89 research outputs found

    Modeling gap dynamics, succession, and disturbance regimes of mangrove forests: MANDY (MANgrove DYnamics)

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    Despite their important ecosystem benefits for terrestrial and marine flora and fauna and the human livelihood mangrove forests suffer a high loss rate mainly due to human activity. Aside from these impacts, natural forest disturbances exist more commonly in mangroves compared to other forests as a direct consequence of their exposed coastal location. Within this thesis I investigate the influence of natural disturbance regimes on the mangrove forest dynamics focusing in particular on the ecological role of disturbances, disturbance patterns, forest structure, succession behavior and long-term vulnerability evaluation. The study areas were set in the Indian River Lagoon in Florida (USA) and in Can Gio an UNESCO Biosphere Reserve (Vietnam). In addition, theoretical simulation studies were carried out to complement the field studies. Thereby, in our study at the Indian River Lagoon site I investigated the ecosystem response to hurricane events of an artificially impounded mangrove forest. In Can Gio, the suitability of lightning strike – caused gaps for setting a homogenous plantation into more natural-like state according to species composition and forest structure was analyzed. Finally, a theoretical simulation study was carried out to compare lightning strike and hurricane events regarding their homogenization and heterogenization effects on the spatio-temporal forest structure. The findings of the field study in the Indian River Lagoon indicate that hurricane events had a severe impact on forest areas in higher successional stages by creating open patches, whereas areas in lower successional stages remained largely undisturbed. Furthermore, the impoundment determines the species selection of the post-hurricane succession by favoring flooding-tolerant species. However, regeneration was found to be impaired by the artificially high inundation regime at some disturbed patches. The lightning-strike disturbances enhance the species composition in the monospecific plantation in Can Gio by providing a sufficient light regime for entering seeds to establish. In addition, lightning-strike gaps increased the plantation structure complexity. Regenerating lightning-strike gaps remained as “green islands” within windthrow sites in the plantation due to their low stature and provided seeds for surrounding disturbed areas thereby accelerating their recolonization. The results of the simulation analysis of a theoretical landscape showed that in the simulated highly complex natural mature forests all disturbance regimes entail homogenization on the spatial structure compared to an undisturbed scenario. The hurricane scenario showed an increased temporal variation of the forest dynamics whereas lightning-strike gaps were not able to contribute to additional heterogeneity in the simulated area, despite of having the same tree mortality probability during disturbances. The interaction of the large-scale impoundment in the Indian River Lagoon and medium-sized hurricane events is characterized by partially impeded post-hurricane regeneration. In contrast, small-scaled lightning strikes influenced the regeneration of medium-sized windthrow sites positively within the homogenous plantation. We therefore suggest management activities aimed at creating small clearances within the plantation in Can Gio to simulate additional small-scale disturbances in order to facilitate heterogenization of the plantation structure. Natural disturbances are found to be able to enhance the species diversity and the interactions of ecological processes. In particular, where sustainable management strategies focused on maintaining ecosystem services especially in restored sites or plantations act as a supportive part. Natural disturbances are an integral component of mangrove forests and fulfill specific ecological functions. However, our findings indicate that these disturbances, on top of altered environmental conditions associated with climate change and direct human impacts, might jeopardize the natural development in unnatural forest structures as on plantations or restored sites. This thesis gives an extensive overview about the effect of various disturbances in different mangrove forest systems, including semi-natural forests and strongly modified plantations, on species composition and forest structure. Field studies and simulation analyses contribute in equal parts to the results of the thesis

    C-Reactive Protein Causes Blood Pressure Drop in Rabbits and Induces Intracellular Calcium Signaling

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    Systemic diseases characterized by elevated levels of C-reactive protein (CRP), such as sepsis or systemic inflammatory response syndrome, are usually associated with hardly controllable haemodynamic instability. We therefore investigated whether CRP itself influences blood pressure and heart rate. Immediately after intravenous injection of purified human CRP (3.5 mg CRP/kg body weight) into anesthetized rabbits, blood pressure dropped critically in all animals, while control animals injected with bovine serum albumin showed no response. Heart rate did not change in either group. Approaching this impact on a cellular level, we investigated the effect of CRP in cell lines expressing adrenoceptors (CHO-α1A and DU-145). CRP caused a Ca(2+)signaling being dependent on the CRP dose. After complete activation of the adrenoceptors by agonists, CRP caused additional intracellular Ca(2+)mobilization. We assume that CRP interacts with hitherto unknown structures on the surface of vital cells and thus interferes with the desensitization of adrenoceptors

