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.

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.

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

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...... their target height (sd score) at 3 yr of age [mean -0.91 (1.2)], compared with NC children [-0.61 (0.9), P = 0.033]. In the child cohort, target height attainment (sd score) and growth factors did not differ among the three groups. CONCLUSIONS: The overall growth pattern of ICSI and IVF children in both...... 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...

Symbiotic regulation of plant growth, development and reproduction

Science.gov (United States)

Rodriguez, R.J.; Freeman, D. Carl; McArthur, E.D.; Kim, Y.-O.; Redman, R.S.

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 five times the rate observed in nonsymbiotic plants. Endophytes also influenced sexual reproduction of mature big sagebrush (Artemisia tridentata) plants. Two spatially distinct big sagebrush subspecies and their hybrids were symbiotic with unique fungal endophytes, despite being separated by only 380 m distance and 60 m elevation. A double reciprocal transplant experiment of parental and hybrid plants, and soils across the hybrid zone showed that fungal endophytes interact with the soils and different plant genotypes to confer enhanced plant reproduction in soil native to the endophyte and reduced reproduction in soil alien to the endophyte. Moreover, the most prevalent endophyte of the hybrid zone reduced the fitness of both parental subspecies. Because these endophytes are passed to the next generation of plants on seed coats, this interaction provides a selective advantage, habitat specificity, and the means of restricting gene flow, thereby making the hybrid zone stable, narrow and potentially leading to speciation. ?? 2009 Landes Bioscience.

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.

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

Science.gov (United States)

Reis, Carla R G; Taddei, Fabiano G; Cobo, Valter J

2015-01-01

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.

Genetic correlations among and between wool, growth and reproduction traits in Merino sheep.

Science.gov (United States)

Safari, E; Fogarty, N M; Gilmour, A R; Atkins, K D; Mortimer, S I; Swan, A A; Brien, F D; Greeff, J C; van der Werf, J H J

2007-04-01

Data from seven research resource flocks across Australia were combined to provide accurate estimates of genetic correlations among production traits in Merino sheep. The flocks represented contemporary Australian Merino fine, medium and broad wool strains over the past 30 years. Over 110,000 records were available for analysis for each of the major wool traits, and 50,000 records for reproduction and growth traits with over 2700 sires and 25,000 dams. Individual models developed from the single trait analyses were extended to the various combinations of two-trait models to obtain genetic correlations among six wool traits [clean fleece weight (CFW), greasy fleece weight, fibre diameter (FD), yield, coefficient of variation of fibre diameter and standard deviation of fibre diameter], four growth traits [birth weight, weaning weight, yearling weight (YWT), and hogget weight] and four reproduction traits [fertility, litter size, lambs born per ewe joined, lambs weaned per ewe joined (LW/EJ)]. This study has provided for the first time a comprehensive matrix of genetic correlations among these 14 wool, growth and reproduction traits. The large size of the data set has also provided estimates with very low standard errors. A moderate positive genetic correlation was observed between CFW and FD (0.29 +/- 0.02). YWT was positively correlated with CFW (0.23 +/- 0.04), FD (0.17 +/- 0.04) and LWEJ (0.58 +/- 0.06), while LW/EJ was negatively correlated with CFW (-0.26 +/- 0.05) and positively correlated with FD (0.06 +/- 0.04) and LS (0.68 +/- 0.04). These genetic correlations, together with the estimates of heritability and other parameters provide the basis for more accurate prediction of outcomes in complex sheep-breeding programmes designed to improve several traits.

Environmental Influences on Growth and Reproduction of Invasive Commelina benghalensis

Directory of Open Access Journals (Sweden)

Mandeep K. Riar

2016-01-01

Full Text Available Commelina benghalensis (Benghal dayflower is a noxious weed that is invading agricultural systems in the southeastern United States. We investigated the influences of nutrition, light, and photoperiod on growth and reproductive output of C. benghalensis. In the first experimental series, plants were grown under high or low soil nutrition combined with either full light or simulated shade. Lowered nutrition strongly inhibited vegetative growth and aboveground spathe production. Similar but smaller effects were exerted by a 50% reduction in light, simulating conditions within a developing canopy. In the second series of experiments, C. benghalensis plants were exposed to different photoperiod conditions that produced short- and long-day plants growing in similar photosynthetic periods. A short-day photoperiod decreased time to flowering by several days and led to a 40 to 60% reduction in vegetative growth, but reproduction above and below ground was unchanged. Collectively, the results indicate that (1 fertility management in highly weathered soils may strongly constrain competitiveness of C. benghalensis; (2 shorter photoperiods will limit vegetative competitiveness later in the growing seasons of most crops; and (3 the high degree of reproductive plasticity and output possessed by C. benghalensis will likely cause continual persistence problems in agricultural fields.

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 ...

Growth and reproductive investment of introduced Pacific oysters

NARCIS (Netherlands)

Cardoso, J.F.M.F.; Peralta, N.R.E.; Machado, J.P.; van der Veer, H.W.

2013-01-01

Growth and reproductive investment of cultured Pacific oysters Crassostrea gigas were studied in two south-western European estuaries: the Ria 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

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

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...... 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...

Growth and male reproduction improvement of non-thermal dielectric barrier discharge plasma treatment on chickens

Science.gov (United States)

Jiao Zhang, Jiao; Luong Huynh, Do; Chandimali, Nisansala; Kang, Tae Yoon; Kim, Nameun; Mok, Young Sun; Kwon, Taeho; Jeong, Dong Kee

2018-05-01

This study investigated whether plasma treatment of fertilized eggs before hatching could affect the growth and reproduction of chickens. Three point five-day-incubated fertilized eggs exposed to non-thermal dielectric barrier discharge plasma at 2.81 W of power for 2 min resulted in the highest growth in chickens. Plasma growth-promoting effect was regulated by the reactive oxygen species homeostasis and the improvement of energy metabolism via increasing serum hormones and adenosine triphosphate levels which were resulted from the regulation of genes involved in antioxidant defense, hormone biosynthesis and energetic metabolism. Interestingly, plasma-treated male chickens conspicuously grew faster than females. Further, aspects of male reproductive system (testosterone level and sperm quality) were improved by the plasma treatment but female reproduction (estradiol and progesterone levels, egg-laying rate and egg weight) had no significant changes. Unfortunately, offspring whose parents were the optimal plasma-treated chickens did not show any difference on growth characteristics and failed to inherit excellent growth features from their parents. Our results suggest a new method to improve the growth rate and male reproductive capacity in poultry but it is only effective in the plasma direct-treated generation.

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

Science.gov (United States)

Kefford, Ben J; Nugegoda, Dayanthi

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 microS/cm; reproduction: deionized water, 100, 500, 1000 and 3000 microS/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 microS/cm. The number of eggs produced per snail per day was maximal between 100 and 1000 microS/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.

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.

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

Science.gov (United States)

Peña Messina, Emilio; Tapia Varela, Raul; Velázquez Abunader, José Iván; Orbe Mendoza, Alma Araceli; Velazco Arce, Javier Marcial de Jesús Ruiz

2010-12-01

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 2413 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 infinity 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 (b overfishing. Blue tilapia reproduces year-round; the highest activity occurs from January through May and size of first maturity was 23 cm SL. We conclude that it is necessary to establish a minimum catch size in this reservoir based on the reproductive behavior of this species.

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

International Nuclear Information System (INIS)

Kefford, Ben J.; Nugegoda, Dayanthi

2005-01-01

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 μS/cm; reproduction: deionized water, 100, 500, 1000 and 3000 μS/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 μS/cm. The number of eggs produced per snail per day was maximal between 100 and 1000 μS/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

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 (b<3. Significant differences were found between SL/TW model for the sexes, suggesting separate models for males and females. Results indicate that there are no differences in growth rates between sexes; the proposed parameters were L∞=43.33cm standard length, k=0.36/year and t0=-0.43years. Natural and fishing mortality coefficients were 0.83/year and 1.10/year, respectively. The estimated exploitation rate (0.57/year suggested that during the study period the fishery showed signs of overfishing. Blue tilapia reproduces year-round; the highest activity occurs from January through May and size of first maturity was 23cm SL. We conclude that it is necessary to establish a minimum catch size in this reservoir based on the reproductive behavior of this species. Rev. Biol. Trop. 58 (4: 1577-1586. Epub 2010 December 01.

Testing mechanistic models of growth in insects.

Science.gov (United States)

Maino, James L; Kearney, Michael R

2015-11-22

Insects are typified by their small size, large numbers, impressive reproductive output and rapid growth. However, insect growth is not simply rapid; rather, insects follow a qualitatively distinct trajectory to many other animals. Here we present a mechanistic growth model for insects and show that increasing specific assimilation during the growth phase can explain the near-exponential growth trajectory of insects. The presented model is tested against growth data on 50 insects, and compared against other mechanistic growth models. Unlike the other mechanistic models, our growth model predicts energy reserves per biomass to increase with age, which implies a higher production efficiency and energy density of biomass in later instars. These predictions are tested against data compiled from the literature whereby it is confirmed that insects increase their production efficiency (by 24 percentage points) and energy density (by 4 J mg(-1)) between hatching and the attainment of full size. The model suggests that insects achieve greater production efficiencies and enhanced growth rates by increasing specific assimilation and increasing energy reserves per biomass, which are less costly to maintain than structural biomass. Our findings illustrate how the explanatory and predictive power of mechanistic growth models comes from their grounding in underlying biological processes. © 2015 The Author(s).

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.

Local variability in growth and reproduction of Salix arctica in the High Arctic

Directory of Open Access Journals (Sweden)

Noémie Boulanger-Lapointe

2016-06-01

Full Text Available Arctic terrestrial ecosystems are heterogeneous because of the strong influences of microtopography, soil moisture and snow accumulation on vegetation distribution. The interaction between local biotic and abiotic factors and global climate patterns will influence species responses to climate change. Salix arctica (Arctic willow is a structuring species, ubiquitous and widespread, and as such is one of the most important shrub species in the High Arctic. In this study, we measured S. arctica reproductive effort, early establishment, survival and growth in the Zackenberg valley, north-east Greenland. We sampled four plant communities that varied with respect to snow conditions, soil moisture, nutrient content and plant composition. We found large variability in reproductive effort and success with total catkin density ranging from 0.6 to 66 catkins/m2 and seedling density from <1 to 101 seedlings/m2. There were also major differences in crown area increment (4–23 cm2/year and stem radial growth (40–74 µm/year. The snowbed community, which experienced a recent reduction in snow cover, supported young populations with high reproductive effort, establishment and growth. Soil nutrient content and herbivore activity apparently did not strongly constrain plant reproduction and growth, but competition by Cassiope tetragona and low soil moisture may inhibit performance. Our results show that local environmental factors, such as snow accumulation, have a significant impact on tundra plant response to climate change and will affect the understanding of regional vegetation response to climate change.

[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.

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.

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

Effect of uranium on growth and reproduction of the marine amphipod Allorchestes compressa

International Nuclear Information System (INIS)

Ahsanullah, M.; Williams, A.R.

1986-01-01

Experiments on growth of the marine amphipod Allorchestes compressa Dana were carried out over four weeks, and both growth and reproduction were studied over three generations, each of which was exposed to uranium for approximately 10 wk. At 0.1 mg l -1 the uranium increased growth by 23%, as measured by the mean weight after 4 wk, and at 2 mg l -1 growth was reduced by 28% compared with the control. A. compressa accumulated uranium from sea water with a concentration factor of 10. There was no effect of uranium on the survival of amphipods or their progeny in the multiple-generation experiment, but the numbers of males, the sex ratio, and the respiration rate (measured on males only) at 1 mg l -1 were significantly lower than the control. A. compressa is shown to be a convenient species for the study of toxic effects on growth and reproduction using multiple-generation experiments. (orig.)

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.

The influence of bacteria-dominated diets on Daphnia magna somatic growth, reproduction, and lipid composition.

Science.gov (United States)

Taipale, Sami J; Brett, Michael T; Pulkkinen, Katja; Kainz, Martin J

2012-10-01

We explored how dietary bacteria affect the life history traits and biochemical composition of Daphnia magna, using three bacteria taxa with very different lipid composition. Our objectives were to (1) examine whether and how bacteria-dominated diets affect Daphnia survival, growth, and fecundity, (2) see whether bacteria-specific fatty acid (FA) biomarkers accrued in Daphnia lipids, and (3) explore the quantitative relationship between bacteria availability in Daphnia diets and the amounts of bacterial FA in their lipids. Daphnia were fed monospecific and mixed diets of heterotrophic (Micrococcus luteus) or methanotrophic bacteria (Methylomonas methanica and Methylosinus trichosporium) and two phytoplankton species (Cryptomonas ozolinii and Scenedesmus obliquus). Daphnia neonates fed pure bacteria diets died after 6-12 days and produced no viable offspring, whereas those fed pure phytoplankton diets had high survival, growth, and reproduction success. Daphnia fed a mixed diet with 80% M. luteus and 20% of either phytoplankton had high somatic growth, but low reproduction. Conversely, Daphnia fed mixed diets including 80% of either methane-oxidizing bacteria and 20% Cryptomonas had high reproduction rates, but low somatic growth. All Daphnia fed mixed bacteria and phytoplankton diets had strong evidence of both bacteria- and phytoplankton-specific FA biomarkers in their lipids. FA mixing model calculations indicated that Daphnia that received 80% of their carbon from bacteria assimilated 46 ± 25% of their FA from this source. A bacteria-phytoplankton gradient experiment showed a strong positive correlation between the proportions of the bacterial FA in the Daphnia and their diet, indicating that bacterial utilization can be traced in this keystone consumer using FA biomarkers. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

[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.

Energetic Constraints on Fungal Growth.

Science.gov (United States)

Heaton, Luke L M; Jones, Nick S; Fricker, Mark D

2016-02-01

Saprotrophic fungi are obliged to spend energy on growth, reproduction, and substrate digestion. To understand the trade-offs involved, we developed a model that, for any given growth rate, identifies the strategy that maximizes the fraction of energy that could possibly be spent on reproduction. Our model's predictions of growth rates and bioconversion efficiencies are consistent with empirical findings, and it predicts the optimal investment in reproduction, resource acquisition, and biomass recycling for a given environment and timescale of reproduction. Thus, if the timescale of reproduction is long compared to the time required for the fungus to double in size, the model suggests that the total energy available for reproduction is maximal when a very small fraction of the energy budget is spent on reproduction. The model also suggests that fungi growing on substrates with a high concentration of low-molecular-weight compounds will not benefit from recycling: they should be able to grow more rapidly and allocate more energy to reproduction without recycling. In contrast, recycling offers considerable benefits to fungi growing on recalcitrant substrates, where the individual hyphae are not crowded and the time taken to consume resource is significantly longer than the fungus doubling time.

Does the silver moss Bryum argenteum exhibit sex-specific patterns in vegetative growth rate, asexual fitness or prezygotic reproductive investment?

Science.gov (United States)

Horsley, Kimberly; Stark, Lloyd R; McLetchie, D Nicholas

2011-05-01

Expected life history trade-offs associated with sex differences in reproductive investment are often undetected in seed plants, with the difficulty arising from logistical issues of conducting controlled experiments. By controlling genotype, age and resource status of individuals, a bryophyte was assessed for sex-specific and location-specific patterns of vegetative, asexual and sexual growth/reproduction across a regional scale. Twelve genotypes (six male, six female) of the dioecious bryophyte Bryum argenteum were subcultured to remove environmental effects, regenerated asexually to replicate each genotype 16 times, and grown over a period of 92 d. Plants were assessed for growth rates, asexual and sexual reproductive traits, and allocation to above- and below-ground regenerative biomass. The degree of sexual versus asexual reproductive investment appears to be under genetic control, with three distinct ecotypes found in this study. Protonemal growth rate was positively correlated with asexual reproduction and sexual reproduction, whereas asexual reproduction was negatively correlated (appeared to trade-off) with vegetative growth (shoot production). No sex-specific trade-offs were detected. Female sex-expressing shoots were longer than males, but the sexes did not differ in growth traits, asexual traits, sexual induction times, or above- and below-ground biomass. Males, however, had much higher rates of inflorescence production than females, which translated into a significantly higher (24x) prezygotic investment for males relative to females. Evidence for three distinct ecotypes is presented for a bryophyte based on regeneration traits. Prior to zygote production, the sexes of this bryophyte did not differ in vegetative growth traits but significantly differed in reproductive investment, with the latter differences potentially implicated in the strongly biased female sex ratio. The disparity between males and females for prezygotic reproductive investment is

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

International Nuclear Information System (INIS)

Tieszen, Chelsea R; Goyeneche, Alicia A; Brandhagen, BreeAnn N; Ortbahn, Casey T; Telleria, Carlos M

2011-01-01

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. 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. 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. 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 apoptotic lethality at higher doses in association with increased

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

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.

Reproduction numbers of infectious disease models

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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

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.

) were performed using 30 nm citric acid stabilized AgNP. The aim of the study was, besides providing data for the chronic toxicity of AgNP, to study the influence of the food availability on the reproductive toxicity of AgNP in Daphnia magna. The exposure concentrations applied ranged from 2 to 50 μg...... to controls, whereas concentrations above 10 μgAg/L resulted in inhibition of growth and reproduction as well as an increased mortality. The addition of higher amounts of food showed a beneficial effect on animal survival, growth and reproduction. Similar as in normal food availability treatment, animals......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...

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

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. PMID:24132088

A model for growth of a single fungal hypha based on well-mixed tanks in series: simulation of nutrient and vesicle transport in aerial reproductive hyphae.

Science.gov (United States)

Balmant, Wellington; Sugai-Guérios, Maura Harumi; Coradin, Juliana Hey; Krieger, Nadia; Furigo Junior, Agenor; Mitchell, David Alexander

2015-01-01

Current models that describe the extension of fungal hyphae and development of a mycelium either do not describe the role of vesicles in hyphal extension or do not correctly describe the experimentally observed profile for distribution of vesicles along the hypha. The present work uses the n-tanks-in-series approach to develop a model for hyphal extension that describes the intracellular transport of nutrient to a sub-apical zone where vesicles are formed and then transported to the tip, where tip extension occurs. The model was calibrated using experimental data from the literature for the extension of reproductive aerial hyphae of three different fungi, and was able to describe different profiles involving acceleration and deceleration of the extension rate. A sensitivity analysis showed that the supply of nutrient to the sub-apical vesicle-producing zone is a key factor influencing the rate of extension of the hypha. Although this model was used to describe the extension of a single reproductive aerial hypha, the use of the n-tanks-in-series approach to representing the hypha means that the model has the flexibility to be extended to describe the growth of other types of hyphae and the branching of hyphae to form a complete mycelium.

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.

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.

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.

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.

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

International Nuclear Information System (INIS)

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

2017-01-01

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.

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

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.

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; ...

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

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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.

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.)

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

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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.

Growth and Reproduction of Artificially Fed Cnaphalocrocis medinalis

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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.

Sex-specific impact of prenatal stress on growth and reproductive parameters of guinea pigs.

Science.gov (United States)

Schöpper, Hanna; Klaus, Teresa; Palme, Rupert; Ruf, Thomas; Huber, Susanne

2012-12-01

Body condition and reproductive maturation are parameters of reproductive success that are influenced by sexual hormones rising in the circulation during the time of puberty. Various endocrine systems can be programmed by conditions experienced during early life. Stress for instance is supposed to be capable of influencing fetal development, leading to adjustments of offspring's later physiology. We examined whether prenatal stress (induced by exposure to strobe light) during early- to mid-gestation was capable of affecting later reproductive parameters in guinea pigs (Cavia aperea f. porcellus). Therefore, we measured the levels of testosterone and progesterone from the age of day 12-124 in prenatally stressed (PS, n = 20) and unaffected control animals (n = 24). Furthermore, we determined the timing of puberty and growth. Body weight development revealed significantly faster growth in PS females compared to control animals. The onset of first estrus was slightly earlier in PS females, however not significantly so. Cycle lengths and levels of progesterone differed between groups over the course of time with higher progesterone levels and more constant cycles among PS females compared to control females who displayed marked differences between first and subsequent cycles. Levels of testosterone did not differ between groups. We conclude that prenatal stress accelerates growth and maturity in females, but not in males.

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)

Nutrient allocations and metabolism in two Collembola with contrasting reproduction and growth strategies

DEFF Research Database (Denmark)

Larsen, Thomas; Ventura, Marc; Damgaard, Christian

2009-01-01

1.  Physiological mechanisms such as allocation and release of nutrients are keys to understanding an animal's adaptation to a particular habitat. This study investigated how two detrivores with contrasting life-history traits allocated carbon (C) and nitrogen (N) to growth, reproduction and meta...

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

An empirical test of evolutionary theories for reproductive senescence and reproductive effort in the garter snake Thamnophis elegans.

Science.gov (United States)

Sparkman, Amanda M; Arnold, Stevan J; Bronikowski, Anne M

2007-04-07

Evolutionary theory predicts that differential reproductive effort and rate of reproductive senescence will evolve under different rates of external mortality. We examine the evolutionary divergence of age-specific reproduction in two life-history ecotypes of the western terrestrial garter snake, Thamnophis elegans. We test for the signature of reproductive senescence (decreasing fecundity with age) and increasing reproductive effort with age (increasing reproductive productivity per gram female) in replicate populations of two life-history ecotypes: snakes that grow fast, mature young and have shorter lifespans, and snakes that grow slow, mature late and have long lives. The difference between life-history ecotypes is due to genetic divergence in growth rate. We find (i) reproductive success (live litter mass) increases with age in both ecotypes, but does so more rapidly in the fast-growth ecotype, (ii) reproductive failure increases with age in both ecotypes, but the proportion of reproductive failure to total reproductive output remains invariant, and (iii) reproductive effort remains constant in fast-growth individuals with age, but declines in slow-growth individuals. This illustration of increasing fecundity with age, even at the latest ages, deviates from standard expectations for reproductive senescence, as does the lack of increases in reproductive effort. We discuss our findings in light of recent theories regarding the phenomenon of increased reproduction throughout life in organisms with indeterminate growth and its potential to offset theoretical expectations for the ubiquity of senescence.

Demographic consequences of greater clonal than sexual reproduction in Dicentra canadensis.

Science.gov (United States)

Lin, Chia-Hua; Miriti, Maria N; Goodell, Karen

2016-06-01

Clonality is a widespread life history trait in flowering plants that may be essential for population persistence, especially in environments where sexual reproduction is unpredictable. Frequent clonal reproduction, however, could hinder sexual reproduction by spatially aggregating ramets that compete with seedlings and reduce inter-genet pollination. Nevertheless, the role of clonality in relation to variable sexual reproduction in population dynamics is often overlooked. We combined population matrix models and pollination experiments to compare the demographic contributions of clonal and sexual reproduction in three Dicentra canadensis populations, one in a well-forested landscape and two in isolated forest remnants. We constructed stage-based transition matrices from 3 years of census data to evaluate annual population growth rates, λ. We used loop analysis to evaluate the relative contribution of different reproductive pathways to λ. Despite strong temporal and spatial variation in seed set, populations generally showed stable growth rates. Although we detected some pollen limitation of seed set, manipulative pollination treatments did not affect population growth rates. Clonal reproduction contributed significantly more than sexual reproduction to population growth in the forest remnants. Only at the well-forested site did sexual reproduction contribute as much as clonal reproduction to population growth. Flowering plants were more likely to transition to a smaller size class with reduced reproductive potential in the following year than similarly sized nonflowering plants, suggesting energy trade-offs between sexual and clonal reproduction at the individual level. Seed production had negligible effects on growth and tuber production of individual plants. Our results demonstrate that clonal reproduction is vital for population persistence in a system where sexual reproduction is unpredictable. The bias toward clonality may be driven by low fitness returns

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.

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

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.

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.

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.

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.

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...

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

Seasonal timing in a warming world : Plasticity of seasonal timing of growth and reproduction

NARCIS (Netherlands)

Salis, Lucia

2015-01-01

In seasonal environments the timing of various biological processes is crucial for growth, survival and reproductive success of an individual. Nowadays, rapid large-scale climate change is altering species’ seasonal timing (phenology) in many eco¬systems. In this thesis Lucia Salis focuses on the

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

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.

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

Effects of food availability on growth and reproduction of the deep-sea pedunculate barnacle Heteralepas canci

Science.gov (United States)

Yasuda, Natsumi; Miyamoto, Norio; Fujiwara, Yoshihiro; Yamamoto, Tomoko; Yusa, Yoichi

2016-02-01

Sessile animals living on continental shelves or slopes may adjust their growth and reproduction according to temporally and spatially variable food availability, but little information is available on these animals to date. We collected the pedunculate barnacle Heteralepas canci on a continental slope at a depth of 229 m off Cape Nomamisaki in southern Japan. We developed a rearing method for the barnacles and studied their growth and reproduction at different food levels in the laboratory. A total of 136 individual H. canci were fed with Artemia salina larvae and brewer's yeast at three different food levels for 100 days. Both the growth and the ovary development were delayed when food availability was low, whereas the survival rate was lower at the high food level. In addition, an individual survived under complete starvation for 167 days. We concluded that H. canci has plastic life history traits that are adaptive for variable food availability.

Modeling effects of cadmium on population growth of Palaemonetes pugio: Results of a full life cycle exposure

International Nuclear Information System (INIS)

Manyin, Teresa; Rowe, Christopher L.

2008-01-01

In an 8-month laboratory experiment, Palaemonetes pugio (grass shrimp) were exposed to aqueous cadmium (free cadmium ion concentrations of 1.51 or 2.51 μg Cd 2+ /L) for an entire life cycle, from larva to reproductive adult and through to production of second-generation larva. Individual-level effects on survival, life stage duration, and reproduction were measured, and population growth was projected using two models: a stage-based matrix model and a z-transformed life cycle graph analysis. Adult survival was significantly reduced at 2.51 μg Cd 2+ /L, but cadmium exposure had no effects on survival or stage duration of embryos, larvae, or juveniles. Survival of second-generation larvae was unaffected by maternal exposure. Brood size was reduced by 27% at 1.51 μg Cd 2+ /L and by 36% at 2.51 μg Cd 2+ /L. The percent of females in the population that was gravid was approximately 50% lower at 2.51 μg Cd 2+ /L, compared to controls. Both population models projected a dose-dependent decrease in population growth rate (λ), up to a 12% reduction at 2.51 μg Cd 2+ /L, which can be attributed mainly to contributions from reproductive effects. Elasticity analysis revealed that population growth rate was most sensitive to changes in survival of juveniles and adults. However, lethal effects of cadmium made only a small contribution to the effect on population growth rate. Even though both models project positive growth (λ > 1) of grass shrimp populations exposed to low concentrations of cadmium, the ability of populations to withstand predation pressure would be compromised

Modeling effects of cadmium on population growth of Palaemonetes pugio: Results of a full life cycle exposure

Energy Technology Data Exchange (ETDEWEB)

Manyin, Teresa [University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, PO Box 38, 1 Williams Street, Solomons, MD 20688 (United States)], E-mail: manyin@cbl.umces.edu; Rowe, Christopher L. [University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, PO Box 38, 1 Williams Street, Solomons, MD 20688 (United States)

2008-06-23

In an 8-month laboratory experiment, Palaemonetes pugio (grass shrimp) were exposed to aqueous cadmium (free cadmium ion concentrations of 1.51 or 2.51 {mu}g Cd{sup 2+}/L) for an entire life cycle, from larva to reproductive adult and through to production of second-generation larva. Individual-level effects on survival, life stage duration, and reproduction were measured, and population growth was projected using two models: a stage-based matrix model and a z-transformed life cycle graph analysis. Adult survival was significantly reduced at 2.51 {mu}g Cd{sup 2+}/L, but cadmium exposure had no effects on survival or stage duration of embryos, larvae, or juveniles. Survival of second-generation larvae was unaffected by maternal exposure. Brood size was reduced by 27% at 1.51 {mu}g Cd{sup 2+}/L and by 36% at 2.51 {mu}g Cd{sup 2+}/L. The percent of females in the population that was gravid was approximately 50% lower at 2.51 {mu}g Cd{sup 2+}/L, compared to controls. Both population models projected a dose-dependent decrease in population growth rate ({lambda}), up to a 12% reduction at 2.51 {mu}g Cd{sup 2+}/L, which can be attributed mainly to contributions from reproductive effects. Elasticity analysis revealed that population growth rate was most sensitive to changes in survival of juveniles and adults. However, lethal effects of cadmium made only a small contribution to the effect on population growth rate. Even though both models project positive growth ({lambda} > 1) of grass shrimp populations exposed to low concentrations of cadmium, the ability of populations to withstand predation pressure would be compromised.

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: r...

Impact of habitat variability and altitude on growth dynamics and reproductive allocation in Ferula jaeschkeana Vatke

Directory of Open Access Journals (Sweden)

Ubaid Yaqoob

2017-01-01

Full Text Available Ferula jaeschkeana Vatke is an important threatened medicinal plant of the Himalayan region. The present study was carried out to determine the impact of the habitat variability and altitudinal gradient on the morphological and reproductive features of the species under study. The species exhibited great variability in its morphological traits under different environmental conditions. The plants were more vigorous and taller at a low altitude site, Kashmir University Botanical Garden (KUBG while the plants of a high altitude site, Gulmarg were shorter. With increased altitude, a significant reduction in the number of umbels per flowering stem, umbellules per umbel and flowers per umbellule occurred. An increase in the number of stigma and anthers was also observed in some plants at higher altitudes. Principal component analysis (PCA revealed that the habitat of KUBG and Dachigam proved relatively better for the growth of F. jaeschkeana. Maximum resources were allocated to the growth and development of the stem followed by root tubers, leaves and inflorescence. Reproductive success of the plant species varied along the altitudinal gradient and ranged from 64% to 72%. Increasing altitude resulted in a decrease in the allocation of biomass to reproductive structures in the form of decreasing dry weight. The total resource budget per plant was maximum in low altitude Drang (572.6 ± 158.36 g and Dachigam (568.4 ± 133.42 g populations and was least in the Gulmarg population (333.4 ± 82.89 g. The reproductive effort was higher (50.83% for the high altitude Gulmarg population. The regression analysis revealed a positive correlation and predicts that plant height has a direct impact on the umbel diameter and leaf length. Our results present a detailed account on the variation of growth characteristics, reproductive success and changes in allocation patterns in relation to the environmental conditions of this valuable medicinal plant species

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.

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.

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

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.

Temperature affects brain and pituitary gene expression related to reproduction and growth in the male blue gouramis, Trichogaster trichopterus.

Science.gov (United States)

David, Dalia; Degani, Gad

2011-04-01

This study examined the effect of temperature on reproduction and growth-related factors in blue gourami males under nonreproductive and reproductive conditions. Males that were maintained under nonreproductive conditions did not build nest and the gonado-somatic index (% GSI) was significantly higher in fish maintained at 27°C compared with fish maintained at 23°C. The relative mRNA levels of brain gonadotropin-releasing hormone 3 (GnRH3), pituitary adenylate cyclase-activating polypeptide (PACAP), insulin-like growth factor-1(IGF-1), pituitary β-luteinizing hormone (βLH), and prolactin were significantly higher when the fish were maintained at 27°C than at 23°C or 31°C. β-Follicle-stimulating hormone (βFSH) mRNA levels were significantly lower when maintained at 31°C than at the other temperatures. Nests were observed only in males under reproductive conditions. In these fish, higher mRNA levels of GnRH3, PACAP, βFSH, βLH and prolactin were detected at 27°C, and higher mRNA levels of IGF-1 were detected at 23°C, when compared with other temperature of maintenance or with fish that did not build nest. In conclusion, we propose that temperature has more effect on the transcription of genes, associated with reproduction, than on those pertaining to growth. Copyright © 2011 Wiley-Liss, Inc., A Wiley Company.

