Estimation of the Individual Growth Parameters of the Brown Crab Callinectes Bellicosus (Brachyura, Portunidae) Using a Multi-Model Approach

Crustaceana ◽  
2012 ◽  
Vol 85 (1) ◽  
pp. 55-69 ◽  
2010 ◽  
Vol 69 (1) ◽  
pp. 15-29 ◽  
Author(s):  
Sonja Perren ◽  
Roger Keller ◽  
Marco Passardi ◽  
Urte Scholz

A newly developed instrument (retrospective well-being curves: WBC) was applied in two studies. In Study 1, a sample of 145 adults (M = 26.6 years) completed the WBC twice for different normative transitions. In Study 2, 151 university freshmen (M = 21.5 years) reported on their subjective well-being at 9 consecutive measurement points during their transition to university and completed the WBC at T10. In both studies, personality factors were assessed. Retest reliability of the individual growth parameters (intercept, linear, and quadratic change) was moderate to high (Study 1), whereas convergent validity of the growth parameters was moderate (Study 2). The results demonstrated distinct well-being trajectories for different transitions. Situational factors (e.g., timing) and personality factors (neuroticism and extraversion) were significantly associated with well-being. The results indicate that, although the use of the WBC may be limited by its retrospective design, the instrument provides a time-efficient way of measuring hedonic adaptation processes.


1995 ◽  
Vol 52 (7) ◽  
pp. 1368-1375 ◽  
Author(s):  
Yoy-Gan Wang ◽  
Mervyn R. Thomas

Estimation of von Bertalanffy growth parameters has received considerable attention in fisheries research. Since Sainsbury (1980, Can. J. Fish. Aquat. Sci. 37: 241–247) much of this research effort has centered on accounting for individual variability in the growth parameters. In this paper we demonstrate that, in analysis of tagging data, Sainsbury's method and its derivatives do not, in general, satisfactorily account for individual variability in growth, leading to inconsistent parameter estimates (the bias does not tend to zero as sample size increases to infinity). The bias arises because these methods do not use appropriate conditional expectations as a basis for estimation. This bias is found to be similar to that of the Fabens method. Such methods would be appropriate only under the assumption that the individual growth parameters that generate the growth increment were independent of the growth parameters that generated the initial length. However, such an assumption would be unrealistic. The results are derived analytically, and illustrated with a simulation study. Until techniques that take full account of the appropriate conditioning have been developed, the effect of individual variability on growth has yet to be fully understood.


2021 ◽  
Vol 11 (2) ◽  
pp. 75
Author(s):  
Jan Amos Jelinek

The Earth’s shape concept develops as consecutive cognitive problems (e.g., the location of people and trees on the spherical Earth) are gradually resolved. Establishing the order of problem solving may be important for the organisation of teaching situations. This study attempted to determine the sequence of problems to be resolved based on tasks included in the EARTH2 test. The study covered a group of 444 children between 5 and 10 years of age. It captured the order in which children solve cognitive problems on the way to constructing a science-like concept. The test results were compared with previous studies. The importance of cultural influences connected to significant differences (24%) in test results was emphasised. Attention was drawn to the problem of the consistency of the mental model approach highlighted in the literature. The analysis of the individual sets of answers provided a high level of consistency of indications referring to the same model (36%), emphasising the importance of the concept of mental models.


PEDIATRICS ◽  
1959 ◽  
Vol 24 (5) ◽  
pp. 904-921
Author(s):  
Robert B. Reed ◽  
Harold C. Stuart

In this report is displayed the range of variation observed in the growth curves of height and weight in a series of 134 children observed from birth to 18 years. For purposes of simplification the individuals have been classified on the basis of their rates of growth during three successive 6-year intervals. Even in terms of this crude classification several basic facts about individual growth patterns of height and weight are apparent. The wide range of differences between individuals applies not only to facts about size at specific ages but also to the pattern of change followed from age period to age period. The rate of growth during early childhood, i.e. before 6 years of age, is associated with, but not specifically predictive of, size at maturity and timing of the adolescent growth spurt. Individuals with rapid growth before 6 years of age tend to have large mature size and early adolescent growth spurt. It will be the objective of future reports from this research project to determine the manner in which the individual differences in growth demonstrated and classified here are related to aspects of physical development, to environmental influences such as dietary intake and to the level of health of the child.


