Wavelet Transform and Image Processing

This paper presents systematically a method for image compression/decompression viawavelet transform.It consists of filter,quantization and Huffman coding etc..Different methodshave been compared.Finally,some suggestions for further studies are proposed.In fact,the paper isa summary of our recent research.     

Prox1 function controls progenitor cell proliferation and horizontal cell genesis in the mammalian retina

Retinal progenitor cells regulate their proliferation during development so that the correct number of each cell type is made at the appropriate time. We found that the homeodomain protein Prox1 regulates the exit of progenitor cells from the cell cycle in the embryonic mouse retina. Cells lacking Prox1 are less likely to stop dividing, and ectopic expression of Prox1 forces progenitor cells to exit the cell cycle. During retinogenesis, Prox1 can be detected in differentiating horizontal, bipolar and AII amacrine cells. Horizontal cells are absent in retinae of Prox1-/- mice and misexpression of Prox1 in postnatal progenitor cells promotes horizontal-cell formation. Thus, Prox1 activity is both necessary and sufficient for progenitor-cell proliferation and cell-fate determination in the vertebrate retina.     

Unprecedented Arctic ozone loss in 2011

Chemical ozone destruction occurs over both polar regions in local winter-spring. In the Antarctic, essentially complete removal of lower-stratospheric ozone currently results in an ozone hole every year, whereas in the Arctic, ozone loss is highly variable and has until now been much more limited. Here we demonstrate that chemical ozone destruction over the Arctic in early 2011 was--for the first time in the observational record--comparable to that in the Antarctic ozone hole. Unusually long-lasting cold conditions in the Arctic lower stratosphere led to persistent enhancement in ozone-destroying forms of chlorine and to unprecedented ozone loss, which exceeded 80 per cent over 18-20 kilometres altitude. Our results show that Arctic ozone holes are possible even with temperatures much milder than those in the Antarctic. We cannot at present predict when such severe Arctic ozone depletion may be matched or exceeded.     

Fast Implementation of Iterative Reconstruction with Exact Ray-Driven Projector on GPUs

Iterative methods are popular choices in image reconstruction fields due to their capability of recovering object information from incomplete acquisition data.However,the computation process involves frequent uses of forward and backward projections that are computationally expensive.Past research has proved that a forward projector that can produce high quality images is crucial to achieve a good convergence rate.In this paper a high performance iterative reconstruction framework is introduced,where two mo...     

Netrins and netrin receptorsRID="†"ID="†" Review

The formation of precise connections between neurons and their targets during development is dependent on extracellular guidance cues that allow growing axons to navigate to their targets. One family of such guidance molecules. conserved across all species examined, is that of the netrin/UNC-6 proteins. Netrins act to both attract and repel the growing axons of a broad range of neuronal cell types during development and are also involved in controling neuronal cell migration. These actions are mediated by specific receptor complexes containing either the colorectal cancer (DCC) or neogenin protein, in the case of the attractive receptor, or UNC-5-related proteins, in the case of the repellent receptor. Recent work has identified a key role for intracellular cyclic nucleotide levels in regulating the nature of the response of the growing axon to netrins as either attractive or repulsive. Netrin-DCC signaling has also been shown to regulate cell death in epithelial cells in vitro, raising the interesting possibility that netrins may also regulate cell death in the developing nervous system.