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

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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.

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

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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

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.

The dynamics of reproductive rate, offspring survivorship and growth in the lined seahorse, Hippocampus erectus Perry, 1810

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Qiang Lin

2012-02-01

Seahorses are the vertebrate group with the embryonic development occurring within a special pouch in males. To understand the reproductive efficiency of the lined seahorse, Hippocampus erectus Perry, 1810 under controlled breeding experiments, we investigated the dynamics of reproductive rate, offspring survivorship and growth over births by the same male seahorses. The mean brood size of the 1-year old pairs in the 1st birth was 85.4±56.9 per brood, which was significantly smaller than that in the 6th birth (465.9±136.4 per brood (P<0.001. The offspring survivorship and growth rate increased with the births. The fecundity was positively correlated with the length of brood pouches of males and trunk of females. The fecundity of 1-year old male and 2-year old female pairs was significantly higher than that from 1-year old couples (P<0.001. The brood size (552.7±150.4 of the males who mated with females that were isolated for the gamete-preparation, was larger than those (467.8±141.2 from the long-term pairs (P<0.05. Moreover, the offspring from the isolated females had higher survival and growth rates. Our results showed that the potential reproductive rate of seahorses H. erectus increased with the brood pouch development.

Influence of season of birth on growth and reproductive development of Brahman bulls.

Science.gov (United States)

Tatman, Shawn R; Neuendorff, Don A; Wilson, Timothy W; Randel, Ronald D

2004-07-01

Seasonal effects on reproduction are more dramatic in Bos indicus than Bos taurus cattle. This experiment evaluated reproductive development of fall- (n=7) versus spring- (n = 10) born Brahman bulls to determine if season of birth affects reproductive development. Measurements of growth and reproductive development began after weaning and continued at bi-weekly intervals until each bull reached sexual maturity. Different stages of sexual development were classified according to characteristics of the ejaculate and included first sperm in the ejaculate, puberty (> 50 x 10(6) sperm/ejaculate), and sexual maturity (two ejaculates with > 500 = 10(6) sperm/ejaculate). Average daily increases in all measured traits were similar in fall- and spring-born bulls and there were no differences in age, body weight, scrotal circumference, or paired testis volume between groups at first sperm or puberty. However, fall-born bulls were older (P days versus 481 days, respectively) as the interval between puberty and sexual maturity was longer (P days versus 54 days, respectively). The prolonged interval between puberty and sexual maturity in fall-born calves coincided with a short photoperiod (winter) whereas the short interval between puberty and sexual maturity in spring-born calves coincided with a long photoperiod (summer). In conclusion, season of birth affected sexual development; photoperiod might be involved in regulating testicular function immediately after puberty in Brahman bulls.

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...

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

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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.

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

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...

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.

Growth and reproductive performance of sambar deer in Sabal Forest Reserve of Sarawak, Malaysia.

Science.gov (United States)

Dahlan, Ismail; Dawend, Jiwan

2013-10-01

We examined the growth, reproduction, rutting behavior, and health status of sambar deer (Cervus unicolor brookei) in secondary Acacia mangium plantation. The data were collected over 11 years from a breeding herd of 21 stags and 33 hinds in Sabal Forest Reserve, Sarawak, Malaysia. Brody's growth model of the pooled data is Y t  = 148.56 (1 - 0.98e(-0.023t)), which estimates that maximum weights of adults are 184 and 115 kg for males and females respectively. Sambar deer are nonseasonal breeders with the breeding peak in February. Although the earliest age at which a female reached sexual maturity was 11 months, the mean age was 23 ± 7 months. Mean age of first fawning was 32 ± 8 months. Mean gestation period was 259 ± 12 days (n = 82). Stags shed antlers mostly between March and July. Velvet hardens at 103 ± 27 days (n = 23), and velvet harvesting is best at 7-9 weeks when antler length is 25-30 cm. Sambar deer are suitable as a farm species in forest plantations and have a vast potential to uplift rural living standards.

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)

Do cupins have a function beyond being seed storage proteins? An updated working model for the growth and reproductive success of flax (Linum usitatissimum in a radio-contaminated environment

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Daša eGábrišová

2016-01-01

Full Text Available Plants continue to flourish around the site of the Chernobyl Nuclear Power Plant disaster. The ability of plants to transcend the radio-contaminated environment was not anticipated and is not well understood. The aim of this study was to evaluate the proteome of flax (Linum usitatissimum L. during seed filling by plants grown for a third generation near Chernobyl. For this purpose, seeds were harvested at 2, 4, and 6 weeks after flowering and at maturity, from plants grown in either non-radioactive or radio-contaminated experimental fields. Total proteins were extracted and the two-dimensional gel electrophoresis (2-DE patterns analyzed. This approach established paired abundance profiles for 130 2-DE spots, e.g., profiles for the same spot across seed filling in non-radioactive and radio-contaminated experimental fields. Based on Analysis of Variance (ANOVA followed by sequential Bonferroni correction, eight of the paired abundance profiles were discordant. Results from tandem mass spectrometry show that four 2-DE spots are discordant because they contain fragments of the cupin superfamily-proteins. Most of the fragments were derived from the N-terminal half of native cupins. Revisiting previously published data, it was found that cupin-fragments were also involved with discordance in paired abundance profiles of second generation flax seeds. Based on these observations we present an updated working model for the growth and reproductive success of flax in a radio-contaminated Chernobyl environment. This model suggests that the increased abundance of cupin fragments or isoforms and monomers contributes to the successful growth and reproduction of flax in a radio-contaminated environment.

Re-translocation of boron in broccoli and lupin during early reproductive growth

Energy Technology Data Exchange (ETDEWEB)

Marentes, E; Shelp, B J [Univ. of Guelph, Dept. of Horticultural Science, Guelph, ON (Canada); Vanderpool, R A [USDA, Human Nutrition Research Center, Agricultural Research Service, ND (United States); [Spiers, G.A. Univ. of Guelph, Dept. of Land Resource Science, Guelph, ON (Canada)

1997-06-01

The objective of the present study was to determine if boron (B) re-translocation depends on plant-B status and external-B supply. The stable {sup 10}B isotope was supplied to the root system of broccoli (Brassica oleracea var. italica Plenck cv. Commander) and lupin (Lupinus albus L. cv. Ultra) plants to provide a quantitative picture of B distribution during early reproductive development. Regardless of the B regime (i.e. continuous supply with luxury, sufficient or deficient B; transfer at influorescence emergence from either a luxury- or sufficient-B supply to a deficient one) and whether {sup 10}B was acquired before or during influorescence development, a significant proportion of the B recovered in broccoli florest and lupin fruit was {sup 10}B enriched. B acquired during inflorescence development was an important source of B for reproductive structures, but the relative importance of B acquired before and after inflorescence emergence appeared to be species dependent. The occurrence of B re-translocation was not dependent upon the induction of B deficiency. The concentrations of B in phloem exsudates (0.38 to 0.03 mM) were 4- to 23-fold those in xylem sap, and more similar to the concentrations in the reproductive structures (0.86 to 0.07 mM) than those in source leaves (2.4 to 0.19 mM). The decreasing acropetal gradient of tissue-B concentrations with luxury-B supply declined dramatically or was reversed in plants grown with sufficient or deficient B. The data are consistent with B being a phloem-mobile element, and suggest that newly acquired B is particularly important during the early reproductive growth of plants. (au) 36 refs.

Re-translocation of boron in broccoli and lupin during early reproductive growth

International Nuclear Information System (INIS)

Marentes, E.; Shelp, B.J.; Vanderpool, R.A.

1997-01-01

The objective of the present study was to determine if boron (B) re-translocation depends on plant-B status and external-B supply. The stable 10 B isotope was supplied to the root system of broccoli (Brassica oleracea var. italica Plenck cv. Commander) and lupin (Lupinus albus L. cv. Ultra) plants to provide a quantitative picture of B distribution during early reproductive development. Regardless of the B regime (i.e. continuous supply with luxury, sufficient or deficient B; transfer at influorescence emergence from either a luxury- or sufficient-B supply to a deficient one) and whether 10 B was acquired before or during influorescence development, a significant proportion of the B recovered in broccoli florest and lupin fruit was 10 B enriched. B acquired during inflorescence development was an important source of B for reproductive structures, but the relative importance of B acquired before and after inflorescence emergence appeared to be species dependent. The occurrence of B re-translocation was not dependent upon the induction of B deficiency. The concentrations of B in phloem exsudates (0.38 to 0.03 mM) were 4- to 23-fold those in xylem sap, and more similar to the concentrations in the reproductive structures (0.86 to 0.07 mM) than those in source leaves (2.4 to 0.19 mM). The decreasing acropetal gradient of tissue-B concentrations with luxury-B supply declined dramatically or was reversed in plants grown with sufficient or deficient B. The data are consistent with B being a phloem-mobile element, and suggest that newly acquired B is particularly important during the early reproductive growth of plants. (au) 36 refs

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

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

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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.

Effect of restricted feeding under rearing on reproduction, body condition and blood metabolites of rabbit does selected for growth rate

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C. Naturil-Alfonso

2017-12-01

Full Text Available Young rabbit females selected for growth rate can have nutritional needs which may not be met by the common practice of feed restriction during rearing in commercial rabbit production. The aim of this study was to analyse the effect of two different feeding programmes: restricted and ad libitum feeding, applied in young rabbit females for one month at the end of rearing, on reproductive performance, body condition and circulating metabolic hormones and metabolites in a rabbit line selected by growth rate in 3 consecutive reproductive cycles. Thus, twenty-four 16-week-old does were randomly assigned to a group in which the daily recommended nutrient intakes were satisfied (fed restricted: 130 g/day, n=13 or a group fed to satiety (ad libitum: 235.5 g/day, n=11 during one month. Then, all does were inseminated in 3 consecutive cycles using a 42-day reproductive cycle. Measurements of does’ body weight, perirenal fat thickness and plasma leptin, non-esterified-fatty-acids (NEFA, beta-hydroxybutyrate (BOHB and fructosamine were performed at artificial insemination (AI, parturition and weaning time in 3 consecutive cycles. Reproductive performance of does was evaluated based on fertility, litter size at parturition, prolificacy and productivity. Differences in body weight were found only in the 1st cycle, ad libitum fed females being heavier than restricted ones. Nevertheless, body weight variances disappeared in later cycles. No differences were found in perirenal fat thickness. Finally, in ad libitum fed females slight differences were found in plasma levels of NEFAs (452 vs. 258 μekv/L and 527 vs. 306 μekv/L for 1st and 2nd cycles and BOHB (0.26 vs. 0.03 mM for 2nd cycle, but disappeared in the 3rd reproductive cycle. Fertility, prolificacy and productivity was not significantly affected by the feeding programme. Nevertheless, total litter size showed to be higher in ad libitum fed females at second parturition (8.7 vs. 5.9 kits. Therefore

Mum, why do you keep on growing? Impacts of environmental variability on optimal growth and reproduction allocation strategies of annual plants.

Science.gov (United States)

De Lara, Michel

2006-05-01

In their 1990 paper Optimal reproductive efforts and the timing of reproduction of annual plants in randomly varying environments, Amir and Cohen considered stochastic environments consisting of i.i.d. sequences in an optimal allocation discrete-time model. We suppose here that the sequence of environmental factors is more generally described by a Markov chain. Moreover, we discuss the connection between the time interval of the discrete-time dynamic model and the ability of the plant to rebuild completely its vegetative body (from reserves). We formulate a stochastic optimization problem covering the so-called linear and logarithmic fitness (corresponding to variation within and between years), which yields optimal strategies. For "linear maximizers'', we analyse how optimal strategies depend upon the environmental variability type: constant, random stationary, random i.i.d., random monotonous. We provide general patterns in terms of targets and thresholds, including both determinate and indeterminate growth. We also provide a partial result on the comparison between ;"linear maximizers'' and "log maximizers''. Numerical simulations are provided, allowing to give a hint at the effect of different mathematical assumptions.

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

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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.

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.

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

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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.

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

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...

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....

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

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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.

[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.

Effect of Ppd-1 on the expression of flowering-time genes in vegetative and reproductive growth stages of wheat.

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Kitagawa, Satoshi; Shimada, Sanae; Murai, Koji

2012-01-01

The photoperiod sensitivity gene Ppd-1 influences the timing of flowering in temperate cereals such as wheat and barley. The effect of Ppd-1 on the expression of flowering-time genes was assessed by examining the expression levels of the vernalization genes VRN1 and VRN3/WFT and of two CONSTANS-like genes, WCO1 and TaHd1, during vegetative and reproductive growth stages. Two near-isogenic lines (NILs) were used: the first carried a photoperiod-insensitive allele of Ppd-1 (Ppd-1a-NIL), the other, a photoperiod-sensitive allele (Ppd-1b-NIL). We found that the expression pattern of VRN1 was similar in Ppd-1a-NIL and Ppd-1b-NIL plants, suggesting that VRN1 is not regulated by Ppd-1. Under long day conditions, VRN3/WFT showed similar expression patterns in Ppd-1a-NIL and Ppd-1b-NIL plants. However, expression differed greatly under short day conditions: VRN3/WFT expression was detected in Ppd-1a-NIL plants at the 5-leaf stage when they transited from vegetative to reproductive growth; very low expression was present in Ppd-1b-NIL throughout all growth stages. Thus, the Ppd-1b allele acts to down-regulate VRN3/WFT under short day conditions. WCO1 showed high levels of expression at the vegetative stage, which decreased during the phase transition and reproductive growth stages in both Ppd-1a-NIL and Ppd-1b-NIL plants under short day conditions. By contrast to WCO1, TaHd1 was up-regulated during the reproductive stage. The level of TaHd1 expression was much higher in Ppd-1a-NIL than the Ppd-1b-NIL plants, suggesting that the Ppd-1b allele down-regulates TaHd1 under short day conditions. The present study indicates that down-regulation of VRN3/WFT together with TaHd1 is the cause of late flowering in the Ppd-1b-NIL plants under short day conditions.

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.

Impaired reproduction and individual growth of the water flea Daphnia magna as consequence of exposure to the non-ester pyrethroid etofenprox.

Science.gov (United States)

Sancho, Encarna; Banegas, Sandra; Villarroel, María José; Ferrando, Dolores

2018-03-01

The effect of the pesticide etofenprox (0.76, 0.95, 1.18, 1.48, and 1.85 μg L -1 ) on survival, reproduction, and growth of Daphnia magna organisms was monitored using 21-day exposure tests. In order to test pesticide effects on D. magna, survival, length, mean total neonates per female, mean brood size, time to first reproduction, mean number broods per female, cumulative molting, and the population parameter intrinsic rate of natural increase (r) were used. Reproduction was seriously affected by etofenprox. Concentrations of etofenprox higher than 1.18 μg L -1 affected all the reproductive parameters analyzed as well as individual length. However, daphnids' survival after 21 days of pesticide exposure did not exhibited differences among experimental and control groups. The no observed effect concentration (NOEC), the lowest observed effect concentration (LOEC), and the maximum acceptable toxicant concentration (MATC) were calculated for the different parameters. A MATC estimation of 1.32 μg L -1 was calculated for mean brood size, mean number of broods per female, mean number of neonates per female, and the intrinsic rate of growth population. Etofenprox effect on the algae Nannochloris oculata was also evaluated. The selected etofenprox concentrations did not affect algal growth rate (μ) after 24 h; however, N. oculata exposed during 48 and 72 h to the highest etofenprox concentration showed a decreased in its population rate.

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.

The Effect of Latitudinal Variation on Shrimp Reproductive Strategies.

Directory of Open Access Journals (Sweden)

Madelon van de Kerk

Full Text Available 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.

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...

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...

Effects of functionalized fullerenes on bifenthrin and tribufos toxicity to Daphnia magna: Survival, reproduction, and growth rate.

Science.gov (United States)

Brausch, Kathryn A; Anderson, Todd A; Smith, Philip N; Maul, Jonathan D

2010-11-01

Incorporation of carbon nanomaterials into industrial and consumer products is increasing, yet their impact on aquatic ecosystems alone and in chemical mixtures is largely unknown. Carbon nanomaterials may be found in the aquatic environment as mixtures with pesticides because of their proposed use in agriculture as smart delivery systems and nanosensors. The interaction effects of a functionalized fullerene ([1,2-methanofullerene C₆₀]-61-carboxylic acid) (fC₆₀) at 52.8 µg/L and the hydrophobic pesticides bifenthrin and tribufos were examined. The test organism was Daphnia magna, and response variables included 48-h survival, reproduction (bifenthrin, 70-d; tribufos, 21-d), and 10-d growth. Both pesticides reduced D. magna survival and reproduction (p bifenthrin acute toxicity but did not significantly affect chronic endpoints or growth (p > 0.05). Median lethal concentrations (LC50s), median inhibition concentrations (IC50s) for days surviving, and IC50s for reproduction were 0.86, 0.55, and 0.49 µg/L for bifenthrin; 0.22, 0.39, and 0.77 µg/L for fC₆₀-bifenthrin mix; 6.63, 9.89, and 5.79 µg/L for tribufos; and 9.17, 8.17, and 6.59 µg/L for fC₆₀-tribufos mix. Mixtures did not affect instantaneous growth rate (p > 0.05). These results suggest that fC₆₀ had little effect on pesticide chronic toxicity but influenced acute toxicity. Given the widespread application of nanotechnology, the influence of nanomaterials on environmental contaminants is an important consideration. Thus, our results may be useful in the development and use of nanotechnology in agricultural practices. © 2010 SETAC.

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

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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.

The Mahabharata and reproductive endocrinology

OpenAIRE

Kalra, Bharti; Baruah, Manash P.; Kalra, Sanjay

2016-01-01

This communication approaches the Mahabharata through the prism of reproductive endocrinology. Descriptions of episodes related to reproduction are listed here, to provide fodder for the endocrinologically minded brain. The cases described here are perhaps, the first documented observations of fetal orgasm, pseudocyesis and assisted reproductive technology, including assisted insemination by donor, induction of ovulation, and in vitro fertilization as well as precocious growth and intersex. W...

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

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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.

The dynamics of reproductive rate, offspring survivorship and growth in the lined seahorse, Hippocampus erectus Perry, 1810

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Lin, Qiang; Li, Gang; Qin, Geng; Lin, Junda; Huang, Liangmin; Sun, Hushan; Feng, Peiyong

2012-01-01

Summary Seahorses are the vertebrate group with the embryonic development occurring within a special pouch in males. To understand the reproductive efficiency of the lined seahorse, Hippocampus erectus Perry, 1810 under controlled breeding experiments, we investigated the dynamics of reproductive rate, offspring survivorship and growth over births by the same male seahorses. The mean brood size of the 1-year old pairs in the 1st birth was 85.4±56.9 per brood, which was significantly smaller than that in the 6th birth (465.9±136.4 per brood) (Pseahorses H. erectus increased with the brood pouch development. PMID:23213429

Modelling Growth and Partitioning of Annual Above-Ground Vegetative and Reproductive Biomass of Grapevine

Science.gov (United States)

Meggio, Franco; Vendrame, Nadia; Maniero, Giovanni; Pitacco, Andrea

2014-05-01

In the current climate change scenarios, both agriculture and forestry inherently may act as carbon sinks and consequently can play a key role in limiting global warming. An urgent need exists to understand which land uses and land resource types have the greatest potential to mitigate greenhouse gas (GHG) emissions contributing to global change. A common believe is that agricultural fields cannot be net carbon sinks due to many technical inputs and repeated disturbances of upper soil layers that all contribute to a substantial loss both of the old and newly-synthesized organic matter. Perennial tree crops (vineyards and orchards), however, can behave differently: they grow a permanent woody structure, stand undisturbed in the same field for decades, originate a woody pruning debris, and are often grass-covered. In this context, reliable methods for quantifying and modelling emissions and carbon sequestration are required. Carbon stock changes are calculated by multiplying the difference in oven dry weight of biomass increments and losses with the appropriate carbon fraction. These data are relatively scant, and more information is needed on vineyard management practices and how they impact vineyard C sequestration and GHG emissions in order to generate an accurate vineyard GHG footprint. During the last decades, research efforts have been made for estimating the vineyard carbon budget and its allocation pattern since it is crucial to better understand how grapevines control the distribution of acquired resources in response to variation in environmental growth conditions and agronomic practices. The objective of the present study was to model and compare the dynamics of current year's above-ground biomass among four grapevine varieties. Trials were carried out over three growing seasons in field conditions. The non-linear extra-sums-of-squares method demonstrated to be a feasible way of growth models comparison to statistically assess significant differences among

The role of brain peptides in the reproduction of blue gourami males (Trichogaster trichopterus).

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Levy, Gal; Degani, Gad

2013-10-01

In all vertebrates, reproduction and growth are closely linked and both are controlled by complex hormonal interactions at the brain-pituitary level. In this study, we focused on the reciprocal interactions between brain peptides that regulate growth and reproductive functions in a teleostei fish (blue gourami Trichogaster trichopterus). An increase in gonadotropin-releasing hormone 1 (GnRH1) gene expression was detected during ontogeny, and this peptide increased growth hormone (GH) and β follicle-stimulating hormone (βFSH) gene expression in pituitary cell culture. However, although no change in gonadotropin-releasing hormone 2 (GnRH2) gene expression during the reproductive cycle or sexual behavior was detected, a stimulatory effect of this peptide on β gonadotropins (βGtH) gene expression was observed. In addition, pituitary adenylate cyclase-activating polypeptide 38 (PACAP-38) inhibited GnRH-analog-induced βFSH gene expression, and co-treatment of cells with GnRH-analog and PACAP-38 inhibited GnRH-analog-stimulatory and PACAP-38-inhibitory effects on GH gene expression. These findings together with previous studies were used to create a model summarizing the mechanism of brain peptides (GnRH, PACAP and its related peptide) and the relationship to reproduction and growth through pituitary hormone gene expression during ontogenesis and reproductive stages in blue gourami. © 2013 Wiley Periodicals, Inc.

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…

DNA alterations and effects on growth and reproduction in Daphnia magna during chronic exposure to gamma radiation over three successive generations

International Nuclear Information System (INIS)

Parisot, Florian; Bourdineaud, Jean-Paul; Plaire, Delphine; Adam-Guillermin, Christelle; Alonzo, Frédéric

2015-01-01

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 −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 −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 −1 in F0 and by reductions of 5 and 13% in growth rate, respectively, at 4.70 and 35.4 mGy h −1 in F2. Reproduction was affected by a reduction of 19% in 21 day-fecundity at 35.4 mGy h −1 in F0 and by a delay of 1.9 days in brood release as low as 0.070 mGy h −1 in F2. In parallel, DNA alterations became significant at decreasing dose rates over the course of F0 (from 4.70 mGy h −1 at hatching to 0.007 mGy h −1 after ∼21 days) and from F0 to F2 (0.070 mGy h −1 at hatching to 0.007 mGy h −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 −1 and DNA alterations significant at highest dose rates only. The study improved our understanding of

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

Seasonal timing in a warming world : plasticity of seasonal timing of growth and reproduction

OpenAIRE

Salis, L.

2015-01-01

In seasonal environments the timing of various biological processes is crucial for growth, survival and reproductive success of an individual. Nowadays, rapid large-scale climate change is altering species’ seasonal timing (phenology) in many eco¬systems. In this thesis Lucia Salis focuses on the study of seasonal timing in the food chain of the oak-winter moth-great tit. As temperature increased over the last decades, both phenologies of the host plant, the oak, and the herbivorous insect, t...

Halofuginone suppresses growth of human uterine leiomyoma cells in a mouse xenograft model.

Science.gov (United States)

Koohestani, Faezeh; Qiang, Wenan; MacNeill, Amy L; Druschitz, Stacy A; Serna, Vanida A; Adur, Malavika; Kurita, Takeshi; Nowak, Romana A

2016-07-01

Does halofuginone (HF) inhibit the growth of human uterine leiomyoma cells in a mouse xenograft model? HF suppresses the growth of human uterine leiomyoma cells in a mouse xenograft model through inhibiting cell proliferation and inducing apoptosis. Uterine leiomyomas are the most common benign tumors of the female reproductive tract. HF can suppress the growth of human uterine leiomyoma cells in vitro. The mouse xenograft model reflects the characteristics of human leiomyomas. Primary leiomyoma smooth muscle cells from eight patients were xenografted under the renal capsule of adult, ovariectomized NOD-scid IL2Rγ(null) mice (NSG). Mice were treated with two different doses of HF or vehicle for 4 weeks with six to eight mice per group. Mouse body weight measurements and immunohistochemical analysis of body organs were carried out to assess the safety of HF treatment. Xenografted tumors were measured and analyzed for cellular and molecular changes induced by HF. Ovarian steroid hormone receptors were evaluated for possible modulation by HF. Treatment of mice carrying human UL xenografts with HF at 0.25 or 0.50 mg/kg body weight for 4 weeks resulted in a 35-40% (P leiomyoma cells in an in vivo model, HF was administered to mice whose tolerance and metabolism of the drug may differ from that in humans. Also, the longer term effects of HF treatment are yet unclear. The results of this study showing the effectiveness of HF in reducing UL tumor growth by interfering with the main cellular processes regulating cell proliferation and apoptosis are in agreement with previous studies on the effects of HF on other fibrotic diseases. HF can be considered as a candidate for reducing the size of leiomyomas, particularly prior to surgery. This project was funded by NIH PO1HD057877 and R01 HD064402. Authors report no competing interests. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights

Resource allocation to reproduction in animals.

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Kooijman, Sebastiaan A L M; Lika, Konstadia

2014-11-01

The standard Dynamic Energy Budget (DEB) model assumes that a fraction κ of mobilised reserve is allocated to somatic maintenance plus growth, while the rest is allocated to maturity maintenance plus maturation (in embryos and juveniles) or reproduction (in adults). All DEB parameters have been estimated for 276 animal species from most large phyla and all chordate classes. The goodness of fit is generally excellent. We compared the estimated values of κ with those that would maximise reproduction in fully grown adults with abundant food. Only 13% of these species show a reproduction rate close to the maximum possible (assuming that κ can be controlled), another 4% have κ lower than the optimal value, and 83% have κ higher than the optimal value. Strong empirical support hence exists for the conclusion that reproduction is generally not maximised. We also compared the parameters of the wild chicken with those of races selected for meat and egg production and found that the latter indeed maximise reproduction in terms of κ, while surface-specific assimilation was not affected by selection. We suggest that small values of κ relate to the down-regulation of maximum body size, and large values to the down-regulation of reproduction. We briefly discuss the ecological context for these findings. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical Society.

Color reproduction system based on color appearance model and gamut mapping

Science.gov (United States)

Cheng, Fang-Hsuan; Yang, Chih-Yuan

2000-06-01

By the progress of computer, computer peripherals such as color monitor and printer are often used to generate color image. However, cross media color reproduction by human perception is usually different. Basically, the influence factors are device calibration and characterization, viewing condition, device gamut and human psychology. In this thesis, a color reproduction system based on color appearance model and gamut mapping is proposed. It consists of four parts; device characterization, color management technique, color appearance model and gamut mapping.

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

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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

The Influence of Thermic Plastic Films on Vegetative and Reproductive Growth of Iceberg Lettuce 'Dublin'

OpenAIRE

Wael M. Semida; P. Hadley; W. Sobeih; N. A. El-Sawah; M. A. S. Barakat

2013-01-01

Photoselective plastic films with thermic properties are now available so that greenhouses clad with such plastics exhibit a higher degree of “Greenhouse Effect” with a consequent increase in night time temperature. In this study, we investigate the potential benefits of a range of thermic plastic films used as greenhouse cover materials on the vegetative and reproductive growth and development of Iceberg lettuce (Lactuca sativa L). Transplants were grown under thermic fi...

Integrative Control of Energy Balance and Reproduction in Females

OpenAIRE

Garcia-Garcia, R. M.

2012-01-01

There is a strong association between nutrition and reproduction. Chronic dietary energy deficits as well as energy surpluses can impair reproductive capacity. Metabolic status impacts reproductive function at systemic level, modulating the hypothalamic GnRH neuronal network and/or the pituitary gonadotropin secretion through several hormones and neuropeptides, and at the ovarian level, acting through the regulation of follicle growth and steroidogenesis by means of the growth hormone-IGF-ins...

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

Ionizing radiation promotes protozoan reproduction

International Nuclear Information System (INIS)

Luckey, T.D.

1986-01-01

This experiment was performed to determine whether ionizing radiation is essential for maximum growth rate in a ciliated protozoan. When extraneous ionizing radiation was reduced to 0.15 mrad/day, the reproduction rate of Tetrahymena pyriformis was significantly less (P less than 0.01) than it was at near ambient levels, 0.5 or 1.8 mrad/day. Significantly higher growth rates (P less than 0.01) were obtained when chronic radiation was increased. The data suggest that ionizing radiation is essential for optimum reproduction rate in this organism

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

The dynamics of temperature and light on the growth of phytoplankton.

Science.gov (United States)

Chen, Ming; Fan, Meng; Liu, Rui; Wang, Xiaoyu; Yuan, Xing; Zhu, Huaiping

2015-11-21

Motivated by some lab and field observations of the hump shaped effects of water temperature and light on the growth of phytoplankton, a bottom-up nutrient phytoplankton model, which incorporates the combined effects of temperature and light, is proposed and analyzed to explore the dynamics of phytoplankton bloom. The population growth model reasonably captures such observed dynamics qualitatively. An ecological reproductive index is defined to characterize the growth of the phytoplankton which also allows a comprehensive analysis of the role of temperature and light on the growth and reproductive characteristics of phytoplankton in general. The model provides a framework to study the mechanisms of phytoplankton dynamics in shallow lake and may even be employed to study the controlled phytoplankton bloom. Copyright © 2015 Elsevier Ltd. All rights reserved.

The amazing growth of the early church

Directory of Open Access Journals (Sweden)

Wim A. Dreyer

2012-11-01

Full Text Available The church grew rapidly during the first centuries. The question is: Why? Generations of scholars approached this question from different perspectives and with different methods. Historical research, analysis of early Christian texts and theological reflection were the most common methods used to shed light on the growth of the church. In this contribution five different models of growth were discussed, using the approach of A.M. Schor as a point of departure. These models of church growth were put under the headings of an apostolic mission model, values reproduction model, social reaction model, network model with an institutional model added.

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.

Impaired reproduction after exposure to ADHD drugs

DEFF Research Database (Denmark)

Danborg, Pia Brandt; Simonsen, Anders Lykkemark; Gøtzsche, Peter C

2017-01-01

BACKGROUND: Few studies have reported on long-term harms caused by ADHD drugs but they are known to impair growth. OBJECTIVE: To assess whether ADHD drugs impair reproduction in mammals. METHODS: Systematic review of reproduction in studies of animals treated with ADHD drugs. DATA SOURCES: Pub....... CONCLUSION: ADHD drugs impair the reproduction in animals....

