bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Biology and Behaviour of Ptinus Tectus Boie. (Coleoptera, Ptinidae), A Pest of Stored Products
Authors: Gunn D. L. , Walshe B. M. 
Published: April 2021

ABSTRACT
In a long temperature gradient apparatus, Ptinus tectus aggregates around two distinct temperatures, 4 and 24° C. In a circular temperature alternative chamber there is no marked avoidance of low temperatures if the gradient is steep, but characteristic avoiding reactions occur if the gradient is not very steep. When the stationary animals are subjected to rising or falling temperatures in the long gradient, there is a well-marked evacuation temperature at 30–33° C., but none at lower temperatures. A temperature preference around 24° C. is correlated with favourable temperature for growth and other activities. The aggregation around 4° C. is the result of a failure of co-ordinated behaviour in a particular kind of gradient, and P. tectus is practically immobilized by cold in that temperature region.
Second Report on a Test of McDougall’s Lamarckian Experiment on the Training of Rats
Authors: Agar W. E. , Drummond F. H. , Tiegs O. W. 
Published: April 2021

ABSTRACT
The late Prof. McDougall’s four ‘Reports on a Lamarckian Experiment’ are likely to become a classic of experimental biology, as being the most sustained attempt up to the present to demonstrate the reality of Lamarckian inheritance in a particular instance. Although, as will appear from this account of our own experiment, we do not believe that it will take its’ place in the history of biology as a successful attempt, we take this opportunity of acknowledging our appreciation of his nearly twenty years’ devotion to this very laborious and exacting experiment.
The Relation of Animal Size to Oxygen Consumption in Some Fresh-Water Turbellarian Worms
Authors: Whitney R. J. 
Published: April 2021

ABSTRACT
A size factor is demonstrated for the oxygen consumption at 14·5°C. of four species of fresh-water Turbellaria obtained from different habitats. For three of the species studied (Polycelis cornuta, Crenobia alpina and Planaria polychroa) small animals were found to have a higher oxygen consumption per unit weight than large ones. In the case of Polycelis nigra small animals were shown to have a lower oxygen consumption per unit weight than large ones. The adherence of the size factor to the surface law of Rubner is discussed. Only Crenobia alpina satisfies the theoretical requirements of the law, and in this species it is shown that the size factor is practically unchanged when the oxygen consumptions are determined at 7·0°C. instead of 14·5°C.
Studies On the Fate of Carbohydrates in the Rumen of the Sheep
Authors: Phillipson A. T. , Mcanally R. A. 
Published: April 2021

ABSTRACT
It was shown in a previous paper (Phillipson, 1942) that the rate of fermentation in the rumen of the sheep appeared to be correlated to the type of carbohydrate present, that a feed of mangolds which contain a high content of soluble sugar, mostly cane sugar, fermented rapidly, that a feed of hay which contains mostly cellulose fermented slowly, whilst starchy foods fermented less rapidly.
The Blood Pressure of the Chick Embryo During Development
Authors: Hughes A. F. W. 
Published: April 2021

ABSTRACT
An apparatus is described for the measurement of the pressure in the chorioallantoic artery of the chick embryo. Data are given of such measurements ranging in time from the second to the nineteenth days of incubation. Some measurements are also given of the arterial pressure of the chick within the first five days after incubation.
The Effect of Crowding Upon the Oviposition of Grain-Infesting Insects
Authors: Crombie A. C. 
Published: April 2021

