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  • 1
    Digitale Medien
    Digitale Medien
    Water relations and desiccation-avoiding behavior in the vinegaroon Mastigoproctus giganteus (Arachnida: Uropygi) (1971)
    Springer
    Entomologia experimentalis et applicata 14 (1971), S. 99-106 
    Details
    ISSN: 1570-7458
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Mastigoproctus giganteus se rencontre dans les régions arides du Sud-Ouest des U.S.A.; rare pendant la saison sèche, il appraît après les pluies. C'est un prédateur nocturne. principalement d'insectes. Le présent travail tente de préciser comment cet Arachnide réagit aux conditions d'aridité des régions désertiques. De grands exemplaires vivants de M. giganteus montrent un taux de perte en eau relativement élevé pour une température de 26° avec une humidité relative pouvant aller jusqu'à 95%. Pour ces grands spécimens la transpiration à travers la cuticule s'accroît de façon approximativement linéaire pour les températures supérieures, ce qui indique l'absence probable d'une couche cireuse épicuticulaire fonctionnelle. Des animaux hydratés ne répondent pas à un gradient d'humidité, mais après avoir été soumis à des conditions de dessication les individus de petite taille montrent une préférence marquée pour l'air le plus humide. Ils ne manifestent aucune préférence entre la lumière (1,500 lux) ou l'obscurité lorsqu'ils sont placés sur sable sec ou humide, même après avoir une dessication partielle. La faible aptitude physiologique de ces animaux pour réduire leurs pertes en eau semble compensée par un sens thigmotactique hautement développé qui leur permet d'une part, de capturer aisément leurs proies, d'autre part de détecter des surfaces non-horizontales contre lesquelles ils creusent alors si le substrat est humide. Ce comportement doit jouer un rôle important en évitant à l'animal les conditions de dessication.
    Notizen: Abstract The vinegaroon or whip scorpion Mastigoproctus giganteus gains water by drinking from a moist substrate and from its prey. These are found by the sensitive antenniform front legs. Large specimens readily lose water to the air at 26° at humidities up to 95% R.H. As temperatures increase they lose water in proportion to the saturation deficit of the atmosphere, suggesting the absence of an epicuticular wax layer. Desiccated vinegaroons respond positively to moist air in a humidity gradient, but show no preference between darkness and light. Substrate moisture does not affect the lack of such a preference by normal animals. Burrowing is characteristic of dehydrated individuals. By using their sensitive front legs these first detect nonhorizontal surfaces and, provided the substrate is moist, dig burrows against — and in nature most likely beneath — such surfaces so that further water loss is presumably avoided.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00341130
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Water and temperature relations, and diurnal rhythms of scolopendromorph centipedes (1970)
    Springer
    Entomologia experimentalis et applicata 13 (1970), S. 187-193 
    Details
    ISSN: 1570-7458
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les Myriapodes étudiés montrent une perte d'eau par évaporation lorsqu'ils sont placés dans une ambiance à 27° et dont l'humidité relative est de 98%; il n'y a aucune indication permettant de penser que ces arthropodes peuvent se rehydrater à partir des surfaces mouillées ou de l'humidité atmosphérique, par prélèvement à travers leur tégument. La perte d'eau par transpiration est directement en rapport avec la déficience de saturation de l'air et il n'y a aucune température critique de transition pour laquelle la cuticule deviendrait perméable à l'eau. Néanmoins l'eau est retenue plus efficacement par Scolopendra que par Lithobius, ce qui suggère chez le premier genre une adaptation aux milieux chauds et secs. Le point de surfusion mesuré pour de grands spécimens maintenus en insectarium, est en moyenne de -3,1±0.48° et un seul choc à cette température de surfusion peut être préjudiciable ou même fatal. Cela indique que ces arthropodes doivent éviter les froids de l'hiver en creusant plus profondément les galeries. Des expériences utilisant un actographe montrent que ces Myriapodes ont une activité nocturne. Le rythme naturel d'activité persiste à l'obscurité et à une température constante, mais il est rapidement perdu par exposition à un éclairement continu.
