bluuebunny/crossref_metadata_2025_split huggingface dataset:
Absence Penalties and Work Attendance
Authors: Balchin Jeffrey , Wooden Mark 
Published: January 2008

AbstractThis article extends previous economic treatments of the work attendance decision by providing a more complete specification of the absence penalty function. In particular, the penalty for absence is modelled as a function of both the opportunity cost of dismissal for excessive absence and the level of threat of dismissal chosen by management to control absence. Moreover, since the probability of dismissal is itself a function of the absence rate, a simultaneous system is posited. Strong support for the model is found in workplace‐level data collected as part of the 1989–90 Australian Workplace Industrial Relations Survey.
Are Terms of Trade Rises Inflationary?
Authors: Gruen David , Dwyer Jacqueline 
Published: January 2008

AbstractThis article explores the relationship between the terms of trade and inflation. It shows, both analytically and empirically, that the exchange rate response to a change in the terms of trade is crucial to the inflation outcome. It demonstrates the existence of a ‘threshold’ exchange rate response. Our best estimate is that a rise in the terms of trade is inflationary if the associated rise in the real exchange rate is less than about 1/3–1/2 of the rise in the terms of trade. However, if appreciation of the real exchange rate is larger than this, the consequent fall in the domestic price of importables is large enough that the terms of trade rise reduces inflation, at least in the short run.
DIE ROTFÄRBUNG VON HOCHGEBIRGSSEE‐ORGANISMEN
Authors: BREHM Von V. 
Published: January 2008

ZusammenfassungIn Hochgebirgsseen treten auf der ganzen Erde wie auch in den Gewässern der Polarzone bei bestimmten Tiergruppen rote Pigmente auf, über deren Entstehung und Bedeutung im Laufe der letzten 50 Jahre verschiedene Ansichten geäussert wurden. Die elf hierüber aufgestellten Hypothesen werden in konkreten Fällen angeführt und zur Discussion gestellt, da keine dieser Annahmen experimentell gestützt ist und demnach alle der Nachprüfung von chemischer und physiologischer Seite bedürfen.SummaryRed pigments are found in certain groups of animals occurring in mountain lakes in all parts of the world and in polar waters. In the course of the last half century various opinions have been expressed concerning the origin and significance of this red coloration. In this article eleven hypodieses have been reviewed. None of these has an experimental basis and all therefore require to be tested chemically and physiologically.
HORMONES IN CRUSTACEA
Authors: KLEINHOLZ L. H. 
Published: January 2008

SummaryColour changes in crustaceans are controlled by a secretion originating in the eye‐stalk. The glandular tissue is probably Hanström's sinus gland, although the X‐organ may also be concerned in this function. Retinal pigment migration is similarly regulated by a hormone from the eye‐stalks. Physiological evidence points to the existence of at least two pigmentary hormones, one for the chromatophores and another for the retinal pigment. No conclusion can yet be made concerning the exact numbers of these hormones. Cyclic activity of these pigmentary effectors under constant environmental conditions is explained on a nervous‐hormonal basis.There is no evidence that calcium metabolism is under specific hormonal control. The reserve pre‐moulting calcium may be regulated by an eye‐stalk hormone that is also suspected of inhibiting ecdysis. The viability effect reputedly regulated by eye‐stalk hormone may be due to nervous injury rather than to a specific active substance.Maintenance of the secondary sex characters has been thought to be controlled by the sex hormones. The evidence, coming chiefly from studies of parasitic and radiation castrations, is not wholly reliable because of metabolic disturbances introduced under these conditions. Direct evidence from injection of glandular extracts is lacking.
THE EVOLUTION OF EPIPHYSES AND OF ENDOCHONDRAL BONE
Authors: HAINES R. WHEELER 
Published: January 2008

