bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Physiology and Energetics of Bat Flight
Authors: Thomas Steven P. , Suthers Roderick A. 
Published: April 2021

ABSTRACT
Bats are unique in being the only mammals capable of flight. The mobility, speed, and agility associated with this means of locomotion must have been an important factor in their successful radiation, which has made this diverse group the second largest order of mammals. Excluding man, and possibly rodents, bats have the widest distribution of any terrestrial mammals (Simpson, 1945; Walker, 1964; Anderson & Jones, 1967).
Despite a growing literature on the physiology of resting or hibernating bats, almost nothing is known regarding the physiology or energetics of bat flight. Mammalian flight is of particular physiological interest since recent studies of bird flight (e.g. Tucker, 1968b, 1969; Berger, Hart & Roy, 1970) show that it requires a metabolic rate well above the maximum of which similar size, terrestrial mammals are capable during exercise (Pasquis, Lacaisse & Dejours, 1970). Furthermore, birds possess a number of adaptations for flight which are not shared by mammals. In the following research we have measured the energetic cost of flight to a bat and attempted to determine what adaptations permit these mammals to maintain the high metabolic rates for which birds seem so uniquely specialized. Some of the data which we report here were summarized in a brief preliminary report (Thomas & Suthers, 1970).
The Activity of Lateral-Line Efferent Neurones in Stationary and Swimming Dogfish
Authors: Roberts B. L. , Russell I. J. 
Published: April 2021

ABSTRACT
The activity of efferent neurones innervating lateral-line organs on the body of dogfish was followed by recording from filaments of cranial nerve X in 41 decerebrate preparations. The efferent nerves were not spontaneously active. Tactile stimulation to the head and body, vestibular stimulation and noxious chemical stimulation were followed by activity of the efferent nerves. In contrast, natural stimulation of lateral-line organs (water jets) did not reflexly evoke discharges from the efferent fibres. Reflex efferent responses were still obtained to mechanical stimulation even after the lateral-line organs had been denervated. Electrical stimulation of cranial nerves innervating lateral-lines organs was followed by reflex activity of the efferent fibres. But similar stimuli applied to other cranial nerves were equally effective in exciting the efferent system. Vigorous movements of the fish, involving the white musculature, were preceded and accompanied by activity of the efferent fibres which persisted as long as the white muscle fibres were contracting. Rhythmical swimming movements were accompanied by a few impulses in the efferent fibres grouped in bursts at the same frequency as the swimming movements. It is concluded that the efferent neurones cannot contribute to a feedback regulatory system because they are not excited by natural stimulation of the lateral-line sense organs. The close correlation found between efferent activity and body movement suggests that the efferent system might operate in a protective manner to prevent the sense organs from being over-stimulated when the fish makes vigorous movements.
Lung-Air-Sac Anatomy and Respiratory Pressures in the Bird
Authors: Brackenbury John H. 
Published: April 2021

ABSTRACT
Regardless of its tidal volume an individual air sac shows a respiratory pressure-wave which is similar to that of every other sac. These is a process of pressure equilibration within the lung-air-sac system involving very short-lived streams of air between air sacs, whose significance becomes larger as pressure accelerations become bigger; and when a steady state has been achieved in any respiratory phase the pressure wave becomes normalized in all parts of the system. Small pressure differentials between sacs are part of the equilibrium distribution of pressure within the lung-air-sac system. They result from differences in the resistance path through the lung to each sac, and differences in their respective tidal volumes. Their wave-form closely resembles that of the parent pressure waves and has a maximum value of one-tenth their value. In general, the bronchial pathways to the posterior sacs have greater resistances to air flow than those to the anterior sacs. During vocalization pressures in the coelom and air sacs exceed normal respiratory pressures by about 40 times. Airway resistance vastly increases as the syringeal membranes begin to vibrate.
Tension at the Surface of the Dividing Sea-Urchin Egg
Authors: Yoneda Mitsuki , Dan Katsuma 
Published: April 2021

