151 research outputs found
GefÀhrdete Sandvegetation der nördlichen Oberrheinebene: vegetationsökologische Untersuchungen der Technischen UniversitÀt Darmstadt 1995 - 2013 im Landkreis Darmstadt-Dieburg und im Bereich der Stadt Darmstadt
Potential contribution of surface-dwelling Sargassum algae to deep-sea ecosystems in the southern North Atlantic
Deep-sea ecosystems, limited by their inability to use primary production as a source of carbon, rely on other sources to maintain life. Sedimentation of organic carbon into the deep sea has been previously studied, however, the high biomass of sedimented Sargassum algae discovered during the VEMA Transit expedition in 2014/2015 to the southern North Atlantic, and its potential as a regular carbon input, has been an underestimated phenomenon. To determine the potential for this carbon flux, a literature survey of previous studies that estimated the abundance of surface water Sargassum was conducted. We compared these estimates with quantitative analyses of sedimented Sargassum appearing on photos taken with an autonomous underwater vehicle (AUV) directly above the abyssal sediment during the expedition. Organismal communities associated to Sargassum fluitans from surface waters were investigated and Sargassum samples collected from surface waters and the deep sea were biochemically analyzed (fatty acids, stable isotopes, C:N ratios) to determine degradation potential and the trophic significance within deep-sea communities. The estimated Sargassum biomass (fresh weight) in the deep sea (0.07 â 3.75 g/m2) was several times higher than that estimated from surface waters in the North Atlantic (0.024 â 0.84 g/m2). Biochemical analysis showed degradation of Sargassum occurring during sedimentation or in the deep sea, however, fatty acid and stable isotope analysis did not indicate direct trophic interactions between the algae and benthic organisms. Thus, it is assumed that components of the deep-sea microbial food web form an important link between the macroalgae and larger benthic organisms. Evaluation of the epifauna showed a diverse nano- micro-, meio, and macrofauna on surface Sargassum and maybe transported across the Atlantic, but we had no evidence for a vertical exchange of fauna components. The large-scale sedimentation of Sargassum forms an important trophic link between surface and benthic production and has to be further considered in the future as a regular carbon input to the deep-sea floor in the North Atlantic
ReSurveyGermany: Vegetation-plot time-series over the past hundred years in Germany
Vegetation-plot resurvey data are a main source of information on terrestrial biodiversity change, with records reaching back more than one century. Although more and more data from re-sampled plots have been published, there is not yet a comprehensive open-access dataset available for analysis. Here, we compiled and harmonised vegetation-plot resurvey data from Germany covering almost 100 years. We show the distribution of the plot data in space, time and across habitat types of the European Nature Information System (EUNIS). In addition, we include metadata on geographic location, plot size and vegetation structure. The data allow temporal biodiversity change to be assessed at the community scale, reaching back further into the past than most comparable data yet available. They also enable tracking changes in the incidence and distribution of individual species across Germany. In summary, the data come at a level of detail that holds promise for broadening our understanding of the mechanisms and drivers behind plant diversity change over the last century
Irinotecan and temozolomide in combination with dasatinib and rapamycin versus irinotecan and temozolomide for patients with relapsed or refractory neuroblastoma (RIST-rNB-2011): a multicentre, open-label, randomised, controlled, phase 2 trial
Background
Neuroblastoma is the most common extracranial solid tumour in children. Relapsed or refractory neuroblastoma is associated with a poor outcome. We assessed the combination of irinotecanâtemozolomide and dasatinibârapamycin (RIST) in patients with relapsed or refractory neuroblastoma.
