bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polystoma australis (Monogenea): Life cycle studies in experimental and natural infections of normal and substitute hosts
Authors: Kok D. J. , Preez L. H. Du 
Published: March 2009

A South African polystome parasite found in Kassina senegalensis (Dumeril & Bibron, 1841) was thought to be different from Polystoma australis Kok & van Wyk, 1986, which occurs in K. wealii Boulenger, 1882. The successful establishment and development of parasites, following experimental cross‐infestations, indicated that both Kassina spp. are infected only by P. australis. Observations on naturally infected hosts showed a comparable prevalence of P. australis in larval populations of the two host species. Experimental cross‐infestations also led to the establishment of branchial and vesical P. australis in larval and post‐metamorphic Natalobatrachus bonebergi Hewitt & Methuen, 1913. Field observations showed the presence of branchial P. australis in tadpoles of Rana angolensis Bocage, 1866, occurring together with heavily infected K. wealii tadpoles. The findings are relevant to aspects of the taxonomy and host‐specificity of the African anuran polystomes.Summary

Polystoma australis, a parasite of Kassina wealii, was established experimentally in larval and post‐metamorphic K. senegalensis. The results indicated normal host‐parasite compatibility and it was concluded that natural infections of K. senegalensis also involve P. australis.
When tadpoles of the two host species occupied the same pools, the prevalence of P. australis in both populations was comparable. When K. senegalensis occurred alone, P. australis was absent. This gives the impression of host preference but may be due to differences in the population density of the two host species.
Data are given on the establishment, migration and mortality of branchial parasites developing towards neotenic maturity in the normal host. Migration from the left to the right branchial chamber occurs within the first eight days. Since parasite mortality is continuous, there is a great loss of reproductive potential.
Polystoma australis was established experimentally in larval and post‐metamorphic Natalobatrachus bonebergi. Rana angolensis tadpoles were found to be naturally infected with predestined bladder stages of P. australis. These findings emphasize the complexity of host‐parasite associations within the African anuran polystomes.
Elastic properties of structures in the tails of cetaceans (Phocaena and Lagenorhynchus) and their effect on the energy cost of swimming
Authors: BENNETT M. B. , KER R. F. , ALEXANDER R. MCN. 
Published: March 2009

A swimming whale must do work against hydrodynamic forces, to move its fluke through the water. In addition, it must do positive work at some stages of the swimming cycle and negative work at others, to accelerate and decelerate the fluke. The energy cost of swimming could be reduced by means of elastic elements in the tail.A mathematical model predicts the work required of the muscles, when they have elastic compliances in series with them. It is shown that there is an optimum compliance that minimizes the energy cost of swimming, for any given ratio of peak hydrodynamic force to peak inertial force.Anatomical measurements have been made on flukes, tail muscles and tendons of Phocaena and Lagenorhynchus. Mechanical tests have been made on the tendons, fluke and vertebral column. It is shown that the important compliances are those of the tendons, and the axial compliance of the vertebral column, and that these compliances should be regarded as being in series with the muscles.Calculations using these data, and Lang & Daybell's (1963) observations of a Lagenorhynchus swimming at 5 m/s, seem to show that the compliances greatly exceed the optimum value for this swimming speed. They increase the energy cost of swimming, rather than decreasing it.
Diving in darkness: whiskers as sense organs of the ringed seal (Phoca hispida saimensis)
Authors: HYVÄRINEN HEIKKI 
Published: March 2009

