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  • 1
    Electronic Resource
    Electronic Resource
    Dynamics of Antarctic penguin populations in relation to inter-annual variability in sea ice distribution (1996)
    Springer
    Polar biology 16 (1996), S. 321-330 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  To investigate the role of sea ice cover on penguin populations we used principal component analysis to compare population variables of Adélie (Pygoscelis adeliae) and chinstrap (Pygoscelis antarctica) penguins breeding on Signy Island, South Orkney Islands with local (from direct observations) and regional (from remote sensing data) sea ice variables. Throughout the study period, the Adélie penguin population size remained stable, whereas that of chinstrap penguins decreased slightly. For neither species were there significant relationships between population size and breeding success, except for an apparent inverse density-dependent relationship between the number of Adélie breeding pairs and the number of eggs hatching. For both species, no general relationship was found between either population size or breeding success and the local sea ice conditions. However, the regional sea ice extent at a particular time prior to the start of the breeding season was related to the number of birds that arrived to breed. For both species, this period occurred before the sea ice reached its maximum extent and was slightly earlier for Adélie than for chinstrap penguins. These results suggest that sea ice conditions outside the breeding season may play an important role in penguin population processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003000050059
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Comparison of Isoplanatic Angles Derived from Thermosonde and Optical Measurements (1999)
    Springer
    Pure and applied geophysics 156 (1999), S. 503-524 
    Details
    ISSN: 1420-9136
    Keywords: Key Words: Optical turbulence, thermosonde, isoplanometer, isoplanatic angle.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract —A comparison of isoplanatic angles θ 0 derived from (1) balloon-borne in situ measurements of the index of refraction structure constant (C n 2) profiles and (2) ground-based optical measurements of stellar intensity fluctuations using an isoplanometer is presented. Concurrent data taken over a six-day period in the spring of 1986 show reasonably good agreement between the mean values determined by the two methods. Comparisons in light of meteorological conditions suggest an isoplanatic angle behavior consistent with the Kelvin-Helmholtz instability where the best correlation was found between the optically-measured isoplanatic angle and the layer-averaged wind shear. Differences between the two measurement methods are largest for isoplanometer azimuth angles perpendicular to the balloon trajectory and for lower values of mean shear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000240050310
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  • 3
    Electronic Resource
    Electronic Resource
    Lévy flight search patterns of wandering albatrosses (1996)
    [s.l.] : Nature Publishing Group
    Nature 381 (1996), S. 413-415 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We collected data over a three-month summer period as part of a study of the foraging biology of albatrosses in the South Atlantic5. Electronic recording devices were attached to the legs of five different adult albatrosses on Bird Island, South Georgia (54° 00' S, 38 ° 06' W), on 19 ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/381413a0
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  • 4
    Electronic Resource
    Electronic Resource
    Krill biomass in the Atlantic (1995)
    [s.l.] : Nature Publishing Group
    Nature 373 (1995), S. 201-202 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR - Acoustic target strength (TS)1 is an important parameter when using acoustic survey data to estimate the abundance of Antarctic krill (Euphausia superba Dana). Recently, when the TS of krill was reassessed2,3, it emerged that the previous values had been too high, leading to unrealistically ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/373201b0
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  • 5
    Electronic Resource
    Electronic Resource
    Altered neuronal distribution of parvalbumin in anterior cingulate cortex of rabbits exposed in utero to cocaine (1996)
    Springer
    Experimental brain research 112 (1996), S. 359-371 
    Details
    ISSN: 1432-1106
    Keywords: Parvalbumin ; Anterior cingulate cortex ; Cocaine ; Prenatal ; Gabaergic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous studies of rabbits exposed in utero to cocaine have revealed an increase in the number of neurons which are GABA immunoreactive in the anterior cingulate cortex (ACC), suggesting a cocaine-elicited modification in the balance of excitatory and inhibitory interactions. Of the major calcium binding proteins expressed by different subgroups of GABAergic neurons, parvalbumin has been observed in conditions involving excess excitation, and may serve to protect neurons from excitotoxicity. In the present study, we used immunocy-tochemistry to compare the effects of prenatal cocaine exposure on the postnatal development of parvalbumin immunoreactivity in interneurons of the visual cortex (VC) and ACC. We determined the number and laminar distribution of parvalbumin immunoreactive neurons, and we also assessed the distribution of parvalbumin immunoreactivity within primary, secondary and tertiary dendrites of neurons in these two cortical areas. In both ACC and VC, parvalbumin immunoreactive neurons were first observed around postnatal day 10 (P10) and their number increased rapidly from P10 