27 research outputs found

    Interacting effects of forest edge, tree diversity and forest stratum on the diversity of plants and arthropods in Germany’s largest deciduous forest

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    Die fortschreitende Fragmentierung von WĂ€ldern ist eine der Hauptursachen fĂŒr den Verlust von BiodiversitĂ€t weltweit. Mit zunehmender Fragmentierung steigt der Anteil an Waldrandzonen, in denen die Eigenschaften eines Waldes stark verĂ€ndert sein können. Wie stark diese Randeffekte ein Fragment beeinflussen, kann von der Habitatstruktur abhĂ€ngen. Die Habitatstruktur ist wiederum maßgeblich durch die Baumartenzusammensetzung beeinflusst. Die vorliegende Arbeit untersucht zum ersten Mal gleichzeitig die EinflĂŒsse von Randeffekten und Baumartenvielfalt und deren mögliche Interaktionen auf Krautschichtvegetation und Arthropoden. Die Untersuchungen hierzu wurden im Nationalpark Hainich, Deutschlands grĂ¶ĂŸtem zusammenhĂ€ngenden Laubwaldgebiet, durchgefĂŒhrt. DafĂŒr wurden 12 Transekte angelegt, die vom Waldrand bis zu 500 m in das Waldesinnere hineinreichten. Sechs Transekte in baumartenarmen Waldstandorten mit einem hohen Buchenanteil (Fagus sylvatica L.) und weitere sechs in baumartenreichen Waldstandorten mit einem niedrigen Buchenanteil. Baumartenreiche Standorte wiesen bis zu neun Baumarten auf, wie z.B. Eiche, Esche, Linde und Ahorn. Entlang der Transekte wurden die Krautschichtvegetation und die Arthopodengemeinschaften untersucht. Im ersten Manuskript (Kapitel 2 dieser Arbeit) wurde die Krautschichtvegetation entlang des Rand-Innen-Gradienten aufgenommen. Eine Interaktion zwischen Randeffekten und Baumartenvielfalt beeinflusste den Pflanzenartenreichtum. In Waldbereichen mit hoher Baumartenvielfalt blieb die Artenzahl der Krautschicht vom Rand bis ins Waldesinnere konstant, wohingegen sie in baumartenarmen Bereichen stark abfiel. Die Krautschicht war somit in baumartenreichen Waldstandorten im Waldesinneren höher. Der Anteil an Waldspezialistenarten nahm mit zunehmender Entfernung vom Waldrand zur Mitte zu. Parallel dazu nahm der Anteil an Waldgeneralistenarten ab. Die Dominanz der Waldspezialisten war in buchendominierten Standorten stĂ€rker ausgeprĂ€gt, als in baumartenreichen. Auch die Artenzusammensetzung der Krautschicht wurde von der Distanz zum Waldrand und der Baumartenvielfalt beeinflusst. Sie wies in baumartenreichen Standorten und mit zunehmender NĂ€he zum Rand eine hohe VariabilitĂ€t auf. Die Baumartenvielfalt steuerte die Dicke der Streuschicht, die unter allen untersuchten Umweltfaktoren den grĂ¶ĂŸten Einfluss auf die DiversitĂ€t der Krautschicht hatte. Im zweiten Manuskript (Kapitel 3 dieser Arbeit) wurden bodenlebende Arthropoden (LaufkĂ€fer, KurzflĂŒgelkĂ€fer und Spinnen) untersucht. Die Reaktion der Gesamtartenzahl auf Baumartenvielfalt und Entfernung zum Waldrand war je nach Taxon unterschiedlich. Allerdings zeigten sich ĂŒbereinstimmende Muster, nachdem die Arten hinsichtlich ihrer HabitataffinitĂ€t und KörpergrĂ¶ĂŸe in Gruppen eingeteilt worden waren. Über alle Taxa hinweg wurde die Anzahl der Waldarten weder von der Baumartenvielfalt noch von der RandnĂ€he nennenswert beeinflusst und die KörpergrĂ¶ĂŸe der Waldarten spielte keine Rolle. Allerdings reagierten einzelne Waldarten positiv auf eine erhöhte