bluuebunny/crossref_metadata_2025_split huggingface dataset:
WATER‐REGULATORY BEHAVIOUR IN TERRESTRIAL GASTROPODS
Authors: PRIOR DAVID J. 
Published: January 2008

Summary1. Terrestrial snails and slugs are exceedingly susceptible to dehydration due to evaporative water loss from the integument and lung surface, and the deposition of a dilute mucous trail. Active slugs can lose 30–40% of their initial body weight (IBW) within 2 h.2. Both field and laboratory studies have revealed that habitat selection by snails and slugs is well correlated with the availability of water. In addition, numerous species display homing behaviour, returning directly to their moist secluded daytime resting sites at dawn.3. Several aspects of locomotor activity are affected by body hydration and environmental conditions such as relative humidity. Moist conditions result in termination of aestivation in snails and a generally higher level of activity in both snails and slugs. In contrast, severe dehydration initiates aestivation in snails and an increase in the intensity and duration of circadian locomotor activity in slugs.4. Huddling behaviour is a specialized example of the general preference of slugs for moist habitats. When groups of slugs are exposed to dry environmental conditions, they form closely packed aggregations. This response results in a decrease in the rate of dehydration of the individual slugs.5. When slugs have been dehydrated to about 90% IBW, rhythmic closures of the pneumostome are initiated. As dehydration progresses there is a reduction in the open diameter of the pneumostome. These responses reduce the total exposure of the lung surface and thereby evaporative water loss. In slugs dehydrated to about 80 % IBW, these responses can result in a 7 % reduction in water loss. 6. When slugs have been dehydrated to about 65% IBW (67·6 ± 4·3% IBW) they move on to a moist surface, assume a characteristic flattened posture and remain quiescent while water is absorbed through the surface of the foot. Once they are rehydrated (to 93·5 ± 12·4% IBW) they move off the moist surface. Thus there exists a specific dehydration threshold for the initiation of contact‐rehydration and a rehydration set‐point at which the response is terminated.7. Both initiation and termination of contact‐rehydration are controlled by variations in haemolymph osmotic pressure. The behaviour can be experimentally initiated by injection of hyperosmotic mannitol solution and terminated by injection of dilute saline.8. Contact‐rehydration involves bulk flow of water through an epithelial paracellular pathway in the integument of the foot. The rate of absorption of [14C]inulin during contact‐rehydration is similar to that of water. The efficacy of water movement through the pathway is modulated by body hydration, the pathway being opened only in dehydrated slugs.9. By means of the dual‐limit control of contact‐rehydration slugs can behaviourally regulate their body hydration and haemolymph osmolality within the tolerable hydration range described by the upper and lower limits.
THE ORIGIN OF THE SPINNING APPARATUS IN SPIDERS
Authors: SHULTZ JEFFREY W. 
Published: January 2008

Summary

Previous attempts to explain the evolution of spider silk have relied heavily on conjecture. The formulation of testable historical hypotheses to replace such speculation is discussed.
The importance of phylogenetic reconstructions and other historical hypotheses for use in generating and testing hypotheses concerning the evolution of specific adaptations is examined. Recent ideas on arachnid phylogeny are reviewed and their relevance to the problem of silk evolution in spiders is explored.
Evidence from the analysis of three historical problems (origin of spinnerets, origin of silk glands, original selective pressure favouring evolution of silk) is reviewed from three different frames of reference (in‐group analysis, out‐group analysis, convergence analysis). Several lines of evidence are found which suggest that silk use originated in spiders due to selective pressures associated with reproduction (specifically, the transfer of sperm or the protection of eggs).
The prevalence of segmental appendages retained for use in manipulating genital products in both arachnids and non‐arachnid arthropods and the probable placement of spinnerets near the genital opening in ancestral spiders suggest that spinnerets represent modified gonopods.
The most primitive types of silk glands are retained in virtually all spiders, in part, for use in the construction of sperm webs and egg sacs. Similar silk glands are found near the genital opening in many male spiders and used in building a portion of the sperm web.
The silk of adult arthropods other than spiders is used largely in manipulating or protecting sex cells. If there are multiple functions, use in reproduction is typically one of them. Thus, there is evidence for strong selective pressure favouring the evolution of silk for use in reproduction.
Two hypotheses are proposed which are consistent with the conclusion that silk in spiders evolved for reproductive needs (the spermatophore‐sperm web and egg sac hypotheses). Testable predictions of each hypothesis are proposed.
OSMOREGULATION IN CROCODILIANS
Authors: TAPLIN LAURENCE E. 
Published: January 2008

