All posts by megr090

Why You Should Get a Flu Shot This Season

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It is again the season of the influenza virus – from October to February we see influenza outbreaks all over the United States and throughout other parts of the world.  So, most people are faced with the question: should I get the flu shot?

Barring exceptions (allergies to a component of the vaccine, etc.), the answer should be YES!

Reason 1: It prevents you from getting sick.  Contrary to what a lot of people believe, vaccinations work.

Vaccines contain either a killed or weakened form of  a virus or bacteria.  The idea is to inject people with the killed or weakened form of the pathogen to give the immune system the ability to build up an immune response to a specific pathogen without actually infecting the individual and making them sick.  This allows the immune system to respond stronger and faster if the individual actually does contract the pathogen.

When the killed/weakened form of the pathogen enters the body, the immune system identifies an antigen, which is a substance that the body notices is foreign.  Then, the body releases antibodies, proteins that attack the foreign substances in the body.  The body also generates immune response cells, some of which attack infected cells in the body and others help generate more antibodies.  In the case of an immune response to a vaccine, after the body has neutralized the “threat,” which was really never a threat to the individual due to the weakened form of the pathogen, the immune system generates memory cells.  These cells remember the pathogen and, when they interact with the pathogen again, they can then generate the same response faster and stronger (this is known as secondary response).

The flu shot that is commonly given in the United States is either trivalent (protects against three different viruses) or quadrivalent (protects against four different virues), so even if many strains are going around, it still could help.

There’s always a chance that you get the flu shot and you catch a different strain of the flu.  It happens, but getting the flu shot drastically reduces your chances.  And, even if you get the flu, the vaccine will probably make the illness far milder than it would have been otherwise (because your body is already prepared with antibodies).

Reason 2: Herd Immunity.  If you’re not going to get it for yourself, get it for everyone else who interacts with you.

Not everyone can get vaccinated; sometimes vaccinations are only given to children above a certain age, sometimes people are allergic to an ingredient in the vaccination (some people allergic to eggs cannot take certain vaccines because they use the egg protein to suspend the pathogen), and other times the vaccine just didn’t work as effectively as it was supposed to, because nothing is perfect.  For those people, it vastly minimizes the risk that they get the disease if everyone else is vaccinated, because it decreases the spreading.  It is much harder for the pathogen to move from person to person if it keeps getting eradicated in vaccinated individuals.

(On a separate note, there are egg-free vaccines for people who are allergic and nasal spray for people who are scared of needles.)

How many people need to be vaccinated in order for the disease spread to slow?  We can actually calculate that!

First, we have to consider the reproduction number of a disease (R).  R represents the number of people an infected person would get sick.  Because diseases like measles or the flu are really contagious, their R is very high.  We want R < 1, because then the disease spread is slowing down.  So, to find the proportion of the population that we want to vaccinate (let’s call that V), we want (1-V)*R < 1 (because 1-V represents all the unvaccinated people, and we want a disease in that population to not spread).

So, we can solve for V and get that V > 1-(1/R).  So, if we know the R for the flu, we can actually find the number of people in the population we need to vaccinate.  The problem is, if less people than that proportion V choose to get vaccinated, the disease spreads.  So as many people as possible should get the flu shot!  It can’t hurt for more people than V to get the vaccine, but it can hurt if less people do.

Reason 3: If you’ve never gotten the flu shot and never gotten the flu, that’s not a reason to continue not getting the flu shot. It just means you got lucky in the past, but your chances of getting the flu are still higher without the vaccine.  We want herd immunity as well to protect the whole population, so it’s important that everyone get the vaccine.

If you want to learn more about what goes into vaccines, check out this other post:

Getting the flu is not fun.  It causes deaths across the world and, even at best, you’re in bed for days being miserable.  If getting the vaccine reduces the probability of catching the flu, it’s worth it.

