bluuebunny/crossref_metadata_2025_split huggingface dataset:
The transmission of 125I labelled globulins to the circulation in young rats
Authors: Morris B. , Begley D. 
Published: August 2009

The total and bound concentration quotients (C.Q.s) developed after intraperitoneal administration of globulin preparations are considerably greater than those developed after oral administration in young rats aged 15, 20, 23 and 27 days.Over this age range the total C.Q.s developed after intraperitoneal administration decline more sharply than those developed after oral administration, suggesting that the mechanism of protein absorption from the peritoneum becomes comparatively less efficient during this period. At 27 days of age, contrasting with earlier stages, considerable degradation of the intraperitoneally administered dose occurs.The duodenum of unweaned 28 day old rats is capable of transmitting to the circulation large quantities of labelled globulin with apparently little degradation or selection. This ability is virtually lost by 33 days. The jejunum of unweaned 28 day old rats transmits only very small quantities of labelled globulin to the circulation, and there is considerable degradation of the injected dose.These several factors are discussed in the general context of the postnatal transfer of passive immunity in this species.
The testicular cycle and androgen biosynthesis in the tree sparrow Passer montanus saturatus
Authors: Chan K. M. B. , Lofts B. 
Published: August 2009

The annual testicular cycle of the tree sparrow (Passer montanus saturatus) has been studied by histochemical and biochemical techniques.The spermatogenetic cycle has two clearly defined peaks of activity. Throughout the winter the gonads are sexually regressed, but a recrudescence of spermatogenetic activity begins in the spring and the gonads rapidly develop into full breeding condition by April. In late April and early May a rapid testicular regression takes place as spermatogenetic activity terminates. Then, in July, a second seasonal spermatogenetic wave begins and gonads once again develop into a breeding condition. By August the testes have become fully regressed into their sexually quiescent post‐nuptial phase and remain this way until the following spring. The seasonal rehabilitation of the interstitial tissue, which is a characteristic part of many avian cycles, does not occur until this latter regressive phase.The seasonal fluctuations in the in vitro production of testosterone from A5‐pregnenolone‐16T shows the same annual bimodal pattern as the spermatogenetic cycle, being high at times when the seminiferous tubules are spermatogenetically active, and low during times of sexual quiescence. There is a close correlation between the level of testicular androgen synthesis and the seasonal fluctuations in the interstitial cell lipid cycle. Thus, testosterone synthesis builds up in the spring at a time when small sudanophilic lipid droplets are present in the interstitial Leydig cells, and reaches a peak at a time when this material is becoming rapidly depleted from the cell cytoplasm. During the first period of testicular regression, the Leydig cells become markedly sudanophilic, possibly as a result of the accumulation of precursor material at a time of low testosterone synthesis, then again become depleted of this material as secretory activity builds up once again.The possible interrelationship between the histochemical and biochemical cycles, and also the spermatogenetic cycle and the daily photoperiods, are discussed.
The effects of oestrous condition and familiarity on the sexual behaviour of polecats (Mustela putorius and M. fur × M. putorius hybrids)
Authors: Poole Trevor B. 
Published: August 2009

The effects of two factors on the sexual behaviour of polecats (Mustela furo and M. putorius×M. furo hybrids) were investigated, in an indoor arena of 16 m2, firstly the oestrous condition of the female and secondly the familiarity of the two individuals.The initial approaches of a male polecat are similar irrespective of the oestrous condition of the female but his subsequent behaviour is dependent upon the female's response. Whereas males copulated with oestrous females they showed a wider repertoire of social acts and a greater number of changes of behaviour towards females which were not in oestrous. Unreceptive females elicited both sexual and aggressive behaviour from males.Unfamiliar females provide a more powerful eliciting stimulus for the male's copulatory behaviour than do familiar females.
The blood circulatory function of the dorsal aorta ligament in Rainbow trout (Salmo gairdneri)
Authors: Priede Imants G. 
Published: August 2009

An elastic longitudinal ligament stretched under considerable tension lies within the dorsal aorta of Rainbow trout.Experiments with mechanically simulated swimming movements in an artificial model demonstrate that such a ligament can act as a pump mechanism. The output of the pump increases with tail beat frequency up to a certain point where the mechanism tends to break down. Investigations on the trout dorsal aorta show that pump breakdown probably takes place at relatively low output pressures.Fundamental blood flow considerations indicate that a fully effective dorsal aorta pump over the full range of swimming speeds is undesirable. It is concluded that the dorsal aorta ligament can act as a pump which automatically increases circulation during swimming particularly to the body musculature. The output pressure is small but may be of significance in causing reflex increase in cardiac output.
An investigation of playful behaviour in Rattus norvegicus and Mus musculus (Mammalia)
Authors: Poole Trevor B. , Fish Jane 
Published: August 2009