Underwater vocalization and the functional structure of different vibrissae of the ringed seal (Phoca hispida saimensis) of Lake Saimaa, Eastern Finland, were studied. These seals live in darkness under the ice cover for several months during the year. It is known that blind seals are managing well in the lake. Visibility under water in some parts of the area where the seals live is only 2 m. It is suggested that echolocation is used in orientation and feeding. The Saimaa seal has click and click trial underwater vocalizations. However, both the frequency and intensity of the vocalization are low compared with, for example, those of dolphins. The structural adaptations for underwater sound localization are also not well developed.The ringed seal has, however, extremely well‐developed vibrissae. The innervation of one vibrissa is more than 10 times greater than normally found in mammals. The main structural deviations from normal mammalian vibrissae are: (1) an upper cavernous sinus, (2) a groove in the wall of the capsule at the level of the lower cavernous sinus, (3) elasticity of the connective tissue bands fixing the hair root to the capsule in the lower cavernous sinus and especially (4) the structure and innervation of the ring sinus area. Sensory elements are situated upon the glassy membrane on the surface of the outer rootsheath and in the basal cell layer of the outer rootsheath which is like a sensory epithelium. Below this epithelium a layer of liquid or gelatinous material and large amounts of glycogen are found. This sensory epithelium is especially well developed in the superciliary vibrissae. These vibrissae are protruded some millimetres when the seals are attentive. It is suggested that the vibrissae also sense sounds, which are transmitted to the sensory elements by tissue conduction through the capsule wall and via the blood sinuses. The seals may possibly detect compressional waves with the vibrissae.
The anatomy of some new archaeogastropod limpets (Order Patellogastropoda, Suborder Lepetopsina) from hydrothermal vents
Authors: Fretter Vera 
Published: March 2009

The anatomy of one species of neolepetopsid limpet, Eulepetopsis vitrea (Order Patellogastropoda, Suborder Lepetopsina), is described, and this is followed by comments on differences shown by four other members of the Suborder, Neolepetopsis occulta, N. densata, N. gordensis and Paralepetopsis fioridensis.These limpets possess features linking them directly with limpets from other habitats, in this case with patellogastropods. Shared external features relate to the shallow pallial cavity with no gill; the single fold of the mantle edge, which is sensory, glandular, and has a respiratory function; in the gut the presence of inner as well as outer lips, with a strongly arched dorsal jaw associated with the former; the absence of an epipodium; and the cavity of the protoconch sealed from that of the teleoconch by a septum. The relationship displayed by internal anatomy is even more striking: the docoglossate radula and licker; the oesophageal glands forming a series of pouches, each with its own opening to the oesophagus; the stomach a simple ciliated sac lacking gastric shield, sorting area, and caecum; the enlarged initial part of the intestine; the orientation of the chambers of the heart, which is not traversed by the rectum; the lack of haemocyanin; the opening of the gonad directly to the base of the papilla of the right kidney; the absence of secondary sexual structures; the small left kidney displaying characters of a nephridial gland; and the degree of concentration of the main ganglia and the arrangement of the visceral loop. This aggregate of characters shows that the neolepetopsids cannot be separated from patellogastropods.The radula of the neolepetopsid differs from that of other patellogastropods in its unmineralized and articulating teeth and in the presence of a rachidian: the first feature appears to be a derived character and the other two ancestral. These radular differences contrast with the anatomical homogeneity exhibited not only here but throughout the patellogastropods. Such anatomical differences as do occur are most easily explained as mosaic evolution.
Studies on the thymus gland of British Cervidae, particularly muntjac, Muntiacus reevesi, and fallow, Dama dama, deer
Authors: Chapman Norma , Twigg G. I. 
Published: March 2009

The thymus in muntjac and fallow deer, as well as in sika (Cervus nippon and red (Cervus elaphus, has both cervical and thoracic portions. Foetal development of the gland in muntjac, fallow and sika is rapid and occurs relatively earlier than in the red fox, the only other mammal for which comparable data are available. Between birth and one year the thymus weights of muntjac and fallow fawns do not change significantly, but from then onwards there is a decline in weight and by six years of age the gland is very small.The thymus of muntjac appears to be less responsive to sexual changes than that of fallow and it is suggested that this may be related to the fact that muntjac breed at all times of the year. The thymus response in deer is perhaps less clear‐cut than in other mammals for which we have information and the relationship of the gland to sexual state merits further investigation.Thymus involution occurs with old age and also with trauma and many other stresses experienced by deer in the wild.
The giant squid Architeuthis in southern African waters
Authors: Roeleveld Martina A. Compagnro , Lipinski M. R. 
Published: March 2009

