reproduction and Fertility.

  2. Mudcake growth: Model and implications

    KAUST Repository

    Liu, Q.

    2017-12-15

    Oil and gas account for 60% of the world\\'s energy consumption. Drilling muds that are used to advance oil and gas wells must be engineered to avoid wellbore integrity problems associated with mud cake formation, to favor cake erosion during cementing, and to prevent partial differential sticking. We developed a robust mud cake growth model for water-based mud based on wide stress-range constitutive equations within a Lagrangian reference system to avoid non-natural moving boundary solutions. The comprehensive mud cake growth model readily accommodates environmental factors (e.g., temperature, pH, and ionic concentration) and defines the yield stress distribution for displacement-erosion analyses. Results show that the mud cake thickness is more sensitive to time than to filtration pressure, therefore, time controls the non-uniform distribution of mudcake thickness during drilling. Long filtration time, high permeability, high salinity, high in-situ temperature and low viscosity exacerbate fluid loss and give rise to thick filter cakes. The analysis of residual cake thickness during cement displacement must take into account the effective stress dependent mudcake formation and the time-dependent mud thixotropy. Thixotropy dominates the mud yield stress at high void ratios, e.g. e > 20. The offsetting force that causes differential pressure sticking increases sub-linearly as a power function of the still-time.

  3. [Growth and reproduction of the shrimp Atya margaritacea (Decapoda: Atyidae) in Rio Presidio, Sinaloa, Mexico].

    Science.gov (United States)

    Sánchez Palacios, Jesús; Alvarez, Rigoberto Beltrán; Ramírez Lozano, Juan Pedro

    2008-06-01

    Some growth and reproduction parameters of the population of the shrimp Atya margaritacea in Presidio River (Sinaloa, NW Mexico) were studied using 542 organisms collected with a Surber net in five sampling locations distributed from mid- to low river. Total lengths and gross weights ranged from 15 to 96 mm and 0.1 to 25.2 g. The male:female ratio was 1.96:1 and males had larger sizes and weights. The relations of total length (Lt) to gross weight (Pt) were Pt = 1.02 x 10(-5) (Lt)32089 for males and Pt = 2.29 x 10(-5) (Lt)3.0159 for females. Growth in males was positively allometric whereas in females it was isometric. The regressions between total lengths and cephalothorax (Lc) were Log Lc = 1.1118 (Log Lt)- 0.6087 for males and Log Lc = 0.9945 (Log Lt)- 0.4321 for females. The relative growth between these body parts was allometrically positive in males and isometric in females; this result indicates a clear sexual dimorphism. Ovigerous females appeared in the rainy season (July to November). The absolute fecundity ranged from 1860 to 22400 eggs in females of 43 to 59 mm in length and 1.9 to 6.0 g in weight. The equations relating the number of eggs to length and weight were Fec = 8.3 x 10(-7) (Lt)5.8053 and Fec = 732 (Pt)1.836 respectively.

  4. Evidence of developmental niche construction in dung beetles: effects on growth, scaling and reproductive success.

    Science.gov (United States)

    Schwab, Daniel B; Casasa, Sofia; Moczek, Armin P

    2017-11-01

    Niche construction occurs when organisms modify their environments and alter selective conditions through their physiology and behaviours. Such modifications can bias phenotypic variation and enhance organism-environment fit. Yet few studies exist that experimentally assess the degree to which environmental modifications shape developmental and fitness outcomes, how their influences may differ among species and identify the underlying proximate mechanisms. Here, we experimentally eliminate environmental modifications from the developmental environment of Onthophagus dung beetles. We show that these modifications (1) differentially influence growth among species, (2) consistently shape scaling relationships in fitness-related traits, (3) are necessary for the maintenance of sexual dimorphism, (4) influence reproductive success among females of at least one species and (5) implicate larval cultivation of an external rumen as a possible mechanism for environmental modification. Our results present evidence that Onthophagus larvae engage in niche construction, and that this is a fundamental component of beetle development and fitness. © 2017 John Wiley & Sons Ltd/CNRS.

  5. Predation risk affects growth and reproduction of an invasive snail and its lethal effect depends on prey size

    Science.gov (United States)

    Guo, Jing; Martín, Pablo R.; Zhang, Chunxia

    2017-01-01

    The behavior of invasive species under predation risk has been studied extensively, but their growth and reproductive responses have rarely been investigated. We conducted experiments with juveniles and adults of the invasive freshwater snail Pomacea canaliculata, and we observed changes in growth and reproduction in response to predation risk from a caged predator (Trachemys scripta elegans). P. canaliculata produced eggs earlier in the presence of predators and injured conspecifics compared with the control group (no risk), although the total number of egg masses laid by per female was exceeded by that of the controls after 15 days. Egg hatching success noticeably decreased under predation risk, and the incubation period was significantly prolonged; however, the oviposition height of the snails was not affected. A lethal effect of predation risk was detected in juvenile snails but not in adults. The growth of juvenile P. canaliculata was inhibited under predation risk, probably due to a reduction in food intake. Adult females exhibited a greater reduction in growth under predation risk than males, which likely resulted in part from the high reproductive investment of females in egg laying. These results indicate that P. canaliculata snails under predation risk face a trade-off between predator avoidance and growth and reproduction, where the lethal effect of predation risk is linked to the size of the prey. PMID:29136660

  6. Predation risk affects growth and reproduction of an invasive snail and its lethal effect depends on prey size.

    Directory of Open Access Journals (Sweden)

    Jing Guo

    Full Text Available The behavior of invasive species under predation risk has been studied extensively, but their growth and reproductive responses have rarely been investigated. We conducted experiments with juveniles and adults of the invasive freshwater snail Pomacea canaliculata, and we observed changes in growth and reproduction in response to predation risk from a caged predator (Trachemys scripta elegans. P. canaliculata produced eggs earlier in the presence of predators and injured conspecifics compared with the control group (no risk, although the total number of egg masses laid by per female was exceeded by that of the controls after 15 days. Egg hatching success noticeably decreased under predation risk, and the incubation period was significantly prolonged; however, the oviposition height of the snails was not affected. A lethal effect of predation risk was detected in juvenile snails but not in adults. The growth of juvenile P. canaliculata was inhibited under predation risk, probably due to a reduction in food intake. Adult females exhibited a greater reduction in growth under predation risk than males, which likely resulted in part from the high reproductive investment of females in egg laying. These results indicate that P. canaliculata snails under predation risk face a trade-off between predator avoidance and growth and reproduction, where the lethal effect of predation risk is linked to the size of the prey.

  7. Insulin-like growth factor-I as a possible hormonal mediator of nutritional regulation of reproduction in cattle.

    Science.gov (United States)

    Zulu, Victor Chisha; Nakao, Toshihiko; Sawamukai, Yutaka

    2002-08-01

    The current review aims to establish insulin-like growth factor-1 (IGF-I) as the factor that signals nutritional status to the reproductive axis, and show that assessment of IGF-I in blood early postpartum during the negative energy balance (NEB) period could be used to predict both nutritional and reproductive status in dairy cattle. The review also explores the effect of nutritional status on circulating IGF-I concentrations and the endocrine role of IGF-I on the reproductive axis. IGF-I plays an important role in gonadotropin-induced folliculogenesis, ovarian steroidogenesis and corpus luteum (CL) function. It also modulates pituitary and hypothalamus function. IGF-I clearly has an endocrine role on the reproductive axis. Severe under nutrition significantly reduces plasma IGF-I concentrations. During the critical period of NEB in high yielding dairy cattle early postpartum, IGF-I concentrations are low in blood and its levels are positively correlated to energy status and reproductive function during this period. Changes in circulating IGF-I immediately postpartum may help predict both nutritional and reproductive status in dairy cattle. IGF-I is therefore one of the long sought factors that signal nutritional status to the reproductive axis.

  8. Growth and Reproduction of Glyphosate-Resistant and Susceptible Populations of Kochia scoparia

    Science.gov (United States)

    Kumar, Vipan; Jha, Prashant

    2015-01-01

    Evolution of glyphosate-resistant kochia is a threat to no-till wheat-fallow and glyphosate-resistant (GR) cropping systems of the US Great Plains. The EPSPS (5-enol-pyruvylshikimate-3-phosphate synthase) gene amplification confers glyphosate resistance in the tested Kochia scoparia (L.) Schrad populations from Montana. Experiments were conducted in spring to fall 2014 (run 1) and summer 2014 to spring 2015 (run 2) to investigate the growth and reproductive traits of the GR vs. glyphosate-susceptible (SUS) populations of K. scoparia and to determine the relationship of EPSPS gene amplification with the level of glyphosate resistance. GR K. scoparia inbred lines (CHES01 and JOP01) exhibited 2 to 14 relative copies of the EPSPS gene compared with the SUS inbred line with only one copy. In the absence of glyphosate, no differences in growth and reproductive parameters were evident between the tested GR and SUS inbred lines, across an intraspecific competition gradient (1 to 170 plants m-2). GR K. scoparia plants with 2 to 4 copies of the EPSPS gene survived the field-use rate (870 g ha-1) of glyphosate, but failed to survive the 4,350 g ha-1 rate of glyphosate (five-times the field-use rate). In contrast, GR plants with 5 to 14 EPSPS gene copies survived the 4,350 g ha-1 of glyphosate. The results from this research indicate that GR K. scoparia with 5 or more EPSPS gene copies will most likely persist in field populations, irrespective of glyphosate selection pressure. PMID:26580558

  9. Growth performance, reproductive traits and offspring survivability of genetically modified rams overexpressing toll-like receptor 4.

    Science.gov (United States)

    Yao, Yu-Chang; Han, Hong-Bing; Song, Xu-Ting; Deng, Shou-Long; Liu, Yu-Feng; Lu, Ming-Hai; Zhang, Yun-Hai; Qi, Mei-Yu; He, Hai-Juan; Wang, Su-Mei; Liu, Guo-Shi; Li, Wu; Lian, Zheng-Xing

    2017-07-01

    Genetic modification provides a means to enhancing disease resistance in animals. Toll-like receptor 4 (TLR4), a member of the TLR family, is critical for the recognition of lipopolysaccharide (LPS)/endotoxin from Gram-negative bacteria by host immune cells, which initiates cell activation and subsequently triggers a proinflammatory response to the invading pathogens. In this study, the first generation of genetically modified (GM) sheep overexpressing TLR4 was produced by microinjection for better disease resistance. Compared with wild-type (WT) rams, the GM rams have similar growth performance, basic semen quality and spermatozoon ultrastructure. The offspring birth rates after cervical artificial insemination were also similar between GM (90.32%) and WT (92.38%) rams. Overall, the presence and expression of the TLR4 transgene in the genome did not appear to interfere with normal semen production, reproductive traits and the ability of transgene transmission to offspring. The expression levels of TLR4, tumor necrosis factor and interferon gamma genes in monocyte/macrophages from GM sheep were significantly higher than that from WT sheep at early stages after LPS stimulation. The GM offspring born from the founder transgenic ram inseminated ewes had similar survival rate with WT offspring (88.89% vs 84.86%) at weaning. The TLR4 transgene showed no deleterious effects on growth performance, reproductive traits and offspring survivability of GM rams. Therefore, the GM sheep overexpressing TLR4 provide a powerful experimental model for analyzing function of TLR4 in vivo during infection and inflammation. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. The impact of early life nutrition and housing on growth and reproduction in dairy cattle.

    Science.gov (United States)

    Curtis, G; McGregor Argo, C; Jones, D; Grove-White, D

    2018-01-01

    Contentious issues in calf rearing include milk feeding practices and single versus group housing. The current study was performed on a high producing 170 Holstein cow dairy farm, to investigate the impact of nutrition and housing on growth and reproduction. Heifer calves (n = 100) were allocated in birth order to one of two commonly used management strategies. All calves received 3-4 litres of dam specific colostrum within 6 hours of birth. Group A calves were group housed from birth and fed milk replacer (MR) ad libitum via a computerised machine utilising a single teat, with weaning commencing at 63 days of age. Group R calves were initially housed in individual pens and received 2.5 litres of MR twice daily via a bucket until 21 days of age when they were group housed and fed 3 litres of MR twice daily via a group trough with weaning commencing at 56 days. From 12 weeks of age onwards, calves in both dietary groups were subject to common nutritional and husbandry protocols. All breeding of heifers was via artificial insemination with no hormonal intervention. Calves were weighed, body condition scored and morphometric measures recorded weekly up till 12 weeks of age then monthly until conception. Pre-weaning growth rates (kg/day) were significantly higher in Group A calves compared to Group R (0.89, 95% CI 0.86-0.93 vs 0.57, 95% CI 0.54-0.6 kg/day P 0.050) in any of the mean values of measured reproductive parameters, multivariable Cox regression suggested that there was a weak trend (P = 0.072) for Group A animals to achieve first service earlier than their Group R counterparts (62.6 weeks versus 65.3 weeks). Irrespective of dietary group, the hazard for achievement of all measured reproductive parameters, apart from time to puberty, was 20-40% less for heifers borne from multiparous dams compared to heifers from primiparous dams.

  11. A model for estimating the minimum number of offspring to sample in studies of reproductive success.

    Science.gov (United States)

    Anderson, Joseph H; Ward, Eric J; Carlson, Stephanie M

    2011-01-01

    Molecular parentage permits studies of selection and evolution in fecund species with cryptic mating systems, such as fish, amphibians, and insects. However, there exists no method for estimating the number of offspring that must be assigned parentage to achieve robust estimates of reproductive success when only a fraction of offspring can be sampled. We constructed a 2-stage model that first estimated the mean (μ) and variance (v) in reproductive success from published studies on salmonid fishes and then sampled offspring from reproductive success distributions simulated from the μ and v estimates. Results provided strong support for modeling salmonid reproductive success via the negative binomial distribution and suggested that few offspring samples are needed to reject the null hypothesis of uniform offspring production. However, the sampled reproductive success distributions deviated significantly (χ(2) goodness-of-fit test p value reproductive success distribution at rates often >0.05 and as high as 0.24, even when hundreds of offspring were assigned parentage. In general, reproductive success patterns were less accurate when offspring were sampled from cohorts with larger numbers of parents and greater variance in reproductive success. Our model can be reparameterized with data from other species and will aid researchers in planning reproductive success studies by providing explicit sampling targets required to accurately assess reproductive success.

  12. Growth and reproductive biology of the amphidromous shrimp Palaemon pandaliformis (Decapoda: Caridea in a Neotropical river from northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Lucas R.P. Paschoal

    Full Text Available ABSTRACT Population biology, growth and reproductive aspects of the amphidromous shrimp Palaemon pandaliformis (Stimpson, 1871 were investigated in a Neotropical river of northeastern Brazil. The specimens were collected every month from September 2009 to August 2010. Total and monthly sex ratios deviated in favour of males. Von Bertalanffy growth parameters indicated that the females grew more rapidly, reached larger sizes, and had a longer life span than males. We also observed continuous reproductive activity and juvenile recruitment throughout the year. Relations between the number of eggs (fecundity and body size indicated that fecundity in females increase with size. Compared with previous results, some population biology parameters of the freshwater population of P. pandaliformis differ from estuarine populations. The reproductive aspects analyzed here and their comparison with other marine species were consistent with the hypothesis that Palaemonidae species are undergoing an adaptation process and colonizing fresh water environments.

  13. A trade-off between reproduction and feather growth in the barn swallow (Hirundo rustica.

    Directory of Open Access Journals (Sweden)

    Nicola Saino

    Full Text Available Physiological trade-offs mediated by limiting energy, resources or time constrain the simultaneous expression of major functions and can lead to the evolution of temporal separation between demanding activities. In birds, plumage renewal is a demanding activity, which accomplishes fundamental functions, such as allowing thermal insulation, aerodynamics and socio-sexual signaling. Feather renewal is a very expensive and disabling process, and molt is often partitioned from breeding and migration. However, trade-offs between feather renewal and breeding have been only sparsely studied. In barn swallows (Hirundo rustica breeding in Italy and undergoing molt during wintering in sub-Saharan Africa, we studied this trade-off by removing a tail feather from a large sample of individuals and analyzing growth bar width, reflecting feather growth rate, and length of the growing replacement feather in relation to the stage in the breeding cycle at removal and clutch size. Growth bar width of females and length of the growing replacement feather of both sexes were smaller when the original feather had been removed after clutch initiation. Importantly, in females both growth bar width and replacement feather length were negatively predicted by clutch size, and more strongly so for large clutches and when feather removal occurred immediately after clutch completion. Hence, we found strong, coherent evidence for a trade-off between reproduction, and laying effort in particular, and the ability to generate new feathers. These results support the hypothesis that the derived condition of molting during wintering in long-distance migrants is maintained by the costs of overlapping breeding and molt.

  14. Fragmentation in the branching coral Acropora palmata (Lamarck): growth, survivorship, and reproduction of colonies and fragments.

    Science.gov (United States)

    Lirman

    2000-08-23

    Acropora palmata, a branching coral abundant on shallow reef environments throughout the Caribbean, is susceptible to physical disturbance caused by storms. Accordingly, the survivorship and propagation of this species are tied to its capability to recover after fragmentation. Fragments of A. palmata comprised 40% of ramets within populations that had experienced recent storms. While the survivorship of A. palmata fragments was not directly related to the size of fragments, removal of fragments from areas where they settled was influenced by size. Survivorship of fragments was also affected by type of substratum; the greatest mortality (58% loss within the first month) was observed on sand, whereas fragments placed on top of live colonies of A. palmata fused to the underlying tissue and did not experience any losses. Fragments created by Hurricane Andrew on a Florida reef in August 1992 began developing new growth (proto-branches) 7 months after the storm. The number of proto-branches on fragments was dependent on size, but growth was not affected by the size of fragments. Growth-rates of proto-branches increased exponentially with time (1.7 cm year(-1) for 1993-1994, 2.7 cm year(-1) for 1994-1995, 4.2 cm year(-1) for 1995-1996, and 6.5 cm year(-1) for 1996-1997), taking over 4 years for proto-branches to achieve rates comparable to those of adult colonies on the same reef (6.9 cm year(-1)). In addition to the initial mortality and reduced growth-rates, fragmentation resulted in a loss of reproductive potential. Neither colonies that experienced severe fragmentation nor fragments contained gametes until 4 years after the initial damage. Although A. palmata may survive periodic fragmentation, the long-term effects of this process will depend ultimately on the balance between the benefits and costs of this process.

  15. The toxicity of a mixture of two antiseptics, triclosan and triclocarban, on reproduction and growth of the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Vingskes, Anna Katharina; Spann, Nicole

    2018-05-01

    Many widely used healthcare products contain antiseptics, whose persistence in aquatic environments, soils, and sediments leads to the contamination of ecosystems and adversely affects wildlife. Recently, the impact not only of high but also low doses of contaminants and mixtures of several chemicals has become a focus of concern. In this study, toxicity tests of the antiseptics triclosan (TCS) and triclocarban (TCC) were performed in an aquatic test medium using the nematode Caenorhabditis elegans. Nominal concentrations of TCS and TCC were tested in separate single-substance toxicity tests (96-h-exposure), focussing on growth and reproduction endpoints. Median effective concentrations (EC50s) from the single-substance tests were subsequently used to set up five different ratios of TCS:TCC mixtures leading to the same toxicity. Six dilutions of each mixture ratio were tested for effon reproduction of C. elegans. In the single-substance tests, TCC was about 30 times more toxic than TCS when considering effects on growth and concerning reproduction, TCC was about 50 times more toxic than TCS. For both substances, the toxic effect on reproduction was more pronounced than the one on growth. Low doses of TCS (1-10 µmol L -1 ) stimulated reproduction by up to 301% compared to the control, which might be due to endocrine disruption or other stress-related compensation responses (hormesis). Neither antiseptic stimulated growth. In the mixtures, increasing amounts of TCC inhibited the stimulatory effects of TCS on reproduction. In addition, the interactions of TCS and TCC were antagonistic, such that mixtures displayed lower toxicity than would have been expected when TCS and TCC mixtures adhered to the principle of concentration addition.

  16. Reproductive parameters of double transgenic zebrafish (Danio rerio) males overexpressing both the growth hormone (GH) and its receptor (GHR).

    Science.gov (United States)

    Silva, Ana Cecilia Gomes; Almeida, Daniela Volcan; Nornberg, Bruna Felix; Pereira, Jessica Ribeiro; Pires, Diego Martins; Corcini, Carine Dahl; Junior, Antonio Sergio Varela; Marins, Luis Fernando

    2017-02-01

    Growth hormone (GH) transgenesis presents a high potential application in aquaculture. However, excess GH may have serious consequences due to pleiotropic actions. In order to study these effects in zebrafish (Danio rerio), two transgenic lines were developed. The first expresses GH ubiquitously and constitutively (F0104 line), while the second expresses the GH receptor in a muscle-specific manner (Myo-GHR line). Results from the F0104 line showed accelerated growth but increased reproductive difficulties, while Myo-GHR did not show the expected increase in muscle mass. Since the two lines appeared to display complementary characteristics, a double transgenic (GH/GHR) was created via crossing between them. This double transgenic displayed accelerated growth, however reproductive parameters remained uncertain. The objective of the present study was to determine the reproductive capacity of males of this new line, by evaluating sperm parameters, expression of spermatogenesis-related genes, and reproductive tests. Double transgenics showed a strong recovery in almost all sperm parameters analyzed when compared to the F0104 line. Gene expression analyses revealed that Anti-Müllerian Hormone gene (amh) appeared to be primarily responsible for this recovery. Reproductive tests showed that double transgenic males did not differ from non-transgenics. It is possible that GHR excess in the muscle tissues of double transgenics may have contributed to lower circulating GH levels and thus reduced the negative effects of this hormone with respect to reproduction. Therefore, it is clear that GH-transgenesis technology should take into account the need to obtain adequate levels of circulating hormone in order to achieve maximum growth with minimal negative side effects.

  17. Complexities and contingencies conceptualised: towards a model of reproductive navigation

    NARCIS (Netherlands)

    van der Sijpt, E.

    2014-01-01

    Current international attention to reproductive health behaviour is inspired by a western celebration of individual rights, autonomous action and rational choice. A predominant idea is that individuals should be free to act in accordance with their reproductive intentions and that, in doing so, they

  18. Effects of symbiotic bacteria and tree chemistry on the growth and reproduction of bark beetle fungal symbionts

    Science.gov (United States)

    A.S. Adams; C.R. Currie; Y. Cardoza; K.D. Klepzig; K.F. Raffa

    2009-01-01

    Bark beetles are associated with diverse assemblages of microorganisms, many of which affect their interactions with host plants and natural enemies. We tested how bacterial associates of three bark beetles with various types of host relationships affect growth and reproduction of their symbiotic fungi. Fungi were exposed to volatiles...

  19. Field biology of Halimeda tuna (Bryopsidales, Chlorophyta) across a depth gradient : comparative growth, survivorship, recruitment, and reproduction

    NARCIS (Netherlands)

    Vroom, P.S.; Smith, C.M.; Coyer, J.A.; Walters, L.; Hunter, C.L.; Beach, K.S.; Smith, J.E.

    Growth, survivorship, recruitment, and reproduction of Halimeda tuna, a dominant green alga in many reef systems of the Florida Keys, were monitored at a shallow back reef ( 4 - 7m) and deep reef slope ( 15 - 22 m) on Conch Reef. Despite lower light intensities and similar grazing pressures,

  20. Dietary effects on growth, reproduction, body composition and stress resistance in the terrestrial isopods Oniscus asellus and Porcellio scaber.

    NARCIS (Netherlands)

    Lavy, D.; van Rijn, M.J.; Zoomer, H.R.; Verhoef, H.A.

    2001-01-01

    The effect of differences in food composition on growth, body composition and cold tolerance of the isopods Porcellio scaber (Latreille) and Oniscus asellus (L.) has been studied. The effect on reproduction of P. scaber was included. Total lipid and protein content remained the same in O. asellus,

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

    Directory of Open Access Journals (Sweden)

    Gutiérrez Alfredo

    2002-01-01

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

  2. Parity-specific and two-sex utility models of reproductive intentions.

    Science.gov (United States)

    Fried, E S; Hofferth, S L; Udry, J R

    1980-02-01

    This paper uses married couples' anticipated consequences of having a (another) child to predict their reproductive intentions. Parity-specific models identify different variables as predictors of reproductive behavior at different parities but do not yield interpretable patterns of difference by parity. Parity-specific models are not significantly stronger predictors of reproductive behavior. Generally, wife-only models are distinctly superior to husband-only models. Two-sex models are usually better predictors than one-sex models but not enough better to justify the additional cost.

  3. Mathematical modeling of microbial growth in milk

    Directory of Open Access Journals (Sweden)

    Jhony Tiago Teleken

    2011-12-01

    Full Text Available A mathematical model to predict microbial growth in milk was developed and analyzed. The model consists of a system of two differential equations of first order. The equations are based on physical hypotheses of population growth. The model was applied to five different sets of data of microbial growth in dairy products selected from Combase, which is the most important database in the area with thousands of datasets from around the world, and the results showed a good fit. In addition, the model provides equations for the evaluation of the maximum specific growth rate and the duration of the lag phase which may provide useful information about microbial growth.

  4. SELENIUM AND VITAMIN-E-DEFICIENCY IN PIGS .1. INFLUENCE ON GROWTH AND REPRODUCTION

    DEFF Research Database (Denmark)

    Nielsen, H.E.; Danielsen, V.; Simesen, M.G.

    1979-01-01

    on growth rate and feed utilization. Low dietary Se and vitamin E were followed by increased mortality rate in piglets; iron toxicity following Fe treatment was observed in piglets given low dietary vitamin E. Signs characteristic of Pale Soft Exudative (PSE) meat were not observed in the deprived pigs......1. Pigs, 28 castrated males and 32 females were weaned at 3 weeks old. Males were killed at about 85 kg bodyweight. Females remained in the 4 experimental groups and were mated at the first oestrus after 7 months of age. Two from each group were mated for a total of 4 litters. Altogether 165 pigs.......ADDITIONAL ABSTRACT:In this study of the effect of 2 levels of dietary Se (0.03 and 0.06 mg/kg feed) with and without vitamin E supplement (30 IU/kg feed) on the growth and reproduction of pigs, their effects on Se and vitamin E in colostrum and milk were also examined. Concn. of Se in colostrum and milk from pigs...

  5. Effect of temperature on growth and reproduction of the epigeic earthworm, Eudrilus Eugeniae (Kinberg).

    Science.gov (United States)

    Shagoti, U M; Amoji, S D; Biradar, V A; Biradar, P M

    2001-07-01

    Influence of temperature on growth and reproduction of Eudrilus eugeniae has been investigated by laboratory culturing at regulated 25.0 degrees C, 30.0 degrees C, 37.5 degrees C and 40.0 degrees C and in fluctuating (22.7-27.3 degrees C) room temperature of prevailing (winter) season over 16 weeks. All worms died during first and tenth week at 40.0 degrees C and 37.5 degrees C respectively. Weight (biomass) and growth of worms cultured at different temperature varied significantly (Pwom/week and the cumulative cocoon number of 10.8 and 14.7/worm over 16th week respectively. The fluctuating temperature of uncontrolled room environment and 30.0 degrees C were favorable for various life activities of the worms. Eudrilus eugeniae appears to have range of temperature optima more than 25.0 degrees C and less than 28 degrees C. The climatic conditions prevailing in whole of the peninsular India during winter season are favourable for employing this worm in intensive field scale vermiculturing practices.

  6. Effects of continuous ivermectin treatment from birth to puberty on growth and reproduction in dairy heifers.

    Science.gov (United States)

    Mejía, M; Gonzalez-Iglesias, A; Díaz-Torga, G S; Villafañe, P; Formía, N; Libertun, C; Becú-Villalobos, D; Lacau-Mengido, I M

    1999-06-01

    The effect of continuous ivermectin treatment from birth to puberty on growth and reproductive performance was studied in Holstein heifer calves grown on pastures in comparison to naturally nematode-infected, untreated animals. Ivermectin effectively abated the presence of nematode eggs in feces. Eggs per gram (EPG) in parasitized animals increased rapidly from wk 12 to 18 of age and then decreased. Animals treated with ivermectin grew faster than untreated ones, and differences in body weight became significant at 6 wk of life, even before eggs appeared in the feces of either treatment group. Ivermectin-treated heifers reached puberty 3 wk earlier than infected ones as assessed with serum progesterone concentrations (ivermectin, 30.4 +/- .8 vs untreated, 33.7 +/- 1.3 wk of age). This delay was not directly related to body weight. In addition, pelvic area at 39 wk and at 15 mo of age was increased in treated heifers (8 and 11%, respectively) compared with parasitized animals. No differences in the wither heights were observed. We conclude that ivermectin treatment in dairy heifers may increase growth rate during development, advance the onset of ovarian function, and positively affect yearling pelvic area.

  7. Infection of growing swine with porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae — Effects on growth, serum metabolites, and insulin-like growth factor-I.

    OpenAIRE

    Roberts, N. Elizabeth; Almond, Glen W.

    2003-01-01

    This study evaluated the influence of concomitant infections with porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae on growth performance, serum metabolite concentrations, and serum insulin-like growth factor-I (IGF-I) in growing pigs. Twenty-two barrows (10 weeks of age) were treated with either an intranasal administration of PRRSV and an intratracheal infusion of M. hyopneumoniae (treatment; n = 8) or a sham inoculation with medium (sham; n = 8), or w...

  8. The effect of feeding dairy heifers diets with and without supplemental phosphorus on growth, reproductive efficiency, health, and lactation performance.

    Science.gov (United States)

    Bjelland, D W; Weigel, K A; Hoffman, P C; Esser, N M; Coblentz, W K

    2011-12-01

    The phosphorus requirements for dairy heifers (0.20-0.35%) and endogenous concentrations (0.20-35%) of P in feeds fed to dairy heifers are similar, suggesting that the need for supplemental P in dairy heifer diets may be minimal. Because long-term P feeding studies on dairy heifers are unavailable, 183 Holstein heifers and 182 backcross Holstein × Jersey heifers were offered diets with (SP=0.40% of dry matter) and without (NP=0.30% of dry matter) supplemental P from 4 to 22 mo of age in a replicated pen design. Forty-eight pens of 8 heifers each were split evenly by breed and treatment group. Heifers were evaluated for body weight (BW), external bone/frame growth, dystocia, calf BW, reproductive efficiency, and first-lactation performance. Growth phase data were analyzed using pen-based statistical models, and lactation data were analyzed using mixed linear models with effects of season of birth, age of dam, heifer pen, sire, sire birth year, and days in milk. Heifers fed NP had similar average daily gain from 170 to 410 and from 410 to 650 d of age compared with heifers fed SP. At 22 mo of age, heifers fed NP did not differ in BW, hip height, hip width, body length, heart girth, cannon bone circumference, or pelvic area compared with heifers fed SP. Blood P concentrations between heifers fed SP or NP did not differ at 8 or 18 mo of age, and heifers fed SP excreted more P (29.2 vs. 24.2g/d) than heifers fed NP. As heifers, services per conception and age at pregnancy were not different between heifers fed NP or SP. At parturition, heifers fed NP or SP had similar dystocia scores and calves were similar in BW. Complete first-lactation data (305 d) were available for 333 primiparous cows, and cows fed NP as heifers produced similar milk, fat, and protein compared with cows fed SP as heifers. Days open, days in milk at first breeding, and services per conception also were similar for primiparous cows fed NP or SP as heifers. No growth, reproductive, or lactation

  9. Effect of diet supplementation on growth and reproduction in camels under arid range conditions

    Directory of Open Access Journals (Sweden)

    Abdouli H.

    2001-01-01

    Full Text Available Eighteen pregnant dromedary females (Camelus dromedarius were used to determine the effect of concentrate supplement on growth and reproductive performances in peri-partum period. The females were divided into supplemented (n = 9; S and unsupplemented (n = 9; C experimental groups. All animals grazed, with one mature male, 7 to 8 hours per day on salty pasture rangelands. During night, they were kept in pen, where each female of group S received 4 kg per day of concentrate supplement during the last 3 months of gestation and 5 kg per day during the first 3 months post-partum. During the last 90 days of gestation daily body weight gain (DBG was at least tenfold more important in group S than in group C (775 g vs. 72 g respectively. Supplementation affected birth weight of offspring (30.3 kg vs. 23.4 kg and its DBG (806 g vs. 430 g in group S and group C respectively. During the post-partum period, females in group S gained in weight (116 g per day whereas females in group C lost more than 200 g per day. The mean post-partum interval to the first heat and the percentage of females in heat were 29.5 day and 44.4/ vs. 41.2 day and 71.4/ for the C and S groups, respectively. We conclude that under range conditions, dietary supplementation of dromedary during late pregnancy stage and post-partum period improves productive and reproductive parameters.

  10. Effect on growth and reproduction of hormone immersed and masculinized fighting fish Betta splendens.

    Science.gov (United States)

    Kirankumar, Santhakumar; Pandian, Thavamani Jegajothivel

    2002-11-01

    To produce all-male progenies in the fighting fish, Betta splendens, six groups of fry were subjected to discrete immersion treatment at different 17alpha-methyltestosterone (MT) doses (viz. 100, 200, 500, 700, 900, and 1,000 microg/l) for a constant duration (3 hr/day) and frequency (second, fifth, and eighth day after hatching). The treatment at 900 microg/l led to 98% masculinization and 71% survival at sexual maturity. Treated groups, which showed significant deviation from the 1:1 sex ratio, were classified into two different series: S1 and S2. The groups that showed nearly cent-percent masculinization were classified as S1, and the other groups were classified as S2. The S1 males showed remarkably slower growth and attained 3.5 cm total length compared to 6.0 cm attained by a normal male. The S2 males attained 5.4 cm total length. Apart from these morphological defects, both S1 and S2 males suffered functional (decreased sperm count and sperm motility) and behavioral defects (incomplete embracing during mating) in their reproductive ability, leading to approximately 50% and 30% reduction in fecundity per mating, respectively. The cumulative fecundity loss suffered by the S1 male during its active reproductive phase is discussed. When normal and sex-reversed males were presented, a female preferred the former. Progeny testing of the sex-reversed males showed the occurrence of 12.75% males, indicating the possible role of autosomal genes in the sex determination mechanism of this species. Discrete immersion treatment at optimal/super-optimal doses ensured not only a higher percentage of masculinization, but also a higher frequency of homogametic males (XX). Copyright 2002 Wiley-Liss, Inc.

  11. Growth, puberty and reproduction in gilts born to dams deprived of nutrients during pregnancy.

    Science.gov (United States)

    Hard, D L; Anderson, L L

    1982-06-01

    Reproductive performance through two gestations was evaluated in a random selection of gilts born to dams deprived of nutrients or full-fed during pregnancy. After weaning, gilts born to dams previously subjected to inanition during the middle third or last third of gestation (O kcal/d; water only; 40 d), and those born to full-fed (7.028) kcal/d) control dams throughout gestation were raised in the same outdoor lot. At approximately 150 d of age, the gilts were observed for estrous behavior and mated at the third estrus. Age at puberal estrus was earlier (P less than .01) for gilts born to nutrient-deprived dams. Gilts from control dams exhibited first estrus at 250 d, whereas puberal estrus in gilts born to dams deprived of nutrients during the middle or last third of pregnancy occurred at 208 and 219 d, respectively. Fifteen of 18 mated gilts from the nutrient-deprived dams remained pregnant to term, compared with seven of eight gilts from control dams. Birth weights of first-parity living neonates from gilts born to nutrient-deprived dams were similar to those of newborns from controls. First-parity litter weights at birth also were similar for the experimental and control groups. Litter size at birth of first-parity living neonates averaged 7.9 piglets for gilts born to nutrient-deprived dams and was similar (P less than .05) to that for gilts from full-fed controls (9.4 piglets). Second-parity pregnancy rate, birth weight, litter weight and litter size at birth and weaning were similar for all gilts born to nutrient-deprived and control dams. These results indicate that brief segments of maternal nutrient deprivation during middle or late pregnancy have little detrimental effect on subsequent growth and reproduction of the female progeny in this litter-bearing species.

  12. WHAT IS ENDOGENOUS IN ENDOGENOUS GROWTH MODEL?

    OpenAIRE

    Öztürkler, Harun; Bozgeyik, Yusuf

    2014-01-01

    The neoclassical growth model predicts that as soon as technologic improvements and innovations are not provided the growth in per capita income would stop in long term. However, the long-run data for many countries indicate that positive rates of per capita income growth can persist over the long term. Growth theorists of the 1950s and 1960s recognized this modeling deficiency and usually patched it up by assuming that technological progress occurs in an exogenous manner. The endogenous grow...

  13. Complexities and contingencies conceptualised: towards a model of reproductive navigation.

    Science.gov (United States)

    van der Sijpt, Erica

    2014-02-01

    Current international attention to reproductive health behaviour is inspired by a western celebration of individual rights, autonomous action and rational choice. A predominant idea is that individuals should be free to act in accordance with their reproductive intentions and that, in doing so, they will attain their desired (and quantifiable) fertility outcomes. Yet such a framework leads to a misrepresentation of the reproductive dynamics on the ground, because individual fertility intentions are often not a priori defined, decisions are often not the result of rational calculation and reproductive happenings do not exist in a social vacuum. This article provides sociocultural evidence for a different conceptualisation of reproductive health behaviour. On the basis of long-term anthropological fieldwork in the East Province of Cameroon, I will analyse the complexities of fertility-related decision-making. Two case studies from the field will show that reproductive happenings are often characterised by indeterminacy and contingency. In order to understand the complex ways in which women give direction to these uncertainties, I propose an encompassing framework of reproductive navigation that explicitly acknowledges the influence of sociality and corporeality on fertility aspirations and actions. © 2013 The Author. Sociology of Health & Illness © 2013 Foundation for the Sociology of Health & Illness/John Wiley & Sons Ltd.

  14. Assisted Reproductive Technologies (ART) with Baboons Generate Live Offspring: A Nonhuman Primate Model for ART and Reproductive Sciences

    Science.gov (United States)

    Simerly, Calvin R.; Castro, Carlos A.; Jacoby, Ethan; Grund, Kevin; Turpin, Janet; McFarland, Dave; Champagne, Jamie; Jimenez, Joe B.; Frost, Pat; Bauer, Cassandra; Hewitson, Laura; Schatten, Gerald

    2012-01-01

    Human reproduction has benefited significantly by investigating non-human primate (NHP) models, especially rhesus macaques. To expand the Old World monkey species available for human reproductive studies, we present protocols in baboons, our closest Old World primate relatives, for Assisted Reproductive Technologies (ART) leading to live-born offspring. Baboons complement rhesus by confirming or modifying observations generated in humans often obtained by the study of clinically-discarded specimens donated by anonymous infertility patient-couples. Here, baboon ART protocols, including oocyte collection, in vitro fertilization, intracytoplasmic sperm injection (ICSI), preimplantation development to blastocyst stage and embryo transfer techniques are described. With baboon ART methodologies in place, motility during baboon fertilization was investigated by time-lapse video microscopy. The first ART baboons produced by ICSI, a pair of male twins, were delivered naturally at 165 days post-gestation. Genetic testing of these twins confirmed their ART parental origins and demonstrated that they are unrelated fraternal twins, not identicals. These results have implications for ART outcomes, embryonic stem cell derivation, and reproductive sciences. PMID:20631291

  15. Main and interactive effects of arsenic and selenium on mallard reproduction and duckling growth and survival

    Science.gov (United States)

    Stanley, T.R.; Spann, J.W.; Smith, G.J.; Rosscoe, R.

    1994-01-01

    Arsenic (As) and selenium (Se) occur together in high concentrations in the environment and can accumulate in aquatic plants and invertebrates consumed by waterfowl. Ninety-nine pairs of breeding mallards (Anas platyrhynchos) were fed diets supplemented with As (sodium arsenate) at 0, 25, 100, or 400 ug/g, in combination with Se (seleno-DL-methionine) at 0 or 10 ug/g, in a replicated factorial experiment. Ducklings produced were placed on the same treatment combination as their parents. Arsenic accumulated in adult liver and egg, reduced adult weight gain and liver weight, delayed the onset of egg laying, decreased whole egg weight, and caused eggshell thinning. Arsenic did not affect hatching success and was not teratogenic. In ducklings, As accumulated in the liver and reduced body weight, growth, and liver weight. Arsenic did not increase duckling mortality, but it did decrease overall duckling production. Selenium accumulated in adult liver and egg, was teratogenic, and decreased hatching success. Selenium did not affect adult weight, liver weight, survival, onset of egg laying, egg fertility, egg weight, or eggshell thickness. In ducklings, Se accumulated in the liver and reduced body weight and growth, and increased liver weight. Selenium increased duckling mortality and decreased overall duckling production. Antagonistic interactions between As and Se occurred whereby As reduced Se accumulation in liver and egg, and alleviated the effects of Se on hatching success and embryo deformities. It was demonstrated that As and Se, in the chemical forms and at the dietary levels administered in this study, can adversely affect mallard reproduction and duckling growth and survival, and that As can alleviate toxic effects of Se.

  16. Estimation of additive and dominance variance for reproductive traits from different models in Duroc purebred

    Directory of Open Access Journals (Sweden)

    Talerngsak Angkuraseranee

    2010-05-01

    Full Text Available The additive and dominance genetic variances of 5,801 Duroc reproductive and growth records were estimated usingBULPF90 PC-PACK. Estimates were obtained for number born alive (NBA, birth weight (BW, number weaned (NW, andweaning weight (WW. Data were analyzed using two mixed model equations. The first model included fixed effects andrandom effects identifying inbreeding depression, additive gene effect and permanent environments effects. The secondmodel was similar to the first model, but included the dominance genotypic effect. Heritability estimates of NBA, BW, NWand WW from the two models were 0.1558/0.1716, 0.1616/0.1737, 0.0372/0.0874 and 0.1584/0.1516 respectively. Proportionsof dominance effect to total phenotypic variance from the dominance model were 0.1024, 0.1625, 0.0470, and 0.1536 for NBA,BW, NW and WW respectively. Dominance effects were found to have sizable influence on the litter size traits analyzed.Therefore, genetic evaluation with the dominance model (Model 2 is found more appropriate than the animal model (Model 1.

  17. Lévy-based growth models

    DEFF Research Database (Denmark)

    Jónsdóttir, Kristjana Ýr; Schmiegel, Jürgen; Jensen, Eva Bjørn Vedel

    2008-01-01

    In the present paper, we give a condensed review, for the nonspecialist reader, of a new modelling framework for spatio-temporal processes, based on Lévy theory. We show the potential of the approach in stochastic geometry and spatial statistics by studying Lévy-based growth modelling of planar o...... objects. The growth models considered are spatio-temporal stochastic processes on the circle. As a by product, flexible new models for space–time covariance functions on the circle are provided. An application of the Lévy-based growth models to tumour growth is discussed....

  18. A universal model of ontogenetic growth

    Science.gov (United States)

    Martyushev, Leonid M.; Terentiev, Pavel S.

    2015-06-01

    The assumption that a single growth equation can be used to describe all biological objects on different organizational levels and a dimensional analysis are applied in order to substantiate universal model of ontogenetic growth. This model (the mass of a growing organism is a power function of time) is valid only in the initial period of growth. For the whole period of growth, a generalization of the model is advanced; it provides the same accuracy as previously known models of quantitative description of kinetic curves. Within the scope of the developed model, a number of interesting results related to allometry and biological time are obtained.

  19. Factors affecting cone production in Pinus pinaster Ait.: lack of growth-reproduction trade-offs but significant effects of climate and tree and stand characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, F.; Maguire, D.A.; González-Martínez, S.G.

    2017-11-01

    Aim of study: Our main goal is to determine the relationship between cone production and radial growth in Pinus pinaster Ait. under different climatic conditions across the Iberian Peninsula. Area of study: Coca Intensive Sampling Plateau, Northern Plateau (Spain). Material and methods: Cone counts were conducted on an intensive monitoring plot in Coca (North-Central Spain) during the years 2000, 2006 and 2007. A ZIP (zero-inflated Poisson) model was adjusted for simultaneously estimating the probability of obtaining crop cones and its amount. The Northern Atlantic Oscillation (NAO) index was used as explanatory variable, together with a wide variety of tree and local stand variables. Climate (as evaluated by NAO), local stand density (here estimated from the six nearest trees), tree size and vigor, competition and growth efficiency significantly influenced both occurrence and intensity of cone production. Main results: ZIP models for predicting reproductive effort seems an adequate tool to predict reproductive responses to climatic fluctuations and the resulting future species distribution in the face of climate change, as well as to identify silviculture actions that would promote reproductive success in naturally-regenerated stands, list and discuss relevant results (including numeric values of experimental results). Research highlights: Climate, stand density and tree conditions (size and vigor, competition and growth efficiency) influence significantly both cone occurrence and intensity of fruiting as shown by a ZIP model. As the climate variables included in the model (based on Northern Atlantic Oscillation, NAO) are general and easily obtained, the proposed model has practical applicability to predicting Pinus pinaster cone production in the Iberian Peninsula.