ABSTRACT
Several theories have been put forward to explain the mechanics of cleavage of animal cells. According to the expanding membrane theory of Mitchison and Swann (Mitchison, 1952; Mitchison & Swann, 1955; Swann & Mitchison, 1958), the cleaving furrow is passively pushed in as a result of ‘active’ expansion of poles; while the constricting ring theory (Marsland, 1950, 1956 a, b) anticipates that the furrow region has independent power to contract. A third alternative is ‘astral relaxation theory’ of Wolpert (1960), who advocates that cleavage is initiated by relaxation of the membrane in the polar region which allows the furrow to contract.
A Note on the Paling Centre of the Minnow (Phoxinus Phoxinus L.)*
Authors: Gentle Michael J. 
Published: April 2021

ABSTRACT
The degeneration of the tectal efferent fibres was studied using the paraffin Nauta technique following lesion to the optic tectum in Phoxinus phoxinus L. A degenerating fibre bundle of the tractus tecto-bulbaris ventralis rectus was found to end in a group of neurones in the anterior medulla.
The Control of Changes in Peripheral Sensilla Associated with Feeding in Locusta Migratoria (L.)
Authors: Bernays E. A. , Chapman R. F. 
Published: April 2021

ABSTRACT
The electrical resistance across the tips of the maxillary palps is not affected by stimulation of the palps, but increases to the normal level found after feeding as a result of distension of the foregut with agar or injection of corpus cardiacum homogenates into the haemolymph. No increase in resistance occurs if the posterior pharyngeal nerves or the frontal connectives are cut. It is inferred that distension of the foregut stimulates stretch receptors which, acting via the posterior pharyngeal nerves, the frontal connectives and the brain, cause the release of hormone from the storage lobes of the corpora cardiaca. This hormone acts on the terminal sensilla of the palps, causing them to close and so increasing the resistance across the palps. Release of the diuretic hormone is controlled via the same pathway.
On the Suggestion that the Secretion from the Metathoracic Scent Glands of A Surface-Dwelling Aquatic Insect, Gerris Najas (De Geer), (Heteroptera; Gerridae) Has A Waterproofing Function
Authors: Staddon B. W. 
Published: April 2021

ABSTRACT
Experiments have been carried out which give no support to the suggestion that the secretion from the metathoracic scent glands of the pond skater Gerris najas has a waterproofing function. The ability of the hair pile to resist wetting by surface forces was determined by treatment with graded solutions of pure methyl alcohol in water. In experiments of up to 7·5 weeks duration it was found that the hydrofuge hair pile of insects with sealed scent gland openings was no less resistant to wetting by surface forces than that of the controls.
Osmoregulation in the Larva of the Marine Caddis Fly, Philanisus Plebeius (Walk.) (Trichoptera)
Authors: Leader John P. 
Published: April 2021

ABSTRACT
The larva of Philanisus plebeius is capable of surviving for at least 10 days in external salt concentrations from 90 mm/l sodium chloride (about 15% sea water) to 900 mm/l sodium chloride (about 150% sea water). Over this range the osmotic pressure and the sodium and chloride ion concentrations of the haemolymph are strongly regulated. The osmotic pressure of the midgut fluid and rectal fluid is also strongly regulated. The body surface of the larva is highly permeable to water and sodium ions. In sea water the larva is exposed to a large osmotic flow of water outwards across the body surface. This loss is replaced by drinking the medium. The rectal fluid of larvae in sea water, although hyperosmotic to the haemolymph, is hypo-osmotic to the medium, making it necessary to postulate an extra-renal site of salt excretion. Measurements of electrical potential difference across the body wall of the larva suggest that in sea water this tissue actively transports sodium and chloride ions out of the body.
The Effects of Sodium-Free Solutions on the Fast Action Potentials ofViviparus Contectus(Millet) (Gastropoda: Prosobranchia)
Authors: Sattelle D. B. 
Published: April 2021