Summary1. The most primitive type of epiphysial mechanism known is found in bony fishes, and from this type all others are easily derivable. The cartilaginous epiphyses contain a mass of undifferentiated cells, a growth zone of flattened cells, and a zone of hyper‐trophied cells derived from them. Endochondral bone and marrow are well developed. Temporary cessation of growth may occur with loss of differentiation in the growth zone and the formation of a closing plate of endochondral bone shutting off the marrow from the epiphysial cartilage.2. In some modern fishes, Chondrostei and Dipnoi, endochondral bone and marrow have been lost, in others a secondary centre of calcification may be found in the epiphysis, but these changes are peculiar specializations.3. In primitive tetrapods, including all typical early fossil forms and the living Crocodilia and Chelonia, the cells of the growth zone are arranged more or less regularly in columns, and the endochondral bone, guided by these columns, again has a regular arrangement.4. Of the modern amphibians the Urodela have lost the regular arrangement of the cells of the growth cartilage, and have reduced the amount of their endochondral bone, while the Anura have developed a peculiar match‐head type of epiphysis with a calcified secondary centre.5. In Sphenodon a large calcified secondary centre is developed between the articular cartilage and the growth cartilage. By separating these cartilages it allows each to adopt the most advantageous position, the one for the formation of the joint surface, and the other for directing the arrangement of the trabeculae of the endochondral bone.6. All other groups are specialized in one direction or another. Bony secondary centres which strengthen the epiphyses are found in typical Lacertilia except in some small forms which have lost them, in the tibia of Aves and in Mammalia. Cartilage canals, developed primarily for the nutrition of the cartilaginous epiphyses, are found in Varanidae, Aves and Eutheria, and possibly in Anura, while the Monotremata have a very peculiar cartilage canal system whose development is not yet understood. These features are the result of very detailed parallelisms in evolution.7. Intratendinous centres of ossification, formed by ossification of tendons where these are inserted into epiphysial cartilage, are distinguished structurally from typical epiphysial centres.
THE PRESENT STATUS OF THE NEURONE THEORY
Authors: NONIDEZ JOSÉ F. 
Published: January 2008

SummaryDuring the last decade certain authors have considered the classical neurone theory to be obsolete and have resuscitated the long‐rejected hypothesis of a nervous syncytium, mainly on histological evidence. Bauer believes in connexions between embryonic neuroblasts, serving as pathways for the growth of nerve fibres which thus develop intraprotoplasmically. This concept must be regarded as entirely hypothetical. Anastomoses found between neuroblasts and nerve fibres growing in tissue culture are emphasized by the reticularists, but this is not overwhelmingly against the neurone theory since such anastomoses are by no means universal and they depend on the part of the nervous system cultured and on the properties of the medium. Claims by Bauer on the continuity of nerve cells with each other and with neuroglia disagree with the demonstrated existence of free dendrites and of synapses withneurones. Reticularists also maintain the continuity of neurones in the autonomic system, but this too is open to serious criticism on histological grounds. Moreover, autonomic ganglia afford good material for the demonstration of synaptic endings both in ‐fixed and living preparations. The reality of independent neurones is confirmed by the degeneration of synaptic boutons in the central nervous system after the destruction of nerve tracts, and by the degeneration and regeneration of preganglionic fibres in autonomic ganglia, in which the loss and recovery of function are confirmed experimentally. The existence of the synapse in confirmed by the delay in impulse transmission, varying with the type of synapse, and by the nicotine block to impulses from preganglionic fibres to autonomic ganglia. The recent criticisms of the neurone theory are based on preparations made exclusively by the Biel‐schowsky technique, unsupported by experimental work, and the several workers disagree widely in their evidence. Boeke claims that the finer divisions of the autonomic system contain a meshwork of neurofibrils clearly distinguishable from the surrounding connective tissue; this structure is not found, however, with other neurofibrillar methods but appears with silver carbonate which does not stain nervous structures. Stohr believes in a fine terminal reticulum of the autonomic and sensory systems surrounding every cell in the body. Again other competent histologists, working with techniques which do not stain connective tissue fibres, have failed to confirm Stohr, whose claims are moreover unsupported experimentally. The reticularists cannot agree among themselves on their substitute for the neurone theory and it would seem wise to retain this concept until better proof is offered of the syncytial nature of the nervous system.
PIGMENTS IN THE COELENTERATA
Authors: FOX D. L. , PANTIN C. F. A. 
Published: January 2008

