The Cowan-Reines Neutrino Experiment

The Cowan-Reines Neutrino Experiment was the first experiment to prove the existence of a particle known as a neutrino (the experiment actually proved the existence of its antimatter counterpart, the anti-neutrino). 

This particle was first proposed by Wolfgang Pauli. Investigations into the Beta decay after the discovery of radioactivity revealed that the electron emitted during Beta decay possessed a wide range of energy (a continuous energy spectra). Certainly when the energy of the electron is below the maximum, due to the laws of energy conservation, the remaining energy must be transferred somewhere else rather than disappear. Thus the neutrino is proposed as an additional particle released in Beta decay which possesses a certain amount of energy as well. This would be the source of the remaining energy released in the Beta decay when the electron's energy is not at the maximum. 

The set up of the experiment was simple. Two tanks of water was set up with 40 kilograms of Cadmium Chloride dissolved into the water. The entire set up was then placed in close proximity to a nuclear reactor, where the most reliable large source of neutrino flux could be found. 

Should the experiment react in accordance to their prediction of the neutrino, in accordance to the predicted expectation of inverse Beta decay (obviously obtained by the knowledge of Beta decay), the anti-neutrino produced from the nuclear reactor should interact with a proton to create a neutron and a position. The position would quickly annihilate with an electron to create a burst of Gamma radiation, which serves as an indicator that the reactions of the experiment had worked in accordance to their expectations. As an added precaution, Cadmium Chloride was added into the tank as a neutron absorber to absorb the neutron produced as part of the reaction. This absorption by the Cadmium (108) atom would create another isotope of Cadmium, Cadmium (109) with a release of Gamma radiation as well. It was mathematically calculated that the positron-electron annihilation would occur approximate 5 microseconds before the absorption of the neutron as it takes more time for the neutron to encounter a Cadmium atom. Hence if the experiment produces two Gamma ray bursts spaced 5 microseconds apart, it would be the unique signature that reaction occurred in accordance to the theories and thus the theories are correct. 

SUMMARY

Via the inverse beta decay, the predicted anti-neutrino should interact with a proton to produce a neutron and positron. The position annihilates with an electron to create an initial burst of γ radiation. Cadmium Chloride is added into the tank as a neutron absorber. Mathematical calculations implied that it would take approximately 5 microseconds for the product neutron to encounter and react with the Cadmium (108) to produce Cd (109) isotope and γ rays. The two bursts of γ radiation is a conclusive signature for the presence of neutrinos.

Sources: 

1. Cowan-Reines Neutrino Experiment: https://en.wikipedia.org/wiki/Cowan%E2%80%93Reines_neutrino_experiment

2. ''Neutrino'' by Frank Close

3. Beta decay: https://en.wikipedia.org/wiki/Beta_decay

Antibiotics Resistance: What A Layman Should Know

On the 21st of May the BBC posted an article titled ''Global antibiotics 'revolution' needed'' to address the need for a drastic improvement in our habits for antibiotics use. The 21st of May issue of the Economist featured an article that concerns the rise of the antibiotics resistance.

These articles are an excellent reminder to all of us of the lurking problem of antibiotics resistance, a problem with potentially catastrophic results. Antibiotic resistance is an ever-existing problem that researchers have been fighting from the very first use of antibiotics.

The reason for the problem is simple: Bacteria constantly evolves.

Antibiotics acts as a selection pressure to the bacteria, as a result, wipes out bacteria with insufficient resistance to the antibiotics while bacteria with sufficient resistance to the antibiotics continue to thrive, replace the population and create a new population with resistance to antibiotics. A detailed explanation of the mechanism can be easily found online for example on wikipedia, or within the economist article as mentioned above. A example of the problem of antibiotics resistance is with the case of a difficult-to-treat strain of ''super-gonorrhea''.  

Research is constantly conducted to address the issue of antibiotic resistance with the creation of new antibiotics or alternative measures. However, on our side (as a normal citizen), we can help combat the problem of antibiotic resistance by using antibiotics appropriately. Poor usage of antibiotics will work in favour of bacteria as it acts as a catalyse for antibiotics resistance. The BBC reports that in the ''Review on Antimicrobial Resistance'', by 2050, 10 million people could die each year as a result of antibiotics resistance.

Therefore, proper use has the potential to save millions of lives.  

