In mathematics there are many problems that seem almost ridiculously pointless and it makes you wonder why such things are of any interest at all. An example would be the concept of vertex colouring of graphs. This is simply taking a graph and “colouring” each node so that no two nodes of the same colour have an arc connecting them. Generally the aim is to minimise the number of colours required by reusing colours whenever possible. Of course this exercise has applications for computer programming and scheduling algorithms and so, as always, even the most useless looking maths comes to a purpose somewhere.
Nonvolatile memory is the memory normally used as the backup on a computer. Most people will have heard of random access memory (RAM) which is considered volatile because if the computer is shut down all the tiny capacitors (as this is what the memory chip is made from) discharge and so the information stored as RAM is lost. Nonvolatile memory persists even after the computer has been switched off and on again and in its most basic form is literally printing out the information in a format that can be easily reinserted. Magnetic tape is probably the most famous of this type of memory.
Computers are ultimately not very intelligent things. They can only really do what they are told to do and this also means they see what they get told to see. This is why there is always the danger of someone simply setting up their laptop on a public network, that doesn’t have proper security, and having their laptop announce “I am a router.” Computers will simply believe this statement and so will start sending information to this laptop which can copy any data before sending it on its way. This is why entity identification is such an important part of cryptography, making sure it is certainly the individual you think it is.
Today’s news leads on very well from yesterday’s as it is likewise looking at the physics of secondary low energy electrons, very specifically the effect of these electrons on water, the main components of most cells. Despite the electrons being relatively low energy, with most not surpassing about 10 eV, some acute damage can still be done and it was found about a decade ago that the damage DNA receives does not necessarily scale with energy of the damaging electrons. In order to understand the exact interaction of electrons with the water in cells many experiments have been carried out to attempt to understand the process of the electrons transferring energy. This study aims to improve on this kind of work by offering a more advanced and specialised model for the water that makes it act in a much more similar way the liquid found in cells. Details about the electron configuration along with bonding and antibonding electrons were imputed. The phonons within the water were only given one standing wave state which represents the limited environments the water would be in within a cell.
When vertebrates run their running style is defined as a dynamic gait with minimal contact with the ground. When petrified footprints are found it is possible to work out how fast the animal was moving when it made them based on how deep the foot sank into what would have been mud or sand. As humans transition into a run they begin to leave the ground entirely for part of the running cycle. All insects have six legs they use something called a tripod gait, shown below, where there are always three legs constantly on the ground (except for some rare examples):
I am lucky enough to have a mathematician as a friend who specialises in modelling and subsequent prediction of disease spread. The study of the spread of diseases was actually started by William Hamer in 1928 with his published test Epidemiology Old and New. The basic idea that he realised is that when dealing with something as wide spread as a plague the action of any one individual is irrelevant. Only the actions done in mass by significant number of the population need to be considered and the results will still be applicable. To simplify further each individual in the population was put in one of three groups: susceptible, infected and removed (not necessarily dead as immune individuals are in this category). A series of differential equations can then be constructed representing the rate at which people change between these categories with the size of infected increasing the rate of infection for example.
When pictured in the mind Native Americans are seen sitting with a massive feathered headgown and painted skin on the back of a horse. Of course this is a very post Columbus view as horses (and almost all other farmyard creatures) are not native to the Americas and were brought over by Europeans. Although in a way horses do come from the American continent as about ten thousand years ago (double the time humans have been around) the only horse population in the world was in North America but then migrated leaving no left by the time humans turned up. Of course the migration history of horses is quite interesting but even more so is the migration pattern of human over the millennia.