Three specimens of the rare giant squid (genus Architeuthis, 18 nominal species) are described from the waters around southern Africa. Consideration of their internal and external morphology, including beaks, radula, statocyst and statolith give no reason to suppose that the three specimens do not pertain to the same species. A standardized data collection form and a summary of existing morphometric data are presented for the first time and the morphology and systematics of the genus are discussed. The value of various systematic characters is examined and certain guidelines are proposed, with an appeal for a more scientific approach to Architeuthis studies.Features of the internal anatomy, including the female reproductive tract, are described and illustrated and the beak dimensions are used to evaluate existing regression formulae for beak and body parameters. The statocyst and statolith are described and illustrated in full, the statolith for the first time, and are compared with those of other squids.The value of recent data from trawl‐caught specimens, as well as indirect evidence, is cited to replace speculation in discussions on distribution and habitat. Our specimens suggest that the waters off the south‐western coast of Africa may be one of the natural habitats of Architeurhis, during both feeding and spawning periods of the life cycle.
On the interpretation of host‐parasite ecology: Heligmosomoides polygyrus (Nematoda) in wild wood mouse (Apodemus sylvaticus) populations
Authors: Gregory Richard D. 
Published: March 2009

This paper describes epidemiological and seasonal patterns in the interaction between wood mice, Apodemus sylvaticus and Heligmosomoides polygyrus. Data used in the analysis were collected by C. S. Elton and co‐workers at Bagley Wood, Oxfordshire in the late 1920s. Heligmosomoides polygyrus was by far the most common helminth parasite with 70% of all wood mice infected and average intensity around 12 worms per mouse. Male and female mice were shown to harbour similar parasite burdens. Parasite numbers per host were highly overdispersed and were well described by the negative binomial distribution. There was little evidence for convexity in age (= weight)‐intensity curves, either within or across sexes.Host and parasite numbers showed predictable seasonal patterns, with mouse populations at their largest at the end of the breeding season, in August and September, and parasite populations at their largest in the late spring, around May. Results are discussed in relation to the ecology of H. polygyrus in wood and laboratory mice, and tentative comparison is made with human helminth infection. The interpretation of epidemiological patterns in these data was problematic. Of particular importance was the statistical distribution of parasites within the host population, and possible differences between mouse sexes in relation to growth, survival and trapping. Such difficulties are relevant to a range of similar field data.
Reproductive biology and population dynamics of an ovoviviparous land snail, Lauria cylindracea (Pupillidae)
Authors: Heller J. , Sivan N. , Hodgson A. N. 
Published: March 2009

The orthurethran land snail Lauria cylindracea is ovoviviparous. We examined its life history in Israel, where it lives in litter of the riparian forest floor, in a cool, humid habitat, that has a very stable and predictable temperature. Activity of snails started in winter and continued well into summer with gametogenesis commencing in early winter, after the beginning of the rainy season. In mid winter, all animals showed advanced spermatogenesis, early oogenesis, vitellogenic eggs and a few of the adults contained embryos. By spring and early summer, the gonads were larger, with both mature sperm and up to seven vitellogenic eggs; and up to 100% of the adults contained embryos, usually four per individual. A reproductive adult weighed about 4.5 mg, of which 17–25% was embryo weight. In later summer and autumn, we observed no feeding or reproductive activity, no gametogenesis, and very few embryos.We distinguished three age groups: juveniles, subadults and adults. Juveniles were born in summer by adults having enough moisture to be active, whereas adults on dry leaves appeared to retain their embryos. The number of juveniles was therefore never as high as could be expected from the number of embryos inside the animals, and never exceeded 26% of the population. The juveniles grew until spring and then, as subadults, stopped growth until the following winter. It took a snail two winters to reach reproductive maturity, and the lifespan was about five years. About 30% of the adult snails died in late summer. All individuals throughout the year were euphallic, which is in contrast to the high frequency of aphally in other pupilloideans.In discussing the adaptive significance of ovoviviparity in Lauria, we note that it is a minute snail, and therefore constrained to low fecundity—it can produce only few ova per unit time. Under such conditions, ovoviviparity may be advantageous in that the (few) hatchlings can immediately feed and grow, fight off fungi, cope with brief periods of desiccation and avoid drowning or flooding. In environments subject to frequent flooding, eggs may be retained within the adult until full embryonic development of the kidney. In such an environment of excess water, ovoviviparity may be advantageous.
Father and son sugar gliders: more than a genetic coalition?
Authors: Klettenheimer B. S. , Temple‐Smith P. D. , Sofronidis G. 
Published: March 2009