1. One must understand that antibiotics have no use on virus infections.

When one falls sick, make an effort to understand the nature of the ailment. A infection in the respiratory tract or the intestine that causes diarrhoea? That could possibly be an influenza virus infection in which antibiotics does not have an effect on. While most of the time our doctors are able to diagnose and prescribe for our ailments accurately, if one were to purchase medication over the counter, be sure as to buy antibiotics only when it is applicable and required.

2. One must finish the entire course of antibiotics medication. Unless otherwise stated by a medical practitioner.

Often times our doctors will instruct us to finish our entire course of antibiotics medication even if we appear to have recovered from our illnesses. The reason for this is that our apparent ''recovery'' from the illness may not be entirely complete, while what we observe is instead the recovery from the obvious symptoms of the illness. Traces of the bacteria may still survive within your body which may develop a resistance to the antibiotics if effort is not taken to completely flush out the bacteria within your body.

Sources

1. BBC Article, ''Global antibiotics 'revolution' needed'': http://www.bbc.com/news/health-36321394
2. Super-Gonorrhea: http://www.telegraph.co.uk/news/2016/04/17/
3. More About Antimicrobial Resistance: https://en.wikipedia.org/wiki/Antimicrobial_resistance

Euler's Identity- Algebraic Proof

                                             e^iπ + 1 = 0

Euler's Identity as seen above is often described as the most beautiful equation in the world, where the most fundamental constants of mathematics come together to produce a simple equation.

The term e refers to the base of the natural logarithm, ln, of value 2.71828....
π, 3.14159… is the ratio of the circumference of the circle to its diameter.
The term i refers to the imaginary number of the square root of -1.

The proof for the equation is easily presented through the use of an argand diagram http://en.wikipedia.org/wiki/Complex_plane

The algebraic proof of the equation can also be achieved fairly easily with some prior knowledge on complex numbers, differentiation, Maclaurin's series and a little bit of algebraic manipulation.

Firstly, obtain the Maclaurin's series for e^x. A Maclaurin's series is an expression of a function as a power series. It can be obtained by substituting the variable 'x' of each term of the function with 0, with the first term of the function as the function itself, and each subsequent term as a differentiated form of the previous term.
The Maclaurin's series for sinx and cosx should then be obtained. (Obtaining the first few terms for each series should suffice.)

List of several Maclaurin's expansion for various common functions.

Next, replace the 'x' term of the e^x series with 'ix' and we will soon realise that the real part of the solution corresponds to the Maclaurin's series for cosx while the imaginary part of the solution corresponds to that of sinx. Thus, replace the series for the real and imaginary parts with cosx and sinx respectively.

Thereafter, we would obtain the equation e^ix = cosx + isinx
                                                              e^ix = cosx + isinx

By replacing x with π, we will obtain e^iπ = -1. Hence e^iπ+1=0

Sources:
Proof: The pleasures of Pi,e and other interesting numbers (By Yeo Adrian)
Photos are obtained from:
1. http://en.wikipedia.org/wiki/Euler's_identity (Equations)
2. http://www.seab.gov.sg/aLevel/2014Syllabus/ListMF15.pdf (Standard series)

Extrasolar planets

Extrasolar planets are planets not found from our solar system in other words outside of our solar system. Recently astronomers have been finding more and more extrasolar planets and news of these planets appear once in a while. 


To introduce about extrasolar planets one important word we must know is eclipses. A common misunderstanding is that eclipses are only solar or luna eclipse. However, many phenomena are classified as eclipses rather than just the aforementioned occurrences. The proper definition of eclipse is  'The passage of one celestial body in front of another, cutting off the light from the second body'.

Extrasolar planets are difficult to find due to their distance, and the fact that the star they orbit tend to conceal the planets due to their sheer brightness and size relative to the planet. Quoted from a documentary 'The universe' in (discover channel or was it history channel) its like finding a flee in front of a headlight. However, it is possible to find it when an eclipse occurs. When a planet's orbit is positioned exactly at the astronomer's vantage point, a slight drop in the brightness of the sun at a specific point can be detected which suggests that a crossing planet is blocking out part of the sun where it is currently at as it travels. Of course there are many false alarms, but this method can enable astronomers to determine the size of the planets. Sadly most of the planets that are detected are huge gas planets which are big enough to cause a drop in brightness of us to detect.