Methods
The multicentre, open-label, randomised, controlled, phase 2, RIST-rNB-2011 trial recruited from 40 paediatric oncology centres in Germany and Austria. Patients aged 1â25 years with high-risk relapsed (defined as recurrence of all stage IV and MYCN amplification stages, after response to treatment) or refractory (progressive disease during primary treatment) neuroblastoma, with Lansky and Karnofsky performance status at least 50%, were assigned (1:1) to RIST (RIST group) or irinotecanâtemozolomide (control group) by block randomisation, stratified by MYCN status. We compared RIST (oral rapamycin [loading 3 mg/m2 on day 1, maintenance 1 mg/m2 on days 2â4] and oral dasatinib [2 mg/kg per day] for 4 days with 3 days off, followed by intravenous irinotecan [50 mg/m2 per day] and oral temozolomide [150 mg/m2 per day] for 5 days with 2 days off; one course each of rapamycinâdasatinib and irinotecanâtemozolomide for four cycles over 8 weeks, then two courses of rapamycinâdasatinib followed by one course of irinotecanâtemozolomide for 12 weeks) with irinotecanâtemozolomide alone (with identical dosing as experimental group). The primary endpoint of progression-free survival was analysed in all eligible patients who received at least one course of therapy. The safety population consisted of all patients who received at least one course of therapy and had at least one post-baseline safety assessment. This trial is registered at ClinicalTrials.gov, NCT01467986, and is closed to accrual.
Findings
Between Aug 26, 2013, and Sept 21, 2020, 129 patients were randomly assigned to the RIST group (n=63) or control group (n=66). Median age was 5·4 years (IQR 3·7â8·1). 124 patients (78 [63%] male and 46 [37%] female) were included in the efficacy analysis. At a median follow-up of 72 months (IQR 31â88), the median progression-free survival was 11 months (95% CI 7â17) in the RIST group and 5 months (2â8) in the control group (hazard ratio 0·62, one-sided 90% CI 0·81; p=0·019). Median progression-free survival in patients with amplified MYCN (n=48) was 6 months (95% CI 4â24) in the RIST group versus 2 months (2â5) in the control group (HR 0·45 [95% CI 0·24-0·84], p=0·012); median progression-free survival in patients without amplified MYCN (n=76) was 14 months (95% CI 9â7) in the RIST group versus 8 months (4â15) in the control group (HR 0·84 [95% CI 0·51â1·38], p=0·49). The most common grade 3 or worse adverse events were neutropenia (54 [81%] of 67 patients given RIST vs 49 [82%] of 60 patients given control), thrombocytopenia (45 [67%] vs 41 [68%]), and anaemia (39 [58%] vs 38 [63%]). Nine serious treatment-related adverse events were reported (five patients given control and four patients given RIST). There were no treatment-related deaths in the control group and one in the RIST group (multiorgan failure).
Interpretation
RIST-rNB-2011 demonstrated that targeting of MYCN-amplified relapsed or refractory neuroblastoma with a pathway-directed metronomic combination of a multkinase inhibitor and an mTOR inhibitor can improve progression-free survival and overall survival. This exclusive efficacy in MYCN-amplified, relapsed neuroblastoma warrants further investigation in the first-line setting
<scp>ReSurveyEurope</scp>: A database of resurveyed vegetation plots in Europe
AbstractAimsWe introduce ReSurveyEurope â a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions.ResultsReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or coverâabundance classes such as variants of the BraunâBlanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020.ConclusionsReSurveyEurope is a new resource to address a wide range of research questions on fineâscale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the wellâestablished European Vegetation Archive (EVA). ReSurveyEurope data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.</jats:sec
Gisbert GroĂe-Brauckmann (1926-2001)
Am 25. April verstarb im 75. Lebensjahr nach langer schwerer Krankheit Gisbert GroĂe-Brauckmann. In Göttingen am 12. Mai 1926 geboren, wuchs er in einem durch die Altphilologie geprĂ€gten Elternhaus auf. Vater und GroĂvater waren Altphilologen; dennoch zeigte sich schon frĂŒh das besondere Interesse von Gisbert GroĂe-Brauckmann fĂŒr die Biologie und insbesondere die Botanik
Zur Soziologie Alnus incana-reicher Waldgesellschaften im Schwarzwald unter besonderer BerĂŒcksichtigung der PhĂ€nologie
Alnus incana-reiche Waldgesellschaften haben im Schwarzwald eine sehr spezifische Verbreitung und sind auf ein kleineres Gebiet sĂŒdlich und sĂŒdöstlich des Feldbergs beschrĂ€nkt, wo sie in einer Höhenlage von 620 bis 1100 m ĂŒ.M. stocken. Es handelt sich um winterkalte Gebiete mit 150 Frosttagen oder mehr, die wĂŒrmglazial ĂŒberformt wurden und mĂ€chtige fluvioglaziale Schotterkörper haben. Die GewĂ€sser erreichen ihre Abflussmaxima im April. In diesen Gebieten fehlt Alnus glutinosa aus wĂ€rmeklimatischen GrĂŒnden.