Works Cited

El Nino: The Models, the Forecasting, and The Impacts

El Nino has been in the news a lot lately, because most models predict that we’ll have a huge, “El Nino of the Century” this year. Not only is this super cool because it affects a lot of the world, is about climate forecasting, and has made major news, but I have been spending the summer researching the quality of El Nino models.   Therefore, it seemed fitting to write about ENSO, the mathematics behind the forecasts, and the importance of these particular forecasts.

What is ENSO?

ENSO stands for El Nino Southern Oscillation, which refers to a warming or a cooling of sea surface temperatures in the Pacific Ocean. Warmer temperatures cause an El Nino, cooler temperatures cause a La Nina. The exact causes of ENSO are still being researched, although we do know that easterly trade winds weaken, which reduces a current on the coasts of South America, allowing warmer waters to build. These warmer waters are accompanied by a decrease in atmospheric pressure. El Nino events tend to reach their full strength around December.  You can see in this picture where the warmer waters of an El Nino are:


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These do not happen every year. El Nino or La Nina events happen around every three to five years, and strength varies depending on many variables, including changes in sea surface temperatures and pressure.

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In this graph, red indicates El Nino, blue indicates La Nina – this graph shows how often these vents occur and it shows La Nina occasionally following El Nino.

Why is it important?

ENSO influences precipitation across the world, causing increased rainfall in some areas (yes, including California) and drier areas in others (such as Southern Africa and parts of South Asia). It influences monsoons in South Asia and droughts in Australia. Therefore, forecasting ENSO events is incredibly important.  In the following picture, you can see the effects that El Nino has on the world:

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Some basics about the models.

Before we start talking generally – most of this will only be about the section of ENSO forecasting that I am most familiar with.  In my experience, I have used the Nino 3.4 index – this is a way of characterizing El Nino/La Nina events solely by using sea surface temperature. If sea surface temperature increases over a standard threshold of 0.5 degrees Celsius, then it is considered El Nino conditions. Similarly, if sea surface temperature decreases by 0.5 degrees Celsius, then it is considered La Nina conditions. Anything less than a 0.5 degree change in either direction is considered Neutral conditions.

There are two types of models that are most commonly used in ENSO forecasting: dynamical and statistical models. The dynamical models are models that use physics and our understanding of the climate and atmospheric conditions to simulate what’s going to happen. The use of the physics is very precise and we have a pretty good understanding of how our atmosphere works. Statistical models, on the other hand, involve absolutely no prior understanding of how the climate or the oceans work. Instead, they use statistical analyses based solely on past years of data to predict what’s going to happen. Most of the models in ENSO forecasting are dynamical models.

What do the forecasts look like?

The forecasts look like a cube (or, rectangular prism). If you imagine a three dimensional matrix (or block), along the bottom side, we have time (in months, as we get new predictions every month), along the height side we have lead time. Lead time tells us how far in advance we’re making the prediction. On any given month, when a prediction is made, forecasters will predict the sea surface temperature up to a year in advance. So, if they’re making a prediction now, in August 2015, they will make predictions for August, September, October,… all the way up to August 2016. As you can probably gather, the predictions for August and September 2015 are really good, because we have a much clearer understanding of what’s going on. Predictions with a lead time of 12 months (a year in advance) aren’t as good.

Finally, the last dimension of our cube is ensemble members. When a model predicts things, some part of that prediction involves uncertainty. We don’t know exactly how the atmosphere will behave or exactly what the temperature will be like, so to be safe, we run the model a few times and store that information in different members. Thus, we can have an understanding of the variation in this model. Each model has somewhere on the order of ten members.

That is all the data that’s found when the data from a model is compiled. Then, forecasters use that data to come up with a forecast for the next 12 months.  The creation of the models is difficult, but the issuing of the forecast is also complicated because the forecaster has to sort through the cube of data and separate the noise (random or seasonal climate variations) from the signal (temperature fluctuations due to an impending El Nino or La Nina).

How good are these forecasts?

Well, that depends on your definition of “good”. These are all highly tuned models and, for the most part, they do a good job of forecasting an increase in temperature when an increase happens and vice versa. However, keep in mind that for the last few years we have been predicting an El Nino of a certain magnitude when one failed to appear. Now, that doesn’t necessarily mean that will happen this year (especially because the intensity of the El Nino that is being predicted now is much, much higher than in past years), but these models aren’t perfect.