Summary1. The osmoregulatory strategies of crocodilians in both saline and fresh‐water environments are discussed and dissected into their separate components.2. Contrasts between members of the Alligatoridae and the Crocodylinae emerge repeatedly in aspects such as integumental permeabilities, functioning of the renal/cloacal system, and the presence of lingual salt‐secreting glands.3. These contrasts contribute to the view that the alligatorid and crocodyline stocks are more divergent than has been suspected previously. In particular, there is cogent evidence of a significant marine phase in the evolution of the Crocodylinae but not of the Alligatoridae.4. The physiological evidence to support this view of a very basic dichotomy among the eusuchians is reviewed in detail and avenues which would contribute most to its critical evaluation are identified.
COLONY FORM AND THE EXPLOITATION OF SPATIAL REFUGES BY ENCRUSTING BRYOZOA
Authors: BISHOP J. D. D. 
Published: January 2008

SummaryThe sheet‐runner continuum model of unilaminar encrusting colony growth is reassessed for cheilostome Bryozoa. It is concluded that the model does not adequately account for the existence of spatially predictable refuges from mortality, which can be selected by the larva at the time of settlement.A third end‐point category of colony form, named the spot colony, is recognized for species settling in small spatially predictable refuges and growing to small, early maturing colonies of determinate or semi‐determinate size. Similar colonies are reported from spatially restrictive substrates such as flexible algal fronds and single sediment grains on particulate seabeds.Runner growth is also reappraised. In some cases, uniserial growth may be regarded as a primary adaptation for growth in linear refuges, or on maze‐like or strongly three‐dimensional surfaces where multiserial growth is impossible, rather than as a general fugitive strategy adopted by competitively inferior forms.A revised classificatory model for encrusting growth is proposed. This consists of two continua, sheet‐ribbon‐runner and sheet‐patch‐spot. It is suggested that an improved ecological classification of encrusting growth might be framed as a series of coupled settlement/growth strategies.
EMBRYONIC RESISTANCE TO CHEMICAL AND PHYSICAL FACTORS: MANIFESTATION, MECHANISM, ROLE IN REPRODUCTION AND IN ADAPTATION TO ECOLOGY
Authors: ZUSMAN IGOR , ORNOY ASHER 
Published: January 2008

SummaryChemical and physical factors may adversely affect embryonic development. As an example of chemical factors, the effects of diabetic metabolic factors on embryonic development in mammals was reviewed. The existence of a stage‐dependent reaction of embryos was found. At preimplantation stages diabetic metabolic factors are embryotoxic and lethal, and the blastocysts reacted by an “all‐or‐none” response. Early somite embryos showed a higher resistance to the effects of diabetic metabolic factors resulting in various types of malformations. Both groups of embryos showed a very high sensitivity to the effects of combined diabetic metabolic factors. Congenital defects in term foetuses were lower than those observed during middle phases of pregnancy because some of the severely malformed embryos resorb during gestation. The effects of temperature on embryonic development were presented as an example of physical influences. In man, hyperthermia in pregnancy seems to correlate with defects in the development of the nervous and skeletal systems. In domestic animals, changes in environmental temperature correlated with depressions of reproduction rate. In laboratory animals, hyperthermia caused the development of congenital malformations. Stage‐dependent as well as genetic differences in embryonic susceptibility to hyperthermia were found. Critical periods in sensitivity of embryos to hyperthermic influences were also observed. It has been shown that, in spite of similar external manifestations of the reaction of embryos to effects of diabetes and hyperthermia, the mechanism of these reactions was different. High resistance of early reptile and bird embryos to influences of temperature was considered as an example of morpho‐functional adaptations in early embryogenesis of vertebrates to their development in terrestrial conditions.
QUANTITATIVE VARIATIONS OF NUCLEAR DNA DURING PLANT DEVELOPMENT: A CRITICAL ANALYSIS
Authors: BASSI PAOLA 
Published: January 2008

