The use of growth curves to assess the crowding effect on procercoids of the tapeworm Triaenophorus crassus in the copepod host Cyclops bicuspidatus thomasi

1985 ◽  
Vol 63 (10) ◽  
pp. 2343-2351 ◽  
Author(s):  
Allen W. Shostak ◽  
Ronald B. Rosen ◽  
Terry A. Dick
Keyword(s):  
Growth Rates ◽  
Natural Variation ◽  
Growth Curves ◽  
Fixed Time ◽  
Minimum Size ◽  
Crowding Effect ◽  
Average Volume ◽  
Growth Initiation ◽  
Accelerated Growth ◽  
Size Threshold

Richards growth curves were fitted to data from procercoids of Triaenophorus crassus (Pseudophyllidea) in experimentally infected Cyclops bicuspidatus thomasi (Copepoda). Average volume per procercoid varied inversely with intensity, and procercoids in female copepods were correspondingly larger than procercoids in males. The simple inverse relationship, which usually characterizes the crowding effect on cestode size, held for average procercoid growth rates, but the growth rates of differentiated and undifferentiated procercoids diverged at higher intensities. Three apparently intrinsic features of procercoid growth (initiation of differentiation at a fixed time, a minimum size threshold for differentiation, and an accelerated growth rate in procercoids following differentiation) provided a mechanism whereby natural variation in procercoid growth rates could be amplified to produce a parasite infrapopulation comprising large, differentiated procercoids and stunted, undifferentiated procercoids. Calculations using parameters of the fitted growth curves indicated that the hosts were probably under nutritional stress in low intensity infections during rapid growth of the differentiating and differentiated procercoids.

A STUDY OF RATES OF GROWTH OF YORKSHIRE, LACOMBE, LANDRACE, AND CROSSBRED PIGS FROM BIRTH TO 200 LB

1964 ◽  
Vol 44 (3) ◽  
pp. 315-319
Author(s):  
J. M. Bell
Keyword(s):  
Growth Rates ◽  
Early Life ◽  
Growth Curves ◽  
Rates Of Growth ◽  
Similar Growth ◽  
Crossbred Pigs

Growth records were obtained from 12 research establishments across Canada for pigs fed according to current (1960–63) recommendations of nutrition and management. Growth curves showing age in days and weight in pounds are presented for the various breeds and crossbreds, for between-station comparisons, for comparison of upper and lower quartiles in purebred pigs, and for comparison of growth rates of purebreds with that of Yorkshires of 20 to 25 years ago.Age at 200 lb averaged from 152 to 187 days, among 10 stations for the Yorkshire breed. Pigs of each of the pure breeds reached 200 lb about 3 weeks earlier than that indicated in previous studies. Crossbred pigs of each of four different crosses grew more rapidly than average Yorkshires, some reaching 200 lb in 140 days and having gains in excess of 2.3 lb/day during the finishing period. Yorkshire, Lacombe, and Landrace pigs had similar growth curves. The upper quartile averaged 1.8 and the lower 1.4 lb/day gain between 100 and 200 lb weights. Slow-maturing pigs tended to be below average throughout life but differences in maturity between stations seemed to reflect differing rates of gain in early life, since finishing period gains were similar in 8 of 10 stations.

Age, growth and sex determination in a population of smooth snakes, Coronella austriaca in southern England

2004 ◽  
Vol 25 (2) ◽  
pp. 137-150 ◽  
Author(s):  
Keyword(s):  
Sex Determination ◽  
Age Structure ◽  
Growth Rates ◽  
Growth Curves ◽  
Tail Length ◽  
Daily Growth ◽  
Southern England ◽  
The Difference ◽  
The Relationship ◽  
Coronella Austriaca

AbstractBetween 1992-2001 a study of individually marked smooth snakes Coronella austriaca was done in Wareham Forest, southern England. The sex of individual snakes was determined using the relationship between tail length and snout-vent length, and the presence/absence of a hemi-penes swelling at the base of the tail. Males had longer tails than females at all ages/sizes and the difference between the sexes increased with increasing snout-vent length. Using multiple captures of known individuals over many years, size related daily growth rates were determined for each sex that enabled growth curves to be produced. The age structure of the population was determined for each complete year of the study. Very few young small snakes were captured each year. Of all the females who were potentially able to breed, only the oldest, and therefore largest, did so.

scholarly journals The demographics and morphometries of biogenic reefs: important considerations in conservation management

