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  • 1
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. In Bere Stream three species of adult simuliids, S. ornatum, S. equinum and S. angustipes were parasitized by Sperchon setiger larvae. Trapped adult S. ornatum were more often parasitized than corresponding adults of S. equinum. The lower 95% confidence limits were used as an indication of the relative importance of the statistically significant differences and were high (10.4–33.6%). Laboratory experiments on the occupation of host pupae by pre-parasitic Sperchon setiger larvae also indicated that pupae of S. ornatum were more often occupied than S. equinum. This was confirmed by tests on the difference in percentage occupation of more than 4000 held-collected host pupae. In tests that indicated a significant difference in percentage parasitization between the sexes of the three host species, females were more often parasitized. However, the lower 95% confidence limits for the increase in percentage parasitization of females compared to males were low (0.9–10.2%). The majority of adult simuliids carried only one parasite. The mean number of larvae per trapped parasitized host was significantly greater for S. ornatum (2.69) than for S. equinum (1.77). There was no significant difference between the mean number of parasites carried by the sexes of S. ornatum for each year from 1975 through 1978 but females were significantly more heavily parasitized than males during 1979. The ventral neck region of all three host species is the main attachment site for Sperchon setiger larvae.The morphology of the pupae of S. ornatum and S. equinum is related to differences in levels of percentage parasitization between these two species. It is suggested that pupal morphology may be the most important factor in the selection of host simuliids by Sperchon setiger larvae.
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 1 (1971), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Astrophysics and space science 224 (1995), S. 395-398 
    ISSN: 1572-946X
    Keywords: Stars: Circumstellar matter ; Stars:Individual (β Pictoris)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The asymmetries in the brightness structure and levels of polarization between the two sides of theβ Pic disc are discussed. The possibility of these differences being caused by a planet, or planets, within the circumstellar disc is investigated.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 15 (1960), S. 179-188 
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Schlüpfende Imagines wurden in einem etwa 600 m über dem Meeresspiegel liegenden Bach und in einem zweiten, niedrigeren Bach gefangen. Der Maximum-Temperaturwert war um 5° C höher in dem niedrigeren Bach. Nur in dem höheren Bach kamen Ameletus inopinatus, Baetis tenax, Diura bicaudata und Capnia vidua vor. Die Arten, die lediglich in dem niedrigeren Bach gefunden wurden, sind ebenfalls erörtert. Im niedrigeren Bach fand der erstmalige Imagines-Auftritt früher statt and die Flugzeit war kürzer. In den Gattungen Protonemura and Leuctra folgte eine Reihe von Arten nacheinander, aber die späteste der emen and die früheste der nächsten erschienen zusammen.
    Notes: Summary 1. The captures from emergence traps in a high mountain stream, Whelpside Ghyll, are compared with those from similar traps in a warmer lower stream, Ford Wood Beck. 2. The number of species caught by the Ford Wood Beck traps and the number of species known to inhabit the stream are discussed. 3. In Whelpside Ghyll the traps yielded 4 species of Ephemeroptera, 12 of Plecoptera and 7 of Trichoptera, in Ford Wood Beck, 6 species of Ephemeroptera, 8 of Plecoptera and 7 of Trichoptera. 4. Leuctra hippopus, L. inermis, Chloroperla torrentium, Isoperla grammatica, Bäetis rhodani, B. pumilus and Philopotamus montanus were caught from both streams. 5. Species found in Whelpside Ghyll and not in Ford Wood Beck are Ameletus inopinatus, Bäetis tenax, Protonemura montana, Diura bicaudata and Capnia vidua, of which two are known high-altitude species and one, possibly two, is known also from stony lake shores being kept out of other habitats presumably by competition. 6. The proportion of Bäetids to Ecdyonurids and Ephemerellids is higher in the Whelpside Ghyll station than in streams at lower altitudes. 7. There was, in both streams, a succession of Protonemura and Leuctra species but the Leuctra species, except L. fusca, were not isolated in time. 8. The distribution of the sexes during the emergence period of 6 species of Plecoptera is shown. 9. There was a considerable difference in the emergence period from the two streams of Leuctra hippopus, L. inermis and Chloroperla torrentium, the emergence period in Ford Wood Beck being earlier and shorter than in Whelpside Ghyll. 10. Leuctra inermis has emerged from Ford Wood Beck during six successive years in May and June with only about 14 days difference between first emergers, and Chloroperla torrentium, emerging during May, June and July, has had only about 19 days difference between first emergers during that time.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 14 (1959), S. 85-90 
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Flugperiode von Ameletus inopinatus dauert von Ende Mai bis Ende August. Dass das Schlüpfen aus dem Ei von September bis Februar stattfindet, wird aus dem Fang von winzigen Nymphen während dieser Monate geschlossen. Die Beurteilung der Zahlen der verschiedenen Grossengruppen zeigt ein Maximum des Schlüpfens aus dem Ei im Herbst und ein zweites früh im folgenden Jahr. In der Periode zwischen diesen beiden Maxima schlüpfen wenig oder keine Tiere. Nymphen, die während des ganzen Winters wachsen, liefern die grösseren Imagines im Mai und Anfang Juni. Es wird angenommen, dass alle kleineren Imagines, die später schlüpfen, aus Eiern stammen, die später geschlüpft sind. Der Lebenszyklus in einem Jahr vollendet.