ABSTRACT
The crowding of adults invariably had a depressing effect upon the rate of oviposition in the insects studied here, while egg-fertility was not affected. In unconditioned media, at densities possible in actual populations, the reduction of fecundity was, it appears, entirely a result of competition for the oviposition sites usually for two purposes, viz. oviposition and feeding. That is to say, at such densities the effect of crowding upon oviposition was of a behaviouristic nature. When two species were living in the same environment their mutual effect upon each other’s fecundity was more or less dependent upon the degree of identity of the niches for which they were competing. The reduction of fecundity of Rhizopertha by homotypically and heterotypically conditioned media was at first roughly proportional to the degree of conditioning, but after a time the effect of all media was the same. Homo- and hetero-typical conditioning were not radically different in effect. It is believed that conditioned medium operates upon fecundity through ‘poisoning’, and that the effect is upon oviposition rather than, as that of starvation, upon egg-production. When returned to an optimum environment the insects recovered from all the experimental conditions mentioned here : immediately from conditions of overcrowding, more slowly from conditioned media, and more slowly still from complete starvation.
Nearfield detection of dipole sources by the goldfish (Carassius auratus) and the mottled sculpin (Cottus bairdi)
Authors: Coombs Sheryl 
Published: April 2021

ABSTRACT
Surprisingly few behavioral data exist on dipole source detection by fish, despite the fact that dipole sources more closely approximate biologically relevant signals than do more nearly monopole sources such as loudspeakers, the stimulus used in nearly all fish auditory studies. In this study, dipole source detection is investigated for two fish species that differ in both their auditory and lateral line systems, the two systems capable of detecting dipole sources. Conditioned suppression of respiration in the goldfish and an unconditioned orienting response in the mottled sculpin were used to measure detection of a 6 mm diameter, sinusoidally vibrating sphere as a function of vibration frequency and source distance.
Sound pressure thresholds for the goldfish were nearly independent of distance (15–60 mm) at 800 Hz, but increased with distance at 50 Hz, as they did for the mottled sculpin. The slopes of 50 Hz source level–distance functions, however, differed between the two species. Slopes for the goldfish were independent of distance, remaining at around 8 dB per distance doubling, which is near the 6 dB per distance doubling measured for sound pressure attenuation away from the source, but less than the 18 dB per distance doubling for incompressible flow, measured with an anemometer. Those for the mottled sculpin increased with increasing distance, approaching 18 dB per distance doubling. The nonlinear increase in source level necessary to reach threshold detection was quite similar to the nonlinear decrease in incompressible flow levels measured with the anemometer. Nonlinear increases with distance for 50 Hz sources near the trunk of the mottled sculpin were also similar to those near the head of the fish, where changes in source frequency had little effect on source level–distance functions.
These results indicate that sound pressure detection by the ear is important for dipole detection by the goldfish, but that incompressible flow detection by the lateral line is more important for the mottled sculpin. They also indicate that fish such as the goldfish, with a pressure-sensitive swimbladder, are capable of detecting dipole sources at greater distances than are fish without such structures.
Mobilization of shell calcium by the chick chorioallantoic membrane in vitro
Authors: Packard Mary J. 
Published: April 2021

ABSTRACT
Two explants of shell were removed from each of several fertile eggs of domestic fowl at different times during incubation. The chorioallantoic membrane (CAM) was removed from one of the explants (SHELL ONLY) and was left in situ on the other (SHELL+CAM). Explants were cultured for 24, 48 or 96 h at 37 °C and 5 % CO2 in air in individual Petri dishes containing Dulbecco’s modified Eagle’s medium, bovine serum albumin, penicillin and streptomycin. Both SHELL+CAM and SHELL ONLY explants released calcium into the culture medium, but the former released considerably more calcium than the latter. More calcium was released by SHELL+CAM explants taken from older eggs than from younger ones, but the age of the donor eggs did not affect release of calcium by SHELL ONLY explants. In addition, release of calcium by SHELL+CAM explants exceeded that shown by SHELL ONLY explants for multiple 24 h intervals. However, the capacity for sustained release of calcium by SHELL+CAM explants declined with age and maturity of the CAM. Manipulations that lead to the death of the CAM abolish the capacity for SHELL+CAM explants to release more calcium than SHELL ONLY explants. Differential release of calcium by SHELL+CAM explants was not attributable to calcium present in the CAM at the onset of culture or to non-specific degradation of the shell by intracellular constituents released as a result of the death of the CAM. Taken in concert, these results indicate that the CAM mobilizes calcium from the eggshell during in vitro culture.
Diving energetics in lesser scaup (Aythyta affinis, Eyton)
Authors: Stephenson Richard 
Published: April 2021