The playful behaviour of laboratory rats (Rattus norvegicus) was investigated in litters of five individuals with the mother present; parallel observations were made on mice (Mus musculus). Seven mixed litters containing four young rats and a young mouse fostered at birth were also observed.Solitary play was recorded in both species and took a similar form but social play was only observed in rats. In rats, solitary play frequently preceeded social play.The behavioural elements involved in the social play of Rattus norvegicus were described, and the majority of these were the playful equivalent of adult agonistic behaviour elements. These social play elements were found to be organized into definite sequences which differed from those of adult aggression. Each behavioural element was found to act as a social releaser.Young mice did not respond playfully to social play from a rat litter mate; mice were less attractive to rats as playmates in comparison with fellow rats.
Observations on the use of grottos by Mediterranean Monk seals (Monachus monachus)
Authors: Bareham J. R. , Furreddu A. 
Published: August 2009

A group of six Monk seals (Monachus monachus) was discovered to lie up inside a grotto on the shores of a lake reached via an underwater passage. Nearly 1200 hours of observation on the movement of the seals showed that the greatest use of the grotto was made during the winter months and when the wind was towards the grotto entrance. Entry and exit times were not significantly affected by sea state, dark or light, nor were they significantly correlated with sunrise and sunset times or sea and air temperature. These variables did not significantly affect the length of stay in the grotto. Entry occurred most frequently in the early morning and exist at night.Discussion is given of the possible reasons why grottos are used by Monk seals. This appears to be a recent adaptation which may be related to the effects of human disturbance.
Studies on the chemical ecology of Biomphalaria glabrata: The effects of chemical conditioning by the snails kept at various densities on their growth and metabolism
Authors: Thomas J. D. , Goldsworthy G. J. , Benjamin M. 
Published: August 2009

It has been shown that heterotypically conditioned media (Het. C.M.) produced by lettuce fed snails maintained at various densities can influence the allometric growth and the rates of specific growth, ingestion, egestion, assimilation and heart beat of isolated assay snails. The growth rate of the assay snails was enhanced by increasing the density of snails producing the Het. C.M. to an optimum threshold of one snail per 100 ml. Further increases in density were followed by a decline in their growth rate. The higher growth achieved by the assay snails in the optimum treatment can be attributed to the fact that their specific growth rates over the first three weeks of the experiment were higher than those of snails in other treatments.Ingestion and assimilation correlated well with specific growth rates. Percentage assimilation values are high, ranging from 78.4 to 89.6%. The onset of reproductive activity is followed by a dramatic decline from approximately 26 % to 5 % in the gross efficiency of utilization of food for somatic growth.Snails not receiving Het. C.M. from the outer tanks have a relatively higher ratio of specific growth rate in weight to length than was the case with snails in the other treatments. The heart beat rates of snails in the Het. C.M. produced by snails at densities of 80 to 160 snails per 41 are significantly lower than those of snails at other densities. The possible causation and adaptive significance of these effects are discussed.
The feral goats of Kielderhead Moor
Authors: MCDOUGALL PETER 
Published: August 2009

Herds of feral goats are present along the high ground of the Scottish Borders at the College, Hindhope, Kielderhead Moor (the study area), Bewcastle Fell and Roan Fell.In the study area the nannies remained solitary, or in the company of their yearlings on the steep ground below the high moor throughout the winter. After the birth of their kids in March two female herds were formed each with a herd billy which came from the two male herds which were present through the winter on the high moor. The male herds left the study area in the spring and their ranges are not known. The two female herds maintained separate ranges on the high moor until the end of August when they combined into one large herd and were joined by a strange herd of billies which had not previously been seen.After the first three or four days of its life the kid is left in a hiding place for most of the day whilst its mother ranges widely grazing with the herd. The kids join the herd when they are about six weeks old.The Kielderhead Moor goats had a recruitment rate of 0–29/nanny/year and the females have a further expectation of life of 3–7 years. Figures for the billies are unreliable as disappearances of males from the moor are more likely to be the result of emigration than of deaths. While the herds of nannies have fairly restricted home ranges there is some evidence to suggest that many of the billies wander freely along the Borders.In the early part of the summer the sheep and goats are eating very similar proportions of the plants present on the moor. Later on in the season there is a divergence with the sheep eating less Calluna while the goats eat less Eriophorum, but as the Trichophorum becomes available both animals include this in their diet.
The reproductive cycle, condition and feeding in Barbus liberiensis, a tropical stream‐dwelling cyprinid
Authors: PAYNE A. I. 
Published: August 2009

