Données préliminaires sur la taille, la croissance et la longévité du varan du Nil (Varanus niloticus) dans la région du lac Tchad

1994 ◽  
Vol 72 (2) ◽  
pp. 262-273 ◽  
Author(s):  
Vivian de Buffrénil ◽  
Claire Chabanet ◽  
Jaques Castanet
Keyword(s):  
Growth Rate ◽  
Age Structure ◽  
General Model ◽  
Tail Length ◽  
Large Species ◽  
Age Classes ◽  
Total Length ◽  
Asymptotic Size ◽  
The Difference ◽  
The Relationship

A sample of 288 Nile varanids, including only adults and subadults (153 males and 135 females), was collected in the Tchadian part of Lake Tchad where the species is regularly exploited. Each animal was measured (L, total length; MC, snout–vent length) and weighed, and its age was determined by the skeletochronological technique. No information of this sort, collected on a wide sample, was hitherto available. For the age-classes studied, the most representative sizes in the population (the medians being considered) were close to 155 cm for males and 134 cm for females, with respective masses of about 5 and 3 kg. The difference between sexes was highly significant. Conversely, age structure in the samples were not significantly different among sexes (except for one age-class: 4 years). The longevity of these lizards is about 8 years in the Lake Tchad region. The relationship between tail length and snout–vent length shows similar tendencies in both sexes (Q = 1.06MC + 21.48). The tail becomes proportionally shorter with growth. Both sexes also display similar tendencies for the relationship between total length and mass (M = 8.131E − 9L3.992 − 8.131E − 9(213..992) + 0.034). Body growth in the Nile varanids corresponds to a model derived from Von Bertalanffy's general model: L = K(1 − e−b(age)) + a. Growth of males is faster and steadier than that of females. Males reach their asymptotic size (207 cm) at a later age (9 years) than the females (154.8 cm reached at age 6 years). Though comparative data are very scarce, the growth rate in the animals examined seems high compared with that of other large species of varanids, especially Varanus komodoensis.

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 Assessing the accumulated stickiness magnitude from fabric–skin friction: effect of wetness level of various fabrics

2018 ◽  
Vol 5 (8) ◽  
pp. 180860 ◽  
Author(s):  
Ka-Po Maggie Tang ◽  
Kam-Hong Chau ◽  
Chi-Wai Kan ◽  
Jin-tu Fan
Keyword(s):  
Growth Rate ◽  
Recovery Period ◽  
Skin Surface ◽  
Cotton Fabrics ◽  
Surface Geometry ◽  
Intimate Apparel ◽  
Fixed Stimulus ◽  
Skin Wetness ◽  
The Difference ◽  
The Relationship

Increasing skin wetness tends to increase fabric–skin adhesion and friction, resulting in wear discomfort or skin injuries. Here, the magnitude estimation approach was used to assess the stickiness sensation perceived in fabrics. Seven fabric types were wetted by putting onto wet ‘skin’ surface and dried for different durations to achieve different wetness levels, simulating wearing conditions during the recovery period after sweating. Results showed that the relationship between magnitude estimates of stickiness and amount of water present in fabric demonstrated a power function. The exponents and constant from power regression show the growth rate of stickiness sensation with moisture intensity and the perceived stickiness under fixed stimulus intensity, respectively. A novel parameter, accumulated stickiness magnitude (ASM), describing how much discomfort a wetted fabric offered throughout the drying period, was developed. Thin cotton fabrics (fabric W01 and W03), having higher saturation level after contacting with wetted skin surface, arouse stronger stickiness feeling and their ASM is remarkably higher. The difference in stickiness estimates is due to the difference in chemical composition and surface geometry. This study suggests us the way to predict perceived stickiness in fabrics with different wetness levels which is useful for applications like sportswear, intimate apparel or healthcare products.

Trophic Structure, Reproductive Success, and Growth Rate of Fishes in a Natural and Modified Headwater Stream

1982 ◽  
Vol 39 (7) ◽  
pp. 968-978 ◽  
Author(s):  
Isaac J. Schlosser
Keyword(s):  
Growth Rate ◽  
Reproductive Success ◽  
Flow Regime ◽  
Age Structure ◽  
Trophic Structure ◽  
Headwater Stream ◽  
Organic Substrates ◽  
Age Classes ◽  
Younger Age ◽  
The Impact