  20. Factors affecting cone production in Pinus pinaster Ait.: lack of growth-reproduction trade-offs but significant effects of climate and tree and stand characteristics

    Directory of Open Access Journals (Sweden)

    Felipe Bravo

    2017-10-01

    Full Text Available Aim of study: Our main goal is to determine the relationship between cone production and radial growth in Pinus pinaster Ait. under different climatic conditions across the Iberian Peninsula. Area of study: Coca Intensive Sampling Plateau, Northern Plateau (Spain. Material and methods: Cone counts were conducted on an intensive monitoring plot in Coca (North-Central Spain during the years 2000, 2006 and 2007. A ZIP (zero-inflated Poisson model was adjusted for simultaneously estimating the probability of obtaining crop cones and its amount. The Northern Atlantic Oscillation (NAO index was used as explanatory variable, together with a wide variety of tree and local stand variables. Climate (as evaluated by NAO, local stand density (here estimated from the six nearest trees, tree size and vigor, competition and growth efficiency significantly influenced both occurrence and intensity of cone production. Main results: ZIP models for predicting reproductive effort seems an adequate tool to predict reproductive responses to climatic fluctuations and the resulting future species distribution in the face of climate change, as well as to identify silviculture actions that would promote reproductive success in naturally-regenerated stands, list and discuss relevant results (including numeric values of experimental results. Research highlights: Climate, stand density and tree conditions (size and vigor, competition and growth efficiency influence significantly both cone occurrence and intensity of fruiting as shown by a ZIP model. As the climate variables included in the model (based on Northern Atlantic Oscillation, NAO are general and easily obtained, the proposed model has practical applicability to predicting Pinus pinaster cone production in the Iberian Peninsula.

  1. Water availability and population origin affect the expression of the tradeoff between reproduction and growth in Plantago coronopus

    DEFF Research Database (Denmark)

    Hansen, C. F.; Garcia, M. B.; Ehlers, B. K.

    2013-01-01

    temperature and precipitation. We found that water availability affected the expression of the tradeoff (both phenotypic and genetic) between reproduction and growth, being most accentuated under dry condition. However, populations responded very differently to water treatments. Plants from annual populations...... showed a similar response to drought condition with little variation among maternal families, suggesting a history of selection favouring genotypes with high allocation to reproduction when water availability is low. Plants from annual populations also expressed the highest level of plasticity...... water availability even among geographically close populations....

  2. Growth, mortality and reproduction of the blue tilapia Oreochromis aureus (Perciformes: Cichlidae in the Aguamilpa Reservoir, Mexico

    Directory of Open Access Journals (Sweden)

    Emilio Peña Messina

    2010-12-01

    Full Text Available Tilapia production has increased in Aguamilpa Reservoir, in Nayarit, Mexico, in the last few years and represents a good economic activity for rural communities and the country. We determined growth parameters, mortality and reproductive aspects for 2 413 specimens of blue tilapia Oreochromis aureus in this reservoir. Samples were taken monthly from July 2000 through June 2001, of which 1 371 were males and 1 042 were females. Standard length (SL and total weight (TW were measured in each organism. The SL/TW relationships through power models for sexes were determined. The growth parameters L ∞, k, and t0 of the von Bertalanffy equation were estimated using frequency distribution of length through ELEFAN-I computer program. Finally the reproductive cycle and size of first maturity were established using morph chromatic maturity scale. The results suggested that the males and females had negative allometric growth (bLos parámetros de crecimiento, reproducción y mortalidad de Oreochormis aureus en el embalse de Aguamilpa, México fueron determinados. Un total de 2 413 organismos se recolectaron entre julio de 2000 y junio de 2001, de los cuales 1 371 fueron machos y 1 042 hembras. Se analizó la relación longitud estándar (LE y peso total (PT mediante modelos potenciales. Los parámetros de crecimiento de la ecuación de von Bertalanffy fueron estimados usando la distribución de frecuencia de tallas con ayuda del programa ELEFAN-I. Finalmente se determinó el ciclo reproductivo, talla de primera madurez y fecundidad. Los resultados indicaron que tanto hembras como machos presentaron crecimiento alométrico negativo. Se encontraron diferencias significativas entre hembras y machos para la relación LE- PT sugiriendo modelos separados por sexo. No existieron diferencias significativas en el crecimiento por sexo y la tasa de explotación estimada (0.57/año sugiere que la pesquería durante el periodo de estudio mostró signos de

  3. Simulating the Reproductive Behavior of a Region’s Population with an Agent-Based Model

    Directory of Open Access Journals (Sweden)

    Valeriy Leonidovich Makarov

    2015-09-01

    Full Text Available The research analyses the impact of the inequality of demographic transition on socio-demographic characteristics of the regional population and on the dynamics of these characteristics. The study was conducted with the help of computer-based experiments (simulations, which was run on the original agent-based model. The model is an artificial society, and personal characteristics of its members are set so that they could represent age-demographic structure of a simulate region. The agents are divided into two subgroups, which differ in their reproductive strategy. The first group has traditional strategy with high birth rate. The second group has considerably lower birth rate, observed in the modern developed societies. The model uses stochastic approaches to imitate the principle processes of population growth: mortality and morbidity. Mortality is set according to age-sex specific mortality coefficients, which do not differ across the population as a whole. New agents (child births appear as a choice of agents – women of reproductive age, and the choice depends on the subgroup. The overall age and social structure of the region is aggregated across individual agents. A number of experiments has been carried out with the model utilization. This allowed forecasting the size and structure of the population of a given region. The results of the experiments have revealed that despite its simplicity, the developed agent-based model well predicts the initial conditions in the region (e.g. age-demographic and social structure. The model shows good fit in terms of estimating the dynamics of major characteristics of the population.

  4. Effects of Snail Density on Growth, Reproduction and Survival of Biomphalaria alexandrina Exposed to Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    T. D. Mangal

    2010-01-01

    Full Text Available The effects of snail density on Biomphalaria alexandrina parasitized with Schistosoma mansoni were investigated. Laboratory experiments were used to quantify the impact of high density on snail growth, fecundity, and survival. Density-dependent birth rates of snails were determined to inform mathematical models, which, until now, have assumed a linear relationship between density and fecundity. The experiments show that the rate of egg-laying followed a negative exponential distribution with increasing density and this was significantly affected by exposure to parasitic infection. High density also affected the weight of snails and survival to a greater degree than exposure to parasitic infection. Although snail growth rates were initially constrained by high density, they retained the potential for growth suggesting a reversible density-dependent mechanism. These experimental data can be used to parameterise models and confirm that snail populations are regulated by nonlinear density-dependent mechanisms.

  5. Modeling and mapping oak advance reproduction density using soil and site variables

    Science.gov (United States)

    John M. Kabrick; Jason L. Villwock; Daniel C. Dey; Tara L. Keyser; David R. Larsen

    2014-01-01

    Regenerating oaks (Quercus spp.) has remained a widespread and persistent problem throughout their natural range. Research shows that abundant oak advance reproduction is crucial for success. Although it is recognized that oak advance reproduction accumulation is inversely related to site quality, there has been little effort to model oak advance...

  6. Effect of Ocean acidification on growth, calcification and reproduction of calcifying and non-calcifying epibionts of brown algae

    Science.gov (United States)

    Saderne, V.; Wahl, M.

    2012-04-01

    Anthropogenic emissions of CO2 are leading to an acidification of the oceans of 0.4 pH units in the course of this century according to the more severe model scenarios. The excess of CO2 could notably affect the benthic communities of calcifiers and macrophytes in different aspects (photosynthesis, respiration and calcification). Seaweeds are one of the key species of nearshore benthic ecosystems of the Baltic Sea. They are the substratum of several fouling epibionts like bryozoans and tubeworms. Most of those species are bearing calcified structures and could therefore be potentially impacted by the seawater pCO2. On the other hand, the biological activity of the host may substantially modulate the pH and pCO2 conditions in the boundary layer where the epibionts live. The aim of the present study was to test the sensitivity of seaweed macrofouling communities to higher pCO2 concentration. Fragments of macroalgae Fucus serratus bearing the calcifiers Spirorbis spirorbis (Annelida) and Electra pilosa (Bryozoa) and the non-calcifier Alcyonidium gelatinosum (Bryozoa) were maintained for 30 days under three pCO2: natural 460 ± 59 µatm and enriched 1193 ± 166 µatm and 3150 ± 446 µatm. Our study showed a significant reduction of growth rates and reproduction of Spirorbis individuals at the highest pCO2. Tubeworms Juveniles exhibited enhanced calcification of 40 % when in the light compare to dark, presumably due to effect of photosynthetic and respiratory activities of the host alga. Electra colonies showed significantly improved growth rates at 1193 µatm. The overall net dissolution of the communities was significantly higher at 3150 µatm. No effect on Alcyonidium colonies growth rates was observed. Those results suggest a remarkable resistance of the algal macro-epibiontic communities to the most elevated pCO2 predicted for 2100 for open ocean (~1000 µatm) conditions. Concerns remains with regards to higher pCO2 possibly found in the future Baltic Sea.

  7. [Phenotypic plasticity and its regulation of tillers prolonged reproductive growth of Puccinellia tenuiflora population on alkalized meadow in Songnen Plains of China].

    Science.gov (United States)

    Sun, Ju; Yang, Yun-Fei

    2007-04-01

    Puccinellia tenuiflora is a salt-tolerant plant of grass family. By the method of random sampling, big samples of reproductive tillers of P. tenuiflora population on the alkalized meadow in the Songnen Plains of China were collected at early heading, heading, flowering, and milky stages, respectively, and the plasticity of their quantitative characters was analyzed. The results showed that except some fluctuations at flowering stage, the tiller height, tiller biomass, spike length and spike biomass of the reproductive tillers at other three growth stages increased significantly every five days with the increasing time of reproductive growth. At each growth stage, tiller height had a significant positive correlation with spike biomass, but a negative correlation with reproductive allocation. With the time of reproductive growth prolonged, the increasing rate of spike biomass at early heading, flowering and milky stages increased in power function with the increase of tiller height. The reproductive allocation decreased linearly by 43.2% and 44.31% at early heading and heading stages, respectively when the reproductive growth time increased ten days, and by 130% at milky stage when the time increased five days. The regulation of the tiller phenotypic plasticity of P. tenuiflora population at its reproductive growth stage followed definite patterns.

  8. Effects of reproduction on growth and survival in Atlantic cod, Gadus morhua, assessed by comparison to triploids

    DEFF Research Database (Denmark)

    Trippel, Edward A.; Butts, Ian; Babin, Amanda

    2014-01-01

    Despite increasing interest in optimal life history theory and the associated physiological, ecological and evolutionary processes, little information exists on gonad-soma tradeoffs and longevity of individuals over long time periods. We examined somatic and survival costs of reproduction...... in captive iteroparous, batch-spawning Atlantic cod (Gadus morhua), utilizing diploids and triploids, knowing that triploid females invest little to no energy into gametogenesis. Based on annual specific growth rate, there was no evidence for a somatic cost of reproduction at ages 2 (virgin year) and 4...... spanned nearly four years. Although previously done for bivalves, to our knowledge, this is the first time the cost of reproduction has been evaluated using triploid fish as a comparator...

  9. Glycosylation of inositol phosphorylceramide sphingolipids is required for normal growth and reproduction in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Tartaglio, Virginia [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Rennie, Emilie A. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Univ. of Nebraska, Lincoln, NE (United States). Center for Plant Science Innovation and Dept. of Biochemistry; Cahoon, Rebecca [Univ. of Nebraska, Lincoln, NE (United States). Center for Plant Science Innovation and Dept. of Biochemistry; Wang, George [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Baidoo, Edward [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Mortimer, Jennifer C. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Cahoon, Edgar B. [Univ. of Nebraska, Lincoln, NE (United States). Center for Plant Science Innovation and Dept. of Biochemistry; Scheller, Henrik V. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Biological Systems and Engineering Division; Univ. of California, Berkeley, CA (United States). Dept. of Plant and Microbial Biology

    2016-09-19

    Sphingolipids are a major component of plant plasma membranes and endomembranes, and mediate a diverse range of biological processes. Study of the highly glycosylated glycosyl inositol phosphorylceramide (GIPC) sphingolipids has been slow as a result of challenges associated with the extractability of GIPCs, and their functions in the plant remain poorly characterized. We recently discovered an Arabidopsis GIPC glucuronosyltransferase, INOSITOL PHOSPHORYLCERAMIDE GLUCURONOSYLTRANSFERASE 1 (IPUT1), which is the first enzyme in the GIPC glycosylation pathway. Plants homozygous for the iput1 loss-of-function mutation were unobtainable, and so the developmental effects of reduced GIPC glucuronosylation could not be analyzed in planta. Using a pollen-specific rescue construct, we have here isolated homozygous iput1 mutants. The iput1 mutants show severe dwarfism, compromised pollen tube guidance, and constitutive activation of salicyclic acid-mediated defense pathways. The mutants also possess reduced GIPCs, increased ceramides, and an increased incorporation of short-chain fatty acids and dihydroxylated bases into inositol phosphorylceramides and GIPCs. The assignment of a direct role for GIPC glycan head groups in the impaired processes in iput1 mutants is complicated by the vast compensatory changes in the sphingolipidome; however, our results reveal that the glycosylation steps of GIPC biosynthesis are important regulated components of sphingolipid metabolism. In conclusion, this study corroborates previously suggested roles for GIPC glycans in plant growth and defense, suggests important role s for them in reproduction and demonstrates that the entire sphingolipidome is sensitive to their status.

  10. Effects of melatonin implantation on cashmere yield, fibre characteristics, duration of cashmere growth as well as growth and reproductive performance of Inner Mongolian cashmere goats.

    Science.gov (United States)

    Duan, Chunhui; Xu, Jianhai; Sun, Changmian; Jia, Zhihai; Zhang, Wei

    2015-01-01

    Exogenous melatonin could induce cashmere growth. However, induced growth of cashmere fleece by melatonin implants cannot be combined with the typical growth, resulting in earlier shedding followed by another cycle of cashmere growth. To address this issue, we examine the effects on the cashmere yield, fibre characteristics, and the growth and reproductive performance of cashmere goats of planned administration of melatonin. Eighteen half-sib, female goats were assigned to two treatments (n = 9) including a control and a treatment where melatonin (2 mg/kg BW) was implanted at the end of April and end of June. Cashmere growth and shedding were observed for approximately 1 year following implantation. Fibre samples were collected monthly to determine cumulative cashmere length. Initiation and cessation dates for cashmere growth as well as the rate of cashmere growth were calculated. Cashmere yield, weight gain of dam, kidding date, litter size, and birth weight were also recorded. Melatonin implantation increased cashmere yield by 34.5 % (control 553.7 g vs. melatonin 745.0 g; P cashmere length by 21.3 % (control 95.2 mm vs. melatonin 115.4 mm; P cashmere growth was longer in melatonin-treated goats than in control goats (307 vs.270 days; P cashmere yield by combining the induced growth of cashmere fleece with the typical growth and decreased the fibre diameter without changing dam growth rate or reproductive performance.

  11. Exogenous applications of plant growth regulators influence the reproductive growth of citrus sinensis osbeck cv. blood red

    International Nuclear Information System (INIS)

    Khan, A.S.; Malik, A.U.; Ahmad, S.; Ahmad, I.

    2014-01-01

    To study the influence of exogenous applications of plant growth regulators on the reproductive behaviour of low bearing sweet orange (Citrus sinensis Osbeck) trees, three separate experiments were conducted on twelve years old 'Blood Red' Sweet orange trees budded on Rough Lemon (Citrus jambheri L.) root stock. In the first experiment, trees were sprayed with 20 mg L-1 2, 4-D and GA3 alone or in combination at mid bloom (MB) stage, whilst in the second and third experiments 20 mg L-1 2, 4-D and GA3 alone or in combination were sprayed at MB + 6 weeks after MB, and at MB + 22 and 28 weeks after MB stages, respectively. A single tree was selected as an experimental unit and each treatment was replicated four times. Data regarding the flowering intensity, flower drop, fruit set, fruit drop and fruit harvest percentages (%) were collected and analyzed statistically. In all experiments exogenous application of 20 mg L-1 2, 4-D and GA3 alone or in combination to Blood Red sweet orange trees reduced the flower drop % and increased the fruit set % as compared to untreated trees. Application 2, 4-D and GA3 alone or in combination at MB did not affect the fruit drop % and fruit harvest % in contrast to untreated trees. The trees sprayed with 20 mg L-1 GA3 alone or in combination with 2, 4-D at MB + 22 and 28 weeks after MB exhibited highest reduction in the fruit drop % compared to control trees. In conclusions application GA3 (20 mg L-1) alone or in combination of 2, 4-D (20 mg L-1) at MB + 22 and 28 weeks after MB can be used effectively to increase the fruit set and reduce the fruit drop in Blood Red sweet oranges. (author)

  12. Trajectories and models of individual growth

    Directory of Open Access Journals (Sweden)

    Arseniy Karkach

    2006-11-01

    Full Text Available It has long been recognized that the patterns of growth play an important role in the evolution of age trajectories of fertility and mortality (Williams, 1957. Life history studies would benefit from a better understanding of strategies and mechanisms of growth, but still no comparative research on individual growth strategies has been conducted. Growth patterns and methods have been shaped by evolution and a great variety of them are observed. Two distinct patterns - determinate and indeterminate growth - are of a special interest for these studies since they present qualitatively different outcomes of evolution. We attempt to draw together studies covering growth in plant and animal species across a wide range of phyla focusing primarily on the noted qualitative features. We also review mathematical descriptions of growth, namely empirical growth curves and growth models, and discuss the directions of future research.

  13. QSAR models for reproductive toxicity and endocrine disruption in regulatory use – a preliminary investigation

    DEFF Research Database (Denmark)

    Jensen, Gunde Egeskov; Niemelä, Jay Russell; Wedebye, Eva Bay

    2008-01-01

    the new legislation. This article focuses on a screening exercise by use of our own and commercial QSAR models for identification of possible reproductive toxicants. Three QSAR models were used for reproductive toxicity for the endpoints teratogenic risk to humans (based on animal tests, clinical data...... for humans owing to possible developmental toxic effects: Xn (Harmful) and R63 (Possible risk of harm to the unborn child). The chemicals were also screened in three models for endocrine disruption....

  14. Using social parasitism to test reproductive skew models in a primitively eusocial wasp.

    Science.gov (United States)

    Green, Jonathan P; Cant, Michael A; Field, Jeremy

    2014-08-22

    Remarkable variation exists in the distribution of reproduction (skew) among members of cooperatively breeding groups, both within and between species. Reproductive skew theory has provided an important framework for understanding this variation. In the primitively eusocial Hymenoptera, two models have been routinely tested: concessions models, which assume complete control of reproduction by a dominant individual, and tug-of-war models, which assume on-going competition among group members over reproduction. Current data provide little support for either model, but uncertainty about the ability of individuals to detect genetic relatedness and difficulties in identifying traits conferring competitive ability mean that the relative importance of concessions versus tug-of-war remains unresolved. Here, we suggest that the use of social parasitism to generate meaningful variation in key social variables represents a valuable opportunity to explore the mechanisms underpinning reproductive skew within the social Hymenoptera. We present a direct test of concessions and tug-of-war models in the paper wasp Polistes dominulus by exploiting pronounced changes in relatedness and power structures that occur following replacement of the dominant by a congeneric social parasite. Comparisons of skew in parasitized and unparasitized colonies are consistent with a tug-of-war over reproduction within P. dominulus groups, but provide no evidence for reproductive concessions.

  15. Influence of reproduction traits and pre-weaning growth rate on herd ...

    African Journals Online (AJOL)

    The reproduction and calf survival rates were the most important production traits that affected herd efficiency. Management practices should be adapted to maximize the reproduction rate of the females, including the young heifers, to maximise herd efficiency. South African Journal of Animal Science Vol. 36(2) 2006: 89-98 ...

  16. Shortleaf pine reproduction abundance and growth in pine-oak stands in the Missouri Ozarks

    Science.gov (United States)

    Elizabeth M. Blizzard; Doyle Henken; John M. Kabrick; Daniel C. Dey; David R. Larsen; David Gwaze

    2007-01-01

    We conducted an operational study to evaluate effect of site preparation treatments on pine reproduction density and the impact of overstory basal area and understory density on pine reproduction height and basal diameter in pine-oak stands in the Missouri Ozarks. Stands were harvested to or below B-level stocking, but patchiness of the oak decline lead to some plots...

  17. Birth weight, intrauterine growth retardation and fetal susceptibility to porcine reproductive and respiratory syndrome virus

    Science.gov (United States)

    The severity of porcine reproductive and respiratory syndrome was compared in pregnant gilts originating from high and low birth weight litters. One-hundred and eleven pregnant gilts experimentally infected with porcine reproductive and respiratory syndrome virus on gestation day 85 (±1) were necrop...

  18. Growth and reproduction of the sea snake, Emydocephalus ijimae, in the central Ryukyus, Japan: a mark and recapture study.

    Science.gov (United States)

    Masunaga, Gen; Ota, Hidetoshi

    2003-04-01

    A mark and recapture study was carried out for three years on a population of the Ijima's sea snake, Emydocephalus ijimae, in the coastal shallow water of Zamamijima Island, central Ryukyus, Japan. The relatively high recapture (47% of 167 marked snakes) suggests that E. ijimae is a particularly philopatric, sedentary species among the sea snakes. The sex ratio (male: female), approximately 1.6:1, significantly skewed from 1:1. The growth rate in SVL declined with growth, with females thoroughly growing better than males. Males and females were estimated to begin reproductive activity in the second or third summer and the third spring after birth, respectively. Frequency of female reproduction is guessed to vary from annual to biennial, or even less frequent.

  19. Modeling Tissue Growth Within Nonwoven Scaffolds Pores

    Science.gov (United States)

    Church, Jeffrey S.; Alexander, David L.J.; Russell, Stephen J.; Ingham, Eileen; Ramshaw, John A.M.; Werkmeister, Jerome A.

    2011-01-01

    In this study we present a novel approach for predicting tissue growth within the pores of fibrous tissue engineering scaffolds. Thin nonwoven polyethylene terephthalate scaffolds were prepared to characterize tissue growth within scaffold pores, by mouse NR6 fibroblast cells. On the basis of measurements of tissue lengths at fiber crossovers and along fiber segments, mathematical models were determined during the proliferative phase of cell growth. Tissue growth at fiber crossovers decreased with increasing interfiber angle, with exponential relationships determined on day 6 and 10 of culture. Analysis of tissue growth along fiber segments determined two growth profiles, one with enhanced growth as a result of increased tissue lengths near the fiber crossover, achieved in the latter stage of culture. Derived mathematical models were used in the development of a software program to visualize predicted tissue growth within a pore. This study identifies key pore parameters that contribute toward tissue growth, and suggests models for predicting this growth, based on fibroblast cells. Such models may be used in aiding scaffold design, for optimum pore infiltration during the tissue engineering process. PMID:20687775

  20. ON MODELING METHODS OF REPRODUCTION OF FIXED ASSETS IN DYNAMIC INPUT - OUTPUT MODELS

    Directory of Open Access Journals (Sweden)

    Baranov A. O.

    2014-12-01

    Full Text Available The article presents a comparative study of methods for modeling reproduction of fixed assets in various types of dynamic input-output models, which have been developed at the Novosibirsk State University and at the Institute of Economics and Industrial Engineering of the Siberian Division of Russian Academy of Sciences. The study compares the technique of information providing for the investment blocks of the models. Considered in detail mathematical description of the block of fixed assets reproduction in the Dynamic Input - Output Model included in the KAMIN system and the optimization interregional input - output model. Analyzes the peculiarities of information support of investment and fixed assets blocks of the Dynamic Input - Output Model included in the KAMIN system and the optimization interregional input - output model. In conclusion of the article provides suggestions for joint use of the analyzed models for Russian economy development forecasting. Provided the use of the KAMIN system’s models for short-term and middle-term forecasting and the optimization interregional input - output model to develop long-term forecasts based on the spatial structure of the economy.

  1. A model of northern pintail productivity and population growth rate

    Science.gov (United States)

    Flint, Paul L.; Grand, James B.; Rockwell, Robert F.

    1998-01-01

    Our objective was to synthesize individual components of reproductive ecology into a single estimate of productivity and to assess the relative effects of survival and productivity on population dynamics. We used information on nesting ecology, renesting potential, and duckling survival of northern pintails (Anas acuta) collected on the Yukon-Kuskokwim Delta (Y-K Delta), Alaska, 1991-95, to model the number of ducklings produced under a range of nest success and duckling survival probabilities. Using average values of 25% nest success, 11% duckling survival, and 56% renesting probability from our study population, we calculated that all young in our population were produced by 13% of the breeding females, and that early-nesting females produced more young than later-nesting females. Further, we calculated, on average, that each female produced only 0.16 young females/nesting season. We combined these results with estimates of first-year and adult survival to examine the growth rate (X) of the population and the relative contributions of these demographic parameters to that growth rate. Contrary to aerial survey data, the population projection model suggests our study population is declining rapidly (X = 0.6969). The relative effects on population growth rate were 0.1175 for reproductive success, 0.1175 for first-year survival, and 0.8825 for adult survival. Adult survival had the greatest influence on X for our population, and this conclusion was robust over a range of survival and productivity estimates. Given published estimates of annual survival for adult females (61%), our model suggested nest success and duckling survival need to increase to approximately 40% to achieve population stability. We discuss reasons for the apparent discrepancy in population trends between our model and aerial surveys in terms of bias in productivity and survival estimates.

  2. Effect of temperature on growth, mortality, reproduction, and production of adult Lymnaea obrussa Say (Mollusca:Gastropoda)

    International Nuclear Information System (INIS)

    Mattice, J.S.

    1975-01-01

    Shell lengths and egg production were measured weekly under constant (K; 10, 15, 20, 25 0 C) and varying temperature regimes during the reproductive period. Varying regimes included natural field temperature in a pond (F; diurnal and seasonal), mean daily field temperature (anti F; seasonal) and 5 and 10 0 C above anti F. Growth rate of large snails (>10 mm) was unaffected by temperature, but small snails (6 to 10 mm) grew fastest at 15 0 C(K). Growth and reproductive periods were longest, production was highest, and mortality rate was lowest at 15 0 C(K). Rate (per snail) of egg production increased with temperature. At equal mean temperature, regime affected growth rate only at anti F. Regime affected the following values as shown: mortality rate,F > anti F = K; rate of reproduction, F > K > anti F; and total production, K > anti F = F. The validity of extrapolation of energetic data from laboratory to field is discussed. Data relating production and temperature are valuable in thermal impact analysis. (U.S.)

  3. Environmental influences on kelp performance across the reproductive period: an ecological trade-off between gametophyte survival and growth?

    Science.gov (United States)

    Mohring, Margaret B; Kendrick, Gary A; Wernberg, Thomas; Rule, Michael J; Vanderklift, Mathew A

    2013-01-01

    Most kelps (order Laminariales) exhibit distinct temporal patterns in zoospore production, gametogenesis and gametophyte reproduction. Natural fluctuations in ambient environmental conditions influence the intrinsic characteristics of gametes, which define their ability to tolerate varied conditions. The aim of this work was to document seasonal patterns in reproduction and gametophyte growth and survival of Ecklonia radiata (C. Agardh) J. Agardh in south-western Australia. These results were related to patterns in local environmental conditions in an attempt to ascertain which factors explain variation throughout the season. E. radiata was fertile (produced zoospores) for three and a half months over summer and autumn. Every two weeks during this time, gametophytes were grown in a range of temperatures (16-22 °C) in the laboratory. Zoospore densities were highly variable among sample periods; however, zoospores released early in the season produced gametophytes which had greater rates of growth and survival, and these rates declined towards the end of the reproductive season. Growth rates of gametophytes were positively related to day length, with the fastest growing recruits released when the days were longest. Gametophytes consistently survived best in the lowest temperature (16 °C), yet exhibited optimum growth in higher culture temperatures (20-22 °C). These results suggest that E. radiata releases gametes when conditions are favourable for growth, and E. radiata gametophytes are tolerant of the range of temperatures observed at this location. E. radiata releases the healthiest gametophytes when day length and temperature conditions are optimal for better germination, growth, and sporophyte production, perhaps as a mechanism to help compete against other species for space and other resources.

  4. Complexities and contingencies conceptualized: towards a model of reproductive navigation

    NARCIS (Netherlands)

    van der Sijpt, E.; Cohn, S.

    2014-01-01

    This chapter provides sociocultural evidence for a different conceptualization of reproductive health behaviour. On the basis of long-term anthropological fieldwork in the East Province of Cameroon the author analyses of the social complexities and contingencies of local fertility-related decisions

  5. Water availability and population origin affect the expression of the tradeoff between reproduction and growth in Plantago coronopus.

    Science.gov (United States)

    Hansen, C F; García, M B; Ehlers, B K

    2013-05-01

    Investment in reproduction and growth represent a classic tradeoff with implication for life history evolution. The local environment can play a major role in the magnitude and evolutionary consequences of such a tradeoff. Here, we examined the investment in reproductive and vegetative tissue in 40 maternal half-sib families from four different populations of the herb Plantago coronopus growing in either a dry or wet greenhouse environment. Plants originated from populations with an annual or a perennial life form, with annuals prevailing in drier habitats with greater seasonal variation in both temperature and precipitation. We found that water availability affected the expression of the tradeoff (both phenotypic and genetic) between reproduction and growth, being most accentuated under dry condition. However, populations responded very differently to water treatments. Plants from annual populations showed a similar response to drought condition with little variation among maternal families, suggesting a history of selection favouring genotypes with high allocation to reproduction when water availability is low. Plants from annual populations also expressed the highest level of plasticity. For the perennial populations, one showed a large variation among maternal families in resource allocation and expressed significant negative genetic correlations between reproductive and vegetative biomass under drought. The other perennial population showed less variation in response to treatment and had trait values similar to those of the annuals, although it was significantly less plastic. We stress the importance of considering intraspecific variation in response to environmental change such as drought, as conspecific plants exhibited very different abilities and strategies to respond to high versus low water availability even among geographically close populations. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

  6. Possible Associations between Bovine Growth Hormone Gene Polymorphism and Reproductive Traits

    Directory of Open Access Journals (Sweden)

    Maria Marina Unanian

    2002-09-01

    Full Text Available The polymorphism of the bovine growth hormone gene (bGH was studied in 211 Nellore pure breed males for association with reproductive traits. Scrotal circumference and testosterone concentrations were collected monthly from 10 until 16 months of age. Additionally, testicular growth rates were calculated. DNA was amplified by PCR and digested using Msp I and Hae III restriction enzymes. Every polymorphism presented two alleles. The predominant alleles were D (0.85 and F (0.98, respectively, and genotype EE - bGH/Hae III was missing. Significant association (PEm 211 machos da raça Nelore, PO, foi estudada a associação entre os polimorfismos do gene do hormônio de crescimento bovino (bGH e características reprodutivas. Para o estudo foram realizadas medições mensais da circunferência escrotal e concentração de testosterona dos 10 aos 16 meses de idade e, ainda foi calculada a taxa de crescimento testicular. O DNA foi amplificado por PCR e digerido com as enzimas de restrição Msp I e Hae III. Cada um dos polimorfismos obtidos apresentou dois alelos. Os aleleo D (0,85 e F (0,98 predominaram na população estudada. Não foram encontrados animais portadores do genótipo EE do polimorfismo bGH/Hae III. Houve associação significativa (P<0,05 entre o polimorfismo bGH/Msp I, a circunferência escrotal e o crescimento testicular após a puberdade e, ainda, entre o polimorfismo do bGH/Hae III e a concentração da testosterona na puberdade. Os resultados sugerem que os polimorfismos bGH/Msp I e bGH/Hae III poderiam ser considerados marcadores do desenvolvimento testicular e o aparecimento da puberdade. Pela importância das observações, em função do reduzido tamanho da amostra, os estudos devem prosseguir.

  7. Estimation and computation of the growth rate in Leslie's and Lotka's population models.

    Science.gov (United States)

    Anderson, D H

    1975-09-01

    Leslie's or Lotka's population model has a rate of natural increase (lambda or r) which represents the growth rate of the population and characterizes the ability of the population to attain a stable age distribution. In this article are presented upper and lower bounds on that rate, primarily in terms of the net reproduction rate and other commonly used parameters of the population. Also a discussion is given of quadratically convergent numerical iterative methods of computing the growth rate.

  8. Individual growth and reproductive behavior in a newly established population of northern snakehead (Channa argus), Potomac River, USA

    Science.gov (United States)

    Landis, Andrew M. Gascho; Lapointe, Nicolas W. R.; Angermeier, Paul L.

    2010-01-01

    Northern snakehead (Channa argus) were first found in the Potomac River in 2004. In 2007, we documented feeding and reproductive behavior to better understand how this species is performing in this novel environment. From April to October, we used electrofishing surveys to collect data on growth, condition, and gonad weight of adult fish. Growth rates of young were measured on a daily basis for several weeks. Mean length-at-age for Potomac River northern snakehead was lower than for fish from China, Russia, and Uzbekistan. Fish condition was above average during spring and fall, but below average in summer. Below-average condition corresponded to periods of high spawning activity. Gonadosomatic index indicated that females began spawning at the end of April and continued through August. Peak spawning occurred at the beginning of June when average temperatures reached 26°C. Larval fish growth rate, after the transition to exogenous feeding, was 2.3 (SD ± 0.7) mm (total length, TL) per day. Although Potomac River northern snakehead exhibited lower overall growth rates when compared to other populations, these fish demonstrated plasticity in timing of reproduction and rapid larval growth rates. Such life history characteristics likely contribute to the success of northern snakehead in its new environment and limit managers’ options for significant control of its invasion.

  9. Growth curve models and statistical diagnostics

    CERN Document Server

    Pan, Jian-Xin

    2002-01-01

    Growth-curve models are generalized multivariate analysis-of-variance models. These models are especially useful for investigating growth problems on short times in economics, biology, medical research, and epidemiology. This book systematically introduces the theory of the GCM with particular emphasis on their multivariate statistical diagnostics, which are based mainly on recent developments made by the authors and their collaborators. The authors provide complete proofs of theorems as well as practical data sets and MATLAB code.

  10. On a Versatile Stochastic Growth Model

    Directory of Open Access Journals (Sweden)

    Samiur Arif

    2012-06-01

    Full Text Available Growth phenomena are ubiquitous and pervasive not only in biology and the medical sciences, but also in economics, marketing and the computer and social sciences. We introduce a three-parameter version of the classic pure-birth process growth model when suitably instantiated, can be used to model growth phenomena in many seemingly unrelated application domains. We point out that the model is computationally attractive since it admits of conceptually simple, closed form solutions for the time-dependent probabilities.

  11. The neuropeptide schistosomin and haemolymph from parasitized snails induce similar changes in excitability in neuroendocrine cells controlling reproduction and growth in a freshwater snail

    NARCIS (Netherlands)

    Hordijk, P. L.; de Jong-Brink, M.; ter Maat, A.; Pieneman, A. W.; Lodder, J. C.; Kits, K. S.

    1992-01-01

    Infection of the snail Lymnaea stagnalis with the schistosome parasite Trichobilharzia ocellata results in inhibition of reproduction and in giant growth. Parasite-related effects on the neuroendocrine centres that control these processes were studied electrophysiologically. Haemolymph from infected

  12. [Characteristics of Stipa grandis growth and reproductive biomass allocation at different hill position of Xilingol grassland, Inner Mongolia].

    Science.gov (United States)

    Gao, Hui; Gao, Yu-bao; Liu, Hai-ying; Liu, Jing-ling

    2009-09-01

    An investigation was conducted on the vegetative and reproductive biomass allocation of Stipa grandis at the hill-top and hill-foot of Xilingol grassland, and relatedness- and factor analyses were made to study the effects of hill position on the S. grandis seed biomass. Significant differences were observed in the vegetative and reproductive growth of S. grandis plants at the hill-top and hill-foot. At hill-foot, the height and number of non-flowering S. grandis ramets increased by 24.69% and 35.37%, respectively, the number of flowering ramets increased by 102.97%, the vegetative, reproductive, and total biomass increased by 44.14%, 95.59% and 47.45%, respectively, and the 100-grain mass increased by 25.00%, as compared with those at hill-top. The seed biomass of S. grandis at hill-top was mainly affected by soil moisture content, while that at hill-foot was mainly affected by soil pH. Hill position induced the differentiation of soil moisture and N contents, and made the S. grandis at the fertile hill-foot allocating more energy to its sexual reproduction.

  13. Food Legumes and Rising Temperatures: Effects, Adaptive Functional Mechanisms Specific to Reproductive Growth Stage and Strategies to Improve Heat Tolerance

    Directory of Open Access Journals (Sweden)

    Kumari Sita

    2017-10-01

    Full Text Available Ambient temperatures are predicted to rise in the future owing to several reasons associated with global climate changes. These temperature increases can result in heat stress- a severe threat to crop production in most countries. Legumes are well-known for their impact on agricultural sustainability as well as their nutritional and health benefits. Heat stress imposes challenges for legume crops and has deleterious effects on the morphology, physiology, and reproductive growth of plants. High-temperature stress at the time of the reproductive stage is becoming a severe limitation for production of grain legumes as their cultivation expands to warmer environments and temperature variability increases due to climate change. The reproductive period is vital in the life cycle of all plants and is susceptible to high-temperature stress as various metabolic processes are adversely impacted during this phase, which reduces crop yield. Food legumes exposed to high-temperature stress during reproduction show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to smaller seeds and poor yields. Through various breeding techniques, heat tolerance in major legumes can be enhanced to improve performance in the field. Omics approaches unravel different mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward high-temperature stress.

  14. Survival, reproduction, growth, and parasite resistance of aquatic organisms exposed on-site to wastewater treated by advanced treatment processes.

    Science.gov (United States)

    Schlüter-Vorberg, Lisa; Knopp, Gregor; Cornel, Peter; Ternes, Thomas; Coors, Anja

    2017-05-01

    Advanced wastewater treatment technologies are generally known to be an effective tool for reducing micropollutant discharge into the aquatic environment. Nevertheless, some processes such as ozonation result in stable transformation products with often unknown toxicity. In the present study, whole effluents originating from nine different steps of advanced treatment combinations were compared for their aquatic toxicity. Assessed endpoints were survival, growth and reproduction of Lumbriculus variegatus, Daphnia magna and Lemna minor chronically exposed in on-site flow-through tests based on standard guidelines. The treatment combinations were activated sludge treatment followed by ozonation with subsequent filtration by granular activated carbon or biofilters and membrane bioreactor treatment of raw wastewater followed by ozonation. Additionally, the impact of treated wastewater on the immune response of invertebrates was investigated by challenging D. magna with a bacterial endoparasite. Conventionally treated wastewater reduced reproduction of L. variegatus by up to 46%, but did not affect D. magna and L. minor with regard to survival, growth, reproduction and parasite resistance. Instead, parasite susceptibility was significantly reduced in D. magna exposed to conventionally treated as well as ozonated wastewater in comparison to D. magna exposed to the medium control. None of the three test organisms provided clear evidence that wastewater ozonation leads to increased aquatic toxicity. Rather than to the presence of toxic transformation products, the affected performance of L. variegatus could be linked to elevated concentrations of ammonium and nitrite that likely resulted from treatment failures. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Growth models with internal competition

    International Nuclear Information System (INIS)

    Ausloos, M.; Vandewalle, N.

    1996-01-01

    Combined statistical physics and computation modelling give new instruments for the study of non-equilibrium systems. We briefly review generalized Eden and Diffusion-Limited Aggregation models as applied to spreading phenomena. We indicate the occurrence of non-universal behaviors. (author)

  16. Long-term hyperphagia and caloric restriction caused by low- or high-density husbandry have differential effects on zebrafish postembryonic development, somatic growth, fat accumulation and reproduction.

    Directory of Open Access Journals (Sweden)

    Sandra Leibold

    Full Text Available In recent years, the zebrafish (Danio rerio has emerged as an alternative vertebrate model for energy homeostasis and metabolic diseases, including obesity and anorexia. It has been shown that diet-induced obesity (DIO in zebrafish shares multiple pathophysiological features with obesity in mammals. However, a systematic and comprehensive analysis of the different pathways of energy expenditure in obese and starved fish had been missing thus far. Here, we carry out long-term ad libitum feeding (hyperphagia and caloric restriction studies induced by low- or high-density husbandry, respectively, to investigate the impact of caloric intake on the timing of scale formation, a crucial step of postembryonic development and metamorphosis, and on somatic growth, body weight, fat storage and female reproduction. We show that all of them are positively affected by increased caloric intake, that middle-aged fish develop severe DIO, and that the body mass index (BMI displays a strict linear correlation with whole-body triglyceride levels in adult zebrafish. Interestingly, juvenile fish are largely resistant to DIO, while BMI and triglyceride values drop in aged fish, pointing to aging-associated anorexic effects. Histological analyses further indicate that increased fat storage in white adipose tissue involves both hyperplasia and hypertrophy of adipocytes. Furthermore, in ovaries, caloric intake primarily affects the rate of oocyte growth, rather than total oocyte numbers. Finally, comparing the different pathways of energy expenditure with each other, we demonstrate that they are differentially affected by caloric restriction / high-density husbandry. In juvenile fish, scale formation is prioritized over somatic growth, while in sexually mature adults, female reproduction is prioritized over somatic growth, and somatic growth over fat storage. Our data will serve as a template for future functional studies to dissect the neuroendocrine regulators of

  17. Novel metrics for growth model selection.

    Science.gov (United States)

    Grigsby, Matthew R; Di, Junrui; Leroux, Andrew; Zipunnikov, Vadim; Xiao, Luo; Crainiceanu, Ciprian; Checkley, William

    2018-01-01

    Literature surrounding the statistical modeling of childhood growth data involves a diverse set of potential models from which investigators can choose. However, the lack of a comprehensive framework for comparing non-nested models leads to difficulty in assessing model performance. This paper proposes a framework for comparing non-nested growth models using novel metrics of predictive accuracy based on modifications of the mean squared error criteria. Three metrics were created: normalized, age-adjusted, and weighted mean squared error (MSE). Predictive performance metrics were used to compare linear mixed effects models and functional regression models. Prediction accuracy was assessed by partitioning the observed data into training and test datasets. This partitioning was constructed to assess prediction accuracy for backward (i.e., early growth), forward (i.e., late growth), in-range, and on new-individuals. Analyses were done with height measurements from 215 Peruvian children with data spanning from near birth to 2 years of age. Functional models outperformed linear mixed effects models in all scenarios tested. In particular, prediction errors for functional concurrent regression (FCR) and functional principal component analysis models were approximately 6% lower when compared to linear mixed effects models. When we weighted subject-specific MSEs according to subject-specific growth rates during infancy, we found that FCR was the best performer in all scenarios. With this novel approach, we can quantitatively compare non-nested models and weight subgroups of interest to select the best performing growth model for a particular application or problem at hand.

  18. Cost of reproduction in the Queensland fruit fly: Y-model versus lethal protein hypothesis

    OpenAIRE

    Fanson, Benjamin G.; Fanson, Kerry V.; Taylor, Phillip W.

    2012-01-01

    The trade-off between lifespan and reproduction is commonly explained by differential allocation of limited resources. Recent research has shown that the ratio of protein to carbohydrate (P : C) of a fly's diet mediates the lifespan–reproduction trade-off, with higher P : C diets increasing egg production but decreasing lifespan. To test whether this P : C effect is because of changing allocation strategies (Y-model hypothesis) or detrimental effects of protein ingestion on lifespan (lethal p...

  19. Role of plants in the vegetative and reproductive growth of saprobic basidiomycetous ground fungi.

    Science.gov (United States)

    Gramss, Gerhard; Bergmann, Hans

    2008-11-01

    Non-symbiotic microorganisms engineered or expensively selected to degrade xenobiotic hydrocarbons or modify heavy-metal uptake of plants in soil remediations die back after their introduction into the target soils. Mycelia of saprobic basidiomycetes were therefore inoculated into soil samples of 1 l in glass vessels to record mycelial growth and reproduction in the immediate rhizosphere of up to 11 herbaceous plant species, or to study their responses to the separate volatiles from whole plant swards or their root balls whose emanations had been collected in 1.5-l plastic bags fixed to the glass vessels. Excess CO2 was controlled with NaOH solution. Volatiles from root balls of parsley and pea but not wheat, from unplanted soils, from the fungus-permeated, unplanted substrate soil itself, and from the rooting soil of whole wheat sward increased mycelial densities in Clitocybe sp. more than in Agaricus macrocarpus and indicated thus a higher nutrient state of the mycelia. Organic volatiles proved therefore to be a significant carbon source for certain basidiomycetes in poor natural soils. The contemporary decline in the number of basidiocarp initials to 0 to 36% in both fungi relative to the unplanted and aerated controls was caused by volatiles from rooted and unplanted soil and pointed thus to their ecological role as antibiotics, fumigants, toxins, and hormonal compounds. Aqueous extracts from root balls of wheat stimulated mycelial density and fruiting in A. macrocarpus contemporarily because of their contents in soil-derived macronutrients. They suppressed once more fruiting in the more sensitive Clitocybe sp. by active agents in the aqueous phase. Within plant rhizospheres, densities of Clitocybe sp. mycelia were stimulated in the presence of alfalfa, carrot, red clover, ryegrass, and spinach, whereas those of A. macrocarpus were halved by 7 of 10 plant species including alfalfa, red clover, ryegrass, and spinach. Mycelia of A. macrocarpus may thereby have

  20. Effects of transgenic Bt+CpTI cotton on the growth and reproduction of earthworm Eisenia foetida.

    Science.gov (United States)

    Liu, Biao; Cui, Jinjie; Meng, Jun; Hu, Wenjun; Luo, Junyu; Zheng, Yangping

    2009-01-01

    With the expansion of the planted area of transgenic Bt+CpTI cotton, the effects of this crop on non-target organisms in soil, including earthworms, are becoming the most important aspect of their ecological risk assessment. Laboratory toxicity studies were conducted to determine the effects of transgenic Bt+CpTI cotton leaves, containing high concentrations of the Bt toxin and cowpea trypsin inhibitor, on the earthworm Eisenia foetida. In comparison with the non-transgenic cotton line Zhong23, transgenic Bt+CpTI cotton Zhong41 had no significant acute toxicity on E. foetida. Moreover, the leaves of transgenic Bt+CpTI cotton were more suitable than the non-transgenic cotton Zhong23 for E. foetida growth and reproduction (time of reproduction, the number of cocoons and newly incubated offspring).

  1. Effects of chemical contaminants on growth, age-structure, and reproduction of Mytilus edulis complex from Puget sound, Washington.

