A mechanism for swarming in the tunicate Salpa thompsoni (Foxton, 1961)

2001 ◽  
Vol 13 (3) ◽  
pp. 240-245 ◽  
Author(s):  
M.C. Daponte ◽  
F.L. Capitanio ◽  
G.B. Esnal
Keyword(s):  
Growth Rate ◽  
The Body ◽  
Optimal Conditions ◽  
Population Densities ◽  
Oocyte Maturity ◽  
Solitary Individual ◽  
Mean Size ◽  
The Mean ◽  
Two Populations ◽  
Parent Ratio

Two populations of Salpa thompsoni, collected from the Weddell–Scotia confluence area at the end of two summers (1994 and 1995) with contrasting densities, are compared. The present study was aimed at corroborating whether fluctuations in abundance could be related to some life history parameters considered as indicators of growth rate in salp populations, such as the body size of solitary reproductive individuals, number of buds per block or chain in the stolon, and the offspring to parent ratio. No differences were observed in the sizes reached by aggregate individuals, or in the size at which oocyte maturity was attained (moment at which the development of the embryo can be detected). There were no differences in the size reached by the embryos during their residence inside the mother's blastozooid. In 1995, the percentage of non-fecundated blastozooids (which included even the largest individuals) was higher than in 1994. The mean size of the solitary individuals was significantly higher in 1994 than in 1995. The number of buds per block was also significantly higher in most of the stages, confirming that this is the mechanism used by these organisms to produce swarms. This species eventually attains high population densities under favorable environmental conditions such as poor sea-ice cover in winter. Under optimal conditions, the number of potential descendants produced by a single solitary individual would exceed 800.

scholarly journals Density and Size Distribution of the Sea Cucumber, Holothuria scabra (Jaeger, 1935), at Six Exploited Sites in Mahout Bay, Sultanate of Oman

2007 ◽  
Vol 12 ◽  
pp. 43 ◽  
Author(s):  
Khalfan M. Al-Rashdi ◽  
Michel R. Claereboudt ◽  
Saud S. Al-Busaidi
Keyword(s):  
Size Distribution ◽  
Sea Cucumber ◽  
Size Distributions ◽  
Sultanate Of Oman ◽  
Population Densities ◽  
Sea Cucumbers ◽  
Holothuria Scabra ◽  
Mean Size ◽  
Males And Females ◽  
The Mean

A rapid survey of the density and size distribution of recently exploited populations of Holothuria scabra in Mahout Bay (Ghubbat Hashish Bay) was carried out at six fishing sites. The results showed that population densities varied between 1170 and 4000 individuals ha-1 and biomass ranged between 393 and 2903 kg ha-1. The mean size of sea cucumbers and population densities were much lower in populations closer to human settlements, suggestive of overfishing. The sex ratio was estimated to be 1:1 and the size distributions of males and females did not differ significantly. The length-weight relationship for both sexes was calculated as W (g) = 0.033 Length (mm) 2.178. 

Fleece shedding, staple length and fleece weight in experimental Wiltshire Horn-Scottish Blackface sheep crosses

1959 ◽  
Vol 53 (2) ◽  
pp. 209-223 ◽  
Author(s):  
John Slee
Keyword(s):  
Growth Rate ◽  
The Body ◽  
Day Length ◽  
Average Growth Rate ◽  
Average Growth ◽  
Wool Production ◽  
Crossing Experiment ◽  
The Mean ◽  
Fleece Weight ◽  
Staple Length

1. A crossing experiment was carried out between two breeds of sheep: the Wiltshire Horn—a breed with a short-stapled fleece which is normally shed both in lambs and adults, and the Scottish Blackface—which has a long-stapled carpet type of fleece. Animals of F1, F2 and both backcross generations were studied for gross characteristics of the fleece.2. The influence of the Wiltshire genotype caused a high incidence of fleece-shedding animals amongst all the crosses. Three separate components of the shedding process were distinguished: (a) the ability to shed, (b) the extent of shedding—or proportion of the body area denuded, (c) the time of onset of shedding. Attributes (a) and (b) were determined genetically; control was probably on a multifactorial basis, although there may have been fewer genes involved than for the other characters studied. Given the genetically determined existence of (a) and (b), (c) was apparently controlled by the environment. Seasonal change in day length was postulated as a major operative factor.3. The mid-side staple length of Wiltshire crosses was less than that of the Blackface parents. The decrease resulted partly from shedding and partly also from a reduction in the average growth rate of some fibres. When corrected for shedding the mean staple lengths of the crosses were about equal to the values theoretically expected on the basis of multifactorial inheritance without directional dominance.4. The mean fleece weight of the Wiltshire crosses was less than that of the Blackface parents, due, about equally, to: (a) loss of wool by fleece shedding, (b) reduced wool production—probably caused, at least partly, by the decreased average growth rate of some of the component fibres of the fleece. Differences in wool production appeared to be inherited multifaetorially.

