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  • 1
    Publication Date: 2021-10-07
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev , info:eu-repo/semantics/article
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 76 (1981), S. 69-79 
    ISSN: 1573-5117
    Keywords: Physicochemical ; fecal bacteria ; benthic macroinvertebrates ; diversity ; similarity ; discharge
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Water quality of Menard Creek in the Big Thicket National Preserve of southeast Texas was studied from July 1978 to June, 1979 utilizing physicochemical parameters, bacteriological data, and benthic macroinvertebrates. Physicochemical conditions generally indicated good water quality. Dissolved oxygen concentrations were always high and all other parameters were within the expected ranges for small streams in this area. Conductivity and chlorides indicated low concentrations of oil field brines at Stations 4 and 5. Numbers of fecal bacteria were higher than acceptable at all stations during much of the study period. Highest numbers were generally found after heavy rains and surface runoff. Fecal coliform to fecal streptococci ratios indicated human contamination in 53 percent of the 60 samples, while non-human contamination was found in 12 percent of the samples. 125 taxa and 7,462 individuals of benthic macroinvertebrates were collected. Chironomids (44.8%, 38 sp.) and oligochaetes (32.1%, 13 sp.) were the dominant groups. The oligochaete Aulodrilus pigueti and the trichopterans Lype diversa and Brachycentrus numerosus were reported in Texas for the first time. The greatest number of taxa was found at Station 1 (79), while Station 5 had the fewest (61). Station 1 had the highest annual species diversity ({xxd}) of 4.37. The other stations had intermediate to high values indicating moderately stressed conditions during high discharge. Sørenson's (1948) index of similarity showed relatively high coefficients of faunal similarity between stations, depending on discharge.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-5117
    Keywords: Benthic macroinvertebrates ; reservoir ; colonization ; succession ; freshwater ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Colonization and succession of benthic macroinvertebrates in Arcadia Lake, an urban reservoir, were studied for four years. Physicochemical conditions including water temperature, dissolved oxygen concentrations, pH, specific conductance, and Secchi disc depth were also recorded. Colonization of the reservoir occured fairly rapidly through a sequence of three invasions. The first, and most significant, colonists were primarily facultative species already present in streams and ponds that were inundated by the impoundment. Later arrivals tended to be limnophilic species that probably came from other bodies of water. Of 30 species encountered in a pre-impoundment collection, only six were still present three years following impoundment. Thirty-three additional benthic macroinvertebrates species invaded the area following impoundment. Dominant taxa in the reservoir included Dero nivea, Limnodrilus sp., Chaoborus punctipennis, Chironomus sp., and Procladius sp. Pollutants accumulating in this urban reservoir, including metals and pesticides, and siltation probably have kept benthic populations relatively low and possibly reduced potential species diversity.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 108 (1984), S. 181-185 
    ISSN: 1573-5117
    Keywords: Chaoborus ; temporary pools ; migration ; evolution ; adaptive zone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A diurnal vertical migration of larvae of Chaoborus punctipennis (Say) was observed in shallow temporary woodland pools in East Texas. In the laboratory, in 153 cm tall columns, the larvae underwent a much greater migration than possible in the shallow pools. We hypothesize that the migratory behavior and transparent body of Chaoborus larvae may have originally evolved in such shallow water habitats. These traits enabled Chaoborus to successfully invade the quite different adaptive zone of predation in the plankton of deep lakes.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 135 (1986), S. 271-285 
    ISSN: 1573-5117
    Keywords: Chironomidae ; aquatic insects ; benthos ; stream ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Eighty-seven species of chironomid larvae were collected from streams in the Big Thicket area of southeast Texas. Samples of leaf debris, wood debris, and sand were taken from the streams and the larvae occupying the substrates were analyzed. Four subfamilies were represented including Tanypodinae (12 species), Diamesinae (2 species), Orthocladiinae (30 species), and Chironominae (43 species). Dominant species included Lopescladius sp., Polypedilum ? convictum, Polypedilum ? halterale, Cladotanytarsus sp. group A, Rheotanytarsus sp., and Tanytarsus sp. 2. A brief account of the habitat and the distribution of each species encountered during this study is given.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 134 (1986), S. 29-41 
    ISSN: 1573-5117
    Keywords: Chironomidae ; stream ecology ; benthos ; sampling ; diversity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chironomid larvae were collected from streams in the Big Thicket area of East Texas from November, 1981 to October, 1982. Primary stations were sampled monthly and secondary stations bi-annually. Samples of leaf debris, wood debris, and sand were taken from each station and the chironomid larvae occupying the substrates were analyzed. A total of 15 112 individuals including 87 species were collected. Four subfamilies of Chironomidae were represented: Tanypodinae (12 species), Diamesinae (2 species), Orthocladiinae (30 species), and Chironominae (43 species). The collections yielded a larger number of individuals and species than previous environmental studies in the Big Thicket. Twenty-two species are reported for the first time from Texas. The lowest number of individuals occupied the leaf debris with Rheotanytarsus sp. and Tanytarsus sp. 2 being dominant. The wood debris, probably the most stable of the substrates, contained the highest number of species with Tanytarsus sp. 2 being dominant. Most individuals occurred in the sandy bottom where Lopescladius sp. was dominant. Tanytarsus sp. 1 occurred in over 65 percent of the samples. The populations were generally higher during the autumn. This was probably a result of the life cycle and the effects of environmental factors. More younger instars occurred during the late summer and autumn. Also, water flow during the summer and autumn was low, providing a more stable environment, promoting chironomid population growth.
