Spatial-temporal actin dynamics during synaptic plasticity of single dendritic spine investigated by two- photon fluorescence correlation spectroscopy

In the content of my thesis, the construction and calibration of a setup that combined conventional wide field fluorescence microscopy (FM) and two-photon fluorescence correlation spectroscopy (2P-FCS) was first described. The combination of FM and 2P-FCS allowed the investigation of the actin dynamic changes at higher temporal resolution and to gain better insights into the dynamic behavior of the different forms of actin filamentous structures. Samples investigated in the course of this study were living neuronal cells (CA3) that had been transfected with eGFP-actin and fCherry to simultaneously monitor changes in actin dynamics and morphology with the function of Tetraethylammonium (TEA) induced LTP. The actin dynamics before and after TEA stimulation was scrutinized to correlate with the morphological plasticity after long-term potentiation (LTP).  Using FCS measurement, we can distinguish two groups of actin filaments within living cell by two-component fitting models. Further, the absolute particle number and brightness can be compared before and after TEA stimulation. We conclude that dendritic spines underwent morphological enlargement with the function of TEA stimulation are correlated to dynamic changes of actin filaments. These more dynamic actin filaments serve as an important role to drive morphological enlargement after LTP

The consistency of estimator under fixed design regression model with NQD errors

In this article, basing on NQD samples, we investigate the fixed design nonparametric regression model, where the errors are pairwise NQD random errors, with fixed design points, and an unknown function. Nonparametric weighted estimator will be introduced and its consistency is studied. As special case, the consistency result for weighted kernel estimators of the model is obtained. This extends the earlier work on independent random and dependent random errors to NQD case

Plant invasions in China : an emerging hot topic in invasion science

China has shown a rapid economic development in recent decades, and several drivers of this change are known to enhance biological invasions, a major cause of biodiversity loss. Here we review the current state of research on plant invasions in China by analyzing papers referenced in the ISI Web of Knowledge. Since 2001, the number of papers has increased exponentially, indicating that plant invasions in China are an emerging hot topic in invasion science. The analyzed papers cover a broad range of methodological approaches and research topics. While more that 250 invasive plant species with negative impacts have been reported from China, only a few species have been considered in more than a handful of papers (in order of decreasing number of references: Spartina alterniflora, Ageratina adenophora, Mikania micrantha, Alternanthera philoxeroides, Solidago canadensis, Eichhornia crassipes). Yet this selection might rather reflect the location of research teams than the most invasive plant species in China. Considering the previous achievements in China found in our analysis research in plant invasions could be expanded by (1) compiling comprehensive lists of non-native plant species at the provincial and national scales and to include species that are native to one part of China but non-native to others in these lists; (2) strengthening pathways studies (primary introduction to the country, secondary releases within the country) to enhance prevention and management; and (3) assessing impacts of invasive species at different spatial scales (habitats, regions) and in relation to conservation resources