ABSTRACT
Mechanical and aerobic energy costs of diving were measured simultaneously by closed-circuit respirometry in six lesser scaup Aythya affinis Eyton (body mass=591±30 g) during bouts of voluntary feeding dives. Durations of dives (td=13.5±1.4 s) and surface intervals (ti=16.3±2.2 s) were within the normal range for ducks diving to 1.5 m depth. Mechanical power output (3.69±0.24 W kg−1) and aerobic power input (29.32±2.47 W kg−1) were both higher than previous estimates. Buoyancy was found to be the dominant factor determining dive costs, contributing 62 % of the mechanical cost of descent and 87 % of the cost of staying at the bottom while feeding. Drag forces, including the contribution from the forward-moving hindlimbs during the recovery stroke of the leg-beat cycle, contributed 27 % and 13 % of the mechanical costs of descent and feeding, respectively. Inertial forces created by net acceleration during descent contributed approximately 11 % during descent but not at all during the feeding phase. Buoyant force at the start of voluntary dives (6.2±0.35 N kg−1) was significantly greater than that measured in restrained ducks (4.9±0.2 N kg−1). Loss of air from the plumage layer and compression due to hydrostatic pressure decreased buoyancy by 32 %. Mechanical work and power output were 1.9 and 2.4 times greater during descent than during the feeding phase. Therefore, energetic costs are strongly affected by dive-phase durations. Estimates by unsteady and steady biomechanical models differ significantly during descent but not during the feeding phase.
Gas Exchange of Captive Freely Diving Grey Seals (Halichoerus Grypus)
Authors: Reed J. Z. , Chambers C. , Fedak M. A. , Butler P. J. 
Published: April 2021

ABSTRACT
When at sea, phocids dive for long periods and spend a high percentage of their time submerged. This behaviour requires some combination of an increased oxygen storage capacity, rapid oxygen loading at the surface and reduced oxygen utilisation when submerged. To assess these adaptations, breath-by-breath ventilation was studied in four adult grey seals (two male, two female, 160–250 kg), freely diving in a large outdoor tank where surface access was restricted to one breathing hole. The dive patterns obtained were similar to those recorded from freely diving wild grey seals. Respiratory frequency during the surface periods was 40% higher than that estimated from allometric relationships (19.4±0.7 breaths min−1), and tidal volume (6.3±1.2 l) was approximately five times higher than that estimated from allometric relationships. These adaptations produce a high minute volume and enable gas exchange to occur at the surface.
Mean oxygen consumption rate (, measured for a dive+surface cycle) decreased with increasing dive duration. The aerobic dive limit was estimated as 9.6 min for a 150 kg grey seal (using the overall average of 5.2 ml O2 min−1 kg−1), which is consistent with results from freely diving wild grey seals (only 6% of dives exceeded 10 min). End-tidal oxygen values varied during a surface period, following a U-shaped curve, which suggests that there is limited oxygen uptake from the lung and/or blood oxygen stores during dives. This result was unexpected and indicates that these seals are utilising substantial physiological responses to conserve oxygen, even during shallow voluntary diving.
Effects of Confinement/Crowding on Ureogenesis in the Gulf Toadfish Opsanus Beta
Authors: Walsh Patrick J. , Tucker Bonnie C. , Hopkins Todd E. 
Published: April 2021