    Physical activity and health promotion for nursing staff in elderly care: a study protocol for a randomised controlled trial

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    Introduction Nursing staff is burdened by high workload and stress. Furthermore, heavy lifting, as well as transferring nursing home residents, cause lumbar tissue damage and back pain. Exercise intervention studies to reduce work-related problems are rare and the evidence for efficacy of studies among nurses is limited. Studies including targeted analysis of requirements are necessary to generate effective recommendations and tailored interventions for health promotion programmes. The purpose of this multicentred intervention study is to identify work-related problems, to implement health promotion programmes and to evaluate their effectiveness. Methods and analysis A randomised controlled trial will be conducted, including a total of 48 nursing home facilities in eight regions of Germany with an estimated sample size of 700 nurses. Standardised ergonomics and posture training (10 weeks, once a week for 20–30 min) and subsequently, back-fitness training (12 weeks, once a week for 45–60 min) will be administered. Following the implementation of standardised health promotion programmes, further demand-oriented interventions can be implemented. The perceived exposure to work-related demands, work-related pain in different parts of the body, health-related quality of life, perceived stress, work-related patterns of behaviour and experience, presentism behaviour, work environment as well as general needs and barriers to health promotion, will be assessed at baseline (pre-test), at 10 weeks (post-test, after ergonomics training), at 22 weeks (post-test, after back-fitness training) and at 34 weeks of the programme (follow-up). Ethics and dissemination The study was reviewed and approved by the local ethics committee of the University of Hamburg (AZ: 2018_168). The results of the study will be published in open-access and international journals. Furthermore, the results will be presented in the participating nursing homes and at national and international conferences

    Variabilidade espaço-temporal da precipitação e temperatura de superfĂ­cie na mesorregiĂŁo sul do amazonas durante a ocorrĂȘncia de ENOS

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    Impacts of El Niño – Southern Oscillation (ENSO) climatic phenomena in the southern mesoregion of the Amazon is still poorly understood. Thus, the objective of this study was to analyze the impacts of ENSO of moderate and strong categories on precipitation (ppt) and surface temperature (ts) in the southern mesoregion of Amazonas. The research was carried out with ppt data obtained by the product TRMM_3B43 and ts of the product MOD11C3 in the municipalities of ApuĂ­, Boca do Acre, Canutama, HumaitĂĄ, LĂĄbrea, ManicorĂ© and Novo AripuanĂŁ. The Niño Indices were obtained from the National Oceanic Atmospheric Administration. Ts was organized into averages and ppt in seasonal totals from 1998 to 2019, to obtain its provisional climatological normal in the dry and wet seasons. The results showed that ENSO significantly influenced the pattern of ppt and ts in the southern mesoregion of Amazonas. El Niño (EN) had more impact on changing the pattern of ppt and ts than La Niña (LN). The largest reductions in ppt and increases in Ts occurred in the EN periods of 1998/01 and 2015/16, while the occurrence of LN decreased the ppt more expressively in the periods of 2007/08 and 2011/12.Os impactos dos fenĂŽmenos climĂĄticos El Niño – Oscilação Sul (ENOS) na mesorregiĂŁo sul da amazĂŽnia ainda sĂŁo pouco conhecidos. Este estudo teve como objetivo analisar os impactos do ENOS de categorias moderada e forte sobre a precipitação e temperatura de superfĂ­cie da mesorregiĂŁo sul do amazonas. A pesquisa foi realizada em sete municĂ­pios da mesorregiĂŁo sul do Amazonas: ApuĂ­, Boca do Acre, Canutama, HumaitĂĄ, LĂĄbrea, ManicorĂ© e Novo AripuanĂŁ. As precipitaçÔes foram obtidas pelo sensor trmm_3b43, enquanto as temperaturas da superfĂ­cie foram obtidas pelo produto mod11c3. Os Ă­ndices oceĂąnicos niño foram acessados diretamente no portal National Oceanic Atmospheric Administration. Foram calculadas as mĂ©dias aritmĂ©ticas e totais sazonais para o perĂ­odo compreendido neste estudo (1998 a 2019), no intuito de obter as normais climatolĂłgicas provisĂłrias de temperatura da superfĂ­cie e precipitação, respectivamente, nos perĂ­odos seco e chuvoso. Os resultados demonstraram que o ENOS, em ambas as categorias analisadas, exerceu influĂȘncia significativa sobre as variĂĄveis abordadas no estudo, visto que os comportamentos dessas foram alterados durante a ocorrĂȘncia do evento. Os impactos do El Niño sobre a precipitação e temperatura de superfĂ­cie foram maiores que os do La Niña. Os perĂ­odos de 1998/01 e 2015/16 sofreram as maiores reduçÔes de precipitação e aumento de temperatura de superfĂ­cie. Durante a ocorrĂȘncia do la niña, as precipitaçÔes nos perĂ­odos de 2007/08 e 2011/12 apresentaram anomalias negativas mais expressivas. Todavia, as temperaturas de superfĂ­cie nĂŁo foram tĂŁo afetadas pelo evento