Es konnten mit Hilfe der pflanzensoziologischen Tabelle vier voneinander verschiedene Standortstypen ausgeschieden werden, die von der Grauerle besiedelt werden und z.T. kleinstandörtlich weiter untergliederbar sind: a) Der bach- und fluĂbegleitende Grauerlenwald (Alnetum incanae) mit den Subassoziationen "typicum" und "aceretosum" sowie Varianten und Höhenformen; b) der Alnus incana-Rangwald; c) der Alnus incana-Bruchwald; d) die Alnus incana-Carex remota-Ges. (nur als Fragment). Hinzu kommt als weiterer Typ der Alnus incana-Weidewald.
Besonderes Augenmerk galt der Untersuchung der SymphĂ€nologie verschiedener Höhenformen des Alnetum incanae, die eine Reihe zeitlich gestaffelter Blumenwellen erkennen lĂ€sst. Ferner wurden synökologische Untersuchungen (Bodenprofile, pH-Werte wĂ€hrend der Vegetationsperiode) durchgefĂŒhrt.
Alnus incana-reiche Gesellschaften des Schwarzwaldes sind aus biologischen, landschaftspflegerischen und landschaftsĂ€sthetischen GrĂŒnden besonders schĂŒtzenswerte Vegetationseinheiten.Alnus incana-rich forest communities in the Black Forest have a very specific distribution restricted to a small area south and southeast of the Feldberg, where they grow from 620 to 1100 m above sea level. These regions have rather low winter temperatures, with 150 or more frost days per year. These areas were formed during the WĂŒrm glacial period and have thick fluvioglacial deposits. Streamflow is highest in April. In these regions Alnus glutinosa is absent due to insufficient warmth.
By means of phytosociological tables it was possible to distinguish four site-related Alnus incana communities: a) Alnetum incanae along streams, with subassociations typicum and aceretosum plus different variants and altitudinal forms; b) Alnus incana community on slopes; c) Alnus incana swamp forest; d) Alnus incana-Carex remota community (only fragmentary stands). Grazed Alnus incana woodlands can be considered an additional type.
The comparative symphenological investigation of different altitudinal forms of the Alnetum incanae deserves special attention, since it shows a clear staggering of flowering times ("flowering waves"). Synecological investigations (soil profiles, pH measurements) were also carried out.
On account of their biological, ecological and aesthetical importance to the landscape, Alnus incana woodlands are especially deserving of protection
VerĂ€nderungen in montanen Borstgrasrasen durch DĂŒngung und Brachlegung : Antennaria dioica und Vaccinium vitis-idaea als Indikatoren
Durch vergleichende vegetationskundliche Untersuchungen in den Jahren 1977/78 und 1989 sowie Dauerquadrat-Untersuchungen konnte belegt werden, dass 2 Indikatorarten: Antennaria dioica (L.) Gaertn. und Vaccinium vitis-idaea L. sehr viel rascher auf DĂŒngungseinflĂŒsse reagieren als die Phytocoenose (Festuco-Genistetum sagittalis).
Aktualistische Vergleiche der pflanzenverfĂŒgbaren N- und P-Gehalte im Oberboden belegen gering erhöhte Ammonium-Werte in FlĂ€chen, denen die beiden Arten inzwischen fehlen. StĂ€rkere RĂŒckgĂ€nge in FlĂ€chen mit DĂŒngereinfluss zeigt auch Calluna vulgaris.
Schon bei geringen IntensitÀtssteigerungen der Rinderbeweidung wird Antennaria in dem dichter werdenden Rasen verdrÀngt, Vaccinium vitis-idaea stirbt bei Faeces-Einwirkung ab.
In Brachen verhalten sich beide Arten verschieden: Antennaria vermag sich in höherwĂŒchsigen Brachen nicht zu halten; Vaccinium vitis-idaea zeigt auch in Brachen gute VitalitĂ€t.