ABSTRACT
In order to elucidate the cues for, and the biochemical mechanisms of, the transition to ureogenesis in the gulf toadfish Opsanus beta, experiments on the effects of confinement/crowding were carried out. Confinement of toadfish to small volumes of water initiated a switch to nearly complete reliance on ureogenesis for nitrogen excretion within 24–48 h. Further experiments suggested that this switch was probably due to the physical confinement per se, rather than to a measurable build-up of ammonia in the water. However, the possibility of the response being triggered by a very low concentration of a pheromone-like substance was not excluded by our experimental design. The activities of several enzymes of ureogenesis, ornithine–citrulline transcarbamoylase, aspartate amino transferase and glutamine synthetase, increased in the liver of toadfish during confinement. Notably, glutamine synthetase activity increased almost fourfold within 24 h, and this increase preceded increases in urea excretion. A number of plasma and liver amino acid concentrations changed during confinement: there were declines in plasma asparagine, glutamate and glycine levels and an increase in plasma valine, as well as a decline in liver alanine and an increase in liver arginine concentrations. Liver glutamine was not detectable. When the amino acid data are taken together with the enzyme activity changes, it appears that the switch to ureogenesis occurs primarily upstream of the ornithine–urea cycle, at the level of supply of nitrogen to the pathway. The results are discussed in the context of the habitat of toadfish.
Gravity and Light Influence the Countershading Reflexes of the Cuttlefish Sepia Officinalis
Authors: Ferguson Graham P. , Messenger John B. , Budelmann Bernd U. 
Published: April 2021

ABSTRACT
Rotation (roll or pitch) of a cuttlefish away from its normal orientation produces countershading reflexes (CSRs) that consist of chromatophore expansion on the ventral body surface. When rotation is in the roll plane, the CSR has two components on each side of the body. The first (component A) consists of a unilateral expansion of chromatophores on the uppermost latero-ventral edge of the mantle, the underside of the upper fin and the uppermost side of the head; it occurs when the angle of rotation is less than 90°. Further rotation (from approximately 90° to approximately 180°) adds the second component (component B): a unilateral expansion of the chromatophores on the upper half of the ventral surface of the mantle, funnel, head and arms. When rotation is in the pitch plane, chromatophores expand on the posterior part of the ventral mantle and fins when the head is down; when the head is up, chromatophores expand on the ventral surface of the arms, head and funnel and on the anterior part of the ventral mantle and fins. The pitch CSR is always bilateral.
Destruction of the gravity or the angular acceleration receptor systems of the statocysts demonstrates that it is the gravity receptor systems that drive the CSRs. Unilateral destruction of the gravity receptor systems shows that the pitch CSR is driven bilaterally, whereas the roll CSR is driven unilaterally. Components A and B of the roll CSR are driven by input from the ipsilateral statocyst, but component A is additionally driven by light.
Brain lesions provide evidence that the pathways for the CSRs run through the lateral basal lobes in the supraoesophageal part of the brain.
A Quantitative, Three-Dimensional Method for Analyzing Rotational Movement From Single-View Movies
Authors: Van Den Berg Coen 
Published: April 2021

ABSTRACT
The study of animal movement is an important aspect of functional morphological research. The three-dimensional movements of (parts of) animals are usually recorded on two-dimensional film frames. For a quantitative analysis, the real movements should be reconstructed from their projections. If movements occur in one plane, their projection is distorted only if this plane is not parallel to the film plane. Provided that the parallel orientation of the movement with respect to the film plane is checked accurately, a two-dimensional method of analysis (ignoring projection errors) can be justified for quantitative analysis of planar movements.
The Scaling of Song Frequency in Cicadas
Authors: Bennet-Clark H. C. , Young D. 
Published: April 2021

ABSTRACT
In male cicadas, sound is generated by a pair of tymbals on the abdomen (Pringle, 1954). The tymbals buckle inwards causing pressure changes in the abdominal cavity, from which sound is radiated through the tympana (Young, 1990). A recent model of sound production in cicadas suggests that the abdominal cavity and tympana act as the components of a Helmholtz resonator that is excited by the drive from the tymbals (Bennet-Clark and Young, 1992). A Helmholtz resonator consists of a cavity open to the outside via a hole which has a real or notional neck, and the resonant frequency f0 is given by the general equation: where c is the speed of sound in the fluid, taken as 340 m s−1 for air, A is the area of the neck, L is the length of the neck and V is the volume of the cavity. Where the resonator has two holes, these terms should be somewhat modified: A is the combined area of the two holes, L is 16/3πr (≈1.7r) for a simple hole in a thin-walled vessel and r is the radius of one hole (Seto, 1971). These modifications to equation 1, which include corrections for the acoustic end-effect at either side of a simple hole in the wall of a vessel, are applicable to a model of the male cicada, in which there are two tympana close to the ventral surface of the abdomen.
The Ontogeny of Shivering Thermogenesis in the Red-Winged Blackbird (Agelaius Phoeniceus)
Authors: Olson John M. 
Published: April 2021