ABSTRACTA 2 h exposure of connectives of Viviparus contectus to sodium-free Ringer, in which dextran maintains osmolarity, results in a decline in the conduction velocity of the fast axons to 50% of the value obtained in normal Ringer. The changes in conduction velocity of the fast axons in response to the replacement in stages of the sodium salts of normal Ringer correspond to those exhibited by conventional excitable cells when tris is the substitute, but depart considerably from this behaviour when dextran is the substitute. Experiments employing mannitol, sucrose, raffinose, inulin and dextran to replace the sodium salts of normal Ringer reveal that dextran alone of these nonelectrolytes maintains fast action potentials in the absence of sodium. Weight losses of connectives under sodium-free (isosmotic) conditions are greatest and are most rapidly achieved when dextran (of the range of non-electrolytes studied) replaces the sodium salts of normal Ringer. Adjusting to isotonic conditions (8 mM dextran) does not diminish the ability of this non-electrolyte to maintain fast action potentials. During prolonged perfusion of connectives by tris Ringer brief (5 min) exposures to dextran Ringer at 15 min intervals rapidly restore fast action potentials. The decline of conduction velocity in these restored fibres closely follows the normal pattern of decline when function is maintained continuously in dextran Ringer.
A Field Study of Flight Temperatures in Moths in Relation to Body Weight and Wing Loading
Authors: Bartholomew George A. , Heinrich Bernd 
Published: April 2021

ABSTRACT
Flight temperatures were measured in representatives of ten families of moths-Sphingidae, Noctuidae, Geometridae, Arctiidae, Saturniidae, Ctenuchidae, Peri-copidae, Lasiocampidae, Notodontidae and Pyralidae. In all cases thoracic flight temperatures and abdominal flight temperatures were higher than ambient, and thoracic temperatures far exceeded abdominal temperatures. Within the individual species, thoracic flight temperature was relatively uniform, and independent of ambient temperatures from 7 to 17 °C. Within the various families, flight temperature was independent of body weight except in the Ctenuchidae and Arctiidae; in these two closely related families, in contrast to all the others, body weight and wing loading were positively correlated. When the families are considered as units, mean thoracic flight temperature increased with mean body weight. Between species in the same family and between families thoracic flight temperatures increased directly with wing loading. However, because thoracic flight temperature is affected by insulation and body weight, species with the same wing loading but belonging in different families may have markedly different flight temperatures. Members of those families that have high flight temperatures and must undergo a pre-flight warm-up have attributes that reduce vulnerability to predation when at rest-threat display, death feigning, production of noxious secretions, and mimicry of stinging insects.
Flapping Flight of the Andean Condor in Nature
Authors: McGahan Jerry 
Published: April 2021

ABSTRACT
At air speeds approximating to those of equilibrium gliding (14–15 m/sec), flapping by Andean condors acts to reduce sinking speed and does so without increasing forward air speed. Apparently the flapping wing provides lift by increasing the speed of the air striking its surfaces and by twisting at the same time so as to present airfoils with optimum orientation toward the changing direction of the relative wind throughout the cycle. Positive or negative components of lift and thrust forces are produced in various combinations depending on the angle of attack. Thrust forces appear at reduced air speeds, a normal condition in take off. In level flight the average velocity of the wind around the wing is greater during the downstroke than during the upstroke because of the anterior rotation of the downstroke axis. Mechanical efficiency of the lever system operating in a wingbeat is greatest during the downstroke so this orientation is important for producing maximum lift forces. The minimum power output generated by a startled condor in escape flight was computed to be 54 W/kg muscle. Assuming (a) the ratio of power output for exceptional and sustained efforts by human muscle (40:17) is similar to that of the condor and (b) the mechanical efficiency for exceptional and sustained efforts is similar, then approximately 23 W/kg wing muscle are available, only about 70% of that estimated as necessary for sustained flight in still air. On the basis of flight performance and of differences in physical dimensions the turkey vulture appears to be capable of more extended flights in still air than the condor.
Two Rates of Relaxation in the Dorsal Longitudinal Muscle of A Leech
Authors: Miller Jennifer B. , Aidley D. J. 
Published: April 2021