A Dynamic Model of Cultural Reproduction

DEFF Research Database (Denmark)

Jæger, Mads Meier; Breen, Richard

2016-01-01

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...... 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...... 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....

Fisheries-induced evolution in growth, maturation and reproductive investment of the sexually dimorphic North Sea plaice (Pleuronectes platessa L.)

NARCIS (Netherlands)

van Walraven, L.; Mollet, F. M.; van Damme, C. J. G.; Rijnsdorp, A. D.

2010-01-01

Changes in the onset of sexual maturation, reproductive investment and growth of North Sea plaice are studied between three periods: 1900s, 1980s and 2000s. Probabilistic maturation reaction norms of both males and females, describing the probability of becoming mature conditional on age and size,

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,

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.

Modelling spatio-temporal variability of Mytilus edulis (L.) growth by forcing a dynamic energy budget model with satellite-derived environmental data

Science.gov (United States)

Thomas, Yoann; Mazurié, Joseph; Alunno-Bruscia, Marianne; Bacher, Cédric; Bouget, Jean-François; Gohin, Francis; Pouvreau, Stéphane; Struski, Caroline

2011-11-01

In order to assess the potential of various marine ecosystems for shellfish aquaculture and to evaluate their carrying capacities, there is a need to clarify the response of exploited species to environmental variations using robust ecophysiological models and available environmental data. For a large range of applications and comparison purposes, a non-specific approach based on 'generic' individual growth models offers many advantages. In this context, we simulated the response of blue mussel ( Mytilus edulis L.) to the spatio-temporal fluctuations of the environment in Mont Saint-Michel Bay (North Brittany) by forcing a generic growth model based on Dynamic Energy Budgets with satellite-derived environmental data (i.e. temperature and food). After a calibration step based on data from mussel growth surveys, the model was applied over nine years on a large area covering the entire bay. These simulations provide an evaluation of the spatio-temporal variability in mussel growth and also show the ability of the DEB model to integrate satellite-derived data and to predict spatial and temporal growth variability of mussels. Observed seasonal, inter-annual and spatial growth variations are well simulated. The large-scale application highlights the strong link between food and mussel growth. The methodology described in this study may be considered as a suitable approach to account for environmental effects (food and temperature variations) on physiological responses (growth and reproduction) of filter feeders in varying environments. Such physiological responses may then be useful for evaluating the suitability of coastal ecosystems for shellfish aquaculture.

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.

Toward the definition of a carbon budget model: seasonal variation and temperature effect on respiration rate of vegetative and reproductive organs of pistachio trees (Pistacia vera).

Science.gov (United States)

Marra, Francesco P; Barone, Ettore; La Mantia, Michele; Caruso, Tiziano

2009-09-01

This study, as a preliminary step toward the definition of a carbon budget model for pistachio trees (Pistacia vera L.), aimed at estimating and evaluating the dynamics of respiration of vegetative and reproductive organs of pistachio tree. Trials were performed in 2005 in a commercial orchard located in Sicily (370 m a.s.l.) on five bearing 20-year-old pistachio trees of cv. Bianca grafted onto Pistachio terebinthus L. Growth analyses and respiration measurements were done on vegetative (leaf) and reproductive (infructescence) organs during the entire growing season (April-September) at biweekly intervals. Results suggested that the respiration rates of pistachio reproductive and vegetative organs were related to their developmental stage. Both for leaf and for infructescence, the highest values were observed during the earlier stages of growth corresponding to the phases of most intense organ growth. The sensitivity of respiration activity to temperature changes, measured by Q(10), showed an increase throughout the transition from immature to mature leaves, as well as during fruit development. The data collected were also used to estimate the seasonal carbon loss by respiration activity for a single leaf and a single infructescence. The amount of carbon lost by respiration was affected by short-term temperature patterns, organ developmental stage and tissue function.

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.

The growth of vegetative and reproductive structures (leaves and silks) respond similarly to hydraulic cues in maize.

Science.gov (United States)

Turc, Olivier; Bouteillé, Marie; Fuad-Hassan, Avan; Welcker, Claude; Tardieu, François

2016-10-01

The elongation of styles and stigma (silks) of maize (Zea mays) flowers is rapid (1-3 mm h(-1) ), occurs over a short period and plays a pivotal role in reproductive success in adverse environments. Silk elongation rate was measured using displacement transducers in 350 plants of eight genotypes during eight experiments with varying evaporative demand and soil water status. Measured time courses revealed that silk elongation rate closely followed changes in soil water status and evaporative demand, with day-night alternations similar to those in leaves. Day-night alternations were steeper with high than with low plant transpiration rate, manipulated via evaporative demand or by covering part of the leaf area. Half times of changes in silk elongation rate upon changes in evaporative demand or soil water status were 10-30 min, similar to those in leaves. The sensitivity of silk elongation rate to xylem water potential was genetically linked to that of leaf elongation rate. Lines greatly differed for these sensitivities. These results are consistent with a common hydraulic control of expansive growth in vegetative and reproductive structures upon changes in environmental conditions via a close connection with the xylem water potential. They have important implications for breeding, modelling and phenotyping. © 2016 INRA. New Phytologist © 2016 New Phytologist Trust.

Progeny reproduction

International Nuclear Information System (INIS)

Mashneva, N.I.

1984-01-01

Studies on clarification of importance of different harmful factors of radiation and chemical nature on the function of progeny reproduction, growth and development are presented. Intake of radionuclides to organism, of white mices and rats in concentrations corresponding to 10 6 PCsub(s) ( 90 Sr, 210 Po, 210 Pb and other) is shown to result in 100% sterility of females, 10 5 -10 4 PCsub(s) concentrations cause damaging effect of different degrees of expression at later stages of effect. Smaller contents of radionuclides (10 3 -10 2 PCsub(s)) did not result in noticeable changes in reproductivity of animals. Similar regularities were observed under effect of different concentrations of chemical agent. Some peculiarities of animal physiology should be taken into account to obtain data of estimation of damaging effect of harmful factors on reproduction function

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.

Reproductive rights approach to reproductive health in developing countries

Directory of Open Access Journals (Sweden)

Vijayan K. Pillai

2011-12-01

Full Text Available Research on reproductive health in developing countries focuses mostly on the role of economic development on various components of reproductive health. Cross-sectional and empirical research studies in particular on the effects of non-economic factors such as reproductive rights remain few and far between.This study investigates the influence of two components of an empowerment strategy, gender equality, and reproductive rights on women's reproductive health in developing countries. The empowerment strategy for improving reproductive health is theoretically situated on a number of background factors such as economic and social development.Cross-national socioeconomic and demographic data from a number of international organizations on 142 developing countries are used to test a model of reproductive rights and reproductive health.The findings suggest that both economic and democratic development have significant positive effects on levels of gender equality. The level of social development plays a prominent role in promoting reproductive rights. It is found that reproductive rights channel the influences of social structural factors and gender equality on reproductive health.

Reproductive rights approach to reproductive health in developing countries.

Science.gov (United States)

Pillai, Vijayan K; Gupta, Rashmi

2011-01-01

Research on reproductive health in developing countries focuses mostly on the role of economic development on various components of reproductive health. Cross-sectional and empirical research studies in particular on the effects of non-economic factors such as reproductive rights remain few and far between. This study investigates the influence of two components of an empowerment strategy, gender equality, and reproductive rights on women's reproductive health in developing countries. The empowerment strategy for improving reproductive health is theoretically situated on a number of background factors such as economic and social development. Cross-national socioeconomic and demographic data from a number of international organizations on 142 developing countries are used to test a model of reproductive rights and reproductive health. The findings suggest that both economic and democratic development have significant positive effects on levels of gender equality. The level of social development plays a prominent role in promoting reproductive rights. It is found that reproductive rights channel the influences of social structural factors and gender equality on reproductive health.

Changes in oxidative stress parameters in relation to age, growth and reproduction in the short-lived catarina scallop Argopecten ventricosus reared in its natural environment.

Science.gov (United States)

Guerra, C; Zenteno-Savín, T; Maeda-Martínez, A N; Philipp, E E R; Abele, D

2012-08-01

Increase in oxidative damage and decrease in cellular maintenance is often associated with aging, but, in marine ectotherms, both processes are also strongly influenced by somatic growth, maturation and reproduction. In this study, we used a single cohort of the short-lived catarina scallop Argopecten ventricosus, to investigate the effects of somatic growth, reproduction and aging on oxidative damage parameters (protein carbonyls, TBARS and lipofuscin) and cellular maintenance mechanisms (antioxidant activity and apoptosis) in scallops, caged in their natural environment. The concentrations of protein carbonyls and TBARS increased steeply during the early period of fast growth and during reproduction in one-year-old scallops. However, oxidative damage was transient, and apoptotic cell death played a pivotal role in eliminating damage in gill, mantle and muscle tissues of young scallops. Animals were able to reproduce again in the second year, but the reduced intensity of apoptosis impaired subsequent removal of damaged cells. In late survivors low antioxidant capacity and apoptotic activity together with a fast accumulation of the age pigment lipofuscin was observed. Rates of oxygen consumption and oxidative stress markers were strongly dependent on somatic growth and reproductive state but not on temperature. Compared to longer-lived bivalves, A. ventricosus seems more susceptible to oxidative stress with higher tissue-specific protein carbonyl levels and fast accumulation of lipofuscin in animals surviving the second spawning. Superoxide dismutase activity and apoptotic cell death intensity were however higher in this short-lived scallop than in longer-lived bivalves. The life strategy of this short-lived and intensely predated scallop supports rapid somatic growth and fitness as well as early maturation at young age at the cost of fast cellular degradation in second year scallops. Copyright © 2012 Elsevier Inc. All rights reserved.

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.

Mycorrhizal symbiosis increases growth, reproduction and recruitment of Abutilon theophrasti Medic. in the field.

Science.gov (United States)

Stanley, Margot R; Koide, Roger T; Shumway, Durland L

1993-05-01

We examined in the field the effect of the vesicular-arbuscular (VA) mycorhizal symbiosis on the reproductive success of Abutilon theophrasti Medic., an early successional annual member of the Malvaceae. Mycorrhizal infection greatly enhanced vegetative growth, and flower, fruit and seed production, resulting in significantly greater recruitment the following year. In addition, the seeds produced by mycorrhizal plants were significantly larger and contained significantly more phosphorus than seeds from non-mycorrhizal plants, an effect which may improve offspring vigor. Infection by mycorrhizal fungi may thus contribute to the overall fitness of a host plant and strongly influence long-term plant population dynamics.

Changing reproductive effort within a semelparous reproductive episode.

Science.gov (United States)

Hughes, P William; Simons, Andrew M

2014-08-01

• Life-history theory predicts a trade-off between current and future reproduction for iteroparous organisms-as individuals age, the expected value of future reproduction declines, and thus reproductive effort is expected to be higher in later clutches than in earlier. In contrast, models explaining the evolution of semelparity treat semelparous reproduction as instantaneous, with no scope for intraindividual variation. However, semelparous reproduction is also extended, but over shorter time scales; whether there are similar age- or stage-specific changes in reproductive effort within a semelparous episode is unclear. In this study, we assessed whether semelparous individuals increase reproductive effort as residual reproductive value declines by comparing the reproductive phenotype of flowers at five different floral positions along a main inflorescence.• Using the herbaceous monocarp Lobelia inflata, we conducted a longitudinal study of 409 individuals including both laboratory and field populations over three seasons. We recorded six reproductive traits-including the length of three phenological intervals as well as fruit size, seed size, and seed number-for all plants across floral positions produced throughout the reproductive episode.• We found that while the rate of flower initiation did not change, flowers at distal (late) floral positions developed more quickly and contained larger seed than flowers at basal (early) floral positions did.• Our results were consistent with the hypothesis that, like iteroparous organisms, L. inflata increases reproductive effort in response to low residual reproductive value. © 2014 Botanical Society of America, Inc.

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.

Coordination of size-control, reproduction and generational memory in freshwater planarians

Science.gov (United States)

Yang, Xingbo; Kaj, Kelson J.; Schwab, David J.; Collins, Eva-Maria S.

2017-06-01

Uncovering the mechanisms that control size, growth, and division rates of organisms reproducing through binary division means understanding basic principles of their life cycle. Recent work has focused on how division rates are regulated in bacteria and yeast, but this question has not yet been addressed in more complex, multicellular organisms. We have, over the course of several years, assembled a unique large-scale data set on the growth and asexual reproduction of two freshwater planarian species, Dugesia japonica and Girardia tigrina, which reproduce by transverse fission and succeeding regeneration of head and tail pieces into new planarians. We show that generation-dependent memory effects in planarian reproduction need to be taken into account to accurately capture the experimental data. To achieve this, we developed a new additive model that mixes multiple size control strategies based on planarian size, growth, and time between divisions. Our model quantifies the proportions of each strategy in the mixed dynamics, revealing the ability of the two planarian species to utilize different strategies in a coordinated manner for size control. Additionally, we found that head and tail offspring of both species employ different mechanisms to monitor and trigger their reproduction cycles. Thus, we find a diversity of strategies not only between species but between heads and tails within species. Our additive model provides two advantages over existing 2D models that fit a multivariable splitting rate function to the data for size control: firstly, it can be fit to relatively small data sets and can thus be applied to systems where available data is limited. Secondly, it enables new biological insights because it explicitly shows the contributions of different size control strategies for each offspring type.

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.

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

Directory of Open Access Journals (Sweden)

G Curtis

Full Text Available 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.

Reproduction Symposium: developmental programming of reproductive and metabolic health.

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Padmanabhan, V; Veiga-Lopez, A

2014-08-01

Inappropriate programming of the reproductive system by developmental exposure to excess steroid hormones is of concern. Sheep are well suited for investigating developmental origin of reproductive and metabolic disorders. The developmental time line of female sheep (approximately 5 mo gestation and approximately 7 mo to puberty) is ideal for conducting sequential studies of the progression of metabolic and/or reproductive disruption from the developmental insult to manifestation of adult consequences. Major benefits of using sheep include knowledge of established critical periods to target adult defects, a rich understanding of reproductive neuroendocrine regulation, availability of noninvasive approaches to monitor follicular dynamics, established surgical approaches to obtain hypophyseal portal blood for measurement of hypothalamic hormones, and the ability to perform studies in natural setting thereby keeping behavioral interactions intact. Of importance is the ability to chronically instrument fetus and mother for determining early endocrine perturbations. Prenatal exposure of the female to excess testosterone (T) leads to an array of adult reproductive disorders that include LH excess, functional hyperandrogenism, neuroendocrine defects, multifollicular ovarian morphology, and corpus luteum dysfunction culminating in early reproductive failure. At the neuroendocrine level, all 3 feedback systems are compromised. At the pituitary level, gonadotrope (LH secretion) sensitivity to GnRH is increased. Multifollicular ovarian morphology stems from persistence of follicles as well as enhanced follicular recruitment. These defects culminate in progressive loss of cyclicity and reduced fecundity. Prenatal T excess also leads to fetal growth retardation, an early marker of adult reproductive and metabolic diseases, insulin resistance, hypertension, and behavioral deficits. Collectively, the reproductive and metabolic deficits of prenatal T-treated sheep provide proof of

Is bigger better? The relationship between size and reproduction in female Asian elephants.

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Crawley, J A H; Mumby, H S; Chapman, S N; Lahdenperä, M; Mar, K U; Htut, W; Thura Soe, A; Aung, H H; Lummaa, V

2017-10-01

The limited availability of resources is predicted to impose trade-offs between growth, reproduction and self-maintenance in animals. However, although some studies have shown that early reproduction suppresses growth, reproduction positively correlates with size in others. We use detailed records from a large population of semi-captive elephants in Myanmar to assess the relationships between size (height and weight), reproduction and survival in female Asian elephants, a species characterized by slow, costly life history. Although female height gain during the growth period overlapped little with reproductive onset in the population, there was large variation in age at first reproduction and only 81% of final weight had been reached by peak age of reproduction at the population level (19 years). Those females beginning reproduction early tended to be taller and lighter later in life, although these trends were not significant. We found that taller females were more likely to have reproduced by a given age, but such effects diminished with age, suggesting there may be a size threshold to reproduction which is especially important in young females. Because size was not linked with female survival during reproductive ages, the diminishing effect of height on reproduction with age is unlikely to be due to biased survival of larger females. We conclude that although reproduction may not always impose significant costs on growth, height may be a limiting factor to reproduction in young female Asian elephants, which could have important implications considering their birth rates are low and peak reproduction is young - 19 years in this population. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Nonsteroidal Anti-inflammatory Drugs (NSAIDS) Inhibit the Growth and Reproduction of Chaetomium globosum and Other Fungi Associated with Water-Damaged Buildings.

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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.

Urban tree growth modeling

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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...

Gap junction connexins in female reproductive organs: implications for women's reproductive health.

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Winterhager, Elke; Kidder, Gerald M

2015-01-01

Connexins comprise a family of ~20 proteins that form intercellular membrane channels (gap junction channels) providing a direct route for metabolites and signalling molecules to pass between cells. This review provides a critical analysis of the evidence for essential roles of individual connexins in female reproductive function, highlighting implications for women's reproductive health. No systematic review has been carried out. Published literature from the past 35 years was surveyed for research related to connexin involvement in development and function of the female reproductive system. Because of the demonstrated utility of genetic manipulation for elucidating connexin functions in various organs, much of the cited information comes from research with genetically modified mice. In some cases, a distinction is drawn between connexin functions clearly related to the formation of gap junction channels and those possibly linked to non-channel roles. Based on work with mice, several connexins are known to be required for female reproductive functions. Loss of connexin43 (CX43) causes an oocyte deficiency, and follicles lacking or expressing less CX43 in granulosa cells exhibit reduced growth, impairing fertility. CX43 is also expressed in human cumulus cells and, in the context of IVF, has been correlated with pregnancy outcome, suggesting that this connexin may be a determinant of oocyte and embryo quality in women. Loss of CX37, which exclusively connects oocytes with granulosa cells in the mouse, caused oocytes to cease growing without acquiring meiotic competence. Blocking of CX26 channels in the uterine epithelium disrupted implantation whereas loss or reduction of CX43 expression in the uterine stroma impaired decidualization and vascularization in mouse and human. Several connexins are important in placentation and, in the human, CX43 is a key regulator of the fusogenic pathway from the cytotrophoblast to the syncytiotrophoblast, ensuring placental growth

Specificity of induced defenses, growth, and reproduction in lima bean (Phaseolus lunatus) in response to multispecies herbivory.

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Moreira, Xoaquín; Abdala-Roberts, Luis; Hernández-Cumplido, Johnattan; Cuny, Maximilien A C; Glauser, Gaetan; Benrey, Betty

2015-08-01

• Following herbivore attack, plants can either reduce damage by inducing defenses or mitigate herbivory effects through compensatory growth and reproduction. It is increasingly recognized that such induced defenses in plants are herbivore-specific, but less is known about the specificity of compensatory responses. Damage by multiple herbivores may also lead to synergistic effects on induction and plant fitness that differ from those caused by a single herbivore species. Although largely unstudied, the order of arrival and damage by different herbivore species might also play an important role in the impacts of herbivory on plants.• We investigated the specificity of defense induction (phenolics) and effects on growth (number of stems and leaves) and reproduction (number of seeds, seed mass, and germination rate) from feeding by two generalist leaf-chewing herbivores (Spodoptera eridania and Diabrotica balteata) on Phaseolus lunatus plants and evaluated whether simultaneous attack by both herbivores and their order of arrival influenced such dynamics.• Herbivory increased levels of leaf phenolics, but such effects were not herbivore-specific. In contrast, herbivory enhanced seed germination in an herbivore-specific manner. For all variables measured, the combined effects of both herbivore species did not differ from their individual effects. Finally, the order of herbivore arrival did not influence defense induction, plant growth, or seed number but did influence seed mass and germination.• Overall, this study highlights novel aspects of the specificity of plant responses induced by damage from multiple species of herbivores and uniquely associates such effects with plant lifetime fitness. © 2015 Botanical Society of America, Inc.

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

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Goshe, Lisa R.; Coggins, Lewis; Shaver, Donna J.; Higgins, Ben; Landry, Andre M.; Bailey, Rhonda

2017-01-01

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. PMID:28333937

Obligatory Effort [Hishtadlut] as an Explanatory Model: A Critique of Reproductive Choice and Control.

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Teman, Elly; Ivry, Tsipy; Goren, Heela

2016-06-01

Studies on reproductive technologies often examine women's reproductive lives in terms of choice and control. Drawing on 48 accounts of procreative experiences of religiously devout Jewish women in Israel and the US, we examine their attitudes, understandings and experiences of pregnancy, reproductive technologies and prenatal testing. We suggest that the concept of hishtadlut-"obligatory effort"-works as an explanatory model that organizes Haredi women's reproductive careers and their negotiations of reproductive technologies. As an elastic category with negotiable and dynamic boundaries, hishtadlut gives ultra-orthodox Jewish women room for effort without the assumption of control; it allows them to exercise discretion in relation to medical issues without framing their efforts in terms of individual choice. Haredi women hold themselves responsible for making their obligatory effort and not for pregnancy outcomes. We suggest that an alternative paradigm to autonomous choice and control emerges from cosmological orders where reproductive duties constitute "obligatory choices."

Exploiting rRNA operon copy number to investigate bacterial reproductive strategies.

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Roller, Benjamin R K; Stoddard, Steven F; Schmidt, Thomas M

2016-09-12

The potential for rapid reproduction is a hallmark of microbial life, but microbes in nature must also survive and compete when growth is constrained by resource availability. Successful reproduction requires different strategies when resources are scarce and when they are abundant 1,2 , but a systematic framework for predicting these reproductive strategies in bacteria has not been available. Here, we show that the number of ribosomal RNA operons (rrn) in bacterial genomes predicts two important components of reproduction-growth rate and growth efficiency-which are favoured under contrasting regimes of resource availability 3,4 . We find that the maximum reproductive rate of bacteria doubles with a doubling of rrn copy number, and the efficiency of carbon use is inversely related to maximal growth rate and rrn copy number. We also identify a feasible explanation for these patterns: the rate and yield of protein synthesis mirror the overall pattern in maximum growth rate and growth efficiency. Furthermore, comparative analysis of genomes from 1,167 bacterial species reveals that rrn copy number predicts traits associated with resource availability, including chemotaxis and genome streamlining. Genome-wide patterns of orthologous gene content covary with rrn copy number, suggesting convergent evolution in response to resource availability. Our findings imply that basic cellular processes adapt in contrasting ways to long-term differences in resource availability. They also establish a basis for predicting changes in bacterial community composition in response to resource perturbations using rrn copy number measurements 5 or inferences 6,7 .

The Mahabharata and reproductive endocrinology

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Bharti Kalra

2016-01-01

Full Text Available This communication approaches the Mahabharata through the prism of reproductive endocrinology. Descriptions of episodes related to reproduction are listed here, to provide fodder for the endocrinologically minded brain. The cases described here are perhaps, the first documented observations of fetal orgasm, pseudocyesis and assisted reproductive technology, including assisted insemination by donor, induction of ovulation, and in vitro fertilization as well as precocious growth and intersex. We do not presume to offer a definite explanation for these interesting episodes from the Mahabharata. We do, however, hope to stimulate interest in ancient Indian literature, and encourage a literary “forensic endocrine” analysis of events relevant to our specialty.

Herbivore-mediated ecological costs of reproduction shape the life history of an iteroparous plant.

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Miller, Tom E X; Tenhumberg, Brigitte; Louda, Svata M

2008-02-01

Plant reproduction yields immediate fitness benefits but can be costly in terms of survival, growth, and future fecundity. Life-history theory posits that reproductive strategies are shaped by trade-offs between current and future fitness that result from these direct costs of reproduction. Plant reproduction may also incur indirect ecological costs if it increases susceptibility to herbivores. Yet ecological costs of reproduction have received little empirical attention and remain poorly integrated into life-history theory. Here, we provide evidence for herbivore-mediated ecological costs of reproduction, and we develop theory to examine how these costs influence plant life-history strategies. Field experiments with an iteroparous cactus (Opuntia imbricata) indicated that greater reproductive effort (proportion of meristems allocated to reproduction) led to greater attack by a cactus-feeding insect (Narnia pallidicornis) and that damage by this herbivore reduced reproductive success. A dynamic programming model predicted strongly divergent optimal reproductive strategies when ecological costs were included, compared with when these costs were ignored. Meristem allocation by cacti in the field matched the optimal strategy expected under ecological costs of reproduction. The results indicate that plant reproductive allocation can strongly influence the intensity of interactions with herbivores and that associated ecological costs can play an important selective role in the evolution of plant life histories.

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.

Associations between intrauterine bacterial infection, reproductive tract inflammation, and reproductive performance in pasture-based dairy cows.

Science.gov (United States)

de Boer, Melvin; Buddle, Bryce M; Heuer, Cord; Hussein, Hassan; Zheng, Tao; LeBlanc, Stephen J; McDougall, Scott

2015-06-01

Reproductive tract bacterial infections, particularly those caused by Escherichia coli and Trueperella pyogenes, can have a negative impact on reproductive performance. It has been hypothesized that the presence of E coli early postpartum may increase the risk of isolation of T pyogenes later postpartum. The objective of the present study was to examine associations between intrauterine bacterial infections with E coli and T pyogenes and any bacterial growth (irrespective of bacterial species), purulent vaginal discharge (PVD), cytologic evidence of endometritis (an increased proportion of polymorphonuclear cells [PMNs]), and reproductive performance. Dairy cows (n = 272) from six herds were examined at Days 0 (median, 2 days in milk), 21 and 42 postpartum. From each cow two intrauterine samples were collected via triple-guarded cytobrush at Days 0 and 21. The first cytobrush was used for bacteriologic culture. Escherichia coli and T pyogenes were isolated by culture, and E coli isolates were assigned to one of four phylogenetic groups using a two-step triplex polymerase chain reaction. In addition, T pyogenes was confirmed by polymerase chain reaction. The second cytobrush was used to prepare a cytology slide. Nucleated cells (n = 200) were categorized as epithelial cells, PMNs, or macrophages. Cows were also assessed for body condition score, PVD score, the presence of a CL, and pregnancy. Statistical analysis was performed using multivariable models. There was no association between the presence of E coli at Day 0 and probability of isolation of T pyogenes 3 weeks later; however, E coli positive cows at Day 0 were more likely to be diagnosed with E coli at Day 21 (relative risk [RR] = 2.0, P bacterial growth at Day 21, irrespective of species, were less likely to conceive within 3 weeks after the start of the seasonal breeding program (RR = 0.8; P = 0.05). Interestingly, cows with 25% PMNs or greater at Day 0 had shorter time to pregnancy (hazard ratio = 1.32; P

Inductions of reproduction and population growth in the generalist predator Cyrtorhinus lividipennis (Hemiptera: Miridae) exposed to sub-lethal concentrations of insecticides.

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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.

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

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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

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....

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)

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....

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)

A MATHEMATICAL MODEL FOR THE KINETICS OF THE MALE REPRODUCTIVE ENDOCRINE SYSTEM

Science.gov (United States)

In this presentation a model for the hormonal regulation of the reproductive endocrine system in the adult male rat will be discussed. The model includes a description of the kinetics of the androgenic hormones testosterone and dihydrotestosterone, as well as the receptor-mediate...

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.

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.

Alteration in neonatal nutrition causes perturbations in hypothalamic neural circuits controlling reproductive function.

Science.gov (United States)

Caron, Emilie; Ciofi, Philippe; Prevot, Vincent; Bouret, Sebastien G

2012-08-15

It is increasingly accepted that alterations of the early life environment may have lasting impacts on physiological functions. In particular, epidemiological and animal studies have indicated that changes in growth and nutrition during childhood and adolescence can impair reproductive function. However, the precise biological mechanisms that underlie these programming effects of neonatal nutrition on reproduction are still poorly understood. Here, we used a mouse model of divergent litter size to investigate the effects of early postnatal overnutrition and undernutrition on the maturation of hypothalamic circuits involved in reproductive function. Neonatally undernourished females display attenuated postnatal growth associated with delayed puberty and defective development of axonal projections from the arcuate nucleus to the preoptic region. These alterations persist into adulthood and specifically affect the organization of neural projections containing kisspeptin, a key neuropeptide involved in pubertal activation and fertility. Neonatal overfeeding also perturbs the development of neural projections from the arcuate nucleus to the preoptic region, but it does not result in alterations in kisspeptin projections. These studies indicate that alterations in the early nutritional environment cause lasting and deleterious effects on the organization of neural circuits involved in the control of reproduction, and that these changes are associated with lifelong functional perturbations.

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.

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...... 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...... 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;9999:1-12. © 2017 SETAC....

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

OpenAIRE

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

2017-01-01

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 reprodu...

Towards Sustainable Growth Business Models

Energy Technology Data Exchange (ETDEWEB)

Kamp-Roelands, N.; Balkenende, J.P.; Van Ommen, P.

2012-03-15

The Dutch Sustainable Growth Coalition (DSGC) has the following objectives: The DSGC aims to pro-actively drive sustainable growth business models along three lines: (1) Shape. DSGC member companies aim to connect economic profitability with environmental and social progress on the basis of integrated sustainable growth business models; (2) Share. DSGC member companies aim for joint advocacy of sustainable growth business models both internationally and nationally; and (3) Stimulate. DSGC member companies aim to stimulate and influence the policy debate on enabling sustainable growth - with a view to finding solutions to the environmental and social challenges we are facing. This is their first report. The vision, actions and mission of DSGC are documented in the Manifesto in Chapter 2 of this publication. Chapter 3 contains an overview of key features of an integrated sustainable growth business model and the roadmap towards such a model. In Chapter 4, project examples of DSGC members are presented, providing insight into the hands-on reality of implementing the good practices. Chapter 5 offers an overview of how the Netherlands provides an enabling environment for sustainable growth business models. Chapter 6 offers the key conclusions.

Plant reproductive allocation predicts herbivore dynamics across spatial and temporal scales.

Science.gov (United States)

Miller, Tom E X; Tyre, Andrew J; Louda, Svata M

2006-11-01

Life-history theory suggests that iteroparous plants should be flexible in their allocation of resources toward growth and reproduction. Such plasticity could have consequences for herbivores that prefer or specialize on vegetative versus reproductive structures. To test this prediction, we studied the response of the cactus bug (Narnia pallidicornis) to meristem allocation by tree cholla cactus (Opuntia imbricata). We evaluated the explanatory power of demographic models that incorporated variation in cactus relative reproductive effort (RRE; the proportion of meristems allocated toward reproduction). Field data provided strong support for a single model that defined herbivore fecundity as a time-varying, increasing function of host RRE. High-RRE plants were predicted to support larger insect populations, and this effect was strongest late in the season. Independent field data provided strong support for these qualitative predictions and suggested that plant allocation effects extend across temporal and spatial scales. Specifically, late-season insect abundance was positively associated with interannual changes in cactus RRE over 3 years. Spatial variation in insect abundance was correlated with variation in RRE among five cactus populations across New Mexico. We conclude that plant allocation can be a critical component of resource quality for insect herbivores and, thus, an important mechanism underlying variation in herbivore abundance across time and space.

Reproductive cycles of deer.

