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  • 1
    Electronic Resource
    Electronic Resource
    On the uptake of ornithogenic products by plants on the inland mountains of Dronning Maud Land, Antarctica, using stable isotopes (1998)
    Springer
    Polar biology 20 (1998), S. 107-111 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Breeding snow petrels (Pagodroma nivea) may be a major source of nutrients for the ecosystems on the inland nunataks (mountain outcrops) of continental Antarctica. To test this theory, the δ15N and δ13C values of soil and plants (moss, lichen and algae) from 11 nunataks with and without breeding snow petrels in northwestern Dronning Maud Land were compared. High δ15N values in all samples from nunataks with breeding birds provide a strong indication of the presence of breeding birds, as well as the use of bird-derived nitrogen by the plants of these ecosystems. The δ13C values showed little difference between the nunataks and are not a useful indicator of bird effects on ecosystem development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003000050283
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  • 2
    Electronic Resource
    Electronic Resource
    Bird effects on organic processes in soils from five microhabitats on a nunatak with and without breeding snow petrels in Dronning Maud Land, Antarctica (1998)
    Springer
    Polar biology 20 (1998), S. 112-120 
    Details
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Five microhabitat types with varying degrees of bird influence were examined. Soils were collected from open polygons, under mosses and bird nests on a nunatak with breeding snow petrels (Pagodroma nivea) and from open polygons and under mosses on a non-bird nunatak. Nutrient levels (total N and P, nitrate, nitrite and ammonia), moisture levels and δ 15N values were determined and the organic processes of nitrogen fixation (acetylene reduction) and soil respiration (CO2 flux) were examined. Nests represented the most favourable microhabitat type for soil respiration having the highest nutrient levels and most favourable temperature and moisture regimes. The soils under mosses were also favourable and appear to act as a nutrient sink for nutrients originating from the nests. The open polygons were the least favourable for biological activity. There was little nitrogen fixation in any of the soils except for the soils under mosses from the non-bird nunatak. Fixation is possibly limited in favourable microhabitat types on the bird nunatak by high nitrogen levels. These results were confirmed by the δ 15N results, which had high values typical of a seabird signal in the soils from the bird nunatak and values near zero, typical of soils containing fixed nitrogen, on the non-bird nunatak.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003000050284
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  • 3
    Electronic Resource
    Electronic Resource
    Nonstructural carbohydrate allocation following different frequencies of simulated browsing in three semi-arid shrubs (1995)
    Springer
    Oecologia 102 (1995), S. 238-245 
    Details
    ISSN: 1432-1939
    Keywords: Browsing responses ; Semi-arid shrubs ; Nonstructural carbohydrate accumulation ; Regrowth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nonstructural carbohydrate allocation patterns in response to different frequencies of simulated browsing (leaf and twig removal) were studied in the following semi-arid shrubs: Osteospermum sinuatum, a dwarf deciduous shrub, Pteronia pallens, a dwarf evergreen shrub, and Ruschia spinosa, a dwarf leaf-succulent shrub. Simulated browsing at all frequencies resulted in the elevation, or had no effect, on total nonstructural carbohydrate (TNC) concentrations of O. sinuatum plant parts, and resulted in the decrease in TNC concentrations of R. spinosa plant parts. The responses of P. pallens were intermediate with elevations as well as declines in TNC concentrations of plant parts measured in response to various clipping frequencies. At the low frequency of simulated browsing (every 26 weeks) elevations in plant TNC content were measured in the two non-succulent shrubs O. sinuatum and P. pallens. It was concluded that the overcompensation with respect to TNC accumulation observed in the two non-succulent species represents one of the ways in which excess photosynthate is utilized by browsed shrubs with a limited regiowth potential. Simulated browsing was the least detrimental with respect to biomass production to the non-succulent O. sinuatum and P. pallens, and most injurious to the leaf-succulent shrub, R. spinosa. The observed TNC allocation patterns could not adequately explain the variation among species in the production of new growth and it was concluded that some factor(s) other than the carbon resource was limiting regrowth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00333256