scholarly journals Growth rate and haploidization of Aspergillus niger on medium containing p-fluorophenylalanine

1968 ◽  
Vol 12 (3) ◽  
pp. 305-315 ◽  
Author(s):  
Pol Lhoas
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Growth Curves ◽  
Dry Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Complete Medium ◽  
Acid Analogue ◽  
Mean Size ◽  
The Mean

1. The comparison of the dry weight of thin layer haploid and diploid colonies of A. niger on complete medium and complete medium supplemented with p-fluoro-phenylalanine led to the conclusion that there is a difference in growth rates of hyphae under these different conditions.2. The growth curves of the same strains on both media were established. On complete medium, haploids and diploid show a growth rate increasing linearly for about 20 h after germination and reaching a maximum which is then maintained. On p-fluorophenylalanine, the haploids show a similar curve, although the maximum growth rate reached and maintained is about half that on complete medium; for the diploid, however, the maximum is less than the corresponding one in the haploid and, once this maximum has been reached, the growth rate goes down linearly to a very low value which is then maintained.3. The cytological study of the hyphal tip cell showed, in the presence of the amino acid analogue, a reduction of the mean size of the diploid nuclei together with an increase of the number of nuclear fragments. This explains the growth rates observed and is accepted as a confirmation that p-fluorophenylalanine, by its action on the mitosis, favours chromosome losses which lead finally to the production of haploid nuclei.

scholarly journals The effects of environmental temperature on the growth and metabolism of pigs given different amounts of food

1971 ◽  
Vol 25 (2) ◽  
pp. 259-272 ◽  
Author(s):  
M. F. Fuller ◽  
A. W. Boyne
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Live Weight ◽  
The Body ◽  
Effect Of Temperature ◽  
Daily Growth ◽  
Daily Food Intake ◽  
N Retention ◽  
Daily Food ◽  
The Mean

1. Twelve castrated male pigs were kept at each of three temperatures and given food at one of three levels of intake. The temperatures and daily food intakes (expressed as g/kg0.73) were 23° (80, 100, 120), 13° (100, 120, 140), 3–5° (120, 140, 160). Growth and nitrogen metabolism were measured during growth from 20 kglive weight until slaughter at gokg live weight, when the body contents of N and fat were estimated.2. Growth rate increased with each unit of daily food intake (I g/kg0.73 live weight) by 7.73 ± 0.74 g/d. This value did not vary significantly with temperature. Daily growth rate was depressed by 17.8 ± 2.3 g for each I° fall of temperature.3. Daily N retention estimated by the balance method exceeded by 2.59 g/d that estimated by the comparative slaughter technique. Both results led to the same conclusion, which echoed that found with growth rate, that there was no significant effect of temperature on the response of N retention to increasing food intake. Taking the mean of the two estimates, N retention at a constant food intake fell by 0.38±0.055 g/d for each I° fall of temperature.4. The N content of the ingesta-free carcass at slaughter fell with each increase in daily food intake by 0.007±0.002%, and the fat content rose correspondingly by 0.116±0.027%. These regressions did not vary significantly with temperature. When considered at a constant food intake, body composition did not alter significantly with temperature.

scholarly journals Sphaeridiotrema globulus (Rudolphi, 1814) (Digenea): evidence for two species known under a single name and a description of Sphaeridiotrema pseudoglobulus n.sp.

1993 ◽  
Vol 71 (4) ◽  
pp. 700-707 ◽  
Author(s):  
J. Daniel McLaughlin ◽  
Marilyn E. Scott ◽  
Jane E. Huffman
Keyword(s):  
New Jersey ◽  
Egg Size ◽  
Anterior Testis ◽  
The Body ◽  
Internal Organs ◽  
Posterior Testis ◽  
Mean Size ◽  
Basal Bulb ◽  
The Mean ◽  
A New Species

Experimental infection of domestic ducklings with metacercariae believed to be those of Sphaeridiotrema globulus from snails in Quebec, Canada, and New Jersey, U.S.A., revealed that there are two species known under this name. Study of museum specimens has confirmed that the New Jersey specimens represent the original S. globulus: the specimens from Quebec represent a new species. The two species can be separated reliably on the basis of egg size: S. globulus (New Jersey) has smaller eggs (mean 97 ± 4 (SD) μm; range 91–108 μm) than S. pseudoglobulus n.sp. from Quebec (mean 116 ± 5 μm: range 103–125 μm). The cirrus in S. pseudoglobulus has a basal bulb not found in that of S. globulus. There are fewer uterine coils anterior to the acetabulum in S. pseudoglobulus. Comparison of 6-day-old populations of each species revealed several statistically significant differences in the mean size of internal organs. The overall sizes of the body, ovary, and eggs and the width of the posterior testis were greater in S. pseudoglobulus: the pharynx, length of the posterior testis, and number of eggs in the uterus were greater in S. globulus. No differences were found in the size of the oral sucker, acetabulum, or anterior testis.