This investigation examines the biology of Barbus liberiensis, a small cyprinid living in the forest streams of Sierra Leone and Liberia, in relation to seasonal changes in the environment. The population studied showed a single discrete breeding season coinciding with the early part of the rains. Maturing fish previously marked moved upstream at this time. The pattern of gonad development is analysed and the relationship of fecundity to body size is defined numerically. The total and somatic (i.e. excluding gonad weights) condition of the fishes, relative to the length/weight data in September‐November when the gonads are resting, reach a peak at spawning time for both mature males and females and for immature fish. The pattern of condition during a year differs in the two sexes. B. liberiensis consumes a wide variety of foods but relies largely on insects and higher plant fragments. Debris from the forest canopy is an important source of nutriment. The fish feed, during the daytime and possibly at night, throughout the year. Experiments to determine the rate at which food passes through the gut are described and show that food passage is rapid.The seasonal cycles in condition and reproduction are discussed in relation to cycles in some other tropical and temperate riverine fishes.
Locomotion, pedal retraction and extension, and the hydraulic systems of Bullia (Gastropoda: Nassaridae)
Authors: Trueman E. R. , Brown A. C. 
Published: August 2009

Surface locomotion and burrowing by Bullia digitalis have been analysed by use of ciné film and electronic recording. Both movements are shown to be carried out by a series of steps in which the propodium is first extended whilst the snail is anchored by the posterior of the foot (penetration anchor) and, when buried, also by the shell; secondly the shell is drawn forwards and downwards towards the anchored propodium (terminal anchor). The extremely flattened foot of this snail contains a greatly enlarged pedal sinus containing blood and functions as a hydraulic organ. This contrasts with the foot of most gastropods, e.g. Patella, which crawl over hard surfaces and have no large fluid filled pedal cavity.During each step, or digging cycle, there are two pressure pulses, one effecting propodial extension, the second occurring as the shell is drawn forwards. The pedal haemocoel is isolated from the remainder of the circulation for at least part of the locomotory cycle so enabling the foot to function as a fluid‐muscle system at constant volume. Bullia exhibits convergence with burrowing bivalve molluscs having a similar pattern of alternating anchorages in sand and in both water is ejected from the mantle cavity to liquefy the sand in front of the shell.The energy cost of burrowing by B. digitalis is estimated to be 6.6 times 10‐6 J/mg dry tissue weight, a figure comparable to that of the clam Donax provided that burial occurs at a similar rate. By contrast the energy requirement for Bullia to move over the surface of sand is about one tenth of that for burial.Pedal extension involves both blood flow, so that the foot may function as a hydraulic system, and direct muscular antagonism between the fibres of a three dimensional muscle network in the opercular muscle. When the snail is extended the shell contains some sea‐water which plays a dynamic role in pedal expansion and retraction independently of the pedal blood sinus. The possible role of this cavity in other prosobranchs is discussed.
Body size and composition of Crabeater seals (Lobodon carcinophagus), with observations on tissue and organ size in Ross seals (Ommatophoca rossi)
Authors: Bryden M. M. , Erickson A. W. 
Published: August 2009

Linear body measurements and body weights of 17 Crabeater seals and four Ross seals were recorded, and the relationships of weight to linear dimensions were calculated. There were no significant differences between sexes of these relationships in Crabeater seals. All Ross seals were males.The major body components (blood, fat, skin, muscle, bone, connective tissue and viscera) of seven Crabeater seals were weighed after dissection.Blood, fat and skin of two Ross seals were weighed. Weights of 22 visceral organs of the same animals, and linear bone dimensions of eight Crabeater seals and skull measurements of five Ross seals were recorded.There was no significant difference between sexes or ages in body composition of Crabeater seals. Relatively, Crabeater and Ross seals had less blood (9–10% body weight) than Elephant seals, and less fat (21–22% body weight) than most other marine mammals. The low body fat content may have been attributable to season and physiological status of the animals when dissected. The percentages of body weight represented by the other major components of Crabeater seals were: skin 8%, muscle 44%, bone 10%, connective tissue 0.7% and total viscera 8%. These figures, and the relative sizes of individual organs, were discussed in relation to their possible function in Crabeater and Ross seals.
The breeding of the Sooty tern Sterna fuscata in the Seychelles and the effects of experimental removal of its eggs
Authors: Feare Christopher J. 
Published: August 2009