Science.gov (United States)

Asher, G W

2011-04-01

The cervids are a complex assemblage of taxa showing extreme diversity in morphology, physiology, ecology and geographical distribution. Reproductive strategies adopted by various species are also diverse, and include a range from highly seasonal to completely aseasonal birth patterns. The recent growth in knowledge on cervid reproduction is strongly biased towards the larger-bodied, gregarious mixed grazer-browser species that have adapted well to human management and commercialisation. These species tend to represent 'K-selected' climax species characterised by very productive annual breeding success, singleton births and long breeding life (10+ years). Conversely, we know relatively little about the reproductive patterns of the 'r-selected' smaller-bodied, solitary (and often highly territorial), forest-dwelling browser species, often characterised by great fecundity (twinning) and shorter breeding life (<10 years). This group includes many of the endangered cervid taxa. This review extends earlier reviews to include more recent work on cervid reproductive cycles, particularly in relation to environmental factors influencing gestation length. Copyright © 2010 Elsevier B.V. All rights reserved.

[Studies on the growth and reproduction of bacterial communities on structural materials of the international space station].

Science.gov (United States)

Rakova, N M; Svistunova, Iu V; Novikova, N D

2005-01-01

Probability of microbial growth and reproduction on the ISS interior and equipment materials varying in chemical composition was studied with the strains of Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus saprophyticus, Pseudomonas putida etc. sampled from the ISS environment. Controls were ground reference strains of same bacterial species. Based on our results, some of the microorganisms are able to survive and proliferate on structural materials; the ability was greater in space isolates as compared with their ground analogs. The greatest ability to grow and proliferate on materials was demonstrated by Bacillus subtilis.

Effects of probiotic administration on zebrafish development and reproduction.

Science.gov (United States)

Carnevali, O; Avella, M A; Gioacchini, G

2013-07-01

As the consumption of probiotics increases worldwide, scientists focus on identifying bacterial strains able to improve human life quality and evidence the biological pathways affected by probiotic treatment. In this review, some recent observations on the effects of changes of microbiota on zebrafish metabolism were discussed. In addition, the effects of Lactobacillus rhamnosus - a component of the human gut microflora - as a diet supplement on Danio rerio were presented. When administered chronically, L. rhamnosus may affect larval development and the physiology of reproductive system in the zebrafish model. It was hypothesized exogenous L. rhamnosus accelerates larval growth and backbone development by acting on insulin-like growth factors-I (igfI) and -II (igfII), peroxisome proliferator activated receptors-α and -β, (pparα,β) vitamin D receptor-α (vdrα) and retinoic acid receptor-γ (rarγ). Gonadal differentiation was anticipated at 6weeks together with a higher expression of gnrh3 at the larval stage when L. rhamnosus was administered throughout development. Moreover, brood stock alimented with a L. rhamnosus-supplemented diet showed better reproductive performances as per follicles development, ovulated oocytes quantification and embryos quality. A plausible involvement of factors such as leptin, and kiss1 and 2 in the improvements was concluded. The observations made on the physiology of female reproduction were correlated with the gene expression of a gigantic number of factors as the aromatase cytochrome p 19 (cyp19a), the vitellogenin (vtg) and the α isoform of the E2 receptor (erα), luteinizing hormone receptor (lhr), 20-β hydroxysteroid dehydrogenase (20β-hsd), membrane progesterone receptors α and β, cyclin B, activinβA1, smad2, transforming growth factor β1 (tgfβ1), growth differentiation factor9 (gdf9) and bone morphogenetic protein15 (bmp15.) A model in which the exogenous L. rhamnosus in the digestive tract of zebrafish from the

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.

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.

[A Cellular Automata Model for a Community Comprising Two Plant Species of Different Growth Forms].

Science.gov (United States)

Frolov, P V; Zubkova, E V; Komarov, A S

2015-01-01

A cellular automata computer model for the interactions between two plant species of different growth forms--the lime hairgrass Deschampsia caespitosa (L.) P. Beauv., a sod cereal, and the moneywort Lysimachia nummularia L., a ground creeping perennial herb--is considered. Computer experiments on the self-maintenance of the populations of each species against the background of a gradual increase in the share of randomly eliminated individuals, coexistence of the populations of two species, and the effect of the phytogenous field have been conducted. As has been shown, all the studied factors determine the number of individuals and self-sustainability of the simulated populations by the degree of their impact. The limits of action have been determined for individual factors; within these limits, the specific features in plant reproduction and dispersal provide sustainable coexistence of the simulated populations. It has been demonstrated that the constructed model allows for studying the long-term developmental dynamics of the plants belonging to the selected growth forms.

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.

DETERMINATION OF PROCESSES OF USE, PRESERVING AND REPRODUCTION IN THE SYSTEM OF RENEWABLE NATURAL RESOURCES MANAGEMENT

Directory of Open Access Journals (Sweden)

Mikhail Gazuda

2015-11-01

Full Text Available The purpose of the paper is to develop factor model of renewable natural resources management, specifying the assessment of the amount of resource, including the natural factor, consumption level and intensity of reproduction. Methodology. The survey is based on highlighting factors influencing the reproductive capacity of natural environment. It allows, on the base of taking into consideration reproductive abilities of resources and intensity of consumption, to substantiate three models for their use, including: heavy exploitation of renewable natural resources as the most commonly used model at the current level of development of society; model of reproductive use of natural resources, stipulating for the interference from the side of authorities and management, and the model of simple reproduction of renewable natural resources, at which the resource itself and the amount of its reproduction for the next period remain constant. Practical implications. The need is substantiated in implementation of the new model for determination of the processes of managing balanced use of natural resources, which will stipulate processes of reproduction in the sphere of natural management, form new approaches to environmental protection and promote the optimal ratio between the consumption and reproduction of natural resources. At this, the processes of natural reproduction are influenced by the amount of resource itself, intensity of its reproduction and level of consumption. The main objective of the managing bodies in the sphere of the use of renewable natural resources should be securing optimal ratio between consumption and reproduction of such natural resources. The efficiency of the implementation process and reproduction of natural resources presupposes providing their simple and extended reproduction, economic effectiveness and sustainability in allocation and use of such resources. This will have positive effect on ecological and economic security

Reproductive sharing among queens in the ant Formica fusca

OpenAIRE

Minttumaaria Hannonen; Liselotte Sundstro¨m

2003-01-01

Reproductive sharing among cobreeders, in which reproductive shares may vary from equal contribution (low reproductive skew) to reproductive dominance by one individual (high reproductive skew), is a fundamental feature of animal societies. Recent theoretical work, the reproductive skew models, has focused on factors affecting the degree to which reproduction is skewed within a society. We used the parameters provided by skew models as a guideline to study determinants of reproductive sharing...

Perspective on a Modified Developmental and Reproductive Toxicity Testing Strategy for Cancer Immunotherapy.

Science.gov (United States)

Prell, Rodney A; Halpern, Wendy G; Rao, Gautham K

2016-05-01

The intent of cancer immunotherapy (CIT) is to generate and enhance T-cell responses against tumors. The tumor microenvironment establishes several inhibitory pathways that lead to suppression of the local immune response, which is permissive for tumor growth. The efficacy of different CITs, alone and in combination, stems from reinvigorating the tumor immune response via several mechanisms, including costimulatory agonists, checkpoint inhibitors, and vaccines. However, immune responses to other antigens (self and foreign) may also be enhanced, resulting in potentially undesired effects. In outbred mammalian pregnancies, the fetus expresses paternally derived alloantigens that are recognized as foreign by the maternal immune system. If unchecked or enhanced, maternal immunity to these alloantigens represents a developmental and reproductive risk and thus is a general liability for cancer immunotherapeutic molecules. We propose a tiered approach to confirm this mechanistic reproductive liability for CIT molecules. A rodent allopregnancy model is based on breeding 2 different strains of mice so that paternally derived alloantigens are expressed by the fetus. When tested with a cross-reactive biotherapeutic, small molecule drug, or surrogate molecule, this model should reveal on-target reproductive liabilities if the pathway is involved in maintaining pregnancy. Alternatively, allopregnancy models with genetically modified mice can be interrogated for exquisitely specific biotherapeutics with restricted species reactivity. The allopregnancy model represents a relatively straightforward approach to confirm an expected on-target reproductive risk for CIT molecules. For biotherapeutics, it could potentially replace more complex developmental and reproductive toxicity testing in nonhuman primates when a pregnancy hazard is confirmed or expected. © The Author(s) 2016.

Toll-like receptors in the gonads and reproductive tract: emerging roles in reproductive physiology and pathology.

Science.gov (United States)

Girling, Jane E; Hedger, Mark P

2007-01-01

Interactions between the immune system and reproductive system have important consequences for fertility and reproductive health in general. There is increasing evidence that many of the interactions between the immune and reproductive systems involve the Toll-like receptors (TLRs). While there is no doubt that TLRs are important in providing protection against infection in the reproductive tract, there is increasing evidence for the involvement of TLRs in more basic pathology and physiology of reproduction. In the female, TLRs have been implicated in critical aspects of ovarian, endometrial and placental function, as well as in ovarian cancer, pelvic inflammatory disease, intrauterine growth restriction, pre-eclampsia and preterm birth. In the male, TLRs appear to play a role in the control of testicular steroidogenesis and spermatogenesis in disease and, potentially, during normal function, as well. Recent studies also have begun to highlight the role of various TLRs in the aetiology of prostatitis and prostatic cancer. Given the nascent state of knowledge concerning this important area, it is clear that more studies are needed, which should provide valuable new insights into the biology of the TLRs and reproductive function in general.

Representing the acquisition and use of energy by individuals in agent-based models of animal populations

DEFF Research Database (Denmark)

Sibly, RS; Grimm, Volker; Johnston, Alice S.A.

2013-01-01

of physiological ecology to identify major issues confronting the modeller and to make recommendations about how energy budgets for use in ABMs should be constructed. Our proposal is that modelled animals forage as necessary to supply their energy needs for maintenance, growth and reproduction....... If there is sufficient energy intake, an animal allocates the energy obtained in the order: maintenance, growth, reproduction, energy storage, until its energy stores reach an optimal level. If there is a shortfall, the priorities for maintenance and growth/reproduction remain the same until reserves fall to a critical...

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.

Reproductive success and failure: the role of winter body mass in reproductive allocation in Norwegian moose.

Science.gov (United States)

Milner, Jos M; van Beest, Floris M; Solberg, Erling J; Storaas, Torstein

2013-08-01

A life history strategy that favours somatic growth over reproduction is well known for long-lived iteroparous species, especially in unpredictable environments. Risk-sensitive female reproductive allocation can be achieved by a reduced reproductive effort at conception, or the subsequent adjustment of investment during gestation or lactation in response to unexpected environmental conditions or resource availability. We investigated the relative importance of reduced investment at conception compared with later in the reproductive cycle (i.e. prenatal, perinatal or neonatal mortality) in explaining reproductive failure in two high-density moose (Alces alces) populations in southern Norway. We followed 65 multiparous, global positioning system (GPS)-collared females throughout the reproductive cycle and focused on the role of maternal nutrition during gestation in determining reproductive success using a quasi-experimental approach to manipulate winter forage availability. Pregnancy rates in early winter were normal (≥0.8) in all years while spring calving rates ranged from 0.4 to 0.83, with prenatal mortality accounting for most of the difference. Further losses over summer reduced autumn recruitment rates to 0.23-0.69, despite negligible predation. Over-winter mass loss explained variation in both spring calving and autumn recruitment success better than absolute body mass in early or late winter. Although pregnancy was related to body mass in early winter, overall reproductive success was unrelated to pre-winter body condition. We therefore concluded that reproductive success was limited by winter nutritional conditions. However, we could not determine whether the observed reproductive allocation adjustment was a bet-hedging strategy to maximise reproduction without compromising survival or whether females were simply unable to invest more resources in their offspring.

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

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...... of a mollusc reproduction test guideline. An ad hoc mollusc expert group has been formed in Europe to validate methods that can meet this need. Currently, a key species for use in this context is the freshwater gastropod Lymnaea stagnalis. An important aspect of this work is to first develop a specific...... pathogen free defined strain of L. stagnalis and second to establish a historical database of growth and reproductive rates under defined culturing conditions. A mass culture of the RENILYS® strain of L. stagnalis have been established at INRA (France) since 2002 and has been distributed to research...

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

Reproductive demography of a temperate protogynous and herbivorous fish, Odax pullus (Labridae, Odacini)

KAUST Repository

Laman Trip, Elizabeth; Raubenheimer, David; Clements, Kendall D.; Choat, John Howard

2011-01-01

A common view is that, in marine fishes, herbivory and sex change are subject to physiological constraints at high latitudes, which are likely to affect growth rates and reproductive outputs. The present study examines the reproductive demography of Odax pullus, an herbivorous and protogynous species of temperate New Zealand. We establish an otolith-based methodology for age estimation and investigate sex-specific growth, longevity and age-based reproductive events. Individuals achieved a maximum age of 11 years, reached 85% of adult body size (455mm FL) within the first 3.5 years of life, were sexually mature by the age of 1.11.5 years and changed sex at 2.83.5 years, indicating fast simultaneous somatic and reproductive growth. There was no significant difference in growth or body size between the sexes. Ovary weight of spawning females increased significantly with size and age, suggesting the presence of size- and age-fecundity skews underlying the absence of sex change in larger and older females. Testes of reproductively active males comprised less than 1% of bodyweight, suggesting pair-spawning and little sperm competition. The present study provides metrics to support comparisons of the demography of this temperate protogynous and herbivorous labrid across spatial or temporal strata. © CSIRO 2011.

Reproductive demography of a temperate protogynous and herbivorous fish, Odax pullus (Labridae, Odacini)

KAUST Repository

Laman Trip, Elizabeth

2011-03-07

A common view is that, in marine fishes, herbivory and sex change are subject to physiological constraints at high latitudes, which are likely to affect growth rates and reproductive outputs. The present study examines the reproductive demography of Odax pullus, an herbivorous and protogynous species of temperate New Zealand. We establish an otolith-based methodology for age estimation and investigate sex-specific growth, longevity and age-based reproductive events. Individuals achieved a maximum age of 11 years, reached 85% of adult body size (455mm FL) within the first 3.5 years of life, were sexually mature by the age of 1.11.5 years and changed sex at 2.83.5 years, indicating fast simultaneous somatic and reproductive growth. There was no significant difference in growth or body size between the sexes. Ovary weight of spawning females increased significantly with size and age, suggesting the presence of size- and age-fecundity skews underlying the absence of sex change in larger and older females. Testes of reproductively active males comprised less than 1% of bodyweight, suggesting pair-spawning and little sperm competition. The present study provides metrics to support comparisons of the demography of this temperate protogynous and herbivorous labrid across spatial or temporal strata. © CSIRO 2011.

Thyroid hormone actions on male reproductive system of teleost fish.

Science.gov (United States)

Tovo-Neto, Aldo; da Silva Rodrigues, Maira; Habibi, Hamid R; Nóbrega, Rafael Henrique

2018-04-17

Thyroid hormones (THs) play important roles in the regulation of many biological processes of vertebrates, such as growth, metabolism, morphogenesis and reproduction. An increasing number of studies have been focused on the involvement of THs in the male reproductive system of vertebrates, in particular of fish. Therefore, this mini-review aims to summarize the main findings on THs role in male reproductive system of fish, focusing on sex differentiation, testicular development and spermatogenesis. The existing data in the literature have demonstrated that THs exert their roles at the different levels of the hypothalamic-pituitary-gonadal (HPG) axis. In general a positive correlation has been shown between THs and fish reproductive status; where THs are associated with testicular development, growth and maturation. Recently, the molecular mechanisms underlying the role of THs in spermatogenesis have been unraveled in zebrafish testis. THs promote germ cell proliferation and differentiation by increasing a stimulatory growth factor of spermatogenesis produced by Sertoli cells. In addition, THs enhanced the gonadotropin-induced androgen release in zebrafish testis. Next to their functions in the adult testis, THs are involved in the gonadal sex differentiation through modulating sex-related gene expression, and testicular development via regulation of Sertoli cell proliferation. In conclusion, this mini-review showed that THs modulate the male reproductive system during the different life stages of fish. The physiological and molecular mechanisms showed a link between the thyroid and reproduction, suggesting a possibly co-evolution and interdependence of these two systems. Copyright © 2018 Elsevier Inc. All rights reserved.

Effect of TiO2 nanoparticles on the reproduction of silkworm.

Science.gov (United States)

Ni, Min; Li, Fanchi; Wang, Binbin; Xu, Kaizun; Zhang, Hua; Hu, Jingsheng; Tian, Jianghai; Shen, Weide; Li, Bing

2015-03-01

Silkworm (Bombyx mori) is an important economic insect and the model insect of Lepidoptera. Because of its high fecundity and short reproduction cycle, it has been widely used in reproduction and development research. The high concentrations of titanium dioxide nanoparticles (TiO2 NPs) show reproductive toxicity, while low concentrations of TiO2 NPs have been used as feed additive and demonstrated significant biological activities. However, whether the low concentrations of TiO2 NPs affect the reproduction of B. mori has not been reported. In this study, the growth and development of gonad of B. mori fed with a low concentration of TiO2 NPs (5 mg/L) were investigated by assessing egg production and expression of reproduction-related genes. The results showed that the low concentration of TiO2 NPs resulted in faster development of the ovaries and testes and more gamete differentiation and formation, with an average increase of 51 eggs per insect and 0.34 × 10(-4) g per egg after the feeding. The expressions of several reproduction-related genes were upregulated, such as the yolk-development-related genes Ovo-781 and vitellogenin (Vg) were increased by 5.33- and 6.77-folds, respectively. This study shows that TiO2 NPs feeding at low concentration can enhance the reproduction of B. mori, and these results are useful in developing new methods to improve fecundity in B. mori and providing new clues for its broad biological applications.

Fetal programming of sexual development and reproductive function.

Science.gov (United States)

Zambrano, Elena; Guzmán, Carolina; Rodríguez-González, Guadalupe L; Durand-Carbajal, Marta; Nathanielsz, Peter W

2014-01-25

The recent growth of interest in developmental programming of physiological systems has generally focused on the cardiovascular system (especially hypertension) and predisposition to metabolic dysfunction (mainly obesity and diabetes). However, it is now clear that the full range of altered offspring phenotypes includes impaired reproductive function. In rats, sheep and nonhuman primates, reproductive capacity is altered by challenges experienced during critical periods of development. This review will examine available experimental evidence across commonly studied experimental species for developmental programming of female and male reproductive function throughout an individual's life-course. It is necessary to consider events that occur during fetal development, early neonatal life and prior to and during puberty, during active reproductive life and aging as reproductive performance declines. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

A full lifecycle bioenergetic model for bluefin tuna.

NARCIS (Netherlands)

Jusup, M.; Klanjscek, T.; Matsuda, H.; Kooijman, S.A.L.M.

2011-01-01

We formulated a full lifecycle bioenergetic model for bluefin tuna relying on the principles of Dynamic Energy Budget theory. Traditional bioenergetic models in fish research deduce energy input and utilization from observed growth and reproduction. In contrast, our model predicts growth and

Reproduction of upland hardwood forests in the central states

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Ivan L. Sander; F. Bryan Clark

1971-01-01

This handbook summarizes data from studies of central hardwood reproduction after harvest cuttings ranging from single-tree selection cutting to complete clearcutting. Regardless of how the stands were cut, natural reproduction was always adequate to produce acceptable new stands; but the heavier cuttings favored intolerant species and faster growth of all species....

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.

Effects of hydrogen fluoride fumigation of bean plants on the growth, development, and reproduction of the Mexican bean beetle

Energy Technology Data Exchange (ETDEWEB)

Weinstein, L H; McCune, D C; Mancini, J F; van Leuken, P

1973-01-01

The growth and behavior of Mexican bean beetle populations on control and hydrogen fluoride-fumigated bean plants (P. vulgaris L.) were investigated to assess the effects of such fumigation on beetle growth, development and reproduction. Beetles that were cultured on HF-fumigated plants were generally lighter than controls, although the occurrence and magnitude of this effect depended upon stage of development, age, and sex of the adult beetle and the number of generations of culture on HF-fumigated plants. A consistently decreased mass of larvae cultured on HF-fumigated tissue pupated and enclosed three to six days later than controls, and the adults commenced reproductive activity with the same lag in time. Beetles cultured on the fumigated plants also contained greater amounts of fluoride than the controls, and the fluoride content of females was greater than that of males on both HF-fumigated and control plants. Beetles raised on fumigated plants laid fewer egg masses and fewer eggs per mass, although when the first generation was repeated at a later date there was no significant effect. Feeding activity was reduced in both larval and adult stages in beetles cultured on the fumigated plants, and adults showed less flight activity than controls. A difference in color of the elytra was also noted; beetles on HF-fumigated plants were paler than controls.

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

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

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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.

Reproduction traits, growth traits and age at first calving in Holstein heifers

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Bruna Silva Marestone

2014-02-01

Full Text Available The objective of this study was to verify the reproductive efficiency expressed by traits, interval from first to second calving (IDP, number of services per conception to the first calving (NSC1, number of services per conception for the second calving (NSC2, service period from the first to the second calving (PS and gestation lenght (PG of Holstein heifers. Data from 377 heifers from two herds, one in Santa Cruz do Rio Pardo, São Paulo and another in Rolândia, Paraná were analysed. The statistical model to analyze IDP, NSC1, NSC2, PS and PG included the fixed effect of Contemporary Group (CG. To analyze PG, it was also considered the effect of calf sex. To evaluate the growth performance and age at first calving (AFC, data from 360 Holstein heifers belonging to property in Rolândia were analysed. The model included the fixed effects of contemporary groups (CG and average daily gain from birth to 15 months (ADG. A similar model was used to analyze weigth at 458 dias (W458 and ADG, therefore considering only CG. The overall means of IDP, NSC1, NSC2, PS and PG, were 14.96 ± 3.94 months; 1.35 ± 0.71 services, 2.86 ± 2.37 services, 178.83 ± 118.73 days; 276.67± 5.65 days, respectively. Correlations were observed between the traits IDP and NSC2 of 72% (P<0.0001, between IDP and PS of 98% (P<0.0001 and between NCS2 and PS of 72% (P<0.0001. The gestation length of males and females showed estimated average of 277.53 ± 0.46 days and 276.33 ± 0.40 days, respectively, and the calf sex was source of variation on PG (P<0.05. Average daily gain was a significant source of variation on AFC and CG affected all traits studied. The estimated average for AFC was 24.18 ± 1.59 months, for W458 was 362.33 ± 36.24 kg and ADG was 0.704 ± 0.08 kg.

Correlated genetic effects on reproduction define a domestication syndrome in a forest tree

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Santos-del-Blanco, Luis; Alía, Ricardo; González-Martínez, Santiago C; Sampedro, Luis; Lario, Francisco; Climent, José

2015-01-01

Compared to natural selection, domestication implies a dramatic change in traits linked to fitness. A number of traits conferring fitness in the wild might be detrimental under domestication, and domesticated species typically differ from their ancestors in a set of traits known as the domestication syndrome. Specifically, trade-offs between growth and reproduction are well established across the tree of life. According to allocation theory, selection for growth rate is expected to indirectly alter life-history reproductive traits, diverting resources from reproduction to growth. Here we tested this hypothesis by examining the genetic change and correlated responses of reproductive traits as a result of selection for timber yield in the tree Pinus pinaster. Phenotypic selection was carried out in a natural population, and progenies from selected trees were compared with those of control trees in a common garden experiment. According to expectations, we detected a genetic change in important life-history traits due to selection. Specifically, threshold sizes for reproduction were much higher and reproductive investment relative to size significantly lower in the selected progenies just after a single artificial selection event. Our study helps to define the domestication syndrome in exploited forest trees and shows that changes affecting developmental pathways are relevant in domestication processes of long-lived plants. PMID:25926884

Activins in reproductive biology and beyond.

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Wijayarathna, R; de Kretser, D M

2016-04-01

Activins are members of the pleiotrophic family of the transforming growth factor-beta (TGF-β) superfamily of cytokines, initially isolated for their capacity to induce the release of FSH from pituitary extracts. Subsequent research has demonstrated that activins are involved in multiple biological functions including the control of inflammation, fibrosis, developmental biology and tumourigenesis. This review summarizes the current knowledge on the roles of activin in reproductive and developmental biology. It also discusses interesting advances in the field of modulating the bioactivity of activins as a therapeutic target, which would undoubtedly be beneficial for patients with reproductive pathology. A comprehensive literature search was carried out using PUBMED and Google Scholar databases to identify studies in the English language which have contributed to the advancement of the field of activin biology, since its initial isolation in 1987 until July 2015. 'Activin', 'testis', 'ovary', 'embryonic development' and 'therapeutic targets' were used as the keywords in combination with other search phrases relevant to the topic of activin biology. Activins, which are dimers of inhibin β subunits, act via a classical TGF-β signalling pathway. The bioactivity of activin is regulated by two endogenous inhibitors, inhibin and follistatin. Activin is a major regulator of testicular and ovarian development. In the ovary, activin A promotes oocyte maturation and regulates granulosa cell steroidogenesis. It is also essential in endometrial repair following menstruation, decidualization and maintaining pregnancy. Dysregulation of the activin-follistatin-inhibin system leads to disorders of female reproduction and pregnancy, including polycystic ovary syndrome, ectopic pregnancy, miscarriage, fetal growth restriction, gestational diabetes, pre-eclampsia and pre-term birth. Moreover, a rise in serum activin A, accompanied by elevated FSH, is characteristic of female

The reproductive cycle of the oyster Crassostrea gasar

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CHAM Gomes

Full Text Available The purpose of this study was to analyze the reproductive cycle of the oyster Crassostrea gasar (= C. brasiliana in the field and the laboratory. The reproductive cycle of the animals was evaluated in the field at Sambaqui Beach, Florianópolis, SC (27° 29′18″ S and 48° 32′12″ W from May 2008 through November 2009. In July, the animals were in the resting stage. The early growth stage began in August and was followed by the late growth stage in October. In November and December, the oysters began to enter the mature stage. Females in spawning condition were predominant during these months. The stages of the reproductive cycle were positively associated with temperature (r=0.77, P<0.01 and negatively associated with salinity (r=−0.56, P=0.042. These findings demonstrated that increased temperature and reduced salinity influence the reproductive development of Crassostrea gasar. The condition index (CI of the animals was also associated with the seawater temperature. The highest values of the condition index were observed during the months when the temperature of the seawater was gradually increasing. A laboratory experiment was performed to test the effect of salinity on the reproductive cycle of the oysters. The experiment was conducted in standardized tanks. The animals were conditioned using two salinities (24‰ and 34‰. The salinity regime influenced the development of the gonadal tissue of the oysters. A salinity of 24‰ produced greater reproductive development.

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

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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

Genetic differentiation for size at first reproduction through male versus female functions in the widespread Mediterranean tree Pinus pinaster.

Science.gov (United States)

Santos-del-Blanco, L; Climent, J; González-Martínez, S C; Pannell, J R

2012-11-01

The study of local adaptation in plant reproductive traits has received substantial attention in short-lived species, but studies conducted on forest trees are scarce. This lack of research on long-lived species represents an important gap in our knowledge, because inferences about selection on the reproduction and life history of short-lived species cannot necessarily be extrapolated to trees. This study considers whether the size for first reproduction is locally adapted across a broad geographical range of the Mediterranean conifer species Pinus pinaster. In particular, the study investigates whether this monoecious species varies genetically among populations in terms of whether individuals start to reproduce through their male function, their female function or both sexual functions simultaneously. Whether differences among populations could be attributed to local adaptation across a climatic gradient is then considered. Male and female reproduction and growth were measured during early stages of sexual maturity of a P. pinaster common garden comprising 23 populations sampled across the species range. Generalized linear mixed models were used to assess genetic variability of early reproductive life-history traits. Environmental correlations with reproductive life-history traits were tested after controlling for neutral genetic structure provided by 12 nuclear simple sequence repeat markers. Trees tended to reproduce first through their male function, at a size (height) that varied little among source populations. The transition to female reproduction was slower, showed higher levels of variability and was negatively correlated with vegetative growth traits. Several female reproductive traits were correlated with a gradient of growth conditions, even after accounting for neutral genetic structure, with populations from more unfavourable sites tending to commence female reproduction at a lower individual size. The study represents the first report of genetic

Leptin and reproduction: a review.

Science.gov (United States)

Moschos, Stergios; Chan, Jean L; Mantzoros, Christos S

2002-03-01

To review recent advances in understanding the role of leptin in the physiology and pathophysiology of reproduction, with a focus on relevant clinical situations. A MEDLINE computer search was performed to identify relevant articles. Leptin, an adipocyte hormone important in regulating energy homeostasis, interacts with the reproductive axis at multiple sites, with stimulatory effects at the hypothalamus and pituitary and inhibitory actions at the gonads. More recently, leptin has been shown to play a role in other target reproductive organs, such as the endometrium, placenta, and mammary gland, with corresponding influences on important physiologic processes such as menstruation, pregnancy, and lactation. As a marker of whether nutritional stores are adequate, leptin may act in concert with gonadotropins and the growth hormone axis to initiate the complex process of puberty. Conditions in which nutritional status is suboptimal, such as eating disorders, exercise-induced amenorrhea, and functional hypothalamic amenorrhea, are associated with low serum leptin levels; and conditions with excess energy stores or metabolic disturbances, such as obesity and polycystic ovarian syndrome, often have elevated serum or follicular fluid leptin levels, raising the possibility that relative leptin deficiency or resistance may be at least partly responsible for the reproductive abnormalities that occur with these conditions. Leptin may act as the critical link between adipose tissue and the reproductive system, indicating whether adequate energy reserves are present for normal reproductive function. Future interventional studies involving leptin administration are expected to further clarify this role of leptin and may provide new therapeutic options for the reproductive dysfunction associated with states of relative leptin deficiency or resistance.

Stochastic models for tumoral growth

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Escudero, Carlos

2006-02-01

Strong experimental evidence has indicated that tumor growth belongs to the molecular beam epitaxy universality class. This type of growth is characterized by the constraint of cell proliferation to the tumor border and the surface diffusion of cells at the growing edge. Tumor growth is thus conceived as a competition for space between the tumor and the host, and cell diffusion at the tumor border is an optimal strategy adopted for minimizing the pressure and helping tumor development. Two stochastic partial differential equations are reported in this paper in order to correctly model the physical properties of tumoral growth in (1+1) and (2+1) dimensions. The advantage of these models is that they reproduce the correct geometry of the tumor and are defined in terms of polar variables. An analysis of these models allows us to quantitatively estimate the response of the tumor to an unfavorable perturbation during growth.

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

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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.

Latent Growth and Dynamic Structural Equation Models.

Science.gov (United States)

Grimm, Kevin J; Ram, Nilam

2018-05-07

Latent growth models make up a class of methods to study within-person change-how it progresses, how it differs across individuals, what are its determinants, and what are its consequences. Latent growth methods have been applied in many domains to examine average and differential responses to interventions and treatments. In this review, we introduce the growth modeling approach to studying change by presenting different models of change and interpretations of their model parameters. We then apply these methods to examining sex differences in the development of binge drinking behavior through adolescence and into adulthood. Advances in growth modeling methods are then discussed and include inherently nonlinear growth models, derivative specification of growth models, and latent change score models to study stochastic change processes. We conclude with relevant design issues of longitudinal studies and considerations for the analysis of longitudinal data.