    Science.gov (United States)

    Kagley, Anna N; Kardong, Kyle E; Snider, Robert G; Casillas, Edmundo

    2014-07-01

    Bivalves are used as sentinel species to detect chemical contaminants in the marine environment, but biological effects on indigenous populations that result from chemical exposure are largely unknown. We assessed age-weight, length-weight relationships, age structure, and reproductive status (i.e. fecundity, egg size) of the blue mussel Mytilus edulis complex from six sites in central Puget Sound, Washington, and one site in the relatively pristine area of northern Puget Sound. Results of this study suggest that mussels from urban areas of Puget Sound exhibit a lower growth rate, altered population age-structure, and potential reproductive impairment as a result of exposure to chemical contaminants. These findings support the use of mussels as sentinel species to assess the biological effects of contaminants on invertebrate populations.

  2. The role of insulin-like growth factor-1 (IGF-1) in growth and reproduction in female brown house snakes (Lamprophis fuliginosus).

    Science.gov (United States)

    Sparkman, A M; Byars, D; Ford, N B; Bronikowski, A M

    2010-09-15

    Insulin-like growth factor-1 (IGF-1) is a peptide hormone critically involved in the regulation of key life-history traits such as growth and reproduction. Its structure and function are well-characterized among diverse mammal, fish, and bird species; however, little is known regarding the activities of IGF-1 in non-avian reptiles, particularly snakes and lizards. Nevertheless, several unique characteristics of reptiles, such as high metabolic flexibility and remarkable diversity in life-history strategy, suggest that they are of great interest in the study of endocrinological mechanisms underlying the regulation and evolution of life-history traits. Here we test for a relationship between IGF-1 and individual feeding rate, growth rate and reproductive stage in lab-reared female offspring of wild-caught oviparous house snakes, Lamprophis fuliginosus. We confirm a positive correlation between IGF-1 and both feeding and growth rates in sexually immature snakes, similar to that reported in other taxa. We also show a family effect on IGF-1, suggesting that IGF-1 levels may be heritable in these snakes, and serve as an important target of selection to produce divergent life-history strategies. Furthermore, we provide evidence that suggests that IGF-1 may peak rapidly after first mating, and subsequently decline prior to egg-laying, a phenomenon not previously reported in other taxa. These findings suggest that further comparative study of IGF-1 in snakes may reveal both the extent to which IGF-1 function is conserved across major taxonomic groups, as well as novel and intriguing roles for IGF-1 in the regulation of reproductive activities. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  3. Modeling Math Growth Trajectory--An Application of Conventional Growth Curve Model and Growth Mixture Model to ECLS K-5 Data

    Science.gov (United States)

    Lu, Yi

    2016-01-01

    To model students' math growth trajectory, three conventional growth curve models and three growth mixture models are applied to the Early Childhood Longitudinal Study Kindergarten-Fifth grade (ECLS K-5) dataset in this study. The results of conventional growth curve model show gender differences on math IRT scores. When holding socio-economic…

  4. Nervous control of reproduction in Octopus vulgaris: a new model.

    Science.gov (United States)

    Di Cristo, Carlo

    2013-06-01

    The classic study of Wells and Wells on the control of reproduction in Octopus demonstrated that the activity of the subpedunculate lobe of the brain and environmental illumination both inhibit the release of an unknown gonadotropin from the optic gland. This inhibitory control may be exerted by the neuropeptide Phe-Met-Arg-Phe-NH₂ (FMRFamide). It was later demonstrated that the olfactory lobe is also likely to be involved in the control of optic gland activity. The presence of gonadotropin-releasing hormone in the olfactory lobe suggested that it might exert an excitatory action on optic gland activity. Other neuropeptides have now been localised in the olfactory lobe: neuropeptide Y, galanin, corticotropin-releasing factor, Ala-Pro-Gly-Trp-NH₂ (APGWamide), as well as steroidogenic enzymes and an oestrogen receptor orthologue. This supports the hypothesis that this lobe may also play a part in the control of reproduction in Octopus. The olfactory lobe receives distant chemical stimuli and also appears to be an integrative centre containing a variety of neuropeptides involved in controlling the onset of sexual maturation of Octopus, via the optic gland hormone. This review attempts to summarise current knowledge about the role of the olfactory lobe and optic gland in the control of sexual maturation in Octopus, in the light of new findings and in the context of molluscan comparative physiology.

  5. Influence of growth on reproductive traits and its effect on fertility and gene diversity in a clonal seed orchard of scots pine, Pinus Sylvestris L.

    Science.gov (United States)

    Dutkuner, I; Bilir, N; Ulusan, D

    2008-05-01

    This study was carried out in a clonal seed orchard of scots pine (Pinus sylvestris L.), to determine the difference and interaction for reproductive and growth characters among clones and its impact on fertility variation and gene diversity Numbers of female and male strobili, and height and diameter at breast height were studied on six grafts chosen randomly in each of the 27 clones for the purpose. One-way analysis of variance revealed large differences in both reproductive and growth characters among clones. The differences were higher in growth characters than in reproductive traits. There was significant phenotypic correlation among growth and reproductive characters. So, growth characters had a greater effect on male and female fertility Estimates of total fertility variation (Sibling coefficient = 1.012), status number (26.8) and relative gene diversity (0.981) were computed. Fertility variation among clones was low, which caused a high relative population size (99% of census number). The positive phenotypic correlation between growth and reproductive characters showed that enhanced growth rate could be effective in improving fertility and gene diversity of seed orchard crop. The results of the study have implications in breeding and selection of plus tree and populations, establishment and thinning of seed orchards of the species.

  6. Effect of seed morph and light level on growth and reproduction of the amphicarpic plant Amphicarpaea edgeworthii (Fabaceae)

    Science.gov (United States)

    Zhang, Keliang; Baskin, Jerry M.; Baskin, Carol C.; Yang, Xuejun; Huang, Zhenying

    2017-01-01

    Amphicarpic plants produce aerial and subterranean fruits on an individual plant, and these heteromorphic diaspores give rise to plants that differ in growth and ecology. Amphicarpaea edgeworthii is a summer annual amphicarpic species that grows over a range of light levels. We aimed to compare the response to shading intensity of plants of A. edgeworthii grown throughout their life cycle from aerial seeds (ASP) and from subterranean seeds (SSP). We hypothesized that vegetative and reproductive growth of plants from ASP and SSP respond differently to light. Plants were grown from ASP and SSP under 0, 46, 71 and 90% shading intensities. With plant height as a covariate, vegetative biomass of ASP and SSP did not differ. Leaf area and seed production of SSP were greater and internode length less than they were for ASP in all shading intensities. Aerial and subterranean seed yield, seed mass and number for both ASP and SSP were highest in full light. Aerial seed yield was affected more than subterranean seed yield by shading intensity. The growth and reproductive responses of ASP and SSP of A. edgeworthii may be adaptive to the range of low to high light environments in which this species grows. PMID:28071671

  7. Associated fauna and effects of epibiotic barnacles on the relative growth and reproductive indices of Stramonita haemastoma (Gastropoda: Muricidae

    Directory of Open Access Journals (Sweden)

    Tahani El Ayari

    2015-06-01

    Full Text Available To better understand the impacts of biofouling on the biological processes of the basibiont, the effects of epibiotic barnacles on the relative growth and reproductive indices of Stramonita haemastoma (Linnaeus, 1767 were assessed. A total of 1035 specimens were collected monthly for one year from Bizerta Channel (northern Tunisia. Endobiotic species comprised the lithophagous bivalves Lithophaga aristata and Rocellaria dubia of different sizes, communicating with the outside through tiny perforations. Intra-shell tunnels and galleries also sheltered annelids and sipunculids. Epibiotic species comprised algae and highly diversified invertebrates represented by crustaceans, polychaetes, molluscs, echinoderms, ascidians, sponges, bryozoans and sipunculids, with barnacles being the most common group. Comparison of growth features between non-fouled and fouled S. haemastoma revealed higher growth in non-fouled specimens. Differences in reproductive condition indices were detected in few months, being mostly higher in non-fouled snails, but showed no asynchrony in the spawning period for either fouled or non-fouled gastropods hosts.

  8. Fishery status, growth, reproduction biology and feeding habit of two scombrid fish from the Gulf of Aqaba, Red Sea

    International Nuclear Information System (INIS)

    Al-Zibdah, M.; Odat, N.

    2007-01-01

    The fishery and some biological aspects of two Scombrid fish species, Katsuwonus pelamis and Euthynnus affinis from the Gulf of Aqaba were studied during one year period (1999-2000). Monthly samples of the two species were collected to investigate growth, reproduction and feeding habit. Results showed that the Scombridae family form more than 60% of the total catch of Jordanian fishery. The length-weight relationships (LWr) in the two fish species demonstrated thatthe growth is of an allometric type (around 3). The condition factor (k) showed relatively consistent values in both species but revealed slight variability in growth periods. This could be attributed to the limited food availability in fish natural habitat. Different age classes were observed in the catch of the two species irrespective of season. The mean GSI exhibited similar change pattern with season in both sexes of the two fish. Spawning behavior and planktonic larvae of both fish were not observed in the field. This could be inferred that these fish are not migrating to the region for reproduction. The food composition of K. pelamis and E. affinis suggests that the fish compete for the same food items. These are the fish At herinomorous lacunosus, crustacean and molluscans. Prey occurrence in fish stomachs is attributed mainly to the seasonal availability of food in the Gulf of Aqaba. High abundance of food items in winter may indicate that the two species migrate at the climax of primary productivity in the Gulf. (author)

  9. Nonlinear Growth Models as Measurement Models: A Second-Order Growth Curve Model for Measuring Potential.

    Science.gov (United States)

    McNeish, Daniel; Dumas, Denis

    2017-01-01

    Recent methodological work has highlighted the promise of nonlinear growth models for addressing substantive questions in the behavioral sciences. In this article, we outline a second-order nonlinear growth model in order to measure a critical notion in development and education: potential. Here, potential is conceptualized as having three components-ability, capacity, and availability-where ability is the amount of skill a student is estimated to have at a given timepoint, capacity is the maximum amount of ability a student is predicted to be able to develop asymptotically, and availability is the difference between capacity and ability at any particular timepoint. We argue that single timepoint measures are typically insufficient for discerning information about potential, and we therefore describe a general framework that incorporates a growth model into the measurement model to capture these three components. Then, we provide an illustrative example using the public-use Early Childhood Longitudinal Study-Kindergarten data set using a Michaelis-Menten growth function (reparameterized from its common application in biochemistry) to demonstrate our proposed model as applied to measuring potential within an educational context. The advantage of this approach compared to currently utilized methods is discussed as are future directions and limitations.

  10. Asymmetric changes of growth and reproductive investment herald altitudinal and latitudinal range shifts of two woody species.

    Science.gov (United States)

    Matías, Luis; Jump, Alistair S

    2015-02-01

    Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of the geographical distribution of a species, where range expansions or contractions may occur. Current demographical status at geographical range limits can help us to predict population trends and their implications for the future distribution of the species. Thus, understanding the comparability of demographical patterns occurring along both altitudinal and latitudinal gradients would be highly informative. In this study, we analyse the differences in the demography of two woody species through altitudinal gradients at their southernmost distribution limit and the consistency of demographical patterns at the treeline across a latitudinal gradient covering the complete distribution range. We focus on Pinus sylvestris and Juniperus communis, assessing their demographical structure (density, age and mortality rate), growth, reproduction investment and damage from herbivory on 53 populations covering the upper, central and lower altitudes as well as the treeline at central latitude and northernmost and southernmost latitudinal distribution limits. For both species, populations at the lowermost altitude presented older age structure, higher mortality, decreased growth and lower reproduction when compared to the upper limit, indicating higher fitness at the treeline. This trend at the treeline was generally maintained through the latitudinal gradient, but with a decreased growth at the northern edge for both species and lower reproduction for P. sylvestris. However, altitudinal and latitudinal transects are not directly comparable as factors other than climate, including herbivore pressure or human management, must be taken into account if we are to understand how to infer latitudinal processes from altitudinal data. © 2014 John Wiley & Sons Ltd.

  11. Pore-Scale Model for Microbial Growth

    Science.gov (United States)

    Tartakovsky, G.; Tartakovsky, A. M.; Scheibe, T. D.

    2011-12-01

    A lagrangian particle model based on smoothed particle hydrodynamics (SPH) is used to simulate pore-scale flow, reactive transport and biomass growth which is controlled by the mixing of an electron donor and acceptor, in a microfluidic porous cell. The experimental results described in Ch. Zhang et al "Effects of pore-scale heterogeneity and transverse mixing on bacterial growth in porous media" were used for this study. The model represents the homogeneous pore structure of a uniform array of cylindrical posts with microbes uniformly distributed on the grain surfaces. Each one of the two solutes (electron donor and electron acceptor) enters the domain unmixed through separate inlets. In the model, pair-wise particle-particle interactions are used to simulate interactions within the biomass, and both biomass-fluid and biomass-soil grain interactions. The biomass growth rate is described by double Monod kinetics. For the set of parameters used in the simulations the model predicts that: 1) biomass grows in the shape of bridges connecting soil grains and oriented in the direction of flow so as to minimize resistance to the fluid flow; and 2) the biomass growth occurs only in the mixing zone. Using parameters available in the literature, the biomass growth model agrees qualitatively with the experimental results. In order to achieve quantitative agreement, model calibration is required.

  12. Variability in age and size at maturation, reproductive longevity, and long-term growth dynamics for Kemp's ridley sea turtles in the Gulf of Mexico.

    Directory of Open Access Journals (Sweden)

    Larisa Avens

    Full Text Available Effective management of protected sea turtle populations requires knowledge not only of mean values for demographic and life-history parameters, but also temporal and spatial trends, variability, and underlying causes. For endangered Kemp's ridley sea turtles (Lepidochelys kempii, the need for baseline information of this type has been emphasized during attempts to understand causes underlying the recent truncation in the recovery trajectory for nesting females. To provide insight into variability in age and size at sexual maturation (ASM and SSM and long-term growth patterns likely to influence population trends, we conducted skeletochronological analysis of humerus bones from 333 Kemp's ridleys stranded throughout the Gulf of Mexico (GOM from 1993 to 2010. Ranges of possible ASMs (6.8 to 21.8 yr and SSMs (53.3 to 68.3 cm straightline carapace length (SCL estimated using the "rapprochement" skeletal growth mark associated with maturation were broad, supporting incorporation of a maturation schedule in Kemp's ridley population models. Mean ASMs estimated from rapprochement and by fitting logistic, generalized additive mixed, and von Bertalanffy growth models to age and growth data ranged from 11 to 13 yr; confidence intervals for the logistic model predicted maturation of 95% of the population between 11.9 and 14.8 yr. Early juvenile somatic growth rates in the GOM were greater than those previously reported for the Atlantic, indicating potential for differences in maturation trajectories between regions. Finally, long-term, significant decreases in somatic growth response were found for both juveniles and adults, which could influence recruitment to the reproductive population and observed nesting population trends.

  13. Using time-dependent models to investigate body condition and growth rate of the giant gartersnake

    Science.gov (United States)

    Coates, P.S.; Wylie, G.D.; Halstead, B.J.; Casazza, Michael L.

    2009-01-01

    Identifying links between phenotypic attributes and fitness is a primary goal of reproductive ecology. Differences in within-year patterns of body condition between sexes of gartersnakes in relation to reproduction and growth are not fully understood. We conducted an 11-year field study of body condition and growth rate of the giant gartersnake Thamnophis gigas across 13 study areas in the Central Valley of California, USA. We developed a priori mixed effects models of body condition index (BCI), which included covariates of time, sex and snout-vent length and reported the best-approximating models using an information theoretic approach. Also, we developed models of growth rate index (GRI) using covariates of sex and periods based on reproductive behavior. The largest difference in BCI between sexes, as predicted by a non-linear (cubic) time model, occurred during the mating period when female body condition (0.014??0.001 se) was substantially greater than males (-0.027??0.002 se). Males likely allocated energy to search for mates, while females likely stored energy for embryonic development. We also provided evidence that males use more body energy reserves than females during hibernation, perhaps because of different body temperatures between sexes. We found GRI of male snakes was substantially lower during the mating period than during a non-mating period, which indicated that a trade-off existed between searching for mates and growth. These findings contribute to our understanding of snake ecology in a Mediterranean climate. ?? 2009 The Zoological Society of London.

  14. Effects of a Glucocorticoid Receptor Agonist, Dexamethasone, on Fathead Minnow Reproduction, Growth, and Development.

    Science.gov (United States)

    Few studies have examined the effects of synthetic glucocorticoids on the reproductive axis of fish, despite the fact that these chemicals are therapeutically prescribed anti-inflammatory agents that are abundantly produced and consumed. To generate data to assess potential risk ...

  15. Crop growth model WOFOST applied to potatoes

    NARCIS (Netherlands)

    Koning, de G.H.J.; Diepen, van C.A.; Reinds, G.J.

    1995-01-01

    The WOFOST model was calibrated with an experiment on yield effects of drought in potatoes, using data on weather, soil moisture and crop calendar. Then, crop growth and development were predicted for the next year, using planting date and weather data. The model is described. The adjustments in the

  16. Modelling the growth of a methanotrophic biofilm

    DEFF Research Database (Denmark)

    Arcangeli, J.-P.; Arvin, E.

    1999-01-01

    This article discusses the growth of methanotrophic biofilms. Several independent biofilm growths scenarios involving different inocula were examined. Biofilm growth, substrate removal and product formation were monitored throughout the experiments. Based on the oxygen consumption it was concluded...... that heterotrophs and nitrifiers co-existed with methanotrophs in the biofilm. Heterotrophic biomass grew on soluble polymers formed by the hydrolysis of dead biomass entrapped in the biofilm. Nitrifier populations developed because of the presence of ammonia in the mineral medium. Based on these experimental...... results, the computer program AQUASIM was used to develop a biological model involving methanotrophs, heterotrophs and nitrifiers. The modelling of six independent growth experiments showed that stoichiometric and kinetic parameters were within the same order of magnitude. Parameter estimation yielded...

  17. Structural modelling of economic growth: Technological changes

    Directory of Open Access Journals (Sweden)

    Sukharev Oleg

    2016-01-01

    Full Text Available Neoclassical and Keynesian theories of economic growth assume the use of Cobb-Douglas modified functions and other aggregate econometric approaches to growth dynamics modelling. In that case explanations of economic growth are based on the logic of the used mathematical ratios often including the ideas about aggregated values change and factors change a priori. The idea of assessment of factor productivity is the fundamental one among modern theories of economic growth. Nevertheless, structural parameters of economic system, institutions and technological changes are practically not considered within known approaches, though the latter is reflected in the changing parameters of production function. At the same time, on the one hand, the ratio of structural elements determines the future value of the total productivity of the factors and, on the other hand, strongly influences the rate of economic growth and its mode of innovative dynamics. To put structural parameters of economic system into growth models with the possibility of assessment of such modes under conditions of interaction of new and old combinations is an essential step in the development of the theory of economic growth/development. It allows forming stimulation policy of economic growth proceeding from the structural ratios and relations recognized for this economic system. It is most convenient in such models to use logistic functions demonstrating the resource change for old and new combination within the economic system. The result of economy development depends on starting conditions, and on institutional parameters of velocity change of resource borrowing in favour of a new combination and creation of its own resource. Model registration of the resource is carried out through the idea of investments into new and old combinations.

  18. In silico modeling for tumor growth visualization.

    Science.gov (United States)

    Jeanquartier, Fleur; Jean-Quartier, Claire; Cemernek, David; Holzinger, Andreas

    2016-08-08

    Cancer is a complex disease. Fundamental cellular based studies as well as modeling provides insight into cancer biology and strategies to treatment of the disease. In silico models complement in vivo models. Research on tumor growth involves a plethora of models each emphasizing isolated aspects of benign and malignant neoplasms. Biologists and clinical scientists are often overwhelmed by the mathematical background knowledge necessary to grasp and to apply a model to their own research. We aim to provide a comprehensive and expandable simulation tool to visualizing tumor growth. This novel Web-based application offers the advantage of a user-friendly graphical interface with several manipulable input variables to correlate different aspects of tumor growth. By refining model parameters we highlight the significance of heterogeneous intercellular interactions on tumor progression. Within this paper we present the implementation of the Cellular Potts Model graphically presented through Cytoscape.js within a Web application. The tool is available under the MIT license at https://github.com/davcem/cpm-cytoscape and http://styx.cgv.tugraz.at:8080/cpm-cytoscape/ . In-silico methods overcome the lack of wet experimental possibilities and as dry method succeed in terms of reduction, refinement and replacement of animal experimentation, also known as the 3R principles. Our visualization approach to simulation allows for more flexible usage and easy extension to facilitate understanding and gain novel insight. We believe that biomedical research in general and research on tumor growth in particular will benefit from the systems biology perspective.

  19. Peer group as a model for the development learning reproductive health in the traditional boarding school

    Directory of Open Access Journals (Sweden)

    awatiful azza

    2016-04-01

    Full Text Available Introduction: Teen problems are conditions that need to be considered in national development in Indonesia. Teenagers problems occur, because they are not prepared regarding knowledge of aspects related to the problem of transition from childhood to adulthood. One of the problems faced by teenagers today is about the health of adolescents, especially related to reproductive health. Methods: This study uses a quantitative approach pre experiment with pre - post test design, the purpose of research, construction of models of healthy reproductive learning through peer groups in traditional schools and analyze the application of learning through peer group against knowledge female students  about reproductive health. The sample was female students in Boarding school Miftahul Hasan Gunung Sepikul amounted to 50 female students, with purposive sampling technique. Results of analysis using Spearman's rho test ,P value of 0.00 obtained value where the value is < less than 0.05 so it can be concluded that there is a learning effect of reproductive health through peer groups for knowledge  female students . Discuss: Boarding schools need to provide curriculum on reproductive health in order to improve the understanding of female students in healthy living behavior associated with reproductive organs.

  20. Beyond R 0: Demographic Models for Variability of Lifetime Reproductive Output

    Science.gov (United States)

    Caswell, Hal

    2011-01-01

    The net reproductive rate measures the expected lifetime reproductive output of an individual, and plays an important role in demography, ecology, evolution, and epidemiology. Well-established methods exist to calculate it from age- or stage-classified demographic data. As an expectation, provides no information on variability; empirical measurements of lifetime reproduction universally show high levels of variability, and often positive skewness among individuals. This is often interpreted as evidence of heterogeneity, and thus of an opportunity for natural selection. However, variability provides evidence of heterogeneity only if it exceeds the level of variability to be expected in a cohort of identical individuals all experiencing the same vital rates. Such comparisons require a way to calculate the statistics of lifetime reproduction from demographic data. Here, a new approach is presented, using the theory of Markov chains with rewards, obtaining all the moments of the distribution of lifetime reproduction. The approach applies to age- or stage-classified models, to constant, periodic, or stochastic environments, and to any kind of reproductive schedule. As examples, I analyze data from six empirical studies, of a variety of animal and plant taxa (nematodes, polychaetes, humans, and several species of perennial plants). PMID:21738586

  1. Plastic growth of the herbivorous reef fish Sparisoma viride: field evidence for a trade-off between growth and reproduction

    NARCIS (Netherlands)

    van Rooij, J.M.; Bruggemann, J.H.; Videler, J.J.; Breeman, A.M.

    The growth of different Life phases and social categories of the protogynous parrotfish Sparisoma viride was studied on a fringing reef on Bonaire (Netherlands Antilles) using mark-recapture procedures and by taking repeated stereographic measurements of free-swimming fish. Weight-growth was best

  2. Pros and cons of estimating the reproduction number from early epidemic growth rate of influenza A (H1N1 2009

    Directory of Open Access Journals (Sweden)

    Chowell Gerardo

    2010-01-01

    Full Text Available Abstract Background In many parts of the world, the exponential growth rate of infections during the initial epidemic phase has been used to make statistical inferences on the reproduction number, R, a summary measure of the transmission potential for the novel influenza A (H1N1 2009. The growth rate at the initial stage of the epidemic in Japan led to estimates for R in the range 2.0 to 2.6, capturing the intensity of the initial outbreak among school-age children in May 2009. Methods An updated estimate of R that takes into account the epidemic data from 29 May to 14 July is provided. An age-structured renewal process is employed to capture the age-dependent transmission dynamics, jointly estimating the reproduction number, the age-dependent susceptibility and the relative contribution of imported cases to secondary transmission. Pitfalls in estimating epidemic growth rates are identified and used for scrutinizing and re-assessing the results of our earlier estimate of R. Results Maximum likelihood estimates of R using the data from 29 May to 14 July ranged from 1.21 to 1.35. The next-generation matrix, based on our age-structured model, predicts that only 17.5% of the population will experience infection by the end of the first pandemic wave. Our earlier estimate of R did not fully capture the population-wide epidemic in quantifying the next-generation matrix from the estimated growth rate during the initial stage of the pandemic in Japan. Conclusions In order to quantify R from the growth rate of cases, it is essential that the selected model captures the underlying transmission dynamics embedded in the data. Exploring additional epidemiological information will be useful for assessing the temporal dynamics. Although the simple concept of R is more easily grasped by the general public than that of the next-generation matrix, the matrix incorporating detailed information (e.g., age-specificity is essential for reducing the levels of

  3. Cost of reproduction in the Queensland fruit fly: Y-model versus lethal protein hypothesis.

    Science.gov (United States)

    Fanson, Benjamin G; Fanson, Kerry V; Taylor, Phillip W

    2012-12-22

    The trade-off between lifespan and reproduction is commonly explained by differential allocation of limited resources. Recent research has shown that the ratio of protein to carbohydrate (P : C) of a fly's diet mediates the lifespan-reproduction trade-off, with higher P : C diets increasing egg production but decreasing lifespan. To test whether this P : C effect is because of changing allocation strategies (Y-model hypothesis) or detrimental effects of protein ingestion on lifespan (lethal protein hypothesis), we measured lifespan and egg production in Queensland fruit flies varying in reproductive status (mated, virgin and sterilized females, virgin males) that were fed one of 18 diets varying in protein and carbohydrate amounts. The Y-model predicts that for sterilized females and for males, which require little protein for reproduction, there will be no effect of P : C ratio on lifespan; the lethal protein hypothesis predicts that the effect of P : C ratio should be similar in all groups. In support of the lethal protein hypothesis, and counter to the Y-model, the P : C ratio of the ingested diets had similar effects for all groups. We conclude that the trade-off between lifespan and reproduction is mediated by the detrimental side-effects of protein ingestion on lifespan.

  4. Assessment of MARMOT Grain Growth Model

    Energy Technology Data Exchange (ETDEWEB)

    Fromm, B. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Zhang, Y. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Schwen, D. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Fuel Modeling and Simulation Dept.; Brown, D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pokharel, R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-01

    This report assesses the MARMOT grain growth model by comparing modeling predictions with experimental results from thermal annealing. The purpose here is threefold: (1) to demonstrate the validation approach of using thermal annealing experiments with non-destructive characterization, (2) to test the reconstruction capability and computation efficiency in MOOSE, and (3) to validate the grain growth model and the associated parameters that are implemented in MARMOT for UO2. To assure a rigorous comparison, the 2D and 3D initial experimental microstructures of UO2 samples were characterized using non-destructive Synchrotron x-ray. The same samples were then annealed at 2273K for grain growth, and their initial microstructures were used as initial conditions for simulated annealing at the same temperature using MARMOT. After annealing, the final experimental microstructures were characterized again to compare with the results from simulations. So far, comparison between modeling and experiments has been done for 2D microstructures, and 3D comparison is underway. The preliminary results demonstrated the usefulness of the non-destructive characterization method for MARMOT grain growth model validation. A detailed analysis of the 3D microstructures is in progress to fully validate the current model in MARMOT.

  5. Effect of Temperature on Biochemical Composition, Growth and Reproduction of the Ornamental Red Cherry Shrimp Neocaridina heteropoda heteropoda (Decapoda, Caridea)

    Science.gov (United States)

    Tropea, Carolina; Stumpf, Liane; López Greco, Laura Susana

    2015-01-01

    The effect of water temperature on biochemical composition, growth and reproduction of the ornamental shrimp, Neocaridina heteropoda heteropoda, was investigated to determine the optimum temperature for its culture. The effect of embryo incubation temperature on the subsequent performance of juveniles was also evaluated. Ovigerous females and recently hatched juveniles (JI) were maintained during egg incubation and for a 90-day period, respectively, at three temperatures (24, 28 and 32°C). Incubation period increased with decreasing water temperature, but the number and size of JI were similar among treatments. At day 30 of the 90-day period, body weight and growth increment (GI) at 24°C were lower than those at 28 and 32°C. On subsequent days, GI at 24°C exceeded that at 28 and 32°C, leading to a similar body weight among treatments. These results suggest growth was delayed at 24°C, but only for 30 days after hatching. The lipid concentration tended to be lowest, intermediate and highest at 28, 32 and 24°C, respectively, possibly as a consequence of the metabolic processes involved in growth and ovarian maturation. Protein and glycogen concentrations were similar among treatments. Both the growth trajectory and biochemical composition of shrimps were affected by the temperature experienced during the 90-day growth period independently of the embryo incubation temperature. During the growth period, shrimps reached sexual maturity and mated, with the highest proportion of ovigerous females occurring at 28°C. All the females that matured and mated at 32°C lost their eggs, indicating a potentially stressful effect of high temperature on ovarian maturation. Based on high survival and good growth performance of shrimps at the three temperatures tested over the 90-day period it is concluded that N. heteropoda heteropoda is tolerant to a wide range of water temperatures, with 28°C being the optimum temperature for its culture. PMID:25768918

  6. Growth, reproduction and possible recruitment variability in the abyssal brittle star Ophiocten hastatum (Ophiuroidea: Echinodermata) in the NE Atlantic

    Science.gov (United States)

    Gage, John D.; Anderson, Roslyn M.; Tyler, Paul A.; Chapman, Rachel; Dolan, Emily

    2004-06-01

    Growth was studied from skeletal growth markers in the cosmopolitan abyssal brittle star Ophiocten hastatm. Samples for analysis were taken at five sites located in the southern (2900 m) and central (2000 m) Rockall Trough, at ca. 3000 and 4000 m in the Porcupine Seabight, and at 4850 m on the Porcupine Abyssal Plain. Growth bands were assumed to reflect an annual cycle in skeletal growth. Band measurements on arm vertebrae, standardised to disc diameter, were used to provide size-at-age data and size-increment data that took into account overgrowth of early bands in older individuals. The Richards growth function marginally provides best fit to pooled size-at-age data, although the asymptote-less Tanaka function and the Gompertz growth function also provided good fit to size-at-age data which showed a rather linear growth pattern with little indication of a growth asymptote. Log e transformed size-increment data were linearised by applying the Ford-Walford method to approximate Gompertz growth so that growth could be compared at the five sites. Grouped linear regression and analysis of covariance showed no significant differences between growth at the sites and a common fitted regression. However, pairwise comparisons suggest growth differences with increasing bathymetric separation. Oocyte size frequencies measured from histological preparations of the gonad of specimens from the Porcupine Abyssal Plain indicate marked reproductive periodicity, with spawn-out in late winter that is likely followed by planktotrophic early development in spring with benthic settlement in summer. Although usually rare in the trawl and epibenthic sled samples, several years of successful recruitment followed by a period when recruitment was low or absent might explain size structure observed in a single unusually large sample from the Rockall Trough. This is consistent with previous observations during the late 1990s of a large population increase on the Porcupine Abyssal Plain

  7. Divergence for residual feed intake of Holstein-Friesian cattle during growth did not affect production and reproduction during lactation.

    Science.gov (United States)

    Macdonald, K A; Thomson, B P; Waghorn, G C

    2016-11-01

    Residual feed intake (RFI) is the difference between actual and predicted dry matter intake (DMI) of individual animals. Recent studies with Holstein-Friesian calves have identified an ~20% difference in RFI during growth (calf RFI) and these groups remained divergent in RFI during lactation. The objective of the experiment described here was to determine if cows selected for divergent RFI as calves differed in milk production, reproduction or in the profiles of BW and body condition score (BCS) change during lactation, when grazing pasture. The cows used in the experiment (n=126) had an RFI of -0.88 and +0.75 kg DM intake/day for growth as calves (efficient and inefficient calf RFI groups, respectively) and were intensively grazed at four stocking rates (SR) of 2.2, 2.6, 3.1 and 3.6 cows/ha on self-contained farmlets, over 3 years. Each SR treatment had equal number of cows identified as low and high calf RFI, with 24, 28, 34 and 40/11 ha farmlet. The cows divergent for calf RFI were randomly allocated to each SR. Although SR affected production, calf RFI group (low or high) did not affect milk production, reproduction, BW, BCS or changes in these parameters throughout lactation. The most efficient animals (low calf RFI) lost similar BW and BCS as the least efficient (high calf RFI) immediately post-calving, and regained similar BW and BCS before their next calving. These results indicate that selection for RFI as calves to increase efficiency of feed utilisation did not negatively affect farm productivity variables (milk production, BCS, BW and reproduction) as adults when managed under an intensive pastoral grazing system.

  8. Ewe lambs with higher breeding values for growth achieve higher reproductive performance when mated at age 8 months.

    Science.gov (United States)

    Nieto, C A Rosales; Ferguson, M B; Macleay, C A; Briegel, J R; Wood, D A; Martin, G B; Thompson, A N

    2013-09-15

    We studied the relationships among growth, body composition and reproductive performance in ewe lambs with known phenotypic values for depth of eye muscle (EMD) and fat (FAT) and Australian Sheep Breeding Values for post-weaning live weight (PWT) and depth of eye muscle (PEMD) and fat (PFAT). To detect estrus, vasectomized rams were placed with 190 Merino ewe lambs when on average they were 157 days old. The vasectomized rams were replaced with entire rams when the ewe lambs were, on average, 226 days old. Lambs were weighed every week and blood was sampled on four occasions for assay of ghrelin, leptin and ß-hydroxybutyrate. Almost 90% of the lambs attained puberty during the experiment, at an average live weight of 41.4 kg and average age of 197 days. Ewe lambs with higher values for EMD (P ewe lambs attained puberty, as detected by vasectomized rams, but then failed to become pregnant after mating with entire rams. Nevertheless, we can conclude that in ewe lambs mated at 8 months of age, higher breeding values for growth, muscle and fat are positively correlated with reproductive performance, although the effects of breeding values and responses to live weight are highly variable. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Effects of active immunization against growth-hormone releasing factor on puberty and reproductive development in gilts.

    Science.gov (United States)

    Swanchara, K W; Armstrong, J D; Britt, J H

    1999-07-01

    Hormones within the somatotropin cascade influence several physiological traits, including growth and reproduction. Active immunization against growth hormone-releasing factor (GRFi) initiated at 3 or 6 mo of age decreased weight gain, increased deposition of fat, and delayed puberty in heifers. Two experiments were conducted to investigate the effects of GRFi on puberty and subsequent ovulation rate in gilts. Crossbred gilts were actively immunized against GRF-(1-29)-(Gly)2-Cys-NH2 conjugated to human serum albumin (GRFi) or against human serum albumin alone (HSAi). In Exp. 1, gilts were immunized against GRF (n = 12) or HSA (n = 12) at 92 +/- 1 d of age. At 191 d of age, antibody titers against GRF were greater (P gilts. The GRFi decreased (P gilts were immunized against GRF (n = 35) or HSA (n = 35) at 35 +/- 1 d of age. The GRFi at 35 d of age did not alter the number of surface follicles or uterine weight between 93 and 102 d of age, but GRFi decreased (P Immunization against GRF reduced (P gilts, but ovulation rate was lower (P gilts. Thus, GRFi at 92 or 35 d of age decreased serum ST, IGF-I, and BW in prepubertal gilts without altering age of puberty. However, GRFi at 35 d of age, but not 92 d of age, decreased ovulation rate. These results indicate that alterations in the somatotropic axis at 1 mo of age can influence reproductive development in pubertal gilts.

  10. Effects of decabromodiphenyl ether (BDE-209) on the avoidance response, survival, growth and reproduction of earthworms (Eisenia fetida).

    Science.gov (United States)

    Xie, Xianchuan; Qian, Yan; Wu, Yingxin; Yin, Jun; Zhai, Jianping

    2013-04-01

    The effects of decabromodiphenyl ether (BDE-209) on avoidance response, survival, growth, and reproduction of earthworms (Eisenia fetida) were investigated under laboratory conditions using natural and artificial soils as substrate. Results showed that no significant avoidance response was observed when earthworms were exposed to 0.1-1000 mg/kg of BDE-209 for 48 h. After 28-days exposure, no significant effects on survival and growth of adult earthworms was induced by 0.1-1000 mg/kg of BDE-209 indicating the Lowest Observed Effect Level (LOEL) of BDE-209 on their survival and body weight was more than 1000 mg/kg. Except for a significant decrease in the number of juveniles per hatched cocoon in artificial soils at 1000 mg/kg of BDE-209, no significant effects on reproductive parameters (e.g. cocoon production per earthworms, weight per cocoon and cocoon hatchability) were observed. These results suggest that adult earthworms have a strong tolerance for BDE-209 exposure in soils, but a potential toxicity does exist for earthworm embryos or juveniles. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Effects of fluoride on screech owl reproduction: Teratological evaluation, growth, and blood chemistry in hatchlings

    Science.gov (United States)

    Hoffman, D.J.; Pattee, O.H.; Wiemeyer, Stanley N.

    1985-01-01

    The effects on reproduction in screech owls (Otus asio) of chronic dietary sodium fluoride administration at 0, 40, and 200 ppm were examined. Fluoride at 40 ppm resulted in a significantly smaller egg volume, while 200 ppm also resulted in lower egg weights and lengths. Day-one hatchlings in the 200 ppm group weighed almost 10% less than controls and had shorter crown-rump lengths. No gross abnormalities were apparent. Skeletal clearing and staining revealed significantly shorter tibiotarsus lengths in the 40 ppm and 200 ppm groups and a shorter radius-ulna length in the 200 ppm group. By 7 days of age, body weights and lengths did not differ from controls, but the tibiotarsus in the 200 ppm group remained shorter. No significant differences were detected in hematocrit, hemoglobin, plasma calcium or alkaline phosphatase. Plasma phosphorus levels were higher in the 40 ppm group than in controls. These results, in combination with the findings of Pattee et al. [25], revealed significant impairment of overall reproduction, suggesting that sodium fluoride could cause slight to moderate reproduction disorders in owls in fluoride-polluted areas.

  12. Sea urchin (Paracentrotus lividus) cryopreserved embryos survival and growth: effects of cryopreservation parameters and reproductive seasonality.

    Science.gov (United States)

    Paredes, P; Bellas, J

    2014-01-01

    The cryopreservation of embryos can be a powerful biotechnological tool to supply all year-round biological material for sea urchin aquaculture production. This study investigates different methodological and biological factors that may affect the result of the cryopreservation process of sea urchin (Paracentrotus lividus) embryos. Our data indicate that neither embryo density nor the use of different cryopreservation containers presented effect on the cryopreservation outcome. Contrary to other marine invertebrates, for sea urchin embryo cryopreservation ultrapure water cannot be used as CPA solvent, yielding zero survival. After studying the reproductive parameters along the reproductive season, we found a positive correlation between both male and female Condition Index (C.I.), and between the oocyte weight and C.I. Both the histology study of female gonads and the C.I. variation, suggest that the sea urchin natural spawning period in the Ría de Vigo occurs between June and July. We found no correlation between any of the reproductive parameters monitored and the cryopreservation outcome.

  13. Factors contributing to the accumulation of reproductive isolation: A mixed model approach.

    Science.gov (United States)

    Castillo, Dean M

    2017-08-01

    The analysis of large datasets describing reproductive isolation between species has been extremely influential in the study of speciation. However, the statistical methods currently used for these data limit the ability to make direct inferences about the factors predicting the evolution of reproductive isolation. As a result, our understanding of iconic patterns and rules of speciation rely on indirect analyses that have clear statistical limitations. Phylogenetic mixed models are commonly used in ecology and evolution, but have not been applied to studies of reproductive isolation. Here I describe a flexible framework using phylogenetic mixed models to analyze data collected at different evolutionary scales, to test both categorical and continuous predictor variables, and to test the effect of multiple predictors on rates and patterns of reproductive isolation simultaneously. I demonstrate the utility of this framework by re-analyzing four classic datasets, from both animals and plants, and evaluating several hypotheses that could not be tested in the original studies: In the Drosophila and Bufonidae datasets, I found support for more rapid accumulation of reproductive isolation in sympatric species pairs compared to allopatric species pairs. Using Silene and Nolana , I found no evidence supporting the hypothesis that floral differentiation elevates postzygotic reproductive isolation. The faster accumulation of postzygotic isolation in sympatry is likely the result of species coexistence determined by the level of postzygotic isolation between species. In addition, floral trait divergence does not appear to translate into pleiotropic effects on postzygotic reproductive isolation. Overall, these methods can allow researchers to test new hypotheses using a single statistical method, while remedying the statistical limitations of several previous methods.

  14. Stochastic Growth Models with No Discounting

    Czech Academy of Sciences Publication Activity Database

    Sladký, Karel

    2007-01-01

    Roč. 15, č. 4 (2007), s. 88-98 ISSN 0572-3043 R&D Projects: GA ČR(CZ) GA402/06/0990; GA ČR GA402/05/0115 Institutional research plan: CEZ:AV0Z10750506 Keywords : economic dynamics * stochastic version of the Ramsey growth model * Markov decision processes Subject RIV: AH - Economics

  15. Modelling oxide formation and growth on platinum

    Science.gov (United States)

    Baroody, Heather A.; Jerkiewicz, Gregory; Eikerling, Michael H.

    2017-04-01

    We present a mathematical model of oxide formation and growth on platinum. The motivation stems from the necessity to understand platinum dissolution in the cathode catalyst layer of polymer electrolyte fuel cells. As is known, platinum oxide formation and reduction are strongly linked to platinum dissolution processes. However, a consistent model of the oxidation processes on platinum does not exist. Our oxide growth model links interfacial exchange processes between platinum and oxygen ions with the transport of oxygen ion vacancies via diffusion and migration. A parametric analysis is performed to rationalize vital trends in oxide growth kinetics. The rate determining step of oxide formation and growth is identified as the extraction of platinum atoms at the metal-oxide interface. A kinetic effect is observed while adjusting the potential when growing the oxide layer, and the solution indicates that a structural change occurs at high potentials, around 1.5 VRHE. The model compares well to experimental data for various materials from various sources.

  16. Modeling Fish Growth in Low Dissolved Oxygen

    Science.gov (United States)

    Neilan, Rachael Miller

    2013-01-01

    This article describes a computational project designed for undergraduate students as an introduction to mathematical modeling. Students use an ordinary differential equation to describe fish weight and assume the instantaneous growth rate depends on the concentration of dissolved oxygen. Published laboratory experiments suggest that continuous…

  17. Assessment of chronic effects of tebuconazole on survival, reproduction and growth of Daphnia magna after different exposure times.

    Science.gov (United States)

    Sancho, E; Villarroel, M J; Ferrando, M D

    2016-02-01

    The effect of the fungicide tebuconazole (0.41, 0.52, 0.71 and 1.14mg/L) on survival, reproduction and growth of Daphnia magna organisms was monitored using 14 and 21 days exposure tests. A third experiment was performed by exposing D. magna to the fungicide for 14 days followed by 7 days of recovery (14+7). In order to test fungicide effects on D. magna, parameters as survival, mean whole body length, mean total number of neonates per female, mean number of broods per female, mean brood size per female, time to first brood/reproduction and intrinsic rate of natural increase (r) were used. Reproduction was seriously affected by tebuconazole. All tebuconazole concentrations tested affected the number of broods per female and day to first brood. At 14-days test, number of neonates per female and body size decreased by concentrations of tebuconazole higher than 0.52mg/L, whereas at 21-days test both parameters were affected at all the concentrations tested. Survival of the daphnids after 14 days fungicide exposure did not exhibited differences among experimental and control groups. In this experiment r value was reduced (in a 22%) when animals were exposed to concentrations of 0.71mg/L and 1.14mg/L. Survival of daphnids exposed during 21 days to 1.14mg/L declined, and the intrinsic rate of natural increase (r) decreased in a 30 % for tebuconazole concentrations higher than 0.41mg/L. Longevity of daphnids pre-exposed to tebuconazole for 14 days and 7 days in clean water did not show differences from control values and all of them survived the 21 days of the test. However, after 7 days in fungicide free medium animals were unable to restore control values for reproductive parameters and length. The maximum acceptable toxicant concentration (MATC) was calculated using the r values as parameter of evaluation. MATC estimations were 0.61mg/L and 0.46mg/L for 14 and 21 days, respectively. Results showed that the number of neonates per female was the highest sensitive

  18. Inositol-phosphate signaling as mediator for growth and sexual reproduction in Podospora anserina.

    Science.gov (United States)

    Xie, Ning; Ruprich-Robert, Gwenaël; Chapeland-Leclerc, Florence; Coppin, Evelyne; Lalucque, Hervé; Brun, Sylvain; Debuchy, Robert; Silar, Philippe

    2017-09-01

    The molecular pathways involved in the development of multicellular fruiting bodies in fungi are still not well known. Especially, the interplay between the mycelium, the female tissues and the zygotic tissues of the fruiting bodies is poorly documented. Here, we describe PM154, a new strain of the model ascomycetes Podospora anserina able to mate with itself and that enabled the easy recovery of new mutants affected in fruiting body development. By complete genome sequencing of spod1, one of the new mutants, we identified an inositol phosphate polykinase gene as essential, especially for fruiting body development. A factor present in the wild type and diffusible in mutant hyphae was able to induce the development of the maternal tissues of the fruiting body in spod1, but failed to promote complete development of the zygotic ones. Addition of myo-inositol in the growth medium was able to increase the number of developing fruiting bodies in the wild type, but not in spod1. Overall, the data indicated that inositol and inositol polyphosphates were involved in promoting fruiting body maturation, but also in regulating the number of fruiting bodies that developed after fertilization. The same effect of inositol was seen in two other fungi, Sordaria macrospora and Chaetomium globosum. Key role of the inositol polyphosphate pathway during fruiting body maturation appears thus conserved during the evolution of Sordariales fungi. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Bulk dynamics for interfacial growth models

    OpenAIRE

    Lopez, Cristobal; Garrido, Pedro L.; Santos, Francisco de los

    2000-01-01

    We study the influence of the bulk dynamics of a growing cluster of particles on the properties of its interface. First, we define a general bulk growth model by means of a continuum Master equation for the evolution of the bulk density field. This general model just considers an arbitrary addition of particles (though it can be easily generalized to consider subtraction) with no other physical restriction. The corresponding Langevin equation for this bulk density field is derived where the i...