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  • 4
    Electronic Resource
    Electronic Resource
    Impacts of invading N2-fixing Acacia species on patterns of nutrient cycling in two Cape ecosystems: evidence from soil incubation studies and 15N natural abundance values (1995)
    Springer
    Oecologia 101 (1995), S. 375-382 
    Details
    ISSN: 1432-1939
    Keywords: Nitrogen isotope discrimination ; Cape floristic region ; Fynbos ; Strandveld ; Acacia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study examines the impacts of woody, N2-fixing invasive Acacia spp. on the patterns of nutrient cycling in two invaded ecosystems of differing nutrient status in the Cape floristic region. Patterns of soil nutrient mineralization were measured by a field incubation method while the significance of the fixation process in altering nutrient cycling was assessed by the δ15N natural abundance technique. The results confirm earlier reports that invasion by woody shrubs results in organic matter and nutrient enrichment of surface soils of both ecosystems. However, patterns of nutrient availability (phosphorus and nitrogen) were not necessarily enhanced. In the more fertile strandveld both phosphorus and nitrogen (significant at P〈0.10) showed trends towards enhanced annual mineralization rates upon invasion, while in the low nutrient fynbos system only phosphorus followed this trend. It is unclear whether this differential response is a consequence of plant- or soil-derived feedbacks on the decomposition processes in each system. The δ15N values of the soils from the invaded sites of both ecosystems indicated a strong influence of the alien species on the soil nitrogen component. However, as with other studies of natural ecosystems, the contribution of nitrogen from fixation could not be readily quantified with the δ15N natural abundance method because of problems in selecting suitable non-N2-fixing reference plants. A technique of disrupting nodule structure and function, by fumigation with O2, to obtain the δ15N value of a non-N2-fixing speciment of the study species was tried and found to overcome some of the problems associated with the lack of suitable reference plants. With this technique it was possible to detect the almost total dependence of A. saligna on N2-fixation in the fynbos soils with their low nitrogen mineralization rates. In the strandveld ecosystem with much higher soil nitrogen release rates A. cyclops was only partly dependent on fixation (about half) for its nitrogen. The nutrient enrichment of both ecosystems and trends towards enhanced rates of nutrient mineralization could have profound implications on the long-term success of alien invader clearing operations and the restoration of the indigenous flora at these sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328825
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  • 5
    Electronic Resource
    Electronic Resource
    Salmonella enteritidis infiziertes falsches Aneurysma der Arteria femoralis superficialis bei einem HIV-seropositiven Patienten (1998)
    Springer
    Der Chirurg 69 (1998), S. 204-206 
    Details
    ISSN: 1433-0385
    Keywords: Key words: Peripheral arterial aneurysm ; HIV infection ; Salmonella enteritidis. ; Schlüsselwörter: Peripheres arterielles Aneurysma ; HIV-Infektion ; Salmonella enteritidis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. Im Verlauf einer Infektion mit dem human immunodeficiency virus (HIV) können sehr verschiedenartige Komplikationen mit Beteiligung aller Organsysteme auftreten. Komplikationen des Gefäßsystems, die eine chirurgische Therapie erfordern, sind hingegen selten. Wir berichten über einen 67 jährigen HIV-seropositiven Patienten, bei dem ein großer Oberschenkelabsceß operiert wurde. Intraoperativ stellte sich der Befund unerwarteterweise als ein mykotisches Aneurysma der A. femoralis superficialis dar, bei dem als ursächlicher Erreger Salmonella enteritidis gefunden wurde. Es ist anzunehmen, daß bei ansteigender Zahl von HIV-infizierten Patienten Komplikationen des Gefäßsystems mit der Notwendigkeit einer gefäßchirurgischen Versorgung ebenfalls häufiger werden. Bei der Diagnosestellung und Therapieplanung von HIV-infizierten Patienten sollte daher schon frühzeitig eine HIV-bedingte Gefäßerkrankung mitbedacht werden.