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.

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

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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.

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.

Root-lesion nematodes suppress cabbage aphid population development by reducing aphid daily reproduction

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W. H. Gera eHol

2016-02-01

Full Text Available Empirical studies have shown that belowground feeding herbivores can affect the performance of aboveground herbivores in different ways. Often the critical life-history parameters underlying the observed performance effects remain unexplored. In order to better understand the cause for the observed effects on aboveground herbivores, these ecological mechanisms must be better understood. In this study we combined empirical experiments with a modelling approach to analyse the effect of two root feeding endoparasitic nematodes with different feeding strategies on the population growth of the aboveground feeding specialist aphid Brevicoryne brassicae on Brassica nigra. The aim was to test whether emerging differences in life history characteristics (days until reproduction, daily reproduction would be sufficient to explain observed differences in aphid population development on plants with and without two species of nematodes. Aphid numbers were lower on plants with Pratylenchus penetrans in comparison to aphid numbers on plants with Meloidogyne spp. A dedicated experiment showed that aphid daily reproduction was lower on plants with P. penetrans (3.08 offspring per female per day in comparison to both uninfested plants and plants with Meloidogyne spp. (3.50 offspring per female per day. The species-specific reduction of aphid reproduction appeared independent of changes in amino acids, soluble sugars or the glucosinolate sinigrin in the phloem. An individual-based model revealed that relatively small differences in reproduction rate per female were sufficient to yield a similar difference in aphid populations as was found in the empirical experiments.

Impact of the environment on reproductive health.

Science.gov (United States)

1991-01-01

The WHO workshop on the impact of the environment on reproductive health is summarized. Topics include the nature of environmental factors affecting reproductive health, environmental factors blamed for declining sperm quantity and quality, the effects of natural and man-made disasters on reproductive health, chemical pollutants, how the environment damages reproductive health, and research needs for better research methodologies and surveillance data. Recommendations are made to: 1) promote international research collaboration with an emphasis on consistency of methodological approaches for assessing developmental and reproductive toxicity, on development of improved surveillance systems and data bases, an strengthening international disaster alert and evaluation systems; 2) promote research capabilities for multidisciplinary studies, for interactive studies of the environment and cellular processes, and for expansion of training and education; and 3) take action on priority problems of exposure to chemical, physical, and biological agents, of exposure to pesticides among specific populations, and of inadequate screening methods for identification of environmental chemicals. The costs of environmental injury to reproduction include subfertility, intrauterine growth retardation, spontaneous abortion, and various birth defects. Developed country's primary threats are from chemical pollution, radiation, and stress. There is a large gap in knowledge. Caution is urged in understanding the direct relationship between environmental causes and infertility. Sexual health is difficult to assess and research is suggested. Exposure to excessive vitamin A and toxic chemicals are cited as agents probably having serious effects on malformations. Sperm quality has declined over the decades; there is speculation about the potential causes. The effects of radiation such as at Chernobyl are described. Toxic chemical exposure such as in Bhopal, India killed thousands. Neurological

Effect of chronic ingestion of tritiated water and tritium organically bound in food on growth and reproductive functions of rats

International Nuclear Information System (INIS)

Pietrzak-Flis, Z.; Radwan, I.

1982-01-01

An effect of chronic ingestion of tritiated water and tritiated food on growth and reproduction of Wistar rats was evaluated. The animals were exposed during one or three successive generations. Ingestion of tritiated water at activity of 185.0 and 370.0 kBq/ml or tritiated food at activity of 144.3 kBq/g affected growth of the first generation (F 1 ) rats. In groups exposed to tritiated water the effect was transient. Exposure to tritiated food at 48.1 kBq/g or to tritiated water at the 37.0 kBq/ml affected the growth of F 2 generation rats only. A significant reduction in a relative testis tests weight was observed in a group exposed to tritiated water at activity of 370.0 kBq/ml, while sperm production was affected in all exposed groups. Ingestion of tritiated food caused higher reduction in sperm count than tritiated water. The effect of tritium on growth of rats and ability for sperm production depended on the absorbed dose and the form of ingested tritium. (author)

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.

Genetic parameter estimation of reproductive traits of Litopenaeus vannamei

Science.gov (United States)

Tan, Jian; Kong, Jie; Cao, Baoxiang; Luo, Kun; Liu, Ning; Meng, Xianhong; Xu, Shengyu; Guo, Zhaojia; Chen, Guoliang; Luan, Sheng

2017-02-01

In this study, the heritability, repeatability, phenotypic correlation, and genetic correlation of the reproductive and growth traits of L. vannamei were investigated and estimated. Eight traits of 385 shrimps from forty-two families, including the number of eggs (EN), number of nauplii (NN), egg diameter (ED), spawning frequency (SF), spawning success (SS), female body weight (BW) and body length (BL) at insemination, and condition factor (K), were measured,. A total of 519 spawning records including multiple spawning and 91 no spawning records were collected. The genetic parameters were estimated using an animal model, a multinomial logit model (for SF), and a sire-dam and probit model (for SS). Because there were repeated records, permanent environmental effects were included in the models. The heritability estimates for BW, BL, EN, NN, ED, SF, SS, and K were 0.49 ± 0.14, 0.51 ± 0.14, 0.12 ± 0.08, 0, 0.01 ± 0.04, 0.06 ± 0.06, 0.18 ± 0.07, and 0.10 ± 0.06, respectively. The genetic correlation was 0.99 ± 0.01 between BW and BL, 0.90 ± 0.19 between BW and EN, 0.22 ± 0.97 between BW and ED, -0.77 ± 1.14 between EN and ED, and -0.27 ± 0.36 between BW and K. The heritability of EN estimated without a covariate was 0.12 ± 0.08, and the genetic correlation was 0.90 ± 0.19 between BW and EN, indicating that improving BW may be used in selection programs to genetically improve the reproductive output of L. vannamei during the breeding. For EN, the data were also analyzed using body weight as a covariate (EN-2). The heritability of EN-2 was 0.03 ± 0.05, indicating that it is difficult to improve the reproductive output by genetic improvement. Furthermore, excessive pursuit of this selection is often at the expense of growth speed. Therefore, the selection of high-performance spawners using BW and SS may be an important strategy to improve nauplii production.

The type-reproduction number T in models for infectious disease control

NARCIS (Netherlands)

Heesterbeek, J.A.P.; Roberts, M.G.

A ubiquitous quantity in epidemic modelling is the basic reproduction number R0. This became so popular in the 1990s that ‘All you need know is R0!’ became a familiar catch-phrase. The value of R0 defines, among other things, the control effort needed to eliminate the infection from a homogeneous

Multiple growth-correlated life history traits estimated simultaneously in indivuals

NARCIS (Netherlands)

Mollet, F.M.; Ernande, B.; Brunel, T.P.A.; Rijnsdorp, A.D.

2010-01-01

We present a new methodology to estimate rates of energy acquisition, maintenance, reproductive investment and the onset of maturation (four-trait estimation) by fitting an energy allocation model to individual growth trajectories. The accuracy and precision of the method is evaluated on simulated

Reproductive strategy of common dentex Dentex dentex: management implications

Directory of Open Access Journals (Sweden)

A. GRAU

2016-07-01

Full Text Available Common dentex Dentex dentex is an iconic endangered species in the Mediterranean where is a sought after target species for small-scale, recreational and spearfishing fisheries. The reproductive biology of D. dentex in the natural environment is poorly known; therefore the reproductive strategy of the species was assessed by combining reproductive traits with the growth characteristics (estimated from length-at-age data, the size/age of sexual maturity and the energetic dynamics. A total of 358 wild fish were sampled on Mallorca Island (W Mediterranean from March 1996 to June 1999 with a 19 to 84.7 cm total length (LT range. The sex ratio was skewed towards females (1.361 albeit the length composition was not different between sexes (p = 0.551. Three young immature individuals (< 28 cm LT, 0.8% individuals were rudimentary hermaphrodites supporting the late gonochoristic species classification. The age composition determined from sagitta otolith interpretation ranged from 0 to 26 years (yr. Concerning growth, between sex differences in von Bertalanffy parameters were not relevant, even after accounting for potential between-year differences. The most noticeable difference was found for L∞ (64.7 cm for females versus 61.6 for males but even in this case, the bayesian credibility interval of between-sex differences included zero.  Maturity ogives at size and age showed that females achieved 50% maturity at 34.9 cm LT and 3.3 years, while males did at 33.8 cm LT and 2.5 years. The onset of gonad developing phase took place in December, while it progresses until April. The spawning peak was in April and May for both sexes. A generalized linear model showed that female size didn’t affect significantly the spawning season, whilst there was a strong seasonality in the spawning. Most of the evidences showed that fecundity is likely determinate, with an asynchronous oocyte development before spawning and a clear ovarian bimodal organization after

Layered growth model and epitaxial growth structures for SiCAlN alloys

International Nuclear Information System (INIS)

Liu Zhaoqing; Ni Jun; Su Xiaoao; Dai Zhenhong

2009-01-01

Epitaxial growth structures for (SiC) 1-x (AlN) x alloys are studied using a layered growth model. First-principle calculations are used to determine the parameters in the layered growth model. The phase diagrams of epitaxial growth are given. There is a rich variety of the new metastable polytype structures at x=1/6 ,1/5 ,1/4 ,1/3 , and 1/2 in the layered growth phase diagrams. We have also calculated the electronic properties of the short periodical SiCAlN alloys predicted by our layered growth model. The results show that various ordered structures of (SiC) 1-x (AlN) x alloys with the band gaps over a wide range are possible to be synthesized by epitaxial growth.

Life-history and spatial determinants of somatic growth dynamics in Komodo dragon populations.

Science.gov (United States)

Laver, Rebecca J; Purwandana, Deni; Ariefiandy, Achmad; Imansyah, Jeri; Forsyth, David; Ciofi, Claudio; Jessop, Tim S

2012-01-01

Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species.

Life-history and spatial determinants of somatic growth dynamics in Komodo dragon populations.

Directory of Open Access Journals (Sweden)

Rebecca J Laver

Full Text Available Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis. The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species.

Life-History and Spatial Determinants of Somatic Growth Dynamics in Komodo Dragon Populations

Science.gov (United States)

Laver, Rebecca J.; Purwandana, Deni; Ariefiandy, Achmad; Imansyah, Jeri; Forsyth, David; Ciofi, Claudio; Jessop, Tim S.

2012-01-01

Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world’s largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species. PMID:23028983

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.

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.

Growth Mechanism of Microbial Colonies

Science.gov (United States)

Zhu, Minhui; Martini, K. Michael; Kim, Neil H.; Sherer, Nicholas; Lee, Jia Gloria; Kuhlman, Thomas; Goldenfeld, Nigel

Experiments on nutrient-limited E. coli colonies, growing on agar gel from single cells reveal a power-law distribution of sizes, both during the growth process and in the final stage when growth has ceased. We developed a Python simulation to study the growth mechanism of the bacterial population and thus understand the broad details of the experimental findings. The simulation takes into account nutrient uptake, metabolic function, growth and cell division. Bacteria are modeled in two dimensions as hard circle-capped cylinders with steric interactions and elastic stress dependent growth characteristics. Nutrient is able to diffuse within and between the colonies. The mechanism of microbial colony growth involves reproduction of cells within the colonies and the merging of different colonies. We report results on the dynamic scaling laws and final state size distribution, that capture in semi-quantitative detail the trends observed in experiment. Supported by NSF Grant 0822613.

Life-history strategies of North American elk: trade-offs associated with reproduction and survival

Science.gov (United States)

Sabrina Morano; Kelley M. Stewart; James S. Sedinger; Christopher A. Nicolai; Marty Vavra

2013-01-01

The principle of energy allocation states that individuals should attempt to maximize fitness by allocating resources optimally among growth, maintenance, and reproduction. Such allocation may result in trade-offs between survival and reproduction, or between current and future reproduction. We used a marked population of North American elk (Cervus elaphus...

Habitat-specific population growth of a farmland bird.

Directory of Open Access Journals (Sweden)

Debora Arlt

Full Text Available BACKGROUND: To assess population persistence of species living in heterogeneous landscapes, the effects of habitat on reproduction and survival have to be investigated. METHODOLOGY/PRINCIPAL FINDINGS: We used a matrix population model to estimate habitat-specific population growth rates for a population of northern wheatears Oenanthe oenanthe breeding in farmland consisting of a mosaic of distinct habitat (land use types. Based on extensive long-term data on reproduction and survival, habitats characterised by tall field layers (spring- and autumn-sown crop fields, ungrazed grasslands displayed negative stochastic population growth rates (log lambda(s: -0.332, -0.429, -0.168, respectively, that were markedly lower than growth rates of habitats characterised by permanently short field layers (pastures grazed by cattle or horses, and farmyards, log lambda(s: -0.056, +0.081, -0.059. Although habitats differed with respect to reproductive performance, differences in habitat-specific population growth were largely due to differences in adult and first-year survival rates, as shown by a life table response experiment (LTRE. CONCLUSIONS/SIGNIFICANCE: Our results show that estimation of survival rates is important for realistic assessments of habitat quality. Results also indicate that grazed grasslands and farmyards may act as source habitats, whereas crop fields and ungrazed grasslands with tall field layers may act as sink habitats. We suggest that the strong decline of northern wheatears in Swedish farmland may be linked to the corresponding observed loss of high quality breeding habitat, i.e. grazed semi-natural grasslands.

Effects of growth curve plasticity on size-structured population dynamics

DEFF Research Database (Denmark)

Zhang, Lai; Lin, Zhigui; Pedersen, Michael

2011-01-01

The physiological-structured population models assume that a fixed fraction of energy intake is utilized for individual growth and maintenance while the remaining for adult fertility. The assumption results in two concerns: energy loss for juveniles and a reproduction dilemma for adults. The dile...

Positive Periodic Solutions of an Epidemic Model with Seasonality

Directory of Open Access Journals (Sweden)

Gui-Quan Sun

2013-01-01

Full Text Available An SEI autonomous model with logistic growth rate and its corresponding nonautonomous model are investigated. For the autonomous case, we give the attractive regions of equilibria and perform some numerical simulations. Basic demographic reproduction number Rd is obtained. Moreover, only the basic reproduction number R0 cannot ensure the existence of the positive equilibrium, which needs additional condition Rd>R1. For the nonautonomous case, by introducing the basic reproduction number defined by the spectral radius, we study the uniform persistence and extinction of the disease. The results show that for the periodic system the basic reproduction number is more accurate than the average reproduction number.

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 I

Characterizing the reproduction number of epidemics with early subexponential growth dynamics

DEFF Research Database (Denmark)

Chowell, Gerardo; Viboud, Cécile; Simonsen, Lone

2016-01-01

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...... 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...

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.

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.

Investigating Health Belief model component about sexual and reproductive health in college female students

Directory of Open Access Journals (Sweden)

Akram Aslani

2016-05-01

Full Text Available Background and objective: One of the critical steps in providing social and family health by concentrating on women's health is expanding sexual and reproductive health and addressing it in various aspects of the national and international level. Therefore in this study the goal is analyzing the components of the health belief model about sexual and reproductive health of female students of University of Medical Sciences of Shahroud. Methods: The present study is a cross-sectional analysis which conducted by participation of 397 female students of University of Medical Sciences of Shahroud in 2014. The data collecting tool was a questionnaire that was consisted of demographic information, knowledge and structures of health belief model. The data was analyzed by SPSS software and t-test and chi-square test. Results: The results showed that students had high self-efficacy (17.7 ± 2 in reproductive health care but the rate of their perceived barriers (3.02± 1.37 that was reported was almost high. Also there was a direct relation between demographic variable of age and the knowledge of students. The average score of students' awareness of sexually transmitted disease that was obtained was 9.97 ± 2.62. There was no significant relationship between age, marital status and their study major with structures of health belief model about sexually transmitted diseases and AIDS and its preventive behaviors. Conclusion: The findings of this study show that the self-efficacy of students about preventive behaviors of unwanted pregnancy and sexually transmitted diseases and AIDS is high. In other hand the average of perceived barriers in students is relatively high. Considering the findings it is recommended that sexual and reproductive health programs should be applied in order to reduce the barriers and to further increase the ability of young people. Paper Type: Research Article.

Migration and reproductive behavior in Turkish migrant families

OpenAIRE

Nauck, Bernhard

1987-01-01

Migration and reproductive behavior in Turkish migrant families : a situational explanation. - In: Growth and progress in cross-cultural psychology / ed. by Cigdem Kagitcibasi. - Lisse u.a. : Swets & Zeitlinger, 1987. - S. 336- 345

Heparin for assisted reproduction.

Science.gov (United States)

Akhtar, Muhammad A; Sur, Shyamaly; Raine-Fenning, Nick; Jayaprakasan, Kannamannadiar; Thornton, Jim G; Quenby, Siobhan

2013-08-17

Heparin as an adjunct in assisted reproduction (peri-implantation heparin) is given at or after egg collection or at embryo transfer during assisted reproduction. Heparin has been advocated to improve embryo implantation and clinical outcomes.  It has been proposed that heparin enhances the intra-uterine environment by improving decidualisation with an associated activation of growth factors and a cytokine expression profile in the endometrium that is favourable to pregnancy. To investigate whether the administration of heparin around the time of implantation (peri-implantation heparin) improves clinical outcomes in subfertile women undergoing assisted reproduction. A comprehensive and exhaustive search strategy was developed in consultation with the Trials Search Co-ordinator of the Cochrane Menstrual Disorders and Subfertility Group (MDSG). The strategy was used in an attempt to identify all relevant studies regardless of language or publication status (published, unpublished, in press, and in progress). Relevant trials were identified from both electronic databases and other resources (last search 6 May 2013). All randomised controlled trials (RCTs) were included where peri-implantation heparin was given during assisted reproduction. Peri-implantation low molecular weight heparin (LMWH) during IVF/ICSI was given at or after egg collection or at embryo transfer in the included studies. Live birth rate was the primary outcome. Two review authors independently assessed the eligibility and quality of trials and extracted relevant data. The quality of the evidence was evaluated using GRADE methods. Three RCTs (involving 386 women) were included in the review.Peri-implantation LMWH administration during assisted reproduction was associated with a significant improvement in live birth rate compared with placebo or no LMWH (odds ratio (OR) 1.77, 95% confidence interval (CI) 1.07 to 2.90, three studies, 386 women, I(2) = 51%, very low quality evidence with high

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.

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.

A new modified resource budget model for nonlinear dynamics in citrus production

International Nuclear Information System (INIS)

Ye, Xujun; Sakai, Kenshi

2016-01-01

Highlights: • A theoretical modeling and simulation study of the nonlinear dynamics in citrus is conducted. • New leaf growth is incorporated into the model as a major factor responsible for the yield oscillations. • A Ricker-type equation for the relationship between costs for flowering and fruiting is proposed. • A generic form of the resource budget model for the nonlinear dynamics in citrus is obtained. • The new model is tested with experimental data for two citrus trees. - Abstract : Alternate bearing or masting is a general yield variability phenomenon in perennial tree crops. This paper first presents a theoretical modeling and simulation study of the mechanism for this dynamics in citrus, and then provides a test of the proposed models using data from a previous 16-year experiment in a citrus orchard. Our previous studies suggest that the mutual effects between vegetative and reproductive growths caused by resource allocation and budgeting in plant body might be considered as a major factor responsible for the yield oscillations in citrus. Based on the resource budget model proposed by Isagi et al. (J Theor Biol. 1997;187:231-9), we first introduce the new leaf growth as a major energy consumption component into the model. Further, we introduce a nonlinear Ricker-type equation to replace the linear relationship between costs for flowering and fruiting used in Isagi's model. Model simulations demonstrate that the proposed new models can successfully simulate the reproductive behaviors of citrus trees with different fruiting dynamics. These results may enrich the mechanical dynamics in tree crop reproductive models and help us to better understand the dynamics of vegetative-reproductive growth interactions in a real environment.

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.

Effect of prepubertal and postpubertal growth and age at first calving on production and reproduction traits during the first 3 lactations in Holstein dairy cattle.

Science.gov (United States)

Krpálková, L; Cabrera, V E; Vacek, M; Stípková, M; Stádník, L; Crump, P

2014-05-01

The objective of this study was to evaluate the effect of body condition score (BCS), body weight (BW), average daily weight gain (ADG), and age at first calving (AFC) of Holstein heifers on production and reproduction parameters in the 3 subsequent lactations. The data set consisted of 780 Holstein heifers calved at 2 dairy farms in the Czech Republic from 2007 to 2011. Their BW and BCS were measured at monthly intervals during the rearing period (5 to 18 mo of age), and the milk production and reproduction data of the first 3 lactations were collected over an 8-yr period (2005 to 2012). The highest milk yield in the first lactation was found in the group with medium ADG (5 to 14 mo of age; 0.949 to 0.850 kg of ADG). The highest average milk yield over lifetime performance was detected in heifers with the highest total ADG (≥ 0.950 kg/d). The difference in milk yield between the evaluated groups of highest ADG (in total and postpubertal growth ≥ 0.950 kg/d and in prepubertal growth ≥ 0.970 kg/d) and the lowest ADG (≤ 0.849 kg/d) was approximately 1,000 kg/305 d per cow. The highest milk yield in the first lactation was found in the group with the highest AFC ≥ 751 d, for which fat and protein content in the milk was not reduced. Postpubertal growth (11 to 14 mo of age) had the greatest effect on AFC. The group with lowest AFC ≤ 699 d showed a negative effect on milk yield but only in the first 100 d of the first parity. The highest ADG was detrimental to reproduction parameters in the first lactation. The highest BW at 14 mo (≥ 420 kg) led to lower AFC. Groups according to BCS at 14 mo showed no differences in AFC or milk yield in the first lactation or lifetime average production per lactation. We concluded that low AFC ≤ 699 d did not show a negative effect on subsequent production and reproduction parameters. Therefore, a shorter rearing period is recommended for dairy herds with suitable management. Copyright © 2014 American Dairy Science

Fast-slow continuum and reproductive strategies structure plant life-history variation worldwide.

Science.gov (United States)

Salguero-Gómez, Roberto; Jones, Owen R; Jongejans, Eelke; Blomberg, Simon P; Hodgson, David J; Mbeau-Ache, Cyril; Zuidema, Pieter A; de Kroon, Hans; Buckley, Yvonne M

2016-01-05

The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population performance. We show that 55% of the variation in plant life-history strategies is adequately characterized using two independent axes: the fast-slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other. Our findings remain consistent across major habitats and are minimally affected by plant growth form and phylogenetic ancestry, suggesting that the relative independence of the fast-slow and reproduction strategy axes is general in the plant kingdom. Our findings have similarities with how life-history strategies are structured in mammals, birds, and reptiles. The position of plant species populations in the 2D space produced by both axes predicts their rate of recovery from disturbances and population growth rate. This life-history framework may complement trait-based frameworks on leaf and wood economics; together these frameworks may allow prediction of responses of plants to anthropogenic disturbances and changing environments.

Sexually Dimorphic Gene Expression Associated with Growth and Reproduction of Tongue Sole (Cynoglossus semilaevis) Revealed by Brain Transcriptome Analysis.

Science.gov (United States)

Wang, Pingping; Zheng, Min; Liu, Jian; Liu, Yongzhuang; Lu, Jianguo; Sun, Xiaowen

2016-08-26

In this study, we performed a comprehensive analysis of the transcriptome of one- and two-year-old male and female brains of Cynoglossus semilaevis by high-throughput Illumina sequencing. A total of 77,066 transcripts, corresponding to 21,475 unigenes, were obtained with a N50 value of 4349 bp. Of these unigenes, 33 genes were found to have significant differential expression and potentially associated with growth, from which 18 genes were down-regulated and 12 genes were up-regulated in two-year-old males, most of these genes had no significant differences in expression among one-year-old males and females and two-year-old females. A similar analysis was conducted to look for genes associated with reproduction; 25 genes were identified, among them, five genes were found to be down regulated and 20 genes up regulated in two-year-old males, again, most of the genes had no significant expression differences among the other three. The performance of up regulated genes in Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was significantly different between two-year-old males and females. Males had a high gene expression in genetic information processing, while female's highly expressed genes were mainly enriched on organismal systems. Our work identified a set of sex-biased genes potentially associated with growth and reproduction that might be the candidate factors affecting sexual dimorphism of tongue sole, laying the foundation to understand the complex process of sex determination of this economic valuable species.

Sexually Dimorphic Gene Expression Associated with Growth and Reproduction of Tongue Sole (Cynoglossus semilaevis Revealed by Brain Transcriptome Analysis

Directory of Open Access Journals (Sweden)

Pingping Wang

2016-08-01

Full Text Available In this study, we performed a comprehensive analysis of the transcriptome of one- and two-year-old male and female brains of Cynoglossus semilaevis by high-throughput Illumina sequencing. A total of 77,066 transcripts, corresponding to 21,475 unigenes, were obtained with a N50 value of 4349 bp. Of these unigenes, 33 genes were found to have significant differential expression and potentially associated with growth, from which 18 genes were down-regulated and 12 genes were up-regulated in two-year-old males, most of these genes had no significant differences in expression among one-year-old males and females and two-year-old females. A similar analysis was conducted to look for genes associated with reproduction; 25 genes were identified, among them, five genes were found to be down regulated and 20 genes up regulated in two-year-old males, again, most of the genes had no significant expression differences among the other three. The performance of up regulated genes in Gene Ontology (GO and Kyoto Encyclopedia of Genes and Genomes (KEGG pathway enrichment analysis was significantly different between two-year-old males and females. Males had a high gene expression in genetic information processing, while female’s highly expressed genes were mainly enriched on organismal systems. Our work identified a set of sex-biased genes potentially associated with growth and reproduction that might be the candidate factors affecting sexual dimorphism of tongue sole, laying the foundation to understand the complex process of sex determination of this economic valuable species.

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.

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

International Nuclear Information System (INIS)

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

1987-01-01

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

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.

Rethinking reproductive "tourism" as reproductive "exile".

Science.gov (United States)

Inhorn, Marcia C; Patrizio, Pasquale

2009-09-01

Whereas reproductive "tourism" implies leisure travel, reproductive "exile" bespeaks the numerous difficulties and constraints faced by infertile patients who are "forced" to travel globally for assisted reproduction. Given this reality, it is time to rethink the language of "reproductive tourism," replacing it with more accurate and patient-centered terms.

Relative effects of survival and reproduction on the population dynamics of emperor geese

Science.gov (United States)

Schmutz, Joel A.; Rockwell, Robert F.; Petersen, Margaret R.

1997-01-01

Populations of emperor geese (Chen canagica) in Alaska declined sometime between the mid-1960s and the mid-1980s and have increased little since. To promote recovery of this species to former levels, managers need to know how much their perturbations of survival and/or reproduction would affect population growth rate (λ). We constructed an individual-based population model to evaluate the relative effect of altering mean values of various survival and reproductive parameters on λ and fall age structure (AS, defined as the proportion of juv), assuming additive rather than compensatory relations among parameters. Altering survival of adults had markedly greater relative effects on λ than did equally proportionate changes in either juvenile survival or reproductive parameters. We found the opposite pattern for relative effects on AS. Due to concerns about bias in the initial parameter estimates used in our model, we used 5 additional sets of parameter estimates with this model structure. We found that estimates of survival based on aerial survey data gathered each fall resulted in models that corresponded more closely to independent estimates of λ than did models that used mark-recapture estimates of survival. This disparity suggests that mark-recapture estimates of survival are biased low. To further explore how parameter estimates affected estimates of λ, we used values of survival and reproduction found in other goose species, and we examined the effect of an hypothesized correlation between an individual's clutch size and the subsequent survival of her young. The rank order of parameters in their relative effects on λ was consistent for all 6 parameter sets we examined. The observed variation in relative effects on λ among the 6 parameter sets is indicative of how relative effects on λ may vary among goose populations. With this knowledge of the relative effects of survival and reproductive parameters on λ, managers can make more informed decisions about

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.

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.

Oxytocin--its role in male reproduction and new potential therapeutic uses.

Science.gov (United States)

Thackare, Hemlata; Nicholson, Helen D; Whittington, Kate

2006-01-01

Oxytocin (OT) is traditionally thought of as a "female" neurohypophysis hormone due to its role in parturition and milk ejection. However, OT is recognized as having endocrine and paracrine roles in male reproduction. At ejaculation, a burst of OT is released from the neurohypophysis into the systemic circulation and stimulates contractions of the reproductive tract aiding sperm release. There is conclusive evidence that OT is synthesized within the mammalian testis, epididymis and prostate and the presence of OT receptors (OTRs) through the reproductive tract supports a local action for this peptide. OT has a paracrine role in stimulating contractility of the seminiferous tubules, epididymis and the prostate gland. Interestingly, OT has also been shown to modulate androgen levels in these tissues via stimulation of the conversion of testosterone to dihydrotestostone (DHT) by 5alpha-reductase. The elucidation of OT's role in male reproduction has suggested a number of potential therapeutic uses for this hormone. Exogenous administration of OT has, in some cases, been shown to increase the numbers of ejaculated sperm, possibly by stimulating contractions of the reproductive tract and thus aiding sperm passage. Within the prostate, OT has been shown to affect gland growth both directly and via its interaction with androgen metabolism. Prostate pathologies due to unregulated cell proliferation/growth, such as benign prostatic hyperplasia and cancer, are unfortunately very common and few effective treatments are available. Greater understanding of paracrine growth mediators, such as OT, is likely to provide new mechanisms for treating such pathologies.

Franchising reproductive health services.

Science.gov (United States)

Stephenson, Rob; Tsui, Amy Ong; Sulzbach, Sara; Bardsley, Phil; Bekele, Getachew; Giday, Tilahun; Ahmed, Rehana; Gopalkrishnan, Gopi; Feyesitan, Bamikale

2004-12-01

Networks of franchised health establishments, providing a standardized set of services, are being implemented in developing countries. This article examines associations between franchise membership and family planning and reproductive health outcomes for both the member provider and the client. Regression models are fitted examining associations between franchise membership and family planning and reproductive health outcomes at the service provider and client levels in three settings. Franchising has a positive association with both general and family planning client volumes, and the number of family planning brands available. Similar associations with franchise membership are not found for reproductive health service outcomes. In some settings, client satisfaction is higher at franchised than other types of health establishments, although the association between franchise membership and client outcomes varies across the settings. Franchise membership has apparent benefits for both the provider and the client, providing an opportunity to expand access to reproductive health services, although greater attention is needed to shift the focus from family planning to a broader reproductive health context.

The guinea pig as an animal model for developmental and reproductive toxicology studies.