SUMMARYIn this review a critical analysis is made of the quantitative DNA variations that take place during plant development. These include underreplication, loss and amplification of repeated sequences; particular attention is devoted to quantitative variations of non‐coding DNA sequences.Examples reported in the literature are analysed in relation to the different biological phenomena they accompany such as vegetative development, phase changes, senescence, dedifferentiation or tumour formation.The author also considers the influence that external elements such as growth factors, chemical substances, culture medium composition, or, also, different stimuli of environmental character, can have on these quantitative variations of nuclear DNA sequences.Finally the different hypotheses on the role that repetitive DNA sequences (particularly those that are highly repeated) can have on the life of the cell are analysed and discussed.The experimental evidence, although fragmentary and sometimes contradictory, leads to the conclusion that the plant genome is not so ‘quantitatively static’ as was once hought, but is instead characterized by a dynamic plasticity; the role of repeated DNA sequences in the plant development seems to be much more active, than the role hypothesized by many authors in the past.
MECHANISMS OF AVIAN IMPRINTING: A REVIEW
Authors: BOLHUIS JOHAN J. 
Published: January 2008

SummaryFilial imprinting is the process through which early social preferences become restricted to a particular object or class of objects. Evidence is presented showing that filial preferences are formed not only as a result of learning through exposure to an object, but also under the influence of visual and auditory predispositions. The development of these predispositions is dependent upon certain non‐specific experience.There is little evidence for an endogenously affected sensitive period for imprinting. It is more likely that the end of sensitivity is a result of the imprinting process itself. Similarly, it is now firmly established that filial and sexual preferences are reversible. Evidence suggests, however, that the first stimulus to which the young animal is exposed may exert a greater influence on filial preferences than subsequent stimuli.The learning process of imprinting is often regarded as being different from conventional associative learning. However, the imprinting object itself can function as a reinforcer. Recent studies have attempted to test predictions from an interpretation of filial imprinting as a form of associative learning. The first results suggest that ‘blocking’ may occur in imprinting, whilst there is no evidence for ‘overshadowing’.Social interactions with siblings and parent(‐surrogates) have been shown to affect the formation of filial and sexual preferences. The influence of these interactions is particularly prominent in sexual imprinting, making earlier claims about naive species‐specific biases unlikely.Although auditory stimuli play an important role in the formation of social attachments, there is little evidence for auditory imprinting per se. Auditory preferences formed as a result of mere (pre‐ or postnatal) exposure are relatively weak and short‐lasting. Exposure to visual stimuli during auditory training significantly improves auditory learning, possibly through a process of reinforcement.It is becoming increasingly clear that filial and sexual imprinting are two different (although perhaps analogous) processes. Different mechanisms are likely to underlie the two processes, although there is evidence to suggest that the same brain region is involved in recognition of familiar stimuli in both filial and sexual imprinting.There is little evidence for a direct role of hormones in the learning process of imprinting. Androgen metabolism may be a factor constraining the development of a predisposition in the chick. Research into the neural mechanism of filial imprinting in the chick has revealed that a restricted part of the forebrain (IMHV) is likely to be a site of memory storage. Changes in synapse morphology and in the number of NMDA receptors have been found, limited to this region, and correlated with the strength of preference.
THE EVOLUTION OF EUTHERIAN SPERMATOZOA AND UNDERLYING SELECTIVE FORCES: FEMALE SELECTION AND SPERM COMPETITION
Authors: ROLDAN E. R. S. , GOMENDIO M. , VITULLO A. D. 
Published: January 2008