    Notes: Summary. In the course of an infection with human immunodeficiency virus, a large variety of complications affecting all organ systems can occur. However, complications affecting the vascular system demanding surgical intervention are rare. In the case presented we report a 67-year-old HIV-seropositive patient who underwent surgery for a huge abscess in the thigh. Intraoperatively unexpectedly we found a mycotic aneurysm of the femoral superficial artery and the causactive bacterium proved to be Salmonella enteritidis. Because of the rising number of HIV-infected patients we suspect that the amount of complications involving the vascular system and demanding surgical intervention will also increase. Therefore, when diagnosing and deciding on therapy for patients with AIDS, the physician must be awaren that vascular complications due as a result of HIV infection might occur more frequently in the future.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001040050397
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  • 6
    Electronic Resource
    Electronic Resource
    Electromyographic study on the function of tendon transfers in radial palsy (1997)
    Springer
    Der Orthopäde 26 (1997), S. 673-683 
    Details
    ISSN: 1433-0431
    Keywords: Key words EMG • Tendon transfers • Radial palsy ; Schlüsselwörter EMG • Radialisersatzoperation • Motorische Ersatzplastik
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In dieser elektromyographischen Studie werden die Funktionsmechanismen der Radialisersatzoperation untersucht: 18 Patienten wurden mit 16 gesunden Personen verglichen. Erfaßt wurde das intramuskuläre EMG von 4 Muskeln während Extensions-Flexions-Bewegungen des Handgelenks bzw. des Daumens und der Finger. Die Daten wurden auf einem FM-Bandgerät zur späteren Auswertung gespeichert. Überraschenderweise zeigten sich in den transferierten Flexoren meist doppelte, voneinander unterscheidbare EMG-Aktivitätsphasen: Eine 1. Komponente im Sinne der „neuen“ und eine 2. im Sinne der „alten“ Bewegungsrichtung. Deshalb wurde für jeden Muskel eine „Extensionsquote“ (EQ) errechnet. Sie entspricht seiner EMG-Aktivität während der Extension ausgedrückt in Prozent seiner gesamten EMG-Aktivität. In nicht transferierten Flexoren war die EQ niedrig (11–27 %). Hohe EQ-Werte (69–91 %) wurden dagegen in physiologischen Extensoren von Vergleichspersonen ermittelt. Bei nur 6 von 18 Patienten zeigten transferierte Flexoren eine EQ, die im Bereich der physiologischen Extensoren lag (≥ 69 %). Die besten funktionellen Ergebnisse erbrachte dabei der transferierte M. flexor carpi ulnaris (Median der EQ 68 %). Die EQ des transferierten M. pronator teres war niedrig (Median 18 %) und in allen Fällen kleiner als diejenige des M. flexor carpi ulnaris (p 〈 0,05). Nach diesen Daten eignet sich der M. pronator teres nicht als Ersatz für Streckmuskeln. Oberflächliche Fingerbeuger arbeiten dagegen synergistisch mit Handgelenkstreckern. Entsprechend den dabei wirksamen Ia-Reflexmustern sollten diese Muskeln eine gute Wahl zum Ersatz der Handgelenkstreckung sein.