  20. Impact of early season apical meristem injury by gall inducing tipworm (Diptera: Cecidomyiidae) on reproductive and vegetative growth of cranberry.

    Science.gov (United States)

    Tewari, S; Buonaccorsi, J P; Averill, A L

    2013-06-01

    Larvae of cranberry tipworm, Dasineura oxycoccana Johnson, disrupt early season growth of cranberry (Vaccinium macrocarpon Aiton) uprights or shoots by feeding on apical meristem tissue. A 2-yr field study was carried out at three different locations to determine the impact of tipworm feeding injury on the reproductive and vegetative growth of two cranberry cultivars ('Howes' and 'Stevens') in Massachusetts. In addition to tipworm-injured and intact control uprights, an artificial injury treatment simulating tipworm feeding was also included. Individual uprights of cranberry exhibited tolerance to natural (tipworm) and simulated apical meristem injury in the current growing season (fruit production) and results were corroborated by a greenhouse study. In the field study, weight of fruit was higher in tipworm-injured uprights as compared with intact control uprights at the sites with Howes. However, majority of injured uprights (tipworm and simulated) did not produce new growth from lateral buds (side-shoots) before the onset of dormancy. In the next growing season, fewer injured uprights resumed growth and produced flowers as compared with intact uprights at two of the three sites. We suggest that multiple-year studies focusing on whole plant response to tipworm herbivory will be required to determine the costs of chronic feeding injury over time.

  1. Dietary ractopamine supplementation during the first lactation affects milk composition, piglet growth and sow reproductive performance.

    Science.gov (United States)

    van Wettere, W H E J; Pain, S J; Hughes, P E

    2016-11-01

    Excessive mobilization of body reserves during lactation delays the return to reproductive function in weaned primiparous sows. This study tested the hypothesis that supplementing the lactation diets of first-parity sows with ractopamine hydrochloride would reduce maternal weight loss and improve subsequent reproductive performance. Gestating gilts were allocated to one of two treatment groups (n=30 sows/treatment), with one group fed a standard lactation diet (2.5g/Mcal LYS: DE) throughout lactation (CTRL), whereas the treatment group received the standard lactation diet supplemented with 10mg/kg ractopamine hydrochloride (RAC) from d 1 to 13 of lactation and 20mg/kg RAC from d 14 of lactation until artificial insemination (AI). Weaning occurred on d 21 of lactation, with AI occurring at the first post-weaning estrus. Compared to CTRL, RAC supplementation decreased (P<0.05) liveweight loss between d 13 and 20 of lactation (4.3±0.90 versus 1.3±0.96kg), and tended to increase (P=0.06) the number of second litter piglets born alive (9.5±0.52 versus 8.1±0.74). Treatment (RAC versus CTRL) reduced milk protein levels on d 13 and 20 of lactation (P<0.05), and piglet weight gain between d 13 and 20 of lactation (260±0.01 versus 310±0.01g/day, P<0.01). In conclusion, it is evident that dietary RAC altered milk composition and stimulated conservation of maternal body reserves during the third week of lactation, resulting in a beneficial effect on subsequent reproductive performance. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Does reproduction accelerate the growth of eye lens mass in female voles?

    Czech Academy of Sciences Publication Activity Database

    Jánová, Eva; Havelková, Dana; Tkadlec, Emil

    2007-01-01

    Roč. 137, č. 1 (2007), s. 85-88 ISSN 0777-6276 R&D Projects: GA ČR GA206/04/2003; GA ČR(CZ) GD524/05/H536 Institutional research plan: CEZ:AV0Z60930519 Keywords : age estimation * eye lens mass * reproduction Subject RIV: EH - Ecology, Behaviour Impact factor: 0.433, year: 2007 http://www.naturalsciences.be/institute/associations/rbzs_website/bjz/back/pdf/BJZ%20137(1)/Volume%20137(1),%20pp.%2085-88.pdf

  3. Successful survival, growth, and reproductive potential of quagga mussels in low calcium lake water: is there uncertainty of establishment risk?

    Directory of Open Access Journals (Sweden)

    Clinton J. Davis

    2015-11-01

    Full Text Available The risk of quagga mussel (Dreissena rostriformis bugensis Andrusov 1897 establishment into water-bodies of the western US has expanded the geographic concern regarding the ecological and economic impacts this species will have in aquatic ecosystems. Thresholds based on calcium concentrations, an element critical for mussel growth and physiology, have been used as a primary predictor of quagga mussel establishment success to aid management decisions. We evaluated the invasion potential of quagga mussels in low calcium waters using laboratory experiments to compare the survival, growth and reproductive potential of adult mussels held for 90 days at low (9 and 12 ppm, moderate (15 to 32 ppm and high (72 ppm calcium water concentrations. In conjunction with adult experiments, veliger stage survival, growth and settlement were evaluated under similar low, moderate, and high calcium water treatments. Adult mussels survived, grew and showed reproductive potential in low calcium water (12 ppm. Veligers were also able to survive, grow and settle in low calcium water. Higher levels of natural seston biomass appeared to improve adult mussel life history performance in low calcium water. Survival curve analysis predicted that 99% adult mortality could occur in 15 ppm could have adults surviving more than a year. The results from these bioassays provide further evidence that quagga mussels have higher risk of establishment in low calcium lakes if habitats exist that have slightly elevated calcium. These results should help emphasize the vulnerability of water-body in the 12 to 15 ppm calcium range that could potentially be at risk of establishing sustainable quagga mussel populations. Furthermore, these results provide insights into the uncertainty of using a single parameter in assigning establishment risk given the complexity of variables in specific water-bodies that influence life history performance of introduced species.

  4. Successful survival, growth, and reproductive potential of quagga mussels in low calcium lake water: is there uncertainty of establishment risk?

    Science.gov (United States)

    Davis, Clinton J; Ruhmann, Emma K; Acharya, Kumud; Chandra, Sudeep; Jerde, Christopher L

    2015-01-01

    The risk of quagga mussel (Dreissena rostriformis bugensis Andrusov 1897) establishment into water-bodies of the western US has expanded the geographic concern regarding the ecological and economic impacts this species will have in aquatic ecosystems. Thresholds based on calcium concentrations, an element critical for mussel growth and physiology, have been used as a primary predictor of quagga mussel establishment success to aid management decisions. We evaluated the invasion potential of quagga mussels in low calcium waters using laboratory experiments to compare the survival, growth and reproductive potential of adult mussels held for 90 days at low (9 and 12 ppm), moderate (15 to 32 ppm) and high (72 ppm) calcium water concentrations. In conjunction with adult experiments, veliger stage survival, growth and settlement were evaluated under similar low, moderate, and high calcium water treatments. Adult mussels survived, grew and showed reproductive potential in low calcium water (12 ppm). Veligers were also able to survive, grow and settle in low calcium water. Higher levels of natural seston biomass appeared to improve adult mussel life history performance in low calcium water. Survival curve analysis predicted that 99% adult mortality could occur in 15 ppm could have adults surviving more than a year. The results from these bioassays provide further evidence that quagga mussels have higher risk of establishment in low calcium lakes if habitats exist that have slightly elevated calcium. These results should help emphasize the vulnerability of water-body in the 12 to 15 ppm calcium range that could potentially be at risk of establishing sustainable quagga mussel populations. Furthermore, these results provide insights into the uncertainty of using a single parameter in assigning establishment risk given the complexity of variables in specific water-bodies that influence life history performance of introduced species.

  5. Effects of temperature on development, survival and reproduction of insects: Experimental design, data analysis and modeling

    Science.gov (United States)

    Jacques Regniere; James Powell; Barbara Bentz; Vincent Nealis

    2012-01-01

    The developmental response of insects to temperature is important in understanding the ecology of insect life histories. Temperature-dependent phenology models permit examination of the impacts of temperature on the geographical distributions, population dynamics and management of insects. The measurement of insect developmental, survival and reproductive responses to...

  6. Survival, growth and reproduction of non-native Nile tilapia II: fundamental niche projections and invasion potential in the northern Gulf of Mexico

    Science.gov (United States)

    Lowe, Michael R.; Wu, Wei; Peterson, Mark S.; Brown-Peterson, Nancy J.; Slack, William T.; Schofield, Pamela J.

    2012-01-01

    Understanding the fundamental niche of invasive species facilitates our ability to predict both dispersal patterns and invasion success and therefore provides the basis for better-informed conservation and management policies. Here we focus on Nile tilapia (Oreochromis niloticus Linnaeus, 1758), one of the most widely cultured fish worldwide and a species that has escaped local aquaculture facilities to become established in a coastal-draining river in Mississippi (northern Gulf of Mexico). Using empirical physiological data, logistic regression models were developed to predict the probabilities of Nile tilapia survival, growth, and reproduction at different combinations of temperature (14 and 30°C) and salinity (0–60, by increments of 10). These predictive models were combined with kriged seasonal salinity data derived from multiple long-term data sets to project the species' fundamental niche in Mississippi coastal waters during normal salinity years (averaged across all years) and salinity patterns in extremely wet and dry years (which might emerge more frequently under scenarios of climate change). The derived fundamental niche projections showed that during the summer, Nile tilapia is capable of surviving throughout Mississippi's coastal waters but growth and reproduction were limited to river mouths (or upriver). Overwinter survival was also limited to river mouths. The areas where Nile tilapia could survive, grow, and reproduce increased during extremely wet years (2–368%) and decreased during extremely dry years (86–92%) in the summer with a similar pattern holding for overwinter survival. These results indicate that Nile tilapia is capable of 1) using saline waters to gain access to other watersheds throughout the region and 2) establishing populations in nearshore, low-salinity waters, particularly in the western portion of coastal Mississippi.

  7. QSAR models for reproductive toxicity and endocrine disruption in regulatory use - a preliminary investigation

    DEFF Research Database (Denmark)

    Jensen, Gunde Egeskov; Niemela, J.R.; Wedebye, Eva Bay

    2008-01-01

    and epidemiological human studies), dominant lethal effect in rodents (in vivo) and Drosophila melanogaster sex-linked recessive lethal effect. A structure set of 57,014 European Inventory of Existing Chemical Substances (EINECS) chemicals was screened. A total of 5240 EINECS chemicals, corresponding to 9.2%, were...... predicted as reproductive toxicants by one or more of the models. The chemicals predicted positive for reproductive toxicity will be submitted to the Danish Environmental Protection Agency as scientific input for a future updated advisory classification list with advisory classifications for concern...

  8. Weed host specificity of the aphid, Aphis spiraecola: developmental and reproductive performance of aphids in relation to plant growth and leaf chemicals of the Siam weed, Chromolaena odorata.

    Science.gov (United States)

    Agarwala, B K; Das, Jhuma

    2012-01-01

    Density, distribution, and nutritional quality of plants are the causal basis of host plant selection in aphids. Nutritional qualities of a plant vary according to its growth stage and also in response to seasonal variation. How host plant growth stages shape aphid performance was studied in Aphis spiraecola Patch (Homoptera: Aphididae) on the perennial Siam weed, Chromolaena odorata (L.) King and Robinson (Asterales: Asteraceae). This plant species is the preferred host in the hot and humid tropical parts of northeast and southern India. Variations in developmental and reproductive performances in apterous viviparous female aphids were recorded in relation to differences in leaf chemicals in different growth stages of C. odorata. Aphids reproduced at higher rates in the vegetative stage of C. odorata when developmental time was shortest, and fecundity was higher in a longer reproductive time. Intrinsic rate of increase and net reproductive rate were also recorded to be higher in the vegetative stage of the weed host. In the vegetative stage, leaves contained higher quantity of proteins and nitrogen, which are vital for insect reproduction. Results of this study have demonstrated that A spiraecola showed synchronization of its developmental and reproductive performances to growth stages of C. odorata, which occur in high abundance in the study area.

  9. Reproductive/developmental toxicity and immunotoxicity assessment in the nonhuman primate model

    International Nuclear Information System (INIS)

    Buse, Eberhard; Habermann, Gunnar; Osterburg, Ingrid; Korte, Rainhart; Weinbauer, Gerhard F.

    2003-01-01

    Nonhuman primates are being used increasingly as a non-rodent animal model during preclinical toxicology and safety assessment on the basis of proven similarity and comparability between nonhuman primates and humans. The validity of the nonhuman primate models applies to many aspects of toxicological testing and holds particularly true for the evaluation of reproductive toxicology and developmental toxicology. More recently, the advent of humanized antibodies and vaccines imposed further demand on nonhuman primate models since many immunotherapeutics do not interact with rodent receptors but frequently only cross-react with primate tissue. In this paper we discuss the suitability of primate models for reproductive, developmental and immunotoxicology testing, and present our initial data on the development of lymphatic organs and immune system in a nonhuman primate model

  10. Mathematical foundations of the dendritic growth models.

    Science.gov (United States)

    Villacorta, José A; Castro, Jorge; Negredo, Pilar; Avendaño, Carlos

    2007-11-01

    At present two growth models describe successfully the distribution of size and topological complexity in populations of dendritic trees with considerable accuracy and simplicity, the BE model (Van Pelt et al. in J. Comp. Neurol. 387:325-340, 1997) and the S model (Van Pelt and Verwer in Bull. Math. Biol. 48:197-211, 1986). This paper discusses the mathematical basis of these models and analyzes quantitatively the relationship between the BE model and the S model assumed in the literature by developing a new explicit equation describing the BES model (a dendritic growth model integrating the features of both preceding models; Van Pelt et al. in J. Comp. Neurol. 387:325-340, 1997). In numerous studies it is implicitly presupposed that the S model is conditionally linked to the BE model (Granato and Van Pelt in Brain Res. Dev. Brain Res. 142:223-227, 2003; Uylings and Van Pelt in Network 13:397-414, 2002; Van Pelt, Dityatev and Uylings in J. Comp. Neurol. 387:325-340, 1997; Van Pelt and Schierwagen in Math. Biosci. 188:147-155, 2004; Van Pelt and Uylings in Network. 13:261-281, 2002; Van Pelt, Van Ooyen and Uylings in Modeling Dendritic Geometry and the Development of Nerve Connections, pp 179, 2000). In this paper we prove the non-exactness of this assumption, quantify involved errors and determine the conditions under which the BE and S models can be separately used instead of the BES model, which is more exact but considerably more difficult to apply. This study leads to a novel expression describing the BE model in an analytical closed form, much more efficient than the traditional iterative equation (Van Pelt et al. in J. Comp. Neurol. 387:325-340, 1997) in many neuronal classes. Finally we propose a new algorithm in order to obtain the values of the parameters of the BE model when this growth model is matched to experimental data, and discuss its advantages and improvements over the more commonly used procedures.

  11. Assessment of reproductive and growth performances of pig breeds in the peri-urban area of Douala (Equatorial Zone

    Directory of Open Access Journals (Sweden)

    J. Kouamo

    2015-06-01

    Full Text Available The aim of this study was to evaluate the reproductive and growth performances of pig breeds in Douala, Cameroon. The reproductive performance of gilts and multiparous sows (38 per group from 8 selected farms were monitored and controlled. Thereafter, piglets were controlled from birth to weaning age. The age at first service (AFS, fertility index (FI, fecundity, age at first farrowing (AFF, weight at first farrowing (WtFF and litter size (LS of gilts were 179.97 ± 25.40 days; 1.76 ± 0.77; 100 ± 0.00; 350.47 ± 40.58 days; 107.26 ± 31.85 kg and 7.18 ± 1.93 piglets, respectively. In sows, the FI, fecundity, LS and farrowing interval (FarI were 1.13 ± 0.34; 100 ± 0.00; 9.03 ± 2.14 piglets and 179.63 ± 25.14 days, respectively. FI and LS were better in sows compared to gilts (P = 0.000. The sex ratio was 0.63. Local breed animals reared in semi-modern farms and fed mixed feed showed the lowest WtFF. In piglets, the average birth weight (kg, the average weaning weight (kg, age at weaning (days and survival rate (% until weaning were 1.32 ± 0.20, 10.60 ± 1.41, 56.86 ± 8.24 and 48.43, respectively. These results indicated that reproductive performance is strongly influenced by breed, feed and farm type.

  12. Assessment of reproductive and growth performances of pig breeds in the peri-urban area of Douala (Equatorial Zone)

    Science.gov (United States)

    Kouamo, J.; Tankou, W.F. Tassemo; Zoli, A.P.; Bah, G.S.; Ongla, A.C. Ngo

    2015-01-01

    The aim of this study was to evaluate the reproductive and growth performances of pig breeds in Douala, Cameroon. The reproductive performance of gilts and multiparous sows (38 per group) from 8 selected farms were monitored and controlled. Thereafter, piglets were controlled from birth to weaning age. The age at first service (AFS), fertility index (FI), fecundity, age at first farrowing (AFF), weight at first farrowing (WtFF) and litter size (LS) of gilts were 179.97 ± 25.40 days; 1.76 ± 0.77; 100 ± 0.00; 350.47 ± 40.58 days; 107.26 ± 31.85 kg and 7.18 ± 1.93 piglets, respectively. In sows, the FI, fecundity, LS and farrowing interval (FarI) were 1.13 ± 0.34; 100 ± 0.00; 9.03 ± 2.14 piglets and 179.63 ± 25.14 days, respectively. FI and LS were better in sows compared to gilts (P = 0.000). The sex ratio was 0.63. Local breed animals reared in semi-modern farms and fed mixed feed showed the lowest WtFF. In piglets, the average birth weight (kg), the average weaning weight (kg), age at weaning (days) and survival rate (%) until weaning were 1.32 ± 0.20, 10.60 ± 1.41, 56.86 ± 8.24 and 48.43, respectively. These results indicated that reproductive performance is strongly influenced by breed, feed and farm type. PMID:26623369

  13. Modeling error distributions of growth curve models through Bayesian methods.

    Science.gov (United States)

    Zhang, Zhiyong

    2016-06-01

    Growth curve models are widely used in social and behavioral sciences. However, typical growth curve models often assume that the errors are normally distributed although non-normal data may be even more common than normal data. In order to avoid possible statistical inference problems in blindly assuming normality, a general Bayesian framework is proposed to flexibly model normal and non-normal data through the explicit specification of the error distributions. A simulation study shows when the distribution of the error is correctly specified, one can avoid the loss in the efficiency of standard error estimates. A real example on the analysis of mathematical ability growth data from the Early Childhood Longitudinal Study, Kindergarten Class of 1998-99 is used to show the application of the proposed methods. Instructions and code on how to conduct growth curve analysis with both normal and non-normal error distributions using the the MCMC procedure of SAS are provided.

  14. A tale of two morphs: modeling pollen transfer, magic traits, and reproductive isolation in parapatry.

    Science.gov (United States)

    Haller, Benjamin C; de Vos, Jurriaan M; Keller, Barbara; Hendry, Andrew P; Conti, Elena

    2014-01-01

    The evolution of the flower is commonly thought to have spurred angiosperm diversification. Similarly, particular floral traits might have promoted diversification within specific angiosperm clades. We hypothesize that traits promoting the precise positional transfer of pollen between flowers might promote diversification. In particular, precise pollen transfer might produce partial reproductive isolation that facilitates adaptive divergence between parapatric populations differing in their reproductive-organ positions. We investigate this hypothesis with an individual-based model of pollen transfer dynamics associated with heterostyly, a floral syndrome that depends on precise pollen transfer. Our model shows that precise pollen transfer can cause sexual selection leading to divergence in reproductive-organ positions between populations served by different pollinators, pleiotropically causing an increase in reproductive isolation through a "magic trait" mechanism. Furthermore, this increased reproductive isolation facilitates adaptive divergence between the populations in an unlinked, ecologically selected trait. In a different pollination scenario, however, precise pollen transfer causes a decrease in adaptive divergence by promoting asymmetric gene flow. Our results highlight the idea that magic traits are not "magic" in isolation; in particular, the effect size of magic traits in speciation depends on the external environment, and also on other traits that modify the strength of the magic trait's influence on non-random mating. Overall, we show that the evolutionary consequences of pollen transfer dynamics can depend strongly on the available pollinator fauna and on the morphological fit between flowers and pollinators. Furthermore, our results illustrate the potential importance of even weak reproductive isolating barriers in facilitating adaptive divergence.

  15. Flooding tolerance in cotton (gossypium hirsutum l.) at early vegetative and reproductive growth stages

    International Nuclear Information System (INIS)

    Hussain, A.

    2014-01-01

    Periodic flooding at any growth stage greatly affects growth and yield of crops. In order to develop flooding tolerant cotton cultivar and to identify the most sensitive growth stage to periodic flooding, a field experiment was conducted in which 60-cultivars/accessions/lines were subjected to two week flooding at seedling/early vegetative, flower and boll formation growth stages. Pre- and post-flooding soil analysis was also carried out. Nitrate-N was greatly reduced due to flooding applied at all growth stages, whereas NH4-N increased significantly. Similarly, Fe and Mn were also increased to many folds in flooded soils. Under hypoxic conditions, depletion of nitrates and toxic effects of accumulated NH4, Fe and Mn caused severe damages to cotton plants and even death of plants. Of the three growth stages, early vegetative growth stage is most sensitive to two week flooding. Flooding imposed at the flowering and boll formation growth stages caused a substantial amount of yield penalty. On the basis of survival percentage, the 60-cultivars/accessions/lines were categorized into tolerant (61%), moderately tolerant (31=60%) and sensitive (31%) to short term flooding. At the seedling or early vegetative growth stage, genotypes DPL-SR-2 followed by 124-F and MNH-427 were most tolerant to flooding, while AET-5, N-KRISHMA, LRA-5166, CEDIX and H-142 were ranked as sensitive to flooding stress. At the flowering stage, the genotype NIAB-92 followed by S-14 and MNH-427 were highly tolerant to flooding. At the boll formation stage, genotypes DPL-70010-N followed by GH-11-9-75 and B-2918-2 were highly tolerant waterlogging. More than 50% of the genotypes maintained the degree of flooding tolerance at three growth stages. However, on the basis of survival percentage at three growth stages, genotypes MNH-564, FH-114, MNH-786 and CIM-573 were included in the tolerant group and the genotypes N-KRISHMA, LRA-5166, CEDIX and H-142 were included in the sensitive group. These

  16. Modelling protocells the emergent synchronization of reproduction and molecular replication

    CERN Document Server

    Serra, Roberto

    2017-01-01

    The monograph discusses models of synthetic protocells, which are cell-like structures obtained from non-living matter endowed with some rudimentary kind of metabolism and genetics, but much simpler than biological cells. They should grow and proliferate, generating offsprings that resemble in some way the parent protocells with some variation, so that selection may take place. Sustainable protocell populations have not yet been obtained experimentally and mathematical models are therefore extremely important to address key questions concerning their synthesis and behavior. Different protocell “architectures” have been proposed and high-level abstract models like those that are presented in this book are particularly relevant to gain a better understanding of the different properites. These models are able to treat all the major dynamical phenomena in a unified framework, so they can be seen as “virtual laboratories” for protocell research. Particular attention is paid to the problem of synchronizatio...

  17. A three-stage discrete-time population model: continuous versus seasonal reproduction.

    Science.gov (United States)

    Ackleh, Azmy S; Dib, Youssef M; Jang, Sophia R-J

    2007-10-01

    We consider a three-stage discrete-time population model with density-dependent survivorship and time-dependent reproduction. We provide stability analysis for two types of birth mechanisms: continuous and seasonal. We show that when birth is continuous there exists a unique globally stable interior equilibrium provided that the inherent net reproductive number is greater than unity. If it is less than unity, then extinction is the population's fate. We then analyze the case when birth is a function of period two and show that the unique two-cycle is globally attracting when the inherent net reproductive number is greater than unity, while if it is less than unity the population goes to extinction. The two birth types are then compared. It is shown that for low birth rates the adult average number over a one-year period is always higher when reproduction is continuous. Numerical simulations suggest that this remains true for high birth rates. Thus periodic birth rates of period two are deleterious for the three-stage population model. This is different from the results obtained for a two-stage model discussed by Ackleh and Jang (J. Diff. Equ. Appl., 13, 261-274, 2007), where it was shown that for low birth rates seasonal breeding results in higher adult averages.

  18. Relative growth and reproductive cycle of the date mussel Lithophaga lithophaga (Linnaeus, 1758) sampled from the Bizerte Bay (Northern Tunisia)

    Science.gov (United States)

    Kefi, Ferdaous Jaafar; Boubaker, Samir; Menif, Najoua Trigui El

    2014-09-01

    Relative growth and the reproductive cycle of the date mussel Lithophaga lithophaga were studied from September 2002 to October 2003 in the Bizerte Bay (Northern Tunisia). Relationships between shell length and shell width, shell height as well as volume-related variables (shell dry weight, soft tissues dry weight and total wet weight) showed negative allometries in both sexes except for shell width in males (isometry) and shell height in both sexes (positive allometry). The sex ratio was unbalanced, within the length range of 6-48 mm, 49.43 % of the animals were males, 24.39 % females and 26.17 % sexually undifferentiated; within the length range of 49-92 mm, the respective values were 41.19, 52.7 and 6.1 %. Histological investigations as well as analyses of the condition index and the gonadosomatic index (CI and GSI) revealed the presence of a single reproductive cycle per year. Spawning occurred at the end of August and early September and was associated with a decrease in seawater temperature and salinity. A resting phase occurred in winter, coinciding with the lowest water temperatures. Histological examinations of the gonads of a total of 130 specimens revealed only two cases of hermaphroditism. The present study constitutes a useful baseline for a sustainable management of local wild stocks of L. lithophaga.

  19. Improved potato microclonal reproduction with the plant growth-promoting rhizobacteria Azospirillum

    OpenAIRE

    Tkachenko, Oksana V.; Evseeva, Nina V.; Boikova, Natalya V.; Matora, Larisa Yu.; Burygin, Gennady L.; Lobachev, Yuriy V.; Shchyogolev, Sergei Yu.

    2015-01-01

    International audience; AbstractMicroclonal propagation in vitro is being actively used in the production of healthy planting material of food and ornamental plants. However, it needs further improvement to increase the growth rates of microclones in vitro and enhance regenerant survivability ex vitro. A promising approach to this end could be inoculating in vitro-micropropagated plants with plant growth-promoting rhizobacteria, specifically Azospirillum. However, the influence of Azospirillu...

  20. Model of vascular desmoplastic multispecies tumor growth.

    Science.gov (United States)

    Ng, Chin F; Frieboes, Hermann B

    2017-10-07

    We present a three-dimensional nonlinear tumor growth model composed of heterogeneous cell types in a multicomponent-multispecies system, including viable, dead, healthy host, and extra-cellular matrix (ECM) tissue species. The model includes the capability for abnormal ECM dynamics noted in tumor development, as exemplified by pancreatic ductal adenocarcinoma, including dense desmoplasia typically characterized by a significant increase of interstitial connective tissue. An elastic energy is implemented to provide elasticity to the connective tissue. Cancer-associated fibroblasts (myofibroblasts) are modeled as key contributors to this ECM remodeling. The tumor growth is driven by growth factors released by these stromal cells as well as by oxygen and glucose provided by blood vasculature which along with lymphatics are stimulated to proliferate in and around the tumor based on pro-angiogenic factors released by hypoxic tissue regions. Cellular metabolic processes are simulated, including respiration and glycolysis with lactate fermentation. The bicarbonate buffering system is included for cellular pH regulation. This model system may be of use to simulate the complex interactions between tumor and stromal cells as well as the associated ECM and vascular remodeling that typically characterize malignant cancers notorious for poor therapeutic response. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Integrative rodent models for assessing male reproductive toxicity of environmental endocrine active substances

    Directory of Open Access Journals (Sweden)

    Jacques Auger

    2014-02-01

    Full Text Available In the present review, we first summarize the main benefits, limitations and pitfalls of conventional in vivo approaches to assessing male reproductive structures and functions in rodents in cases of endocrine active substance (EAS exposure from the postulate that they may provide data that can be extrapolated to humans. Then, we briefly present some integrated approaches in rodents we have recently developed at the organism level. We particularly focus on the possible effects and modes of action (MOA of these substances at low doses and in mixtures, real-life conditions and at the organ level, deciphering the precise effects and MOA on the fetal testis. It can be considered that the in vivo experimental EAS exposure of rodents remains the first choice for studies and is a necessary tool (together with the epidemiological approach for understanding the reproductive effects and MOA of EASs, provided the pitfalls and limitations of the rodent models are known and considered. We also provide some evidence that classical rodent models may be refined for studying the multiple consequences of EAS exposure, not only on the reproductive axis but also on various hormonally regulated organs and tissues, among which several are implicated in the complex process of mammalian reproduction. Such models constitute an interesting way of approaching human exposure conditions. Finally, we show that organotypic culture models are powerful complementary tools, especially when focusing on the MOA. All these approaches have contributed in a combinatorial manner to a better understanding of the impact of EAS exposure on human reproduction.

  2. Effects of sublethal chronic copper exposure on the growth and reproductive success of the Florida apple snail (Pomacea paludosa).

    Science.gov (United States)

    Rogevich, Emily C; Hoang, Tham C; Rand, Gary M

    2009-04-01

    Florida apple snails (Pomacea paludosa) were exposed to three concentrations of copper (Cu), in water (8 microg/L, 16 microg/L, 24 microg/L), for one generation to examine uptake and the effects on survival, growth, and reproduction of the F(0) generation and survival, growth, and whole body Cu of the F(1) generation. During a 9-month Cu exposure, apple snails exposed to 8-16 microg/L Cu had high Cu accumulation (whole body, foot, viscera, and shell) and significantly reduced clutch production (8-16 microg/L) and egg hatching (16 microg/L). Apple snails exposed to the 24 microg/L Cu had low survival and the treatment was therefore terminated. Concentrations of minerals (Na(+), K(+), Mg(2+), Ca(2+)) in tissues were maintained regardless of Cu exposure, but the distribution of Cu in the body of snails differed, depending on exposure concentrations. Higher exposure concentrations resulted in a greater percentage of Cu accumulated in the viscera of the snail. Copper exposure to the F(0) generation did not affect the survival, growth, or whole body Cu concentrations in the F(1) generation. These finding are significant, given the importance of the Florida apple snail in the Everglades food chain. Changes in the abundance of apple snail populations, as a result of Cu exposure, could ultimately affect foraging success of predators.

  3. Effects of culture conditions on the growth and reproduction of Gut Weed, Ulva intestinalis Linnaeus (Ulvales, Chlorophyta

    Directory of Open Access Journals (Sweden)

    Rapeeporn Ruangchuay

    2012-11-01

    Full Text Available In vitro cultivation of Gut Weed, Ulva intestinalis Linnaeus, was experimentally studied to support its near optimalfarming, with potential impact in Thailand on its direct use as human food or its co-cultures in shrimp farming.Germling clusters (2 weeks old and 7.50±2.98 mm long were seeded into 500 mL flasks and biomass growth rateoptimized with respect to the main controllable factors; seedling density, salinity, light intensity, and temperature. These factorswere assumed to each have an optimal value independent of the others, and the factors were optimized one at a time. Themaximum growth at three to four weeks of cultivation was obtained at the factor levels of 0.05 gL-1, 20 ppt, 80 mol photonm-2s-1 and 25°C. Early zoosporangia were obtained from 2nd to 4th weeks. The relative growth rate ranged from 9.47 to 22.18 %day-1, and only asexual reproduction of U. intestinalis was observed under these culture conditions.

  4. Vermicomposting of cattle and goat manures by Eisenia foetida and their growth and reproduction performance.

    Science.gov (United States)

    Loh, T C; Lee, Y C; Liang, J B; Tan, D

    2005-01-01

    Vermicomposting is commonly adopted for the treatment of livestock organic wastes. In the present study, two types of livestock manure were used for culturing of the earthworm, Eisenia foetida. Each treatment group consisted of six replicates and worm vermicasts were examined after 5 weeks. The concentrations of total C, P and K in goat manure vermicasts were higher than those in cattle manure vermicasts. Cattle vermicasts had a higher N content than goat vermicasts but the C:N ratio of fresh manure was higher than that of vermicasts for both materials. Earthworm biomass and reproductive performance, in terms of number of worms after 5 weeks of experiment, were higher in cattle manure than in goat manure. The cocoon production per worm in cattle manure was higher than in goat manure. However, the hatchability of cocoons was not affected by manure treatments. In conclusion, cattle manure provided a more nutritious and friendly environment to the earthworms than goat manure.

  5. Growth models for tree stems and vines

    Science.gov (United States)

    Bressan, Alberto; Palladino, Michele; Shen, Wen

    2017-08-01

    The paper introduces a PDE model for the growth of a tree stem or a vine. The equations describe the elongation due to cell growth, and the response to gravity and to external obstacles. An additional term accounts for the tendency of a vine to curl around branches of other plants. When obstacles are present, the model takes the form of a differential inclusion with state constraints. At each time t, a cone of admissible reactions is determined by the minimization of an elastic deformation energy. The main theorem shows that local solutions exist and can be prolonged globally in time, except when a specific ;breakdown configuration; is reached. Approximate solutions are constructed by an operator-splitting technique. Some numerical simulations are provided at the end of the paper.

  6. The effects of Copper and Zinc on survival, growth and reproduction of the cladoceran Daphnia longispina: introducing new data in an "old" issue.

    Science.gov (United States)

    Martins, Celso; Jesus, Fátima T; Nogueira, António J A

    2017-11-01

    Metal contamination is still a major environmental issue due to their continuous deposition and persistence. In this work we intended to assess the impact that Copper (Cu) and Zinc (Zn) exert in life-history parameters of Daphnia longispina, a common cladoceran in freshwater environments. Thus, we studied the effects of Cu (20-300 µg/L) and Zn (500-4000 µg/L) on the survival, growth, reproduction, feeding rate and population growth rate of D. longispina. Though survival was only reduced for the highest concentration of each metal, other endpoints were strongly affected by lower concentrations. Growth was affected by both metals, especially in the period 0-7 d, being significant for Cu ≥ 40 µg/L and Zn ≥ 500 µg/L. Indeed, growth endpoints at day 7 (body length and growth rate) were equally or more sensitive than the corresponding endpoints at day 21. The size at first reproduction decreased (significant for Cu ≥ 40 µg/L and Zn ≥ 500 µg/L). Reproduction decreased, which was partially explained by the reduced growth, but additional effects were supported by a direct effect of metals on reproduction (based on the relationship body length-brood size). Reduced growth and reproduction are likely a food mediated effect due to feeding inhibition caused by the metals. Globally, the studied endpoints were affected by Cu and Zn differently, supporting a chemical-specificity of the effects, with Zn causing more pronounced effects than Cu. This work presents an innovative approach to the effects of Cu and Zn to D. longispina, giving a general and comprehensive overview of those effects.

  7. Dendritic growth model of multilevel marketing

    Science.gov (United States)

    Pang, James Christopher S.; Monterola, Christopher P.

    2017-02-01

    Biologically inspired dendritic network growth is utilized to model the evolving connections of a multilevel marketing (MLM) enterprise. Starting from agents at random spatial locations, a network is formed by minimizing a distance cost function controlled by a parameter, termed the balancing factor bf, that weighs the wiring and the path length costs of connection. The paradigm is compared to an actual MLM membership data and is shown to be successful in statistically capturing the membership distribution, better than the previously reported agent based preferential attachment or analytic branching process models. Moreover, it recovers the known empirical statistics of previously studied MLM, specifically: (i) a membership distribution characterized by the existence of peak levels indicating limited growth, and (ii) an income distribution obeying the 80 - 20 Pareto principle. Extensive types of income distributions from uniform to Pareto to a "winner-take-all" kind are also modeled by varying bf. Finally, the robustness of our dendritic growth paradigm to random agent removals is explored and its implications to MLM income distributions are discussed.

  8. Sexual differentiation of the brain: a model for drug-induced alterations of the reproductive system

    International Nuclear Information System (INIS)

    Gorski, R.A.

    1986-01-01

    The process of the sexual differentiation of the brain represents a valuable model system for the study of the chemical modification of the mammalian brain. Although there are numerous functional and structural sex differences in the adult brain, these are imposed on an essentially feminine or bipotential brain by testicular hormones during a critical phase of perinatal development in the rat. It is suggested that a relatively marked structural sex difference in the rat brain, the sexually dimorphic nucleus of the preoptic area (SDN-POA), is a morphological signature of the permanent or organizational action of estradiol derived from the aromatization of testicular testosterone. The SDN-POA of the male rat is severalfold larger in volume and is composed of more neurons than that of the female. The observation that the mitotic formation of the neurons of the SDN-POA is specifically prolonged has enabled us to identify the time course and pathway of neuronal migration into the nucleus. Study of the development of the SDN-POA suggests that estradiol in the male increases the number of neurons which survive a phase of neuronal death by exerting a neurite growth promoting action and/or a direct neuronotrophic action. Finally, although it is clear that gonadal hormones have dramatic permanent effects on the brain during perinatal development, even after puberty and in adulthood gonadal steroids can alter neuronal structure and, perhaps as a corollary to this, have permanent effects on reproductive function. Although the brain may be most sensitive to gonadal hormones or exogenous chemical factors during perinatal development, such as sensitivity does not appear limited to this period

  9. Conceptual Model of Business Situation of Attraction and Reproduction of Temporary Personnel of the Event Service

    Directory of Open Access Journals (Sweden)

    Donets Oleksiy S.

    2014-01-01

    Full Text Available The article considers importance of formation of the acting system of personnel management, since personnel determines the competitive potential and competitive advantages of an organisation. It develops a cognitive model of a business situation, which helps to present the process of attraction and reproduction of temporary personnel at enterprises, which deal with organisation of large-scale events, and influence of the factors upon each other. It builds a conceptual model of a business situation of attraction and reproduction of temporary personnel of the event service and, on its basis, offers a model of decision making with the use of elements of fuzzy logic on selection of a specialist for a specific position. It allocates main characteristics of employees, which are taken into account when forming decisions regarding taking on a candidate.

  10. Growth models and analysis of development

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, G.

    1979-10-01

    This paper deals with remnants of neoclassical elements in Keynesian and post-Keynesian thought, and attempts to demonstrate that the elimination of these elements from our modes of thinking would not impoverish economic analysis as a means of solving real problems. In the Keynesian analysis the causation from investment to savings is exhibited in terms of income determination. When put in terms of a capital-theory model, the vector of savings is represented in two ways: real savings and counterpart real savings. The former coincides with the investment vector and the latter with the vector of consumption goods foregone for diverting resources towards equipment making. Thus the Keynesian causation in capital theory terms makes the concept of national savings as an independent variable redudant. The Robinsonian causation in a golden age with full employment and its reversal of direction in a steady state with non-employment are then considered. But in each of these, variables like rate of savings and output/capital ratio are found to be dormant variables. They are termed as null variables which, being of no account in both full-employment and unemployment situations, could, without loss, be deleted from the repertory of analytical tools. The Harrod formula of warranted rate of growth, when put in causal form, thus becomes a redundant portion of economics of growth. The real determinants of the growth rate and real wage rate on which the analysis of growth or of development should be based, are also depicted.

  11. Highly plastic resource allocation to growth and reproduction in females of an African annual fish

    Czech Academy of Sciences Publication Activity Database

    Vrtílek, Milan; Reichard, Martin

    2015-01-01

    Roč. 24, č. 4 (2015), s. 616-628 ISSN 0906-6691 R&D Projects: GA ČR(CZ) GAP506/11/0112 Keywords : Nothobranchius * compensatory growth * egg size * life history * diet restriction Subject RIV: EG - Zoology Impact factor: 2.052, year: 2015

  12. Modeling and control of greenhouse crop growth

    CERN Document Server

    Rodríguez, Francisco; Guzmán, José Luis; Ramírez-Arias, Armando

    2015-01-01

    A discussion of challenges related to the modeling and control of greenhouse crop growth, this book presents state-of-the-art answers to those challenges. The authors model the subsystems involved in successful greenhouse control using different techniques and show how the models obtained can be exploited for simulation or control design; they suggest ideas for the development of physical and/or black-box models for this purpose. Strategies for the control of climate- and irrigation-related variables are brought forward. The uses of PID control and feedforward compensators, both widely used in commercial tools, are summarized. The benefits of advanced control techniques—event-based, robust, and predictive control, for example—are used to improve on the performance of those basic methods. A hierarchical control architecture is developed governed by a high-level multiobjective optimization approach rather than traditional constrained optimization and artificial intelligence techniques.  Reference trajector...

  13. Reproduction of an animal model of landmine blast injuries

    Directory of Open Access Journals (Sweden)

    Sen ZHANG

    2014-03-01

    Full Text Available Objective To reproduce an animal model of landmine blast injuries for studying its mechanism and characteristics. Methods Fifteen healthy New Zealand white rabbits (body weight 1.9-2.4 kg were prepared as experimental animals. Punctiform burster was used to simulate the landmine, and it was electrically detonated far away to produce landmine blast injuries on unilateral hind limb of rabbits in upright state. The vital signs before and 5min, 15min, 30min, 45min, 1h, 2h, 3h, 6h, 9h and 12h after injuries were recorded. Autopsy of dead animals was performed immediately and the survivors were sacrificed for pathological examination 6h and 12h after the injury. Macroscopic and microscopic changes in the injured limb and distant organs were observed. Fifteen random adult body weights were generated by random number table, and the explosive energy of M14 landmine (about 29g TNT explosive energy was simulated, to compare the ratio of explosive force equivalent to weight calculated between experimental animals and randomly selected adults. Results No significant change in blood pressure was observed at different time points before and after injuries. A broom-like change was found in the injured limb by the general observation. The subareas and pathological changes of injured limb coincided with the typical limb injuries produced by landmine explosion. Damage in different degrees was found in distant organs, and the wound characteristics and injury of major organs were in accordance with the reports of relevant literature. The ratio of explosive equivalent to weight of experimental animals (0.50±0.04g TNT/kg was similar to that of randomly selected adults (0.51±0.05g TNT/kg. Conclusion The present animal model could simulate the landmine explosive injuries, and may be used in research of landmine explosive injuries. DOI: 10.11855/j.issn.0577-7402.2014.01.14

  14. Effect of feeding salt tolerant plants on growth and reproduction of goats

    International Nuclear Information System (INIS)

    Ali, M.; Khanum, S.A.; Naqvi, S.H.M.

    1991-01-01

    Two experiments were conducted to assess the reproductive performance of dwarf goats grazing on salt tolerant and other forages. In Experiment 1, eight female dwarf goats grouped into two treatments of four animals each were allowed to graze either kallar grass only or kallar grass and other salt tolerant forages. The protein content of kallar grass was below the critical level in winter (4.9%) and just above in the summer (8.8%). Its mineral contents were higher than the required level in all seasons. The other salt tolerant forages had higher protein and mineral contents than kallar grass. Animals restricted to kallar grass showed significant loss in liveweight only during winter; the difference between the two groups was not significant in autumn and summer. Conception rate and levels of progesterone and oestradiol 17β were normal in both groups. However, animals restricted to kallar grass only suffered from reduced lactation, abortion and mortality of their kids. In Experiment 2, twenty dwarf goats were allocated to two groups whereby one group had free access to salt tolerant forages and the other to normal forages at different sites. The oestrous cycles of the goats were synchronized by administering two intramuscular injections of 0.5 mL Estrumate 10 days apart. The pattern and concentrations of progesterone were assessed and no difference was observed between the two treatment groups. (author). 20 ref, 5 figs, 3 tabs

  15. A new model for sustainable growth in the energy industry

    International Nuclear Information System (INIS)

    McFaddin, S.; Clouse, M.

    1993-01-01

    A new sustainable growth model is developed which enables the evaluations of the interdependence of financial objectives, operational performance and sustainable growth in the energy industry. This new model includes both the effect of inflation and growth produced from equity issues. Component analysis is shown to be an extremely useful tool in determining the effect of operational and financial variables on the sustainable growth rate. This new model is statistically compared with both actual growth rates and Higgins' model. Implications of this research include a more accurate financial planning tool for evaluating sustainable growth and a more effective tool for directing policies to stimulate growth in specific industries. (author)

  16. Phenotype and genetic parameters for body measurements, reproductive traits and gut lenght of Nile tilapia (Oreochromis niloticus) selected for growth in low-input earthen ponds

    NARCIS (Netherlands)

    Charo-Karisa, H.; Bovenhuis, H.; Rezk, M.A.; Ponzoni, R.W.; Arendonk, van J.A.M.; Komen, J.