Predictors of bone maturation, growth rate and adult height in children with central precocious puberty treated with depot leuprolide acetate

2018 ◽  
Vol 31 (6) ◽  
pp. 655-663 ◽  
Author(s):  
Karen O. Klein ◽  
Sanja Dragnic ◽  
Ahmed M. Soliman ◽  
Peter Bacher
Keyword(s):  
Growth Rate ◽  
Precocious Puberty ◽  
Adult Height ◽  
Central Precocious Puberty ◽  
Bone Age ◽  
The Body ◽  
Bone Maturation ◽  
Maturation Rate ◽  
Parental Height ◽  
The Mean

Abstract Background: Children with central precocious puberty (CPP) are treated with gonadotropin-releasing hormone agonists (GnRHa) to suppress puberty. Optimizing treatment outcomes continues to be studied. The relationships between growth, rate of bone maturation (bone age/chronological age [ΔBA/ΔCA]), luteinizing hormone (LH), predicted adult stature (PAS), as well as variables influencing these outcomes, were studied in children treated with depot leuprolide (LA Depot) Methods: Subjects (64 girls, seven boys) with CPP received LA Depot every 3 months for up to 42 months. Multivariate regression analyses were conducted to examine the predictors affecting ΔBA/ΔCA, PAS and growth rate. Results: Ninety percent of subjects (18 of 20) were suppressed (LH levels <4 IU/L) at 42 months. Over 42 months, the mean growth rate declined 2 cm/year, the mean BA/CA ratio decreased 0.21 and PAS increased 8.90 cm for girls (n=64). PAS improved to mid-parental height (MPH) in 46.2% of children by 30 months of treatment. Regression analysis showed that only the Body Mass Index Standardized Score (BMI SDS) was significantly associated (β+0.378 and +0.367, p≤0.05) with growth rate. For PAS, significant correlations were with MPH (β+0.808 and +0.791, p<0.001) and ΔBA/ΔCA (β+0.808 and +0.791, p<0.001). For ΔBA/ΔCA, a significant association was found only with BA at onset of treatment (β−0.098 and −0.103, p≤0.05). Peak-stimulated or basal LH showed no significant influence on growth rate, ΔBA/ΔCA or PAS. Conclusions: Growth rate and bone maturation rate normalized on treatment with LA Depot. LH levels were not significantly correlated with growth rate, ΔBA/ΔCA or PAS, suggesting that suppression was adequate and variations in gonadotropin levels were below the threshold affecting outcomes.

scholarly journals The influence of carboxymethylcellulose, xanthan and guar-gum addition in bread dough before freezing on metabolism and viability of Saccharomyces cerevisiae

2009 ◽  
pp. 211-220
Author(s):  
Dusanka Pejin ◽  
Olgica Grujic ◽  
Jelena Pejin ◽  
Irena Dosenovic ◽  
Suncica Kocic-Tanackov
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Growth Rate ◽  
Specific Growth Rate ◽  
Guar Gum ◽  
Specific Growth ◽  
Living Cells ◽  
Optimal Conditions ◽  
Intact Cells ◽  
Respiration Intensity ◽  
The Mean

Doughs were prepared with different concentrations of carboxymethylcellulose, xanthan, and guar-gum (0.1, 0.2 and 0.3% in doughs), freezed at -20?C and analyzed after 0, 7, 15 and 30 days. Pure Saccharomyces cerevisiae culture was isolated from dough and was cultivated under optimal conditions during 24 hrs to determine the following parameters: specific growth rate, fermentative activities and cytochromes contents in intact cells with the aim of determining the respiration intensity. During freezing of dough for 30 days, the percentage of living cells from dough surface was 53.11% and from the middle 54.95%. Carboxymethylcellulose in concentration of 0.3 and 0.5% increased number of survived cells on the surface to 70.64, and 70.28% and in the middle to 74.79, and 76.54%, respectively. Guar-gum increased number of survived cells only in concentration of 0.1% on the surface to 70.17% and in the middle of the dough to 75.26%. The mean specific growth rate decreased by approximately 10% during 30 days of storage at -20?C. Content of cytochromes in intact cells decreased in all samples during freezing.