In the Seychelles the eggs of the Sooty tern Sterna fuscata are collected for human consumption. A reduction in the number of Sooty terns breeding in exploited colonies has been attributed to over‐exploitation of the eggs. However, the population decline has been over‐estimated and factors other than exploitation have led to a reduction in the land area available to breeding colonies.In the study colony, on Bird Island, egg laying was highly synchronous, and birds which laid at peak laying time had a higher reproductive success than those that laid early or late. The higher success of these birds was due to their being at the same stage of the reproductive cycle as their neighbours: this reduced losses of eggs to predators and losses of chicks due to pecking by adults and other chicks. Birds which laid late, which included young birds and birds which had lost their first egg and laid a replacement, were therefore penalized.The ability to lay a replacement egg after loss of the first, was found experimentally to be much greater than previous estimates had suggested, and some individuals were induced to lay a third egg. Both the ability to relay and the success of replacement eggs declined seasonally. The laying of a replacement egg did not seem to place extra strain on the parents, and the lower weights of most replacements compared with first eggs was due to seasonal factors rather than to the inability of adults to produce a large second egg.The food brought by the parents to the chicks consisted mainly of fish and squid, but frequent and abrupt changes in the species composition of the food suggested that food supplies were unpredictable. In 1973 chick growth was interrupted by two periods of food shortage, and although late hatched chicks experienced this food shortage early in their lives, starvation did not appear to be a major source of mortality.The regulation currently in force in the Seychelles imposing a close season for egg collecting protects only late‐laid eggs, and since these have a very low success rate and can contribute little to future generations, there is no biological foundation for continuing this restriction. Adult mortality and age at first breeding are not known for Seychelles Sooty tern populations, and exploitation should be restricted to 10–20% of the birds that lay during the main laying period.
Light intensity as a factor in the regulation of the density of symbiotic zooxanthellae in Aiptasia tagetes (Coelenterata, Anthozoa)
Authors: Steele R. Dunbar 
Published: August 2009

Experiments designed to investigate the effect of different levels of illumination on the density of symbiotic zooxanthellae in the anemone Aiptasia tagetes (Duch. & Mich.) are described.The anemones are found to regulate the densities of their zooxanthella populations to fixed levels which are dependent upon ambient light intensity.Regulation is continuous and results from the interaction of increase in algal numbers, growth of host tissues, population of new host tissues by symbionts and extrusion of zooxanthellae by the host.The nature of the process by which zooxanthellae are selected for extrusion is discussed and a scheme is outlined indicating the pathways through which the level of the algal population in Aiptasia, and other coelenterates, is believed to be controlled.
The biology, ecology and functional aspects of the organs of feeding and digestion of the S.E. Asian mangrove bivalve, Enigmonia aenigmatica (Mollusca: Anomiacea)
Authors: Morton Brian 
Published: August 2009

Enigmonia aenigmatica (Holten 1803) is an anomiid bivalved mollusc highly adapted for life attached to the trunks, projecting prop roots and leaves of mangrove trees. It is a characteristic member of the S.E. Asian mangrove community.It exists in four growth forms, or morphs determined by the nature of the surface on which settlement takes place. It is also orientated and positioned on the tree trunks of Avicennia and the prop roots of Rhizophora, in relation to the long axis of the tree and the direction of the current. Further aspects of the biology and ecology of Enigmonia are discussed. Enigmonia is monomyarian and lies on its right shell valve. This has resulted in an asymmetry which is of especial significance with regard to an understanding of the functional morphology of the organs of feeding and digestion in particular. The eccentricities seen in Enigmonia have been compared with the adaptations found in other anomiids in particular and other bivalves in general.The feeding and digestive cycle of Enigmonia has been described and found to be correlated with the rhythm of the tide; it is essentially similar to that described for some other littoral bivalves.The adaptations and specializations of Enigmonia are discussed in relation to its life in the mangal.
The adaptive and classificatory significance of certain quantitative features of the forelimb in primates
Authors: Ashton E. H. , Flinn R. M. , Oxnard C. E. , Spence T. F. 
Published: August 2009

Quantitative osteological features of the primate brachium and antebrachium can be defined in relation to functionally significant contrasts in the principal muscle blocks. Such features, as shown by univariate and multivariate statistical study of a total of 525 sets of arm bones from 39 primate genera, demonstrate a broad correlation with the extent to which the forelimb is subject to tensile forces during locomotion. Man, in different features, resembles contrasting groups of non‐human Primates; in sum total of such characteristics, he is unique.Other dimensional characters, defining more general features of the arm bones differentiate individually, but more especially in multivariate combination, between major taxonomic groups within both Prosimii and Anthropoidea.In combination, the two groups of dimensions give a separation that is primarily taxonomic but which has a locomotor underlay.When, in sum total, the dimensional characters of the arm are combined with those of the shoulder (where, as established in earlier work, the separation produced is almost exclusively locomotor), the initial division is in accordance with locomotor function of the forelimb—and especially the extent to which the limb is subjected to tensile forces. But there is a strong taxonomic underlay.A method is thus provided for enquiry into both the taxonomic and functional significance of arm bones of fossil Primates.The work, in addition to endorsing the classical concept of Man's retention of primitive mobility in the distal segments of his forelimb, also re‐emphasizes his uniqueness through arm mobility being associated with shoulder action principally caudal and ventral to the joint.