    2007-01-01

    In this study we present estimates of phenotypic and genetic parameters for body size measurements, reproductive traits, and gut length for Nile tilapia (Oreochromis niloticus) selected for growth in fertilized earthen ponds for two generations. Throughout the experiment, ponds were fertilized daily

  17. Growth and reproduction investment of the young of the year of the squat lobster Munida gregaria (Crustacea: Anomura in the Patagonian coast

    Directory of Open Access Journals (Sweden)

    Martin Varisco

    2015-09-01

    Full Text Available The growth and reproduction investment of the young of the year (0+ of the squat lobster Munida gregaria in San Jorge Gulf, Argentina, were analysed. Moult cycle and size frequency distribution were studied in monthly field samples. Experiments to determine moult increments and intermoult duration were conducted. Sexual maturity, fecundity and reproductive output were analysed in field samples. In addition, maturity experiments in laboratory cultures were conducted. After settlement (November, juveniles showed fast growth until winter (July and growth restarted in September-October. At the beginning of the mating period (early June, males 0+ exhibited mature gonads, whereas females 0+ only showed previtellogenic oocytes. Experimental data showed that females with developed gonads had smaller-size increments in the previous moult. Fecundity and reproductive output were significantly lower in females 0+ than in older females. The early life history of M. gregaria in San Jorge Gulf differs from that of southern populations as those of Beagle Channel and Strait of Magellan due to faster growth and early reproductive investment. Our results suggest that females 0+ of M. gregaria have two investment strategies: early maturity with low fecundity and delayed maturity with higher future fecundity.

  18. Modeling of multibranched crosslike crack growth

    International Nuclear Information System (INIS)

    Canessa, E.; Tanatar, B.

    1991-06-01

    Multibranched crosslike crack patterns formed in concentrically loaded square plates are studied in terms of fractal geometry, where the associated fractal dimension d f is calculated for their characterization. We apply simplest deterministic and stochastic approaches at a phenomenological level in an attempt to find generic features as guidelines for future experimental and theoretical work. The deterministic model for fracture propagation we apply, which is a variant of the discretized Laplace approach for randomly ramified fractal cracks proposed by Takayasu, reproduces the basic ingredients of observed complex fracture patters. The stochastic model, although is not strictly a model for crack propagation, is based on diffusion-limited aggregation (DLA) for fractal growth and produces slightly more realistic assessment of the crosslike growth of the cracks in asymmetric multibranches. Nevertheless, this simple ad-hoc DLA-version for modeling the present phenomena as well as the deterministic approach for fracture propagation give fractal dimensionality for the fracture pattern in accord with our estimations made from recent experimental data. It is found that there is a crossover of two fractal dimensions, corresponding to the core (higher d f ) and multibranched crosslike (lower D f ) regions, that contains loops, that are interpreted as representing different symmetry regions within the square plates of finite size. (author). 26 refs, 5 figs

  19. Assessing reproductive toxicity of two environmental toxicants with a novel in vitro human spermatogenic model

    Directory of Open Access Journals (Sweden)

    Charles A. Easley, IV

    2015-05-01

    Full Text Available Environmental influences and insults by reproductive toxicant exposure can lead to impaired spermatogenesis or infertility. Understanding how toxicants disrupt spermatogenesis is critical for determining how environmental factors contribute to impaired fertility. While current animal models are available, understanding of the reproductive toxic effects on human fertility requires a more robust model system. We recently demonstrated that human pluripotent stem cells can differentiate into spermatogonial stem cells/spermatogonia, primary and secondary spermatocytes, and haploid spermatids; a model that mimics many aspects of human spermatogenesis. Here, using this model system, we examine the effects of 2-bromopropane (2-BP and 1,2,dibromo-3-chloropropane (DBCP on in vitro human spermatogenesis. 2-BP and DBCP are non-endocrine disrupting toxicants that are known to impact male fertility. We show that acute treatment with either 2-BP or DBCP induces a reduction in germ cell viability through apoptosis. 2-BP and DBCP affect viability of different cell populations as 2-BP primarily reduces spermatocyte viability, whereas DBCP exerts a much greater effect on spermatogonia. Acute treatment with 2-BP or DBCP also reduces the percentage of haploid spermatids. Both 2-BP and DBCP induce reactive oxygen species (ROS formation leading to an oxidized cellular environment. Taken together, these results suggest that acute exposure with 2-BP or DBCP causes human germ cell death in vitro by inducing ROS formation. This system represents a unique platform for assessing human reproductive toxicity potential of various environmental toxicants in a rapid, efficient, and unbiased format.

  20. [Effects of microwave irradiation and electrostatic field on the survival, growth and reproduction of Moina mongolica Daday].

    Science.gov (United States)

    Zhao, Wen; Xu, Xian-Zhong; Jin, Dong; Hu, Yu-Cai

    2008-09-01

    The study showed that 2 450 MHz microwave irradiation for 35 seconds or more had significant death effects on Moina mongolica Daday. Short-term (less than 25 seconds) microwave irradiation could obviously increase the larvae number per clutch and the total fecundity over life span of the animal, with the highest fecundity under 10 seconds irradiation. Microwave irradiation could significantly prolong the life span (15.8-18 d) of M. mongolica. The short-term microwave irradiation had less effect on the development of larvae animal, but inhibited the adult growth to some degree. Impulse electromagnetic field could significantly increase the fecundity of M. mongolica, with the highest effect of 29 kV x cm(-1); while high-voltage electrostatic field had less effect on the reproduction of M. mongolica. Both high-voltage and impulse electrostatic fields had no remarkable effects on the development of larvae animal. High-voltage electrostatic field had less effect on the growth of adult animal; while impulse electromagnetic field had definite inhibition effect on it, and the inhibition effect was increased with increasing voltage.

  1. Successful reproduction of unmated Tropilaelaps mercedesae and its implication on mite population growth in Apis mellifera colonies

    Science.gov (United States)

    Highly hygienic colonies are known to reduce the reproductive potential of Varroa destructor. For Tropilaelaps mercedesae, information on how bee behavior may influence the mite’s reproductive potential is currently unknown. In this study, we assessed the influence of recapping on the reproduction o...

  2. Effects of nanotoxicity on female reproductivity and fetal development in animal models.

    Science.gov (United States)

    Sun, Jianling; Zhang, Qiu; Wang, Zhiping; Yan, Bing

    2013-04-29

    The extensive application of nanomaterials in industry, medicine and consumer products has raised concerns about their potential toxicity. The female population is particularly vulnerable and deserves special attention because toxicity in this group may impact both female reproductivity and fetal development. Mouse and zebrafish models each have their own unique features and studies using these models to examine the potential toxicity of various nanoparticles are compared and summarized in this review. Several nanoparticles exhibit detrimental effects on female reproductivity as well as fetal development, and these adverse effects are related to nanoparticle composition, surface modification, dose, exposure route and animal species. Limited studies on the mechanisms of nanotoxicity are also documented and reviewed herein.

  3. Effects of Nanotoxicity on Female Reproductivity and Fetal Development in Animal Models

    Directory of Open Access Journals (Sweden)

    Jianling Sun

    2013-04-01

    Full Text Available The extensive application of nanomaterials in industry, medicine and consumer products has raised concerns about their potential toxicity. The female population is particularly vulnerable and deserves special attention because toxicity in this group may impact both female reproductivity and fetal development. Mouse and zebrafish models each have their own unique features and studies using these models to examine the potential toxicity of various nanoparticles are compared and summarized in this review. Several nanoparticles exhibit detrimental effects on female reproductivity as well as fetal development, and these adverse effects are related to nanoparticle composition, surface modification, dose, exposure route and animal species. Limited studies on the mechanisms of nanotoxicity are also documented and reviewed herein.

  4. A Reproductive Threat-Based Model of Evolved Sex Differences in Jealousy

    OpenAIRE

    Brad J. Sagarin; D. Vaughn Becker; Rosanna E. Guadagno; Wayne W. Wilkinson; Lionel D. Nicastle

    2012-01-01

    Although heterosexual women and men consistently demonstrate sex differences in jealousy, these differences disappear among lesbians and gay men as well as among heterosexual women and men contemplating same-sex infidelities (infidelities in which the partner and rival are the same sex). Synthesizing these past findings, the present paper offers a reproductive threat-based model of evolved sex differences in jealousy that predicts that the sexes will differ only when the jealous perceivers' r...

  5. Daphnia as a model organism in limnology and aquatic biology: some aspects of its reproduction and development

    Directory of Open Access Journals (Sweden)

    Adam Petrusek

    2011-08-01

    Full Text Available Invertebrates comprise the overwhelming majority of all animal species - around 95% of described species, not including substantial cryptic variation. As it is an extremely diverse and heterogeneous group, research on various invertebrate taxa often follows parallel trajectories, with little interaction among experts on different groups. To promote sharing of knowledge within as well as across taxa, the International Society of Invertebrate Reproduction and Development (ISIRD was established in 1975 in Calicut, India. Since that time, the ISIRD has organised international conferences at three-year intervals where various aspects of invertebrate biology are presented and discussed, naturally with the focus on reproduction and development. Traditionally, marine invertebrate groups have been well represented at all ISIRD congresses, but freshwater invertebrates have often been relatively overlooked at these meetings. The 12th ISIRD congress took place between August 16 and 20, 2010 in Prague, the Czech Republic. Several different Czech institutions collaborated on the organisation of this meeting. As aquatic invertebrate research has a long tradition in the country, we decided to include a section dedicated to popular model organisms in aquatic ecology and evolutionary biology, the "water fleas", cladocerans of the genus Daphnia. The section entitled "Daphnia and other cladocerans as model organisms" was open to any aspects of cladoceran biology directly or indirectly related to their reproduction or development. Unfortunately, the timing of the Prague congress completely overlapped the triennial congress of the International Society of Theoretical and Applied Limnology (SIL in Cape Town, South Africa. This large meeting in a very attractive setting attracted many cladocerologists from all over the world, including Europe. Therefore, the Daphnia section of the Prague ISIRD meeting remained moderate in size, attracting 13 contributions (eight talks

  6. Modelling the effects of environmental and individual variability when measuring the costs of first reproduction

    Directory of Open Access Journals (Sweden)

    Barbraud, C.

    2004-06-01

    Full Text Available How do animals balance their investment in young against their own chances to survive and reproduce in the future? This life–history trade–off, referred to as the cost of reproduction (Williams, 1966, holds a central place in life–history theory (Roff, 1992; Stearns, 1992; McNamara & Houston, 1996. Because individuals can only acquire a limited amount of energy, reproduction and survival as well as current and future reproduction are considered as functions competing for the same resources. In this framework, individuals may optimise life–history decisions. If the reproductive effort in one year leads to a loss in future reproductive output through decreased adult survival or reduced fecundity, then the optimal effort in the current season is less than the effort that would maximize the number of offspring produced in that season (Charnov & Krebs, 1974. There are at least two kinds of factors likely to confound the measurement of the costs of reproduction in the wild. First, there could be differences in the amount of energy individuals acquire and allocate to various functions. This phenotypic heterogeneity can mask or exacerbate individual allocation patterns when trends are averaged across a population (Vaupel & Yashin, 1985; McDonald et al., 1996; Cam & Monnat, 2000. Second, there could be variations in resource availability affecting energy acquisition and allocation. Theoretical models examining the optimal phenotypic balance between reproduction and survival under variable breeding conditions have investigated the influence of environmental stochasticity on the cost of reproduction in birds (Erikstad et al., 1998; Orzack & Tuljapurkar, 2001. However, there is little empirical evidence supporting these theoretical models. Here, we present analysis of the influence of experience, but also of the differential effects of environmental and individual variation on survival and future breeding probability. We address the question of the

  7. Somatotropic Signaling: Trade-Offs Between Growth, Reproductive Development, and Longevity

    Science.gov (United States)

    Sun, Liou Y.; Longo, Valter

    2013-01-01

    Growth hormone (GH) is a key determinant of postnatal growth and plays an important role in the control of metabolism and body composition. Surprisingly, deficiency in GH signaling delays aging and remarkably extends longevity in laboratory mice. In GH-deficient and GH-resistant animals, the “healthspan” is also extended with delays in cognitive decline and in the onset of age-related disease. The role of hormones homologous to insulin-like growth factor (IGF, an important mediator of GH actions) in the control of aging and lifespan is evolutionarily conserved from worms to mammals with some homologies extending to unicellular yeast. The combination of reduced GH, IGF-I, and insulin signaling likely contributes to extended longevity in GH or GH receptor-deficient organisms. Diminutive body size and reduced fecundity of GH-deficient and GH-resistant mice can be viewed as trade-offs for extended longevity. Mechanisms responsible for delayed aging of GH-related mutants include enhanced stress resistance and xenobiotic metabolism, reduced inflammation, improved insulin signaling, and various metabolic adjustments. Pathological excess of GH reduces life expectancy in men as well as in mice, and GH resistance or deficiency provides protection from major age-related diseases, including diabetes and cancer, in both species. However, there is yet no evidence of increased longevity in GH-resistant or GH-deficient humans, possibly due to non-age-related deaths. Results obtained in GH-related mutant mice provide striking examples of mutations of a single gene delaying aging, reducing age-related disease, and extending lifespan in a mammal and providing novel experimental systems for the study of mechanisms of aging. PMID:23589828

  8. Fisheries-induced adaptive change in reproductive investment in North Sea plaice (Pleuronectes platessa)?

    NARCIS (Netherlands)

    Rijnsdorp, A.D.; Grift, R.E.; Kraak, S.B.M.

    2005-01-01

    Life history theory predicts that fishing may select for increased reproductive investment. A model of the reaction norm for reproductive investment in a capital breeder was developed to disentangle changes in reproductive investment from changes in growth rate in North Sea plaice (Pleuronectes

  9. Threshold Dynamics of a Huanglongbing Model with Logistic Growth in Periodic Environments

    Directory of Open Access Journals (Sweden)

    Jianping Wang

    2014-01-01

    Full Text Available We analyze the impact of seasonal activity of psyllid on the dynamics of Huanglongbing (HLB infection. A new model about HLB transmission with Logistic growth in psyllid insect vectors and periodic coefficients has been investigated. It is shown that the global dynamics are determined by the basic reproduction number R0 which is defined through the spectral radius of a linear integral operator. If R0 1, then the disease persists. Numerical values of parameters of the model are evaluated taken from the literatures. Furthermore, numerical simulations support our analytical conclusions and the sensitive analysis on the basic reproduction number to the changes of average and amplitude values of the recruitment function of citrus are shown. Finally, some useful comments on controlling the transmission of HLB are given.

  10. A HOPS Protein, MoVps41, Is Crucially Important for Vacuolar Morphogenesis, Vegetative Growth, Reproduction and Virulence in Magnaporthe oryzae

    Directory of Open Access Journals (Sweden)

    Xiaojie Zhang

    2017-06-01

    Full Text Available The homotypic fusion and protein sorting protein complex (HOPS is the first known tether complex identified in the endocytic system that plays a key role in promoting homotypic vacuolar fusion, vacuolar biogenesis and trafficking in a wide range of organisms, including plant and fungi. However, the exact influence of the HOPS complex on growth, reproduction and pathogenicity of the economically destructive rice blast fungus has not been investigated. In this study, we identified M. oryzae vacuolar protein sorting 41 (MoVps41 an accessory subunit of HOPS complex and used targeted gene deletion approach to evaluate its contribution to growth, reproduction and infectious life cycle of the rice blast fungus. Corresponding results obtained from this study showed that MoVps41 is required for optimum vegetative development of M. oryzae and observed that MoVps41 deletion mutant displayed defective vegetative growth. Our investigation further showed that MoVps41 deletion triggered vacuolar fragmentation, compromised membrane integrity and pathogenesis of the ΔMovps41 mutant. Our studies also showed for the first time that MoVps41 plays an essential role in the regulation of sexual and asexual reproduction of M. oryzae. In summary, our study provides insight into how MoVps41 mediated vacuolar fusion and biogenesis influences reproduction, pathogenesis, and vacuolar integrity in M. oryzae and also underscores the need to holistically investigate the HOPS complex in rice blast pathogen.

  11. Does inter-plant variation in sprouting time affect the growth/reproduction trade-off and herbivory in a tropical tree species?

    Directory of Open Access Journals (Sweden)

    Marcilio Fagundes

    Full Text Available ABSTRACT The timing of phenological events varies within and among populations, affecting the performance of individual plants differently. We evaluated the effects of relative variation in sprouting time on the display of reproductive events, vegetative growth and herbivory in Copaifera langsdorffii (Fabaceae. A total of 93 trees of C. langsdorffii was monitored daily to determine their sprouting time. We collected ten terminal branches of each plant to evaluate vegetative growth, production of defense compounds and insect herbivore damage. The sprouting time for the studied population lasted 67 days. Variation in sprouting time did not affect the probability of plants to enter the reproductive stage. Plants that entered the reproductive stage showed greater vegetative biomass. Variation in sprouting time had a negative relationship with branch growth and a positive relationship with the number of leaflets. Leaf phenol concentration did not vary in relation to sprouting time or plant phenology, but herbivory was higher in plants that sprouted later. The relationships among plant sprouting time, vegetative development and display of reproductive stage in C. langsdorffii are discussed. The results of this study also suggest that early sprouting prior to the rainy season is a strategy used by C. langsdorffii to escape herbivores attacks.

  12. Population Growth and Local Home Environment Externality in an Endogenous Growth Model with Two Engines of Growth

    OpenAIRE

    Shirou Kuwahara; Katsunori Yamada

    2007-01-01

    This paper presents an endogenous growth model with population growth and an inter-generational spillover of human capital: we consider the ``local home environment externality conceptualized by Galor and Tsiddon (1997a). The model will generate a negative relationship between the population growth rate and the per capita GDP growth rate, which is also present in the data. Furthermore, multiple equilibrium paths will result. As far as we know, this is the first paper that derives a multiplici...

  13. Effects of pesticides, polychlorinated biphenyls and metals on the growth and reproduction of Acanthamoeba castellanii

    Energy Technology Data Exchange (ETDEWEB)

    Prescott, L.M.; Kubovec, M.K.; Tryggestad, D.

    1977-07-01

    The effects of pollutants (pesticides, PCB and metals) were studied in the free-living amoeba, Acanthamoeba castellanii. Eight pesticides were used--the insecticides dieldrin, aldrin and sevin, and the herbicides linuron, stam F-34, IPC, atrazine and simazine. It was shown that the sensitivity of A. castellanii to pesticides varied greatly. The population growth was inhibited by linuron, stam F-34, IPC, sevin and atrazine at a level of 10 mg/l. The polychlorinated biphenyl, Arochor 1254, had no significant effect at a concentration of 0.01 mg/l (10 ppb). The studies with metal ions showed that A. castellanii was unaffected by moderately high levels of Cu and Zn, but was sensitive to the presence of Pb and mercuric ions.

  14. Natural and sexual selection giveth and taketh away reproductive barriers: models of population divergence in guppies.

    Science.gov (United States)

    Labonne, Jacques; Hendry, Andrew P

    2010-07-01

    The standard predictions of ecological speciation might be nuanced by the interaction between natural and sexual selection. We investigated this hypothesis with an individual-based model tailored to the biology of guppies (Poecilia reticulata). We specifically modeled the situation where a high-predation population below a waterfall colonizes a low-predation population above a waterfall. Focusing on the evolution of male color, we confirm that divergent selection causes the appreciable evolution of male color within 20 generations. The rate and magnitude of this divergence were reduced when dispersal rates were high and when female choice did not differ between environments. Adaptive divergence was always coupled to the evolution of two reproductive barriers: viability selection against immigrants and hybrids. Different types of sexual selection, however, led to contrasting results for another potential reproductive barrier: mating success of immigrants. In some cases, the effects of natural and sexual selection offset each other, leading to no overall reproductive isolation despite strong adaptive divergence. Sexual selection acting through female choice can thus strongly modify the effects of divergent natural selection and thereby alter the standard predictions of ecological speciation. We also found that under no circumstances did divergent selection cause appreciable divergence in neutral genetic markers.

  15. Estimating the basic reproduction rate of HFMD using the time series SIR model in Guangdong, China.

    Directory of Open Access Journals (Sweden)

    Zhicheng Du

    Full Text Available Hand, foot, and mouth disease (HFMD has caused a substantial burden of disease in China, especially in Guangdong Province. Based on notifiable cases, we use the time series Susceptible-Infected-Recovered model to estimate the basic reproduction rate (R0 and the herd immunity threshold, understanding the transmission and persistence of HFMD more completely for efficient intervention in this province. The standardized difference between the reported and fitted time series of HFMD was 0.009 (<0.2. The median basic reproduction rate of total, enterovirus 71, and coxsackievirus 16 cases in Guangdong were 4.621 (IQR: 3.907-5.823, 3.023 (IQR: 2.289-4.292 and 7.767 (IQR: 6.903-10.353, respectively. The heatmap of R0 showed semiannual peaks of activity, including a major peak in spring and early summer (about the 12th week followed by a smaller peak in autumn (about the 36th week. The county-level model showed that Longchuan (R0 = 33, Gaozhou (R0 = 24, Huazhou (R0 = 23 and Qingxin (R0 = 19 counties have higher basic reproduction rate than other counties in the province. The epidemic of HFMD in Guangdong Province is still grim, and strategies like the World Health Organization's expanded program on immunization need to be implemented. An elimination of HFMD in Guangdong might need a Herd Immunity Threshold of 78%.

  16. Maternal testosterone and reproductive outcome in a rat model of obesity.

    Science.gov (United States)

    Arnon, Liat; Hazut, Noa; Tabachnik, Tzlil; Weller, Aron; Koren, Lee

    2016-09-01

    Global sex differences in obesity rates are persistent, suggesting the involvement of sex steroids. In addition, adipose tissue is a metabolic site for steroidogenesis. Here, we compared female reproductive parameters in a rat model of obesity, with the same parameters in its lean control strain, and tested for an association with integrated measures of corticosterone and testosterone. Steroids were extracted and quantified from 17 Otsuka Long Evans Tokushima Fatty (OLETF; an animal model for obesity) and 13 Long Evans Tokushima Otsuka (LETO; the lean control strain) hair samples that were collected after weaning offspring. The obese OLETF mothers had higher hair testosterone levels than the control LETO strain. Overall, testosterone, but not corticosterone, predicted litter sex ratios. Younger mothers with large litters and older mothers with small litters tended to have the highest sex ratios (i.e., male-biased litters). In the lean LETO strain, but not in the obese OLETF, maternal testosterone was positively associated with litter size and number of male pups. Corticosterone did not differ between the two strains and was not associated with testosterone or with reproductive parameters. This study suggests that long-term circulating testosterone is associated with female reproduction in multiple ways. The possible trade-off between litter size and sex ratio may be mediated by testosterone and influenced by body fat and composition, which influence the individual's well-being. Exploring the multiple roles of testosterone in females may also help explain the complex relationship between obesity and reproduction. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Modeling of Organic Effects on Aerosols Growth

    Science.gov (United States)

    Caboussat, A.; Amundson, N. R.; He, J.; Seinfeld, J. H.

    2006-05-01

    Over the last two decades, a series of modules has been developed in the atmospheric modeling community to predict the phase transition, multistage growth phenomena, crystallization and evaporation of inorganic aerosols. In the same time, the water interactions of particles containing organic constituents have been recognized as an important factor for aerosol activation and cloud formation. However, the research on hygroscopicity of organic-containing aerosols, motivated by the organic effect on aerosol growth and activation, has gathered much less attention. We present here a new model (UHAERO), that is both efficient and rigorously computes phase separation and liquid-liquid equilibrium for organic particles, as well as the dynamics partitioning between gas and particulate phases, with emphasis on the role of water vapor in the gas-liquid partitioning. The model does not rely on any a priori specification of the phases present in certain atmospheric conditions. The determination of the thermodynamic equilibrium is based on the minimization of the Gibbs free energy. The mass transfer between the particle and the bulk gas phase is dynamically driven by the difference between bulk gas pressure and the gas pressure at the surface of a particle. The multicomponent phase equilibrium for a closed organic aerosol system at constant temperature and pressure and for specified feeds is the solution to the liquid-liquid equilibrium problem arising from the constrained minimization of the Gibbs free energy. A geometrical concept of phase simplex (phase separation) is introduced to characterize the thermodynamic equilibrium. The computation of the mass fluxes is achieved by coupling the thermodynamics of the organic aerosol particle and the determination of the mass fluxes. Numerical results show the efficiency of the model, which make it suitable for insertion in global three- dimensional air quality models. The Gibbs free energy is modeled by the UNIFAC model to illustrate

  18. A review of Red Queen models for the persistence of obligate sexual reproduction.

    Science.gov (United States)

    Lively, Curtis M

    2010-01-01

    I present a historical review of coevolutionary models for the evolutionary persistence of sexual reproduction. The focus is on the fate of obligately sexual populations facing competition with one or more obligately asexual clones. An early simulation model by Hamilton (Hamilton WD. 1980. Sex versus non-sex versus parasite. Oikos. 35:282-290.) suggested that parasites could be an important force in selecting against asexual clones, leading to the persistence of sex. This result was consistent with a number of independent verbal models generated from 1975-1983. Conversely, the models by May and Anderson (May RM, Anderson RM. 1983. Epidemiology and genetics in the coevolution of parasites and hosts. Proc R Soc Lond B Biol Sci. 219:281-313.), which included more epidemiological detail, suggested that parasites were an unlikely source of selection to favor sexual over asexual reproduction. Thus began an oscillation of opinion regarding the role of parasites in selection for sex. It would seem at present that some of the differences of opinion over time stemmed from the different ways that models were constructed, including whether the sexual population was in competition with a genetically diverse asexual population or a single clonal genotype. On theoretical grounds, parasite-mediated selection for sex seems more likely if the sexual population has options in genotypic space that are not available to the clones. Models that incorporate more ecological realism also seem more favorable to the parasite theory of sex.

  19. Reactive burn models and ignition & growth concept

    Science.gov (United States)

    Menikoff, R.; Shaw, M. S.

    Plastic-bonded explosives are heterogeneous materials. Experimentally, shock initiation is sensitive to small amounts of porosity, due to the formation of hot spots (small localized regions of high temperature). This leads to the Ignition & Growth concept, introduced by LeeTarver in 1980, as the basis for reactive burn models. A homo- genized burn rate needs to account for three meso-scale physical effects: (i) the density of active hot spots or burn centers; (ii) the growth of the burn fronts triggered by the burn centers; (iii) a geometric factor that accounts for the overlap of deflagration wavelets from adjacent burn centers. These effects can be combined and the burn model defined by specifying the reaction progress variable λ = g(s) as a function of a dimensionless reaction length s(t) = rbc/ℓbc, rather than by specifying an explicit burn rate. The length scale ℓbc(Ps) = [Nbc(Ps)]-1/3 is the average distance between burn centers, where Nbc is the number density of burn centers activated by the lead shock. The reaction length rbc(t) = ∫t0 D(P(t'))dt' is the distance the burn front propagates from a single burn center, where D(P) is the deflagration speed as a function of the local pressure and t is the time since the shock arrival. A key implementation issue is how to determine the lead shock strength in conjunction with a shock capturing scheme. We have developed a robust algorithm for this purpose based on the Hugoniot jump condition for the energy. The algorithm utilizes the time dependence of density, pressure and energy within each cell. The method is independent of the numerical dissipation used for shock capturing. It is local and can be used in one or more space dimensions. The burn model has a small number of parameters which can be calibrated to fit velocity gauge data from shock initiation experiments.

  20. Langevin equations for competitive growth models.

    Science.gov (United States)

    Silveira, F A; Aarão Reis, F D A

    2012-01-01

    Langevin equations for several competitive growth models in one dimension are derived. For models with crossover from random deposition (RD) to some correlated deposition (CD) dynamics, with small probability p of CD, the surface tension ν and the nonlinear coefficient λ of the associated equations have linear dependence on p due solely to this random choice. However, they also depend on the regularized step functions present in the analytical representations of the CD, whose expansion coefficients scale with p according to the divergence of local height differences when p→0. The superposition of those scaling factors gives ν~p(2) for random deposition with surface relaxation (RDSR) as the CD, and ν~p, λ~p(3/2) for ballistic deposition (BD) as the CD, in agreement with simulation and other scaling approaches. For bidisperse ballistic deposition (BBD), the same scaling of RD-BD model is found. The Langevin equation for the model with competing RDSR and BD, with probability p for the latter, is also constructed. It shows linear p dependence of λ, while the quadratic dependence observed in previous simulations is explained by an additional crossover before the asymptotic regime. The results highlight the relevance of scaling of the coefficients of step function expansions in systems with steep surfaces, which is responsible for noninteger exponents in some p-dependent stochastic equations, and the importance of the physical correspondence of aggregation rules and equation coefficients. © 2012 American Physical Society

  1. A daily herd Markov-chain model to study the reproductive and economic impact of reproductive programs combining timed artificial insemination and estrus detection.

    Science.gov (United States)

    Giordano, J O; Kalantari, A S; Fricke, P M; Wiltbank, M C; Cabrera, V E

    2012-09-01

    Our objective was to compare the economic and reproductive performance of programs combining timed artificial insemination (TAI) and different levels of AI after estrus detection (ED) using a daily Markov-chain model. A dairy herd was modeled with every cow following daily probabilistic events of aging, replacement, mortality, pregnancy, pregnancy loss, and calving. The probability of pregnancy depended on the combination of probability of insemination and conception rate (CR). All nonpregnant cows had a probability of pregnancy between the end of the voluntary waiting period and days in milk cutoff for AI. After the cutoff, cows were labeled as do not breed and replaced when milk production was below a minimum milk threshold. A similar model was created to represent a replacement heifer herd to simulate and adjust the supply and demand of replacements. The net value (NV) of a program was the sum of milk income over feed cost, replacement and mortality cost, income from newborns, and reproductive costs. The model was used to compare the NV of 19 programs. One program used 100% TAI (42% CR for first TAI and 30% for second-and-later services), whereas the other programs combined TAI with ED. The proportion of cows receiving AI after ED for the combined programs ranged from 30 to 80%, with levels of CR of 25, 30, and 35%. As the proportion of cows receiving AI after ED increased, the CR of cows receiving TAI decreased. The combined programs with CR of 35% for cows receiving AI after ED had the greatest NV and reproductive performance at all levels of ED. The program using 100% TAI had greater NV and better reproductive performance than all programs with 25% CR after ED inseminations, whereas it had very similar performance to combined programs with up to 60% of cows receiving AI after ED and 30% CR. The factor with the greatest relative contribution to the differences among programs was income over feed cost, followed by replacement and reproductive costs. Adjusting

  2. Improved estimates of age, growth and reproduction for the regionally endemic Galapagos sailfin grouper Mycteroperca olfax (Jenyns, 1840).

    Science.gov (United States)

    Usseglio, Paolo; Friedlander, Alan M; DeMartini, Edward E; Schuhbauer, Anna; Schemmel, Eva; Salinas de Léon, Pelayo

    2015-01-01

    The Galapagos Sailfin grouper, Mycteroperca olfax, locally known as bacalao and listed as vulnerable by the IUCN, is culturally, economically, and ecologically important to the Galapagos archipelago and its people. It is regionally endemic to the Eastern Tropical Pacific, and, while an important fishery resource that has shown substantial declines in recent years, to date no effective management regulations are in place to ensure the sustainability of the Galapagos fishery for this species. Previous estimates of longevity and size at maturity for bacalao are inconsistent with estimates for congeners, which brings into question the accuracy of prior estimates. We set out to assess the age, growth, and reproductive biology of bacalao in order to provide more accurate life history information to inform more effective fisheries management for this species. The oldest fish in our sample was 21 years old, which is 2-3 times greater than previously reported estimates of longevity. Parameter estimates for the von Bertalanffy growth function (k = 0.11, L ∞ = 110 cm TL, and to = - 1.7 years) show bacalao to grow much slower and attain substantially larger asymptotic maximum length than previous studies. Mean size at maturity (as female) was estimated at 65.3 cm TL, corresponding to a mean age of 6.5 years. We found that sex ratios were extremely female biased (0.009 M:1F), with a large majority of the individuals in our experimental catch being immature (79%). Our results show that bacalao grow slower, live longer, and mature at a much larger size and greater age than previously thought, with very few mature males in the population. These findings have important implications for the fishery of this valuable species and provide the impetus for a long-overdue species management plan to ensure its long-term sustainability.

  3. Improved estimates of age, growth and reproduction for the regionally endemic Galapagos sailfin grouper Mycteroperca olfax (Jenyns, 1840

    Directory of Open Access Journals (Sweden)

    Paolo Usseglio

    2015-09-01

    Full Text Available The Galapagos Sailfin grouper, Mycteroperca olfax, locally known as bacalao and listed as vulnerable by the IUCN, is culturally, economically, and ecologically important to the Galapagos archipelago and its people. It is regionally endemic to the Eastern Tropical Pacific, and, while an important fishery resource that has shown substantial declines in recent years, to date no effective management regulations are in place to ensure the sustainability of the Galapagos fishery for this species. Previous estimates of longevity and size at maturity for bacalao are inconsistent with estimates for congeners, which brings into question the accuracy of prior estimates. We set out to assess the age, growth, and reproductive biology of bacalao in order to provide more accurate life history information to inform more effective fisheries management for this species. The oldest fish in our sample was 21 years old, which is 2–3 times greater than previously reported estimates of longevity. Parameter estimates for the von Bertalanffy growth function (k = 0.11, L∞ = 110 cm TL, and to = − 1.7 years show bacalao to grow much slower and attain substantially larger asymptotic maximum length than previous studies. Mean size at maturity (as female was estimated at 65.3 cm TL, corresponding to a mean age of 6.5 years. We found that sex ratios were extremely female biased (0.009 M:1F, with a large majority of the individuals in our experimental catch being immature (79%. Our results show that bacalao grow slower, live longer, and mature at a much larger size and greater age than previously thought, with very few mature males in the population. These findings have important implications for the fishery of this valuable species and provide the impetus for a long-overdue species management plan to ensure its long-term sustainability.

  4. A survey of basic reproductive ratios in vector-borne disease transmission modeling

    Science.gov (United States)

    Soewono, E.; Aldila, D.

    2015-03-01

    Vector-borne diseases are commonly known in tropical and subtropical countries. These diseases have contributed to more than 10% of world infectious disease cases. Among the vectors responsible for transmitting the diseases are mosquitoes, ticks, fleas, flies, bugs and worms. Several of the diseases are known to contribute to the increasing threat to human health such as malaria, dengue, filariasis, chikungunya, west nile fever, yellow fever, encephalistis, and anthrax. It is necessary to understand the real process of infection, factors which contribute to the complication of the transmission in order to come up with a good and sound mathematical model. Although it is not easy to simulate the real transmission process of the infection, we could say that almost all models have been developed from the already long known Host-Vector model. It constitutes the main transmission processes i.e. birth, death, infection and recovery. From this simple model, the basic concepts of Disease Free and Endemic Equilibria and Basic Reproductive Ratio can be well explained and understood. Theoretical, modeling, control and treatment aspects of disease transmission problems have then been developed for various related diseases. General construction as well as specific forms of basic reproductive ratios for vector-borne diseases are discusses here.

  5. Parthenium weed (Parthenium hysterophorus L.) and climate change: the effect of CO2 concentration, temperature, and water deficit on growth and reproduction of two biotypes.

    Science.gov (United States)

    Nguyen, Thi; Bajwa, Ali Ahsan; Navie, Sheldon; O'Donnell, Chris; Adkins, Steve

    2017-04-01

    Climate change will have a considerable impact upon the processes that moderate weed invasion, in particular to that of parthenium weed (Parthenium hysterophorus L.). This study evaluated the performance of two Australian biotypes of parthenium weed under a range of environmental conditions including soil moisture (100 and 50% of field capacity), atmospheric carbon dioxide (CO 2 ) concentration (390 and 550 ppm), and temperature (35/20 and 30/15 °C/day/night). Measurements were taken upon growth, reproductive output, seed biology (fill, viability and dormancy) and soil seed longevity. Parthenium weed growth and seed output were significantly increased under the elevated CO 2 concentration (550 ppm) and in the cooler (30/15 °C) and wetter (field capacity) conditions. However, elevated CO 2 concentration could not promote growth or seed output when the plants were grown under the warmer (35/20 °C) and wetter conditions. Warm temperatures accelerated the growth of parthenium weed, producing plants with greater height biomass but with a shorter life span. Warm temperatures also affected the reproductive output by promoting both seed production and fill, and promoting seed longevity. Dryer soil conditions (50% of field capacity) also promoted the reproductive output, but did not retain high seed fill or promote seed longevity. Therefore, the rising temperatures, the increased atmospheric CO 2 concentration and the longer periods of drought predicted under climate change scenarios are likely to substantially enhance the growth and reproductive output of these two Australian parthenium weed biotypes. This may facilitate the further invasion of this noxious weed in tropical and sub-tropical natural and agro-ecosystems.

  6. The A Theory Of Magnitude (ATOM) model in temporal perception and reproduction tasks.

    Science.gov (United States)

    Fabbri, Marco; Cancellieri, Jennifer; Natale, Vincenzo

    2012-01-01

    According to the A Theory of Magnitude (ATOM) model, time, numbers and space are processed by a common analog magnitude system. The model proposes that time, numbers and space are influenced by each other. Indeed, spatial-temporal (STEARC effect), spatial-numerical (SNARC effect) and temporal-numerical (TiNARC effect) interactions have been observed. However, the processing of time, numbers and space has not yet been studied within the same experimental procedure. The goal of this study is to test the ATOM model using a procedure in which time, numbers and space are all present. The participants were asked to perform temporal estimation (Experiment 1) and reproduction (Experiment 2) tasks in two different conditions, with either numbers or letters as stimuli. In Experiment 1, significant STEARC, SNARC and TiNARC effects were found in general and when numbers were presented. Moreover, a significant triple interaction between space, time and magnitude was observed, indicating associations between the left key, short duration and small magnitudes, as well as between the right key, long duration and large magnitudes. These results were similar in reaction times and accuracy. In Experiment 2, the results of reproduction times mirrored the previous data but the triple interaction was not found on reproduction times. Considering the temporal accuracy, the STEARC, SNARC and TiNARC effects as well as triple interaction were found. The results seem to partially confirm the ATOM model, even if differences between temporal tasks should be posited. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Effects of development mode, contaminated sediments, and maternal characteristics on growth and reproduction in the polychaetes Streblospio benedicti (Spionidae) and Capitella sp. I (Capitellidae)

    Energy Technology Data Exchange (ETDEWEB)

    Bridges, T.S.

    1992-01-01

    Experiments were conducted to examine the effects of contaminated sediments (sewage, blue-green algae and hydrocarbons) and maternal characteristics on reproduction, and offspring success in S. benedicti (lecithotrophic) and Capitella sp. I. For S. benedicti, contaminated sediments had a negative effect on growth and age and size at first reproduction. Per brood fecundity was positively related to female size and negatively related to female age. Treatments did not have an effect on reproductive output. Per offspring C and N investment increased with female age. This increase in per offspring investment resulted in enhanced survivorship and juvenile growth in offspring of older females. For Capitella sp. I, growth was increased, age at first reproduction was accelerated, and per brood fecundity was 3--4 [times] higher in the algae and sewage treatments. Treatments did not have an effect on reproductive output. Fecundity was positively related to female size. Per brood and per offspring C and N investment decreased with female age, but not in all treatments. The C:N ratio of offspring increased with female age. Offspring from mothers in the sewage treatment were larger two weeks after release. Offspring in size two weeks after release decreased with female age in the sewage treatment. Differences in the response of S. benedicti and Capitella sp. I to contaminated sediments may be due to differences in feeding behavior, digestive physiology, nutritional requirements and their sensitivity to hydrocarbons, metals and low oxygen concentrations. Differences in the effect of female age between the two species appear related to development and ecological differences in the two species.

  8. Modeling urban growth in Kigali city Rwanda | Nduwayezu ...

    African Journals Online (AJOL)

    Modeling urban growth in Kigali city Rwanda. ... The uncontrolled urban growth is the key characteristics in most cities in less developed countries. However ... Models built, will help to better understand the dynamics of built-up area and guide sustainable urban development planning of the future urban growth in Kigali city.

  9. 4D Shape-Preserving Modelling of Bone Growth

    DEFF Research Database (Denmark)

    Andresen, Per Rønsholt; Nielsen, Mads; Kreiborg, Sven

    1998-01-01

    From a set of temporally separated scannings of the same anatomical structure we wish to identify and analyze the growth in terms of a metamorphosis. That is, we study the tempral change of shape which may prowide an understanding of the biological processes which govern the growth process. We...... subdivide the growth analysis into growth simulation, growth modelling, and finally the growth analysis. In this paper, we present results of growth simulation of the mandible from 3 scannings of the same patient in the age of 9 months, 21 months, and 7 years. We also present the first growth models...... and growth analyzes. The ultimative goal is to predict/simulate human growth which would be extremely useful in many surgical procedures....

  10. Geographic parthenogenesis in a consumer-resource model for sexual reproduction.

    Science.gov (United States)

    Song, Yixian; Scheu, Stefan; Drossel, Barbara

    2011-03-21

    The phenomenon of geographic parthenogenesis is closely tied to the question of why sexual reproduction is the dominant mode of reproduction in animals and plants. Geographic parthenogenesis describes the fact that many species reproduce asexually at the boundaries of their range. We present a mathematical model that derives the dominance of sexuals at the center and the dominance of asexuals at the boundary of a species' range from exactly the same mechanism. Our model is based on a set of resources that regrow slowly and that can be consumed only by those individuals that have a suitable genotype. Genotype is implemented by a multilocus model with two alleles at each locus, and with free recombination during production of sexual offspring. The model is tailored to seasonal species with intermittent mixis and low survival of offspring, such as Daphnia and aphids. Several patches of resources are arranged in a row, with a gradient of those parameters that typically vary through the range of species. By letting sexually and asexually reproducing populations compete, we obtain the typical patterns of geographic parthenogenesis. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. Mating behavior, population growth, and the operational sex ratio: a periodic two-sex model approach.

    Science.gov (United States)

    Jenouvrier, Stéphanie; Caswell, Hal; Barbraud, Christophe; Weimerskirch, Henri

    2010-06-01

    We present a new approach to modeling two-sex populations, using periodic, nonlinear two-sex matrix models. The models project the population growth rate, the population structure, and any ratio of interest (e.g., operational sex ratio). The periodic formulation permits inclusion of highly seasonal behavioral events. A periodic product of the seasonal matrices describes annual population dynamics. The model is nonlinear because mating probability depends on the structure of the population. To study how the vital rates influence population growth rate, population structure, and operational sex ratio, we used sensitivity analysis of frequency-dependent nonlinear models. In nonlinear two-sex models the vital rates affect growth rate directly and also indirectly through effects on the population structure. The indirect effects can sometimes overwhelm the direct effects and are revealed only by nonlinear analysis. We find that the sensitivity of the population growth rate to female survival is negative for the emperor penguin, a species with highly seasonal breeding behavior. This result could not occur in linear models because changes in population structure have no effect on per capita reproduction. Our approach is applicable to ecological and evolutionary studies of any species in which males and females interact in a seasonal environment.

  12. REFERENCE MODELS OF ENDOGENOUS ECONOMIC GROWTH

    OpenAIRE

    GEAMĂNU MARINELA

    2012-01-01

    The new endogenous growth theories are a very important research area for shaping the most effective policies and long term sustainable development strategies. Endogenous growth theory has emerged as a reaction to the imperfections of neoclassical theory, by the fact that the economic growth is the endogenous product of an economical system.

  13. Modelling asymmetric growth in crowded plant communities

    DEFF Research Database (Denmark)

    Damgaard, Christian

    2010-01-01

    -asymmetric growth part, where growth is assumed to be proportional to a power function of the size of the individual, and a term that reduces the relative growth rate as a decreasing function of the individual plant size and the competitive interactions from other plants in the neighbourhood....

  14. A model of urban rational growth based on grey prediction

    Science.gov (United States)

    Xiao, Wenjing

    2017-04-01

    Smart growth focuses on building sustainable cities, using compact development to prevent urban sprawl. This paper establishes a series of models to implement smart growth theories into city design. Besides two specific city design cases are shown. Firstly, We establishes Smart Growth Measure Model to measure the success of smart growth of a city. And we use Full Permutation Polygon Synthetic Indicator Method to calculate the Comprehensive Indicator (CI) which is used to measure the success of smart growth. Secondly, this paper uses the principle of smart growth to develop a new growth plan for two cities. We establish an optimization model to maximum CI value. The Particle Swarm Optimization (PSO) algorithm is used to solve the model. Combined with the calculation results and the specific circumstances of cities, we make their the smart growth plan respectively.

  15. Reactive burn models and ignition & growth concept

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph S [Los Alamos National Laboratory; Shaw, Milton S [Los Alamos National Laboratory

    2010-01-01

    Plastic-bonded explosives are heterogeneous materials. Experimentally, shock initiation is sensitive to small amounts of porosity, due to the formation of hot spots (small localized regions of high temperature). This leads to the Ignition and Growth concept, introduced by Lee and Tarver in 1980, as the basis for reactive burn models. A homogeneized burn rate needs to account for three mesoscale physical effects (i) the density of burnt hot spots, which depends on the lead shock strength; (ii) the growth of the burn fronts triggered by hot spots, which depends on the local deflagration speed; (iii) a geometric factor that accounts for the overlap of deflagration wavelets from adjacent hot spots. These effects can be combined and the burn model defined by specifying the reaction progress variable {lambda}(t) as a function of a dimensionless reaction length {tau}{sub hs}(t)/{ell}{sub hs}, rather than by xpecifying an explicit burn rate. The length scale {ell}{sub hs} is the average distance between hot spots, which is proportional to [N{sub hs}(P{sub s})]{sup -1/3}, where N{sub hs} is the number density of hot spots activated by the lead shock. The reaction length {tau}{sub hs}(t) = {line_integral}{sub 0}{sup t} D(P(t'))dt' is the distance the burn front propagates from a single hot spot, where D is the deflagration speed and t is the time since the shock arrival. A key implementation issue is how to determine the lead shock strength in conjunction with a shock capturing scheme. They have developed a robust algorithm for this purpose based on the Hugoniot jump condition for the energy. The algorithm utilizes the time dependence of density, pressure and energy within each cell. The method is independent of the numerical dissipation used for shock capturing. It is local and can be used in one or more space dimensions. The burn model has a small number of parameters which can be calibrated to fit velocity gauge data from shock initiation experiments.