    Notes: Summary The aim of this electromyographic study was to evaluate the functional result of tendon transfers for radial palsy. Eighteen patients were compared to 16 healthy volunteers. The intramuscular emg of four muscles was recorded in parallel during extension-flexion movements of the wrist and fingers. The data were stored on FM tape and evaluated off-line. Contrary to expectations, transferred flexor muscles revealed only part of their overall emg activity during extension. Therefore, an ”extensor quota” (EQ) was calculated for each muscle. It reflects its emg activity during extension as part of its entire emg activity. In non-transferred flexors EQ was low (11–27 %). High EQ values (69–91 %) were seen in genuine extensors of healthy persons. In only 6 of 18 patients did transferred flexors show an EQ equivalent to genuine extensors (≥ 69 %). Best functional results were seen in transferred flexor carpi ulnaris (median EQ 68 %). The EQ of transferred pronator teres was low (median 18 %) and minor to flexor carpi ulnaris in each patient (P 〈 0.05). It is concluded that in cases of radial palsy, pronator teres is not suitable for replacing extensor muscles. Superficial flexors of the fingers, however, work in synergy with extensors of the wrist. According to the Ia reflex connections involved, these muscles should be a good choice for regaining extension of the wrist.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00003427
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  • 7
    Electronic Resource
    Electronic Resource
    Clinical experiences in tendon transfers for radial nerve palsy by a new method of Wiedemann (1997)
    Springer
    Der Orthopäde 26 (1997), S. 684-689 
    Details
    ISSN: 1433-0431
    Keywords: Key words Radial nerve palsy • Tendon transfer ; Schlüsselwörter Radialislähmung • Motorische Ersatzoperation • Radialisersatzoperation • Mehrsehnenplastik
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zur Behandlung der irreversiblen Parese des N. radialis werden unterschiedliche Sehnentransferoperationen empfohlen, wobei die Eignung der jeweils verwendeten Muskeln für die später zu erfüllenden Streckfunktionen an der Hand von den einzelnen Autoren kontrovers diskutiert werden. Neurophysiologische Untersuchungen zum Umlernverhalten von transponierten Muskeln markierten den M. pronator teres, der bei der Methode nach Merle d'Aubigne auf den M. extensor carpi radialis longus und brevis transferiert wird, als schlechten Ersatzstrecker im Handgelenk. Deshalb wurde von uns der nach neurophysiologischen Überlegungen besser geeignete M. flexor digitorum superficialis von D 3 und von D 4 für den Transfer zum M. extensor carpi radialis longus und brevis für die Streckung im Handgelenk verwendet. Es wurden bei uns von 1994–1997 4 Patienten mit dieser neuen Muskelumstellungskombination operiert. Bisher konnten 2 Patienten 2 Jahre postoperativ nachuntersucht werden. Diese beiden Patienten zeigten bei der Handgelenkstreckung bessere Werte als Patienten mit Pronator-teres-Transfer. Die bisherigen guten klinischen Ergebnisse dieser neuen Muskelumstellungskombination ermutigen zu ihrer weiteren Anwendung.
    Notes: Summary Many modifications of tendon transfers have been described in the treatment of radial nerve palsy. Controversy persists over the muscles of choice to get the best results in motion of wrist and fingers. Patients with radial nerve palsy and treated by the methode of Merle d'Aubigne in neurophysiological tests showed that the pronator teres did not work very well for extending the wrist. Thinking about the neurophysiologic principles it seemed that the flexor digitorum superficialis of the middle and ring fingers would make a better substitute for the wrist extension. From 1994 to 1997 four patients with radial nerve palsy had a transfer of the flexor digitorum superficialis tendons from the middle and ring fingers to the tendons of extensor carpi radialis longus and brevis additional the flexor carpi ulnaris and palmaris longus transfers. The functional recovery of two patients has been tested. The functional range of wrist motion of this two patients has been better than in patients with pronator teres transfers. It can be concluded that the new modification of tendon transfers is a good way of treatment of radial nerve palsy and should be done further.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00003428
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  • 8
    Electronic Resource
    Electronic Resource
    Prognosefaktoren der perforierten Dickdarmdiverticulitis (1998)
    Springer
    Der Chirurg 69 (1998), S. 443-449 
    Details
    ISSN: 1433-0385
    Keywords: Key words: Diverticular disease ; Emergency operation ; Prognostic factors ; Morbidity ; Mortality. ; Schlüsselwörter: Dickdarmdiverticulitis ; Notfalloperation ; Prognosefaktoren ; Morbidität ; Letalität.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung. In einer retrospektiven Studie wurden die Prognosefaktoren bzgl. Morbidität und Letalität von 105 notfallmäßig operierten Patienten mit perforierter Dickdarmdiverticulitis untersucht. Bei unterschiedlichem Ausprägungsgrad der Diverticulitis (Hinchey-Klassifikation I: 8,6 %, II: 14,3 %, III: 57,1 %, IV: 20,0 %) betrug die Letalität 12,4 %. In der multivariaten Analyse waren die präoperative Sepsis mit Leukopenie und Leberfunktionsstörungen, kardiale Risikofaktoren und die Adipositas eigenständige prognoseverschlechternde Parameter. Bei gleichzeitig vorliegender Immunsuppression kam es zu einem deutlichen Anstieg der Letalität auf 33 %. Das Ausmaß der Peritonitis zeigte keinen Einfluß auf die Prognose. Das Operationsverfahren (Kontinuitätsresektion 12,4 %, Diskontinuitätsresektion 61,9 %, nicht resezierende Verfahren 25,7 %) hatte multivariat nur einen Einfluß auf die vermehrte Ausbildung allgemeiner Komplikationen.