ABSTRACT
Experiments were performed to measure the mechanical properties of a preparation of the dorsal body wall of the leech Haemopis sanguisuga. A quantitative histological description of this preparation is provided. It is concluded that the fibres of the dorsal longitudinal muscle are almost entirely responsible for the contractile properties of the preparation, as measured along its longitudinal axis. The preparation was subjected to two types of electrical stimulation. Pulsed stimulation produced a fairly rapid contraction and relaxation. Contraction after a d.c. stimulus was slightly slower, and the relaxation consisted of an initial rapid phase followed by a much slower phase. The extent of the residual tension in this second phase was greater at higher stimulus intensities. The muscle showed some degree of fatigue when subjected to a series of stimuli. Each type of electrical stimulus caused fatigue of both responses. Curare had no effect on relaxation rates. Both phases of relaxation were somewhat slower in the presence of a high concentration of magnesium ion or γ-amino butyric acid, and faster in the presence of 5-hydroxytryptamine. It was thus not possible to separate the two types of response by pharmacological means. The mechanism whereby two rates of relaxation are produced is discussed. It is suggested that d.c. stimulation affects excitation-contraction coupling in some way.
Body-Weight, Energetics, and the Determination of Body Temperature
Authors: McNAB Brian K. 
Published: April 2021

ABSTRACT
An analysis of the influence of body weight on the energetics of endotherms has been proposed by McNab (1970). It was based on the observations that (1) when body temperature is constant heat production equals heat loss, and (2) heat loss may be described as the product of thermal conductance and the temperature differential between the body and the environment: M = C(Tb–Ta). This expression with some misfortune and inappropriateness has come to be called Newton’s law of cooling. Its application means that the energetics of an endotherm has a limited number of degrees of freedom; at a particular environmental temperature, fixing two of the factors will determine the third. It was argued that thermal conductance and the rate of heat production vary with body size and with ecological conditions. Consequently, these factors are mainly responsible for setting the level of body temperature.
Oxygen Dissociation Curves of the Blood of the Tench, Tinca Tinca
Authors: Eddy F. B. 
Published: April 2021

ABSTRACT
Oxygen dissociation curves of tench (Tinca tinca) blood were constructed for fish which had been acclimated to 5, 13 or 20 °C for at least 3 weeks. Compared to the blood of an active fish such as the rainbow trout tench blood, has a high affinity for oxygen; at 13 °C and a of 2–3 mmHg the blood was half saturated with oxygen at a of 4 mmHg. Increasing temperature, increasing and increasing hydrogen ion concentration decreased the oxygen affinity of the blood. At low temperatures the blood had an elevated pH value compared to blood at high temperatures. This is discussed in terms of the temperature dependence of ionization constants, in particular that of water. The Bohr effect and the factors influencing the loading and unloading tensions of oxygen in tench blood are discussed. The role of the blood in respiration and some properties of fish haemoglobins are also discussed.
On the Respiration of the Killifish Oryzias Latipes
Authors: Umezawa Shun-Ichi , Watanabe Hideki 
Published: April 2021

ABSTRACT
It has been shown that many factors are involved in determining the metabolic rate of an individual fish (Fry, 1957; Hughes & Shelton, 1962). The rate of respiration, for example, is influenced not only by environmental factors such as temperature and the concentration of dissolved oxygen and carbon dioxide, but also by such complicated physiological and ecological features as the size, activity and history of the fish, and external stimuli, e.g. light and sound.
Power Input During Flight of the Fish Crow, Corvus Ossifragus
Authors: Bernstein Marvin H. , Thomas Steven P. , Schmidt-Nielsen Knut 
Published: April 2021

ABSTRACT
The fish crow and the laughing gull, although similar in body mass, differ in wing morphology and wingbeat frequency. We studied the power input during sustained flight in the fish crow for comparison with data reported for the laughing gull. Two fish crows (mean mass 275 g) were trained to fly in a wind-tunnel for 15 − 20 min at air speeds of 7 − 11 m s-1 in descending flight at angles of 2 °, 4 ° and 6 ° relative to horizontal. Oxygen consumption was determined by analysing air sampled through a mask and attached trailing air tube. Power input was defined as the rate of metabolic energy expenditure calculated from rate of oxygen consumption. The results were corrected for the drag of the mask and tube, and power input for horizontal flight was calculated. Power input varied little with air speed, but decreased with increasing angle of descent. Minimum power input for horizontal flight (0.083 W g-1) was 6.4 times greater than mean resting power input. During horizontal flight, power input for the fish crow exceeded by about one-third that for the laughing gull.
Membrane Control of Ciliary Activity in the Protozoan Euplotes
Authors: Epstein Miles , Eckert Roger 
Published: April 2021