Baumartenvielfalt, wĂ€hrend andere davon negativ beeinflusst waren. Die Artenzahl der Habitatgeneralisten nahm vom Waldrand zur Waldmitte hin stark ab. Dieser Effekt wurde jedoch, außer bei den Spinnen, durch eine höhere Baumartenvielfalt abgeschwĂ€cht. Die Artenzahl der Habitatgeneralisten, insbesondere der kleinen Arten, reagierte positiv auf eine erhöhte Baumartenvielfalt im Waldesinneren. Die beobachteten Effekte sind höchstwahrscheinlich das Resultat von durch Baumartenvielfalt und RandnĂ€he verĂ€nderten Umweltfaktoren und einer erhöhten HabitatheterogenitĂ€t am Waldboden. Im dritten Manuskript (Kapitel 4 dieser Arbeit) wurde untersucht, ob sich Rand- und BaumartendiversitĂ€tseffekte zwischen verschiedenen Straten unterscheiden. Hierzu wurden entlang von zehn Transekten sowohl im Kronenraum als auch unmittelbar ĂŒber dem Boden Kreuzfensterfallen installiert. In einem Zeitraum von sieben Monaten (April bis November 2012) wurde dadurch die fliegende KĂ€ferfauna erfasst. Randeffekte auf KĂ€fer wurden bis zu einer Distanz von 500 m vom Waldrand hin nachgewiesen. Im Kronenraum waren die Randeffekte schwĂ€cher ausgeprĂ€gt als im Unterholz, vermutlich durch eine höhere „randĂ€hnliche“ mikroklimatische VariabilitĂ€t im Kronenraum. Die Gesamtartenzahl der KĂ€fer nahm mit zunehmender Distanz zum Waldrand ab. Dieses Muster wurde vor allem durch die Habitatgeneralisten getrieben, wohingegen die Artenzahl der Waldarten und der xylobionten Arten kaum auf die RandnĂ€he reagierten. Eine Beeinflussung des Randeffekts durch Baumartenvielfalt konnte nicht gezeigt werden. Habitatgeneralisten und nicht-xylobionte Arten dominierten die KĂ€fergemeinschaft im Unterholz. Im Kronenraum wurden die höchsten Artenzahlen von Waldarten und xylobionten Arten nachgewiesen. BaumartendiversitĂ€t wirkte sich ĂŒber alle Straten und ökologischen Gruppen positiv auf die Artenvielfalt der KĂ€fer aus. Besonders ausgeprĂ€gt war dieser Effekt im Kronenraum. Die Haupteinflussfaktoren, die den KĂ€ferartenreichtum steuerten, unterschieden sich also zwischen den Straten. So waren im Kronenraum Baumartenvielfalt, die Totholzmenge und zu einem geringen Teil der Kronenschluss die entscheidenden Faktoren. Im Unterholz hingegen war der Einfluss der Baumartenvielfalt geringer und die Distanz zum Waldrand und der Kronenschluss besonders wichtig. Insgesamt waren die Effekte von Baumartenvielfalt im Unterholz indirekter und im Kronenraum direkter. Um Konsequenzen von Waldfragmentierung umfangreich zu verstehen, ist es nicht nur notwendig den Einfluss von Randeffekten, Baumartenvielfalt und Straten zu berĂŒcksichtigen, sondern auch die Eigenschaften (z. B. KörpergrĂ¶ĂŸe) und die HabitataffinitĂ€t der beobachteten Arten. Diese Arbeit zeigt, dass eine erhöhte Baumartenvielfalt in zentraleuropĂ€ischen WĂ€ldern zum Erhalt der BiodiversitĂ€t von Pflanzen und Arthropoden beitragen kann. Das allein ist jedoch nicht ausreichend, da auch gezeigt wurde, dass einzelne Arten buchendominierte WĂ€lder bevorzugen und es Unterschiede in der Artenzusammensetzung zwischen den verschiedenen BaumartendiversitĂ€tsstufen gibt. Dies hebt die Bedeutung des Erhalts alter BuchenwĂ€lder, verankert in den UNESCO-WelterbeflĂ€chen „BuchenurwĂ€lder in den Karpaten und alte BuchenwĂ€lder in Deutschland“, als besondere Schutzaufgabe hervor