2017 ◽  
Vol 98 (6) ◽  
pp. 1231-1240 ◽  
Author(s):  
Jenna M. Brash ◽  
Robert L. Cook ◽  
Clara L. Mackenzie ◽  
William G. Sanderson
Keyword(s):  
Population Structure ◽  
Growth Rates ◽  
Conservation Management ◽  
Tidal Flow ◽  
Growth Curves ◽  
Shell Morphology ◽  
Published Data ◽  
Marine Habitat ◽  
Juvenile Abundance ◽  
Horse Mussel

Modiolus modiolus L. (horse mussel) reefs are a priority marine habitat of high conservation value that is currently listed as endangered and/or threatened across its European distribution. Population structure, density or shell morphology may influence the biodiversity of a reef, either directly or indirectly. Thus, such metrics are important considerations for successful conservation management of these biodiversity hotspots. Population structure, shell morphology and growth rates were examined in M. modiolus reefs across the UK range of the habitat to examine differences between key populations, including those near the Lleyn Peninsula in Wales (southern range), off Port Appin in Western Scotland (mid-range) and in Scapa Flow in the Orkney Isles, Scotland (northern range). Additionally, the influence of physical conditions (temperature and tidal flow) to growth rate and predicted maximum shell length for each population was examined. Growth rates were determined using acetate peels of sectioned shells. Lower juvenile abundance was observed in Scapa Flow. Small, narrow-shaped shells were found to be characteristic of North Lleyn mussels, and larger, globular-shaped shells were characteristic of mussels in Scapa Flow and off Port Appin. Mussels in Scapa Flow were slower growing, yet reached a longer asymptotic length (L∞) than mussels of Port Appin and North Lleyn. Growth curves from sites within this study were analysed with other published data. A trend of higher L∞ at higher latitudes and at lower flow rates was observed. Variations in growth and age are discussed in relation to flow regimes, connectivity to other reefs, density and latitude.

Interrelations in the growth and development of Lolium. I. Some effects of vernalization on growth and development

1965 ◽  
Vol 16 (6) ◽  
pp. 903 ◽  
Author(s):  
JH Silsbury
Keyword(s):  
Low Temperature ◽  
Growth Rates ◽  
Growth And Development ◽  
Growth Curves ◽  
High Growth ◽  
Reproductive Development ◽  
Controlled Environment ◽  
Lolium Rigidum ◽  
Vegetative Phase ◽  
Reproductive Phase

The responses of Lolium rigidum Gaud. and L. perenne L. to low temperature seed vernalization were determined by comparing the growth and development of vernalized and unvernalized plants raised in the field and in a controlled environment cabinet. Vernalization did not appear to influence growth in the vegetative phase, but usually induced earlier heading and a greater proportion of reproductive tillers. Comparisons of vernalized (reproductive) and unvernalized (vegetative) plants show increased reproductive development to be associated with higher growth rates, lower tillering, and greater weight per tiller. High growth rates during the reproductive phase are considered to be due to the ability of reproductive tillers to grow more rapidly than vegetative tillers through the growth of true stem functioning as a "sink" for assimilate. Generalized growth curves for vernalized and unvernalized ryegrass grown under long days are presented and discussed.

Experimental study of the stability of boundary-layer flow along a heated, inclined plate

1998 ◽  
Vol 367 ◽  
pp. 1-25 ◽  
Author(s):  
E. J. ZUERCHER ◽  
J. W. JACOBS ◽  
C. F. CHEN
Keyword(s):  
Boundary Layer ◽  
Growth Rates ◽  
Growth Curves ◽  
Leading Edge ◽  
Heated Plate ◽  
Inclined Plate ◽  
Double Pass ◽  
Longitudinal Vortices ◽  
Spatial Growth ◽  
Layer Flow

Experiments are conducted to study the longitudinal vortices that develop in the boundary layer on the upper surface of an inclined, heated plate. An isothermal plate in water is inclined at angles ranging from 20 to 60 degrees (from the vertical) while the temperature difference is varied from 2 to 23°C. A double-pass Schlieren system is used to visualize the vortices and particle image velocimetry (PIV) is used to measure velocities. In addition, a unique method is developed such that both the Schlieren visualization and PIV can be performed simultaneously. The wavelengths of the vortices and the critical modified Reynolds numbers (R˜) for the onset, merging, and breakup of the vortices are determined from Schlieren images for Pr=5.8. The critical values for R˜ and the critical wavelengths are compared to results of previous experiments and stability analyses. The spatial growth rates of vortices are determined by using the PIV measurements to determine how the circulation in the vortices grows with distance from the leading edge. This is the first time that the growth rate of the vortices have been found using velocity measurements. These spatial growth rates are compared to the results of Iyer & Kelly (1974) and found to be in general agreement. By defining a suitable circulation threshold, the critical R˜ for the onset of the vortices can be found from the growth curves.