    Functional electrical stimulation driven by a brain–computer interface in acute and subacute stroke patients impacts beta power and long-range temporal correlation

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    Functional electrical stimulation (FES) is a standard rehabilitation approach applied by therapists to aid motor recovery in a paretic limb post-stroke. Information pertaining to the timing of a movement attempt can be obtained from changes in the power of oscillatory electrophysiological activity in motor cortical regions, derived from scalp electroencephalographic (EEG) recordings. The use of a brain–computer interface (BCI), to enable delivery of FES within a tight temporal window with a movement attempt detected in scalp EEG, is associated with greater motor recovery than conventional FES application in patients in the chronic phase post-stroke. We hypothesized that the heightened neural plasticity early post-stroke could further enhance motor recovery and that motor improvements would be accompanied by changes in the motor cortical sensorimotor rhythm after compared with before treatment. Here we assessed clinical outcome and changes in the sensorimotor rhythm in patients following subcortical stroke affecting the non-dominant hemisphere from a study comparing timing of FES delivery using a BCI, with a Sham group, receiving FES with no such temporal relationship. The BCI group showed greater clinical improvement following the treatment, particularly early post-stroke, and a greater decrease in beta oscillatory power and long-range temporal correlation over contralateral (ipsilesional) motor cortex. The electrophysiological changes are consistent with a reduction in compensatory processes and a transition towards a subcritical state when movement is triggered at the time of movement detection based on motor cortical oscillations

    26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15–20 July 2017

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    This work was produced as part of the activities of FAPESP Research,\ud Disseminations and Innovation Center for Neuromathematics (grant\ud 2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud supported by a CNPq fellowship (grant 306251/2014-0)

    Modeling gap dynamics, succession, and disturbance regimes of mangrove forests: MANDY (MANgrove DYnamics)

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    Despite their important ecosystem benefits for terrestrial and marine flora and fauna and the human livelihood mangrove forests suffer a high loss rate mainly due to human activity. Aside from these impacts, natural forest disturbances exist more commonly in mangroves compared to other forests as a direct consequence of their exposed coastal location. Within this thesis I investigate the influence of natural disturbance regimes on the mangrove forest dynamics focusing in particular on the ecological role of disturbances, disturbance patterns, forest structure, succession behavior and long-term vulnerability evaluation. The study areas were set in the Indian River Lagoon in Florida (USA) and in Can Gio an UNESCO Biosphere Reserve (Vietnam). In addition, theoretical simulation studies were carried out to complement the field studies. Thereby, in our study at the Indian River Lagoon site I investigated the ecosystem response to hurricane events of an artificially impounded mangrove forest. In Can Gio, the suitability of lightning strike – caused gaps for setting a homogenous plantation into more natural-like state according to species composition and forest structure was analyzed. Finally, a theoretical simulation study was carried out to compare lightning strike and hurricane events regarding their homogenization and heterogenization effects on the spatio-temporal forest structure. The findings of the field study in the Indian River Lagoon indicate that hurricane events had a severe impact on forest areas in higher successional stages by creating open patches, whereas areas in lower successional stages remained largely undisturbed. Furthermore, the impoundment determines the species selection of the post-hurricane succession by favoring flooding-tolerant species. However, regeneration was found to be impaired by the artificially high inundation regime at some disturbed patches. The lightning-strike disturbances enhance the species composition in the monospecific plantation in Can Gio by providing a sufficient light regime for entering seeds to establish. In addition, lightning-strike gaps increased the plantation structure complexity. Regenerating lightning-strike gaps remained as “green islands” within windthrow sites in the plantation due to their low stature and provided seeds for surrounding disturbed areas thereby accelerating their recolonization. The results of the simulation analysis of a theoretical landscape showed that in the simulated highly complex natural mature forests all disturbance regimes entail homogenization on the spatial structure compared to an undisturbed scenario. The hurricane scenario showed an increased temporal variation of the forest dynamics whereas lightning-strike gaps were not able to contribute to additional heterogeneity in the simulated area, despite of having the same tree mortality probability during disturbances. The interaction of the large-scale impoundment in the Indian River Lagoon and medium-sized hurricane events is characterized by partially impeded post-hurricane regeneration. In contrast, small-scaled lightning strikes influenced the regeneration of medium-sized windthrow sites positively within the homogenous plantation. We therefore suggest management activities aimed at creating small clearances within the plantation in Can Gio to simulate additional small-scale disturbances in order to facilitate heterogenization of the plantation structure. Natural disturbances are found to be able to enhance the species diversity and the interactions of ecological processes. In particular, where sustainable management strategies focused on maintaining ecosystem services especially in restored sites or plantations act as a supportive part. Natural disturbances are an integral component of mangrove forests and fulfill specific ecological functions. However, our findings indicate that these disturbances, on top of altered environmental conditions associated with climate change and direct human impacts, might jeopardize the natural development in unnatural forest structures as on plantations or restored sites. This thesis gives an extensive overview about the effect of various disturbances in different mangrove forest systems, including semi-natural forests and strongly modified plantations, on species composition and forest structure. Field studies and simulation analyses contribute in equal parts to the results of the thesis