to P20. At all ages studied (P10 to P60) there was no difference between cocaine-exposed and saline control animals in the number or laminar distribution of parvalbumin immunoreactive neurons in either cortical area. However, the distribution of parvalbumin immunoreactivity within dendrites revealed a significant difference between cocaine-exposed and saline control animals in ACC but not in VC. In ACC, at all ages studied, there was an increase in the number of primary, secondary and tertiary dendrites which were parvalbumin immunoreactive in cocaine-exposed animals compared with saline controls. This difference was most striking in secondary dendrites, and in laminae V and VI. The effect was observed at doses of 4 and 3 mg/kg per injection but not at 2 mg/kg per injection. In contrast to ACC, in VC there was no difference in the number of immunoreactive dendrites in cocaine-exposed animals compared with saline controls. These observations are consistent with the hypothesis that the ACC of rabbits exposed in utero to cocaine is characterized by altered excitatory/inhibitory interactions. ACC receives a dense dopaminergic input, but VC receives minimal dopaminergic innervation. Mechanisms by which the action of cocaine on the developing dopaminergic system may modify the balance of excitation and inhibition in ACC are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227942
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  • 6
    Electronic Resource
    Electronic Resource
    Cocaine administration in pregnant rabbits alters cortical structure and function in their progeny in the absence of maternal seizures (1997)
    Springer
    Experimental brain research 114 (1997), S. 433-441 
    Details
    ISSN: 1432-1106
    Keywords: Key words Cocaine ; Development ; MAP2 ; D1dopamine receptor ; Parvalbumin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Previous studies have reported that cocaine exposure in utero results in structural and functional alterations in the development of the anterior cingulate cortex (ACC). In the present study, the effects of maternal cocaine dosage and of cocaine-elicited maternal seizures on the progeny were studied. The incidence of maternal generalized tonic clonic seizures (GTCSs) elicited by cocaine was recorded. No GTCSs were elicited in pregnant rabbits by doses of 2 or 3 mg/kg of cocaine, but GTCSs were sometimes elicited by the highest dose (4 mg/kg per injection). We analyzed the offspring of cocaine-exposed and control animals using three assays of ACC development: (i) the structure of apical dendrites of pyramidal neurons, (ii) the distribution of a calcium binding protein (parvalbumin) in the dendrites of GABAergic neurons, and (iii) coupling of D1-like receptors and their G proteins. In all progeny of rabbits exposed to 3 or 4 mg/kg of cocaine during pregnancy, there was a significant change in the structure of apical dendrites, a significant increase in the number of dendrites of GABAergic neurons which were parvalbumin immunoreactive, and a significant reduction in D1/G protein coupling. In assays of apical dendrites, the effects on offspring of rabbits given 2 mg/kg cocaine were as pronounced as in offspring of rabbits given 3 or 4 mg/kg, but the effects on parvalbumin immunoreactivity and D1/G protein coupling were reduced at this low dose. Thus, previous findings of ACC developmental abnormalities in offspring of rabbits given a dose of 4 mg/kg were replicated, the effects were shown to be dose-related and to be independent of maternal seizures. A mechanism by which dysfunction of the D1receptor system could mediate cocaine-associated changes in all three parameters of ACC structure and function is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00005652
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  • 7
    Electronic Resource
    Electronic Resource
    Laparoscopically assisted abdominal aortic aneurysm repair (1996)
    Springer
    Surgical endoscopy and other interventional techniques 10 (1996), S. 1136-1139 
    Details
    ISSN: 1432-2218
    Keywords: Key words: Laparoscopy — Vascular — Abdominal aortic aneurysm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Laparoscopic surgery decreases postoperative pain and length of hospital stay. Whether laparoscopically assisted abdominal aortic aneurysm (AAA) repair can be safely and reliably performed is unknown. This prospective study was designed to establish the feasibility of laparoscopically assisted AAA repair and its effects on intraoperative and postoperative variables. Methods: With IRB approval, 10 patients with infrarenal AAA requiring a tube graft underwent laparoscopically assisted AAA repair. The procedure consisted of laparoscopic dissection of the aneurysm neck and iliac vessels. Then, through an 8–11-cm minilaparotomy, a standard endoaneurysmorrhaphy was performed. Data included laparoscopic and total operative times, blood loss, fluid requirements, duration of nasogastric suction (NGT), and lengths of intensive care unit (ICU) and postoperative hospital stays. Results: Laparoscopically assisted AAA was completed in nine of 10 patients. The first patient was converted to a standard incision because the aneurysm neck could not be adequately dissected. Laparoscopic and total operative times were 1.8 ± 0.4 and 4.5 ± 0.7 h, respectively. Mean blood loss was 1 ± 0.6 l. Intraoperative fluid requirement was 6.6 ± 1.3 l. The duration of NGT suction was 1.8 ± 1.0 days. The ICU stay was 2.1 ± 0.8 days and hospital stay was 6.7 ± 2.5 days. There were two minor complications and no deaths. Conclusions: Laparoscopically assisted AAA repair is technically feasible with acceptable blood loss, operative time, morbidity, and mortality. Potential advantages may be early removal of the NGT and shorter ICU and hospital stays. Prospective randomized trials are needed to determine if laparoscopically assisted AAA repair is advantageous.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004649900265