Changes in thyroid activity of Ambystoma gracile (Baird) during different larval, transforming, and postmetamorphic phases

1978 ◽  
Vol 56 (6) ◽  
pp. 1377-1381 ◽  
Author(s):  
G. W. Eagleson ◽  
B. A. McKeown
Keyword(s):  
High Altitude ◽  
Thyroid Activity ◽  
Gradual Rise ◽  
Serum Thyroxine ◽  
Thyroxine Level ◽  
Laboratory Conditions ◽  
Metamorphic Climax ◽  
Mean Size ◽  
The Mean ◽  
Two Populations

Thyroid activity for two populations of Ambystoma gracile acclimated to laboratory conditions was assessed by thyroid radioiodide (125I) uptake and serum thyroxine level determined by radioimmunoassay. Both populations exhibited a gradual rise in thyroid activity preceding the mean size for metamorphosis. Larval and transformed salamanders also exhibited a decline in thyroid activity following attainment of this mean size, and this decline was observed for both transformed and neotenous animals. Thyroid activity and serum thyroxine levels were greatest during metamorphic climax. Neoteny was attributed to the generally lower thyroid activity preceding the mean size for metamorphosis which was observed for the high altitude population (having greater neotenic tendencies).

The incidence of central serous chorioretinopathy in the population of Kazan: Results of a retrospective epidemiological analysis for 2009–2018

2020 ◽  
pp. 30-33
Author(s):  
D. R. Аgliullin ◽  
G. R. Khasanova ◽  
E. A. Abdulaeva ◽  
S. T. Agliullina ◽  
A. N. Amirov ◽  
...  
Keyword(s):  
Growth Rate ◽  
Central Serous Chorioretinopathy ◽  
Morbidity Rate ◽  
Seasonal Prevalence ◽  
Upward Trend ◽  
Epidemiological Analysis ◽  
Significant Upward Trend ◽  
Track Record ◽  
Minimum Age ◽  
The Mean

Objective: To assess the incidence of central serous chorioretinopathy (CSC) through the example of a large industrial Russian city.Methods: A retrospective analysis of CSC of Kazan population for 2009–2018 has been done.Results: From 2019 to 2018, 831 new cases of CSC were registered in Kazan. A statistically significant upward trend with growth rate 105.2% and accession rate 5.2% was typical for the annual track record. The mean age of patients was 50 years, the minimum age was 14 years, the maximum age was 87 years. A statistically significant upward trend was detected in track record of incidence in groups of 30–39-year-old and 40–49-year-old. Seasonal increase of the incidence was recorded in February, March, April, October, and November.Conclusions: The upward trend and seasonal prevalence are typical for longterm morbidity of CSC in Kazan. The highest morbidity rate of CSC and statistically significant upward trend of its incidence in track record were recorded in the age of 30–39. 

Evaluation of Salivary Antioxidants and Oxidative Stress Markers in Male Smokers

2019 ◽  
Vol 22 (7) ◽  
pp. 496-501
Author(s):  
Fatemeh Ahmadi-Motamayel ◽  
Parisa Falsafi ◽  
Hamidreza Abolsamadi ◽  
Mohammad T. Goodarzi ◽  
Jalal Poorolajal
Keyword(s):  
Oxidative Stress ◽  
Uric Acid ◽  
Free Radicals ◽  
Antioxidant Capacity ◽  
Cigarette Smoke ◽  
Total Antioxidant Capacity ◽  
The Body ◽  
Total Antioxidant ◽  
The Mean ◽  
And Oxidative Stress

Background: Cigarette smoke free radicals can cause cellular damage and different diseases. All the body fluids have antioxidants which protect against free radicals. Objective: The aim of this study was to evaluate salivary total antioxidant capacity and peroxidase, uric acid and malondialdehyde levels in smokers and a nonsmoking control group. Methods: Unstimulated saliva was collected from 510 males. A total of 259 subjects were current smokers and 251 were non-smokers. The levels of salivary total antioxidant capacity, uric acid, peroxidase and malondialdehyde were measured using standard procedures. Data were analyzed with t test and ANOVA. Results: The smokers were younger and dental hygiene index was higher than healthy nonsmoking controls. The mean total antioxidant capacity in smokers and nonsmokers was 0.13±0.07 and 0.21±011, respectively (P=0.001). Smokers had significantly lower peroxidase and uric acid levels than healthy controls. In addition, the mean malondialdehyde levels in the smokers and nonsmokers were 4.55 ±2.61 and 2.79 ±2.21, respectively (P=0.001). Conclusion: Cigarette smoke produces free radical and oxidative stress, causing many side effects. Salivary antioxidant levels decreased and malondialdehyde levels increased in smokers, indicating the high oxidative stress among smokers compared to nonsmokers. Cigarette smoke had deleterious effects on main salivary antioxidants levels.

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