Something to keep in mind while we look at the forecasts for this year: forecasts that occur in the spring and early summer are not as good as forecasts that occur in the rest of the year. This is known as the spring predictability barrier, and its causes are still being debated. Once we get past that time, forecasts get much more accurate.

So, what’s going on with THIS El Nino?

I mentioned earlier that a standard threshold for an event being considered an “El Nino” is a sea surface temperature increase of 0.5 degrees. Here is the forecast for this year:

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As you can see, we’ve gone above and beyond that 0.5 degree threshold – some models are even going above the 3.0 degree mark, which does not happen very often. So, for these models, pretty much all are in agreement that we’re going to have an El Nino. They disagree to an extent about the intensity of this El Nino, but most are predicting one far above the average.

What are the effects if this El Nino really is that big? Yes, probably California gets the rain that it has desperately needed. We can also predict much more rainfall in other parts of the United States as well. However, according to NOAA, these impacts are not guaranteed – there is a higher probability of increased rain, but it’s not a sure thing. Since ENSO is a Pacific phenomenon, it does not affect the United States as much as tropical countries and those in South America and parts of Asia and Australia. However, either way, this year will be fascinating one for weather and ENSO – we will keep an eye out on the forecasts as we get closer to December!

If you’re interested in learning more, NOAA has a pretty cool ENSO blog that has explanations, discussions, and frequent updates about the forecasts:


Works Cited


Fermi Paradox: Where Are the Aliens?


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During a conversation decades ago, a famous physicist named Enrico Fermi wondered…where is the extra-terrestrial life?  While many people consider the idea of aliens as something from science fiction (and so far, it has been), it seems crazy that humans are somehow the only life in a vast, if not infinite, universe.  Thus, we have the Fermi Paradox: by laws of probability, there should be extra terrestrial life (we’ve seen many Earth-like planets that could potentially support life), but so far, we have seen no evidence of them.  Where are they all?

Of course, we have no answer to this paradox, but many potential explanations have been suggested since Fermi posed this question in the 1940s.  Here are a few possible reasons why we haven’t met any of the aliens in our universe:

(1) They just don’t exist – this would imply that Fermi’s assumption that there must be many other civilizations in the world is false.  Maybe we are the first life in the galaxy, maybe the idea of the “Goldilocks Planet” holds (that is, only very few planets have the ability to sustain life because they need very specific conditions of temperature and atmosphere), and on those very few planets, the actual creation of life is very rare and requires even more specific conditions.  Based on assumptions made for many years by scientists, this hypothesis seems more unlikely than others – we have found Earth-like planets already that could sustain life.

(2) They exist, but cannot communicate with us – maybe we’re the only life in the universe to become intelligent.  Maybe, like us, they are still developing their space travel technology and just haven’t gotten to the point where they can reach out to us.  Maybe they are reaching out to us, and we can’t interpret the signals for some reason.  Some scientists have suggested that their physics and mathematics are so different from ours that it’s impossible to communicate with them.  Maybe they don’t want to communicate with us.  And finally, the most concerning, that intelligent civilizations like ours just don’t last that long, due to overpopulation, wars, or other disasters.  Therefore, no civilization has been able to develop to the point of interstellar communication, even though they exist.

(3) They are already here – this one seems to be directly from some science fiction/horror/Twilight Zone stories, but they have been and are being seriously considered.  Maybe the human race came from alien civilizations, and thus we are the extra terrestrials.  One, known as the zoo hypothesis, suggests that Earth is a giant zoo for aliens to watch and study us, which is why we haven’t seen them.  Another suggests that we are actually in a simulation developed by aliens to study us.

These are all interesting ideas; the problem with this particular paradox is that it is basically impossible to test any of these hypotheses right now.  We lack the technology and understanding of the world to evaluate these hypotheses in a scientific manner, so for now we are forced to simply speculate.