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  • 8
    Electronic Resource
    Electronic Resource
    Laparoscopic-assisted abdominal aortic aneurysm repair (1995)
    Springer
    Surgical endoscopy and other interventional techniques 9 (1995), S. 905-907 
    Details
    ISSN: 1432-2218
    Keywords: Laparoscopy ; Laparoscopic-assisted abdominal aortic aneurysm repair ; Vascular
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Since the advent of laparoscopy, the sweeping changes seen in general surgery have not been paralleled in vascular surgery. There have been case reports of laparoscopic-assisted aortobifemoral bypass for occlusive disease. Because aneurysmal disease comprises the majority of aortic surgery, we pursued animal and cadaveric feasibility studies for laparoscopic-assisted abdominal aortic aneurysm (AAA) repair. We present a case report of the first clinical case performed under Institutional Review Board protocol using this technique. The patient was a 62-year-old male with a 6-cm infrarenal AAA. After obtaining a pneumoperitoneum, a modified fish retractor was used to exclude the bowel. Ten 11-mm ports provided access to laparoscopically dissect the neck of the aneurysm and the iliac vessels. Then, a 10-cm minilaparotomy was performed and standard vascular clamps were inserted via the port incisions. Standard aneurysmorraphy was performed with a polytetrafluoroethylene (PTFE) tube graft. Laparoscopy conferred three major benefits: better visualization of the aneurysm neck, less bowel manipulation, and avoidance of hypothermia. This case report illustrates the feasibility of laparoscopic-assisted aneurysm repair. Controlled human studies will define the role of laparoscopy in AAA surgery.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00768889
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    Paper (German National Licenses)
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  • 9
    Electronic Resource
    Electronic Resource
    Dynamics of antarctic penguin populations in relation to inter-annual variability in sea ice distribution (1996)
    Springer
    Polar biology 16 (1996), S. 321-330 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract To investigate the role of sea ice cover on penguin populations we used principal component analysis to compare population variables of Adélie (Pygoscelis adeliae) and chinstrap (Pygoscelis antarctica) penguins breeding on Signy Island, South Orkney Islands with local (from direct observations) and regional (from remote sensing data) sea ice variables. Throughout the study period, the Adélie penguin population size remained stable, whereas that of chinstrap penguins decreased slightly. For neither species were there significant relationships between population size and breeding success, except for an apparent inverse density-dependent relationship between the number of Adélie breeding pairs and the number of eggs hatching. For both species, no general relationship was found between either population size or breeding success and the local sea ice conditions. However, the regional sea ice extent at a particular time prior to the start of the breeding season was related to the number of birds that arrived to breed. For both species, this period occurred before the sea ice reached its maximum extent and was slightly earlier for Adélie than for chinstrap penguins. These results suggest that sea ice conditions outside the breeding season may play an important role in penguin population processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02342178
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    Paper (German National Licenses)
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of Maturation on the Phospholipid and Phospholipid Fatty Acid Compositions in Primary Rat Cortical Astrocyte Cell Cultures (1997)
    Springer
    Neurochemical research 22 (1997), S. 1205-1213 
    Details
    ISSN: 1573-6903
    Keywords: Plasmalogen ; phospholipid ; astrocytes ; docosahexaenoic acid ; arachidonic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Phospholipid and phospholipid fatty acid compositional changes were studied in rat cortical astrocytes during dibutyryl cyclic adenosine monophosphate (dBcAMP, 0.25 mM) treatment starting after 14 days in culture (DIC). After 15 DIC, ethanolamine- and choline glycerophospholipid levels were increased 1.2- and 1.3-fold, respectively in treated compared to control cells. However, after 21 and 28 DIC, these levels were not significantly different between groups. Both groups had an increase in phosphatidylserine levels with increasing time in culture. Similarly, ethanolamine plasmalogen levels were transiently elevated after 21 DIC, but returned to previous levels after 28 DIC. The phospholipid fatty acid compositions for the acid stable and labile ethanolamine- and choline glycerophospholipids indicated that in dBcAMP treated cells, 20:4 n-6 and 22:6 n-3 proportions were elevated with increasing time in culture relative to control cells. As 20:4 n-6 proportions increased, there was a concomitant decrease in 20:3 n-9 proportions, suggesting an up regulation of n-6 series elongation and desaturation. In contrast, in control cells, the 20:4 n-6 proportions decreased with a corresponding increase in the 20:3 n-9 proportions. Thus, in treated cells, the cellular phospholipid fatty acid composition was dramatically different than control cells, suggesting that dBcAMP treatment may act to increase fatty acid elongation and desaturation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021924711675
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