2008 ◽  
Vol 68 (3) ◽  
pp. 617-621 ◽  
Author(s):  
SM. Martin

The present work analyses the individual growth of Heleobia piscium in natural conditions in coastal drainage channels of the Multiple Use Natural Reserve Isla Martín García, Buenos Aires, Argentina. Isla Martín García is located in the Upper Río de la Plata, to the south of the mouth of the Uruguay river (34° 11' 25" S and 58° 15' 38" W). Monthly collections were made from July 2005 to July 2006 in the eastern part of the island (Arena Beach). The population of H. piscium showed a complex and dynamic structure of sizes during a long period of the annual cycle. Two cohorts could be detected. The Bertalanffy growth equation was: Lt = 6 (1-e -1.85 (t+0.38)) and Lt = 3.9 (1-e -0.19 (t+4.84)) for cohorts 1 and 2, respectively. The pattern of population growth displayed a staggered model, where the greatest growth is observed during the summer. The reproductive period occurred during six months, from the beginning of summer to middle of fall. Based on only one reproductive effort, this pattern is not similar to that of other cogeneric species already studied.


2021 ◽  
pp. 56-62
Author(s):  
Theophilus Apenuvor ◽  
John Blay ◽  
Joseph Aggreyfynn ◽  
Simon Drafor

Over-population and stunted growth had been major challenges in the culture of tilapia. The use of synthetic androgen 17- α Methyl Testosterone (MT) was a breakthrough. However, its optimum level towards effective masculinization and growth is a concern. The aim of this research was to ascertain the optimum level of MT towards effective all-male population production and growth of Black-Chinned tilapia. In the present study, the effect of different dose rates of synthetic androgen 17-α Methyl Testosterone (MT) i.e., 0, 30, 60, and 120 mg of the hormone per kg of feed on sex, growth, and condition of Black-Chinned tilapia was evaluated. MT was administered orally by using powdered dry starter feed (Crude Protein 40 %) and Ethanol. The fry was fed for 30 days in the experimental tanks. At the end of the experiment, the sex ratios were determined by examining the operculum coloration as a means of sex identification. Growth performance was monitored by measuring and recording the morphometric characteristics. Bodyweight and total length of the fish on the start of feeding, end of feeding (one month sex reversal period), and two months after feeding were measured. The results of the present study showed that all MT receiving treatment showed a significantly higher male proportion than the control (0 mg MT/kg feed individuals). In all MT treatments groups, the control expects the 30 mg MT/kg in feed individuals’ deviate significantly from the normal 1:1 sex ratio (Chi-square analysis). The dose rate of 120 mg MT /kg feed resulted in the maximum male population (92.7%). Hence, for an effective high percentage of all-male population production in Black-Chinned tilapia, 120 mg MT /kg in feed is recommended. In terms of growth and condition factor, all the individual treatments, as well as the control, showed no significant difference. All the treated individuals showed similar condition factors during the pre and post-treatment, however, the individuals treated with 30 mg MT /kg feed exhibited better condition during the pre-treatment than the post-treatment period. Temperature, pH and dissolved oxygen recorded in this study were within the desirable limit for tilapia.


Author(s):  
Ken H. Andersen

This chapter develops descriptions of how individuals grow and reproduce. More specifically, the chapter seeks to determine the growth and reproduction rates from the consumption rate, by developing an energy budget of the individual as a function of size. To that end, the chapter addresses the question of how an individual makes use of the energy acquired from consumption. It sets up the energy budgets of individuals by formulating the growth model using so-called life-history invariants, which are parameters that do not vary systematically between species. While the formulation of the growth model in terms of life-history invariants is largely successful, there is in particular one parameter that is not invariant between life histories: the asymptotic size (maximum size) of individuals in the population. This parameter plays the role of a master trait that characterizes most of the variation between life histories.


2020 ◽  
Vol 36 (1) ◽  
pp. 187-204
Author(s):  
Lesley Rees ◽  
◽  
Vanessa Shaw ◽  
Leila Qizalbash ◽  
Caroline Anderson ◽  
...  

AbstractThe nutritional prescription (whether in the form of food or liquid formulas) may be taken orally when a child has the capacity for spontaneous intake by mouth, but may need to be administered partially or completely by nasogastric tube or gastrostomy device (“enteral tube feeding”). The relative use of each of these methods varies both within and between countries. The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric renal dietitians and pediatric nephrologists, has developed clinical practice recommendations (CPRs) based on evidence where available, or on the expert opinion of the Taskforce members, using a Delphi process to seek consensus from the wider community of experts in the field. We present CPRs for delivery of the nutritional prescription via enteral tube feeding to children with chronic kidney disease stages 2–5 and on dialysis. We address the types of enteral feeding tubes, when they should be used, placement techniques, recommendations and contraindications for their use, and evidence for their effects on growth parameters. Statements with a low grade of evidence, or based on opinion, must be considered and adapted for the individual patient by the treating physician and dietitian according to their clinical judgement. Research recommendations have been suggested. The CPRs will be regularly audited and updated by the PRNT.


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