Summary(i) The nature, variety and significance of coelenterate pigments is discussed. They may be grouped under: miscellaneous pigments, the pyrrolic series, purines, melanins, carotenoids. (2) The nature of several well‐known pigmentations is not fully understood. Chief of these are the deep blues and browns of pelagic coelen‐terates, possibly due to carotenoid‐protein compounds; and the remarkable stable colours of the spicules of Alcyonaria. The latter appear to be combined with calcium and iron. (3) Of the pyrrolic series haematins are common. They play little part in coloration and are probably simply part of the intracellular respiratory system. Bile pigments also occur and attention is drawn to the interesting pigment of this kind present inCalliactis parasitica.(4) Purines only contribute white to the colour pattern of some anemones. They occur as uric acid and possibly as other purines. (5) Black and brown melanins occur inMetridium senileand probably in other anemones. Even white anemones may possess a complete tyrosinase system. (6) It seems that coelenterate colours are due chiefly to carotenoids. These are found in species from all parts of the phylum. Though the evidence is incomplete, the carotenoids are in some cases known to be derived from the food (Hydra, actinians). Sometimes at least, however, they are altered to ‘animal’; carotenoids, as in the ‘metridene’ fromMetridium.Different colour varieties may form chemically different carotenoids. (7) Detailed study of actinians shows a surprisingly complex pigment situation. An individual may possess several distinct carotenoids, and different varieties of the same species are characterized by different series of pigments. (8) Little is known of the biochemical significance of the pigments. There are indications that the presence of carotenoids is in some cases related to light intensity. There is also evidence that these pigments are of importance in gamete formation and in regeneration. The biochemical significance of the varietal colour differences is not known. Attention is drawn to Stephenson's observations on the importance of range of colour and of colour pattern in relation to morphological axes of differentiation. (9) The genetic significance of the existence of colour varieties is discussed. True polymorphism with respect to colour is common in coelenterates. No genetic explanation can be offered without further experiment. The resemblance of the colour systems ofMetridiumto the blood group systems in man is commented on. Attention is drawn to the widespread character of colour polymorphism in the lower invertebrates.
PREDATOR VIGILANCE AND GROUP SIZE IN MAMMALS AND BIRDS: A CRITICAL REVIEW OF THE EMPIRICAL EVIDENCE
Authors: ELGAR MARK A. 
Published: January 2008

SummaryOne commonly cited benefit to animals that forage in groups is an increase in the probability of detecting a predator, and a decrease in the time spent in predator detection. A mathematical model (Pulliam 1973) predicts a negative relationship between group size and vigilance rates. Over fifty studies of birds and mammals report a negative correlation between group size and vigilance behaviour and most conclude that the relationship at least partly explains why individuals forage in groups. This review evaluates the strength of these conclusions based on their evidence. Those variables that may confound the relationship between vigilance and group size are outlined, and their control is assessed for each study. The variables I consider to be important include the density and type of food; competition between individuals; the proximity to both a safe place and the observer; the presence of predators; the visibility within the habitat; the composition of the group; the ambient temperature and the time of day. Based on these assessments, most of the studies fail to adequately demonstrate an unambiguous relationship between vigilance behaviour and group size. Nevertheless, many studies reveal interesting features of the relationship between vigilance and group size that should provide fruitful avenues for future research.
DIFFERENCES IN THE FORAGING OF JUVENILE AND ADULT BIRDS: THE IMPORTANCE OF DEVELOPMENTAL CONSTRAINTS
Authors: MARCHETTI KAREN , PRICE TREVOR 
Published: January 2008

SummaryJuvenile birds differ from conspecific adults in their diet and methods of prey capture and prey handling. Juvenile‐adult differences in foraging result from (1) immaturity of the beak, skeleto‐muscular and neurological systems and (2) the time required to learn foraging skills. These conclusions are largely based on field observations. More experimental studies to assess the relative importance of the various constraints are needed.Juvenile birds appear to be under strong selection to reach adult form and function as rapidly as possible. Remaining differences between juveniles and adults are largely attributable to constraints. In contrast to many other taxa there are few examples in which juvenile‐adult differences in foraging have been accentuated by selection on the juvenile behaviours.
THE INFLUENCE OF BENSERAZIDE ON CHANGES IN MONOAMINE OXIDASE ACTIVITY IN SOME RAT TISSUES FOLLOWING TREATMENT WITH L‐DOPA
Authors: CALLINGHAM B. A. , LYLES G. A. 
Published: January 2008