    Type of Medium: Electronic Resource
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  • 7
    Publication Date: 2017-12-18
    Description: Emotional events are often remembered better than neutral events, a benefit that many studies have hypothesized to depend on the amygdala’s interactions with memory systems. These studies have indicated that the amygdala can modulate memory-consolidation processes in other brain regions such as the hippocampus and perirhinal cortex. Indeed, rodent studies have demonstrated that direct activation of the amygdala can enhance memory consolidation even during nonemotional events. However, the premise that the amygdala causally enhances declarative memory has not been directly tested in humans. Here we tested whether brief electrical stimulation to the amygdala could enhance declarative memory for specific images of neutral objects without eliciting a subjective emotional response. Fourteen epilepsy patients undergoing monitoring of seizures via intracranial depth electrodes viewed a series of neutral object images, half of which were immediately followed by brief, low-amplitude electrical stimulation to the amygdala. Amygdala stimulation elicited no subjective emotional response but led to reliably improved memory compared with control images when patients were given a recognition-memory test the next day. Neuronal oscillations in the amygdala, hippocampus, and perirhinal cortex during this next-day memory test indicated that a neural correlate of the memory enhancement was increased theta and gamma oscillatory interactions between these regions, consistent with the idea that the amygdala prioritizes consolidation by engaging other memory regions. These results show that the amygdala can initiate endogenous memory prioritization processes in the absence of emotional input, addressing a fundamental question and opening a path to future therapies.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 8
    Publication Date: 2016-08-03
    Description: Profiling of 16S rRNA gene sequences is an important tool for testing hypotheses in complex microbial communities, and analysis methods must be updated and validated as sequencing technologies advance. In host...
    Electronic ISSN: 1756-0500
    Topics: Biology , Medicine
    Published by BioMed Central
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  • 9
    Publication Date: 2013-09-07
    Description: A 50:50 vol% MgO – Y 2 O 3 nanocomposite with ~150 nm grain size was prepared in an attempt to make 3–5 μm infrared-transmitting windows with increased durability and thermal shock resistance. Flexure strength of the composite at 21°C is 679 MPa for 0.88 cm 2 under load. Hardness is consistent with that of the constituents with similar grain size. For 3-mm-thick material at 4.85 μm, the total scatter loss is 1.5%, forward scatter is 0.2%, and absorptance is 1.8%. Optical scatter below 2 μm is 100%. Variable intensity OH absorption (~6% absorptance) is observed near 3 μm. The refractive index is ~0.4% below the volume-fraction-weighted average of those of the constituents. Thermal expansion is equal to the volume-fraction-weighted average of expansion of the constituents. Specific heat capacity is equal to the mass-fraction-weighted average of heat capacities of the constituents. Thermal conductivity lies between those of the constituents up to 1200 K. Elastic constants lie between those of the constituents. The Hasselman mild thermal shock resistance parameter for the composite is twice as great as that of common 3–5 μm window materials, but half as great as that of c -plane sapphire.
    Print ISSN: 0002-7820
    Electronic ISSN: 1551-2916
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Wiley
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  • 10
    Publication Date: 1972-02-01
    Print ISSN: 0021-9584
    Electronic ISSN: 1938-1328
    Topics: Chemistry and Pharmacology , Education
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