  16. Reactive burn models and ignition & growth concept

    Directory of Open Access Journals (Sweden)

    Shaw M.S.

    2011-01-01

    Full Text Available Plastic-bonded explosives are heterogeneous materials. Experimentally, shock initiation is sensitive to small amounts of porosity, due to the formation of hot spots (small localized regions of high temperature. This leads to the Ignition & Growth concept, introduced by LeeTarver in 1980, as the basis for reactive burn models. A homo- genized burn rate needs to account for three meso-scale physical effects: (i the density of active hot spots or burn centers; (ii the growth of the burn fronts triggered by the burn centers; (iii a geometric factor that accounts for the overlap of deflagration wavelets from adjacent burn centers. These effects can be combined and the burn model defined by specifying the reaction progress variable λ = g(s as a function of a dimensionless reaction length s(t = rbc/ℓbc, rather than by specifying an explicit burn rate. The length scale ℓbc(Ps = [Nbc(Ps]−1/3 is the average distance between burn centers, where Nbc is the number density of burn centers activated by the lead shock. The reaction length rbc(t = ∫t0 D(P(t′dt′ is the distance the burn front propagates from a single burn center, where D(P is the deflagration speed as a function of the local pressure and t is the time since the shock arrival. A key implementation issue is how to determine the lead shock strength in conjunction with a shock capturing scheme. We have developed a robust algorithm for this purpose based on the Hugoniot jump condition for the energy. The algorithm utilizes the time dependence of density, pressure and energy within each cell. The method is independent of the numerical dissipation used for shock capturing. It is local and can be used in one or more space dimensions. The burn model has a small number of parameters which can be calibrated to fit velocity gauge data from shock initiation experiments.

  17. DOSE DEPENDENT EFFECTS OF SILVER NANOPARTICLES ON REPRODUCTION AND DEVELOPMENT OF DIFFERENT BIOLOGICAL MODELS

    Directory of Open Access Journals (Sweden)

    Carla Falugi

    2012-07-01

    Full Text Available The aim of this study was to investigate the possible impact of silver nanoparticles (Ag-NPs on reproduction and development of different model organisms, such as sea urchins, barnacles, brine shrimps and zebrafish. In vivo toxicological tests were performed; the biological models were exposed to serial dilutions of commercial Ag-NPs. Our findings revealed that: i all tests were suitable to verify the impact of Ag-NPs on models in term of exposure; ii all tests can provide an idea of the role of NPs on environmental health; iii an integrated interdisciplinary approach, using several model organisms, is recommended in order to have an overview of the effects of NPs on water environment.

  18. Stochastic modeling of thermal fatigue crack growth

    CERN Document Server

    Radu, Vasile

    2015-01-01

    The book describes a systematic stochastic modeling approach for assessing thermal-fatigue crack-growth in mixing tees, based on the power spectral density of temperature fluctuation at the inner pipe surface. It shows the development of a frequency-temperature response function in the framework of single-input, single-output (SISO) methodology from random noise/signal theory under sinusoidal input. The frequency response of stress intensity factor (SIF) is obtained by a polynomial fitting procedure of thermal stress profiles at various instants of time. The method, which takes into account the variability of material properties, and has been implemented in a real-world application, estimates the probabilities of failure by considering a limit state function and Monte Carlo analysis, which are based on the proposed stochastic model. Written in a comprehensive and accessible style, this book presents a new and effective method for assessing thermal fatigue crack, and it is intended as a concise and practice-or...

  19. Characterization of Growth and Reproduction Performance, Transgene Integration, Expression, and Transmission Patterns in Transgenic Pigs Produced by piggyBac Transposition-Mediated Gene Transfer.

    Science.gov (United States)

    Zeng, Fang; Li, Zicong; Cai, Gengyuan; Gao, Wenchao; Jiang, Gelong; Liu, Dewu; Urschitz, Johann; Moisyadi, Stefan; Wu, Zhenfang

    2016-10-01

    Previously we successfully produced a group of EGFP-expressing founder transgenic pigs by a newly developed efficient and simple pig transgenesis method based on cytoplasmic injection of piggyBac plasmids. In this study, we investigated the growth and reproduction performance and characterized the transgene insertion, transmission, and expression patterns in transgenic pigs generated by piggyBac transposition. Results showed that transgene has no injurious effect on the growth and reproduction of transgenic pigs. Multiple copies of monogenic EGFP transgene were inserted at noncoding sequences of host genome, and passed from founder transgenic pigs to their transgenic offspring in segregation or linkage manner. The EGFP transgene was ubiquitously expressed in transgenic pigs, and its expression intensity was associated with transgene copy number but not related to its promoter DNA methylation level. To the best of our knowledge, this is first study that fully described the growth and reproduction performance, transgene insertion, expression, and transmission profiles in transgenic pigs produced by piggyBac system. It not only demonstrates that piggyBac transposition-mediated gene transfer is an effective and favorable approach for pig transgenesis, but also provides scientific information for understanding the transgene insertion, expression and transmission patterns in transgenic animals produced by piggyBac transposition.

  20. Testing linear growth rate formulas of non-scale endogenous growth models

    NARCIS (Netherlands)

    Ziesemer, Thomas

    2017-01-01

    Endogenous growth theory has produced formulas for steady-state growth rates of income per capita which are linear in the growth rate of the population. Depending on the details of the models, slopes and intercepts are positive, zero or negative. Empirical tests have taken over the assumption of

  1. Microscopic kinetic model for polymer crystal growth

    Science.gov (United States)

    Hu, Wenbing

    2011-03-01

    Linear crystal growth rates characterize the net result of competition between growth and melting at the liquid-solid interfaces. The rate equation for polymer crystal growth can be derived with a barrier term for crystal growth and with a driving force term of excess lamellar thickness, provided that growth and melting share the same rate-determining steps at the growth front. Such an ansatz can be verified by the kinetic symmetry between growth and melting around the melting point of lamellar crystals, as made in our recent dynamic Monte Carlo simulations. The profile of the growth/melting front appears as wedge-shaped, with the free energy barrier for intramolecular secondary crystal nucleation at its top, and with the driving force gained via instant thickening at its bottom. Such a scenario explains unique phenomena on polymer crystal growth, such as chain folding, regime transitions, molecular segregation of polydisperse polymers, self-poisoning with integer-number chain-folding of short chains, and colligative growth rates of binary mixtures of two chain lengths. Financial support from NNSFC No. 20825415 and NBRPC No. 2011CB606100 is acknowledged.

  2. Modelling the dynamics of growth, development and lipid storage in the marine copepodCalanus finmarchicus.

    Science.gov (United States)

    Jager, Tjalling; Salaberria, Iurgi; Altin, Dag; Nordtug, Trond; Hansen, Bjørn Henrik

    2017-01-01

    Mechanistic models are essential tools for interpreting and predicting the consequences of a changing environment and stressors such as pollution on the life histories of marine organisms. Here, we apply the simple and generic energy-budget model DEBkiss to the life history of the marine copepod Calanus finmarchicus . Model modifications were needed to accommodate the copepod life cycle, which deviates in several respects from most other animals (e.g., a sudden stop of growth after the final moult). We identified an acceleration of growth in the early copepodite stages, which could be linked to an increase in the specific feeding rate of the animals. Lipid storage, an essential element of C. finmarchicus biology, was successfully captured with the reproduction buffer of the DEBkiss model. The resulting model was fitted to a detailed data set from the literature and was able to explain growth, development and lipid storage from egg to adult, at different temperatures and food availabilities, within a single consistent framework. The parameterised model could subsequently be used to elucidate the energetic constraints on gonad maturation and reproduction. Interestingly, the overhead costs for egg production seem to be substantially higher than the default value applied in DEB-based studies. The current model provides a solid basis for applications in stress ecology, although our model analysis also identified several knowledge gaps. Specifically, further research is needed to cover the dynamics of diapause and gonad maturation, to explain the dependence of maximum body size on food and temperature, and to verify the predicted high costs for maturity maintenance.

  3. On the Age, Growth and Reproduction of the Barbel, Barbus plebejus escherichi (Steindachner, 1897) in the Oltu Stream of Çoruh River (Artvin-Turkey)

    OpenAIRE

    YILDIRIM, Ayhan

    2014-01-01

    In this study, the age, growth and reproduction properties of 627 barbels, Barbus plebejus escherichi (Steindachner, 1897), from Oltu Stream in the Çoruh River Basin were investigated during a period from August 1994 to July 1996. The age of this species ranged between age groups 1 and 10, the second age group being dominant. Individuals were composed of 64.59% males and 35.41% females. von Bertalanffy growth parameters and length-weight relationships were Lt=29.35x(1-e-0.139(t+1.640)), W...

  4. A literature review on growth models and strategies: The missing link in entrepreneurial growth

    Directory of Open Access Journals (Sweden)

    Syed Fida Hussain Shah

    2013-08-01

    Full Text Available This study focuses on the importance of growth models, growth strategies, role of knowledge management system in the formulation of effective strategy for the enterprises following growth. Choice of an appropriate growth strategy is at the heart of any successful entrepreneurial venture. Selection of a strategy may be effective for one entrepreneur while it is not for other. Choice of Growth Strategy depends on various different factors, organisational context and environment which may vary from enterprise to enterprise. Resource based view is very important consideration for the entrepreneurs on the path of growth. Evaluation of all kind of resources helps them to grow their enterprises successfully. Selection of an appropriate growth strategy allows the entrepreneurs in overcoming growth challenges and avoiding the growth reversals and setbacks.

  5. Intergenerational conflicts may help explain parental absence effects on reproductive timing: a model of age at first birth in humans

    Directory of Open Access Journals (Sweden)

    Cristina Moya

    2014-08-01

    Full Text Available Background. Parental absences in childhood are often associated with accelerated reproductive maturity in humans. These results are counterintuitive for evolutionary social scientists because reductions in parental investment should be detrimental for offspring, but earlier reproduction is generally associated with higher fitness. In this paper we discuss a neglected hypothesis that early reproduction is often associated with parental absence because it decreases the average relatedness of a developing child to her future siblings. Family members often help each other reproduce, meaning that parents and offspring may find themselves in competition over reproductive opportunities. In these intergenerational negotiations offspring will have less incentive to help the remaining parent rear future half-siblings relative to beginning reproduction themselves.Method. We illustrate this “intergenerational conflict hypothesis” with a formal game-theoretic model.Results. We show that when resources constrain reproductive opportunities within the family, parents will generally win reproductive conflicts with their offspring, i.e., they will produce more children of their own and therefore delay existing offsprings’ reproduction. This is due to the asymmetric relatedness between grandparents and grandchildren (r = .25, compared to siblings (r = 0.5, resulting in greater incentives for older siblings to help rear younger siblings than for grandparents to help rear grandchildren. However, if a parent loses or replaces their partner, the conflict between the parent and offspring becomes symmetric since half siblings are as related to one another as grandparents are to grandchildren. This means that the offspring stand to gain more from earlier reproduction when their remaining parent would produce half, rather than full, siblings. We further show that if parents senesce in a way that decreases the quality of their infant relative to their offspring

  6. Bayesian modeling of bacterial growth for multiple populations

    OpenAIRE

    Palacios, Ana Paula; Marín, J. Miguel; Quinto, Emiliano J.; Wiper, Michael P.

    2014-01-01

    Bacterial growth models are commonly used for the prediction of microbial safety and the shelf life of perishable foods. Growth is affected by several environmental factors such as temperature, acidity level and salt concentration. In this study, we develop two models to describe bacterial growth for multiple populations under both equal and different environmental conditions. Firstly, a semi-parametric model based on the Gompertz equation is proposed. Assuming that the parameters of the Gomp...

  7. Bayesian modelling of bacterial growth for multiple populations

    OpenAIRE

    Palacios, Ana Paula; Marín Díazaraque, Juan Miguel; Quinto, Emiliano; Wiper, Michael Peter

    2012-01-01

    Bacterial growth models are commonly used for the prediction of microbial safety and the shelf life of perishable foods. Growth is affected by several environmental factors such as temperature, acidity level and salt concentration. In this study, we develop two models to describe bacterial growth for multiple populations under both equal and different environmental conditions. Firstly, a semi-parametric model based on the Gompertz equation is proposed. Assuming that the parameters of the Gomp...

  8. Parker's sneak-guard model revisited: why do reproductively parasitic males heavily invest in testes?

    Science.gov (United States)

    Ota, Kazutaka; Kohda, Masanori; Hori, Michio; Sato, Tetsu

    2011-10-01

    Alternative reproductive tactics are widespread in males and may cause intraspecific differences in testes investment. Parker's sneak-guard model predicts that sneaker males, who mate under sperm competition risk, invest in testes relatively more than bourgeois conspecifics that have lower risk. Given that sneakers are much smaller than bourgeois males, sneakers may increase testes investment to overcome their limited sperm productivity because of their small body sizes. In this study, we examined the mechanism that mediates differential testes investment across tactics in the Lake Tanganyika cichlid fish Lamprologus callipterus. In the Rumonge population of Burundi, bourgeois males are small compared with those in other populations and have a body size close to sneaky dwarf males. Therefore, if differences in relative testis investment depend on sperm competition, the rank order of relative testis investment should be dwarf males > bourgeois males in Rumonge = bourgeois males in the other populations. If differences in relative testis investment depend on body size, the rank order of relative testes investment should be dwarf males > bourgeois males in Rumonge > bourgeois males in the other populations. Comparisons of relative testis investment among the three male groups supported the role of sperm competition, as predicted by the sneak-guard model. Nevertheless, the effects of absolute body size on testes investment should be considered to understand the mechanisms underlying intraspecific variation in testes investment caused by alternative reproductive tactics.

  9. A Reproductive Threat-Based Model of Evolved Sex Differences in Jealousy

    Directory of Open Access Journals (Sweden)

    Brad J. Sagarin

    2012-07-01

    Full Text Available Although heterosexual women and men consistently demonstrate sex differences in jealousy, these differences disappear among lesbians and gay men as well as among heterosexual women and men contemplating same-sex infidelities (infidelities in which the partner and rival are the same sex. Synthesizing these past findings, the present paper offers a reproductive threat-based model of evolved sex differences in jealousy that predicts that the sexes will differ only when the jealous perceivers' reproductive outcomes are differentially at risk. This model is supported by data from a web-based study in which lesbians, gay men, bisexual women and men, and heterosexual women and men responded to a hypothetical infidelity scenario with the sex of the rival randomly determined. After reading the scenario, participants indicated which type of infidelity (sexual versus emotional would cause greater distress. Consistent with predictions, heterosexual women and men showed a sex difference when contemplating opposite-sex infidelities but not when contemplating same-sex infidelities, whereas lesbians and gay men showed no sex difference regardless of whether the infidelity was opposite-sex or same-sex.

  10. A reproductive threat-based model of evolved sex differences in jealousy.

    Science.gov (United States)

    Sagarin, Brad J; Becker, D Vaughn; Guadagno, Rosanna E; Wilkinson, Wayne W; Nicastle, Lionel D

    2012-08-10

    Although heterosexual women and men consistently demonstrate sex differences in jealousy, these differences disappear among lesbians and gay men as well as among heterosexual women and men contemplating same-sex infidelities (infidelities in which the partner and rival are the same sex). Synthesizing these past findings, the present paper offers a reproductive threat-based model of evolved sex differences in jealousy that predicts that the sexes will differ only when the jealous perceivers' reproductive outcomes are differentially at risk. This model is supported by data from a web-based study in which lesbians, gay men, bisexual women and men, and heterosexual women and men responded to a hypothetical infidelity scenario with the sex of the rival randomly determined. After reading the scenario, participants indicated which type of infidelity (sexual versus emotional) would cause greater distress. Consistent with predictions, heterosexual women and men showed a sex difference when contemplating opposite-sex infidelities but not when contemplating same-sex infidelities, whereas lesbians and gay men showed no sex difference regardless of whether the infidelity was opposite-sex or same-sex.

  11. Bacterial Reproduction and Growth

    NARCIS (Netherlands)

    Scheffers, DJ

    2013-01-01

    Bacteria growing in a suitable medium increase in number by having each cell increase in size, and then each cell divides to produce two daughter cells. The increase in cell number in a culture is, therefore, a result of the activity of the cell during the division cycle, between the period of birth

  12. Naloxone affects reproductive system in a rat model with polycystic features

    Directory of Open Access Journals (Sweden)

    Manizheh Karami

    2015-03-01

    Conclusion: Aspect of rat reproductive system may be linked with the cystic characteristic of ovary. This study involves opioid receptors in the naloxone efficacy on reproductive agents of rat with polycystic aspect.

  13. Modeling the growth rates of tetragonal lysozyme crystals

    Science.gov (United States)

    Li, Meirong; Nadarajah, Arunan; Pusey, Marc L.

    1995-11-01

    Although the faceted growth of tetragonal lysozyme crystals is known to occur by 2D nucleation and dislocation-led growth, the measured growth rates do not follow model predictions based on these mechanisms. One possible reason for this deviation is that these models ignore the highly aggregated state of lysozyme in supersaturated solutions. In this study a growth mechanism for tetragonal lysozyme crystals involving aggregation reactions leading to the formation of the growth unit, mass transport of the growth unit to the crystal interface and faceted crystal growth by growth unit addition, is proposed. The distribution of aggregates in lysozyme nutrient solutions were determined from the equilibrium aggregation reactions and comparisons were made with growth rates calculated from the model based on the proposed mechanism and the measured growth rate data. The results indicated than an octamer corresponding to the tetragonal crystal unit cell was the most likely growth unit for the process. Remarkably good fits were obtained with this model to the measured growth rate data for three sets of pH and salt concentrations, suggesting the validity of the proposed mechanism. The values of the kinetic coefficient for the step velocity was in the range for small molecule crystal growth and the heats of reaction compared well with that obtained from lysozyme solubility data. The results presented here suggest that the inorganic and protein crystal growth processes are quite similar in many ways. Lysozyme crystal growth differs primarily due to growth by an aggregate growth unit and in the effect of nutrient solution conditions on the protein aggregation process.

  14. An autocatalytic kinetic model for describing microbial growth during fermentation.

    Science.gov (United States)

    Ibarz, Albert; Augusto, Pedro E D

    2015-01-01

    The mathematical modelling of the behaviour of microbial growth is widely desired in order to control, predict and design food and bioproduct processing, stability and safety. This work develops and proposes a new semi-empirical mathematical model, based on an autocatalytic kinetic, to describe the microbial growth through its biomass concentration. The proposed model was successfully validated using 15 microbial growth patterns, covering the three most important types of microorganisms in food and biotechnological processing (bacteria, yeasts and moulds). Its main advantages and limitations are discussed, as well as the interpretation of its parameters. It is shown that the new model can be used to describe the behaviour of microbial growth.

  15. Models of Economic Growth and Development in the Context of ...

    African Journals Online (AJOL)

    The Way Forward for Africa. Lansana Keita* ... to such progress. Key Words: economic growth, economic development, human capital, growth models. Résumé. La littérature économique depuis l'avènement de l'économie moderne a été ..... between the economy's growth rate according to investment and the propensity to ...

  16. Animal models of physiologic markers of male reproduction: genetically defined infertile mice

    Energy Technology Data Exchange (ETDEWEB)

    Chubb, C.

    1987-10-01

    The present report focuses on novel animal models of male infertility: genetically defined mice bearing single-gene mutations that induce infertility. The primary goal of the investigations was to identify the reproductive defects in these mutant mice. The phenotypic effects of the gene mutations were deciphered by comparing the mutant mice to their normal siblings. Initially testicular steroidogenesis and spermatogenesis were investigated. The physiologic markers for testicular steroidogenesis were steroid secretion by testes perifused in vitro, seminal vesicle weight, and Leydig cell histology. Spermatogenesis was evaluated by the enumeration of homogenization-resistant sperm/spermatids in testes and by morphometric analyses of germ cells in the seminiferous epithelium. If testicular function appeared normal, the authors investigated the sexual behavior of the mice. The parameters of male sexual behavior that were quantified included mount patency, mount frequency, intromission latency, thrusts per intromission, ejaculation latency, and ejaculation duration. Females of pairs breeding under normal circumstances were monitored for the presence of vaginal plugs and pregnancies. The patency of the ejaculatory process was determined by quantifying sperm in the female reproductive tract after sexual behavior tests. Sperm function was studied by quantitatively determining sperm motility during videomicroscopic observation. Also, the ability of epididymal sperm to function within the uterine environment was analyzed by determining sperm capacity to initiate pregnancy after artificial insemination. Together, the experimental results permitted the grouping of the gene mutations into three general categories. They propose that the same biological markers used in the reported studies can be implemented in the assessment of the impact that environmental toxins may have on male reproduction.

  17. Parthenogenetic reproduction of Diaphanosoma celebensis (Crustacea: Cladocera): influence of salinity on feeding, survival, growth and neonate production

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Shrivastava; Mahambre, G.G.; Goswami, S.C.; Madhupratap

    Effect of salinity on the feeding rate and parthenogenetic reproduction of asexual females of the cladoceran Diaphanosoma celebensis Stingelin was studied. Short-term (10 h) grazing experiments were conducted using Isochrysis galbana as feed at 5...

  18. Growth Kinetics and Modeling of Direct Oxynitride Growth with NO-O2 Gas Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Everist, Sarah; Nelson, Jerry; Sharangpani, Rahul; Smith, Paul Martin; Tay, Sing-Pin; Thakur, Randhir

    1999-05-03

    We have modeled growth kinetics of oxynitrides grown in NO-O2 gas mixtures from first principles using modified Deal-Grove equations. Retardation of oxygen diffusion through the nitrided dielectric was assumed to be the dominant growth-limiting step. The model was validated against experimentally obtained curves with good agreement. Excellent uniformity, which exceeded expected walues, was observed.

  19. Modeling Urban Spatial Growth in Mountainous Regions of Western China

    Directory of Open Access Journals (Sweden)

    Guoping Huang

    2017-08-01

    Full Text Available The scale and speed of urbanization in the mountainous regions of western China have received little attention from researchers. These cities are facing rapid population growth and severe environmental degradation. This study analyzed historical urban growth trends in this mountainous region to better understand the interaction between the spatial growth pattern and the mountainous topography. Three major factors—slope, accessibility, and land use type—were studied in light of their relationships with urban spatial growth. With the analysis of historical data as the basis, a conceptual urban spatial growth model was devised. In this model, slope, accessibility, and land use type together create resistance to urban growth, while accessibility controls the sequence of urban development. The model was tested and evaluated using historical data. It serves as a potential tool for planners to envision and assess future urban growth scenarios and their potential environmental impacts to make informed decisions.

  20. Transmission of a heterologous clade C Symbiodinium in a model anemone infection system via asexual reproduction

    Directory of Open Access Journals (Sweden)

    Wan-Nan U. Chen

    2016-08-01

    Full Text Available Anemones of genus Exaiptasia are used as model organisms for the study of cnidarian-dinoflagellate (genus Symbiodinium endosymbiosis. However, while most reef-building corals harbor Symbiodinium of clade C, Exaiptasia spp. anemones mainly harbor clade B Symbiodinium (ITS2 type B1 populations. In this study, we reveal for the first time that bleached Exaiptasia pallida anemones can establish a symbiotic relationship with a clade C Symbiodinium (ITS2 type C1. We further found that anemones can transmit the exogenously supplied clade C Symbiodinium cells to their offspring by asexual reproduction (pedal laceration. In order to corroborate the establishment of stable symbiosis, we used microscopic techniques and genetic analyses to examine several generations of anemones, and the results of these endeavors confirmed the sustainability of the system. These findings provide a framework for understanding the differences in infection dynamics between homologous and heterologous dinoflagellate types using a model anemone infection system.

  1. Differential model of macroeconomic growth with endogenic cyclicity

    Directory of Open Access Journals (Sweden)

    Mikhail I. Geraskin

    2017-09-01

    Full Text Available Objective to elaborate a mathematical model of economic growth taking into account the cyclical nature of macroeconomic dynamics with the model parameters based on the Russian economy statistics. Methods economic and mathematical modeling system analysis regression factor analysis econometric time series analysis. Results the article states that under unstable economic growth in Russia forecasting of strategic prospects of the Russian economy is one of the topical directions of scientific studies. Furthermore construction of predictive models should be based on multiple factors taking into account such basic concepts as the neoKeynesian HarrodDomar model Ramsey ndash Cass ndash Koopmans model S. V. Dubovskiyrsquos concept as well as the neoclassical growth model by R. Solow. They served as the basis for developing a multifactor differential economic growth model which is a modification of the neoclassical growth model by R. Solow taking into account the laborsaving and capitalsaving forms of scientifictechnical progress and the Keynesian concept of investment. The model parameters are determined based on the dynamics of actual GDP employment fixed assets and investments in fixed assets for 19652016 in Russia on the basis of official statistics. The generalized model showed the presence of longwave fluctuations that are not detected during the individual periods modeling. The cyclical nature of macroeconomic dynamics with a period of 54 years was found which corresponds to the parameters of long waves by N. D. Kondratiev. Basing on the model the macroeconomic growth forecast was generated which shows that after 2020 the increase of scientifictechnical progress will be negative. Scientific novelty a model is proposed of the scientifictechnical progress indicator showing the growth rate of the capital productivity ratio to the saving rate a differential model of macroeconomic growth is obtained which endogenously takes cyclicity into account

  2. Inductions of reproduction and population growth in the generalist predator Cyrtorhinus lividipennis (Hemiptera: Miridae) exposed to sub-lethal concentrations of insecticides.

    Science.gov (United States)

    Lu, Weiwei; Xu, Qiujing; Zhu, Jun; Liu, Chen; Ge, Linquan; Yang, Guoqing; Liu, Fang

    2017-08-01

    The miridbug, Cyrtorhinus lividipennis, is a significant predacious enemy of rice planthoppers. The effects of sub-lethal concentrations of triazophos, deltamethrin and imidacloprid on fecundity, egg hatchability, expression levels of genes associated with reproduction, and population growth in C. lividipennis were investigated. The fecundities for three pair combinations (♀ c × ♂ t , ♀ t × ♂ c and ♀ t × ♂ t ) treated with sub-lethal concentrations of the insecticides triazophos, deltamethrin and imidacloprid (LC 10 and LC 20 ) showed a significant increase compared to the untreated pairs (♀ c × ♂ c ). However, sub-lethal concentration treatments did not affect the egg hatchability. The ClVg expression levels of female adults exposed to triazophos, deltamethrin and imidacloprid (LC 20 ) increased by 52.6, 48.9 and 91.2%, respectively. The ClSPATA13 expression level of adult males exposed to triazophos, deltamethrim and imidacloprid (LC 20 ) increased by 80.7, 41.3 and 48.3%, respectively. Furthermore, sub-lethal concentrations of insecticides (LC 20 ) caused increased population numbers in C. lividipennis. Sub-lethal concentrations of triazophos, deltamethrin and imidacloprid stimulated reproduction and enhanced population growth of C. lividipennis. The reproductive stimulation might result from the up-regulation of ClVg or ClSPATA13. These findings may be useful in mediating populations of planthoppers. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  3. Nonsteroidal Anti-inflammatory Drugs (NSAIDS) Inhibit the Growth and Reproduction of Chaetomium globosum and Other Fungi Associated with Water-Damaged Buildings.

    Science.gov (United States)

    Dalmont, Kelsey; Biles, Charles L; Konsure, Heather; Dahal, Sujita; Rowsey, Tyler; Broge, Matthew; Poudyal, Shubhra; Gurung, Tara; Shrestha, Sabina; Biles, Caleb L; Cluck, Terry; Howard, Alisha

    2017-12-01

    Indoor mold due to water damage causes serious human respiratory disorders, and the remediation to homes, schools, and businesses is a major expense. Prevention of mold infestation of building materials would reduce health problems and building remediation costs. Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit yeasts and a limited number of filamentous fungi. The purpose of this research was to determine the possible inhibitory activity of nonsteroidal anti-inflammatory drugs (NSAIDs) on germination, fungal growth, and reproduction of Chaetomium globosum and other important filamentous fungi that occur in water-damaged buildings. Several NSAIDs were found to inhibit C. globosum germination, growth, and reproduction. The most effective NSAIDs inhibiting C. globosum were ibuprofen, diflunisal, and diclofenac. Fusarium oxysporum, Fusarium solani, Aspergillus niger, and Stachybotrys atra were also tested on the various media with similar results obtained. However, F. oxysporum and A. niger exhibited a higher level of resistance to aspirin and NaSAL when compared to the C. globosum isolates. The inhibition exhibited by NSAIDs was variable depending on growth media and stage of fungal development. These compounds have a great potential of inhibiting fungal growth on building materials such as gypsum board. Formulations of sprays or building materials with NSAID-like chemical treatments may hold promise in reducing mold in homes and buildings.

  4. The effect of DNA repair defects on reproductive performance in nucleotide excision repair (NER) mouse models: an epidemiological approach

    NARCIS (Netherlands)

    Tsai, P.S.; Nielen, M.; Horst, G.T.J. van der; Colenbrander, B.; Heesterbeek, J.A.P.; Fentener van Vlissingen, J.M.

    2005-01-01

    In this study, we used an epidemiological approach to analyze an animal database of DNA repair deficient mice on reproductive performance in five Nucleotide Excision Repair (NER) mutant mouse models on a C57BL/6 genetic background, namely CSA, CSB, XPA, XPC [models for the human DNA repair disorders

  5. Modeling the effects of ozone on soybean growth and yield.

    Science.gov (United States)

    Kobayashi, K; Miller, J E; Flagler, R B; Heck, W W

    1990-01-01

    A simple mechanistic model was developed based on an existing growth model in order to address the mechanisms of the effects of ozone on growth and yield of soybean [Glycine max. (L.) Merr. 'Davis'] and interacting effects of other environmental stresses. The model simulates daily growth of soybean plants using environmental data including shortwave radiation, temperature, precipitation, irrigation and ozone concentration. Leaf growth, dry matter accumulation, water budget, nitrogen input and seed growth linked to senescence and abscission of leaves are described in the model. The effects of ozone are modeled as reduced photosynthate production and accelerated senescence. The model was applied to the open-top chamber experiments in which soybean plants were exposed to ozone under two levels of soil moisture regimes. After calibrating the model to the growth data and seed yield, goodness-of-fit of the model was tested. The model fitted well for top dry weight in the vegetative growth phase and also at maturity. The effect of ozone on seen yield was also described satisfactorily by the model. The simulation showed apparent interaction between the effect of ozone and soil moisture stress on the seed yield. The model revealed that further work is needed concerning the effect of ozone on the senescence process and the consequences of alteration of canopy microclimate by the open-top chambers.

  6. Validation of a predictive model for the growth of chalk yeasts on bread.

    Science.gov (United States)

    Burgain, Anaïs; Bensoussan, Maurice; Dantigny, Philippe

    2015-07-02

    The present study focused on the effects of temperature, T, and water activity, aw, on the growth of Hyphopichia burtonii, Pichia anomala, and Saccharomycopsis fibuligera on Sabouraud Agar Medium. Cardinal values were estimated by means of cardinal models with inflection. All the yeasts were xerophilic, and they exhibited growth at 0.85 aw. The combined effects of T, aw, and pH on the growth of these species were described by the gamma-concept and validated on bread in the range of 15-25 °C, 0.91-0.97 aw, and pH 4.6-6.8. The optimum growth rates on bread were 2.88, 0.259, and 1.06 mm/day for H. burtonii, P. anomala, and S. fibuligera, respectively. The optimal growth rate of S. fibuligera on bread was about 2 fold that obtained on Sabouraud. Due to reproduction by budding, P. anomala exhibited low growth on Sabouraud and bread. However, this species is of major concern in the baker's industry because of the production of ethyl acetate in bread. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Is it photosensitization or photodegradation when UV-B irradiation is combined with BDE-47? Evidence from the growth and reproduction changes of rotifer Brachionus plicatilis.

    Science.gov (United States)

    Liu, Chunchen; Tang, Xuexi; Zhou, Bin; Jiang, Yongshun; Lv, Mengchen; Zang, Yu; Wang, You

    2018-07-01

    Ecotoxicological methods were applied in the present study, and the marine rotifer Brachionus plicatilis was used as the toxic endpoint to depict what occurred when 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) was combined with solar ultraviolet-B radiation (UV-B). B. plicatilis was exposed to three different combination methods of BDE-47 and UV-B at an equal toxicity ratio, including normal rotifer co-cultured with UV-B-irradiated BDE-47 (known as Method I), UV-B-irradiated rotifer co-cultured with BDE-47 exposure (known as Method II) and normal rotifer co-cultured with the simultaneous addition of BDE-47 and UV-B irradiation (known as Method III). Acute and chronic experiments were preformed to determine the toxicity differentiation according to the growth and reproduction changes in the rotifer. Twenty-four-hour acute experiments showed that the modes of three combined methods changed from antagonism to additive, to synergistic with the concentration/dose increment, and the contribution rates of Method I and Method II to Method III were calculated by approximately 40.4% and 59.6%, respectively. Chronic exposure to either the single stressor or the combination of stressors inhibited the growth and reproduction of the rotifer, demonstrating the inhibition of the population growth rate and the decrease in the larvae production. Three combined groups presented more serious damages compared to groups with single stress exposure, and the ascending sequence of toxicity was Method IB was mainly due to photosensitization and photodegradation, and the photosensitization might be more noxious to the growth and reproduction of the rotifer. Copyright © 2018. Published by Elsevier B.V.

  8. Stochastic growth logistic model with aftereffect for batch fermentation process

    International Nuclear Information System (INIS)

    Rosli, Norhayati; Ayoubi, Tawfiqullah; Bahar, Arifah; Rahman, Haliza Abdul; Salleh, Madihah Md

    2014-01-01

    In this paper, the stochastic growth logistic model with aftereffect for the cell growth of C. acetobutylicum P262 and Luedeking-Piret equations for solvent production in batch fermentation system is introduced. The parameters values of the mathematical models are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic models numerically. The effciency of mathematical models is measured by comparing the simulated result and the experimental data of the microbial growth and solvent production in batch system. Low values of Root Mean-Square Error (RMSE) of stochastic models with aftereffect indicate good fits

  9. Stochastic growth logistic model with aftereffect for batch fermentation process

    Energy Technology Data Exchange (ETDEWEB)

    Rosli, Norhayati; Ayoubi, Tawfiqullah [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia); Bahar, Arifah; Rahman, Haliza Abdul [Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Salleh, Madihah Md [Department of Biotechnology Industry, Faculty of Biosciences and Bioengineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

    2014-06-19

    In this paper, the stochastic growth logistic model with aftereffect for the cell growth of C. acetobutylicum P262 and Luedeking-Piret equations for solvent production in batch fermentation system is introduced. The parameters values of the mathematical models are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic models numerically. The effciency of mathematical models is measured by comparing the simulated result and the experimental data of the microbial growth and solvent production in batch system. Low values of Root Mean-Square Error (RMSE) of stochastic models with aftereffect indicate good fits.

  10. Constrained minimization problems for the reproduction number in meta-population models.

    Science.gov (United States)

    Poghotanyan, Gayane; Feng, Zhilan; Glasser, John W; Hill, Andrew N

    2018-02-14

    The basic reproduction number ([Formula: see text]) can be considerably higher in an SIR model with heterogeneous mixing compared to that from a corresponding model with homogeneous mixing. For example, in the case of measles, mumps and rubella in San Diego, CA, Glasser et al. (Lancet Infect Dis 16(5):599-605, 2016. https://doi.org/10.1016/S1473-3099(16)00004-9 ), reported an increase of 70% in [Formula: see text] when heterogeneity was accounted for. Meta-population models with simple heterogeneous mixing functions, e.g., proportionate mixing, have been employed to identify optimal vaccination strategies using an approach based on the gradient of the effective reproduction number ([Formula: see text]), which consists of partial derivatives of [Formula: see text] with respect to the proportions immune [Formula: see text] in sub-groups i (Feng et al. in J Theor Biol 386:177-187, 2015.  https://doi.org/10.1016/j.jtbi.2015.09.006 ; Math Biosci 287:93-104, 2017.  https://doi.org/10.1016/j.mbs.2016.09.013 ). These papers consider cases in which an optimal vaccination strategy exists. However, in general, the optimal solution identified using the gradient may not be feasible for some parameter values (i.e., vaccination coverages outside the unit interval). In this paper, we derive the analytic conditions under which the optimal solution is feasible. Explicit expressions for the optimal solutions in the case of [Formula: see text] sub-populations are obtained, and the bounds for optimal solutions are derived for [Formula: see text] sub-populations. This is done for general mixing functions and examples of proportionate and preferential mixing are presented. Of special significance is the result that for general mixing schemes, both [Formula: see text] and [Formula: see text] are bounded below and above by their corresponding expressions when mixing is proportionate and isolated, respectively.

  11. Modelling of the growth of a methanotrophic biofilm

    DEFF Research Database (Denmark)

    Arcangeli, J.-P.; Arvin, E.

    1997-01-01

    A model describing the growth of a methanotrophic biofilm is presented. This model involves simultaneous growth of methanotrophs, heterotrophs and nitrifiers. Heterotrophic biomass grows on soluble polymers which arise from the hydrolysis of dead biomass entrapped in the biofilm. Nitrifiers develop...

  12. Modelling growth of five different colour types of mink

    African Journals Online (AJOL)

    p2492989

    first introduced in China at the beginning of the 20th century for fur farming. Interest in mink is excited by its economic .... of inflection and is mainly used to describe the postnatal growth of an individual. Table 1 Functions considered in this study for modelling the growth curve of the mink. Model. Equation. No of parameters.

  13. A generic view of classic microbial growth models.

    NARCIS (Netherlands)

    van den Berg, H.A.

    1998-01-01

    General theoretical aspects are reviewed of models for microbial growth and endogenous metabolism. The focus is on a generic cell model with two components. Growth is represented as the increase of one of these components (the structural scaffolding or 'frame'). A novel feature of the present

  14. Modelling of transport phenomena and defects in crystal growth ...

    Indian Academy of Sciences (India)

    A brief review of single crystal growth techniques and the associated problems is presented. Emphasis is placed on models for various transport and defect phenomena involoved in the growth process with the ultimate aim of integrating them into a comprehensive numerical model. The sources of dislocation nucleation in ...

  15. Spatially explicit models, generalized reproduction numbers and the prediction of patterns of waterborne disease

    Science.gov (United States)

    Rinaldo, A.; Gatto, M.; Mari, L.; Casagrandi, R.; Righetto, L.; Bertuzzo, E.; Rodriguez-Iturbe, I.

    2012-12-01

    still lacking. Here, we show that the requirement that all the local reproduction numbers R0 be larger than unity is neither necessary nor sufficient for outbreaks to occur when local settlements are connected by networks of primary and secondary infection mechanisms. To determine onset conditions, we derive general analytical expressions for a reproduction matrix G0 explicitly accounting for spatial distributions of human settlements and pathogen transmission via hydrological and human mobility networks. At disease onset, a generalized reproduction number Λ0 (the dominant eigenvalue of G0) must be larger than unity. We also show that geographical outbreak patterns in complex environments are linked to the dominant eigenvector and to spectral properties of G0. Tests against data and computations for the 2010 Haiti and 2000 KwaZulu-Natal cholera outbreaks, as well as against computations for metapopulation networks, demonstrate that eigenvectors of G0 provide a synthetic and effective tool for predicting the disease course in space and time. Networked connectivity models, describing the interplay between hydrology, epidemiology and social behavior sustaining human mobility, thus prove to be key tools for emergency management of waterborne infections.

  16. Growth rate in the dynamical dark energy models.

    Science.gov (United States)

    Avsajanishvili, Olga; Arkhipova, Natalia A; Samushia, Lado; Kahniashvili, Tina

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

  17. Non-rigid image registration using bone growth model

    DEFF Research Database (Denmark)

    Bro-Nielsen, Morten; Gramkow, Claus; Kreiborg, Sven

    1997-01-01

    Non-rigid registration has traditionally used physical models like elasticity and fluids. These models are very seldom valid models of the difference between the registered images. This paper presents a non-rigid registration algorithm, which uses a model of bone growth as a model of the change b...

  18. The reproduction accuracy for stereolithographic model of the thyroid gland derived from the visible human dataset.

    Science.gov (United States)

    Kapakin, Samet; Demiryurek, Deniz

    2009-07-01

    To investigate reproduction accuracy of the rapid prototyping technique by comparing 3-dimensional computer-aided design (CAD) (virtual) model with stereolithographic (solid) replica of the thyroid gland. The Visible Human Dataset was used as the input imaging data. The Surfdriver software package was applied on these images to reconstruct the thyroid gland as 3-dimensional Data Exchange File (DXF) models. These models were post-processed in Cinema 4D and 3D-Doctor software for Virtual Reality Modeling Language (VRML) and Standard Triangulation Language (STL) formats. Stereolithographic replica was manufactured in the rapid prototyping machine using STL format. This study was conducted between June 1-30, 2008 at the Department of Anatomy, Hacettepe University, Ankara, Turkey. An excellent agreement was found in comparing the maximal dimensions of the CAD model of the thyroid gland and the corresponding stereolithographic model. Visual and tactile examination of the thyroid gland model allowed correct depiction of the thyroid gland anatomy. The accuracy of the stereolithographic model was attained by comparing wih the CAD model. Dimensional analysis showed that an average difference between the measurements on the virtual and the solid model was 0.09 mm (p=0.06), ranging from 0.07-0.92 mm. Thyroid volume and surface area were calculated to be 25393.9 mm3 and 8242.8 mm2 using 3D-Doctor software, which were agreement with those obtained from Brunn's formula. Stereolithographic biomodeling is a state-of-the-art and reliable method of visualizing anatomoclinical structures and abnormalities.

  19. Modeling and testing treated tumor growth using cubic smoothing splines.

    Science.gov (United States)

    Kong, Maiying; Yan, Jun

    2011-07-01

    Human tumor xenograft models are often used in preclinical study to evaluate the therapeutic efficacy of a certain compound or a combination of certain compounds. In a typical human tumor xenograft model, human carcinoma cells are implanted to subjects such as severe combined immunodeficient (SCID) mice. Treatment with test compounds is initiated after tumor nodule has appeared, and continued for a certain time period. Tumor volumes are measured over the duration of the experiment. It is well known that untreated tumor growth may follow certain patterns, which can be described by certain mathematical models. However, the growth patterns of the treated tumors with multiple treatment episodes are quite complex, and the usage of parametric models is limited. We propose using cubic smoothing splines to describe tumor growth for each treatment group and for each subject, respectively. The proposed smoothing splines are quite flexible in modeling different growth patterns. In addition, using this procedure, we can obtain tumor growth and growth rate over time for each treatment group and for each subject, and examine whether tumor growth follows certain growth pattern. To examine the overall treatment effect and group differences, the scaled chi-squared test statistics based on the fitted group-level growth curves are proposed. A case study is provided to illustrate the application of this method, and simulations are carried out to examine the performances of the scaled chi-squared tests. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Long-term effects of antibiotics, norfloxacin, and sulfamethoxazole, in a partial life-cycle study with zebrafish (Danio rerio): effects on growth, development, and reproduction.

    Science.gov (United States)

    Yan, Zhenhua; Lu, Guanghua; Ye, Qiuxia; Liu, Jianchao

    2016-09-01

    A partial life-cycle study with zebrafish (Danio rerio) was conducted to evaluate the long-term effects of antibiotics, norfloxacin (NOR) and sulfamethoxazole (SMX). A series of bio-endpoints correlated to the growth, development, and reproduction was assessed. The results showed that the body weight and the condition factor were depressed by SMX at 200 μg/L during the growth period. Meanwhile, the activities of metabolic enzyme (ethoxyresorufin O-deethylase, EROD) and antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT) were stimulated in all cases. The consequences of parental exposure to antibiotics for the next generation were also examined. The egg production of parents were depressed by the 200 μg/L NOR and SMX alone or in combination. Similarly, decreased hatching, survival, and enhanced development abnormality of the next generation also occurred after parental exposure to SMX at the highest concentration. The heartbeat however was not altered in all cases. Furthermore, there was no significant difference in the bio-endpoints between the combined and individual treatment in most cases, with the exception of lower EROD activity and egg production in the co-treatment. The results suggest that long-term exposure to NOR and SMX at environmentally relevant concentrations, individually and in a mixture, may not significantly pose a threat to the growth, development, and reproduction of zebrafish, and an adverse effect may be expected at high concentration.

  1. Bio-effects of near-zero magnetic fields on the growth, development and reproduction of small brown planthopper, Laodelphax striatellus and brown planthopper, Nilaparvata lugens.

    Science.gov (United States)

    Wan, Gui-jun; Jiang, Shou-lin; Zhao, Zong-chao; Xu, Jing-jing; Tao, Xiao-rong; Sword, Gregory A; Gao, Yue-bo; Pan, Wei-dong; Chen, Fa-jun

    2014-09-01

    Magnetic fields markedly affect the growth and development of many species of organisms potentially due to cryptochrome and endogenous presence of magnetic materials. Sensitivity to magnetic fields can also be involved in geomagnetic orientation by some long-distance migratory insects. In this study, near-zero magnetic fields (NZMF) in relation to normal geomagnetic fields (GMF) were setup using the Hypomagnetic Field Space System (HMFs) to investigate the effects of magnetic fields on the growth, development and reproduction of two species of migratory planthopper, the small brown planthopper (abbr. SBPH), Laodelphax striatellus, and the brown planthopper (abbr. BPH), Nilaparvata lugens. Exposure of both L. striatellus and N. lugens to NZMF delayed egg and nymphal developmental durations and decreased adult weight and female fecundity. The 1st-5th instars of SBPH and BPH showed different responses to NZMF. The 4th instar was significantly affected by NZMF, especially for BPH males, in which NZMF exposure reduced the difference in development duration between females and males. Compared with GMF, the vitellogenin transcript levels of newly molted female adults and the number of eggs per female were significantly reduced in both planthopper species, indicating a negative effect on fertility under NZMF. Our findings provided experimental evidence that NZMF negatively affected the growth and development of SBPH and BPH, with particularly strong effects on reproduction. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Modeling and optimization of algae growth

    NARCIS (Netherlands)

    Thornton, Anthony Richard; Weinhart, Thomas; Bokhove, Onno; Zhang, Bowen; van der Sar, Dick M.; Kumar, Kundan; Pisarenco, Maxim; Rudnaya, Maria; Savceno, Valeriu; Rademacher, Jens; Zijlstra, Julia; Szabelska, Alicja; Zyprych, Joanna; van der Schans, Martin; Timperio, Vincent; Veerman, Frits; Frank, J.; van der Mei, R.; den Boer, A.; Bosman, J.; Bouman, N.; van Dam, S.; Verhoef, C.