    Association of telomerase activity with radio- and chemosensitivity of neuroblastomas

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    <p>Abstract</p> <p>Background</p> <p>Telomerase activity compensates shortening of telomeres during cell division and enables cancer cells to escape senescent processes. It is also supposed, that telomerase is associated with radio- and chemoresistance. In the here described study we systematically investigated the influence of telomerase activity (TA) and telomere length on the outcome of radio- and chemotherapy in neuroblastoma.</p> <p>Methods</p> <p>We studied the effects on dominant negative (DN) mutant, wild type (WT) of the telomerase catalytic unit (hTERT) using neuroblastoma cell lines. The cells were irradiated with <sup>60</sup>Co and treated with doxorubicin, etoposide, cisplatin and ifosfamide, respectively. Viability was determined by MTS/MTT-test and the GI<sub>50 </sub>was calculated. Telomere length was measured by southernblot analysis and TA by Trap-Assay.</p> <p>Results</p> <p>Compared to the hTERT expressing cells the dominant negative cells showed increased radiosensitivity with decreased telomere length. Independent of telomere length, telomerase negative cells are significantly more sensitive to irradiation. The effect of TA knock-down or overexpression on chemosensitivity were dependent on TA, the anticancer drug, and the chemosensitivity of the maternal cell line.</p> <p>Conclusions</p> <p>Our results supported the concept of telomerase inhibition as an antiproliferative treatment approach in neuroblastomas. Telomerase inhibition increases the outcome of radiotherapy while in combination with chemotherapy the outcome depends on drug- and cell line and can be additive/synergistic or antagonistic. High telomerase activity is one distinct cancer stem cell feature and the here described cellular constructs in combination with stem cell markers like CD133, Aldehyddehydrogenase-1 (ALDH-1) or Side population (SP) may help to investigate the impact of telomerase activity on cancer stem cell survival under therapy.</p

    Platelet Serotonin Aggravates Myocardial Ischemia/Reperfusion Injury via Neutrophil Degranulation

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    Background: Platelets store large amounts of serotonin that they release during thrombus formation or acute inflammation. This facilitates hemostasis and modulates the inflammatory response. Methods: Infarct size, heart function, and inflammatory cell composition were analyzed in mouse models of myocardial reperfusion injury with genetic and pharmacological depletion of platelet serotonin. These studies were complemented by in vitro serotonin stimulation assays of platelets and leukocytes in mice and men, and by measuring plasma serotonin levels and leukocyte activation in patients with acute coronary syndrome. Results: Platelet-derived serotonin induced neutrophil degranulation with release of myeloperoxidase and hydrogen peroxide (H2O2) and increased expression of membrane-bound leukocyte adhesion molecule CD11b, leading to enhanced inflammation in the infarct area and reduced myocardial salvage. In patients hospitalized with acute coronary syndrome, plasmatic serotonin levels correlated with CD11b expression on neutrophils and myeloperoxidase plasma levels. Long-term serotonin reuptake inhibition - reported to protect patients with depression from cardiovascular events - resulted in the depletion of platelet serotonin stores in mice. These mice displayed a reduction in neutrophil degranulation and preserved cardiac function. In line, patients with depression using serotonin reuptake inhibition, presented with suppressed levels of CD11b surface expression on neutrophils and lower myeloperoxidase levels in blood. Conclusions: Taken together, we identify serotonin as a potent therapeutic target in neutrophil-dependent thromboinflammation during myocardial reperfusion injury.Fil: Mauler, Maximilian. No especifíca;Fil: Herr, Nadine. No especifíca;Fil: Schoenichen, Claudia. No especifíca;Fil: Witsch, Thilo. No especifíca;Fil: Marchini, Timoteo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: HÀrdtner, Carmen. No especifíca;Fil: Koentges, Christoph. No especifíca;Fil: Kienle, Korbinian. Max Planck Institute Of Immunobiology And Epigenetics; AlemaniaFil: Ollivier, Véronique. Inserm; FranciaFil: Schell, Maximilian. No especifíca;Fil: Dorner, Ludwig. No especifíca;Fil: Wippel, Christopher. No especifíca;Fil: Stallmann, Daniela. No especifíca;Fil: Normann, Claus. No especifíca;Fil: Bugger, Heiko. No especifíca;Fil: Walther, Paul. Universitat Ulm; AlemaniaFil: Wolf, Dennis. La Jolla Institute for Allergy and Immunology; Estados UnidosFil: Ahrens, Ingo. No especifíca;Fil: LÀmmermann, Tim. Max Planck Institute Of Immunobiology And Epigenetics; AlemaniaFil: Ho-Tin-Noé, Benoßt. Inserm; FranciaFil: Ley, Klaus. La Jolla Institute for Allergy and Immunology; Estados UnidosFil: Bode, Christoph. No especifíca;Fil: Hilgendorf, Ingo. No especifíca;Fil: Duerschmied, Daniel. No especifíca