SumaryWe have examined sperm morphology and dimensions in Eutherian mammals. In most Eutherians, sperm heads are round or oval and spermatozoa have short tails (average sperm length about 65 μm; range = 33–121 μm). Rodents, however, clearly depart from the typical Eutherian pattern in that they show a broad array of head morphs and an extreme range of sperm dimensions (35–250 μm). In order to trace the evolutionary changes that rodent sperm have undergone, we have used phylogenetic relationships based on biogeographical, morphological, chromosomal and genic data, and we have superimposed onto them the information available on sperm traits. Analyses were carried out for five rodent groups on which enough information was available. The evolutionary trends which emerged from these studies have two main points in common throughout evolution spermatozoa have become enlarged and morphologically more complex, and this process seems to have taken place independently in different lineages. A general model was developed which outlines the different evolutionary pathways that rodent sperm have undergone.The adaptive significance of the increase in head complexity and the elongation of the sperm tail remains obscure. We have integrated information from evolutionary, physiological and behavioural studies to address this issue. We argue that two main selective forces may have favoured these changes: female selection within the reproductive tract and sperm competition. The female tract represents a formidable barrier for spermatozoa and it provides an environment where numerous interactions take place. The extent of these barriers and the complexity of these poorly understood interactions suggest that females may be exercising a strong selection, which may enable them to favour particular types of spermatozoa or ejaculates from particular males. Throughout their evolution males must have evolved adaptations to overcome these barriers, and the conflicting interests of choosy females. Sperm competition is a potent evolutionary force among mammals, which has influenced not only the evolution of sperm numbers but also changes in sperm dimensions. Thus, sperm competition has favoured the elongation of the sperm tail, which has led to the attainment of faster swimming speed, an important factor when sperm from rival males compete to reach the ova first.
THE FUNDAMENTAL THEOREM OF NATURAL SELECTION
Authors: EDWARDS A. W. F. 
Published: January 2008

The fundamental theorem of natural selection was a valiant attempt by R. A. Fisher to fit a quart into a pint potThe present author reviewing Population Genetics by Ewens, 1969a (Edwards, 1969).Many authors have maintained that the theorem holds only under very special conditions, while only a few (e.g. Edwards, 1967) have thought that Fisher may have been correct – if only we could understand what he meant! It will be shown here that this latter view is correctPrice, 1972.My own reason for not including a planned chapter on the fundamental theorem is… [that] in spite of many efforts I am still not satisfied that I am able to provide an account that does the theorem justiceThe present author in the Epilogue to Foundations of Mathematical Genetics (Edwards, 1977).
ALTERNATION OF GENERATIONS IN LAND PLANTS: NEW PHYLOGENETIC AND PALAEOBOTANICAL EVIDENCE
Authors: KENRICK ByPAUL 
Published: January 2008

SummaryCurrent ideas on the evolution of alternation of generations in land plants are reviewed in the context of important recent advances in plant systematics and the discovery of remarkable new palaeobotanical evidence on early embryophyte life cycles. An overview of relationships in major groups of green plants is presented together with a brief review of the early fossil record as a prelude to discussing hypotheses of life cycle evolution. Recent discoveries of life cycles in the early fossil record are described and assessed. The newly discovered gametophyte and sporophyte associations are based on exceptionally well‐preserved material from the Rhynie Chert, Scotland (Middle Devonian: 380–408 Myr) and compression fossils from other Devonian localities. These data document diplobiontic life cycles in plants at the ‘protracheophyte’ and early tracheophyte level of organization. Furthermore, the early fossils have a more or less isomorphic alternation of generations, a striking departure from life cycles in extant embryophytes. This unexpected similarity between gametophyte and sporophyte calls for a cautious approach in identifying ploidy level in early groups. Viewed in a systematic context, the neontological and palaeontological data contribute towards the formulation of a coherent hypothesis of life cycle evolution in major, early embryophyte groups. Evidence from extant groups strongly supports a single direct origin of the diplobiontic life cycles of land plants from haploid, haplobiontic life cycles in ancestral ‘charophycean algae’. The interest of the new palaeobotanical data lies in its relevance to life cycle evolution at the restricted level of vascular plants rather than at the more general level of embryophytes (vascular plants plus ‘bryophytes’). The occurrence of morphologically complex, axial gametophytes in early vascular plants is consistent with the moss sister‐group proposed in some cladistic analyses. Similarities of moss gametophytes to fossils in the vascular plant stem‐group are discussed, and it is argued that the late appearance of mosses in the macrofossil record may be due to the problem of recognizing stem‐group taxa. The new palaeobotanical evidence conflicts with previous hypotheses based on extant groups that interpret morphological simplicity as the plesiomorphic condition in the gametophytes of vascular plants. These new data indicate that a significant elaboration of both gametophyte and sporophyte occurred early in the tracheophyte lineage, and that the gametophytes of extant ‘pteridophytes’ are highly reduced compared to those of some of the earliest ‘protracheophytes’. Vestiges of this early morphological complexity may remain in the gametophytes of some extant groups such as Lycopodiaceae.
VARIABILITY OF NEOPLASTIC PARAMETERS IN COLON TUMOURS, AND ITS SIGNIFICANCE IN DIAGNOSTIC PRACTICE
Authors: ZUSMAN IGOR 
Published: January 2008