Science.gov (United States)

Rocca, Meredith S; Wehner, Nancy G

2009-04-01

Regulatory guidelines for developmental and reproductive toxicology (DART) studies require selection of "relevant" animal models as determined by kinetic, pharmacological, and toxicological data. Traditionally, rats, mice, and rabbits are the preferred animal models for these studies. However, for test articles that are pharmacologically inactive in the traditional animal models, the guinea pig may be a viable option. This choice should not be made lightly, as guinea pigs have many disadvantages compared to the traditional species, including limited historical control data, variability in pregnancy rates, small and variable litter size, long gestation, relative maturity at birth, and difficulty in dosing and breeding. This report describes methods for using guinea pigs in DART studies and provides results of positive and negative controls. Standard study designs and animal husbandry methods were modified to allow mating on the postpartum estrus in fertility studies and were used for producing cohorts of pregnant females for developmental studies. A positive control study with the pregnancy-disrupting agent mifepristone resulted in the anticipated failure of embryo implantation and supported the use of the guinea pig model. Control data for reproductive endpoints collected from 5 studies are presented. In cases where the traditional animal models are not relevant, the guinea pig can be used successfully for DART studies. (c) 2009 Wiley-Liss, Inc.

Do persistently fast-growing juveniles contribute disproportionately to population growth? A new analysis tool for matrix models and its application to rainforest trees.

Science.gov (United States)

Zuidema, Pieter A; Brienen, Roel J W; During, Heinjo J; Güneralp, Burak

2009-11-01

Plants and animals often exhibit strong and persistent growth variation among individuals within a species. Persistently fast-growing individuals have a higher chance of reaching reproductive size, do so at a younger age, and therefore contribute disproportionately to population growth (lambda). Here we introduce a new approach to quantify this "fast-growth effect." We propose using age-size-structured matrix models in which persistently fast and slow growers are distinguished as they occur in relatively young and old age classes for a given size category. Life-cycle pathways involving fast growth can then be identified, and their contribution to lambda is quantified through loop analysis. We applied this approach to an example species, the tropical rainforest tree Cedrela odorata, that shows persistent growth variation among individuals. Loop analysis showed that juvenile trees reaching the 10-cm diameter class at below-median age contributed twice as much to lambda as slow juvenile growers. Fast growth to larger-diameter categories also contributed disproportionately to lambda. The results were robust to changes in parameter values and life-history trade-offs. These results show that the fast-growth effect can be strong in long-lived species. Persistent growth differences among individuals should therefore be accommodated for in demographic models and life-history studies.

Adaptation of reproductive phenology to climate change with ecological feedback via dominance hierarchies.

Science.gov (United States)

Johansson, Jacob; Smith, Henrik G; Jonzén, Niclas

2014-03-01

Phenological shifts belong to the most commonly observed biological responses to recent climate change. It is, however, often unclear how these shifts are linked to demography and competitive interactions. We develop an eco-evolutionary model to study adaptation of timing of reproduction in organisms with social dominance hierarchies. We focus on residential birds with winter flocks, where success in competition for territories among offspring depends on ranking given by prior residence. We study the effects of environmental change on breeding population densities, ensuing selection pressures and long-term evolutionary equilibria. We consider changes in food peak date, in winter survival, in total reproductive output and in the width of the food distribution. We show that the evolutionarily stable hatching date will advance with increasing winter survival and reproductive output since these parameters increase habitat saturation and post-fledging competition. Increasing the length of the breeding season also selects for earlier hatching date due to the reduced costs for producing offspring with high ranking. Our analysis shows that there is little correlation between short-term and long-term population responses across different scenarios of environmental change. However, short-term population growth consistently predicts selection for earlier reproduction. Hence, the model identifies changed breeding population density as a key factor to understanding phenological adaptation in systems with prior residence advantages. While selection for change in reproductive phenology is often explained by changed seasonal variation in environmental variables, such as food abundance, we show that environmental change without apparent effects on seasonality can critically affect phenological adaptation. Such factors can mask or even override influences of changed seasonality on phenology. The model thus offers a conceptually new set of explanations for understanding phenological

A full lifecycle bioenergetic model for bluefin tuna.

Directory of Open Access Journals (Sweden)

Marko Jusup

Full Text Available We formulated a full lifecycle bioenergetic model for bluefin tuna relying on the principles of Dynamic Energy Budget theory. Traditional bioenergetic models in fish research deduce energy input and utilization from observed growth and reproduction. In contrast, our model predicts growth and reproduction from food availability and temperature in the environment. We calibrated the model to emulate physiological characteristics of Pacific bluefin tuna (Thunnus orientalis, hereafter PBT, a species which has received considerable scientific attention due to its high economic value. Computer simulations suggest that (i the main cause of different growth rates between cultivated and wild PBT is the difference in average body temperature of approximately 6.5°C, (ii a well-fed PBT individual can spawn an average number of 9 batches per spawning season, (iii food abundance experienced by wild PBT is rather constant and sufficiently high to provide energy for yearly reproductive cycle, (iv energy in reserve is exceptionally small, causing the weight-length relationship of cultivated and wild PBT to be practically indistinguishable and suggesting that these fish are poorly equipped to deal with starvation, (v accelerated growth rate of PBT larvae is connected to morphological changes prior to metamorphosis, while (vi deceleration of growth rate in the early juvenile stage is related to efficiency of internal heat production. Based on these results, we discuss a number of physiological and ecological traits of PBT, including the reasons for high Feed Conversion Ratio recorded in bluefin tuna aquaculture.

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.

A multiscale coupled finite-element and phase-field framework to modeling stressed grain growth in polycrystalline thin films

Energy Technology Data Exchange (ETDEWEB)

Jamshidian, M., E-mail: jamshidian@cc.iut.ac.ir [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Institute of Structural Mechanics, Bauhaus-University Weimar, Marienstrasse 15, 99423 Weimar (Germany); Thamburaja, P., E-mail: prakash.thamburaja@gmail.com [Department of Mechanical & Materials Engineering, Universiti Kebangsaan Malaysia (UKM), Bangi 43600 (Malaysia); Rabczuk, T., E-mail: timon.rabczuk@tdt.edu.vn [Division of Computational Mechanics, Ton Duc Thang University, Ho Chi Minh City (Viet Nam); Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City (Viet Nam)

2016-12-15

A previously-developed finite-deformation- and crystal-elasticity-based constitutive theory for stressed grain growth in cubic polycrystalline bodies has been augmented to include a description of excess surface energy and grain-growth stagnation mechanisms through the use of surface effect state variables in a thermodynamically-consistent manner. The constitutive theory was also implemented into a multiscale coupled finite-element and phase-field computational framework. With the material parameters in the constitutive theory suitably calibrated, our three-dimensional numerical simulations show that the constitutive model is able to accurately predict the experimentally-determined evolution of crystallographic texture and grain size statistics in polycrystalline copper thin films deposited on polyimide substrate and annealed at high-homologous temperatures. In particular, our numerical analyses show that the broad texture transition observed in the annealing experiments of polycrystalline thin films is caused by grain growth stagnation mechanisms. - Graphical abstract: - Highlights: • Developing a theory for stressed grain growth in polycrystalline thin films. • Implementation into a multiscale coupled finite-element and phase-field framework. • Quantitative reproduction of the experimental grain growth data by simulations. • Revealing the cause of texture transition to be due to the stagnation mechanisms.

Reproductive life of Bhoksa women.

Science.gov (United States)

Garg, S K; Tyagi, D; Sankhyan, A R

1981-01-01

The paper discusses the reproductive life of 111 ever-married Bhoksa women. The mean age at marriage for women of all ages among Bhoksas, like other tribal populations, is high, unlike the caste populations. The mean ages at first birth of the pooled sample and of the completed fertility cases suggest late and early marriages of the older and younger generations. The maximum number of marriages occur between 15 and 19 years and of first births between 16 and 20 years. Percentage of reproductive wastage is high in both the lower and higher age groups. Young mothers with low birth orders and older mothers with high birth orders display a high frequency of reproductive wastage. Evidently, both birth order and the age of the mother have effects on reproductive wastage. Average number of children ever born (including stillbirth but not abortion or miscarriage) per mother of all ages is the highest among Bhoksas of all the studied ethnic groups of India. The Bhoksa, like caste populations, show a high number of children ever born per mother of completed fertility. Quite a high masculinity in the secondary sex ratio, like other mongoloid population is noticed. The contribution of mortality component to the Total Index of Opportunity for Selection is more than that of the fertility component. Bhoksas conform to the general low range of net reproductive index, which is however greater than unity, suggesting that they are in a growth stage.

Marketing of Assisted Human Reproduction and the Indian State

OpenAIRE

Shree Mulay; Emily Gibson

2006-01-01

Shree Mulay and Emily Gibson examine the factors responsible for the phenomenal growth of the private fee-for-service health sector in India and the industry related to Assisted Human Reproduction, its negative effect on the public health sector as well as the feeble attempts by the Indian state to regulate this industry, and its implications for women's reproductive rights and health. Development (2006) 49, 84–93. doi:10.1057/palgrave.development.1100311

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

Nonconvex Model of Material Growth: Mathematical Theory

Science.gov (United States)

Ganghoffer, J. F.; Plotnikov, P. I.; Sokolowski, J.

2018-06-01

The model of volumetric material growth is introduced in the framework of finite elasticity. The new results obtained for the model are presented with complete proofs. The state variables include the deformations, temperature and the growth factor matrix function. The existence of global in time solutions for the quasistatic deformations boundary value problem coupled with the energy balance and the evolution of the growth factor is shown. The mathematical results can be applied to a wide class of growth models in mechanics and biology.

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.

Population Model with a Dynamic Food Supply

Science.gov (United States)

Dickman, Ronald; da Silva Nascimento, Jonas

2009-09-01

We propose a simple population model including the food supply as a dynamic variable. In the model, survival of an organism depends on a certain minimum rate of food consumption; a higher rate of consumption is required for reproduction. We investigate the stationary behavior under steady food input, and the transient behavior of growth and decay when food is present initially but is not replenished. Under a periodic food supply, the system exhibits period-doubling bifurcations and chaos in certain ranges of the reproduction rate. Bifurcations and chaos are favored by a slow reproduction rate and a long period of food-supply oscillation.

Integrating Growth Stage Deficit Irrigation into a Process Based Crop Model

Science.gov (United States)

Lopez, Jose R.; Winter, Jonathan M.; Elliott, Joshua; Ruane, Alex C.; Porter, Cheryl; Hoogenboom, Gerrit

2017-01-01

Current rates of agricultural water use are unsustainable in many regions, creating an urgent need to identify improved irrigation strategies for water limited areas. Crop models can be used to quantify plant water requirements, predict the impact of water shortages on yield, and calculate water productivity (WP) to link water availability and crop yields for economic analyses. Many simulations of crop growth and development, especially in regional and global assessments, rely on automatic irrigation algorithms to estimate irrigation dates and amounts. However, these algorithms are not well suited for water limited regions because they have simplistic irrigation rules, such as a single soil-moisture based threshold, and assume unlimited water. To address this constraint, a new modeling framework to simulate agricultural production in water limited areas was developed. The framework consists of a new automatic irrigation algorithm for the simulation of growth stage based deficit irrigation under limited seasonal water availability; and optimization of growth stage specific parameters. The new automatic irrigation algorithm was used to simulate maize and soybean in Gainesville, Florida, and first used to evaluate the sensitivity of maize and soybean simulations to irrigation at different growth stages and then to test the hypothesis that water productivity calculated using simplistic irrigation rules underestimates WP. In the first experiment, the effect of irrigating at specific growth stages on yield and irrigation water use efficiency (IWUE) in maize and soybean was evaluated. In the reproductive stages, IWUE tended to be higher than in the vegetative stages (e.g. IWUE was 18% higher than the well watered treatment when irrigating only during R3 in soybean), and when rainfall events were less frequent. In the second experiment, water productivity (WP) was significantly greater with optimized irrigation schedules compared to non-optimized irrigation schedules in

Testing R&D-Based Endogenous Growth Models

DEFF Research Database (Denmark)

Kruse-Andersen, Peter Kjær

2017-01-01

R&D-based growth models are tested using US data for the period 1953-2014. A general growth model is developed which nests the model varieties of interest. The model implies a cointegrating relationship between multifactor productivity, research intensity, and employment. This relationship...... is estimated using cointegrated VAR models. The results provide evidence against the widely used fully endogenous variety and in favor of the semi-endogenous variety. Forecasts based on the empirical estimates suggest that the slowdown in US productivity growth will continue. Particularly, the annual long...

Lifespan and reproduction in brain-specific miR-29-knockdown mouse.

Science.gov (United States)

Takeda, Toru; Tanabe, Hiroyuki

2016-03-18

The microRNA miR-29 is widely distributed and highly expressed in adult mouse brain during the mouse's lifetime. We recently created conditional mutant mice whose miR-29 was brain-specifically knocked down through overexpression of an antisense RNA transgene against miR-29. To explore a role for brain miR-29 in maximizing organismal fitness, we assessed somatic growth, reproduction, and lifespan in the miR-29-knockdown (KD) mice and their wild-type (WT) littermates. The KD mice were developmentally indistinguishable from WT mice with respect to gross morphology and physical activity. Fertility testing revealed that KD males were subfertile, whereas KD females were hyperfertile, only in terms of reproductive success, when compared to their gender-matched WT correspondents. Another phenotypic difference between KD and WT animals appeared in their lifespan data; KD males displayed an overall increasing tendency in post-reproductive survival relative to WT males. In contrast, KD females were prone to shorter lifespans than WT females. These results clarify that brain-targeted miR-29 knockdown affects both lifespan and reproduction in a gender-dependent manner, and moreover that the reciprocal responsiveness to the miR-29 knockdown between these two phenotypes in both genders closely follow life-course models based on the classical trade-off prediction wherein elaborate early-life energetic investment in reproduction entails accelerated late-life declines in survival, and vice versa. Thus, this study identified miR-29 as the first mammalian miRNA that is directly implicated in the lifetime trade-off between the two major fitness components, lifespan and reproduction. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Reproductive profiles and risk of breast cancer subtypes

DEFF Research Database (Denmark)

Brouckaert, Olivier; Rudolph, Anja; Laenen, Annouschka

2017-01-01

Background: Previous studies have shown that reproductive factors are differentially associated with breast cancer (BC) risk by subtypes. The aim of this study was to investigate associations between reproductive factors and BC subtypes, and whether these vary by age at diagnosis. Methods: We used...... pooled data on tumor markers (estrogen and progesterone receptor, human epidermal growth factor receptor-2 (HER2)) and reproductive risk factors (parity, age at first full-time pregnancy (FFTP) and age at menarche) from 28,095 patients with invasive BC from 34 studies participating in the Breast Cancer...... the risk for TNBC (OR = 0.78, CI 0.70-0.88, p diagnosis, whereas the association with luminal HER2-like BC was present only for early onset BC....

Effect of rosiglitazone on insulin resistance, growth factors, and reproductive disturbances in women with polycystic ovary syndrome.

Science.gov (United States)

Belli, Susana H; Graffigna, Mabel N; Oneto, Adriana; Otero, Patricia; Schurman, Leon; Levalle, Oscar A

2004-03-01

To evaluate the effects of rosiglitazone on insulin resistance, growth factors, and reproductive disturbances in women with polycystic ovary syndrome (PCOS). Prospective study. Women with PCOS attending as outpatients of the Endocrine Division, Hospital Durand, Buenos Aires. Twenty-four insulin-resistant women with PCOS. Hormonal evaluations and a standardized oral glucose tolerance test before and after a 3-month trial of 4 mg of rosiglitazone daily. Serum LH, FSH, T, IGF-1, IGFBP-1, IGFBP-3, leptin, 17alpha-hydroxyprogesterone, insulin, and glucose concentrations. The area under insulin curve (AUC-insulin), the HOMA index (insulin resistance), the QUICKI index (insulin sensitivity), and the beta-cell function were calculated. Body mass index (BMI) and the waist/hip ratio were evaluated. A significant decrease was observed in serum fasting insulin, AUC insulin, HOMA index, beta-cell function, IGF-1, LH, and waist/hip ratio. The QUICKI index and IGFBP-1 increased significantly. Serum sex hormone-binding globulin, androgens, leptin, IGFBP-3, and BMI remained unchanged. Twenty-two of 23 females had their menses restored, and three patients became pregnant. One patient was excluded because she became pregnant at the second month. Associated with the decrease in LH, rosiglitazone improved insulin-resistance parameters and normalized the menstrual cycle, which suggests that this drug could improve the endocrine-reproductive condition in insulin-resistant women with PCOS.

[World plan for reproductive autonomy and health].

Science.gov (United States)

Ospina, P

1994-06-01

The principal objective of the Third International Conference on Population and Development to be held in Cairo in 1994 is to achieve consensus on a Plan of Action to reinforce reproductive rights of individuals, who bear ultimate responsibility for slowing population growth. The Plan of Action should be adopted by all the peoples of the world in order to stabilize population growth during the next twenty years by means of programs to provide family planning and reproductive health services. The preliminary conference document incorporated recommendations and proposals of two preparatory committees, five regional conferences, six expert meetings, 109 countries, and over 400 nongovernmental organizations from around the world. At current rates of growth, the world's 5.7 billion inhabitants will increase to 9.1 billion by the year 2025, vastly increasing pressure on already limited resources and ecosystems. The central theme of the first World Population Conference in Bucharest in 1974 was the close relationship between population growth and socioeconomic development. The 1974 World Population Plan of Action stressed development of strategies to achieve a better quality of life and rapid socioeconomic development. Recommendations of the 1984 World Population Conference in Mexico remained centered on implementation of the Bucharest Plan of Action with a few additions. Although progress has been achieved in meeting the goals of the Bucharest Plan of Action, growth rates of some developing countries have actually increased. Poverty, unemployment, illiteracy, and discrimination against women are still obstacles to socioeconomic development, and contraceptive usage has not reached optimal levels. Urban migration remains excessive. Progress for many countries over the past decade has been directly related to increasing the access of women to health care and family planning. Themes related to women's status and rights will be incorporated in the 1994 Cairo Conference. The

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.

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.

Franchising Reproductive Health Services

Science.gov (United States)

Stephenson, Rob; Tsui, Amy Ong; Sulzbach, Sara; Bardsley, Phil; Bekele, Getachew; Giday, Tilahun; Ahmed, Rehana; Gopalkrishnan, Gopi; Feyesitan, Bamikale

2004-01-01

Objectives Networks of franchised health establishments, providing a standardized set of services, are being implemented in developing countries. This article examines associations between franchise membership and family planning and reproductive health outcomes for both the member provider and the client. Methods Regression models are fitted examining associations between franchise membership and family planning and reproductive health outcomes at the service provider and client levels in three settings. Results Franchising has a positive association with both general and family planning client volumes, and the number of family planning brands available. Similar associations with franchise membership are not found for reproductive health service outcomes. In some settings, client satisfaction is higher at franchised than other types of health establishments, although the association between franchise membership and client outcomes varies across the settings. Conclusions Franchise membership has apparent benefits for both the provider and the client, providing an opportunity to expand access to reproductive health services, although greater attention is needed to shift the focus from family planning to a broader reproductive health context. PMID:15544644

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

Population dynamics of Salpa thompsoni near the Antarctic Peninsula: Growth rates and interannual variations in reproductive activity (1993-2009)

Science.gov (United States)

Loeb, V. J.; Santora, J. A.

2012-04-01

The salp Salpa thompsoni has exhibited increased abundance in high latitude portions of the Southern Ocean in recent decades and is now frequently the numerically dominant zooplankton taxon in the Antarctic Peninsula region. The abundance increase of this species in high latitude waters is believed related to ocean warming. Due to its continuous filter feeding and production of dense rapidly sinking fecal pellets S. thompsoni is considered to be an important link in the export of particulate carbon from the surface waters. Hence basic information on the life history of this component of the Antarctic marine ecosystem is essential for assessing its impact given continued climate warming. Here we cover various aspects of the life history of S. thompsoni collected in the north Antarctic Peninsula during annual austral summer surveys of the US Antarctic Marine Living Resources (AMLR) Program between 1993 and 2009. We focus on seasonal and interannual variations in the size composition and abundance of the aggregate (sexual) and solitary (asexual) stages. This information is valuable for refining components of Southern Ocean food web models that explicitly deal with size-structured and life history information on zooplankton. Intraseasonal changes in length-frequency distribution of both stages are used to estimate their growth rates. These average 0.40 mm day-1 for aggregates and 0.23 mm day-1 for solitaries; together these represent ∼7 week and ∼7.5 month generation times, respectively, and a 9 month life cycle (i.e., onset of aggregate production year 1 to aggregate production year 2). Based on the maximum lengths typically found during January-March, the life spans of the aggregate and solitary stages can reach at least ∼5 and ∼15 months, respectively. Length-frequency distributions each year reflect interannual differences in timing of the initiation and peak reproductive output. Interannual differences in the abundance of total salps and proportions of the

Kinetic Model of Growth of Arthropoda Populations

Science.gov (United States)

Ershov, Yu. A.; Kuznetsov, M. A.

2018-05-01

Kinetic equations were derived for calculating the growth of crustacean populations ( Crustacea) based on the biological growth model suggested earlier using shrimp ( Caridea) populations as an example. The development cycle of successive stages for populations can be represented in the form of quasi-chemical equations. The kinetic equations that describe the development cycle of crustaceans allow quantitative prediction of the development of populations depending on conditions. In contrast to extrapolation-simulation models, in the developed kinetic model of biological growth the kinetic parameters are the experimental characteristics of population growth. Verification and parametric identification of the developed model on the basis of the experimental data showed agreement with experiment within the error of the measurement technique.

Long-term fiscal implications of funding assisted reproduction: a generational accounting model for Spain

Directory of Open Access Journals (Sweden)

R. Matorras

2015-12-01

Full Text Available The aim of this study was to assess the lifetime economic benefits of assisted reproduction in Spain by calculating the return on this investment. We developed a generational accounting model that simulates the flow of taxes paid by the individual, minus direct government transfers received over the individual’s lifetime. The difference between discounted transfers and taxes minus the cost of either IVF or artificial insemination (AI equals the net fiscal contribution (NFC of a child conceived through assisted reproduction. We conducted sensitivity analysis to test the robustness of our results under various macroeconomic scenarios. A child conceived through assisted reproduction would contribute €370,482 in net taxes to the Spanish Treasury and would receive €275,972 in transfers over their lifetime. Taking into account that only 75% of assisted reproduction pregnancies are successful, the NFC was estimated at €66,709 for IVF-conceived children and €67,253 for AI-conceived children. The return on investment for each euro invested was €15.98 for IVF and €18.53 for AI. The long-term NFC of a child conceived through assisted reproduction could range from €466,379 to €-9,529 (IVF and from €466,923 to €-8,985 (AI. The return on investment would vary between €-2.28 and €111.75 (IVF, and €-2.48 and €128.66 (AI for each euro invested. The break-even point at which the financial position would begin to favour the Spanish Treasury ranges between 29 and 41 years of age. Investment in assisted reproductive techniques may lead to positive discounted future fiscal revenue, notwithstanding its beneficial psychological effect for infertile couples in Spain.

Fungal Morphogenesis, from the Polarized Growth of Hyphae to Complex Reproduction and Infection Structures.

Science.gov (United States)

Riquelme, Meritxell; Aguirre, Jesús; Bartnicki-García, Salomon; Braus, Gerhard H; Feldbrügge, Michael; Fleig, Ursula; Hansberg, Wilhelm; Herrera-Estrella, Alfredo; Kämper, Jörg; Kück, Ulrich; Mouriño-Pérez, Rosa R; Takeshita, Norio; Fischer, Reinhard

2018-06-01

Filamentous fungi constitute a large group of eukaryotic microorganisms that grow by forming simple tube-like hyphae that are capable of differentiating into more-complex morphological structures and distinct cell types. Hyphae form filamentous networks by extending at their tips while branching in subapical regions. Rapid tip elongation requires massive membrane insertion and extension of the rigid chitin-containing cell wall. This process is sustained by a continuous flow of secretory vesicles that depends on the coordinated action of the microtubule and actin cytoskeletons and the corresponding motors and associated proteins. Vesicles transport cell wall-synthesizing enzymes and accumulate in a special structure, the Spitzenkörper, before traveling further and fusing with the tip membrane. The place of vesicle fusion and growth direction are enabled and defined by the position of the Spitzenkörper, the so-called cell end markers, and other proteins involved in the exocytic process. Also important for tip extension is membrane recycling by endocytosis via early endosomes, which function as multipurpose transport vehicles for mRNA, septins, ribosomes, and peroxisomes. Cell integrity, hyphal branching, and morphogenesis are all processes that are largely dependent on vesicle and cytoskeleton dynamics. When hyphae differentiate structures for asexual or sexual reproduction or to mediate interspecies interactions, the hyphal basic cellular machinery may be reprogrammed through the synthesis of new proteins and/or the modification of protein activity. Although some transcriptional networks involved in such reprogramming of hyphae are well studied in several model filamentous fungi, clear connections between these networks and known determinants of hyphal morphogenesis are yet to be established. Copyright © 2018 American Society for Microbiology.

Reproductive and metabolic phenotype of a mouse model of PCOS

NARCIS (Netherlands)

E. Leonie (E.); A.F. van Houten (A.); P. Kramer (Piet); A. McLuskey; B. Karels (Bas); A.P.N. Themmen (Axel); J.A. Visser (Jenny)

2012-01-01

textabstractPolycystic ovary syndrome (PCOS), the most common endocrine disorder in women in their reproductive age, is characterized by both reproductive and metabolic features. Recent studies in human, nonhuman primates, and sheep suggest that hyperandrogenism plays an important role in the

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

Economic consequences of reproductive performance in dairy cattle

NARCIS (Netherlands)

Inchaisri, C.; Jorritsma, R.; Vos, P.L.A.M.; Weijden, van der G.C.; Hogeveen, H.

2010-01-01

The net economic value of reproductive efficiency in dairy cattle was estimated using a stochastic dynamic simulation model. The objective was to compare the economic consequences of reproductive performance scenarios (“average” and “poor”) of a cow having a good reproductive performance and to

Human evolution, life history theory, and the end of biological reproduction.

Science.gov (United States)

Last, Cadell

2014-01-01

Throughout primate history there have been three major life history transitions towards increasingly delayed sexual maturation and biological reproduction, as well as towards extended life expectancy. Monkeys reproduce later and live longer than do prosimians, apes reproduce later and live longer than do monkeys, and humans reproduce later and live longer than do apes. These life history transitions are connected to increased encephalization. During the last life history transition from apes to humans, increased encephalization co-evolved with increased dependence on cultural knowledge for energy acquisition. This led to a dramatic pressure for more energy investment in growth over current biological reproduction. Since the industrial revolution socioeconomic development has led to even more energy being devoted to growth over current biological reproduction. I propose that this is the beginning of an ongoing fourth major primate life history transition towards completely delayed biological reproduction and an extension of the evolved human life expectancy. I argue that the only fundamental difference between this primate life history transition and previous life history transitions is that this transition is being driven solely by cultural evolution, which may suggest some deeper evolutionary transition away from biological evolution is already in the process of occurring.

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.

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

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.

Growth rate, population entropy, and perturbation theory.

OpenAIRE

Demetrius, L.

1989-01-01

This paper is concerned with the connection between two classes of population variables: measures of population growth rate—the Malthusian parameter, the net reproduction rate, the gross reproduction rate, and the mean life expectancy; and measures of demographic heterogeneity—population entropy. It is shown that the entropy functions predict the response of the growth rate parameters to perturbations in the age-specific fecundity and mortality schedule. These results are invoked to introduce...

Mathematical model of reproductive death of irradiated eukaryotic cells, which considers saturation of DNA reparation system

International Nuclear Information System (INIS)

Knyigavko, V.G.; Ponomarenko, N.S.; Meshcheryakova, O.P.; Protasenya, S.Yu.

2009-01-01

A mathematical model of the processes determining reproductive death of the exposed cells was built. The model takes into account the phenomenon of saturation of the system of DNA radiation lesion reparation and structural functional peculiarities of chromatin structure in eukaryotes. The problem of assessment of the model parameters using experimental data was discussed.

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...

Client satisfaction with reproductive health-care quality: integrating business approaches to modeling and measurement.

Science.gov (United States)

Alden, Dana L; Do, Mai Hoa; Bhawuk, Dharm

2004-12-01

Health-care managers are increasingly interested in client perceptions of clinic service quality and satisfaction. While tremendous progress has occurred, additional perspectives on the conceptualization, modeling and measurement of these constructs may further assist health-care managers seeking to provide high-quality care. To that end, this study draws on theories from business and health to develop an integrated model featuring antecedents to and consequences of reproductive health-care client satisfaction. In addition to developing a new model, this study contributes by testing how well Western-based theories of client satisfaction hold in a developing, Asian country. Applied to urban, reproductive health clinic users in Hanoi, Vietnam, test results suggest that hypothesized antecedents such as pre-visit expectations, perceived clinic performance and how much performance exceeds expectations impact client satisfaction. However, the relative importance of these predictors appears to vary depending on a client's level of service-related experience. Finally, higher levels of client satisfaction are positively related to future clinic use intentions. This study demonstrates the value of: (1) incorporating theoretical perspectives from multiple disciplines to model processes underlying health-care satisfaction and (2) field testing those models before implementation. It also furthers research designed to provide health-care managers with actionable measures of the complex processes related to their clients' satisfaction.

Semi-determinate growth habit adjusts the vegetative-to-reproductive balance and increases productivity and water-use efficiency in tomato (Solanum lycopersicum).

Science.gov (United States)

Vicente, Mateus Henrique; Zsögön, Agustin; de Sá, Ariadne Felicio Lopo; Ribeiro, Rafael V; Peres, Lázaro E P

2015-04-01

Tomato (Solanum lycopersicum) shows three growth habits: determinate, indeterminate and semi-determinate. These are controlled mainly by allelic variation in the self-pruning (SP) gene family, which also includes the "florigen" gene single flower TRUSS (SFT). Determinate cultivars have synchronized flower and fruit production, which allows mechanical harvesting in the tomato processing industry, whereas indeterminate ones have more vegetative growth with continuous flower and fruit formation, being thus preferred for fresh market tomato production. The semi-determinate growth habit is poorly understood, although there are indications that it combines advantages of determinate and indeterminate growth. Here, we used near-isogenic lines (NILs) in the cultivar Micro-Tom (MT) with different growth habit to characterize semi-determinate growth and to determine its impact on developmental and productivity traits. We show that semi-determinate genotypes are equivalent to determinate ones with extended vegetative growth, which in turn impacts shoot height, number of leaves and either stem diameter or internode length. Semi-determinate plants also tend to increase the highly relevant agronomic parameter Brix × ripe yield (BRY). Water-use efficiency (WUE), evaluated either directly as dry mass produced per amount of water transpired or indirectly through C isotope discrimination, was higher in semi-determinate genotypes. We also provide evidence that the increases in BRY in semi-determinate genotypes are a consequence of an improved balance between vegetative and reproductive growth, a mechanism analogous to the conversion of the overly vegetative tall cereal varieties into well-balanced semi-dwarf ones used in the Green Revolution. Copyright © 2015 Elsevier GmbH. All rights reserved.

Ethics and regulation of inter-country medically assisted reproduction: a call for action

OpenAIRE

Shalev, Carmel; Moreno, Adi; Eyal, Hedva; Leibel, Michal; Schuz, Rhona; Eldar-Geva, Talia

2016-01-01

The proliferation of medically assisted reproduction (MAR) for the treatment of infertility has brought benefit to many individuals around the world. But infertility and its treatment continue to be a cause of suffering, and over the past decade, there has been a steady growth in a new global market of inter-country medically assisted reproduction (IMAR) involving ?third-party? individuals acting as surrogate mothers and gamete donors in reproductive collaborations for the benefit of other in...