    A metacognitive model of procrastination

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    BACKGROUND: procrastination refers to the delay or postponement of task or decision-making initiation or completion and is often conceptualised as a failure of self-regulation. Recent research has suggested that metacognitions play a role in procrastination and that unintentional procrastination (UP), as opposed to intentional procrastination (IP), may be the most problematic form of this behaviour. We aimed to test a metacognitive model of procrastination that was grounded in the Self-Regulatory Executive Function model. METHODS: a convenience sample of 400 participants were recruited and completed (at least partially) a battery of online questionnaires that measured IP and UP, metacognitions about procrastination, depression, and Cognitive Attentional Syndrome (CAS) configurations. Initially, we tested series of hypotheses to establish the relationships between the experimental variables and to test whether CAS configurations would independently predict UP when controlling for age, depression, IP, metacognitions about procrastination, and whether an individual reported that they had been diagnosed with a psychiatric disorder. RESULTS: CAS configurations, depression, and metacognitions independently predicted UP. Additionally, path analysis revealed that the study data was an excellent fit to the proposed metacognitive model of procrastination. LIMITATIONS: the study is cross-sectional. CONCLUSIONS: the metacognitive model of procrastination presented in this paper can be used to generate novel interventions to treat this problematic behaviour

    Dialect, interaction and class positioning at school: from deficit to difference to repertoire.

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    Sociolinguists have been fighting dialect prejudice since the 1960s, but deficit views of non-standard English are regaining currency in educational discourse. In this paper I argue that the traditional sociolinguistic response – stressing dialect systematicity and tolerance of ‘difference’ – may no longer be effective by questioning a key assumption that both deficit and difference approaches share, namely that there exist discrete varieties of English. Based on an empirical study of the language of working-class children in north-east England, I demonstrate that non-standard dialects of English do not have a discrete system of grammar that is isolated from other varieties; rather local dialect forms interact with a range of semiotic resources (including standard forms) within speakers’ repertoires. Interactional analyses of the children’s spontaneous speech highlight this hybridity, as well as the social meanings behind the linguistic choices children make. I conclude by addressing educational responses to non-standard dialect in the classroom, suggesting that it is not the presence or absence of non-standard forms in children’s speech that raises educational issues; rather, educational responses which problematise non-standard voices risk marginalising working-class speech, and may contribute to the alienation of working-class children, or significant groups of them, within the school system

    Comparing cropland net primary production estimates frominventory, a satellite-based model, and a process-based model in theMidwest of the United States