ABSTRACT
Membrane control of ciliary activity in the protozoan Euplotes was investigated by a combination of electrophysiological and cinematographic techniques. The anal cirri, which are quiescent in the absence of stimulation, were selected for this study. Membrane depolarization by means of injected current produced a reversal of the direction of beating (i.e. towards the cell anterior so as to make the ciliate swim backwards). Depolarization also increased the frequency of beating. Increasing depolarizations resulted in an increased number of reversed beats and increased frequency. When the membrane potential was shifted beyond + 70 mV, reversed beating did not occur until after the current pulse ended. Depolarization did not evoke reversed beating when the external calcium (Ca) concentration was reduced to 10−6 M with EGTA. Hyperpolarization caused the cirri to beat in a normal direction (i.e. towards the rear of the ciliate so as to cause the animal to swim forward). Increasing hyperpolarizations resulted in an increased number of forward beats and an increased frequency. The cell was treated with the detergent Triton X-100 to permit Ca, Mg and ATP direct access through the extracted membrane to the cell interior. At Ca concentrations below 10−7 M, Mg-ATP-reactivated cilia of Triton-extracted cells beat normally. At Ca concentrations above approximately 10−7 M the reactivated beat resembled the reversed beat in the living cell. The evidence suggests that membrane-regulated concentrations of intracellular Ca control the direction of ciliary beating. Thus, stimuli which produce an adequate Ca influx lead to ciliary reversal.
The Eye Muscle of Calliphora Vomitoria L.
Authors: Patterson John 
Published: April 2021

ABSTRACT
A muscle attached to the medial edge of the compound eye is described for the blowfly Calliphora-vomitoria. Electrophysiological activity in the form of continuous tonically firing potentials can be recorded extracellularly from the muscle. These potentials are generated by the muscle and have the same origin as the ‘clock-spikes’ recorded previously from the optic lobe of Calliphora erythrocephala. The interspike interval of the eye muscle potentials varies inversely with the ambient temperature. Light-adaptation results in a decrease and dark-adaptation an increase in the resting interspike interval of the eye-muscle potentials. Light-adaptation is correlated with increase and dark-adaptation with decrease in the depth of the compound eye as measured at the insertion of the muscle. The pseudopupil produced by illumination of the compound eye from the inside displays spontaneous movements which can be correlated with the anatomicall arrangement and spontaneous activity of the eye muscle. The probable function of spontaneous and transient changes in eye-muscle activity is to promote scanning of the visual images produced by the dioptrics of the compound eye.
The Eye Muscle of Calliphora Vomitoria L
Authors: Patterson John 
Published: April 2021

ABSTRACT
Changes in the intensity of the illumination falling on the compound eye produce transient changes in the interspike interval of the tonic potentials generated by the eye muscle of Calliphora vomitoria. These changes are distinct and frequently different in direction from changes in resting activity produced by light and dark adaptation which have been described previously. The effect of ‘light-on’ at high stimulus intensities is to produce a transient increase in the interspike intervals of the eye-muscle potentials. At lower intensities the result is a transient decrease in the interspike intervals. ‘Light-off’ consistently evokes a decrease in the interspike interval, and the magnitude of the decrease is graded with the logarithm of the preceding light intensity. With high-intensity stimuli changes in the interspike intervals occur within 200 msec of a change in illumination and continue to develop for at least 2 sec. The interspike intervals have returned to near to the pre-stimulus values within 30 sec to 2 min of the onset of the stimulus. The behaviour of the eye-muscle system is described for ‘near-threshold’ stimuli and response ‘threshold’ is found to vary with adapting intensity in a way which illustrates a Weber-Fechner relationship.