Interesting articles about science and technology

These are some articles about cancer research and protein sequencing.

Also - here is some useful background information from Wikipedia: gene expression and cellular differentiation.

In a DNA sequence, very few of the nucleotides are expressed at a time (used in protein generation). The study of what influences which genes get expressed seems very interesting. Also interesting is the drastic effect that small changes (a single skipped nucleotide, a slight reordering of segment of nucleotides) can have. And the cell's mechanisms to detect and correct errors.

Interaction between virus and bacteria are also very interesting. A virus has genes, but no mechanism to express and replicate them. To do this, they need a host (like bacteria, plants, and animals). The virus breaks down the cellular membrane or wall and injects its DNA into the cell. Then the RNA and other cellular structures reproduce the virus' DNA and express the genes to form new virus-llama-beings. The amazing part is that the virus is somehow 'intelligent' enough to toggle how virulent it is. If it infects and kills too many hosts, it won't be able to optimally reproduce. So, it can somehow cause bacteria to incorporate the virus gene sequence into the bacteria gene sequence. And this can be very beneficial to the bacteria, because it introduces genetic diversity into the bacteria, and sometimes causes favorable mutations. This is maybe how new species of bacteria are formed. ANother way new species of bacteria arise are when two different species swap fragments of their gene sequences, and create two new sequences.

My husband's dad was explaining his work on atmospheric spectroscopy, and I think you may find it very interesting. To measure the composition of molecules int he atmosphere, they get air samples. Then they break apart the molecules, either by applying lots of energy, or by ionizing them - the excess electrons allow all the elements to have full valence electrons, and give them all negative charge, so that they break apart. Once the molecules are broken up into individual elements or smaller molecules, the process of spectroscopy will separate the types of elements and molecules. The weight of each element or small molecule in the groups can be determined by its posiiton. The atomic weight can then be used to uniquely identify the element or small molecule.

Image compression involves throwing away all redundant information. The higher frequency variations in an image are less recognizable by the human visual system. Sometimes, they are ignored to the extent that adding white noise to an image produces no noticeable effect. Because of this, a very efficient way to compress images is to transform it into a frequency domain (based on pixel intensity vs. spacial coordinates), then throw away or represent with coarser accuracy, the coefficients of the higher frequencies. When the reverse transformation is done during decoding, enough information is there to reconstruct a good-enough quality image. In video compression, the human visual system is not sensitive during significant changes in frames. So, if there is a sudden scene change, the frames directly before and after the change can be represented more coarsely, and can be more compressed.