This study was designed to see whether or not increases in monoamine oxidase (MAO) specific activity that follow chronic treatment of rats with L‐dihydroxyphenylalanine (L‐DOPA) could be modified by benserazide (Ro 4‐4602), an inhibitor of L‐aromatic amino acid decarboxylase, and to compare the properties of the increased MAO activity with those of control animals.
Male Wistar rats were treated with L‐DOPA (250 mg/kg) and benserazide (40 mg/kg) either alone or in combination for 10 days.
The activity of MAO in homogenates of heart, kidney, liver and brain was measured with 5‐hydroxytryptamine (5‐HT) and benzylamine (BZ).
The significant increases in MAO specific activity seen in heart and kidney following L‐DOPA treatment could be reduced or prevented by benserazide.
Use of the selective MAO inhibitor clorgyline showed that the increases in MAO specific activity, when measured with either 5‐HT or BZ were due to an increase in the number of active centres of MAO‐A, in the rat heart.
There was a significant increase in the V max of the enzyme reaction with 5‐HT, in the rat heart and kidney homogenates.
It is concluded that L‐DOPA increases the specific activity of MAO‐A in rat heart and kidney as a result of its decarboxylation.
THE EFFECTS OF SOME DOPAMINE ANTAGONISTS ON CHOLINERGIC MECHANISMS IN THE GUINEA‐PIG ILEUM
Authors: FOSBRAEY P. , HIRD M. F. , JOHNSON E. S. 
Published: January 2008

Activation of prejunctional muscarinic and opiate receptors on cholinergic neurones of the guinea‐pig ileum by acetylcholine (ACh) or morphine was seen as an inhibition of twitch responses to transmural electrical stimulation. These inhibitory responses were antagonised by metoclopramide and DL308‐IT but no other antagonist used blocked the morphine responses apart from sulpiride in very high concentrations (100 μM and above).
Prejunctional and postjunctional responses to ACh on the guinea‐pig ileum were measured in the presence of increasing concentrations of some muscarinic and dopamine antagonists. Atropine, hyoscine, chlorpromazine, cis‐flupenthixol and thioridazine showed no selectivity in their antagonism of either response to ACh. Benzhexol selectively antagonised the postjunctional response whereas metoclopramide and DL308‐IT showed greater selectivity for the prejunctional effect which they antagonised competitively. Sulpiride, a compound chemically related to metoclopramide, blocked neither the prejunctional nor postjunctional ACh responses. Clozapine antagonised the postjunctional ACh responses whilst apparently potentiating the prejunctional inhibition by ACh.
It was concluded that pharmacological differences may exist between prejunctional and postjunctional muscarinic receptors for ACh and that the antipsychotic actions of dopamine antagonists are unlikely to involve blockade of prejunctional ACh or opiate receptors.
EFFECTS ON BLOOD PRESSURE OF NORADRENALINE AND ISOPRENALINE ADMINISTERED INTO THE THIRD VENTRICLE OF THE BRAIN OF ANAESTHETIZED AND CONSCIOUS CATS
Authors: DAY M. D. , POYSER R. H. , SEMPIK J. 
Published: January 2008

Noradrenaline administered into the third ventricle of the brain (IIIv) of both conscious and anaesthetized cats induced increases in blood pressure accompanied by small and variable heart rate effects. The pressor responses were reduced after autonomic ganglion blockade indicating their likely central origin.
Noradrenaline when administered either into a lateral cerebral ventricle (i.c.v.) in conscious and anaesthetized cats or into the cisterna magna (i.c.) in anaesthetized cats induced falls in blood pressure accompanied by bradycardia.
Pressor responses to IIIv noradrenaline in conscious cats were partly blocked by either propranolol or thymoxamine indicating a possible involvement in the responses of excitatory adrenoreceptors of both α and β types.
Pressor responses induced by IIIv isoprenaline in conscious cats were blocked by propranolol but not by thymoxamine suggesting the effect is mediated solely via excitatory β‐adrenoreceptors.
In anaesthetized cats prior i.c. administration of noradrenaline reduced the pressor responses induced by IIIv noradrenaline.
In conscious cats i.v. clonidine reduced pressor responses to IIIv noradrenaline without depressing peripheral vascular noradrenaline sensitivity.
The results suggest the involvement of excitatory and inhibitory α‐adrenoreceptors and of excitatory β‐adrenoreceptors in central blood pressure control. It is also concluded that activation of inhibitory α‐adrenoreceptors in the hind brain region can suppress the cardiovascular effects of stimulating excitatory α‐ and β‐adrenoreceptors located in the region of the third ventricle.
FACTORS INFLUENCING THE MAGNITUDE AND DURATION OF RESPONSES TO ENDOGENOUS AND EXOGENOUS NORADRENALINE IN RABBIT PULMONARY ARTERY AND PORTAL VEIN
Authors: PATON D. M. 
Published: January 2008