The impact of removing riparian vegetation, channel straightening, and fluctuations in flow regime on trophic structure, reproductive success, and growth rate of fishes was assessed in a natural (Jordan Creek (JC)) and modified (Big Ditch (BD)) headwater stream in east-central Illinois. Shallow habitats and organic substrates increased more in BD than JC during low flow periods in summer. Insect densities in JC were highest in late spring, declining to low levels by late summer. Insect densities in BD were high throughout summer. Fish in JC were predominantly benthic insectivores and insectivore–piscivores; trophic structure, age structure, and biomass were stable between years and seasons; recruits made up a small and stable portion of community biomass and were primarily insectivore–piscivores and generalized insectivores; younger age-classes were in shallow riffle habitats. Adult fish and recruits in BD were predominantly generalized insectivores, omnivores, and herbivore–detritivores; the last two were primarily mid-river species (Carpoides cyprinus and Dorosoma cepedianum). Considerable seasonal and annual variation in trophic structure, total biomass, and age structure occurred in BD associated with annual fluctuations in flow regime, abundance of organic substrates, and reproductive success of mid-river species. Younger age-classes had higher summer growth rates in BD than JC. The temporally variable physical environment and unstable autotrophic energy base created in modified headwater streams are probably major factors responsible for recent shifts in large river fish communities in the midwestern United States from insectivore and insectivore–piscivore species to omnivores and herbivore–detritivores.Key words: community organization, fishes, Illinois, stream continuum, stream alteration, trophic ecology, warmwater stream

scholarly journals Relationship between sexual signals and louse (Insecta: Phthiraptera) infestation of breeding and migrating Barn swallows (Hirundo rustica) in Hungary

2012 ◽  
Vol 20 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Enikő Gál ◽  
Tibor Csörgő ◽  
Zoltán Vas
Keyword(s):  
Breeding Season ◽  
Tail Length ◽  
Significant Negative Correlation ◽  
Breeding Birds ◽  
Hirundo Rustica ◽  
Louse Infestation ◽  
Physical Interactions ◽  
Barn Swallows ◽  
The Difference ◽  
The Relationship

Abstract Lice (Phthiraptera) chew characteristic holes on the remiges and rectrices of Barn swallows (Hirundo rustica). The number of these holes correlate positively with the intensity of louse infestation, hence hole counts are useful to quantify lousiness. Several papers showed that lice affect both life expectancy and reproductive success of hosts. In male Barn swallows, the length of the outermost tail feathers act as a sexual signal. Females prefer long-tailed males, which have significantly fewer feather holes. In this study we sampled breeding and migrating Barn swallows and compared their louse burden, and the relationship between tail length and the number of feather holes. We found significant negative correlation between feather holes and tail length in breeding males; however, we found non-significant correlation in migrating males. We suggest that attractive males have more physical interactions (e.g. extra-pair copulation) during the breeding season, than less attractive males, hence they are more exposed to louse transmission, and therefore the difference in the infestation declines towards the end of the breeding season. However, given that migrating swallow groups include colonial and solitary breeding birds, it cannot be excluded that a potentially different louse distribution on solitary breeding birds may contribute to the results.

scholarly journals DAMPAK KEPENDUDUKAN TERHADAP PEMUKIMAN

Populasi ◽  
2016 ◽  
Vol 2 (2) ◽  
Author(s):  
Muhadjir Darwin
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Economic Condition ◽  
Housing Stock ◽  
High Rate ◽  
Household Members ◽  
The Difference ◽  
The Relationship ◽  
Human Problem

Housing and its sanitation has been widely recognized as a global human problem. Apart of the sources of problem is population, i.e high rate of population growth and over urbanization. Using the Indonesian case, this paper discusses the relationship between population and housing. The population growth rate of Indonesia declined from 2.3 annually during the decade of 1971- 1980 to 1.97 annually during the next decade. However, the average number of household members declined from 4.9 to 4.5 during the same period. As a result, the number of households increased substantially than the number of population. This phenomenon will affect the increase of the need of housing. In the meantime, the economic condition of Indonesian households could not compete with the soaring prices of housing. In addition, government capabilities to provide housing for the society are still very limited. The data available shows the evidence onthe scarcity of housing,where the number of housing stock is smaller than the number of households. However, The number of housing stock has increased substantially, whereas the difference between the number of households and the number of housing stock decreased consistently. These data indicate that productivity of housing market, particularly the informalone, isconsiderably high, even thoughinreality the qualityof suchhousing is, ingeneral, low.

The performance of short scrotum and wether lambs born in winter or spring and run at pasture in northern Tasmania

1990 ◽  
Vol 30 (2) ◽  
pp. 165 ◽  
Author(s):  
DL Hopkins ◽  
KD Gilbert ◽  
KL Saunders
Keyword(s):  
Growth Rate ◽  
Carcass Weight ◽  
Research Station ◽  
High Fat ◽  
The Difference ◽  
Fat Score ◽  
The Relationship ◽  
Poor Relationship

Summary. The growth of short scrotum and wether lambs was studied in 3 experiments over 2 years, at the Elliott Research Station in northern Tasmania. Short scrotum lambs born in winter grew significantly (P<0.05) faster than wethers from birth to slaughter at 137 days of age. For spring born, short scrotum lambs, the growth advantage was less because of the quality and quantity of pasture available during summer and autumn. Wether lambs were fatter than short scrotum lambs in all experiments, with the slope of the relationship between GR and carcass weight being 0.57 � 0.02 I! 0.42 � 0.01 mmkg (experiment 1); 1.13 � 0.1 1 v. 0.68 � 0.09 mm/kg (experiment 2); and 0.91 � 0.16 v. 0.63 � 0.08 mm/kg (experiment 3) respectively. As carcass weight increased, the difference in carcass fatness increased. There was a shift in the distribution of carcasses according to fat score, with more wether carcasses being allocated high fat scores. Testes weight in the short scrotum lambs showed considerable variation within and between experiments and in all cases the testes were located in a subcutaneous position. There was a poor relationship between testes weight and growth rate. The level of testes development in a proportion of animals indicated that the animals could be fertile.