Definition of eclipse: http://space.about.com/od/glossaries/g/eclipse.htm

Confusing world of Anthropology

I've always had a keen interest in Anthropology. 
http://www.youtube.com/watch?v=crwPkPWcqBY
I was compelled to share this link after watching the video of an old BBC documentary ''walking with beasts''. This episode, talks about the Australopithecus as our ancestor around 3.5 million years ago. This video is pretty old.
Anyway,it is believed that Australopithecus is the species that led to the evolution of the 'homo' genus, that they gave rise to modern humans(homo sapiens sapiens) and our closely related species such as Neanderthals(homo sapiens neanderthal). I would not touch on this topic as of now, but I will leave some interesting facts behind. Ps: Its not really related to the show.
1: A famous fossil specimen nick named 'Lucy' belongs to this specie.
2: The last Human-Chimpanzee ancestor is predicted to have lived 5-6.3 million years ago.
3: Modern humans inter-bred with at least Denisovans and Neanderthals.
4: Yet a newly discovered  hominid specie the Sahelanthropus tchadensis is 7 million years old. Anthropologists are deciding if it is a common ancestor of humans and chimps. If it is not, things would get alot more complicated.
More on Australopithecus: http://humanorigins.si.edu/evidence/human-fossils/species/australopithecus-afarensis

Longshore drifts and longshore currents

After today, I will start posting on a weekly basis every Saturday. I will also include urls of the websites which I get my information from. I've been a little lazy recently, so this post would be on something I've learned in secondary school, hope it would be useful.


Waves and currents causes transportation of sediments in the coastline (the place where the land and sea meets and interacts) Longshore currents and longshore drifts are terms we need to know regarding this topic. They can be a little confusing.

Longshore currents are flows of water that move parallel to the coast. It is generated by winds, tides and waves that approaches the coast at an angle driving the flow of water along the length of the coastline. Very specifically, it is defined as such... ''the longshore current is the dominating current in the nearshore zone. It is running parallel to the shore. The longshore current is generated by the shore-parallel component of the stresses associated with the breaking process of obliquely incoming waves, the so-called radiation stresses, and by the surplus water which is carried across the breaker zone across the coastline.''


Longshore drift on the other hand refers to the movement of sediments along the coastline. How it occurs is simple. When waves approach the coast at an angle due to wind direction, it carries sediments to the coast at an angle. However gravity only causes the sediments to move downwards perpendicularly to the coastline thus the sediments would travel along the coastline in a zig-zag motion when it is repeatedly carried at an angle and returned vertically downwards. Note: Sediments are carried to the coast when a wave crashes onto the coast, know as a swash. The motion where the seawater retreats back into the sea is known as a backwash. The backwards motion that pulls the sediments back. Longshore currents may result in longshore drift. This is illustrated below: (due to the fact that my 2 mega pixel camera was horrible at taking good photographs and that I could not operate my new scanner I could not draw out the diagrams for use)  

I do not own this photograph check links below credits go to the website

The world's longest naturally occurring spit, the 'Dungeness Spit' is found in America. Spits are one type of coastal landform that we see, along with cliffs, beaches, bays just to name a few. It is a result when longshore currents that transport sediments in the sea encounters a place of shallow sheltered water, enabling the sediments to be deposited in those regions. The accumulation of these sediments along the direction of the long shore current creates a narrow ridge of sand we identify as a spit. 

I do not own this as well. Check links below credits go to the website

Stuff about longshore drift: From my textbook
Photo of spit: http://tidelineconsultingllc.com/
Longshore current definition: http://www.coastalwiki.org/coastalwiki/Longshore_current
More about longshore current: http://www.usoceansafety.com/safety/popup/lscurrent.asp
Photo on longshore drift:   http://cgz.e2bn.net/e2bn/leas/c99/schools/cgz/accounts/staff/rchambers/GeoBytes/GCSE%20Revision/Glossaries/Glossaries/Glossary%20Extra%20Page%20Links/LongshoreDrift1.gif

Ocean conveyor belt: Thermohaline circulation

I only know this much about the Thermohaline circulation. Its information would be useful to readers but there are two things I would like to discuss about at the end of my article. 
The Ocean conveyor belt or more accurately, the thermohaline circulation refers to the continuous cycle of water in the ocean due to its temperature and salinity. The working principle behind it is that water from different parts of the ocean has differing densities, whereby colder saltier water is denser than warmer less salty sea water. (expansion of liquids) Water which is less dense tends to float while denser water tends to sink, resulting in the movement of water in the oceans to achieve this balance.
How did this different density occur in the first place?
In the North Atlantic, winds blowing over the ocean remove latent heat of vapourisation as the water evaporates, becoming cooler. Less water in the ocean coupled with the same amount of salt causes the water to become denser. In addition, when ice is formed on the ocean in those regions, pure water tends to freeze rather than salt water. Again, less water in the ocean to dissolve the salt would cause the concentration to increase even further. This denser ocean water forms the North Atlantic Deep water (NADW) which flows southwards through deep abyssal plains found along the Atlantic.    
Down to the Antarctic this denser ocean water then flows along the Antarctic continent mixing with the Antarctic bottom water to give 'common water' where it splits up to the Indian Ocean and Pacific Ocean. Following this route.