ABSTRACT
The ontogeny of shivering thermogenesis was investigated in the altricial red-winged blackbird (Agelaius phoeniceus). Two indices of heat production – the rate of oxygen consumption of the bird and the electromyographic (EMG) activity of the pectoralis (PECT) and gastrocnemius (GAST) muscles – were measured simultaneously in adult and nestling red-winged blackbirds as they were subjected first to thermoneutral temperatures and subsequently to progressively colder ambient temperatures (Ta). The ontogenetic changes in both indices indicated that the capability for thermogenesis in nestling red-winged blackbirds improved markedly with age. The metabolic rates of 3-day-old nestlings decreased during exposure to gradually falling ambient temperatures; at best, these nestlings were only able to maintain mass-specific at levels similar to or slightly above the resting metabolic rate at thermoneutral temperatures (RMR) for a short time before metabolic rates decreased with further cooling. Shivering was detected only in the PECT muscles and was of a relatively low intensity (maximum of sevenfold increase in intensity over basal levels). The 5-day-old nestlings increased mass-specific modestly (approximately 1.4-fold) above RMR and attained slightly higher maximal factorial increases in the EMG activity of the PECT (maximum of 18-fold basal levels) when exposed to the same experimental conditions. Shivering was also detected in the GAST muscles of these birds. The most striking improvements in both measures observed during the nestling period occurred between day 5 and day 8. Eight-day-old nestlings increased metabolic rates by approximately 2-to 2.5-fold over basal levels and sustained these elevated rates for longer before becoming hypothermic. Both the PECT and GAST muscles contributed significantly to shivering thermogenesis, and these older nestlings attained much higher factorial increases in the intensity of shivering (up to 72-fold) during exposure to cold temperatures. In addition, both the range and magnitude of the dominant frequencies of muscle activity in the PECT increased during postnatal development.
The PECT muscles were a principal site of shivering thermogenesis in all nestling and adult red-winged blackbirds studied here. Shivering in these muscles was a ‘first line defense’ against cold; the threshold temperature for shivering in the PECT muscles coincided with the lower critical temperature for oxygen consumption (TLC), and the subsequent increases in EMG activity in this muscle with further cooling correlated well with the corresponding increases in mass-specific .
Power Output of Scallop Adductor Muscle During Contractions Replicating The In Vivo Mechanical Cycle
Authors: Marsh Richard L. , Olson John M. 
Published: April 2021

ABSTRACT
Because measurements on isolated skeletal muscles are often made with limited knowledge of in vivo kinematics, predictions of mechanical performance during natural movements are subject to considerable uncertainties. We used information on the in vivo length cycle and phase of activation of the scallop adductor during swimming at 10°C to design an in vitro contractile regime that replicated the natural cycle. Replicating the in vivo length cycle and stimulation regime resulted in power output during cyclic contractions that matched in vivo performance both qualitatively and quantitatively. When sinusoidal length changes were used instead of the natural length trajectory, the adductor muscle produced a similar average power output (approximately 30 W kg−1 at 1.9 Hz), but the distribution of power throughout the cycles was quite different. We examined the instantaneous force–velocity properties during cyclic contractions and found that the muscle operated on or near its isotonic force–velocity curve for only 30–40% of the time required for shortening. During sinusoidal length cycles, the force–velocity trajectory was quite different. We conclude that during cyclic contractions the isotonic force–velocity curve of skeletal muscle sets an approximate boundary to the force–velocity trajectory, but the shape of this trajectory, and thus the distribution of power output, depends on the pattern of length change.