    Modeling gap dynamics, succession, and disturbance regimes of mangrove forests: MANDY (MANgrove DYnamics)

    Get PDF
    Despite their important ecosystem benefits for terrestrial and marine flora and fauna and the human livelihood mangrove forests suffer a high loss rate mainly due to human activity. Aside from these impacts, natural forest disturbances exist more commonly in mangroves compared to other forests as a direct consequence of their exposed coastal location. Within this thesis I investigate the influence of natural disturbance regimes on the mangrove forest dynamics focusing in particular on the ecological role of disturbances, disturbance patterns, forest structure, succession behavior and long-term vulnerability evaluation. The study areas were set in the Indian River Lagoon in Florida (USA) and in Can Gio an UNESCO Biosphere Reserve (Vietnam). In addition, theoretical simulation studies were carried out to complement the field studies. Thereby, in our study at the Indian River Lagoon site I investigated the ecosystem response to hurricane events of an artificially impounded mangrove forest. In Can Gio, the suitability of lightning strike – caused gaps for setting a homogenous plantation into more natural-like state according to species composition and forest structure was analyzed. Finally, a theoretical simulation study was carried out to compare lightning strike and hurricane events regarding their homogenization and heterogenization effects on the spatio-temporal forest structure. The findings of the field study in the Indian River Lagoon indicate that hurricane events had a severe impact on forest areas in higher successional stages by creating open patches, whereas areas in lower successional stages remained largely undisturbed. Furthermore, the impoundment determines the species selection of the post-hurricane succession by favoring flooding-tolerant species. However, regeneration was found to be impaired by the artificially high inundation regime at some disturbed patches. The lightning-strike disturbances enhance the species composition in the monospecific plantation in Can Gio by providing a sufficient light regime for entering seeds to establish. In addition, lightning-strike gaps increased the plantation structure complexity. Regenerating lightning-strike gaps remained as “green islands” within windthrow sites in the plantation due to their low stature and provided seeds for surrounding disturbed areas thereby accelerating their recolonization. The results of the simulation analysis of a theoretical landscape showed that in the simulated highly complex natural mature forests all disturbance regimes entail homogenization on the spatial structure compared to an undisturbed scenario. The hurricane scenario showed an increased temporal variation of the forest dynamics whereas lightning-strike gaps were not able to contribute to additional heterogeneity in the simulated area, despite of having the same tree mortality probability during disturbances. The interaction of the large-scale impoundment in the Indian River Lagoon and medium-sized hurricane events is characterized by partially impeded post-hurricane regeneration. In contrast, small-scaled lightning strikes influenced the regeneration of medium-sized windthrow sites positively within the homogenous plantation. We therefore suggest management activities aimed at creating small clearances within the plantation in Can Gio to simulate additional small-scale disturbances in order to facilitate heterogenization of the plantation structure. Natural disturbances are found to be able to enhance the species diversity and the interactions of ecological processes. In particular, where sustainable management strategies focused on maintaining ecosystem services especially in restored sites or plantations act as a supportive part. Natural disturbances are an integral component of mangrove forests and fulfill specific ecological functions. However, our findings indicate that these disturbances, on top of altered environmental conditions associated with climate change and direct human impacts, might jeopardize the natural development in unnatural forest structures as on plantations or restored sites. This thesis gives an extensive overview about the effect of various disturbances in different mangrove forest systems, including semi-natural forests and strongly modified plantations, on species composition and forest structure. Field studies and simulation analyses contribute in equal parts to the results of the thesis
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