SUMMARYWe have reviewed the value of individual variability in the reaction of tissues to treatment with carcinogens, and the manifestation of this variability in different morphological (histological, morphometric, and ultrastructural), histochemical and immunohistochemical parameters generated in tumorous tissues. Moreover, we also reviewed data in the literature on individual variability in the manifestation of some biochemical and immunochemical markers which are accumulated in the serum of tumour‐bearing patients and which are characteristic for the different phases of tumourigenesis. The high variability of different tumorous parameters suggests that none can be utilized alone as a conclusive marker of neoplasia and that only their combined use can give objective information. We also reviewed the impact of this variability in the evaluation of various pathological methods to detect different stages of neoplastic transformation in the colon. It has been concluded that none of the present approaches can be absolutely conclusive and without false results, and that objective information regarding early cancerous changes may be obtained only by use of combined analyses utilizing several laboratory methods. The diagnostic procedures should be based on the complex utilization of all appropriate methods using the quantitative interpretation of the obtained data. Multivariate analysis of many parameters should be very effective for the prediction of therapeutic results.
Being Confucian: Why Confucians Needn't Be Old, Serious and Conservative (Politics of Identity – XII)
Authors: Bell Daniel A. 
Published: January 2008

AbstractIt is difficult, arguably, for modern leftist thinkers to sympathize with Confucian values that seem best suited to old, boring and deadly serious defenders of conservative traditions. But this stereotypical image may be mistaken. Drawing on his own experience, the author argues that Confucians can and should have a sense of humour and engage in social and political criticism. He also questions the idea that Confucians need to be elderly gentlemen. The article ends with some reflections on Chineseness and Confucianism.
Allergic purpura with hypoprothrombinemia
Authors: NJÅ ARNE 
Published: January 2008

SummaryA short description of the conception of disease compiled by SEIDLMAYER: »Die frühinfantile, postinfektiöse Kokarden‐Pur‐pura.« The disease occurs in infancy and childhood, up to the age of three years. Most often it is associated with catarrhal infections. It manifests itself through eruption of characteristic purpuric efflorescences, essentially localized to the extensor surfaces of the extremities, and the face, besides urticarial eruptions and a tendency to localized edemata. A case of purpura of this type is referred. Of special interest in this patient were two relations, viz.:1. An unusually strong, hemorrhagic cutaneous reaction to pneumococci, suggesting an infectious‐allergic genesis.2. A very greatly prolonged prothrombin time (more than five minutes), which could be demonstrated as long as the tendency of hemorrhage existed, and became normal at the same time as the hemorrhages ceased. The possibility of hypoprothrombinemia as a eontributary cause of the hemorrhages is discussed.
Clinical Appearance and Diagnosis of the Colon Polypus1
Authors: JOHANNES LEWIS‐ NS N. 
Published: January 2008

SummaryThe solitary pedieled colon polypus offers a complex of symptoms which will nowadays lead to a certain diagnosis, if only the possibility of this disease is borne in mind, and the investigation arranged accordingly. Rectal palpation, rectoscopy and radiological examination according to the methods given for colon polypus are the three diagnostic methods which must all be used. Three cases of colon polypus in children are reported: one with threatening bleeding and one with three polypi, one of which was diagnosed with the rectoscope and the other two by means of X‐ray.