The Pacific Ocean having a slightly higher water level than the Atlantic Ocean would flow its upper most water through Indonesia to replace the water from the Atlantic that had travelled along Antarctica. Thereafter it travels North back to Greenland where it all began, starting the cycle all over again. 

Ps: Any readers please enlighten me on the terms 'over turning' and 'Haline forcing' I did not use it in my text in fear of being inaccurate! Picture from politicalclimatewordpress.com

Permian mass extinction in a nutshell

Based on the knowledge acquired from discovery channel, do enlighten me if you happen to know some specific details which I left out. 


Trigger: Volcanic eruptions(Siberian Traps) lasting for up to a million years causing large amounts of sulfur dioxide and carbon dioxide to be released.
Direct consequence: Sulfur dioxide would have caused acid rain that damages the eco system, but the damage would not have been so extensive.
The carbon dioxide released in such enormous quantities would cause severe global warming that kills off 1/3 of land dwellers at that time.
Indirect consequence:The heated planet with its warmer oceans would devastate the 'conveyor belt' preventing proper circulation of oxygen in the ocean. With the absence of oxygen in the ocean marine aerobic life would die out. It also causes purple sulfur bacteria to thrive. Which is, bacteria that survives without oxygen. In addition, these bacteria produces highly toxic hydrogen sulfide which adds on to the devastation done on the marine life of the Permian period.  
The heated ocean would also cause highly temperature sensitive methane hydrate, combination of methane and water in its solid form frozen at the bottom of the ocean, to melt releasing methane which is a very potent green house gas. It further aggravates the problem of global warming increasing Earth's temperature even further and wiping out even more life on Earth in the Permian period.
Ps: I will be writing a few posts about the conveyor belt and methane hydrate really soon to further explain how it plays a role in the Permian mass extinction!      

Criteria to be classified as a planet

Why did Pluto lose its status as a planet in 2006? Its old news, but I hope it helps!
There are 3 criteria that determines a planet.
1: The object must have sufficient mass for its self-gravity to overcome its 'rigid body forces' and assume a hydrostatic equilibrium shape. Hence becoming round.
2: It must orbit around a star, hence our moon cannot be considered as one.
3: It must have 'cleared its neighbourhood around its orbit' of everything except much smaller objects. This rules out Pluto as a planet as its orbit which has Neptune, which is much larger, being in close proximity due to their unique orbits that seem to overlap each other on a 2 dimensional plane.
Source: David A Rothery

Solidification of eggs

We all know that when eggs are cooked over a long period of time it becomes hard boiled. Why is it so when liquid water boils and solid ice melts but liquid eggs turn solid?
Actually in eggs, it contains proteins such as Ovalbumin. In proteins, the basic unit of amino acid forms a chain of polypeptide which then coils to form a 3 dimensional shaped protein. Its shape is held in place by weak hydrogen bonds that can break under heat. When we cook, the hydrogen bonds that keep the protein in its 3 dimensional shape breaks causing the protein to lose its original shape and become denatured. The denatured protein in the eggs would then be long coils of polypeptide that ends up forming an interconnected mass with each other becoming a solid. A hard boiled egg is then formed.

Great oxygenation event

Disclaimer: The stuff I share is from what I've read and learned. It may be extremely vague. I only hope to present the things I learned in a more simple manner for understanding.(if it even helps) and maybe to discuss. 


The great oxygenation event is the point where oxygen became a permanent part of our atmosphere that happened about 2.4billion years ago. Before that, oxygen is produced by photosynthesis, but quickly combines with elements (such as iron), and organic matter and does not stay in the atmosphere. The great oxygenation event happened when there are not enough of those reactants on the surface to react with the oxygen since they were already reacted to form compounds. This cause oxygen to remain in the atmosphere and accumulate over time.
Oxygen is produced by cyanobacteria which can carry out photosynthesis. The word 'cyano' refers to the colour of the bacteria, which is actually blue-green algae.
Note: Another reason for the fact that oxygen did not immediately accumulate in the atmosphere is that it reacted with methane first, which was present due to other bacteria at that time, to give carbon dioxide.