    2010-01-01

    The wastewater from greenhouses has a high amount of mineral contamination and an environmentally-friendly method of removal is to use algae to clean this runo water. The algae consume the minerals as part of their growth process. In addition to cleaning the water, the created algal bio-mass has a

  3. Modeling and optimization of algae growth

    NARCIS (Netherlands)

    Thornton, Anthony Richard; Weinhart, Thomas; Bokhove, Onno; Zhang, Bowen; van der Sar, Dick M.; Kumar, Kundan; Pisarenco, Maxim; Rudnaya, Maria; Savcenco, Valeriu; Rademacher, Jens; Zijlstra, Julia; Szabelska, Alicja; Zyprych, Joanna; van der Schans, Martin; Timperio, Vincent; Veerman, Frits

    2010-01-01

    The wastewater from greenhouses has a high amount of mineral contamination and an environmentally-friendly method of removal is to use algae to clean this runoff water. The algae consume the minerals as part of their growth process. In addition to cleaning the water, the created algal bio-mass has a

  4. Fracture Mechanical Markov Chain Crack Growth Model

    DEFF Research Database (Denmark)

    Gansted, L.; Brincker, Rune; Hansen, Lars Pilegaard

    1991-01-01

    On the basis of the B-model developed in [J. L. Bogdanoff and F. Kozin, Probabilistic Models of Cumulative Damage. John Wiley, New York (1985)] a new numerical model incorporating the physical knowledge of fatigue crack propagation is developed. The model is based on the assumption that the crack...

  5. Separated shear-layer instability reproduction by a Reynolds stress model of turbulence

    Science.gov (United States)

    Jakirlic, Suad; Maduta, Robert

    2013-11-01

    A boundary layer separating from a solid wall transforms into a `separated shear layer' exhibiting a broader frequency range. Such a highly-unsteady shear layer separating the mean stream from the flow reversal is dominated by the organized, large-scale coherent structures, influencing to a large extent the overall flow behavior. Unlike in the case of a flat-plate boundary layer separating at a fixed point characterizing a backward-facing step geometry, which can be reasonably well captured by a statistical model of turbulence, the separation process pertinent to continuous curved surfaces as well as some fence- or rib-shaped configurations is beyond the reach of any RANS (Reynolds-Averaged Navier Stokes) model independent of the modeling level. The latter issue motivated the present work, dealing with an appropriate extension of a near-wall Second-Moment Closure (SMC) model towards an instability-sensitive formulation. The production term in the corresponding scale-supplying equation is selectively enhanced through introduction of the ratio of the first to the second derivative of the velocity field, the latter representing the integral part of the von Karman length scale, enabling appropriate capturing of the fluctuating turbulence and accordingly the reproduction of the separated shear-layer instability. The analysis is performed by simulating the flow separated from a fence, an axisymmetric hill and a cylinder configuration.

  6. The influence of caffeine and thymol on the survival, growth and reproduction of Subulina octona (Brugüière, 1789) (Mollusca, Subulinidae)

    OpenAIRE

    Ferreira,Paula; Soares,Geraldo Luiz Gonçalves; D'ávila,Sthefane; Bessa,Elisabeth Cristina de Almeida

    2009-01-01

    Subulina octona is a terrestrial snail which serves as an intermediate host for the parasites. It is also an agricultural pest. The aim of this work was to assess, during 120 days, the effects of caffeine and thymol at 2.5 g/L and 5 g/L on the hatchability, survival after hatching, growth and reproduction of S. octona under the laboratory conditions. A total of 240 eggs, 240 juveniles aged 10-day-old, and 240 aged 30-day-old were tested. The results showed that thymol (at 2.5 g/L and 5 g/L) a...

  7. Effects of three PBDEs on development, reproduction and population growth rate of the harpacticoid copepod Nitocra spinipes

    DEFF Research Database (Denmark)

    Breitholtz, M.; Wollenberger, Leah

    2003-01-01

    to the controls (***P system showed that the major fractions (&SIM; 50-80%) were associated to particulate material. Our findings indicate that development and reproduction in N. spinipes are sensitive to the tested PBDEs...... can evaluate and rate the toxic contribution from different matrices, such as suspended particles, sediment, food. water etc. (C) 2003 Elsevier Science B.V. All rights reserved....

  8. Organizing effects of adverse early-life condition on body mass, compensatory growth and reproduction : experimental studies in rock pigeons

    NARCIS (Netherlands)

    Hsu, Bin-Yan; Dijkstra, Cor; Groothuis, Ton G. G.

    Early-life food conditions can have profound impact on adult behavioural performance. In song birds, early-life food conditions affect adult physiology and cognitive performance such as song learning and spatial learning. However, effects on reproductive behaviour other than song, such as visual

  9. Extending Growth Mixture Models Using Continuous Non-Elliptical Distributions

    OpenAIRE

    Wei, Yuhong; Tang, Yang; Shireman, Emilie; McNicholas, Paul D.; Steinley, Douglas L.

    2017-01-01

    Growth mixture models (GMMs) incorporate both conventional random effects growth modeling and latent trajectory classes as in finite mixture modeling; therefore, they offer a way to handle the unobserved heterogeneity between subjects in their development. GMMs with Gaussian random effects dominate the literature. When the data are asymmetric and/or have heavier tails, more than one latent class is required to capture the observed variable distribution. Therefore, a GMM with continuous non-el...

  10. Modeling growth in arm circumference of infants in Jimma Town ...

    African Journals Online (AJOL)

    The paper models the growth in arm circumference of 450 infants during their first year of life. The model is based on longitudinal data obtained from Jimma, a town in southeast Ethiopia. A linear mixed model was employed to see how arm circumference of these infants change over their first year of life. A polynomial model ...

  11. Comparison of physical body growth and metabolic and reproductive endocrine functions between north and south climates of Japan in trained Thoroughbred yearling horses.

    Science.gov (United States)

    Tangyuenyong, Siriwan; Sato, Fumio; Nambo, Yasuo; Murase, Harutaka; Endo, Yoshiro; Tanaka, Tomomi; Nagaoka, Kentaro; Watanabe, Gen

    2017-01-01

    This study aimed to compare body growth, metabolic, and reproductive hormonal changes in trained Thoroughbred yearling horses under different climate conditions with and without light supplementation (LS). Thoroughbred yearlings raised at research centers of the Japan Racing Association in Hokkaido (north) or Miyazaki (south) were divided into control and LS groups. In the LS groups, 44 colts and 47 fillies from Hokkaido and 11 colts and 11 fillies from Miyazaki were exposed to LS with an extended photoperiod of 14.5 hr of daylight and 9.5 hr of darkness. One week before and once a month after LS, circulating total thyroxine (T4), insulin-like growth factor-I (IGF-1), prolactin (PRL), cortisol, and progesterone (P4) concentrations were measured by radioimmunoassay and fluoroimmunoassay, respectively. Growth parameters, including body weight, height, girth, and cannon bone circumferences, were measured monthly. Hair coat (HC) condition was scored. Under natural conditions, the T4 concentrations of Hokkaido yearlings tended to be higher, whereas the IGF-1 (colt) and PRL levels were significantly lower than those of yearlings in Miyazaki. Growth parameters and HC scores were lower in Hokkaido yearlings. With LS, the PRL and P4 concentrations in Hokkaido and Miyazaki were higher, and the first ovarian activity tended to be earlier than in the controls. Only LS Hokkaido yearlings showed significantly higher HC scores than the controls. Comparing the different climates among the LS yearlings, the levels of PRL and P4 and the HC scores in Hokkaido yearlings increased and reached levels similar to those in Miyazaki yearlings. The body weight and girth increment percentages of Hokkaido yearlings in January dramatically decreased and then eventually increased to levels similar to those of Miyazaki yearlings. This suggested that yearlings in naturally colder Hokkaido exhibit higher basal metabolism to maintain homeostasis. However, providing LS may help to improve growth and

  12. Modeling Root Growth, Crop Growth and N Uptake of Winter Wheat Based on SWMS_2D: Model and Validation

    Directory of Open Access Journals (Sweden)

    Dejun Yang

    Full Text Available ABSTRACT Simulations for root growth, crop growth, and N uptake in agro-hydrological models are of significant concern to researchers. SWMS_2D is one of the most widely used physical hydrologically related models. This model solves equations that govern soil-water movement by the finite element method, and has a public access source code. Incorporating key agricultural components into the SWMS_2D model is of practical importance, especially for modeling some critical cereal crops such as winter wheat. We added root growth, crop growth, and N uptake modules into SWMS_2D. The root growth model had two sub-models, one for root penetration and the other for root length distribution. The crop growth model used was adapted from EU-ROTATE_N, linked to the N uptake model. Soil-water limitation, nitrogen limitation, and temperature effects were all considered in dry-weight modeling. Field experiments for winter wheat in Bouwing, the Netherlands, in 1983-1984 were selected for validation. Good agreements were achieved between simulations and measurements, including soil water content at different depths, normalized root length distribution, dry weight and nitrogen uptake. This indicated that the proposed new modules used in the SWMS_2D model are robust and reliable. In the future, more rigorous validation should be carried out, ideally under 2D situations, and attention should be paid to improve some modules, including the module simulating soil N mineralization.

  13. Stochastic process corrosion growth models for pipeline reliability

    International Nuclear Information System (INIS)

    Bazán, Felipe Alexander Vargas; Beck, André Teófilo

    2013-01-01

    Highlights: •Novel non-linear stochastic process corrosion growth model is proposed. •Corrosion rate modeled as random Poisson pulses. •Time to corrosion initiation and inherent time-variability properly represented. •Continuous corrosion growth histories obtained. •Model is shown to precisely fit actual corrosion data at two time points. -- Abstract: Linear random variable corrosion models are extensively employed in reliability analysis of pipelines. However, linear models grossly neglect well-known characteristics of the corrosion process. Herein, a non-linear model is proposed, where corrosion rate is represented as a Poisson square wave process. The resulting model represents inherent time-variability of corrosion growth, produces continuous growth and leads to mean growth at less-than-one power of time. Different corrosion models are adjusted to the same set of actual corrosion data for two inspections. The proposed non-linear random process corrosion growth model leads to the best fit to the data, while better representing problem physics

  14. Survival, growth and reproduction of non-indigenous Nile tilapia, Oreochromis niloticus (Linnaeus 1758). I. Physiological capabilities in various temperatures and salinities

    Science.gov (United States)

    Schofield, Pamela J.; Peterson, Mark S.; Lowe, Michael R.; Brown-Peterson, Nancy J.; Slack, William T.

    2011-01-01

    The physiological tolerances of non-native fishes is an integral component of assessing potential invasive risk. Salinity and temperature are environmental variables that limit the spread of many non-native fishes. We hypothesised that combinations of temperature and salinity will interact to affect survival, growth, and reproduction of Nile tilapia, Oreochromis niloticus, introduced into Mississippi, USA. Tilapia withstood acute transfer from fresh water up to a salinity of 20 and survived gradual transfer up to 60 at typical summertime (30°C) temperatures. However, cold temperature (14°C) reduced survival of fish in saline waters ≥10 and increased the incidence of disease in freshwater controls. Although fish were able to equilibrate to saline waters in warm temperatures, reproductive parameters were reduced at salinities ≥30. These integrated responses suggest that Nile tilapia can invade coastal areas beyond their point of introduction. However, successful invasion is subject to two caveats: (1) wintertime survival depends on finding thermal refugia, and (2) reproduction is hampered in regions where salinities are ≥30. These data are vital to predicting the invasion of non-native fishes into coastal watersheds. This is particularly important given the predicted changes in coastal landscapes due to global climate change and sea-level rise.

  15. Economic Analysis of Endogenous Growth Model with ICT Capital

    OpenAIRE

    Shoji Katagiri; Hugang Han

    2014-01-01

    This paper clarifies the role of ICT capital in economic growth. Albeit ICT remarkably contributes to economic growth, there are few studies on ICT capital in ICT sector from theoretical point of view. In this paper, production function of ICT which is used as input of intermediate good in final good and ICT sectors is incorporated into our model. In this setting, we analyze the role of ICT on balance growth path and show the possibility of general equilibrium solutions f...

  16. [Integrated Quality Management System (IQMS): a model for improving the quality of reproductive health care in rural Kenya].

    Science.gov (United States)

    Herrler, Claudia; Bramesfeld, Anke; Brodowski, Marc; Prytherch, Helen; Marx, Irmgard; Nafula, Maureen; Richter-Aairijoki, Heide; Musyoka, Lucy; Marx, Michael; Szecsenyi, Joachim

    2015-01-01

    To develop a model aiming to improve the quality of services for reproductive health care in rural Kenya and designed to measure the quality of reproductive health services in such a way that allows these services to identify measures for improving their performance. The Integrated Quality Management System (IQMS) was developed on the basis of a pre-existing and validated model for quality promotion, namely the European Practice Assessment (EPA). The methodology for quality assessment and feedback of assessment results to the service teams was adopted from the EPA model. Quality assessment methodology included data assessment through staff, patient surveys and service visitation. Quality is assessed by indicators, and so indicators had to be developed that were appropriate for assessing reproductive health care in rural Kenya. A search of the Kenyan and international literature was conducted to identify potential indicators. These were then rated for their relevance and clarity by a panel of Kenyan experts. 260 indicators were rated as relevant and assigned to 29 quality dimensions and 5 domains. The implementation of IQMS in ten facilities showed that IQMS is a feasible model for assessing the quality of reproductive health services in rural Kenya. IQMS enables these services to identify quality improvement targets and necessary improvement measures. Both strengths and limitations of IQMS will be discussed. Copyright © 2015. Published by Elsevier GmbH.

  17. A smart growth evaluation model based on data envelopment analysis

    Science.gov (United States)

    Zhang, Xiaokun; Guan, Yongyi

    2018-04-01

    With the rapid spread of urbanization, smart growth (SG) has attracted plenty of attention from all over the world. In this paper, by the establishment of index system for smart growth, data envelopment analysis (DEA) model was suggested to evaluate the SG level of the current growth situation in cities. In order to further improve the information of both radial direction and non-radial detection, we introduced the non-Archimedean infinitesimal to form C2GS2 control model. Finally, we evaluated the SG level in Canberra and identified a series of problems, which can verify the applicability of the model and provide us more improvement information.

  18. Studying historical occupational careers with multilevel growth models

    Directory of Open Access Journals (Sweden)

    Wiebke Schulz

    2010-10-01

    Full Text Available In this article we propose to study occupational careers with historical data by using multilevel growth models. Historical career data are often characterized by a lack of information on the timing of occupational changes and by different numbers of observations of occupations per individual. Growth models can handle these specificities, whereas standard methods, such as event history analyses can't. We illustrate the use of growth models by studying career success of men and women, using data from the Historical Sample of the Netherlands. The results show that the method is applicable to male careers, but causes trouble when analyzing female careers.

  19. Red jungle fowl (Gallus gallus) as a model for studying the molecular mechanism of seasonal reproduction.

    Science.gov (United States)

    Ono, Hiroko; Nakao, Nobuhiro; Yamamura, Takashi; Kinoshita, Keiji; Mizutani, Makoto; Namikawa, Takao; Iigo, Masayuki; Ebihara, Shizufumi; Yoshimura, Takashi

    2009-06-01

    Photoperiodism is an adaptation mechanism that enables animals to predict seasonal changes in the environment. Japanese quail is the best model organism for studying photoperiodism. Although the recent availability of chicken genome sequences has permitted the expansion from single gene to genome-wide transcriptional analysis in this organism, the photoperiodic response of the domestic chicken is less robust than that of the quail. Therefore, in the present study, we examined the photoperiodic response of the red jungle fowl (Gallus gallus), a predecessor of the domestic chicken, to test whether this animal could be developed as an ideal model for studying the molecular mechanisms of seasonal reproduction. When red jungle fowls were transferred from short-day- to long-day conditions, gonadal development and an increase in plasma LH concentration were observed. Furthermore, rapid induction of thyrotropin beta subunit, a master regulator of photoperiodism, was observed at 16 h after dawn on the first long day. In addition, the long-day condition induced the expression of type 2 deiodinase, the key output gene of photoperiodism. These results were consistent with the results obtained in quail and suggest that the red jungle fowl could be an ideal model animal for the genome-wide transcriptional analysis of photoperiodism.

  20. Balanced growth path solutions of a Boltzmann mean field game model for knowledge growth

    KAUST Repository

    Burger, Martin

    2016-11-18

    In this paper we study balanced growth path solutions of a Boltzmann mean field game model proposed by Lucas and Moll [15] to model knowledge growth in an economy. Agents can either increase their knowledge level by exchanging ideas in learning events or by producing goods with the knowledge they already have. The existence of balanced growth path solutions implies exponential growth of the overall production in time. We prove existence of balanced growth path solutions if the initial distribution of individuals with respect to their knowledge level satisfies a Pareto-tail condition. Furthermore we give first insights into the existence of such solutions if in addition to production and knowledge exchange the knowledge level evolves by geometric Brownian motion.

  1. Reproductive Health Education Model in Early Childhood through Education Film "Damar Wulan"

    Science.gov (United States)

    Zahrulianingdyah, Atiek

    2015-01-01

    Reproductive health education for early childhood it has been the time to teach, because the demand of the changing times and will affect the child's life when he/she is a teenager. During this time, the reproductive health education, which is in it there is sex education, considered taboo among some communities. They argue that the reproductive…

  2. The aponeurotic tension model of craniofacial growth in man.

    Science.gov (United States)

    Standerwick, Richard G; Roberts, W Eugene

    2009-05-22

    Craniofacial growth is a scientific crossroad for the fundamental mechanisms of musculoskeletal physiology. Better understanding of growth and development will provide new insights into repair, regeneration and adaptation to applied loads. Traditional craniofacial growth concepts are insufficient to explain the dynamics of airway/vocal tract development, cranial rotation, basicranial flexion and the role of the cranial base in expression of facial proportions. A testable hypothesis is needed to explore the physiological pressure propelling midface growth and the role of neural factors in expression of musculoskeletal adaptation after the cessation of anterior cranial base growth. A novel model for craniofacial growth is proposed for: 1. brain growth and craniofacial adaptation up to the age of 20; 2. explaining growth force vectors; 3. defining the role of muscle plasticity as a conduit for craniofacial growth forces; and 4. describing the effect of cranial rotation in the expression of facial form.Growth of the viscerocranium is believed to be influenced by the superficial musculoaponeurotic systems (SMAS) of the head through residual tension in the occipitofrontalis muscle as a result of cephalad brain growth and cranial rotation. The coordinated effects of the regional SMAS develop a craniofacial musculoaponeurotic system (CFMAS), which is believed to affect maxillary and mandibular development.

  3. Evaluating the Predictive Value of Growth Prediction Models

    Science.gov (United States)

    Murphy, Daniel L.; Gaertner, Matthew N.

    2014-01-01

    This study evaluates four growth prediction models--projection, student growth percentile, trajectory, and transition table--commonly used to forecast (and give schools credit for) middle school students' future proficiency. Analyses focused on vertically scaled summative mathematics assessments, and two performance standards conditions (high…

  4. A grain boundary sliding model for cavitation, crack growth and ...

    African Journals Online (AJOL)

    A model is presented for cavity growth, crack propagation and fracture resulting from grain boundary sliding (GBS) during high temperature creep deformation. The theory of cavity growth by GBS was based on energy balance criteria on the assumption that the matrix is sufficiently plastic to accommodate misfit strains ...

  5. Model Selection for Nondestructive Quantification of Fruit Growth in Pepper

    NARCIS (Netherlands)

    Wubs, A.M.; Ma, Y.T.; Heuvelink, E.; Hemerik, L.; Marcelis, L.F.M.

    2012-01-01

    Quantifying fruit growth can be desirable for several purposes (e.g., prediction of fruit yield and size, or for the use in crop simulation models). The goal of this article was to determine the best sigmoid function to describe fruit growth of pepper (Capsicum annuum) from nondestructive fruit

  6. Quantification of fungal growth: models, experiment, and observations

    NARCIS (Netherlands)

    Lamour, A.

    2002-01-01

    This thesis is concerned with the growth of microscopic mycelial fungi (Section I), and that of macroscopic fungi, which form specialised hyphal structures such as rhizomorphs (Section II). A growth model is developed in Section I in relation to soil organic

  7. Modelling growth curves of Nigerian indigenous normal feather ...

    African Journals Online (AJOL)

    This study was conducted to predict the growth curve parameters using Bayesian Gompertz and logistic models and also to compare the two growth function in describing the body weight changes across age in Nigerian indigenous normal feather chicken. Each chick was wing-tagged at day old and body weights were ...

  8. Knowledge Growth: Applied Models of General and Individual Knowledge Evolution

    Science.gov (United States)

    Silkina, Galina Iu.; Bakanova, Svetlana A.

    2016-01-01

    The article considers the mathematical models of the growth and accumulation of scientific and applied knowledge since it is seen as the main potential and key competence of modern companies. The problem is examined on two levels--the growth and evolution of objective knowledge and knowledge evolution of a particular individual. Both processes are…

  9. Sexual maturity in growing dinosaurs does not fit reptilian growth models.

    Science.gov (United States)

    Lee, Andrew H; Werning, Sarah

    2008-01-15

    Recent histological studies suggest relatively rapid growth in dinosaurs. However, the timing of reproductive maturity (RM) in dinosaurs is poorly known because unambiguous indicators of RM are rare. One exception is medullary bone (MB), which is an ephemeral bony tissue that forms before ovulation in the marrow cavities of birds as a calcium source for eggshelling. Recently, MB also was described in a single specimen of the saurischian dinosaur Tyrannosaurus rex. Here, we report two other occurrences of MB: in another saurischian dinosaur, Allosaurus, and in the ornithischian dinosaur Tenontosaurus. We show by counting lines of arrested growth and performing growth curve reconstructions that Tenontosaurus, Allosaurus, and Tyrannosaurus were reproductively mature by 8, 10, and 18 years, respectively. RM in these dinosaurs coincided with a transition from growth acceleration to deceleration. It also far precedes predictions based on the growth rates of living reptiles scaled to similar size. Despite relatively rapid growth, dinosaurs were similar to reptiles in that RM developed before reaching asymptotic size. However, this reproductive strategy also occurs in medium- to large-sized mammals and correlates with a strategy of prolonged multiyear growth. RM in actively growing individuals suggests that these dinosaurs were born relatively precocial and experienced high adult mortality. The origin of the modern avian reproductive strategy in ornithuran birds likely coincided with their extreme elevations in growth rate and truncations to growth duration.

  10. DNA alterations and effects on growth and reproduction in Daphnia magna during chronic exposure to gamma radiation over three successive generations

    Energy Technology Data Exchange (ETDEWEB)

    Parisot, Florian [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France); Bourdineaud, Jean-Paul [UMR 5805 EPOC – OASU, Station marine d’Arcachon, Université Bordeaux 1, Arcachon 33120 (France); Plaire, Delphine; Adam-Guillermin, Christelle [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France); Alonzo, Frédéric, E-mail: frederic.alonzo@irsn.fr [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP-ENV/SERIS/LECO, Cadarache, St Paul-lez-Durance 13115 (France)

    2015-06-15

    Highlights: • We exposed three successive generations of Daphnia magna to chronic gamma radiation. • We examined DNA alterations and effects on survival, growth and reproduction. • DNA alterations were accumulated over a generation and transmitted to the progeny. • Effects on survival and reproduction, and delay in growth increased over generations. - Abstract: This study examined chronic effects of external Cs-137 gamma radiation on Daphnia magna exposed over three successive generations (F0, F1 and F2) to environmentally relevant dose rates (ranging from 0.007 to 35.4 mGy h{sup −1}). Investigated endpoints included survival, growth, reproduction and DNA alterations quantified using random-amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Results demonstrated that radiation effects on survival, growth and reproduction increased in severity from generation F0 to generation F2. Mortality after 21 days at 35.4 mGy h{sup −1} increased from 20% in F0 to 30% in F2. Growth was affected by a slight reduction in maximum length at 35.4 mGy h{sup −1} in F0 and by reductions of 5 and 13% in growth rate, respectively, at 4.70 and 35.4 mGy h{sup −1} in F2. Reproduction was affected by a reduction of 19% in 21 day-fecundity at 35.4 mGy h{sup −1} in F0 and by a delay of 1.9 days in brood release as low as 0.070 mGy h{sup −1} in F2. In parallel, DNA alterations became significant at decreasing dose rates over the course of F0 (from 4.70 mGy h{sup −1} at hatching to 0.007 mGy h{sup −1} after ∼21 days) and from F0 to F2 (0.070 mGy h{sup −1} at hatching to 0.007 mGy h{sup −1} after ∼21 days), demonstrating their rapid accumulation in F0 daphnids and their transmission to offspring generations. Transiently more efficient DNA repair leading to some recovery at the organism level was suggested in F1, with no effect on survival, a slight reduction of 12% in 21 day-fecundity at 35.4 mGy h{sup −1} and DNA alterations significant at highest

  11. Modeling and optimization of algae growth

    OpenAIRE

    Thornton, Anthony Richard; Weinhart, Thomas; Bokhove, Onno; Zhang, Bowen; van der Sar, Dick M.; Kumar, Kundan; Pisarenco, Maxim; Rudnaya, Maria; Savceno, Valeriu; Rademacher, Jens; Zijlstra, Julia; Szabelska, Alicja; Zyprych, Joanna; van der Schans, Martin; Timperio, Vincent

    2010-01-01

    The wastewater from greenhouses has a high amount of mineral contamination and an environmentally-friendly method of removal is to use algae to clean this runo water. The algae consume the minerals as part of their growth process. In addition to cleaning the water, the created algal bio-mass has a variety of applications including production of bio-diesel, animal feed, products for pharmaceutical and cosmetic purposes, or it can even be used as a source of heating or electricity. The aim of t...

  12. Modeling and optimization of algae growth

    OpenAIRE

    Thornton, A; Weinhart, T; Bokhove, O; Zhang, B; Sar, van der, DM; Kumar, K Kundan; Pisarenco, M Maxim; Rudnaya, M Maria; Savcenco, V Valeriu; Rademacher, JDM; Zijlstra, J; Szabelska, A; Zyprych, J; Schans, van der, M Martin; Timperio, V

    2010-01-01

    The wastewater from greenhouses has a high amount of mineral contamination and an environmentally-friendly method of removal is to use algae to clean this runoff water. The algae consume the minerals as part of their growth process. In addition to cleaning the water, the created algal bio-mass has a variety of applications including production of bio-diesel, animal feed, products for pharmaceutical and cosmetic purposes, or it can even be used as a source of heating or electricity . The aim o...

  13. 3D modeling of metallic grain growth

    Energy Technology Data Exchange (ETDEWEB)

    George, D.; Carlson, N.; Gammel, J.T.; Kuprat, A.

    1999-06-01

    This paper will describe simulating metallic grain growth using the Gradient Weighted Moving Finite Elements code, GRAIN3D. The authors also describe the set of mesh topology change operations developed to respond to changes in the physical topology such as the collapse of grains and to maintain uniform calculational mesh quality. Validation of the method is demonstrated by comparison to analytic calculations. The authors present results of multigrain simulations where grain boundaries evolve by mean curvature motion and include results which incorporate grain boundary orientation dependence.

  14. Gompertzian stochastic model with delay effect to cervical cancer growth

    International Nuclear Information System (INIS)

    Mazlan, Mazma Syahidatul Ayuni binti; Rosli, Norhayati binti; Bahar, Arifah

    2015-01-01

    In this paper, a Gompertzian stochastic model with time delay is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of cervical cancer growth. Low values of Mean-Square Error (MSE) of Gompertzian stochastic model with delay effect indicate good fits

  15. Gompertzian stochastic model with delay effect to cervical cancer growth

    Energy Technology Data Exchange (ETDEWEB)

    Mazlan, Mazma Syahidatul Ayuni binti; Rosli, Norhayati binti [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia); Bahar, Arifah [Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor and UTM Centre for Industrial and Applied Mathematics (UTM-CIAM), Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

    2015-02-03

    In this paper, a Gompertzian stochastic model with time delay is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of cervical cancer growth. Low values of Mean-Square Error (MSE) of Gompertzian stochastic model with delay effect indicate good fits.

  16. What Are Risks and Benefits of Not Incorporating Information about Population Growth and Its Impact on Climate Change into Reproductive Care?

    Science.gov (United States)

    Brown, Benjamin P; Chor, Julie

    2017-12-01

    Fears about the impact of family planning decisions on the environment are not new. Concerns about population growth have often been conflated with concerns about the increasing demographic influence of specific feared or marginalized groups, leading to subsequent unjust treatment of those targeted populations. In clinical encounters such as this case, in which the patient expresses concerns about having another child in light of the effect of population growth on climate change, it is not appropriate for the clinician to impose environmental protection values on a patient's reproductive decision making, as this risks undermining her autonomy as well as perpetuating injustice. When a patient raises such worries, however, the physician's responsibility is to elicit and try to understand the patient's preferences and then to offer treatment choices that align with those values. © 2017 American Medical Association. All Rights Reserved.

  17. The role of feeding regimens in the growth of neonate broad-banded water snakes, Nerodia fasciata confluens, and possible effects on reproduction.

    Science.gov (United States)

    Scudder, R M; Burghardt, G M

    1985-05-01

    The effect of different feeding regimens on the growth pattern of Nerodia fasciata confluens was tested using a litter of 18 captive-born neonates. The snakes were divided among three feeding groups: one group fed once per week, another fed twice per week, and the third fed on alternate days. The once per week and the twice per week groups were offered the same weight of food each week, while the alternate-day group was offered food in excess of ingestion levels during each feeding session. The results indicate that there is a shift in the allocation of energy for growth in weight, snout-vent length, and tail length with a change in the feeding regimen. Females were affected more than the males. The results are discussed in relation to their possible effect on reproduction.

  18. A new model for simulating growth in fish

    Directory of Open Access Journals (Sweden)

    Johannes Hamre

    2014-01-01

    Full Text Available A real dynamic population model calculates change in population sizes independent of time. The Beverton & Holt (B&H model commonly used in fish assessment includes the von Bertalanffy growth function which has age or accumulated time as an independent variable. As a result the B&H model has to assume constant fish growth. However, growth in fish is highly variable depending on food availability and environmental conditions. We propose a new growth model where the length increment of fish living under constant conditions and unlimited food supply, decreases linearly with increasing fish length until it reaches zero at a maximal fish length. The model is independent of time and includes a term which accounts for the environmental variation. In the present study, the model was validated in zebrafish held at constant conditions. There was a good fit of the model to data on observed growth in Norwegian spring spawning herring, capelin from the Barents Sea, North Sea herring and in farmed coastal cod. Growth data from Walleye Pollock from the Eastern Bering Sea and blue whiting from the Norwegian Sea also fitted reasonably well to the model, whereas data from cod from the North Sea showed a good fit to the model only above a length of 70 cm. Cod from the Barents Sea did not grow according to the model. The last results can be explained by environmental factors and variable food availability in the time under study. The model implicates that the efficiency of energy conversion from food decreases as the individual animal approaches its maximal length and is postulated to represent a natural law of fish growth.

  19. Interannual variability, growth, reproduction and feeding of Pelagia noctiluca (Cnidaria: Scyphozoa) in the Straits of Messina (Central Mediterranean Sea): Linkages with temperature and diet

    Science.gov (United States)

    Rosa, S.; Pansera, M.; Granata, A.; Guglielmo, L.

    2013-02-01

    To identify some of the possible environmental factors stimulating the increasingly frequent outbreaks of the scyphomedusa Pelagia noctiluca in the Straits of Messina, we investigated its abundance, growth, reproduction and feeding over a 4-year period, from 2007 to 2011, at two coastal sites. Using either field investigations and manipulative experiments we show that, among the various factors considered, shifts in water temperature (influencing medusae metabolism, growth and reproduction rates) and the size structure of the zooplankton community (their natural preys) can promote the proliferation of P. noctiluca. In particular, we show that increased temperature let jellyfishes to grow more rapidly and reach exceptional sizes. We also report a peculiar opportunistic behavior of P. noctiluca, which makes this species a potentially strong competitor in the pelagic trophic web of the Straits ecosystem. We therefore propose that more frequent P. noctiluca outbreaks stimulated by increasing sea surface temperature and shifts in their prey availability and composition would become, in the near future, a major cause of ecosystem shift.

  20. Mental models in journalistic discourse and on Facebook: the (reproduction of knowledge about #OcupeEstelita

    Directory of Open Access Journals (Sweden)

    Laura Jorge Nogueira Cavalcanti

    2016-07-01

    Full Text Available In this study we analyzed the comments written in response to a post by the action #OcupeEstelita on Facebook, and two newspaper stories in order to understand the cognitive-discursive relations established between distinct social groups. We adopted Van Dijk’s socio-cognitive perspective (2010, 2012, analyzing the categorization (LAKOFF, 1987; LANGACKER, 1987, the nominalization, and referentiation (MONDADA; DUBOIS, 2003 processes, as well as the manner how information is organized in news pieces (VAN DIJK, 1988, in order to recover the mental models created about the action, its representatives, and the social issues in question. We observed that the journalistic media tends to develop a pejorative conceptualization of the action; that the action places itself as the guardian of social-democratic interests; and that comments on Facebook tend to reproduce the same event models developed by the journalistic media. We realized, thus, that the role of conceptualization through discourse in the (reproduction of socially relevant knowledge is at stake in this discursive clash.

  1. Growth/no growth models for Zygosaccharomyces rouxii associated with acidic, sweet intermediate moisture food products.

    Science.gov (United States)

    Marvig, C L; Kristiansen, R M; Nielsen, D S

    2015-01-02

    The most notorious spoilage organism of sweet intermediate moisture foods (IMFs) is Zygosaccharomyces rouxii, which can grow at low water activity, low pH and in the presence of organic acids. Together with an increased consumer demand for preservative free and healthier food products with less sugar and fat and a traditionally long self-life of sweet IMFs, the presence of Z. rouxii in the raw materials for IMFs has made assessment of the microbiological stability a significant hurdle in product development. Therefore, knowledge on growth/no growth boundaries of Z. rouxii in sweet IMFs is important to ensure microbiological stability and aid product development. Several models have been developed for fat based, sweet IMFs. However, fruit/sugar based IMFs, such as fruit based chocolate fillings and jams, have lower pH and aw than what is accounted for in previously developed models. In the present study growth/no growth models for acidified sweet IMFs were developed with the variables aw (0.65-0.80), pH (2.5-4.0), ethanol (0-14.5% (w/w) in water phase) and time (0-90 days). Two different strains of Z. rouxii previously found to show pronounced resistance to the investigated variables were included in model development, to account for strain differences. For both strains data sets with and without the presence of sorbic acid (250 ppm on product basis) were built. Incorporation of time as an exploratory variable in the models gave the possibility to predict the growth/no growth boundaries at each time between 0 and 90 days without decreasing the predictive power of the models. The influence of ethanol and aw on the growth/no growth boundary of Z. rouxii was most pronounced in the first 30 days and 60 days of incubation, respectively. The effect of pH was almost negligible in the range of 2.5-4.0. The presence of low levels of sorbic acid (250 ppm) eliminated growth of both strains at all conditions tested. The two strains tested have previously been shown to have

  2. Solving Cocoa Pod Sigmoid Growth Model with Newton Raphson Method

    Science.gov (United States)

    Chang, Albert Ling Sheng; Maisin, Navies

    Cocoa pod growth modelling are useful in crop management, pest and disease management and yield forecasting. Recently, the Beta Growth Function has been used to determine the pod growth model due to its unique for the plant organ growth which is zero growth rate at both the start and end of a precisely defined growth period. Specific pod size (7cm to 10cm in length) is useful in cocoa pod borer (CPB) management for pod sleeving or pesticide spraying. The Beta Growth Function is well-fitted to the pods growth data of four different cocoa clones under non-linear function with time (t) as its independent variable which measured pod length and diameter weekly started at 8 weeks after fertilization occur until pods ripen. However, the same pod length among the clones did not indicate the same pod age since the morphological characteristics for cocoa pods vary among the clones. Depending on pod size for all the clones as guideline in CPB management did not give information on pod age, therefore it is important to study the pod age at specific pod sizes on different clones. Hence, Newton Raphson method is used to solve the non-linear equation of the Beta Growth Function of four different group of cocoa pod at specific pod size.

  3. Growth models for Pinus patula in Angola | Delgado-Matas ...

    African Journals Online (AJOL)

    This study developed growth models for Pinus patula Schiede ex Schltdl. et Cham. for the Central Highlands of Angola for simulating the development of stand characteristics. The model set included dominant height, individual-tree diameter increment, individual-tree height and self-thinning models. The study was based ...

  4. Modeling growth of mandibles in the Western Arctic caribou herd

    Directory of Open Access Journals (Sweden)

    Jay M. Ver Hoef

    2001-03-01

    Full Text Available We compared growth curves for ramus length and diastema length from two autumn collections of mandibles of male Western Arctic Herd caribou in Alaska. We were primarily interested in determining if growth curves of caribou mandibles differed between caribou born during 1959-1967, after the herd had been high for several years and was probably declining in size, and those born during 1976-1988, when the herd was increasing in size. To compare these growth curves, we used a nonlinear model and used maximum likelihood estimates and likelihood ratio tests. We found that growth rates were similar between periods, but intercepts and variances of growth curves differed. From this we infer that calves were smaller in autumn during the 1960s and that significant compensatory growth did not occur later in life.

  5. Regression models for linking patterns of growth to a later outcome: infant growth and childhood overweight

    Directory of Open Access Journals (Sweden)

    Andrew K. Wills

    2016-04-01

    Full Text Available Abstract Background Regression models are widely used to link serial measures of anthropometric size or changes in size to a later outcome. Different parameterisations of these models enable one to target different questions about the effect of growth, however, their interpretation can be challenging. Our objective was to formulate and classify several sets of parameterisations by their underlying growth pattern contrast, and to discuss their utility using an expository example. Methods We describe and classify five sets of model parameterisations in accordance with their underlying growth pattern contrast (conditional growth; being bigger v being smaller; becoming bigger and staying bigger; growing faster v being bigger; becoming and staying bigger versus being bigger. The contrasts are estimated by including different sets of repeated measures of size and changes in size in a regression model. We illustrate these models in the setting of linking infant growth (measured on 6 occasions: birth, 6 weeks, 3, 6, 12 and 24 months in weight-for-height-for-age z-scores to later childhood overweight at 8y using complete cases from the Norwegian Childhood Growth study (n = 900. Results In our expository example, conditional growth during all periods, becoming bigger in any interval and staying bigger through infancy, and being bigger from birth were all associated with higher odds of later overweight. The highest odds of later overweight occurred for individuals who experienced high conditional growth or became bigger in the 3 to 6 month period and stayed bigger, and those who were bigger from birth to 24 months. Comparisons between periods and between growth patterns require large sample sizes and need to consider how to scale associations to make comparisons fair; with respect to the latter, we show one approach. Conclusion Studies interested in detrimental growth patterns may gain extra insight from reporting several sets of growth pattern

  6. A Phase-Field Model for Grain Growth

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L.Q.; Fan, D.N.; Tikare, V.

    1998-12-23

    A phase-field model for grain growth is briefly described. In this model, a poly-crystalline microstructure is represented by multiple structural order parameter fields whose temporal and spatial evolutions follow the time-dependent Ginzburg-Landau (TDGL) equations. Results from phase-field simulations of two-dimensional (2D) grain growth will be summarized and preliminary results on three-dimensional (3D) grain growth will be presented. The physical interpretation of the structural order parameter fields and the efficient and accurate semi-implicit Fourier spectral method for solving the TDGL equations will be briefly discussed.

  7. Understanding pollen tube growth: the hydrodynamic model versus the cell wall model

    NARCIS (Netherlands)

    Zonia, L.; Munnik, T.

    2011-01-01

    Scientific progress stimulates the evolution of models used to understand and conceptualize biological behaviors. The widely accepted cell wall model of pollen tube growth explains stochastic growth of the apical pectin wall, but fails to explain the mechanism driving oscillations in growth and cell

  8. Another brick in the cell wall: biosynthesis dependent growth model.

    Directory of Open Access Journals (Sweden)

    Adelin Barbacci

    Full Text Available Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper.

  9. Another Brick in the Cell Wall: Biosynthesis Dependent Growth Model

    Science.gov (United States)

    Barbacci, Adelin; Lahaye, Marc; Magnenet, Vincent

    2013-01-01

    Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i) a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii) new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper. PMID:24066142

  10. Artificial Life of Soybean Plant Growth Modeling Using Intelligence Approaches

    Directory of Open Access Journals (Sweden)

    Atris Suyantohadi

    2010-03-01

    Full Text Available The natural process on plant growth system has a complex system and it has could be developed on characteristic studied using intelligent approaches conducting with artificial life system. The approaches on examining the natural process on soybean (Glycine Max L.Merr plant growth have been analyzed and synthesized in these research through modeling using Artificial Neural Network (ANN and Lindenmayer System (L-System methods. Research aimed to design and to visualize plant growth modeling on the soybean varieties which these could help for studying botany of plant based on fertilizer compositions on plant growth with Nitrogen (N, Phosphor (P and Potassium (K. The soybean plant growth has been analyzed based on the treatments of plant fertilizer compositions in the experimental research to develop plant growth modeling. By using N, P, K fertilizer compositions, its capable result on the highest production 2.074 tons/hectares. Using these models, the simulation on artificial life for describing identification and visualization on the characteristic of soybean plant growth could be demonstrated and applied.

  11. Modelling Childhood Growth Using Fractional Polynomials and Linear Splines

    Science.gov (United States)

    Tilling, Kate; Macdonald-Wallis, Corrie; Lawlor, Debbie A.; Hughes, Rachael A.; Howe, Laura D.

    2014-01-01

    Background There is increasing emphasis in medical research on modelling growth across the life course and identifying factors associated with growth. Here, we demonstrate multilevel models for childhood growth either as a smooth function (using fractional polynomials) or a set of connected linear phases (using linear splines). Methods We related parental social class to height from birth to 10 years of age in 5,588 girls from the Avon Longitudinal Study of Parents and Children (ALSPAC). Multilevel fractional polynomial modelling identified the best-fitting model as being of degree 2 with powers of the square root of age, and the square root of age multiplied by the log of age. The multilevel linear spline model identified knot points at 3, 12 and 36 months of age. Results Both the fractional polynomial and linear spline models show an initially fast rate of growth, which slowed over time. Both models also showed that there was a disparity in length between manual and non-manual social class infants at birth, which decreased in magnitude until approximately 1 year of age and then increased. Conclusions Multilevel fractional polynomials give a more realistic smooth function, and linear spline models are easily interpretable. Each can be used to summarise individual growth trajectories and their relationships with individual-level exposures. PMID:25413651

  12. A stochastic population model to evaluate Moapa dace (Moapa coriacea) population growth under alternative management scenarios

    Science.gov (United States)

    Perry, Russell W.; Jones, Edward; Scoppettone, G. Gary

    2015-07-14

    The primary goal of this research project was to evaluate the response of Moapa dace (Moapa coriacea) to the potential effects of changes in the amount of available habitat due to human influences such as ground water pumping, barriers to movement, and extirpation of Moapa dace from the mainstem Muddy River. To understand how these factors affect Moapa dace populations and to provide a tool to guide recovery actions, we developed a stochastic model to simulate Moapa dace population dynamics. Specifically, we developed an individual based model (IBM) to incorporate the critical components that drive Moapa dace population dynamics. Our model is composed of several interlinked submodels that describe changes in Moapa dace habitat as translated into carrying capacity, the influence of carrying capacity on demographic rates of dace, and the consequent effect on equilibrium population sizes. The model is spatially explicit and represents the stream network as eight discrete stream segments. The model operates at a monthly time step to incorporate seasonally varying reproduction. Growth rates of individuals vary among stream segments, with growth rates increasing along a headwater to mainstem gradient. Movement and survival of individuals are driven by density-dependent relationships that are influenced by the carrying capacity of each stream segment.