In the rabbit portal vein, cocaine potentiated responses to (–)‐noradrenaline, and prolonged relaxation following transmural stimulation. Neither process was altered by hydrocortisone and U‐0521, oxytetracycline or 4‐aminopyridine alone or in combination with cocaine. These findings indicated that neuronal uptake was principally responsible for the inactivation of noradrenaline in this tissue.
In the rabbit pulmonary artery, the rate of relaxation following transmural stimulation was prolonged by cocaine and by hydrocortisone and U‐0521, and further prolonged by the combination of all three drugs. These findings suggest that both neuronal and extra‐neuronal uptake are responsible for the inactivation of noradrenaline in this tissue.
4‐Aminopyridine potentiated responses to (–)‐noradrenaline and prolonged relaxation after transmural stimulation in pulmonary artery possibly as a consequence of a postjunctional action in this tissue.
The rabbit portal vein was less sensitive to (–)‐noradrenaline and relaxed more after transmural stimulation than the pulmonary artery. It is suggested that this reflects the denser noradrenergic innervation and smaller neuromuscular distance present in the portal vein.
THE USE OF THE RAT RIGHT VENTRICLE STRIP IN STUDIES ON NORADRENERGIC TRANSMISSION
Authors: DOGGRELL SHEILA A. , VINCENT LYNN 
Published: January 2008

The possibility of using contractility studies with the rat right ventricle strip to assess the effects of drugs on all aspects of noradrenergic transmission has been examined.
The force of the contractile responses to field stimulation at 0.5 and 2, but not 5 Hz, markedly decreased with time. About 55% of the tissues responded directly to (−)‐isoprenaline, 1 × 10−6M (123 tissues from 220 tested) in the absence of other stimuli. In these tissues the force of the contractile responses remained constant and the rate increased with time. Thus it is essential to provide time controls in studies with rat right ventricle.
Under conditions in which the responses to (−)‐isoprenaline, 1 × 10−6M, alone were unaffected the responses to field stimulation at 5 Hz were inhibited by 66 and 86% by 9 × 10−6M tetrodotoxin and 1 × 10−5M guanethidine, respectively. (+)‐Propranolol and timolol (both at 1 × 10−6M), but not phentolamine, 1 × 10−6M, inhibited responses to (−)‐isoprenaline, 1 × 10−6M alone and responses to field stimulation at 5 Hz. This demonstrates that the responses to field stimulation are largely due to activation of noradrenergic nerves, the released noradrenaline acting at postsynaptic β‐adrenoreceptors.
Although nortriptyline is a potent inhibitor of the neuronal uptake of noradrenaline, at 1 × 10−6M it had no effect on the contractile responses to field stimulation at 5 Hz and inhibited responses to (−)‐isoprenaline, 1 × 10−6M, alone and at a higher concentration (1 × 10−5M) nortriptyline abolished both responses. It is suggested that the rat right ventricle preparation may be useful in examining the effects of drugs on noradrenergic transmission in the heart.
CENTRAL CATECHOLAMINERGIC LESIONS IN THE DEVELOPING RAT: EFFECTS ON CARDIAC NORADRENALINE LEVELS, TURNOVER AND RELEASE
Authors: DESKIN R. , SLOTKIN T. A. 
Published: January 2008

The role of the central nervous system in regulating cardiac sympathetic tone was examined in developing rats with neonatal central catecholaminergic lesions produced by intracisternal 6‐hydroxydopamine treatment.
Lesioned animals showed a persistent deficit in both cardiac noradrnaline levels and spontaneous turnover rate as evaluated by alpha‐methyl‐p‐tyrosine treatment.
Despite these deficits, tyramine was fully capable of releasing cardiac noradrenaline and short‐term centrally‐mediated release also could be elicited by exposure to cold or by swimming exercise.
The alterations in cardiac noradrenaline content produced by the central lesions may result from long‐term reductions in sympathetic tone which do not necessarily compromise short‐term response capabilities of the sympathetic system.