Nitrogen is the most abundant gas in our atmosphere and is luckily quite inert. It generally just sits there doing nothing while the more chemically relevant gasses like oxygen and carbon dioxide interact with our bodies. Almost all plants, however, require some nitrate (NO3–) in order to grow. There is a natural cycle of nitrogen where animals who die release the nitrogen from what they’ve eaten back into the soil and also an atmospheric cycle where occurrences like lightening can convert nitrogen in the atmosphere into nitrogen dioxide (NO2) which is then dissolved by the rain and ends up in the soil as a nitrate. These natural methods can sometimes be too slow for industrialised agriculture and so ammonia (NH3) can be added which is changed into nitrates by bacteria in the soil.
One of the more abstract aspects of global warming, from my perspective, is the tangible short term results. It is predicted that an increase in the sea’s surface temperature will result in an increase of tropical cyclone intensities. The sea is the primary of source of energy which feeds the storm and the oceans where cyclones are known to develop (North Pacific and North Atlantic) have increased by half a degree over the last 50 years. Predictions of increased destruction stray wildly and many previous studies have left out key sections on the increased size of cyclones with increased temperature. Another fault is that previously gathered data doesn’t always record storm sizes resulting in studies based on the assumption of a maximum possible storm size. If the increase of sea’s temperature does increase the size of storms as is firmly believed, these past predictions require updating.
In classical physics it is a simple fact that if you knew enough information nothing could be beyond prediction. If quantum physics was to be ignored someone could have calculated the entire universe provided they knew every detail of the big bang. When companies make predictions they are not of this kind. You will probably heard the practically vapid phrase that “correlation does not equal causation” but the simple fact is that correlation is the only thing required. If 90% of people who buy pens online also buy paper later, who cares if its causation. Advertisements will appear for various notepads because it is statically likely the pen buyer will soon be looking for one. In a similar way it is estimated that some life insurance companies have so much information that they can predict the date of someone’s death (based on neighbourhood, average income, previous family medical records, ect) to within a year.
As is mentioned quite concisely in this page on waves, waves that meet each other undergo superposition and either constructive or destructive interference. This can be seen straight from Maxwell’s equations and so for a long time this was not questioned. It was eventually discovered that it is actually possible for photons to collide with each other in an effect called light by light scattering. According to particle physics such an interaction where two photons end up bouncing off each other is controlled by the W± bosons. Despite considerable effort being exerted from some very powerful lasers there has still not been direct observational evidence of elastic light by light scattering. Most of the information for its existence has come from parallel observations involving the anomalous values of the magnetic moment in electrons and muons.
I was considering writing this weekly roundup on the importance of peer reviewed publication. I could have written many paragraphs on the essential nature of experts evaluating papers, but luckily I don’t have to. A man named Peter Hadfield who owns the youtube channel potholer54, has recently published this video (slightly inappropriate for children) which I was lucky enough to find. In it, he articulates in a much more proficient way than I could the difference of quality between scientific journals and the importance of reputation in the review process. All I really need to add is my own little analogy. In a game of sudoku there may come a time when you realise that you have somehow managed to place two 9s in the same row. The problem is not just as simple as erasing both numbers and rederiving your logic as it is impossible to know how many other numbers in many other places were put there based on a faulty 9. If one ridiculous paper manages to sneak into a respected journal then it will be trusted by the nature of it just being there and once its been used as a supporting citation in another set of papers the problem is already out of control.
Hopefully the importance of scientific purity is now quite a bit clearer. Until tomorrow, goodnight.
When a system’s particles interact under a repulsive inverse power law, it means that particles will repel each other and the force with which one particle experiences from another can be stated generally as:
F = k / rn
where F is the force exerted on the particle, k is a constant, r is the distance between the two two particles and n is the order of the interaction.
It is a well known fact that the human heart uses electrical currents in order to keep the cardiac muscles pumping in time. The current it taken to the muscle cells by conducting cells which pass the current through the heart to the correct places. The sinoatrial node is the originator of the signal which then moves to activate the atria and then the ventricles.
Now I actually have been diagnosed with having first degree heart block, which is so minor it doesn’t even cause noticeable bradycardia (slowing of heart beat). This means that the due to a lack of conductivity in my heart there is a slight delay between the contraction of the atria and the ventricles although not enough to have any noticeable adverse effects. For others though, it can be a lot more serious. Cardiovascular diseased cause the highest number of deaths in the world according to the World Health Organisation (WHO?), with many of these being caused by arrhythmias.