Works Cited

History of Life: Origins of the Earth

The Earth has existed for around 4.5 billion years, and much has happened in its history to shape and create the Earth we know today.  But what exactly happened up until the origin of life?

4.5 billion years ago, the Earth was formed, along with the Sun.  The Earth was probably created by aggregating of dust and rocks, forming one of four terrestrial, rocky planets in our Solar System.  During this period of early Earth, the surface was incredibly hot, not even quite cooled to the point that the rock at the surface was completely solid.  The Earth took a while to cool down, because it was continuously bombarded by other rocks in space, which kept temperatures high and prevented surface rocks on Earth from solidifying and any water from remaining in liquid form.  These bombardments also released gases that accumulated into an atmosphere, mainly consisting of carbon dioxide and carbon monoxide.

Once this bombardment stopped, Earth’s surface temperature cooled down, the rocks at the surface solidified, and this allowed liquid water to remain at the surface, eventually forming oceans, around 4.4 billion years ago.  After this, life may have formed between 4.4 and 3.9 billion years ago, but any traces of that life would have been wiped out by the Period of Late Heavy Bombardment, a period around 3.9 billion years ago when asteroids began to collide with Earth (and most of the inner planets) continuously.  This also most likely evaporated the liquid water on Earth.  After this period ended, Earth solidified again and accumulated oceans, setting the stage for the origin of life.

Geological time scales; found at

Looking at the above official geological timeline, the time we are talking about is in the Hadean Eon, the earliest time period in Earth’s history.  Life begins in the Archaean eon, so named because the original life on Earth came in the form of single-celled organisms called Archaea.

In the next post, we’ll talk about the origin of life, why Earth was the “best” planet in our Solar System to develop life, and Fermi Paradox: why haven’t we found extraterrestrial life?

Works Cited

History of Life, 5th edition, Richard Cowen

Microcosmos: Four Billion Years of Microbial Evolution, Lynne Margulis and Dorion Sagan

Smithsonian Natural History Museum,

A Few Science Books That Will Change How You Think

As the year 2014 is winding down, now is an excellent time to start picking up some new books!  Maybe it was your New Year’s Resolution to read more and you’ve procrastinated until now, or maybe you just feel like reading some more now.  Either way, I want to dispel the myth that scientific nonfiction books are not a fun use of your time.  There are some books out there that are fast-paced, exciting, and informative – you just have to know how to find them.  Here are a few science books that fit this description:

The Signal and the Noise: Why Most Predictions Fail – but Some Don’t by Nate Silver

You may know Nate Silver by his blog FiveThirtyEight, which has received a lot of praise for its political predictions.  However, as a statistician, he knows a lot more than just politics – and he shares it all in this book.  The book describes how people make predictions – about everything from politics to the weather – and what went wrong when these predictions fail.  The great thing about this book is that it has something for everyone; in each chapter he explores a different area of study that requires predictions and explains the successes and failures in that field.  He does a few chapters on economics, one on baseball, one on earthquakes, another on hurricanes, and one on weather and the climate.  And each chapter is engaging and informative, and we learn one major lesson: we really shouldn’t complain about weather forecasts so much.

Microcosmos: Four Billion Years of Microbial Evolution by Lynn Margulis and Dorion Sagan

The Earth has been around for four billion years (a bit more, actually) and a lot of its history has been dominated by microorganisms: single celled life that provided the basis for all other life on Earth.  In this book for those interested in biology, geology, and paleontology, Margulis and Sagan explore the vast reaches of the microbial world, beginning with when the Earth formed.  They describe how microorganisms created an atmosphere safe for other life to form, how they colonized the entire world through communication and connections with other bacteria, and gave rise to other life.  This book really makes you think differently about single-celled life and our importance in the world.

Proofiness: How You’re Being Fooled by the Numbers by Charles Seife

I’ve mentioned this book many times in previous posts, but I am going to make one more reference because this book definitely changed how I think about the world.  Seife makes one main argument in this book: that a lot of people in the world use mathematics to deceive or manipulate the public, and it is important to develop certain skills to recognize and combat this.  However, the genius of this book is the numerous examples he gives – everything from advertising companies to the United States Supreme Court – to back up his claims.  The next time you are fed a number, you will stop to think where that number came from.