Age structure and growth in a population of Pelobates varaldii (Anura, Pelobatidae) from northwestern Morocco

2011 ◽  
Vol 32 (4) ◽  
pp. 550-556 ◽  
Author(s):  
Marcello Mezzasalma ◽  
Fabio Maria Guarino ◽  
Angelica Crottini ◽  
Franco Andreone ◽  
Philip de Pous
Keyword(s):  
Body Mass ◽  
Age Structure ◽  
Growth Rates ◽  
Growth Curves ◽  
Von Bertalanffy ◽  
Growth Coefficient ◽  
Similar Profile ◽  
Spadefoot Toad ◽  
The Difference ◽  
First Time

AbstractAge structure and growth in the Moroccan spadefoot toad, Pelobates varaldii were estimated by skeletochronology and reported for the first time for a population living in NW Morocco. Snout vent length and body mass did not significantly differ between the sexes, although females appeared larger and heavier than males. Age ranged 2-7 years in males (mean age±SD: 4.5±1.2, n = 66) and 2-10 years in females (4.7±2.4, n = 20). The difference in age was not significant between the sexes. The modal age was 5 years for males and 3 years for females. The age distributions significantly differed between the sexes. Von Bertalanffy growth curves showed a similar profile between the sexes although growth coefficient was higher in males than in females. Longevity and growth rates of P. varaldii were compared with those of other species of the genus Pelobates.

Growth rates of four Hawaiian deep slope fishes: a comparison of methods for estimating age and growth from otolith microincrement widths

1997 ◽  
Vol 54 (1) ◽  
pp. 126-136 ◽  
Author(s):  
H A Williams ◽  
M K Lowe
Keyword(s):  
Growth Rates ◽  
Growth Curves ◽  
Age And Growth ◽  
Interval Length ◽  
Fish Length ◽  
Comparison Of Methods ◽  
Increment Width ◽  
Daily Increment ◽  
Minimum Number ◽  
Age Estimates

Two methods were used to estimate the age and growth of four Hawaiian deep slope fishes. Otolith daily increment width estimates from radial sections of sagittal otoliths were integrated over the otolith radius to approximate age by (i) dividing interval length (micrometres) by mean increment width (micrometres per day) and summing this quotient for consecutive 500- µm radial intervals (S. Ralston and H.A. Williams. 1989. Fish. Bull. 87: 1-16) and (ii) fitting increment width (y) versus otolith radius (x) to a Gompertz rate curve and calculating the inverse integral of this curve (M.K. Smith and E. Kostlan. 1991. Fish. Bull. 89: 461-472). The methods also differ in the way the age-length key is generated. Ralston and Williams' method uses integrated age versus a regression-based estimate of fish length at 500- µm otolith radial intervals; Smith and Kostlan's method uses estimated age versus actual fish length. Neither method of integration produced significantly different age estimates; however, the use of regression-based fish length estimates instead of sampled fish lengths resulted in significant differences between estimated growth curves. The minimum number of daily increment width estimates required as a function of otolith radius was calculated, on the basis of observed microincrement width variation.

scholarly journals Modeling growth of mandibles in the Western Arctic caribou herd

Rangifer ◽  
2001 ◽  
Vol 21 (1) ◽  
pp. 29 ◽  
Author(s):  
Jay M. Ver Hoef ◽  
Patrick Valkenburg ◽  
James R. Dau
Keyword(s):  
Maximum Likelihood ◽  
Nonlinear Model ◽  
Growth Rates ◽  
Compensatory Growth ◽  
Growth Curves ◽  
Likelihood Ratio Tests ◽  
Maximum Likelihood Estimates ◽  
Western Arctic ◽  
The 1960S ◽  
Modeling Growth

We compared growth curves for ramus length and diastema length from two autumn collections of mandibles of male Western Arctic Herd caribou in Alaska. We were primarily interested in determining if growth curves of caribou mandibles differed between caribou born during 1959-1967, after the herd had been high for several years and was probably declining in size, and those born during 1976-1988, when the herd was increasing in size. To compare these growth curves, we used a nonlinear model and used maximum likelihood estimates and likelihood ratio tests. We found that growth rates were similar between periods, but intercepts and variances of growth curves differed. From this we infer that calves were smaller in autumn during the 1960s and that significant compensatory growth did not occur later in life.

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