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851.
Janusz Bogdan Falinski 《Plant Ecology》1978,38(3):175-183
Summary The paper reports results of a long-term (1964–1974) investigation on permanent study sites in natural forest ecosystems of the Tilio-Carpinetum and the Pino-Quercetum in the Bialowieza Forest. The influence of decaying logs and root craters was investigated. It was found that the main causes of uprooting were the spring and autumn winds. Wind direction and the position of logs lying on the ground are correlated. Picea is most susceptible to uprooting by winds. Almost one half of the trees of this species are alive at the moment of uprooting.By mapping changes in the distribution of uprooted trees on a permanent area in time, a balance of the change over in a 10-year period was determined. It appeared that the decomposition is slower than accumulation. From this, it was concluded that the stand is in a phase of natural thinning. In the study site, compartments were disinguished with various degrees of change in the number of uprooted trees, and the consequences of differentiation and constant transformation of the biotope and biocenosis by the occurrence of uprooted trees and by their decay are described.Nomenclature of species follows Flora Europaea.Contribution to the Symposium of the Working Group for Succession Research on Permanent Plots, held at Yerseke, the Netherlands, October 1975. 相似文献
852.
Mahmud Bani-Yaghoub Roger G Tremblay Abdellah Ajji Munyao Nzau Sandhya Gangaraju David Chitty Bogdan Zurakowski Marianna Sikorska 《Biochimie et biologie cellulaire》2008,86(5):361-369
Every year thousands of people suffer from brain injuries and stroke, and develop motor, sensory, and cognitive problems as a result of neuronal loss in the brain. Unfortunately, the damaged brain has a limited ability to enact repair and current modes of treatment are not sufficient to offset the damage. An extensive list of growth factors, neurotrophic factors, cytokines, and drugs has been explored as potential therapies. However, only a limited number of them may actually have the potential to effectively offset the brain injury or stroke-related problems. One of the treatments considered for future brain repair is bone morphogenetic protein 7 (BMP7), a factor currently used in patients to treat non-neurological diseases. The clinical application of BMP7 is based on its neuroprotective role in stroke animal models. This paper reviews the current approaches considered for brain repair and discusses the novel convergent strategies by which BMP7 potentially can induce neuroregeneration. 相似文献
853.
Dries P.J. Kuijper Bogumiła Jędrzejewska Bogdan Brzeziecki Marcin Churski Włodzimierz Jędrzejewski Henryk Żybura 《植被学杂志》2010,21(6):1082-1098
Question: What are the main driving factors in 70 years of natural dynamics in tree recruitment in the Bia?owie?a National Park? Location: Bia?owie?a National Park, Poland, is one of the least disturbed temperate, lowland forest systems in Europe. Methods: We tested whether fluctuations in large herbivore populations, changes in climate and openness of the forest explained compositional dynamics. Tree recruitment (to size class DBH≥5 cm) was measured on permanent transects (in total, 14.9 ha) six times between 1936‐2002. These data were related to existing data on ungulate density, climatic parameters and estimates of forest openness collected during the same period. Results: Total recruitment of all tree species combined was negatively correlated with total ungulate density and red deer density. The variation in response between species was related to the preferences of herbivores; the more preferred forage species (especially Carpinus betulus) were positively and the less preferred species negatively related to herbivore density. Total tree recruitment rates were not related to climatic parameters and openness of the forest. Only Alnus glutinosa recruitment was significantly related to climatic parameters, and Ulmus glabra related to forest openness, but there were no predictable patterns in recruitment among species in relation to these factors. Conclusion: The present study indicated that changes in large herbivore density have played an important role in driving patterns in tree recruitment and species composition during the last 70 years in Bia?owie?a National Park. In contrast to other studies, increasing herbivore numbers were associated with higher recruitment of preferred and browsing‐tolerant species. Periodical crashes in ungulate numbers, whether human‐induced or caused by natural factors, may offer windows of opportunity for regeneration of a range of tree species and facilitate more diverse and dynamic forest development. 相似文献
854.
Bogdan Suchacz Marek Wesolowski 《Journal of trace elements in medicine and biology》2013,27(2):168-170
The purpose of this study was to investigate the content of trace elements in relation to the composition of domestic herbal mixtures. Cluster analysis, principal components analysis, and self-organizing maps were applied to identify existing relationships. The concentrations of Ni, Pb, Cd, Cr, Cu, Fe, Mn, Zn in 81 samples of herbal mixtures were determined with application of FAAS. The study showed that the levels of trace elements in some herbal mixtures of the same composition were comparable. The projection of herbal samples onto topological maps of adjustable sizes allowed recognition of the identical herbal preparations characterized by dissimilar levels of trace elements. The elements which played the most important role in recognition of the herbal samples were Mn, Ni, Zn and partly Cu, Fe and Cd. 相似文献
855.
Mateusz Baca Danijela Popović Anna Lemanik Sandra Bañuls-Cardona Nicholas J. Conard Gloria Cuenca-Bescós Emmanuel Desclaux Helen Fewlass Jesus T. Garcia Tereza Hadravova Gerald Heckel Ivan Horáček Monika Vlasta Knul Loïc Lebreton Juan Manuel López-García Elisa Luzi Zoran Marković Jadranka Mauch Lenardić Xabier Murelaga Pierre Noiret Alexandru Petculescu Vasil Popov Sara E. Rhodes Bogdan Ridush Aurélien Royer John R. Stewart Joanna Stojak Sahra Talamo Xuejing Wang Jan M. Wójcik Adam Nadachowski 《Journal of Biogeography》2023,50(1):183-196
856.
In the paper we consider the existence of calcium travelling waves for systems with fast buffers. We prove the convergence
of the travelling waves to an asymptotic limit as the kinetic coefficients characterizing the interaction between calcium
and buffers tend to infinity. To be more precise, we prove the convergence of the speeds as well as the calcium component
concentration profile to the profile of the travelling wave of the reduced equation. Additionally, we take into account the
effect of coupling between the mechanical and chemical processes and show the existence as well the monotonicity of the profiles
of concentrations. This property guarantees their positivity. 相似文献
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860.
Anne E. Thessen Paul Bogdan David J. Patterson Theresa M. Casey Csar Hinojo-Hinojo Orlando de Lange Melissa A. Haendel 《PLoS biology》2021,19(3)
Decades of reductionist approaches in biology have achieved spectacular progress, but the proliferation of subdisciplines, each with its own technical and social practices regarding data, impedes the growth of the multidisciplinary and interdisciplinary approaches now needed to address pressing societal challenges. Data integration is key to a reintegrated biology able to address global issues such as climate change, biodiversity loss, and sustainable ecosystem management. We identify major challenges to data integration and present a vision for a “Data as a Service”-oriented architecture to promote reuse of data for discovery. The proposed architecture includes standards development, new tools and services, and strategies for career-development and sustainability.Data integration is key to the reintegration of biology and the pursuit of global issues such as climate change, biodiversity loss, and sustainable ecosystem management. This Essay defines the primary challenges in data integration and presents a vision for a "Data as a Service" (DaaS) oriented architecture that enables frictionless data reuse, hypothesis testing, and discovery. 相似文献