Growth and development of Strongyloides venezuelensis Brumpt, 1934 in the albino rat

Parasitology ◽  
1970 ◽  
Vol 61 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Guta Wertheim
Keyword(s):  
Growth Rate ◽  
Developmental Stage ◽  
Growth And Development ◽  
Tail Length ◽  
Albino Rats ◽  
Body Width ◽  
Albino Rat ◽  
Adult Females ◽  
Strongyloides Venezuelensis ◽  
The Difference

Growth and development of S. venezuelensis in percutaneously infected albino rats was studied and compared with S. ratti. The development of S. venezuelensis was found to last longer than that of S. ratti, the difference resulting mainly from the longer sojourn of the L3 larvae in skin and lungs. The growth rate was found to differ in each developmental stage, being higher in L4 than in L3 larvae. The adult females continued to increase in size for 6–7 days postexposure. The increase in body width, oesophagus length and tail length was found to be allometric bradyauxetic.

scholarly journals Unemployment and Growth in the Tourism Sector in Mexico: Revisiting the Growth-Rate Version of Okun’s Law

Economies ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 83
Author(s):  
Sánchez López
Keyword(s):  
Growth Rate ◽  
Economic Crisis ◽  
Okun’S Law ◽  
Okun's Law ◽  
Tourism Sector ◽  
The Difference ◽  
The Relationship

In this paper, we analyze, by means of the difference version of Okun’s law, the relationship between tourism sector growth and unemployment in Mexico during the period 2000Q2–2018Q4. The results show that tourism growth is a palliative for unemployment, whereas unemployment reduces the growth of the tourism sector. The results also show that the relationship between the mentioned variables becomes stronger during an economic crisis and weaker during expansion periods.

The influence of season and nutrition on the sulphur content of wool from Merino and Cheviot sheep

1968 ◽  
Vol 70 (2) ◽  
pp. 111-116 ◽  
Author(s):  
J. M. Doney ◽  
C. C. Evans
Keyword(s):  
Growth Rate ◽  
Nutrient Intake ◽  
Sulphur Content ◽  
Nutrient Cycle ◽  
Wool Growth ◽  
Seasonal Depression ◽  
The Difference ◽  
Cycle Group ◽  
The Relationship ◽  
Annual Amount

SUMMARYSulphur content, expressed as a percentage of clean dry wool weight, was measured at monthly intervals in two breeds of sheep, Cheviot and Merino x Cheviot backcross (¾ Merino, ¼ Cheviot), offered an equivalent annual amount of feed in three ways—constant level, natural grazing cycle and reversed grazing cycle. The relationships between S content and wool growth rate or nutrient intake differed with both breed and nutrient cycle, but all the results could be explained satisfactorily on the basis of a constant optimum composition for each individual with sulphur impoverishment related to lack of balance between follicle activity rate and high-S substrate availability.The difference in mean maximum S content between breeds (3·87% and 3·81% for Cheviot and ‘Merino’ respectively) was much smaller than the difference between individuals within the breeds (4·05·3·72% and 3·92·3·66%). The seasonal depression within individuals varied with nutrition and wool growth rate, Cheviot sheep showing the greatest depression and lowest values (2·89 and 3·28% for Cheviot and 'Merino, respectively in the reversed cycle group). There was no consistent seasonal trend in the relationship between clean and unscoured wool weight.

The Population Age Structure of Spotted Knapweed (Centaurea maculosa) in Montana

Weed Science ◽  
1987 ◽  
Vol 35 (2) ◽  
pp. 194-198 ◽  
Author(s):  
Keith W. Boggs ◽  
Jim M. Story
Keyword(s):  
High Mortality ◽  
Age Structure ◽  
Secondary Xylem ◽  
Older Age ◽  
Centaurea Maculosa ◽  
Early Age ◽  
Spotted Knapweed ◽  
Age Classes ◽  
Population Age Structure ◽  
The Relationship

Spotted knapweed (Centaurea maculosa Lam. # CENMA) communities were sampled to determine the relationship between age and the number of root rings, and the population age structure. Spotted knapweed taproots add one ring of secondary xylem annually. In 1984, populations were expanding with high densities of individuals in the early age classes, followed by a steady decline in the older classes. In 1985, the majority of the individuals in knapweed populations were in the older age classes. This change in the population age structure was attributed to high mortality among the young age classes due to a drought in 1985. The maximum age class at the sites ranged from 5 to 9 yr. The percentage of plants with floral stalks increased with age to a peak of 75% in the fifth year in 1984 and in the seventh year in 1985.

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