Co‐operation between two or more individuals has been shown to yield benefits in some vertebrate species (Bygott, Bertram & Hanby, 1979; Packer & Pusey, 1982; Grinnell, Packer & Pusey, 1995), however, until now such behaviour has not been described for marsupials. In this two‐and‐a‐half‐year study co‐operative behaviour among male sugar gliders (Petaurus breviceps) was revealed. A dominant relationship to females was not observed.Male sugar gliders not only showed extensive co‐operative behaviour in suppressing subordinate males, but in sharing food and nesting boxes as well as taking care of the offspring. DNA fingerprinting has been used to describe the genetic variability in relatedness of the coalition partners.Co‐operative behaviour in male sugar gliders was exclusively observed among closely related individuals, therefore supporting the kin‐selection theory in this small marsupial.We describe the genetic variability in relatedness, the behaviour and some physiological parameters of male sugar gliders in four captive groups to test the hypothesis that the sugar glider is an example of co‐operative behaviour involving kin selection in marsupials
Crustacean symbionts of the sea anemone Telmatactis cricoides at Madeira and the Canary Islands*
Authors: Wirtz Peter 
Published: March 2009

The crustacean symbionts of the club‐tipped sea anemone Telmatactis cricoides (Duchassaing, 1850) were studied at Madeira (n= 81 anemones) and the Canary Islands (n= 124 anemones).Of all anemones, 86% had crustacean symbionts. Nineteen species of crustaceans were encountered in association with Telmatactis cricoides. There were up to 18 individuals of up to four crustacean species associated with the same anemone. Anemone size and number of crustacean symbionts were positively correlated (P < 0.001) but only weakly so (r=+0.27). The most common crustacean symbiont was the shrimp Thor amboinensis, encountered with 65% of all anemones.Frequency and type of association with Telmatactis cricoides is described for each of the crustacean symbionts, Thor amboinensis, Lysmata grabhami, Lysmata seticaudata, Eualus occultus, Brachycarpus biunguiculatus, Stenorhynchus lanceolatus, Homola barbata, Pilumnus villosissimus, Gnathophyllum elegans, Inachus phalangium, Heteromysis sp. nuv., Palaemonella atlantica, Herbstia condyliata, Stenopus spinosus, Athanas nitescens, Dromia personata Xantho incisus, Galathea sp., Liocarcinus sp.The shrimp Lysmata grabhami appears to live in stable pairs of two simultaneous hermaphrodites, a social structure not previously described for any crustacean species.
Gender‐ and age‐related benefit of renal replacement therapy on health‐related quality of life
Authors: Kontodimopoulos Nick , Pappa Evelina , Niakas Dimitris 
Published: March 2009