    Notes: Summary. Morbidity and mortality after emergency procedures in 105 patients with perforated colonic diverticulitis were evaluated in a retrospective study. In different stages of diverticulitis (Hinchey classification: I, 8.6 %; II, 14.3 %; III, 57.1 %; IV, 20.0 %) mortality was 12.4 %. Preoperative sepsis syndrome with leucopenia and disturbed liver function, cardiac risk factors and obesity were independent prognostic factors in multiple logistic regression. Accompanied by immunosuppression the mortality rate remarkably increased to 33 %. The stage of peritonitis showed no influence on the prognosis. In multivariate analysis, surgical procedure (primary resection 12.4 %, Hartmann's procedure 61.9 %, non-resection procedures 25.7 %) showed influence only on increased general complications.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001040050436
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  • 9
    Electronic Resource
    Electronic Resource
    Desertification of the eastern Karoo, South Africa: Conflicting paleoecological, historical, and soil isotopic evidence (1995)
    Springer
    Environmental monitoring and assessment 37 (1995), S. 159-177 
    Details
    ISSN: 1573-2959
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The desertification debate in South Africa has benefitted greatly in recent years from the contributions of a wide range of disciplines. In this paper we review the conflicting and supporting evidence for degradation in the eastern Karoo as reported in recent archaeological, historical, and stable carbon isotope studies as it relates to three key aspects of the debate: the precolonial environment, the rate and nature of change, and the relative contributions of humans and climate to the process. First, all studies suggest a greater grassiness at some time in the past, but researchers disagree on the timing of the switch to more shrubby conditions in the eastern Karoo. Second, regional rainfall records for the past 2 decades reveal an above-average rainfall period, and numerous long-term surveys show an increase in grass cover over the same period. These findings question the expanding Karoo hypothesis as well as the argument that the Karoo's carrying capacity has decreased in recent years. Finally, the relative responsibilities of humans and climate in the degradation process remain poorly understood and generally have not formed the focus of investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00546887
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  • 10
    Electronic Resource
    Electronic Resource
    Soil nutrient dynamics and community boundaries in the Fynbos vegetation of South Africa (1997)
    Springer
    Plant ecology 130 (1997), S. 143-153 
    Details
    ISSN: 1573-5052
    Keywords: Community boundaries ; Fynbos ; Nitrogen ; Phosphorus ; Soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The relationship between changes in soil nutrient characteristics and fynbos community boundaries was investigated near Cape Agulhas, South Africa. Soil characteristics relating to total nutrient content (pH, total N and total P, organic carbon, and various cations) were assessed at sites along three transects crossing the boundaries between five plant communities. Dynamics of available N and P in soils of three communities were studied in the field over one year, using ion-exchange resins. There was a wide range in the degree of change in soil nutrient content across different community boundaries. The characteristics that varied most were pH, total N, Ca and total P. Differences in available nutrients among soils indicated that the communities in this landscape were associated with a mosaic of N and P availability. It is proposed that spatial variation in soil nutrient availability rather than total soil nutrient contents may be important in explaining landscape-level species distributions and community composition in nutrient-poor mediterranean-climate ecosystems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009742225383
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