    Notizen: Abstract Water is lost by transpiration at relative humidities (R.H.) as high as 98% at 27° C and there is no evidence of the uptake of moisture through the integument from unsaturated air or moist surfaces. Water-loss through transpiration is directly related to saturation deficiency and there is no ‘critical’ transitional temperature at which the cuticle becomes porous. Nevertheless, water is retained more efficiently in Scolopendra than it is in Lithobius, suggesting an adaptation to hot-dry environments. The mean supercooling point of large specimens conditioned in an insectary is -3.1±0.48° and a single supercooling can be injurious or fatal. This indicates that cold winter weather must be avoided by burrowing deeply. Aktograph experiments show that these centipedes are nocturnal. The rhythm persists in darkness at constant temperature, but is quickly lost in constant light.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00344460
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  • 3
    Digitale Medien
    Digitale Medien
    Double clusters and gravitational lenses (1986)
    [s.l.] : Nature Publishing Group
    Nature 323 (1986), S. 514-515 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] We have used two approximate methods to estimate the number of wide double images. The first works from the number density of rich clusters12 and the clustering of clusters3. There is no strong richness/velocity dispersion relation13'14 but we shall assume that two clusters of Abell richness class ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/323514a0
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  • 4
    Digitale Medien
    Digitale Medien
    Food, ingestion rates, and assimilation in the desert millipede Orthoporus ornatus (Girard) (Diplopoda) (1975)
    Springer
    Oecologia 20 (1975), S. 231-236 
    Details
    ISSN: 1432-1939
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Orthoporus ornatus feeds mostly on dead plant material and on superficia tissue of desert shrubs. Sand, small particles of rock, and parts of arthropods are also ingested. Millipedes could not be induced to feed in the absence of moist soil in the laboratory after an initial day of feeding. Field observations of apparent food preferences were made at several sites in the southwestern U.S. Millipedes at Big Bend National Park, Texas, fed regularly on bark of the following desert shrubs: cholla (Opuntia sp.), cresotebush (Larrea divaricata), and ocotillo (Fouqueria splendens). Millipedes on the West Mesa of Albuquerque, New Mexico, fed mostly on superficial tissues of dead Russian-thistle (Salsola kali). At the Jornada Validation Site, Dona Ana County, New Mexico, millipedes fed regularly on the bark of Mormon tea (two Ephedra spp.) and mesquite (Prosopis glandulosa). Otherwise, grazing on an assortment of surface litter was commonly observed. Ingestion rates and assimilation efficiencies were determined in the laboratory for millipedes feeding on Prosopis and Ephedra using an ash-free technique. Assimilation efficiencies and ingestion rates were temperature dependent, increasing with a rise in temperature. Ingestion rates for Ephedra ranged from 0.020 to 0.050 g ash-free dry wt per g dry wt tissue per day, with assimilation efficiencies ranging from 20–37%. Ingestion rates were lower for Prosopis than for Ephedra. Feeding experiments at 24° C were considered to depict feeding characteristics found in surface millipedes under field conditions. These millipedes ingested 0.034 g ash-free dry weight of Ephedra per g dry body weight per day with 31.4% of the food being assimilated. No significant differences occurred between assimilation efficiencies calculated by ash-free techniques and by using caloric values of food and feces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00347475
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  • 5
    Digitale Medien
    Digitale Medien
    Feeding-season production in the desert millipede Orthoporus ornatus (Girard) (Diplopoda) (1976)
    Springer
    Oecologia 24 (1976), S. 265-276 
    Details
    ISSN: 1432-1939
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Production during an assumed 131-day feeding season in 1974 was estimated for Orthoporus ornatus between 4.0 and 12.0 mm in midsegment width at Tornillo Flat, Big Bend National Park, Texas. A conservative density estimate in 1973 of 1,302 millipedes ha-1 involved daily specimen removal from three, 929-m2 plots for a month. Each plot typified a different aspect of local desert vegetation; most specimens came from the plot with greatest plant diversity and relatively high (20%) cover. Production calculations using 1973 density estimates were based on increase in size-class specific dry weight (minus gut contents) between 14 May and 21 September, 1974. Production ha-1 of cuticle and tissue was estimated at 0.85 kg (1972 kcal), while that of tissue alone came to 0.29 kg (1971 kcal). Orthoporus ornatus from Albuquerque, New Mexico increased in dry weight during 92 days in 1974 more rapidly and to a greater extent than comparable size classes at Tornillo Flat. An estimated feeding-season energy budget based on ash-free values of shrub food eaten at Tornillo Flat indicated ingestion ha-1 of 3,434 g (13,712 kcal) and defecation of 3,181 g (9,187 kcal). An independent estimate of ingestion based on known ingestion rates was 8,851 g ha-1. Considering probable net primary production at Tornillo Flat, local O. ornatus exert a trophic impact similar to that of other large invertebrate detritivores elsewhere.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00345478
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  • 6
    Digitale Medien
    Digitale Medien
    Respiratory metabolism of the desert millipede Orthoporus ornatus (Girard) (Diplopoda) (1974)
    Springer
    Oecologia 17 (1974), S. 179-186 
    Details
    ISSN: 1432-1939