    Notes: Summary Ameletus inopinatus has an emergence period lasting from late May until late August. That the hatching of eggs goes on from September to February is deduced from the capture of tiny nymphs in these months. Judging from the numbers in the different size groups, there is a peak of egg hatching in the autumn and another early the following year with a period in between with little or none. Nymphs growing throughout the winter produce the larger adults in May and early June, and it is thought that all the smaller adults emerging later originated from eggs that hatched later. The life cycle is completed in a year.
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  • 6
    Publication Date: 1967-07-03
    Print ISSN: 0031-9007
    Electronic ISSN: 1079-7114
    Topics: Physics
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  • 7
    Publication Date: 2015-10-16
    Description: We present the extended source catalogue for the UKIRT Wide Field Infrared Survey for H 2 (UWISH2). The survey is unbiased along the inner Galactic Plane from $l \approx 357\deg$ to $l \approx 65\deg$ and | b | ≤ 1 $_{.}^{\circ}$ 5 and covers 209 deg 2 . A further 42.0 and 35.5 deg 2 of high dust column density regions have been targeted in Cygnus and Auriga. We have identified 33 200 individual extended H 2  features. They have been classified to be associated with about 700 groups of jets and outflows, 284 individual (candidate) planetary nebulae, 30 supernova remnants and about 1300 photodissociation regions. We find a clear decline of star formation activity (traced by H 2  emission from jets and photodissociation regions) with increasing distance from the Galactic Centre. About 60 per cent of the detected candidate planetary nebulae have no known counterpart and 25 per cent of all supernova remnants have detectable H 2  emission associated with them.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 8
    Publication Date: 2014-12-21
    Description: We present 2–2.4 μm integral field spectroscopy of a sample of hot post-asymptotic giant branch stars with early-B spectral types, using the Near-infrared Integral Field Spectrometer instrument on Gemini North. These stars are just beginning to ionize their immediate environments and turn into planetary nebulae (PNe). We use molecular hydrogen emission lines together with hydrogen and helium recombination lines to explore the distribution of molecular and atomic gas and the extent of the developing ionized region. We see a range of evolutionary stages: IRAS 18062+2410 and IRAS 18379–1707 have recently developed compact and unresolved regions of photoionized H within axisymmetric molecular envelopes, with the former object increasing its Br flux by a factor of 5.3 in 14 years; IRAS 22023+5249 and IRAS 20462+3416 have extended Br nebulae and in the latter object only weak H 2 emission remains; IRAS 19336–0400 is at a more advanced stage of PN formation where H 2 is mostly dissociated and we see structure in both the H and He recombination line nebulae. IRAS 19200+3457 is the only object not to show the He i line at 2.058 μm and is probably the least evolved object in our sample; the H 2 emission forms a ring around the star and we suggest that this object may be a rare example of a ‘round’ pre-PN in transition to a ‘round’ PN.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 9
    Publication Date: 2014-12-29
    Description: We present 2–2.4 μm integral field spectroscopy of a sample of hot post-asymptotic giant branch stars with early-B spectral types, using the Near-infrared Integral Field Spectrometer instrument on Gemini North. These stars are just beginning to ionize their immediate environments and turn into planetary nebulae (PNe). We use molecular hydrogen emission lines together with hydrogen and helium recombination lines to explore the distribution of molecular and atomic gas and the extent of the developing ionized region. We see a range of evolutionary stages: IRAS 18062+2410 and IRAS 18379–1707 have recently developed compact and unresolved regions of photoionized H within axisymmetric molecular envelopes, with the former object increasing its Br flux by a factor of 5.3 in 14 years; IRAS 22023+5249 and IRAS 20462+3416 have extended Br nebulae and in the latter object only weak H 2 emission remains; IRAS 19336–0400 is at a more advanced stage of PN formation where H 2 is mostly dissociated and we see structure in both the H and He recombination line nebulae. IRAS 19200+3457 is the only object not to show the He i line at 2.058 μm and is probably the least evolved object in our sample; the H 2 emission forms a ring around the star and we suggest that this object may be a rare example of a ‘round’ pre-PN in transition to a ‘round’ PN.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 10
    Publication Date: 2016-12-22
    Description: We present the discovery of 816 high-amplitude infrared variable stars ( K s  〉 1 mag) in 119 deg 2 of the Galactic mid-plane covered by the VISTA Variables in the Via Lactea (VVV) survey. Almost all are new discoveries and about 50 per cent are young stellar objects (YSOs). This provides further evidence that YSOs are the commonest high-amplitude infrared variable stars in the Galactic plane. In the 2010–2014 time series of likely YSOs, we find that the amplitude of variability increases towards younger evolutionary classes (class I and flat-spectrum sources) except on short time-scales (〈25 d) where this trend is reversed. Dividing the likely YSOs by light-curve morphology, we find 106 with eruptive light curves, 45 dippers, 39 faders, 24 eclipsing binaries, 65 long-term periodic variables ( P 〉 100 d) and 162 short-term variables. Eruptive YSOs and faders tend to have the highest amplitudes and eruptive systems have the reddest spectral energy distribution (SEDs). Follow-up spectroscopy in a companion paper verifies high accretion rates in the eruptive systems. Variable extinction is disfavoured by the two epochs of colour data. These discoveries increase the number of eruptive variable YSOs by a factor of at least 5, most being at earlier stages of evolution than the known FUor and EXor types. We find that eruptive variability is at least an order of magnitude more common in class I YSOs than class II YSOs. Typical outburst durations are 1–4 yr, between those of EXors and FUors. They occur in 3–6 per cent of class I YSOs over a 4 yr time span.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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