Antennaria dioica hat in extensiv beweideten FlĂ€chen und in Brachen unterschiedliche Wuchsformen: an offenen Stellen bildet die Pflanze oberirdische plagiotrop wachsende Stolonen; es können sich hier pro Jahr und Altrosette bis zu 5 junge Rosetten bilden. In höherwĂŒchsigen Brachen wachsen die Stolonen orthotrop und bilden einen Rosettenschopf, der bald sein Wachstum einstellt. Die Keimraten sind nach experimentellen Untersuchungen sehr gering; eine Samenbank wird nach allen bisherigen Befunden auch anderer Autoren nicht aufgebaut.
Floristische Ănderungen in Brachen, die auf atmogene N-Immissionen zurĂŒckgefĂŒhrt werden könnten, sind (noch) nicht festzustellen. Auch die Calluna-Populationen haben sich hier halten können, und die Standorte weisen in den Brache-UntersuchungsflĂ€chen keine Vergrasungserscheinungen auf.
Antennaria dioica und Vaccinium vitis-idaea eignen sich als Monitor-Organismen fĂŒr N-DĂŒnger-freie Bewirtschaftung.It was possible to show by comparative phytosociological research in 1977/78 and 1989 and by permanent-plot investigations, that the reaction of two indicator species (Antennaria dioica and Vaccinium vitis-idaea) to fertilization is quicker than the reaction of the phytocoenosis in general (Festuco-Genistetum sagittalis).
Comparisons of Nmin and Pmin contents in the Ah-horizon show slightly increased values of NH4-N in areas where both species were absent in 1989. Vanishing populations of Calluna vulgaris can also be recognized here.
Even if the increase of grazing intensity is low, Antennaria is displaced by the dense grass canopy while Vaccinium vitis-idaea dies from the direct influence of feces deposition.
Antennaria dioica and Vaccinium vitis-idaea show different behaviour in abandoned land. While Antennaria cannot exist at all, Vaccinium vitis-idaea still shows good vitality.
Antennaria shows different growth forms in extensively grazed areas and in fallow land, areas with gaps are characterized by creeping stolons with plagiotropic growth. In such situations Antennaria can produce up to five young rosettes per old rosette. In fallow land with tall grass the stolons grow orthotropically and produce a tuft of rosettes, which soon stops growing. Experiments have shown that the rates of germination are very low in such situations, and a soil seed bank has not been found by this or other authors.
Floristic changes in fallow land caused by atmogenic nitrogen immissions could not yet be identified including the continuation of the Calluna populations and the lack of increase of the grasses.
Antennaria dioica and Vaccinium vitis-idaea show themselves as indicator species for cultivation without N-fertilization
1. Workshop der Floristisch-soziologischen Arbeitsgemeinschaft âFloristik und Geobotanik - BeitrĂ€ge zu angewandten Fragestellungenâ an der Technischen UniversitĂ€t Darmstadt
Die Floristisch-soziologische Arbeitsgemeinschaft hat bisher - auĂer im Rahmen von Arbeitskreisen - keine Tagungsveranstaltung angeboten, die unabhĂ€ngig von den Jahrestagungen mit Exkursion bestimmte Themen aufgreift und diskutiert. Auf Vorschlag von unserem jetzigen Ehrenmitglied Prof. Dr. E.-G. Mahn (Halle/Saale) und von Dr. P. Thomas (HatzenbĂŒhl) wurde bereits auf der Mitgliederversammlung in Erlangen 2005 auf den Bedarf zusĂ€tzlicher AktivitĂ€ten der Arbeitsgemeinschaft, z. B. zu praxisrelevanten Fragen, hingewiesen.
An dem 1. Workshop in Darmstadt nahmen etwa 70 Mitglieder und Interessenten teil. Die insgesamt 14 VortrĂ€ge und 16 Poster-Demonstrationen deckten eine breite Palette angewandter Fragestellungen ab. Eine Kooperation mit der âArbeitsgemeinschaft Forstliche Standorts- und Vegetationskundeâ, die auf der Mitgliederversammlung 2006 beschlossen wurde (Tuexenia 27: WALENTOWSKI et al., Waldoekologie online 3: 102) spiegelte sich bereits bei diesem Workshop mit insgesamt vier waldökologischen VortrĂ€gen und drei Postern wider
Wild bees (Anthophila) of Macaronesia: Aspects of biogeography, species diversity, evolutionary patterns and taxonomic problems.
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