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Respiratory metabolism was measured each month for Orthoporus ornatus throughout a year. Respiratory rates were determined at a standard 20°C and at the mean ambient soil temperature at time of collection. No significant differences were noted between respiratory rates of reproductively mature males and females. A size relationship between live body weight and oxygen consumption per unit weight was found. The b values for 20°C and 25°C were-0.28 and-0.24, respectively. Premolt specimens had lower respiratory rates than postmolt individuals. There were significant differences between Q 10 values of animals exposed to temperatures above and below ambient field conditions. Seasonal changes in the use of metabolic reserves by O. ornatus were indicated by corresponding changes in RQ values. A “best estimate” of annual respiratory metabolism was 1332 cal g-1yr-1. Respiratory metabolism closely paralleled changes in ambient field temperature and was at its peak in July when animals were on the soil surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00346280
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  • 7
    Digitale Medien
    Digitale Medien
    Patterns of hemolymph osmoregulation in three desert arthropods (1976)
    Springer
    Journal of comparative physiology 112 (1976), S. 295-305 
    Details
    ISSN: 1432-136X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Hemolymph osmoregulation was examined in three species of desert arthropods: a tenebrionid beetle,Eleodes hispilabris, a vejovid scorpion,Paruroctonus aquilonalis, and a spirostreptid millipede,Orthoporus ornatus. During desiccation, beetles regulated hemolymph osmolality and scorpions tolerated increasing osmolality. Millipedes displayed both osmotic regulation and tolerance patterns depending on sex and on duration of desiccation. Rehydration after desiccation depressed blood osmolality of male scorpions and beetles below levels found for freshly collected specimens. This was not the case in millipedes. Seasonal osmolality changes were studied and recorded among field-collected scorpions and beetles. Patterns of regulation and tolerance of hemolymph osmolality appear to vary among different kinds of desert arthropods.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00692300
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  • 8
    Digitale Medien
    Digitale Medien
    Anatomy and histology of the alimentary tract of the desert millipede Orthoporus ornatus (Girard) (Diplopoda: Spirostreptidae) (1977)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 151 (1977), S. 121-130 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The alimentary tract of the desert millipede Orthoporus ornatus is essentially a straight tube consisting of a histologically distinct foregut, midgut, pylorus, hindgut, and rectum. Common to each region, but often different in regional appearance, are an outer sheath layer, longitudinal and circular muscle layers, a basement membrane, and an inner epithelial layer. Foregut and midgut lumina are lined by a cuticular intima, while a peritrophic membrane occurs in the midgut lumen.Gut structure is considered in the context of the known feeding habits and digestive efficiency of this long-lived, seasonally restricted detritivore.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051510107
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  • 9
    facet.materialart.
    Unbekannt
    HST imaging of the dusty filaments and nucleus swirl in NGC4696 at the centre of the Centaurus Cluster (2016)
    Oxford University Press
    Details
    Publikationsdatum: 2016-07-02
    Beschreibung: Narrow-band HST imaging has resolved the detailed internal structure of the 10 kpc diameter H α+[N  ii ] emission line nebulosity in NGC4696, the central galaxy in the nearby Centaurus cluster, showing that the dusty, molecular, filaments have a width of about 60 pc. Optical morphology and velocity measurements indicate that the filaments are dragged out by the bubbling action of the radio source as part of the active galactic nucleus feedback cycle. Using the drag force we find that the magnetic field in the filaments is in approximate pressure equipartition with the hot gas. The filamentary nature of the cold gas continues inwards, swirling around and within the Bondi accretion radius of the central black hole, revealing the magnetic nature of the gas flows in massive elliptical galaxies. HST imaging resolves the magnetic, dusty, molecular filaments at the centre of the Centaurus cluster to a swirl around and within the Bondi radius.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
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    Optical emission line nebulae in galaxy cluster cores 1: the morphological, kinematic and spectral properties of the sample (2016)
    Oxford University Press
    Details
    Publikationsdatum: 2016-06-09
    Beschreibung: We present an Integral Field Unit survey of 73 galaxy clusters and groups with the VIsible Multi Object Spectrograph on the Very Large Telescope. We exploit the data to determine the H α gas dynamics on kpc scales to study the feedback processes occurring within the dense cluster cores. We determine the kinematic state of the ionized gas and show that the majority of systems (~2/3) have relatively ordered velocity fields on kpc scales that are similar to the kinematics of rotating discs and are decoupled from the stellar kinematics of the brightest cluster galaxy. The majority of the H α flux (〉50 per cent) is typically associated with these ordered kinematics and most systems show relatively simple morphologies suggesting they have not been disturbed by a recent merger or interaction. Approximately 20 per cent of the sample (13/73) have disturbed morphologies which can typically be attributed to active galactic nuclei activity disrupting the gas. Only one system shows any evidence of an interaction with another cluster member. A spectral analysis of the gas suggests that the ionization of the gas within cluster cores is dominated by non-stellar processes, possibly originating from the intracluster medium itself.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
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