Graphene growth process modeling: a physical-statistical approach

Science.gov (United States)

Wu, Jian; Huang, Qiang

2014-09-01

As a zero-band semiconductor, graphene is an attractive material for a wide variety of applications such as optoelectronics. Among various techniques developed for graphene synthesis, chemical vapor deposition on copper foils shows high potential for producing few-layer and large-area graphene. Since fabrication of high-quality graphene sheets requires the understanding of growth mechanisms, and methods of characterization and control of grain size of graphene flakes, analytical modeling of graphene growth process is therefore essential for controlled fabrication. The graphene growth process starts with randomly nucleated islands that gradually develop into complex shapes, grow in size, and eventually connect together to cover the copper foil. To model this complex process, we develop a physical-statistical approach under the assumption of self-similarity during graphene growth. The growth kinetics is uncovered by separating island shapes from area growth rate. We propose to characterize the area growth velocity using a confined exponential model, which not only has clear physical explanation, but also fits the real data well. For the shape modeling, we develop a parametric shape model which can be well explained by the angular-dependent growth rate. This work can provide useful information for the control and optimization of graphene growth process on Cu foil.

Prediction of the lifetime productive and reproductive performance of Holstein cows managed for different lactation durations, using a model of lifetime nutrient partitioning

DEFF Research Database (Denmark)

Gaillard, Charlotte; Martin, O; Blavy, P

2016-01-01

The GARUNS model is a lifetime performance model taking into account the changing physiological priorities of an animal during its life and through repeated reproduction cycles. This dynamic and stochastic model has been previously used to predict the productive and reproductive performance...... of various genotypes of cows across feeding systems. In the present paper, we used this model to predict the lifetime productive and reproductive performance of Holstein cows for different lactation durations, with the aim of determining the lifetime scenario that optimizes cows' performance defined...... by lifetime efficiency (ratio of total milk energy yield to total energy intake) and pregnancy rate. To evaluate the model, data from a 16-mo extended lactation experiment on Holstein cows were used. Generally, the model could consistently fit body weight, milk yield, and milk components of these cows...

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.

Modelling predicts that tolerance to drought during reproductive development will be required for high yield potential and stability of wheat in Europe

Science.gov (United States)

Semenov, Mikhail A.; Stratonovitch, Pierre; Paul, Matthew J.

2017-04-01

Short periods of extreme weather, such as a spell of high temperature or drought during a sensitive stage of development, could result in substantial yield losses due to reduction in grain number and grain size. In a modelling study (Stratonovitch & Semenov 2015), heat tolerance around flowering in wheat was identified as a key trait for increased yield potential in Europe under climate change. Ji et all (Ji et al. 2010) demonstrated cultivar specific responses of yield to drought stress around flowering in wheat. They hypothesised that carbohydrate supply to anthers may be the key in maintaining pollen fertility and grain number in wheat. It was shown in (Nuccio et al. 2015) that genetically modified varieties of maize that increase the concentration of sucrose in ear spikelets, performed better under non-drought and drought conditions in field experiments. The objective of this modelling study was to assess potential benefits of tolerance to drought during reproductive development for wheat yield potential and yield stability across Europe. We used the Sirius wheat model to optimise wheat ideotypes for 2050 (HadGEM2, RCP8.5) climate scenarios at selected European sites. Eight cultivar parameters were optimised to maximise mean yields, including parameters controlling phenology, canopy growth and water limitation. At those sites where water could be limited, ideotypes sensitive to drought produced substantially lower mean yields and higher yield variability compare with tolerant ideotypes. Therefore, tolerance to drought during reproductive development is likely to be required for wheat cultivars optimised for the future climate in Europe in order to achieve high yield potential and yield stability.

Androgen action in the masculinization programming window and development of male reproductive organs.

Science.gov (United States)

Macleod, D J; Sharpe, R M; Welsh, M; Fisken, M; Scott, H M; Hutchison, G R; Drake, A J; van den Driesche, S

2010-04-01

We have shown previously that deficient androgen action within a masculinization programming window (MPW; e15.5-e18.5 in rats) is important in the origin of male reproductive disorders and in programming male reproductive organ size, but that androgen action postnatally may be important to achieve this size. To further investigate importance of the MPW, we used two rat models, in which foetal androgen production or action was impaired during the MPW by exposing in utero to either di(n-butyl) phthalate (DBP) or to flutamide. Reduced anogenital distance (AGD) was used as a monitor of androgen production/action during the MPW. Offspring were evaluated in early puberty (Pnd25) to establish if reproductive organ size was altered. The testes, penis, ventral prostate (VP) and seminal vesicles (SV) were weighed and penis length measured. Both DBP and flutamide exposure in the MPW significantly reduced penis, VP and SV size along with AGD at Pnd25; AGD and organ size were highly correlated. In DBP-, but not flutamide-, exposed animals, testis weight was also reduced and correlated with AGD. Intratesticular testosterone was also measured in control and DBP-exposed males during (e17.5) or after (e21.5) the MPW and related to AGD at e21.5. To evaluate the importance of postnatal androgen action in reproductive organ growth, the effect of combinations of prenatal and postnatal maternal treatments on AGD and penis size at Pnd25 was evaluated. In prenatally DBP-exposed animals, further postnatal exposure to either DBP or flutamide significantly reduced AGD and penis size in comparison with prenatal DBP exposure alone. In comparison, rats exposed postnatally to testosterone propionate after prenatal vehicle-exposure showed considerable increase in these parameters vs. controls. In conclusion, we show that the size of all male reproductive organs is programmed by androgen exposure in the MPW, but that growth towards this size is dependent on androgen action postnatally.

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.

A test of reproductive power in snakes.

Science.gov (United States)

Boback, Scott M; Guyer, Craig

2008-05-01

Reproductive power is a contentious concept among ecologists, and the model has been criticized on theoretical and empirical grounds. Despite these criticisms, the model has successfully predicted the modal (optimal) size in three large taxonomic groups and the shape of the body size distribution in two of these groups. We tested the reproductive power model on snakes, a group that differs markedly in physiology, foraging ecology, and body shape from the endothermic groups upon which the model was derived. Using detailed field data from the published literature, snake-specific constants associated with reproductive power were determined using allometric relationships of energy invested annually in egg production and population productivity. The resultant model accurately predicted the mode and left side of the size distribution for snakes but failed to predict the right side of that distribution. If the model correctly describes what is possible in snakes, observed size diversity is limited, especially in the largest size classes.

Effects of two polybrominated diphenyl ethers (BDE-47, BDE-209) on the swimming behavior, population growth and reproduction of the rotifer Brachionus plicatilis.

Science.gov (United States)

Sha, Jingjing; Wang, You; Lv, Jianxia; Wang, Hong; Chen, Hongmei; Qi, Leilei; Tang, Xuexi

2015-02-01

Polybrominated diphenyl ethers (PBDEs) are new kinds of persistent organic pollutants (POPs) and their potential threats to the equilibrium and sustainability of marine ecosystems have raised worldwide concerns. Here, two kinds of PBDEs, tetra-BDE (BDE-47) and deca-BDE (BDE-209) were applied, and their toxic effects on the swimming behavior, population growth and reproduction of Brachionus plicatilis were investigated. The results showed that: (1) The actual concentrations of BDE-47 and -209 in the seawater phase measured by GC-MS (Gas Chromatography-Mass Spectrometer) were much lower than their nominal concentrations. (2) In accordance with the 24-hr acute tests, BDE-209 did not show any obvious swimming inhibition to rotifers, but a good correlation did exist between the swimming inhibition rate and BDE-47 concentration suggesting that BDE-47 is more toxic than BDE-209. (3) Both BDE-47 and -209 had a significant influence on the population growth and reproduction parameters of B. plicatilis including the population growth rate, the ratio of ovigerous females/non-ovigerous females (OF/NOF), the ratio of mictic females/amictic females (MF/AF), resting egg production and the mictic rate, which indicate that these parameters in B. plicatilis population were suitable for monitoring and assessing PBDEs. Our results suggest that BDE-47 and -209 are not acute lethal toxicants and may pose a low risk to marine rotifers at environmental concentrations for short-term exposure. They also accumulate differently into rotifers. Further research data are needed to understand the mechanisms responsible for the effects caused by PBDEs and to assess their risks accurately. Copyright © 2014. Published by Elsevier B.V.

effects of electromagnetic radiations on the male reproductive system

African Journals Online (AJOL)

2018-02-28

Feb 28, 2018 ... growth, differentiation, proliferation and stress .... heat up the water if is of sufficient power, by way .... stress in male reproductive physiology. .... W., Kas, G 1998 Conspicuous behavioural abnormalities in a dairy cow herd near.

Steroidogenic versus Metabolic Programming of Reproductive Neuroendocrine, Ovarian and Metabolic Dysfunctions.

Science.gov (United States)

Cardoso, Rodolfo C; Puttabyatappa, Muraly; Padmanabhan, Vasantha

2015-01-01

The susceptibility of the reproductive system to early exposure to steroid hormones has become a major concern in our modern societies. Human fetuses are at risk of abnormal programming via exposure to endocrine disrupting chemicals, inadvertent use of contraceptive pills during pregnancy, as well as from excess exposure to steroids due to disease states. Animal models provide an unparalleled resource to understand the developmental origin of diseases. In female sheep, prenatal exposure to testosterone excess results in an array of adult reproductive disorders that recapitulate those seen in women with polycystic ovary syndrome (PCOS), including disrupted neuroendocrine feedback mechanisms, increased pituitary sensitivity to gonadotropin-releasing hormone, luteinizing hormone excess, functional hyperandrogenism, and multifollicular ovarian morphology culminating in early reproductive failure. Prenatal testosterone treatment also leads to fetal growth retardation, insulin resistance, and hypertension. Mounting evidence suggests that developmental exposure to an improper steroidal/metabolic environment may mediate the programming of adult disorders in prenatal testosterone-treated females, and these defects are maintained or amplified by the postnatal sex steroid and metabolic milieu. This review addresses the steroidal and metabolic contributions to the development and maintenance of the PCOS phenotype in the prenatal testosterone-treated sheep model, including the effects of prenatal and postnatal treatment with an androgen antagonist or insulin sensitizer as potential strategies to prevent/ameliorate these dysfunctions. Insights obtained from these intervention strategies on the mechanisms underlying these defects are likely to have translational relevance to human PCOS. © 2015 S. Karger AG, Basel.

ROLE OF SEROTONIN IN FISH REPRODUCTION

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Parvathy ePrasad

2015-06-01

Full Text Available The neuroendocrine mechanism regulates reproduction through the hypothalamo-pituitary-gonadal (HPG axis which is evolutionarily conserved in vertebrates. The HPG axis is regulated by a variety of internal as well as external factors. Serotonin, a monoamine neurotransmitter, is involved in a wide range of reproductive functions. In mammals, serotonin regulates sexual behaviours, gonadotropin release and gonadotropin-release hormone (GnRH secretion. However, the serotonin system in teleost may play unique role in the control of reproduction as the mechanism of reproductive control in teleosts is not always the same as in the mammalian models. In fish, the serotonin system is also regulated by natural environmental factors as well as chemical substances. In particular, selective serotonin reuptake inhibitors (SSRIs are commonly detected as pharmaceutical contaminants in the natural environment. Those factors may influence fish reproductive functions via the serotonin system. This review summarizes the functional significance of serotonin in the teleosts reproduction.

Naloxone affects reproductive system in a rat model with polycystic features

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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.

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

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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

IV. Crossbred reproduction and constant slaughter mass

African Journals Online (AJOL)

Higher reproduction and lower replacement rates lead to a higher proportion of terminally crossbred offspring to sell. Substantial improvement in herd .... growth below the knee and hock is completed at birth. In cattle and sheep there is hope ... reported highly significant total heterosis for birth mass in the. Angus X Hereford ...

Modelling asymmetric growth in crowded plant communities

DEFF Research Database (Denmark)

Damgaard, Christian

2010-01-01

A class of models that may be used to quantify the effect of size-asymmetric competition in crowded plant communities by estimating a community specific degree of size-asymmetric growth for each species in the community is suggested. The model consists of two parts: an individual size......-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....

A new model for simulating growth in fish

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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.

Ultrasonographic evaluation of reproductive tract measures and fat thickness traits in pre-pubertal Nellore heifers

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Fabio Morato Monteiro

2012-02-01

Full Text Available The aim of this study was to evaluate the relationship between reproductive tract and fat thickness measures obtained by ultrasound in prepubertal Nellore heifers. A total of 128 Nellore heifers born in 2006 and 2007 were submitted to ultrasound evaluations (13, 16, 19 and 22 months of age of reproductive tract measures and fat thickness traits. These animals were from a selection experiment (NeC: control line, and NeS: selection line for yearling weight started in 1981. Mean values of ovary area, height of the right uterine horn (HU, maximum follicular diameter (FOL, backfat thickness (BF, rump fat thickness (RF, and body condition score were analyzed. Repeated records were modeled using the PROC MIXED procedure (SAS, fitting a model that included the selection line, year of birth, measurement as fixed effects, and interactions. Body weight differed between the selected (281.48 kg and control (210.51 kg lines. Only the least square means of FOL were lower in the NeC line compared to the NeS line (P < 0.05, although the difference in mean HU between the two lines was of only borderline significance (P = 0.06. The rate of growth for the three reproductive traits was similar in the two lines. Simple and residual correlations between the reproductive and subcutaneous fat traits ranged from low to medium. The highest correlations were observed between HU and RF (Pearson correlation = 0.71 and residual correlation = 0.34. The current results are consistent with the literature, indicating that fat thickness traits are not good predictors of prepubertal reproductive traits in heifers. Further studies are necessary to clarify the relationship between reproduction and body fat in Nellore heifers.

Modeling Population Growth and Extinction

Science.gov (United States)

Gordon, Sheldon P.

2009-01-01

The exponential growth model and the logistic model typically introduced in the mathematics curriculum presume that a population grows exclusively. In reality, species can also die out and more sophisticated models that take the possibility of extinction into account are needed. In this article, two extensions of the logistic model are considered,…

Clonal growth and plant species abundance.

Science.gov (United States)

Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

2014-08-01

Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf-height-seed) traits and by actual performance in the botanical garden. Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area - height - seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially underlying clonal growth effects on abundance. Garden

Modeling of Hybrid Growth Wastewater Bio-reactor

International Nuclear Information System (INIS)

EI Nashaei, S.; Garhyan, P.; Prasad, P.; Abdel Halim, H.S.; Ibrahim, G.

2004-01-01

The attached/suspended growth mixed reactors are considered one of the recently tried approaches to improve the performance of the biological treatment by increasing the volume of the accumulated biomass in terms of attached growth as well as suspended growth. Moreover, the domestic WW can be easily mixed with a high strength non-hazardous industrial wastewater and treated together in these bio-reactors if the need arises. Modeling of Hybrid hybrid growth wastewater reactor addresses the need of understanding the rational of such system in order to achieve better design and operation parameters. This paper aims at developing a heterogeneous mathematical model for hybrid growth system considering the effect of diffusion, external mass transfer, and power input to the system in a rational manner. The model will be based on distinguishing between liquid/solid phase (bio-film and bio-floc). This model would be a step ahead to the fine tuning the design of hybrid systems based on the experimental data of a pilot plant to be implemented in near future

Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size

Science.gov (United States)

King, Richard B.

2016-01-01

Body size, and, by extension, growth has impacts on physiology, survival, attainment of sexual maturity, fecundity, generation time, and population dynamics, especially in ectotherm animals that often exhibit extensive growth following attainment of sexual maturity. Frequently, growth is analyzed at the population level, providing useful population mean growth parameters but ignoring individual variation that is also of ecological and evolutionary significance. Our long-term study of Lake Erie Watersnakes, Nerodia sipedon insularum, provides data sufficient for a detailed analysis of population and individual growth. We describe population mean growth separately for males and females based on size of known age individuals (847 captures of 769 males, 748 captures of 684 females) and annual growth increments of individuals of unknown age (1,152 males, 730 females). We characterize individual variation in asymptotic size based on repeated measurements of 69 males and 71 females that were each captured in five to nine different years. The most striking result of our analyses is that asymptotic size varies dramatically among individuals, ranging from 631–820 mm snout-vent length in males and from 835–1125 mm in females. Because female fecundity increases with increasing body size, we explore the impact of individual variation in asymptotic size on lifetime reproductive success using a range of realistic estimates of annual survival. When all females commence reproduction at the same age, lifetime reproductive success is greatest for females with greater asymptotic size regardless of annual survival. But when reproduction is delayed in females with greater asymptotic size, lifetime reproductive success is greatest for females with lower asymptotic size when annual survival is low. Possible causes of individual variation in asymptotic size, including individual- and cohort-specific variation in size at birth and early growth, warrant further investigation. PMID

Size Matters: Individual Variation in Ectotherm Growth and Asymptotic Size.

Directory of Open Access Journals (Sweden)

Richard B King

Full Text Available Body size, and, by extension, growth has impacts on physiology, survival, attainment of sexual maturity, fecundity, generation time, and population dynamics, especially in ectotherm animals that often exhibit extensive growth following attainment of sexual maturity. Frequently, growth is analyzed at the population level, providing useful population mean growth parameters but ignoring individual variation that is also of ecological and evolutionary significance. Our long-term study of Lake Erie Watersnakes, Nerodia sipedon insularum, provides data sufficient for a detailed analysis of population and individual growth. We describe population mean growth separately for males and females based on size of known age individuals (847 captures of 769 males, 748 captures of 684 females and annual growth increments of individuals of unknown age (1,152 males, 730 females. We characterize individual variation in asymptotic size based on repeated measurements of 69 males and 71 females that were each captured in five to nine different years. The most striking result of our analyses is that asymptotic size varies dramatically among individuals, ranging from 631-820 mm snout-vent length in males and from 835-1125 mm in females. Because female fecundity increases with increasing body size, we explore the impact of individual variation in asymptotic size on lifetime reproductive success using a range of realistic estimates of annual survival. When all females commence reproduction at the same age, lifetime reproductive success is greatest for females with greater asymptotic size regardless of annual survival. But when reproduction is delayed in females with greater asymptotic size, lifetime reproductive success is greatest for females with lower asymptotic size when annual survival is low. Possible causes of individual variation in asymptotic size, including individual- and cohort-specific variation in size at birth and early growth, warrant further

Economic Growth Models Transition

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Coralia Angelescu

2006-03-01

Full Text Available The transitional recession in countries of Eastern Europe has been much longer than expected. The legacy and recent policy mistakes have both contributed to the slow progress. As structural reforms and gradual institution building have taken hold, the post-socialist economics have started to recover, with some leading countries building momentum toward faster growth. There is a possibility that in wider context of globalization several of these emerging market economies will be able to catch up with the more advanced industrial economies in a matter of one or two generations. Over the past few years, most candidate countries have made progress in the transition to a competitive market economy, macroeconomic stabilization and structural reform. However their income levels have remained far below those in the Member States. Measured by per capita income in purchasing power standards, there has been a very limited amount of catching up over the past fourteen years. Prior, the distinctions between Solow-Swan model and endogenous growth model. The interdependence between transition and integration are stated in this study. Finally, some measures of macroeconomic policy for sustainable growth are proposed in correlation with real macroeconomic situation of the Romanian economy. Our study would be considered the real convergence for the Romanian economy and the recommendations for the adequate policies to achieve a fast real convergence and sustainable growth.

Economic Growth Models Transition

Directory of Open Access Journals (Sweden)

Coralia Angelescu

2006-01-01

Full Text Available The transitional recession in countries of Eastern Europe has been much longer than expected. The legacy and recent policy mistakes have both contributed to the slow progress. As structural reforms and gradual institution building have taken hold, the post-socialist economics have started to recover, with some leading countries building momentum toward faster growth. There is a possibility that in wider context of globalization several of these emerging market economies will be able to catch up with the more advanced industrial economies in a matter of one or two generations. Over the past few years, most candidate countries have made progress in the transition to a competitive market economy, macroeconomic stabilization and structural reform. However their income levels have remained far below those in the Member States. Measured by per capita income in purchasing power standards, there has been a very limited amount of catching up over the past fourteen years. Prior, the distinctions between Solow-Swan model and endogenous growth model. The interdependence between transition and integration are stated in this study. Finally, some measures of macroeconomic policy for sustainable growth are proposed in correlation with real macroeconomic situation of the Romanian economy. Our study would be considered the real convergence for the Romanian economy and the recommendations for the adequate policies to achieve a fast real convergence and sustainable growth.

Recent advances in modelling creep crack growth

International Nuclear Information System (INIS)

Riedel, H.

1988-08-01

At the time of the previous International Conference on Fracture, the C* integral had long been recognized as a promising load parameter for correlating crack growth rates in creep-ductile materials. The measured crack growth rates as a function of C* and of the temperature could be understood on the basis of micromechanical models. The distinction between C*-controlled and K I -controlled creep crack growth had been clarified and first attempts had been made to describe creep crack growth in the transient regime between elastic behavior and steady-state creep. This paper describes the progress in describing transient crack growth including the effect of primary creep. The effect of crack-tip geometry changes by blunting and by crack growth on the crack-tip fields and on the validity of C* is analyzed by idealizing the growing-crack geometry by a sharp notch and using recent solutions for the notch-tip fields. A few new three-dimensional calculations of C* are cited and important theoretical points are emphasized regarding the three-dimensional fields at crack tips. Finally, creep crack growth is described by continuum-damage models for which similarity solutions can be obtained. Crack growth under small-scale creep conditions turns out to be difficult to understand. Slightly different models yield very different crack growth rates. (orig.) With 4 figs

The Ewe’s Reproductive Performance, Growth Rate and Carcass Quality of Lambs Kept in a Barn vs Those Kept under an Overhead Shelter

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Ewa Kuźnicka

2013-02-01

Full Text Available A herd of polish lowland local sheep was divided into two equal groups: the first group was kept under an overhead shelter, and the second group was kept in a warm barn. The effect of maintenance on ewe’s reproductive performance, survival as well as the growth rate of lambs, and their carcasses quality was investigated. The lack of differences in fertility and prolificacy of ewes as well as in the survival and growth rate between the groups confirmed a good adaptation of Żelaźnieńska sheep to low temperature. Harsh environmental conditions did not cause a significant decrease of the body weight growth; however, they brought in an (insignificant reduction of subcutaneous fat thickness and meatiness of the loin part of a lamb’s body. The fat content of carcasses obtained from lambs reared under the overhead shelter was significantly lower, with no differences of meat and bones contribution between the groups.

Progestogen treatments for cycle management in a sheep model of assisted conception affect the growth patterns, the expression of luteinizing hormone receptors, and the progesterone secretion of induced corpora lutea.

Science.gov (United States)

Letelier, Claudia; García-Fernández, Rosa Ana; Contreras-Solis, Ignacio; Sanchez, María Angeles; Garcia-Palencia, Pilar; Sanchez, Belen; Gonzalez-Bulnes, Antonio; Flores, Juana María

2010-03-01

To determine, in a sheep model, the effect of a short-term progestative treatment on growth dynamics and functionality of induced corpora lutea. Observational, model study. Public university. Sixty adult female sheep. Synchronization and induction of ovulation with progestogens and prostaglandin analogues; ovarian ultrasonography, blood sampling, and ovariectomy. Determination of pituitary function and morphologic characteristics, expression of luteinizing hormone (LH) receptors, and progesterone secretion of corpora lutea. The use of progestative pretreatments for assisted conception affect the growth patterns, the expression of LH receptors, and the progesterone secretion of induced corpora lutea. The current study indicates, in a sheep model, the existence of deleterious effects from progestogens on functionality of induced corpora lutea. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Reproduction and growth of the painted comber Serranus scriba (Serranidae) of the Marine Reserve of Lanzarote Island (Central-Eastern Atlantic)

Science.gov (United States)

Tuset, V. M.; García-Díaz, M. M.; González, J. A.; Lorente, M. J.; Lozano, I. J.

2005-08-01

The population biology of painted comber Serranus scriba (Linnaeus, 1758) of the Canary Islands coast was studied to estimate gonad morphology, sexuality, age and growth. Analysis of gonad organization and development revealed that it is a functional simultaneous hermaphrodite. Its anatomy and growth pattern of the reproductive cells is similar to that described in other species of the genus Serranus, although the sequence of vesicles appearing varies during vitellogenesis. Spawning season occurred from January to September with a peak in June. Individuals reached 50% maturity at 17.3 cm TL and 95% at 22.7 cm TL. Length-weight relationship was described by the following parameters: a = 0.01 and b = 3.10, being allometric positive. Age was determined from annuli in whole forming an opaque zone and a translucent zone in each annulus per year. The high percentage of otoliths with translucent zone during the annual cycle indicated that this species presents continuous growth throughout the year. Age range was 2-11 years for fish measuring 15.0-29.4 cm TL. This species is slow-growing and long lived. The growth parameters obtained were L∞ = 34.18 cm TL, k = 0.13 years -1, and to = -2.50 years. Otolith length was the best predictor of fish length, while the otolith weight was the best predictor of age.

Plant Reproduction and the Pollen Tube Journey--How the Females Lure the Males

Science.gov (United States)

Lorbiecke, Rene

2012-01-01

The growth of pollen tubes is one of the most characteristic events in angiosperm reproduction. This article describes an activity for visualizing the journey and guidance of pollen tubes in the reproductive structures of a flowering plant. The activity uses a semi-in vivo system with rapid-cycling "Brassica rapa," also known as Fast Plants.…

Reproductive performance of gilts according to growth rate and backfat thickness at mating.

Science.gov (United States)

Amaral Filha, W S; Bernardi, M L; Wentz, I; Bortolozzo, F P

2010-08-01

The study evaluated the influence of growth rate (GR) and backfat thickness (BF), at first mating of gilts, on the reproductive performance until the first farrowing and on the variation in birth weight of piglets. Gilts were categorized into three groups according to GR from birth until the first mating: GRI (600-700 g/d; n = 345), GRII (701-770 g/d; n = 710) and GRIII (771-870 g/d; n = 366). Analyses were also performed considering three groups formed according to BF (mm) at mating: BFI (10-15 mm; n = 405); BFII (16-17 mm; n = 649)and BFIII (18-23 mm; n = 367). There were no differences in farrowing rate and return to estrus rate among BF or GR groups (P > 0.05). GRII and GRIII females had larger litter size compared to GRI gilts (P GRI and GRII females. Moreover GRIII females had more piglets (P GRI females. More total born and born alive piglets were observed in BFII compared with BFI females (P 0.05). These results show that there is no advantage, in terms of farrowing rate and number of born alive, in performing the first mating of gilts with GR> 770 g/d and BF > 17 mm.

Water fleas require microbiota for survival, growth and reproduction.

Science.gov (United States)

Sison-Mangus, Marilou P; Mushegian, Alexandra A; Ebert, Dieter

2015-01-01

Microbiota have diverse roles in the functioning of their hosts; experiments using model organisms have enabled investigations into these functions. In the model crustacean Daphnia, little knowledge exists about the effect of microbiota on host well being. We assessed the effect of microbiota on Daphnia magna by experimentally depriving animals of their microbiota and comparing their growth, survival and fecundity to that of their bacteria-bearing counterparts. We tested Daphnia coming from both lab-reared parthenogenetic eggs of a single genotype and from genetically diverse field-collected resting eggs. We showed that bacteria-free hosts are smaller, less fecund and have higher mortality than those with microbiota. We also manipulated the association by exposing bacteria-free Daphnia to a single bacterial strain of Aeromonas sp., and to laboratory environmental bacteria. These experiments further demonstrated that the Daphnia-microbiota system is amenable to manipulation under various experimental conditions. The results of this study have implications for studies of D. magna in ecotoxicology, ecology and environmental genomics.

Pollution externalities in a Schumpeterian growth model

OpenAIRE

Koesler, Simon

2010-01-01

This paper extends a standard Schumpeterian growth model to include an environmental dimension. Thereby, it explicitly links the pollution intensity of economic activity to technological progress. In a second step, it investigates the effect of pollution on economic growth under the assumption that pollution intensities are related to technological progress. Several conclusions emerge from the model. In equilibrium, the economy follows a balanced growth path. The effect of pollution on the ec...

Microbiota Influences Morphology and Reproduction of the Brown Alga Ectocarpus sp.

Science.gov (United States)

Tapia, Javier E; González, Bernardo; Goulitquer, Sophie; Potin, Philippe; Correa, Juan A

2016-01-01

Associated microbiota play crucial roles in health and disease of higher organisms. For macroalgae, some associated bacteria exert beneficial effects on nutrition, morphogenesis and growth. However, current knowledge on macroalgae-microbiota interactions is mostly based on studies on green and red seaweeds. In this study, we report that when cultured under axenic conditions, the filamentous brown algal model Ectocarpus sp. loses its branched morphology and grows with a small ball-like appearance. Nine strains of periphytic bacteria isolated from Ectocarpus sp. unialgal cultures were identified by 16S rRNA sequencing, and assessed for their effect on morphology, reproduction and the metabolites secreted by axenic Ectocarpus sp. Six of these isolates restored morphology and reproduction features of axenic Ectocarpus sp. Bacteria-algae co-culture supernatants, but not the supernatant of the corresponding bacterium growing alone, also recovered morphology and reproduction of the alga. Furthermore, colonization of axenic Ectocarpus sp. with a single bacterial isolate impacted significantly the metabolites released by the alga. These results show that the branched typical morphology and the individuals produced by Ectocarpus sp. are strongly dependent on the presence of bacteria, while the bacterial effect on the algal exometabolome profile reflects the impact of bacteria on the whole physiology of this alga.

Growth and Your 13-to 18-Year-Old

Science.gov (United States)

... A Parent's Guide to Surviving the Teen Years Male Reproductive System Your Child's Checkup: 14 Years Your Child's Checkup: ... Height? When Will I Start Developing? Growth Problems Male Reproductive System Everything You Wanted to Know About Puberty Help! ...

Mechanistic model for microbial growth on hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Mallee, F M; Blanch, H W

1977-12-01

Based on available information describing the transport and consumption of insoluble alkanes, a mechanistic model is proposed for microbial growth on hydrocarbons. The model describes the atypical growth kinetics observed, and has implications in the design of large scale equipment for single cell protein (SCP) manufacture from hydrocarbons. The model presents a framework for comparison of the previously published experimental kinetic data.

Reproductive endocrinology of vitamin D.