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    Accurately quantifying the spatial and temporal variability of net primary production (NPP) for crop-lands is essential to understand regional cropland carbon dynamics. We compared three NPP estimates for croplands in the Midwestern United States: inventory-based estimates using crop yield data from the U.S. Department of Agriculture (USDA) National Agricultural Statistics Service (NASS); estimates from the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) NPP product; and estimates from the General Ensemble biogeochemical Modeling System (GEMS) process-based model. The three methods estimated mean NPP in the range of 469–687 g C m−2yr−1and total NPP in the range of318–490 Tg C yr−1for croplands in the Midwest in 2007 and 2008. The NPP estimates from crop yield data and the GEMS model showed the mean NPP for croplands was over 650 g C m−2yr−1while the MODISNPP product estimated the mean NPP was less than 500 g C m−2yr−1. MODIS NPP also showed very different spatial variability of the cropland NPP from the other two methods. We found these differences were mainly caused by the difference in the land cover data and the crop specific information used in the methods. Our study demonstrated that the detailed mapping of the temporal and spatial change of crop species is critical for estimating the spatial and temporal variability of cropland NPP. We suggest that high resolution land cover data with species–specific crop information should be used in satellite-based and process-based models to improve carbon estimates for croplands

    Consumers in a Sustainable Food Supply Chain (COSUS): Understanding Consumer Behavior to Encourage Food Waste Reduction

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    Consumers are directly and indirectly responsible for a significant fraction of food waste which, for a large part, could be avoided if they were willing to accept food that is suboptimal, i.e., food that deviates in sensory characteristics (odd shape, discoloration), or that has a best-before date which is approaching or has passed, but that is still perfectly fine to eat. The choice to accept or discard suboptimal food is taken either before or after purchase (hence, in the retail store or in the household). The aim of the European research project COSUS (Consumers in a sustainable food supply chain) was to increase consumer acceptance of suboptimal food, before and after purchase, by implementing targeted strategies that are based on consumer insights, and that are feasible for and acceptable by the food sector. To reach this aim, different methodological approaches were applied to analyze this issue, to experiment with different aspects, and to test the resulting interventions. Each of these approaches was undertaken by competent consortium partners from Denmark, Germany, Norway, Sweden and The Netherlands. The project finally provides validated strategies to promote the distribution and consumption of suboptimal foods, thereby improving resource efficiency in the food chain and contributing to a more sustainable food supply

    Evaluation of different biomarkers to predict individual radiosensitivity in an inter-laboratory comparison--lessons for future studies.

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    Radiotherapy is a powerful cure for several types of solid tumours, but its application is often limited because of severe side effects in individual patients. With the aim to find biomarkers capable of predicting normal tissue side reactions we analysed the radiation responses of cells from individual head and neck tumour and breast cancer patients of different clinical radiosensitivity in a multicentric study. Multiple parameters of cellular radiosensitivity were analysed in coded samples of peripheral blood lymphocytes (PBLs) and derived lymphoblastoid cell lines (LCLs) from 15 clinical radio-hypersensitive tumour patients and compared to age- and sex-matched non-radiosensitive patient controls and 15 lymphoblastoid cell lines from age- and sex- matched healthy controls of the KORA study. Experimental parameters included ionizing radiation (IR)-induced cell death (AnnexinV), induction and repair of DNA strand breaks (Comet assay), induction of yH2AX foci (as a result of DNA double strand breaks), and whole genome expression analyses. Considerable inter-individual differences in IR-induced DNA strand breaks and their repair and/or cell death could be detected in primary and immortalised cells with the applied assays. The group of clinically radiosensitive patients was not unequivocally distinguishable from normal responding patients nor were individual overreacting patients in the test system unambiguously identified by two different laboratories. Thus, the in vitro test systems investigated here seem not to be appropriate for a general prediction of clinical reactions during or after radiotherapy due to the experimental variability compared to the small effect of radiation sensitivity. Genome-wide expression analysis however revealed a set of 67 marker genes which were differentially induced 6 h after in vitro-irradiation in lymphocytes from radio-hypersensitive and non-radiosensitive patients. These results warrant future validation in larger cohorts in order to determine parameters potentially predictive for clinical radiosensitivity
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