Objectives:  The aim of this study was to compare the health‐related quality of life (HRQOL) of end‐stage renal disease patients on renal replacement therapy with that of subjects of the same gender and similar age from the general population, in an attempt to determine patient subgroup that benefits more from the treatment.Methods:  A cross‐sectional study involving haemodialysis, peritoneal dialysis and renal transplant patients (n = 874) was conducted with subjects providing socio‐demographic and disease‐related data, and completing the validated Greek Short Form‐36 (SF‐36) Health Survey. Patient‐specific z‐scores were calculated using mean SF‐36 scores and SD of age‐ and gender‐matched subgroups from the Greek norms.Results:  Males and younger patients generally reported better HRQOL. However, z‐scores in these groups generally showed a larger health deficit, i.e. an increased divergence from the HRQOL of their age‐ and gender‐matched counterparts of the general population, compared with the health deficit observed in female and younger patients.Conclusions:  Health‐related quality of life studies involving disease groups may sometimes be inconclusive if results are not compared with population norms, and particularly with subgroups matched for important demographic variables. Otherwise, as this study has shown, it is possible that important information may remain unrevealed.
How news content influences anti‐immigration attitudes: Germany, 1993–2005
Authors: BOOMGAARDEN HAJO G. , VLIEGENTHART RENS 
Published: March 2009

AbstractImmigration is an increasingly important political issue in Western democracies and a crucial question relates to the antecedents of public attitudes towards immigrants. It is generally acknowledged that information relayed through the mass media plays a role in the formation of anti‐immigration attitudes. This study considers whether news coverage of immigrants and immigration issues relates to macro‐level dynamics of anti‐immigration attitudes. It further explores whether this relationship depends on variation in relevant real world contexts. The models simultaneously control for the effects of established contextual explanatory variables. Drawing on German monthly time‐series data and on ARIMA time‐series modeling techniques, it is shown that both the frequency and the tone of coverage of immigrant actors in the news significantly influence dynamics in anti‐immigration attitudes. The strength of the effect of the news, however, depends on contextual variation in immigration levels and the number of asylum seekers. Implications of these findings are discussed in the light of the increasing success of extreme right parties and growing opposition to further European integration.
The more, the better? Counterfactual evidence on the effect of compulsory voting on the consistency of party choice
Authors: SELB PETER , LACHAT ROMAIN 
Published: March 2009

AbstractCompulsory voting (CV) undoubtedly raises electoral turnout. Yet does it also affect individual party choices and aggregate election outcomes? Previous studies have focused on partisan or ‘directional’ effects of CV in favour of, for example, social‐democratic or anti‐establishment parties. These effects are usually small, however. Using survey data from the Belgian General Elections Study, this article finds that CV primarily affects the consistency, rather than the direction, of party choices. In particular, the analyses suggest that CV compels a substantial share of uninterested and less knowledgeable voters to the polls. These voters, in turn, cast votes that are clearly less consistent with their own political preferences than those of the more informed and motivated voluntary voters. Claims that CV promotes equal representation of political interests are therefore questionable.
Aβ aggregation and possible implications in Alzheimer's disease pathogenesis
Authors: Bharadwaj Prashant R. , Dubey Ashok K. , Masters Colin L. , Martins Ralph N. , Macreadie Ian G. 
Published: March 2009

Introduction
Amyloid Structure
Mechanism of Amyloid aggregation
Aβ: a natively unfolded protein?
Ambiguities in synthetic Ab studies
Formation of Amyloid plaques
Role of Ab in AD Pathogenesis
Conclusion

AbstractAmyloid β protein (Aβ) has been associated with Alzheimer's disease (AD) because it is a major component of the extracellular plaque found in AD brains. Increased Aβ levels correlate with the cognitive decline observed in AD. Sporadic AD cases are thought to be chiefly associated with lack of Aβ clearance from the brain, unlike familial AD which shows increased Aβ production. Aβ aggregation leading to deposition is an essential event in AD. However, the factors involved in Aβ aggregation and accumulation in sporadic AD have not been completely characterized. This review summarizes studies that have examined the factors that affect Aβ aggregation and toxicity. By necessity these are studies that are performed with recombinant‐derived or chemically synthesized Aβ. The studies therefore are not done in animals but in cell culture, which includes neuronal cells, other mammalian cells and, in some cases, non‐mammalian cells that also appear susceptible to Aβ toxicity. An understanding of Aβ oligomerization may lead to better strategies to prevent AD.