Science.gov (United States)

Lorenzen, Mette; Boisen, Ida Marie; Mortensen, Li Juel; Lanske, Beate; Juul, Anders; Blomberg Jensen, Martin

2017-09-15

Vitamin D is a versatile hormone with several functions beyond its well-established role in maintenance of skeletal health and calcium homeostasis. The effects of vitamin D are mediated by the vitamin D receptor, which is expressed together with the vitamin D metabolizing enzymes in the reproductive tissues. The reproductive organs are therefore responsive to and able to metabolize vitamin D locally. The exact role remains to be clarified but several studies have suggested a link between vitamin D and production/release of reproductive hormones into circulation, which will be the main focus of this review. Current evidence is primarily based on small human association studies and rodent models. This highlights the need for randomized clinical trials, but also functional animal and human in vitro studies, and larger, prospective cohort studies are warranted. Given the high number of men and women suffering from reproductive problems and abnormal endocrinology research addressing the role of vitamin D in reproductive endocrinology may be of clinical importance. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of oxidative stress in female reproduction

Directory of Open Access Journals (Sweden)

Sharma Rakesh K

2005-07-01

embryopathies, preterm labour and preeclampsia and gestational diabetes. The review also addresses the growing literature on the role of nitric oxide species in female reproduction. The involvement of nitric oxide species in regulation of endometrial and ovarian function, etiopathogenesis of endometriosis, and maintenance of uterine quiescence, initiation of labour and ripening of cervix at parturition is discussed. Complex interplay between cytokines and oxidative stress in the etiology of female reproductive disorders is discussed. Oxidant status of the cell modulates angiogenesis, which is critical for follicular growth, corpus luteum formation endometrial differentiation and embryonic growth is also highlighted in the review. Strategies to overcome oxidative stress and enhance fertility, both natural and assisted are delineated. Early interventions being investigated for prevention of preeclampsia are enumerated. Trials investigating combination intervention strategy of vitamin E and vitamin C supplementation in preventing preeclampsia are highlighted. Antioxidants are powerful and there are few trials investigating antioxidant supplementation in female reproduction. However, before clinicians recommend antioxidants, randomized controlled trials with sufficient power are necessary to prove the efficacy of antioxidant supplementation in disorders of female reproduction. Serial measurement of oxidative stress biomarkers in longitudinal studies may help delineate the etiology of some of the diosorders in female reproduction such as preeclampsia.

Value function in economic growth model

Science.gov (United States)

Bagno, Alexander; Tarasyev, Alexandr A.; Tarasyev, Alexander M.

2017-11-01

Properties of the value function are examined in an infinite horizon optimal control problem with an unlimited integrand index appearing in the quality functional with a discount factor. Optimal control problems of such type describe solutions in models of economic growth. Necessary and sufficient conditions are derived to ensure that the value function satisfies the infinitesimal stability properties. It is proved that value function coincides with the minimax solution of the Hamilton-Jacobi equation. Description of the growth asymptotic behavior for the value function is provided for the logarithmic, power and exponential quality functionals and an example is given to illustrate construction of the value function in economic growth models.

The effect of dietary restriction on reproduction: a meta-analytic perspective.

Science.gov (United States)

Moatt, Joshua P; Nakagawa, Shinichi; Lagisz, Malgorzata; Walling, Craig A

2016-10-07

Dietary restriction (DR), a reduction in the amount of food or particular nutrients eaten, is the most consistent environmental manipulation to extend lifespan and protect against age related diseases. Current evolutionary theory explains this effect as a shift in the resolution of the trade-off between lifespan and reproduction. However, recent studies have questioned the role of reproduction in mediating the effect of DR on longevity and no study has quantitatively investigated the effect of DR on reproduction across species. Here we report a comprehensive comparative meta-analysis of the effect of DR on reproduction. In general, DR reduced reproduction across taxa, but several factors moderated this effect. The effect of DR on reproduction was greater in well-studied model species (yeast, nematode worms, fruit flies and rodents) than non-model species. This mirrors recent results for longevity and, for reproduction, seems to result from a faster rate of decline with decreasing resources in model species. Our results also suggested that not all reproductive traits are affected equally by DR. High and moderate cost reproductive traits suffered a significant reduction with DR, but low cost traits, such as ejaculate production, did not. Although the effect of DR on reproduction was stronger in females than males, this sex difference reduced to near zero when accounting for other co-factors such as the costliness of the reproductive trait. Thus, sex differences in the effect of DR on longevity may be due to a failure to expose males to as complete a range of the costs of reproduction as females. We suggest that to better understand the generality of the effect of DR, future studies should attempt to address the cause of the apparent model species bias and ensure that individuals are exposed to as many of the costs of reproduction as possible. Furthermore, our meta-analytic approach reveals a general shortage of DR studies that record reproduction, particularly in

A Model of Controlled Growth

Science.gov (United States)

Bressan, Alberto; Lewicka, Marta

2018-03-01

We consider a free boundary problem for a system of PDEs, modeling the growth of a biological tissue. A morphogen, controlling volume growth, is produced by specific cells and then diffused and absorbed throughout the domain. The geometric shape of the growing tissue is determined by the instantaneous minimization of an elastic deformation energy, subject to a constraint on the volumetric growth. For an initial domain with C}^{2,α boundary, our main result establishes the local existence and uniqueness of a classical solution, up to a rigid motion.

A critical number of workers in a honeybee colony triggers investment in reproduction.

Science.gov (United States)

Smith, Michael L; Ostwald, Madeleine M; Loftus, J Carter; Seeley, Thomas D

2014-10-01

Social insect colonies, like individual organisms, must decide as they develop how to allocate optimally their resources among survival, growth, and reproduction. Only when colonies reach a certain state do they switch from investing purely in survival and growth to investing also in reproduction. But how do worker bees within a colony detect that their colony has reached the state where it is adaptive to begin investing in reproduction? Previous work has shown that larger honeybee colonies invest more in reproduction (i.e., the production of drones and queens), however, the term 'larger' encompasses multiple colony parameters including number of adult workers, size of the nest, amount of brood, and size of the honey stores. These colony parameters were independently increased in this study to test which one(s) would increase a colony's investment in reproduction via males. This was assayed by measuring the construction of drone comb, the special type of comb in which drones are reared. Only an increase in the number of workers stimulated construction of drone comb. Colonies with over 4,000 workers began building drone comb, independent of the other colony parameters. These results show that attaining a critical number of workers is the key parameter for honeybee colonies to start to shift resources towards reproduction. These findings are relevant to other social systems in which a group's members must adjust their behavior as a function of the group's size.

A critical number of workers in a honeybee colony triggers investment in reproduction

Science.gov (United States)

Smith, Michael L.; Ostwald, Madeleine M.; Loftus, J. Carter; Seeley, Thomas D.

2014-10-01

Social insect colonies, like individual organisms, must decide as they develop how to allocate optimally their resources among survival, growth, and reproduction. Only when colonies reach a certain state do they switch from investing purely in survival and growth to investing also in reproduction. But how do worker bees within a colony detect that their colony has reached the state where it is adaptive to begin investing in reproduction? Previous work has shown that larger honeybee colonies invest more in reproduction (i.e., the production of drones and queens), however, the term `larger' encompasses multiple colony parameters including number of adult workers, size of the nest, amount of brood, and size of the honey stores. These colony parameters were independently increased in this study to test which one(s) would increase a colony's investment in reproduction via males. This was assayed by measuring the construction of drone comb, the special type of comb in which drones are reared. Only an increase in the number of workers stimulated construction of drone comb. Colonies with over 4,000 workers began building drone comb, independent of the other colony parameters. These results show that attaining a critical number of workers is the key parameter for honeybee colonies to start to shift resources towards reproduction. These findings are relevant to other social systems in which a group's members must adjust their behavior as a function of the group's size.

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.

Calibration aspects of binaural sound reproduction over insert earphones

DEFF Research Database (Denmark)

Hoffmann, Pablo F.; Markovic, Milos; Olesen, Søren Krarup

2012-01-01

Earphones are nowadays widely adopted for the reproduction of audio material in mobile multimedia and communication platforms, e.g. smartphones. Reproduction of high-quality spatial sound on such platforms can dramatically improve their applicability, and since two channels are always available...... in earphone-based reproduction, binaural reproduction can be applied directly. This paper is concerned with the theoretical and practical aspects relevant to the correct reproduction of binaural signals over insert earphones. To this purpose, a theoretical model originally developed to explain the acoustic...

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.

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...

Reproductive rights approach to reproductive health in developing countries

OpenAIRE

Pillai, Vijayan Kumara; Gupta, Rashmi

2011-01-01

Background: Research on reproductive health in developing countries focuses mostly on the role of economic development on various components of reproductive health. Cross-sectional and empirical research studies in particular on the effects of non-economic factors such as reproductive rights remain few and far between. Objective: This study investigates the influence of two components of an empowerment strategy, gender equality, and reproductive rights on women’s reproductive health in develo...

On Latent Growth Models for Composites and Their Constituents.

Science.gov (United States)

Hancock, Gregory R; Mao, Xiulin; Kher, Hemant

2013-09-01

Over the last decade and a half, latent growth modeling has become an extremely popular and versatile technique for evaluating longitudinal change and its determinants. Most common among the models applied are those for a single measured variable over time. This model has been extended in a variety of ways, most relevant for the current work being the multidomain and the second-order latent growth models. Whereas the former allows for growth function characteristics to be modeled for multiple outcomes simultaneously, with the degree of growth characteristics' relations assessed within the model (e.g., cross-domain slope factor correlations), the latter models growth in latent outcomes, each of which has effect indicators repeated over time. But what if one has an outcome that is believed to be formative relative to its indicator variables rather than latent? In this case, where the outcome is a composite of multiple constituents, modeling change over time is less straightforward. This article provides analytical and applied details for simultaneously modeling growth in composites and their constituent elements, including a real data example using a general computer self-efficacy questionnaire.

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.

[The function of ERα in male reproductive system].

Science.gov (United States)

Dong, Yu-Hang; Wei, Jin-Hua; Li, Zhen

2014-12-01

Estrogen receptors (ERs), including two sub-types ERα and ERβ, belong to the steroid hormone superfamily of nuclear receptors. ERα distributes in the male reproductive system and plays a crucial role in the regulation of male reproduction through estrogen-dependent and -independent ways. In this article, we mainly reviewed the molecular structure, mode of action and location of ERα in the male reproductive system, and explored the mechanism of ERα in regulating the male reproductive system by analyzing different animal models of disrupted ERα.

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.

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.

[Fitness of sexual reproduction of Toona ciliata var. pubescens natural populations and their sexual reproduction and regeneration].

Science.gov (United States)

Huang, Hong Lan; Zhang, Lu; Jia, Li Ming; Liang, Yue-Long; Cai, Jun Huo

2018-04-01

To examine the reproduction fitness coefficients and individual-level fitness of Toona ciliata var. pubescens, their sexual reproduction and natural regeneration were investigated during 2006-2016, with four natural populations in Jiulianshan National Reserve as test objects. The results showed that there were only 2-10 trees for the natural populations of T. ciliata var. pubescens with a small initial number of fruiting plants (3-9 trees), which were from the initial fruiting plants or their first/second generation. The sexual reproduction of these isolated populations were significantly different, and their seed production capacities tended to decline over time. With the maturing of communities, soil seed banks and seed germinations were extremely poor, and the number of trees that could be growing to mature stage was nearly zero. The optimum maturity age of T. ciliata var. pubescens was about 40 a, and the fitness coefficients (2.0-2.8) rapidly increased in early development stage, but then was sharply reduced (0.3-0.5), and then gradually dropped to almost 0. There were significant differences in the fitness at individual level (0-14 tree·cm -2 ) among different populations, but their values were low (close to zero). Based on the existing reproduction rate, the actual values of sexual reproduction and regeneration fitness were much lower than the predicted ones. Due to the low level of genetic fitness, the sexual reproductive ability of different populations all showed decreasing trends. The natural sexual regeneration ability tended to decline, while the fitness of T. ciliata var. pubescens further decreased. All those factors suggested higher investment risks. Therefore, the systems of sexual reproduction became unbalanced and deteriorating. We proposed that more studies, including breeding mating, pollination, seed setting, and genetic diversity evaluation, are needed. Moreover, we should provide suitable forest environment through cleaning up litter in the

Zika Virus in the Male Reproductive Tract

Directory of Open Access Journals (Sweden)

Liesel Stassen

2018-04-01

Full Text Available Arthropod-borne viruses (arboviruses are resurging across the globe. Zika virus (ZIKV has caused significant concern in recent years because it can lead to congenital malformations in babies and Guillain-Barré syndrome in adults. Unlike other arboviruses, ZIKV can be sexually transmitted and may persist in the male reproductive tract. There is limited information regarding the impact of ZIKV on male reproductive health and fertility. Understanding the mechanisms that underlie persistent ZIKV infections in men is critical to developing effective vaccines and therapies. Mouse and macaque models have begun to unravel the pathogenesis of ZIKV infection in the male reproductive tract, with the testes and prostate gland implicated as potential reservoirs for persistent ZIKV infection. Here, we summarize current knowledge regarding the pathogenesis of ZIKV in the male reproductive tract, the development of animal models to study ZIKV infection at this site, and prospects for vaccines and therapeutics against persistent ZIKV infection.

Conflict over reproduction in an ant-plant symbiosis: why Allomerus octoarticulatus ants sterilize Cordia nodosa trees.

Science.gov (United States)

Frederickson, Megan E

2009-05-01

The evolutionary stability of mutualism is thought to depend on how well the fitness interests of partners are aligned. Because most ant-myrmecophyte mutualisms are persistent and horizontally transmitted, partners share an interest in growth but not in reproduction. Resources invested in reproduction are unavailable for growth, giving rise to a conflict of interest between partners. I investigated whether this explains why Allomerus octoarticulatus ants sterilize Cordia nodosa trees. Allomerus octoarticulatus nests in the hollow stem domatia of C. nodosa. Workers protect C. nodosa leaves against herbivores but destroy inflorescences. Using C. nodosa trees with Azteca ants, which do not sterilize their hosts, I cut inflorescences off trees to simulate sterilization by A. octoarticulatus. Sterilized C. nodosa grew faster than control trees, providing evidence for a trade-off between growth and reproduction. Allomerus octoarticulatus manipulates this trade-off to its advantage; sterilized trees produce more domatia and can house larger, more fecund colonies.

Impact of Microplastic Beads and Fibers on Waterflea (Ceriodaphnia dubia) Survival, Growth, and Reproduction: Implications of Single and Mixture Exposures.

Science.gov (United States)

Ziajahromi, Shima; Kumar, Anupama; Neale, Peta A; Leusch, Frederic D L

2017-11-21

There is limited knowledge regarding the adverse effects of wastewater-derived microplastics, particularly fibers, on aquatic biota. In this study, we examined the acute (48 h) and chronic (8 d) effects of microplastic polyester fibers and polyethylene (PE) beads on freshwater zooplankton Ceriodaphnia dubia. We also assessed the acute response of C. dubia to a binary mixture of microplastic beads and fibers for the first time. Acute exposure to fibers and PE beads both showed a dose-dependent effect on survival. An equitoxic binary mixture of beads and fibers resulted in a toxic unit of 1.85 indicating less than additive effects. Chronic exposure to lower concentrations did not significantly affect survival of C. dubia, but a dose-dependent effect on growth and reproduction was observed. Fibers showed greater adverse effects than PE beads. While ingestion of fibers was not observed, scanning electron microscopy showed carapace and antenna deformities after exposure to fibers, with no deformities observed after exposure to PE beads. While much of the current research has focused on microplastic beads, our study shows that microplastic fibers pose a greater risk to C. dubia, with reduced reproductive output observed at concentrations within an order of magnitude of reported environmental levels.

A multiscale model on hospital infections coupling macro and micro dynamics

Science.gov (United States)

Wang, Xia; Tang, Sanyi

2017-09-01

A multiscale model of hospital infections coupling the micro model of the growth of bacteria and the macro model describing the transmission of the bacteria among patients and health care workers (HCWs) was established to investigate the effects of antibiotic treatment on the transmission of the bacteria among patients and HCWs. The model was formulated by viewing the transmission rate from infected patients to HCWs and the shedding rate of bacteria from infected patients to the environment as saturated functions of the within-host bacterial load. The equilibria and the basic reproduction number of the coupled system were studied, and the global dynamics of the disease free equilibrium and the endemic equilibrium were analyzed in detail by constructing two Lyapunov functions. Furthermore, effects of drug treatment in the within-host model on the basic reproduction number and the dynamics of the coupled model were studied by coupling a pharmacokinetics model with the within-host model. Sensitive analysis indicated that the growth rate of the bacteria, the maximum drug effect and the dosing interval are the three most sensitive parameters contributing to the basic reproduction number. Thus, adopting ;wonder; drugs to decrease the growth rate of the bacteria or to increase the drug's effect is the most effective measure but changing the dosage regime is also effective. A quantitative criterion of how to choose the best dosage regimen can also be obtained from numerical results.

Photosynthetic Entrainment of the Circadian Clock Facilitates Plant Growth under Environmental Fluctuations: Perspectives from an Integrated Model of Phase Oscillator and Phloem Transportation

Directory of Open Access Journals (Sweden)

Takayuki Ohara

2017-10-01

Full Text Available Plants need to avoid carbon starvation and resultant growth inhibition under fluctuating light environments to ensure optimal growth and reproduction. As diel patterns of carbon metabolism are influenced by the circadian clock, appropriate regulation of the clock is essential for plants to properly manage their carbon resources. For proper adjustment of the circadian phase, higher plants utilize environmental signals such as light or temperature and metabolic signals such as photosynthetic products; the importance of the latter as phase regulators has been recently elucidated. A mutant of Arabidopsis thaliana that is deficient in phase response to sugar has been shown, under fluctuating light conditions, to be unable to adjust starch turnover and to realize carbon homeostasis. Whereas, the effects of light entrainment on growth and survival of higher plants are well studied, the impact of phase regulation by sugar remains unknown. Here we show that endogenous sugar entrainment facilitates plant growth. We integrated two mathematical models, one describing the dynamics of carbon metabolism in A. thaliana source leaves and the other growth of sink tissues dependent on sucrose translocation from the source. The integrated model predicted that sugar-sensitive plants grow faster than sugar-insensitive plants under constant as well as changing photoperiod conditions. We found that sugar entrainment enables efficient carbon investment for growth by stabilizing sucrose supply to sink tissues. Our results highlight the importance of clock entrainment by both exogenous and endogenous signals for optimizing growth and increasing fitness.

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

Factors affecting reproduction in Merino ewes of the Tygerhoek flock

African Journals Online (AJOL)

ouderdomsgroepe ... paarmassa teen 'n skerper helling toe te neem as by enkelinge. S.-Afr. Tydskr. Veek. 1986, 16: 36 - 42. Keywords: ..... growth and reproductive performance in young sheep given differential nutrition from 9 to 18 months of age.

Interspecific differences in the effects of sulfur dioxide on angiosperm sexual reproduction

International Nuclear Information System (INIS)

DuBay, D.T.

1981-01-01

The major objective of this study was to test the potential direct effects of SO 2 on sexual reproduction in several plant species with different reproductive structures and processes. In marked contrast to the sensitivity to SO 2 reported by other investigators for pollen germination and pollen tube growth in vitro, and recorded for Lepidium virginicum in this study, 4 of 5 species tested were tolerant with respect to fruit and seed set after exposure to 0.6 ppm SO 2 for 8 hours during flowering. Seed set in the one sensitive species, Geranium carolinianum, was reduced 40% from the control after exposure to SO 2 , but only when relative humidity (RH) was at or above 90%. The effect of SO 2 on Lepidium pollen germination in vitro was greater than the effect of SO 2 on sexual reproduction in vivo. Sulfur dioxide reduced pollen germination in vitro 94% from the control. The same concentration of SO 2 , at 90% Rh, reduced pollen germination in vivo 50% from the control, but had no effect on seed set. Predictions of effects of SO 2 on reproduction in vivo based on effects of SO 2 on pollen germination and pollen tube growth in vitro are not valid

Detecting Growth Shape Misspecifications in Latent Growth Models: An Evaluation of Fit Indexes

Science.gov (United States)

Leite, Walter L.; Stapleton, Laura M.

2011-01-01

In this study, the authors compared the likelihood ratio test and fit indexes for detection of misspecifications of growth shape in latent growth models through a simulation study and a graphical analysis. They found that the likelihood ratio test, MFI, and root mean square error of approximation performed best for detecting model misspecification…

Growth, Survival and Reproduction of the Giant Clam Tridacna maxima (Röding 1798, Bivalvia) in Two Contrasting Lagoons in French Polynesia

Science.gov (United States)

Van Wynsberge, Simon; Andréfouët, Serge; Gaertner-Mazouni, Nabila; Wabnitz, Colette C. C.; Menoud, Mathilde; Le Moullac, Gilles; Levy, Peva; Gilbert, Antoine; Remoissenet, Georges

2017-01-01

Shell growth, reproduction, and natural mortality of the giant clam Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai (Austral Archipelago) and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago) in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity indices in June and July 2014, were timed with high oceanic water inflow and a decrease in lagoon water temperature. Secondly, temperature explained differences in shell growth rates between seasons and lagoons, generating different growth curves for the two sites. Thirdly, local mortality rates were also found to likely be related to water renewal patterns. In conclusion, our study suggests that reef aperture and lagoon water renewal rates play an integral role in giant clam life history, with significant differences in rates of shell growth, mortality and fertility found between open versus semi-closed atoll lagoons in coral reef ecosystems. PMID:28118406

Growth, Survival and Reproduction of the Giant Clam Tridacna maxima (Röding 1798, Bivalvia in Two Contrasting Lagoons in French Polynesia.

Directory of Open Access Journals (Sweden)

Simon Van Wynsberge

Full Text Available Shell growth, reproduction, and natural mortality of the giant clam Tridacna maxima were characterized over a two-year-period in the lagoon of the high island of Tubuai (Austral Archipelago and in the semi-closed lagoon of Tatakoto (Tuamotu Archipelago in French Polynesia. We also recorded temperature, water level, tidal slope, tidal range, and mean wave height in both lagoons. Lower lagoon aperture and exposure to oceanic swells at Tatakoto than at Tubuai was responsible for lower lagoon water renewal, as well as higher variability in temperature and water level at Tatakoto across the studied period. These different environmental conditions had an impact on giant clams. Firstly, spawning events in the lagoon of Tatakoto, detected by gonad maturity indices in June and July 2014, were timed with high oceanic water inflow and a decrease in lagoon water temperature. Secondly, temperature explained differences in shell growth rates between seasons and lagoons, generating different growth curves for the two sites. Thirdly, local mortality rates were also found to likely be related to water renewal patterns. In conclusion, our study suggests that reef aperture and lagoon water renewal rates play an integral role in giant clam life history, with significant differences in rates of shell growth, mortality and fertility found between open versus semi-closed atoll lagoons in coral reef ecosystems.

Modeling urban fire growth

International Nuclear Information System (INIS)

Waterman, T.E.; Takata, A.N.

1983-01-01

The IITRI Urban Fire Spread Model as well as others of similar vintage were constrained by computer size and running costs such that many approximations/generalizations were introduced to reduce program complexity and data storage requirements. Simplifications were introduced both in input data and in fire growth and spread calculations. Modern computational capabilities offer the means to introduce greater detail and to examine its practical significance on urban fire predictions. Selected portions of the model are described as presently configured, and potential modifications are discussed. A single tract model is hypothesized which permits the importance of various model details to be assessed, and, other model applications are identified

Selection for growth and maternal ability impacts simulation on the reproductive efficiency in a nellore herd Simulação dos impactos da seleção para crescimento e habilidade materna sobre a eficiência reprodutiva de um rebanho nelore

Directory of Open Access Journals (Sweden)

Moarcir Gabriel Saueressig

2010-09-01

Full Text Available The aim in this work was, using a simulation model, to verify the result of twenty years of selection for growth and maternal ability on the reproductive traits in a selection Nellore herd raised in the savannah biome. Data were reported to the DECI (Decision Evaluator for the Industry Cattle simulation model, reflecting the real situation of registered purebred Nellore herd of the Embrapa Cerrados (Brazil Nellore Genetics. The simulation model was effective in predicting the impacts of the selection for growth and maternal ability on the reproductive efficiency. In agreement with the program, at 20 years of selection, the medium puberty age of the herd would be 14,4 months, the age to the first partum 24,7 months, the service period 78 days, and the pregnancy rate 77%. Under the simulated conditions, it was possible to conclude that the selection for growth and maternal ability for 20 years in a Nellore herd did not affect negatively the reproductive performance of the herd.Objetivou-se, neste trabalho, verificar por meio de um programa de simulação o resultado de vinte anos de seleção para crescimento e habilidade materna sobre as características reprodutivas em um rebanho seleção Nelore puro de origem, marca BRGN (Brasil Genética Nelore criado no bioma Cerrado. O programa de simulação utilizado foi o DECI (Decision Evaluator for the Industry Cattle. Os dados informados ao programa buscaram refletir o mais fielmente possível o sistema de produção do rebanho Nelore BRGN da Embrapa Cerrados. O modelo de simulação foi eficaz em predizer os impactos da seleção para crescimento e habilidade materna sobre a eficiência reprodutiva. Ao final de 20 anos de seleção, a idade à puberdade média do rebanho seria 14,4 meses, a idade ao primeiro parto 24,7 meses, o período de serviço 78 dias e a taxa de prenhez 77%. Sob as condições simuladas, foi possível concluir que a seleção para crescimento e habilidade materna por 20 anos em

Initial Effects of Reproduction Cutting Treatments on Residual Hard Mast Production in the Ouachita Mountains

Science.gov (United States)

Roger W. Perry; Ronald E. Thill

2003-01-01

We compared indices of total hard mast production (oak and hickory combined) in 20, second-growth, pine-hardwood stands under five treatments to determine the effects of different reproduction treatments on mast production in the Ouachita Mountains. We evaluated mast production in mature unharvested controls and stands under four reproduction cutting methods (single-...

Male Reproductive Toxicology: Environmental Exposures vs Reproductive Competence

Science.gov (United States)

Like the lecture this chapter begins with an overview of male reproductive biology and transitions into male reproductive toxicology. It ends with a brief discussion of the strengths and weaknesses in male reproductive toxicology and epidemiology today. This chapter is highly il...

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.

Neo-logistic model for the growth of bacteria

OpenAIRE

Tashiro, Tohru; Yoshimura, Fujiko

2017-01-01

We propose a neo-logistic model that can describe bacterial growth data precisely. This model is not derived by modifying the logistic model formally, but by incorporating the synthesis of inducible enzymes into the logistic model indirectly. Therefore, the meaning of the parameters of the neo-logistic model becomes physically clear. The neo-logistic model can approximate bacterial growth better than models previously presented, and predict the order of the saturated number of bacteria in the...

Life-history tradeoffs and reproductive cycles in Spotted Owls

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Stoelting, Ricka E.; Gutierrez, R.J.; Kendall, William L.; Peery, M. Zachariah

2015-01-01

The study of tradeoffs among life-history traits has long been key to understanding the evolution of life-history strategies. However, more recently, evolutionary ecologists have realized that reproductive costs have the potential to influence population dynamics. Here, we tested for costs of reproduction in the California Spotted Owl (Strix occidentalis occidentalis), and assessed whether costs of reproduction in year t − 1 on reproduction in year t could be responsible for regionally synchronized biennial cycles in reproductive output. Logistic regression analysis and multistate mark–recapture models with state uncertainty revealed that breeding reduced the likelihood of reproducing in the subsequent year by 16% to 38%, but had no influence on subsequent survival. We also found that costs of reproduction in year t − 1 were correlated with climatic conditions in year t, with evidence of higher costs during the dry phase of the El Niño–Southern Oscillation. Using a simulation-based population model, we showed that strong reproductive costs had the potential to create biennial cycles in population-level reproductive output; however, estimated costs of reproduction appeared to be too small to explain patterns observed in Spotted Owls. In the absence of strong reproductive costs, we hypothesize that observed natural cycles in the reproductive output of Spotted Owls are related to as-yet-unmeasured, regionally concordant fluctuations in environmental conditions or prey resources. Despite theoretical evidence for demographic effects, our analyses illustrate that linking tradeoffs to actual changes in population processes will be challenging because of the potential confounding effects of individual and environmental variation.

Female reproductive disorders

DEFF Research Database (Denmark)

Crain, D Andrew; Janssen, Sarah J; Edwards, Thea M

2008-01-01

To evaluate the possible role of endocrine-disrupting compounds (EDCs) on female reproductive disorders emphasizing developmental plasticity and the complexity of endocrine-dependent ontogeny of reproductive organs. Declining conception rates and the high incidence of female reproductive disrupti......To evaluate the possible role of endocrine-disrupting compounds (EDCs) on female reproductive disorders emphasizing developmental plasticity and the complexity of endocrine-dependent ontogeny of reproductive organs. Declining conception rates and the high incidence of female reproductive...... disruptions warrant evaluation of the impact of EDCs on female reproductive health....

Reproductive biology in the medicinal plant, Plumbago zeylanica L ...

African Journals Online (AJOL)

Plumbago zeylanica L. is an important medicinal plant traditionally used for the treatment of various diseases. Phenology from seed germination via vegetative growth to reproductive development was studied under glasshouse and nursery conditions. Seeds rapidly germinated on a mixture of nursery soil and cattle dung in ...

Density-dependent reproductive and vegetative allocation in the aquatic plant Pistia stratiotes (Araceae

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Flávia Freitas Coelho

2005-09-01

Full Text Available Pistia stratiotes is an aquatic macrophyte that grows in temporary-ponds in the southern Pantanal, Brazil. It reproduces both sexually and asexually and is usually observed forming dense mats on the water surface, a condition favored by the plant’s vegetative reproduction coupled with an ability for rapid growth. In this study we examined the effect of densely crowded conditions on the production of reproductive and vegetative structures. In addition, we verified whether there is a trade-off between clonal growth and investment in sexual reproductive structures, and whether there is an allocation pattern with plant size. Individual plant biomass and the number of the rosettes producing sexual reproductive structures and vegetative growth structures both increased with density. Increase in plant size resulted in increased proportional allocation to sexual reproductive structures and vegetative growth structures. Allocation of biomass to reproduction did not occur at the expense of clonal growth. Thus, the density response appears as a increase of rosettes producing sexual reproductive structures and vegetative growth structures. Therefore, long leaves and stolons may be adaptive under densely crowded conditions where competition for light is intense. An important aspect in the study of trade-offs is the size-dependency of the allocation patterns .Usually, larger plants produce more biomass. Therefore, larger plants can allocate more biomass to both vegetative and sexual reproduction than smaller plants and thus show a positive correlation between both traits rather than the expected negative one. Rev. Biol. Trop. 53(3-4: 369-376. Epub 2005 Oct 3.Pistias strariotes es una macrófita acuática que crece en charcas estacionales en el Pantanal sureño de Brasil. Se reproduce tanto sexual como asexualmente y se obsrva generalmente que forma densas parches sobre la superficie del agua, una condicion que favorecida por la reproduccion vegetativa de la

Non-linear Growth Models in Mplus and SAS

Science.gov (United States)

Grimm, Kevin J.; Ram, Nilam

2013-01-01

Non-linear growth curves or growth curves that follow a specified non-linear function in time enable researchers to model complex developmental patterns with parameters that are easily interpretable. In this paper we describe how a variety of sigmoid curves can be fit using the Mplus structural modeling program and the non-linear mixed-effects modeling procedure NLMIXED in SAS. Using longitudinal achievement data collected as part of a study examining the effects of preschool instruction on academic gain we illustrate the procedures for fitting growth models of logistic, Gompertz, and Richards functions. Brief notes regarding the practical benefits, limitations, and choices faced in the fitting and estimation of such models are included. PMID:23882134

Modelling diameter growth, mortality and recruitment of trees in ...

African Journals Online (AJOL)

Modelling diameter growth, mortality and recruitment of trees in miombo woodlands of Tanzania. ... Individual tree diameter growth and mortality models, and area-based recruitment models were developed. ... AJOL African Journals Online.