  13. Quadratic tracer dynamical models tobacco growth

    International Nuclear Information System (INIS)

    Qiang Jiyi; Hua Cuncai; Wang Shaohua

    2011-01-01

    In order to study the non-uniformly transferring process of some tracer dosages, we assume that the absorption of some tracer by tobacco is a quadratic function of the tracer quantity of the tracer in the case of fast absorption, whereas the exclusion of the tracer from tobacco is a linear function of the tracer quantity in the case of slow exclusion, after the tracer is introduced into tobacco once at zero time. A single-compartment quadratic dynamical model of Logistic type is established for the leaves of tobacco. Then, a two-compartment quadratic dynamical model is established for leaves and calms of the tobacco. Qualitative analysis of the models shows that the tracer applied to the leaves of the tobacco is excluded finally; however, the tracer stays at the tobacco for finite time. Two methods are also given for computing the parameters in the models. Finally, the results of the models are verified by the 32 P experiment for the absorption of tobacco. (authors)

  14. The Effect of Latitudinal Variation on Shrimp Reproductive Strategies.

    Science.gov (United States)

    van de Kerk, Madelon; Jones Littles, Chanda; Saucedo, Omar; Lorenzen, Kai

    2016-01-01

    Reproductive strategies comprise the timing and frequency of reproductive events and the number of offspring per reproductive event, depending on factors such as climate conditions. Therefore, species that exhibit plasticity in the allocation of reproductive effort can alter their behavior in response to climate change. Studying how the reproductive strategy of species varies along the latitudinal gradient can help us understand and predict how they will respond to climate change. We investigated the effects of the temporal allocation of reproductive effort on the population size of brown shrimp (Farfantepenaeus aztecus) along a latitudinal gradient. Multiple shrimp species exhibit variation in their reproductive strategies, and given the economic importance of brown shrimp to the commercial fishing sector of the Unites States, changes in the timing of their reproduction could have significant economic and social consequences. We used a stage-based, density-dependent matrix population model tailored to the life history of brown shrimp. Shrimp growth rates and environmental carrying capacity were varied based on the seasonal climate conditions at different latitudes, and we estimated the population size at equilibrium. The length of the growing season increased with decreasing latitude and the reproductive strategy leading to the highest population size changed from one annual birth pulse with high reproductive output to continuous low-output reproduction. Hence, our model confirms the classical paradigm of continuous reproduction at low latitudes, with increased seasonality of the breeding period towards the poles. Our results also demonstrate the potential for variation in climate to affect the optimal reproductive strategy for achieving maximum population sizes. Certainly, understanding these dynamics may inform more comprehensive management strategies for commercially important species like brown shrimp.

  15. Growth Curve Models and Applications : Indian Statistical Institute

    CERN Document Server

    2017-01-01

    Growth curve models in longitudinal studies are widely used to model population size, body height, biomass, fungal growth, and other variables in the biological sciences, but these statistical methods for modeling growth curves and analyzing longitudinal data also extend to general statistics, economics, public health, demographics, epidemiology, SQC, sociology, nano-biotechnology, fluid mechanics, and other applied areas.   There is no one-size-fits-all approach to growth measurement. The selected papers in this volume build on presentations from the GCM workshop held at the Indian Statistical Institute, Giridih, on March 28-29, 2016. They represent recent trends in GCM research on different subject areas, both theoretical and applied. This book includes tools and possibilities for further work through new techniques and modification of existing ones. The volume includes original studies, theoretical findings and case studies from a wide range of app lied work, and these contributions have been externally r...

  16. Modeling and simulation of Si crystal growth from melt

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lijun; Liu, Xin; Li, Zaoyang [National Engineering Research Center for Fluid Machinery and Compressors, School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Miyazawa, Hiroaki; Nakano, Satoshi; Kakimoto, Koichi [Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580 (Japan)

    2009-07-01

    A numerical simulator was developed with a global model of heat transfer for any crystal growth taking place at high temperature. Convective, conductive and radiative heat transfers in the furnace are solved together in a conjugated way by a finite volume method. A three-dimensional (3D) global model was especially developed for simulation of heat transfer in any crystal growth with 3D features. The model enables 3D global simulation be conducted with moderate requirement of computer resources. The application of this numerical simulator to a CZ growth and a directional solidification process for Si crystals, the two major production methods for crystalline Si for solar cells, was introduced. Some typical results were presented, showing the importance and effectiveness of numerical simulation in analyzing and improving these kinds of Si crystal growth processes from melt. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. A mathematical model of microalgae growth in cylindrical photobioreactor

    Science.gov (United States)

    Bakeri, Noorhadila Mohd; Jamaian, Siti Suhana

    2017-08-01

    Microalgae are unicellular organisms, which exist individually or in chains or groups but can be utilized in many applications. Researchers have done various efforts in order to increase the growth rate of microalgae. Microalgae have a potential as an effective tool for wastewater treatment, besides as a replacement for natural fuel such as coal and biodiesel. The growth of microalgae can be estimated by using Geider model, which this model is based on photosynthesis irradiance curve (PI-curve) and focused on flat panel photobioreactor. Therefore, in this study a mathematical model for microalgae growth in cylindrical photobioreactor is proposed based on the Geider model. The light irradiance is the crucial part that affects the growth rate of microalgae. The absorbed photon flux will be determined by calculating the average light irradiance in a cylindrical system illuminated by unidirectional parallel flux and considering the cylinder as a collection of differential parallelepipeds. Results from this study showed that the specific growth rate of microalgae increases until the constant level is achieved. Therefore, the proposed mathematical model can be used to estimate the rate of microalgae growth in cylindrical photobioreactor.

  18. Efficient experimental designs for sigmoidal growth models

    OpenAIRE

    Dette, Holger; Pepelyshev, Andrey

    2005-01-01

    For the Weibull- and Richards-regression model robust designs are determined by maximizing a minimum of D- or D1-efficiencies, taken over a certain range of the non-linear parameters. It is demonstrated that the derived designs yield a satisfactory solution of the optimal design problem for this type of model in the sense that these designs are efficient and robust with respect to misspecification of the unknown parameters. Moreover, the designs can also be used for testing the postulated for...

  19. Nonlinear modeling growth body weight of Mangalarga Marchador horses

    Directory of Open Access Journals (Sweden)

    Felipe Amorim Caetano Souza

    Full Text Available ABSTRACT: The analysis of the growth and development of various species has been done using the growth curves of the specific animal based on non-linear models. The objective of the current study was to evaluate the fit of the Brody, Gompertz, Logistic and von Bertalanffy models to the cross-sectional data of the live weight of the MangalargaMarchador horses to identify the best model and make accurate predictions regarding the growth and maturity in the males and females of this breed. The study involved recording the weight of 214 horses, of which 94 were males and 120 were non-pregnant females, between 6 and 153 months of age. The parameters of the model were estimated by employing the method of least squares, using the iteratively regularized Gauss-Newton method and the R software package. Comparison of the models was done based on the following criteria: coefficient of determination (R²; Residual Standard Deviation (RSD; corrected Akaike Information Criterion (AICc. The estimated weight of the adult horses by the models ranged between 431kg and 439kg for males and between 416kg and 420kg for females. The growth curves were studied using the cross-sectional data collection method. For males the von Bertalanffymodel was found to be the most effective in expressing growth, while in females the Brody model was more suitable. The MangalargaMarchador females achieve adult body weight earlier than the males.

  20. Reproduction and evaluation of a rat model of inhalation lung injury caused by black gunpowder smog

    Directory of Open Access Journals (Sweden)

    Yi-fan LIU

    2013-09-01

    Full Text Available Objective To reproduce and evaluate a rat model of inhalation lung injury caused by black gunpowder smog. Methods The smog composition was analyzed and a rat model of inhalation lung injury was reproduced. Forty two healthy male Wistar rats were randomly divided into normal control (NC group and 1h, 2h, 6h, 24h, 48h and 96h after inhalation group (n=6. The arterial blood gas, wet to dry weight ratio (W/D of lung, leukocyte count, and protein concentration in broncho-alveolar lavage fluid (BALF were determined. Macroscopic and microscopic changes in lung tissue were observed. Results The composition of black gunpowder smog was composed mainly of CO2 and CO, and their concentrations remained stable within 12 minutes. Smog inhalation caused a significant hypoxemia, the concentration of blood COHb reached a peak value 1h, and the W/D of lung reached peak value 2h after inhalation (P<0.05. The amount of leukocytes and content of protein in BALF increased significantly within 24h after inhalation (P<0.05. Histopathological observation showed diffuse hemorrhage, edema and inflammatory cell infiltration in lung tissue as manifestations of acute lung injury, and the injury did not recover at 96h after inhalation. Conclusion The rat model of inhalation lung injury can be reproduced using black gunpowder smog, and it has the advantages of its readiness for reproduction, reliability and stability, and it could be used for the experiment of inhalation injury in a battlefield environment.

  1. Effect of Nigella sativa on reproductive system in experimental menopause rat model

    Directory of Open Access Journals (Sweden)

    Saadat Parhizkar

    2016-01-01

    Full Text Available Objective: Menopause is the condition when regular menstrual periods cease and may be accompanied by psychological and physical symptoms. The purpose of current study was to determine Nigella sativa effects on reproductive system in experimental menopause animal models. Materials and Methods: A series of experiments wasconducted to investigate the effects of different dosages of N. sativa (first experiment, various extracts of N. sativa (second experimentand some of its ingredients (third experiment on selected menopausal parameters of ovariectomized (OVX rats. Forty different OVX rats were equally divided into 5 groups and administered with one of the following treatments for 21 days: conjugated equine estrogen (positive control, distilled water or olive oil (negative control, treatment groups  (N. sativa300, 600 and 1200 mg/kg in the first experiment, (300mg/kg methanol, hexane and SFE extracts of N. sativa in the second experiment and (linoleic acid 50 mg/kg, gamma linolenic acid 10mg/kg, and thymoquinone 15mg/kg in the third experiment. Results: The results demonstrated that N.sativa exert estrogenic effect were exhibited through uterotrophic assay and vaginal cell cornification as well as blood estrogen level. Furthermore, low dose N. sativa, methanol extract and linoleic acid had prominent estrogenic like effects which were significantly different from those of control group (p

  2. Population growth, trophic level, and reproductive biology of two congeneric archer fishes (Toxotes chatareus, Hamilton 1822 and Toxotes jaculatrix, Pallas 1767) inhabiting Malaysian coastal waters.

    Science.gov (United States)

    Simon, K D; Bakar, Y; Samat, A; Zaidi, C C; Aziz, A; Mazlan, A G

    2009-12-01

    Population growth, trophic level, and some aspects of reproductive biology of two congeneric archer fish species, Toxotes chatareus and Toxotes jaculatrix, collected from Johor coastal waters, Malaysia, were studied. Growth pattern by length-weight relationship (W=aL(b)) for the sexes differed, and exhibited positive allometric growth (male, female and combined sexes of T. chatareus; female and combined sexes of T. jaculatrix) and isometric growth (male samples of T. jaculatrix only). Trophic levels of both species were analyzed based on 128 specimens. The results show that, in both species, crustaceans and insects were the most abundant prey items, and among crustaceans the red clawed crab Sesarma bidens and Formicidae family insects were the most represented taxa. The estimated mean trophic levels for T. chatareus and T. jaculatrix were 3.422+/-0.009 and 3.420+/-0.020, respectively, indicating that they are largely carnivores. Fecundity of T. chatareus ranged from 38 354 to 147 185 eggs for females with total length ranging from 14.5 to 22.5 cm and total body weight from 48.7 to 270.2 g, and T. jaculatrix 25 251 to 150 456 eggs for females with total length ranging from 12.2 to 23.0 cm and total body weight from 25.7 to 275.0 g. Differences in values of gonadosomatic and hepatosomatic indexes calculated for both species in this study may have resulted from uneven sample size ranges.

  3. Growth and development in Syrian Awassi ewes during patterns of ovarian follicular different reproductive stages monitored by laparoscopy

    International Nuclear Information System (INIS)

    Zarkawi, M.; Soukouti, A.

    2009-06-01

    An in situ study was conducted on Syrian Awassi ewes, inside and outside the breeding season, untreated or treated with vaginal sponges together with or without equine chorionic gonadotropin aiming at monitoring the ovaries' diameters, number of different follicular categories, number, diameters and lifespan of corpora lutea in each ovary using a laparoscope and finding out the relationship among these parameters and progesterone concentration. For the first time, it has been possible to characterise the Syrian Awassi sheep at the ovarian follicles level during different reproductive stages using a laparoscope. (author)

  4. Analyses of expressed sequence tags from the maize foliar pathogen Cercospora zeae-maydis identify novel genes expressed during vegetative, infectious, and reproductive growth

    Directory of Open Access Journals (Sweden)

    Kema Gert HJ

    2008-11-01

    Full Text Available Abstract Background The ascomycete fungus Cercospora zeae-maydis is an aggressive foliar pathogen of maize that causes substantial losses annually throughout the Western Hemisphere. Despite its impact on maize production, little is known about the regulation of pathogenesis in C. zeae-maydis at the molecular level. The objectives of this study were to generate a collection of expressed sequence tags (ESTs from C. zeae-maydis and evaluate their expression during vegetative, infectious, and reproductive growth. Results A total of 27,551 ESTs was obtained from five cDNA libraries constructed from vegetative and sporulating cultures of C. zeae-maydis. The ESTs, grouped into 4088 clusters and 531 singlets, represented 4619 putative unique genes. Of these, 36% encoded proteins similar (E value ≤ 10-05 to characterized or annotated proteins from the NCBI non-redundant database representing diverse molecular functions and biological processes based on Gene Ontology (GO classification. We identified numerous, previously undescribed genes with potential roles in photoreception, pathogenesis, and the regulation of development as well as Zephyr, a novel, actively transcribed transposable element. Differential expression of selected genes was demonstrated by real-time PCR, supporting their proposed roles in vegetative, infectious, and reproductive growth. Conclusion Novel genes that are potentially involved in regulating growth, development, and pathogenesis were identified in C. zeae-maydis, providing specific targets for characterization by molecular genetics and functional genomics. The EST data establish a foundation for future studies in evolutionary and comparative genomics among species of Cercospora and other groups of plant pathogenic fungi.

  5. Rapid change in relative growth rate between the vegetative and reproductive stage of the life cycle in Plantago coronopus

    NARCIS (Netherlands)

    Koelewijn, H.P.

    2004-01-01

    A growth experiment with seedlings from Plantago coronopus, originating from small (0.13 mg) and large (0.20 mg) seeds, was conducted under optimum nutrient conditions to gain insight into the physiological processes associated with the vegetative and generative phase of plant growth. The relative

  6. Cardiometabolic and reproductive benefits of early dietary energy restriction and voluntary exercise in an obese PCOS-prone rodent model.

    Science.gov (United States)

    Diane, Abdoulaye; Kupreeva, Maria; Borthwick, Faye; Proctor, Spencer D; Pierce, W David; Vine, Donna F

    2015-09-01

    Polycystic ovary syndrome (PCOS) is one of the most common endocrine-metabolic disorders in women of reproductive age characterized by ovulatory dysfunction, hyperandrogenism and cardiometabolic risk. The overweight-obese PCOS phenotype appears to have exacerbated reproductive dysfunction and cardiometabolic risk. In overweight-obese adult women with PCOS, exercise and energy restricted diets have shown limited and inconsistent effects on both cardiometabolic indices and reproductive outcomes. We hypothesized that an early lifestyle intervention involving exercise and dietary energy restriction to prevent or reduce the propensity for adiposity would modulate reproductive indices and cardiometabolic risk in an obese PCOS-prone rodent model. Weanling obese PCOS-prone and Lean-Control JCR:LA-cp rodents were given a chow diet ad libitum or an energy-restricted diet combined with or without voluntary exercise (4  h/day) for 8 weeks. Dietary energy restriction and exercise lowered total body weight gain and body fat mass by 30% compared to free-fed sedentary or exercising obese PCOS-prone animals (PPCOS-prone animals compared to free-fed and exercise or sedentary groups. The energy restriction and exercise combination in obese PCOS-prone animals significantly increased plasma sex-hormone binding globulin, hypothalamic cocaine-and amphetamine-regulated transcript (CART) and Kisspeptin mRNA expression to levels of the Lean-Control group, and this was further associated with improvements in estrous cyclicity. The combination of exercise and dietary energy restriction when initiated in early life exerts beneficial effects on cardiometabolic and reproductive indices in an obese PCOS-prone rodent model, and this may be associated with normalization of the hypothalamic neuropeptides, Kisspeptin and CART. © 2015 Society for Endocrinology.

  7. Modeling gas exchange in a closed plant growth chamber

    Science.gov (United States)

    Cornett, J. D.; Hendrix, J. E.; Wheeler, R. M.; Ross, C. W.; Sadeh, W. Z.

    1994-01-01

    Fluid transport models for fluxes of water vapor and CO2 have been developed for one crop of wheat and three crops of soybean grown in a closed plant growth chamber. Correspondence among these fluxes is discussed. Maximum fluxes of gases are provided for engineering design requirements of fluid recycling equipment in growth chambers. Furthermore, to investigate the feasibility of generalized crop models, dimensionless representations of water vapor fluxes are presented. The feasibility of such generalized models and the need for additional data are discussed.

  8. Model for the growth of the world airline network

    Science.gov (United States)

    Verma, T.; Araújo, N. A. M.; Nagler, J.; Andrade, J. S.; Herrmann, H. J.

    2016-06-01

    We propose a probabilistic growth model for transport networks which employs a balance between popularity of nodes and the physical distance between nodes. By comparing the degree of each node in the model network and the World Airline Network (WAN), we observe that the difference between the two is minimized for α≈2. Interestingly, this is the value obtained for the node-node correlation function in the WAN. This suggests that our model explains quite well the growth of airline networks.

  9. Sensible biological models to be exposed to VDT (Video Display Terminal) radiations in human male reproduction

    International Nuclear Information System (INIS)

    Tritto, J.; North, M.-O.; Laverdure, A.M.; Surbeck, J.

    1999-01-01

    Temperature and environmental effects, particularly endocrine disrupters and EMF radiations, are actively investigated in human and non-human reproduction experimental models. Sensitivity and specificity of the different cell types of the testes seminiferous tubules in animals and in human are evaluated, showing a specific responsiveness of spermatogonia (SPG) and resting pachytene spermatocytes (SPC). At 32 o C the 24 h short-term cultures of biopsies of normal human testis show an expected low occurrence of apoptotic SPG (1 %) that increases to 3,4 % in peer samples exposed to VDT for the same period, with the appearance of apoptotic SPC (4,6 %). In samples from a thermically-impaired testis of the same subject the apoptotic occurrence of SPG is 2,6 % with 15,4 % for SPC after 24 h cultures. After 24 h exposure to VDT the apoptotic score is 7,6 % for SPG and 18,5 % for SPC in thermically impaired peer samples. With EMF-bioshields the apoptotic score for SPG is 0,8 % in normal 2,2 % for SPG and 13,8 % for SPC in T-impaired peer-samples. NMRS of the cultures fluids show a proportional production of lactate, corresponding to the different degrees of histopathological impairment of the samples. IVOS (Integrated Visual Optic System) analysis of sperm samples from thermically-impaired, not-repaired and repaired testes exposed to VDT shows sensible variations on straightness (STR), linearity (LIN) and lateral head displacement (LHD) parameters. To evaluate the thermic and non-thermic potential bioeffects of VDT on human spermatogenesis the specificity, the sensitivity and the reproducibility of the biological models on one side and the specificity of the methodologies on the other side must be provided. (author)

  10. Using Calculus to Model the Growth of L. Plantarum Bacteria

    Directory of Open Access Journals (Sweden)

    Erin Carey

    2009-01-01

    Full Text Available Experimental data for the growth of Lactobacillus plantarum bacteria have been obtained over time, creating the need for mathematical means to model this data. We use the Gompertz model because it is a sigmoid function for a time series, where growth is slowest at the start and end of a time period. The Gompertz model is especially useful because it defines specific parameters that characterize the S-shaped curve. In addition, the Gompertz model uses relative growth, which is the logarithm of the given population compared to the initial population. This reflects the fact that bacteria grow exponentially. The important parameters that were found were the lag time and the asymptote.

  11. Double sigmoidal models describing the growth of coffee berries

    Directory of Open Access Journals (Sweden)

    Tales Jesus Fernandes

    Full Text Available ABSTRACT: This study aimed to verify if the growth pattern of coffee berries, considering fresh mass accumulation over time, is double sigmoid and to select the most suitable nonlinear model to describe such behavior. Data used consisted of fourteen longitudinal observations of average fresh mass of coffee berries obtained in an experiment with the cultivar Obatã IAC 1669-20. The fits provided by the Logistic and Gompertz models were compared in their single and double versions. Parameters were estimated using the least squares method using the Gauss-Newton algorithm implemented in the nls function of the R software. It can be concluded that the growth pattern of the coffee fruit, in fresh mass accumulation, is double sigmoid. The double Gompertz and double Logistic models were adequate to describe such a growth curve, with a superiority of the double Logistic model.

  12. Modelling primary branch growth based on a multilevel nonlinear ...

    African Journals Online (AJOL)

    In addition to random effects, various time series correlation structures were evaluated to account for residual autocorrelation, and the AR(1) and ARMA(1,1) structures were selected for the branch diameter and length growth models, respectively. Model validation results using an independent data set confirmed that ...

  13. Probabilistic Model for Fatigue Crack Growth in Welded Bridge Details

    DEFF Research Database (Denmark)

    Toft, Henrik Stensgaard; Sørensen, John Dalsgaard; Yalamas, Thierry

    2013-01-01

    In the present paper a probabilistic model for fatigue crack growth in welded steel details in road bridges is presented. The probabilistic model takes the influence of bending stresses in the joints into account. The bending stresses can either be introduced by e.g. misalignment or redistributio...

  14. Crustal growth at active continental margins: Numerical modeling

    NARCIS (Netherlands)

    Vogt, Katharina; Gerya, Taras; Castro, Antonio

    The dynamics and melt sources for crustal growth at active continental margins are analyzed by using a 2D coupled petrological–thermomechanical numerical model of an oceanic-continental subduction zone. This model includes spontaneous slab retreat and bending, dehydration of subducted crust, aqueous

  15. Surface-bounded growth modeling applied to human mandibles

    DEFF Research Database (Denmark)

    Andresen, Per Rønsholt; Brookstein, F. L.; Conradsen, Knut

    2000-01-01

    automatically using shape features and a new algorithm called geometry-constrained diffusion. The semilandmarks are mapped into Procrustes space. Principal component analysis extracts a one-dimensional subspace, which is used to construct a linear growth model. The worst case mean modeling error in a cross...

  16. Kinetic models of cell growth, substrate utilization and bio ...

    African Journals Online (AJOL)

    Bio-decolorization kinetic studies of distillery effluent in a batch culture were conducted using Aspergillus fumigatus. A simple model was proposed using the Logistic Equation for the growth, Leudeking-Piret kinetics for bio-decolorization, and also for substrate utilization. The proposed models appeared to provide a suitable ...

  17. Modelling diameter growth, mortality and recruitment of trees in ...

    African Journals Online (AJOL)

    Miombo woodlands cover large areas in Tanzania but very little reliable data on forest dynamics for the woodlands exist. The main objective of this study was to develop a model system describing such dynamics based on easily measurable tree variables. Individual tree diameter growth and mortality models, and ...

  18. Comparison of four nonlinear growth models for effective exploration ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    2016-10-05

    Oct 5, 2016 ... This study was conducted to compare the effectiveness for non-linear growth models designated as. Chapman-Richards, Gompertz, Logistic and von Bertalanffy for selection of fast-growing fish strain of turbot Scophthalmus maximus. These models were compared using the goodness of fit (the coefficient.

  19. Modeling nano-scale grain growth of intermetallics

    Indian Academy of Sciences (India)

    Administrator

    Abstract. The Monte Carlo simulation is utilized to model the nano-scale grain growth of two nano- crystalline materials, Pd81Zr19 and RuAl. In this regard, the relationship between the real time and the time unit of simulation, i.e. Monte Carlo step (MCS), is determined. The results of modeling show that with increasing time ...

  20. Growth models for six Eucalyptus species in Angola | Delgado ...

    African Journals Online (AJOL)

    This study developed growth models for Eucalyptus saligna Sm., E. camaldulensis Dehnh., E. macarthurii H.Deane & Maiden, E. resinifera Sm., E. siderophloia Benth. and E. grandis Hill ex. Maiden, for the central highlands of Angola, and used these models to simulate the development of stand characteristics.

  1. Comparison of four nonlinear growth models for effective exploration ...

    African Journals Online (AJOL)

    This study was conducted to compare the effectiveness for non-linear growth models designated as Chapman-Richards, Gompertz, Logistic and von Bertalanffy for selection of fast-growing fish strain of turbot Scophthalmus maximus. These models were compared using the goodness of fit (the coefficient of determination ...

  2. Species distribution models as a tool to estimate reproductive parameters: a case study with a passerine bird species.

    Science.gov (United States)

    Brambilla, Mattia; Ficetola, Gentile F

    2012-07-01

    1. Correlative species distribution models (SDMs) assess relationships between species distribution data and environmental features, to evaluate the environmental suitability (ES) of a given area for a species, by providing a measure of the probability of presence. If the output of SDMs represents the relationships between habitat features and species performance well, SDM results can be related also to other key parameters of populations, including reproductive parameters. To test this hypothesis, we evaluated whether SDM results can be used as a proxy of reproductive parameters (breeding output, territory size) in red-backed shrikes (Lanius collurio). 2. The distribution of 726 shrike territories in Northern Italy was obtained through multiple focused surveys; for a subset of pairs, we also measured territory area and number of fledged juveniles. We used Maximum Entropy modelling to build a SDM on the basis of territory distribution. We used generalized least squares and spatial generalized mixed models to relate territory size and number of fledged juveniles to SDM suitability, while controlling for spatial autocorrelation. 3. Species distribution models predicted shrike distribution very well. Territory size was negatively related to suitability estimated through SDM, while the number of fledglings significantly increased with the suitability of the territory. This was true also when SDM was built using only spatially and temporally independent data. 4. Results show a clear relationship between ES estimated through presence-only SDMs and two key parameters related to species' reproduction, suggesting that suitability estimated by SDM, and habitat quality determining reproduction parameters in our model system, are correlated. Our study shows the potential use of SDMs to infer important fitness parameters; this information can have great importance in management and conservation. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological

  3. Regressional modeling and forecasting of economic growth for arkhangelsk region

    Directory of Open Access Journals (Sweden)

    Robert Mikhailovich Nizhegorodtsev

    2012-12-01

    Full Text Available The regression models of GRP, considering the impact of three main factors: investment in fixed assets, wages amount, and, importantly, the innovation factor –the expenditures for research and development, are constructed in this paper on the empirical data for Arkhangelsk region. That approach permits to evaluate explicitly the contribution of innovation to economic growth. Regression analysis is the main research instrument, all calculations areperformedin the Microsoft Excel. There were made meaningful conclusions regarding the potential of the region's GRP growth by various factors, including impacts of positive and negative time lags. Adequate and relevant models are the base for estimation and forecasting values of the dependent variable (GRP and evaluating their confidence intervals. The invented method of research can be used in factor assessment and prediction of regional economic growth, including growth by expectations.

  4. Surface detail reproduction and dimensional accuracy of stone models: influence of disinfectant solutions and alginate impression materials.

    Science.gov (United States)

    Guiraldo, Ricardo Danil; Borsato, Thaís Teixeira; Berger, Sandrine Bittencourt; Lopes, Murilo Baena; Gonini, Alcides; Sinhoreti, Mário Alexandre Coelho

    2012-01-01

    This study compared the surface detail reproduction and dimensional accuracy of stone models obtained from molds disinfected with 2% sodium hypochlorite, 2% chlorhexidine digluconate or 0.2% peracetic acid to models produced using molds which were not disinfected, with 3 alginate materials (Cavex ColorChange, Hydrogum 5 and Jeltrate Plus). The molds were prepared over matrix containing 20-, 50-, and 75-µm lines, performed under pressure with perforated metal tray. The molds were removed following gelation and either disinfected (using one of the solutions by spraying followed by storage in closed jars for 15 min) or not disinfected. The samples were divided into 12 groups (n=5). Molds were filled with dental gypsum Durone IV and 1 h after the start of the stone mixing the models were separated from the tray. Surface detail reproduction and dimensional accuracy were evaluated using optical microscopy on the 50-µm line with 25 mm in length, in accordance with the ISO 1563 standard. The dimensional accuracy results (%) were subjected to ANOVA. The 50 µm-line was completely reproduced by all alginate impression materials regardless of the disinfection procedure. There was no statistically significant difference in the mean values of dimensional accuracy in combinations between disinfectant procedure and alginate impression material (p=0.2130) or for independent factors. The disinfectant solutions and alginate materials used in this study are no factors of choice regarding the surface detail reproduction and dimensional accuracy of stone models.

  5. Spending Natural Resource Revenues in an Altruistic Growth Model

    DEFF Research Database (Denmark)

    Frederiksen, Elisabeth Hermann

    This paper examines how revenues from a natural resource interact with growth and welfare in an overlapping generations model with altruism. The revenues are allocated between public productive services and direct transfers to members of society by spending policies. We analyze how these policies...... influence the dynamics, and how the dynamics are influenced by the abundance of the revenue. Abundant revenues may harm growth, but growth and welfare can be oppositely affected. We also provide the socially optimal policy. Overall, the analysis suggests that variation in the strength of altruism...... and in spending policies may be part of the reason why natural resources seem to affect economic performance across nations differently...

  6. A thermodynamic model for growth mechanisms of multiwall carbon nanotubes.

    Energy Technology Data Exchange (ETDEWEB)

    Kaatz, Forrest H.; Overmyer, Donald L.; Siegal, Michael P.

    2006-02-01

    Multiwall carbon nanotubes are grown via thermal chemical vapor deposition between temperatures of 630 and 830 C using acetylene in nitrogen as the carbon source. This process is modeled using classical thermodynamics to explain the total carbon deposition as a function of time and temperature. An activation energy of 1.60 eV is inferred for nanotube growth after considering the carbon solubility term. Scanning electron microscopy shows growth with diameters increasing linearly with time. Transmission electron microscopy and Raman spectroscopy show multiwall nanotubes surrounded by a glassy-carbon sheath, which grows with increasing wall thickness as growth temperatures and times rise.

  7. Thermodynamic model for growth mechanisms of multiwall carbon nanotubes

    Science.gov (United States)

    Kaatz, F. H.; Siegal, M. P.; Overmyer, D. L.; Provencio, P. P.; Tallant, D. R.

    2006-12-01

    Multiwall carbon nanotubes are grown via thermal chemical vapor deposition between temperatures of 630 and 830°C using acetylene in nitrogen as the carbon source. This process is modeled using classical thermodynamics to explain the total carbon deposition as a function of time and temperature. An activation energy of 1.60eV is inferred for nanotube growth after considering the carbon solubility term. Scanning electron microscopy shows growth with diameters increasing linearly with time. Transmission electron microscopy and Raman spectroscopy show multiwall nanotubes surrounded by a glassy-carbon sheath, which grows with increasing wall thickness as growth temperatures and times rise.

  8. Government technology push in agribusiness: a model of endogenous growth

    Directory of Open Access Journals (Sweden)

    Francisco Venegas Martínez

    2008-10-01

    Full Text Available This paper develops a model of endogenous growth where the government acts as a promoting agent to boost technology in agribusiness. In the framework of a monetary economy, the optimal level of government spending to enhance technology in the agricultural industry is characterized. Moreover the impact of such a spending on economic welfare is assessed. Finally, a number of agro-oriented policies to increase growth in the sector are established.

  9. Human growth and body weight dynamics: an integrative systems model.

    Science.gov (United States)

    Rahmandad, Hazhir

    2014-01-01

    Quantifying human weight and height dynamics due to growth, aging, and energy balance can inform clinical practice and policy analysis. This paper presents the first mechanism-based model spanning full individual life and capturing changes in body weight, composition and height. Integrating previous empirical and modeling findings and validated against several additional empirical studies, the model replicates key trends in human growth including A) Changes in energy requirements from birth to old ages. B) Short and long-term dynamics of body weight and composition. C) Stunted growth with chronic malnutrition and potential for catch up growth. From obesity policy analysis to treating malnutrition and tracking growth trajectories, the model can address diverse policy questions. For example I find that even without further rise in obesity, the gap between healthy and actual Body Mass Indexes (BMIs) has embedded, for different population groups, a surplus of 14%-24% in energy intake which will be a source of significant inertia in obesity trends. In another analysis, energy deficit percentage needed to reduce BMI by one unit is found to be relatively constant across ages. Accompanying documented and freely available simulation model facilitates diverse applications customized to different sub-populations.

  10. Modeling of spatial variations of growth within apical domes by means of the growth tensor. II. Growth specified on dome surface

    Directory of Open Access Journals (Sweden)

    Zygmunt Hejnowicz

    2014-01-01

    Full Text Available Variations of the elemental relative rate of growth are modeled for parabolic, elliptic and hyperbolic domes of shoot apices by using the growth tensor in a suitable curvilinear coordinate system when the mode of area growth on the dome surface is known. Variations of growth rates within the domes are obtained in forms of computer-made maps for the following variants of growth on the dome surface: (1 constant meridional growth rate, (2 isotropic area growth, (3 anisotropy of area growth which becomes more intensive with increasing distance from the vertex. In variants 1 and 2 a maximum of volumetric growth rate appears in the center of the dome. Such a distribution of growth seems to be unrealistic. However, the corresponding growth tensors are interesting because they can be used in combination with other growth tensors to get the expected minimum volumetric growth rate in the dome center.

  11. Potts-model grain growth simulations: Parallel algorithms and applications

    Energy Technology Data Exchange (ETDEWEB)

    Wright, S.A.; Plimpton, S.J.; Swiler, T.P. [and others

    1997-08-01

    Microstructural morphology and grain boundary properties often control the service properties of engineered materials. This report uses the Potts-model to simulate the development of microstructures in realistic materials. Three areas of microstructural morphology simulations were studied. They include the development of massively parallel algorithms for Potts-model grain grow simulations, modeling of mass transport via diffusion in these simulated microstructures, and the development of a gradient-dependent Hamiltonian to simulate columnar grain growth. Potts grain growth models for massively parallel supercomputers were developed for the conventional Potts-model in both two and three dimensions. Simulations using these parallel codes showed self similar grain growth and no finite size effects for previously unapproachable large scale problems. In addition, new enhancements to the conventional Metropolis algorithm used in the Potts-model were developed to accelerate the calculations. These techniques enable both the sequential and parallel algorithms to run faster and use essentially an infinite number of grain orientation values to avoid non-physical grain coalescence events. Mass transport phenomena in polycrystalline materials were studied in two dimensions using numerical diffusion techniques on microstructures generated using the Potts-model. The results of the mass transport modeling showed excellent quantitative agreement with one dimensional diffusion problems, however the results also suggest that transient multi-dimension diffusion effects cannot be parameterized as the product of the grain boundary diffusion coefficient and the grain boundary width. Instead, both properties are required. Gradient-dependent grain growth mechanisms were included in the Potts-model by adding an extra term to the Hamiltonian. Under normal grain growth, the primary driving term is the curvature of the grain boundary, which is included in the standard Potts-model Hamiltonian.

  12. Growth, reproductive phenology and yield responses of a potential biofuel plant, Jatropha curcas grown under projected 2050 levels of elevated CO2.

    Science.gov (United States)

    Kumar, Sumit; Chaitanya, Bharatula S K; Ghatty, Sreenivas; Reddy, Attipalli R

    2014-11-01

    Jatropha (Jatropha curcas) is a non-edible oil producing plant which is being advocated as an alternative biofuel energy resource. Its ability to grow in diverse soil conditions and minimal requirements of essential agronomical inputs compared with other oilseed crops makes it viable for cost-effective advanced biofuel production. We designed a study to investigate the effects of elevated carbon dioxide concentration ([CO(2)]) (550 ppm) on the growth, reproductive development, source-sink relationships, fruit and seed yield of J. curcas. We report, for the first time that elevated CO(2) significantly influences reproductive characteristics of Jatropha and improve its fruit and seed yields. Net photosynthetic rate of Jatropha was 50% higher in plants grown in elevated CO(2) compared with field and ambient CO(2) -grown plants. The study also revealed that elevated CO(2) atmosphere significantly increased female to male flower ratio, above ground biomass and carbon sequestration potential in Jatropha (24 kg carbon per tree) after 1 year. Our data demonstrate that J. curcas was able to sustain enhanced rate of photosynthesis in elevated CO(2) conditions as it had sufficient sink strength to balance the increased biomass yields. Our study also elucidates that the economically important traits including fruit and seed yield in elevated CO(2) conditions were significantly high in J. curcas that holds great promise as a potential biofuel tree species for the future high CO(2) world. © 2014 Scandinavian Plant Physiology Society.

  13. Dietary exposure of mink (Mustela vison) to fish from the Housatonic River, Berkshire County, Massachusetts, USA: Effects on reproduction, kit growth, and survival

    Science.gov (United States)

    Bursian, S.J.; Sharma, C.; Aulerich, R.J.; Yamini, B.; Mitchell, R.R.; Orazio, C.E.; Moore, D.R.J.; Svirsky, S.; Tillitt, D.E.

    2006-01-01

    We evaluated the effects of feeding farm-raised mink (Mustela vison) diets containing polychlorinated biphenyl (PCB)-contaminated fish from the Housatonic River (HR; Berkshire County, MA, USA) on adult reproductive performance and kit growth and survival. Diets contained 0.22-3.54% HR fish, providing 0.34-3.7 ??g total PCBs (TPCB)/g feed wet wt (3.5-68.5 pg toxic equivalence [TEQ]/g). Female mink were fed diets before breeding through weaning of kits. Twelve kits from each treatment were maintained on their respective diets for an additional 180 d. Dietary PCBs had no effect on the number of offspring produced, gestation period, or other measures of adult reproductive performance. Mink kits exposed to 3.7 ??g TPCB/g feed (68.5 pg TEQ/g) in utero and during lactation had reduced survivability between three and six weeks of age. The lethal concentrations to 10 and 20% of the population (LC10 and LC20, respectively) were estimated to be 0.231 and 0.984 ??g TPCB/g feed, respectively. Because inclusion of PCB-contaminated fish that composed approximately 1% of the diet would reduce mink kit survival by 20% or more, it is likely that consumption of up to 30-fold that quantity of HR fish, as could be expected for wild mink, would have an adverse effect on wild mink populations. ?? 2006 SETAC.

  14. Theories of Socio-Cultural Reproduction.

    Science.gov (United States)

    Passeron, Jean-Claude

    1986-01-01

    Examines various sociological theories of socio-cultural reproduction, devoting special attention to the role of education. Differentiates historical repetition from social reproduction and develops a social-reproduction model. (JDH)

  15. Reproductive Science for High School Students: A Shared Curriculum Model to Enhance Student Success.

    Science.gov (United States)

    Castle, Megan; Cleveland, Charlotte; Gordon, Diana; Jones, Lynda; Zelinski, Mary; Winter, Patricia; Chang, Jeffrey; Senegar-Mitchell, Ericka; Coutifaris, Christos; Shuda, Jamie; Mainigi, Monica; Bartolomei, Marisa; Woodruff, Teresa K

    2016-07-01

    The lack of a national reproductive biology curriculum leads to critical knowledge gaps in today's high school students' comprehensive understanding of human biology. The Oncofertility Consortium developed curricula that address the basic and clinical aspects of reproductive biology. Launching this academy and creating easy-to-disseminate learning modules allowed other universities to implement similar programs across the country. The expansion of this informal, extracurricular academy on reproductive health from Northwestern University to the University of California, San Diego, Oregon Health & Science University, and the University of Pennsylvania magnifies the scope of scientific learning to students who might not otherwise be exposed to this important information. To assess the experience gained from this curriculum, we polled alumni from the four centers. Data were collected anonymously from de-identified users who elected to self-report on their experiences in their respective reproductive science academy. The alumni survey asked participants to report on their current academic standing, past experiences in the academy, and future academic and career goals. The results of this national survey suggest the national oncofertility academies had a lasting impact on participants and may have contributed to student persistence in scientific learning. © 2016 by the Society for the Study of Reproduction, Inc.

  16. Age, growth, mortality, reproduction and feeding habits of the striped seabream, Lithognathus mormyrus (Pisces: Sparidae in the coastal waters of the Thracian Sea, Greece

    Directory of Open Access Journals (Sweden)

    Argyris Kallianiotis

    2005-09-01

    Full Text Available Age, growth, mortality, reproduction and feeding habits were analysed for Lithognathus mormyrus collected in the coastal waters of the Thracian Sea from November 1997 to September 1999. Specimens ranged from 42 to 341 mm in total length. Weight increased with size allometrically (b = 3.242 for immature individuals and isometrically (b = 2.960 for males, females and intersexuals. Growth was described by the standard form of the von Bertalanffy growth equation and the estimated parameters were k = 0.21, t0 = –0.996 and L? = 309.4. Total and natural instantaneous rate of mortality was found to be Z = 0.79 year-1 and M = 0.61 year-1. Sex inversion occurred mainly between 210 and 300 mm (4-9 age classes. Males reached sexual maturity at 162.1 mm (2.5 years and females at 190.40 mm (3.6 years. The spawning period occurred from May to September, while the gamete emission peaked in June-August. Stomach content analysis revealed that L. mormyrus is a carnivorous species feeding on benthic invertebrates, mainly polychaeta and bivalve molluscs. Ontogenetic variation in the diet composition showed that while growing, the fish become more generalist feeders. We also found that in the summer season the fish become more selective feeders.

  17. Single nucleotide polymorphisms in BMPR-IB and STAT5B genes and their association with growth and reproductive traits in chicken

    Directory of Open Access Journals (Sweden)

    Shahram Niknafs

    2014-04-01

    Full Text Available The aim of the current study was to investigate the association of G4533815A SNP in STAT5B and A287G SNP in BMPR-IB genes with growth and reproduction related traits in chicken. A sample of 205 individuals from breeding station of Mazandaran native chicken population was selected randomly. All of the individuals were genotyped for both SNPs using PCR-RFLP technique. Marker-trait association analyses were performed using estimated breeding value of the traits as dependent variable in GLM procedure of SAS 9.1. Results suggested that breeding value least square means for genotypes of G4533815A SNP is significantly differed from each other for traits of body weight at 8 and 12 weeks (P<0.01. In the case of BMPR-IB gene, no significant difference was found. In conclusion, STAT5B gene may be associated with body growth in chicken and may be considered in Marker Assisted Selection program to improve chicken growth performance.

  18. Baseline growth and reproductive parameters in Lymnaea stagnalis for OECD test guideline development: optimization of diets and culturing conditions

    DEFF Research Database (Denmark)

    Holbech, Henrik; Hutchinson, Tom

    The OECD has successfully validated reproductive toxicity test guidelines with fish and frogs for diverse chemicals (including endocrine disrupters). Since molluscs are especially sensitive to chronic exposure to a number of chemicals, the OECD supports the complementary development and validation...... laboratories in Denmark, Germany and the UK for the OECD pre-validation work to date. Laboratory cultures of L. stagnalis are traditionally fed fresh (preferably organic) lettuce; however, interrupted supplies of fresh lettuce in some countries in 2011 highlighted a potential problem for the draft OECD test...... guideline. Therefore, we have evaluated other diets based on a review of the published literature and report here the results for different feeds: namely, cabbage leaves, fish flakes, lettuce leaves or sliced sweet potato. For the feeding trial, 5 snails (shell size ca. 2.6 cm) were held in 1 L freshwater...

  19. Modeling bacterial population growth from stochastic single-cell dynamics.

    Science.gov (United States)

    Alonso, Antonio A; Molina, Ignacio; Theodoropoulos, Constantinos

    2014-09-01

    A few bacterial cells may be sufficient to produce a food-borne illness outbreak, provided that they are capable of adapting and proliferating on a food matrix. This is why any quantitative health risk assessment policy must incorporate methods to accurately predict the growth of bacterial populations from a small number of pathogens. In this aim, mathematical models have become a powerful tool. Unfortunately, at low cell concentrations, standard deterministic models fail to predict the fate of the population, essentially because the heterogeneity between individuals becomes relevant. In this work, a stochastic differential equation (SDE) model is proposed to describe variability within single-cell growth and division and to simulate population growth from a given initial number of individuals. We provide evidence of the model ability to explain the observed distributions of times to division, including the lag time produced by the adaptation to the environment, by comparing model predictions with experiments from the literature for Escherichia coli, Listeria innocua, and Salmonella enterica. The model is shown to accurately predict experimental growth population dynamics for both small and large microbial populations. The use of stochastic models for the estimation of parameters to successfully fit experimental data is a particularly challenging problem. For instance, if Monte Carlo methods are employed to model the required distributions of times to division, the parameter estimation problem can become numerically intractable. We overcame this limitation by converting the stochastic description to a partial differential equation (backward Kolmogorov) instead, which relates to the distribution of division times. Contrary to previous stochastic formulations based on random parameters, the present model is capable of explaining the variability observed in populations that result from the growth of a small number of initial cells as well as the lack of it compared to

  20. Influence of alginate impression materials and storage time on surface detail reproduction and dimensional accuracy of stone models.

    Science.gov (United States)

    Guiraldo, Ricardo D; Moreti, Ana F F; Martinelli, Julia; Berger, Sandrine B; Meneghel, Luciana L; Caixeta, Rodrigo V; Sinhoreti, Mário A C

    2015-01-01

    This study compared the surface detail reproduction and dimensional accuracy of stone models obtained from molds prepared using different alginate impression materials (Cavex ColorChange, Hydrogum 5, or Jeltrate Plus) and with different storage times (1, 3, and 5 days) to models from molds that were filled immediately with no storage time. The molds were prepared over a matrix containing 50-μm line, (ISO 1563 standard) under pressure with a perforated metal tray. The molds were removed 2 minutes after loss of sticky consistency and either filled immediately or stored in closed jars at 100% relative humidity and 37°C for 1, 3, or 5 days. The molds were filled with dental plaster (Durone IV). Surface detail reproduction and dimensional accuracy were evaluated using optical microscopy on the 50-μm wide line, which was 25 mm in length, according to ISO 1563 standard. The dimensional accuracy results (%) were subjected to analysis of variance. The 50-μm wide line (ISO 1563 standard) was completely reproduced by all alginate impression materials regardless of the storage time. There was no statistically significant difference in the mean dimensional accuracy values of stone models made from molds composed of different alginate impression materials and with different storage times (p = 0.989). In conclusion, storing the mold for five days prior to filling did not change the surface detail reproduction or dimensional accuracy of the alginates examined in this study.