A Short History of Nearly Everything by Bill Bryson

If you are someone who just wants to know everything, this is the perfect book.  Bill Bryson describes the basics of chemistry and physics (how large the universe is, the concept of an atom, etc.) as well as going into the history of life through geological and biological discoveries.  He also discusses problems facing us today, including the climate and the possibility of large space bodies coming into contact with the Earth.  He mixes the scientific knowledge with descriptions of the scientists and experiments behind these discoveries, making for a book that is informative and easy to read.

If you have read any science-related books that you think others would like to read and are willing to write up a little blurb about it, I’m happy to post it on the blog or the Facebook page!  Just email me at!

What Happened At Chernobyl?

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Photo taken by Justin Stahlman, Found at:

Chernobyl is known as one of the biggest mistakes and explosions at a nuclear power plant…but what really happened?  And could it happen again?

For more information on how nuclear power plants work before reading this, check out the other post on how nuclear power works:

The Chernobyl reactor was an RBMK reactor, a rare type of reactor that is unique because it is cooled by coolant water and also moderated by graphite – a combination that isn’t found in any other reactors.

On the day of the explosion, the reactor was set to be shut off just for maintenance.  Some electrical engineers decided to run a test to see if power was cut to the reactor, the turbine could keep running long enough to continue pumping coolant water until a generator kicked in.  The test required the power to be dropped to about 700 megawatts.  However, due to miscommunication and demand for electricity, the power was not dropped as fast as scheduled, so by the time that the reactor was running on enough power to run the test, it was already late.  The engineers tried to drop the power too low too quickly, causing xenon poisoning of the reaction, which made them unable to raise the power to the required 700 megawatts.  To speed up the power increase, they withdrew the control rods (that help control the reaction by absorbing neutrons) to less than the minimum amount.  They raised the power to 200 megawatts and carried out the test at that power level.  Unfortunately, due to the test, the emergency core-cooling system had been shut off.

So, they began the test by shutting off the water pumps that deliver coolant to the reactor.  This caused the water at the core to boil, turning into steam.  The water is supposed to be there to absorb neutrons, stabilizing the reaction.  However, when it turns into steam, it does not absorb neutrons as well, meaning the reaction could runaway much easier.  This caused the power to rise above 500 megawatts very quickly.

The engineers at this time realized something was wrong and immediately lowered all 200 or so control rods into the reaction at once.  These control rods, however, were made with graphite at the tip, which, when inserted into the reactor, caused the reaction to increase out of control.  At this point, the reactor exploded, most likely due to steam buildup.  It’s important to note that this was not a nuclear explosion; it was caused by pressure of gases.

This was a tragedy created by many problems, including design flaws in the reactor itself and miscommunication and misinformation during the test and shutdown of the reactor.  Could it happen again?  It’s very unlikely, given that reactors are much more carefully designed now all over the world to avoid this particular type of problem.

Works Cited—Appendix-1–Sequence-of-Events/

Climate Change: Is There Really a Connection Between Hurricanes and Climate Change?

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Hurricanes, as we have seen in the past few decades, have the potential to cause a lot of damage – which is why it is particularly concerning when scientists suggest that climate change could actually exacerbate these storms.  Why is this?

First, we have to look into how hurricanes are formed.  Hurricanes are always formed in warm, tropical regions, because they use heat.  The warm water from the topical regions of the ocean evaporates, turning into warm water vapor, which rises and creates a cloud, and more warm water vapor rises to replace it.

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The above picture shows the water vapor as it rises, starts to cool and condense into clouds, and then fall as more warm air replaces it.  This creates a spinning of the winds which is the main identifiable characteristic of hurricanes.

The more heat is in the water, the more water can rise, the bigger these clouds get, and the faster the winds spin – therefore, the stronger the hurricane gets.

There has been conclusive scientific evidence suggesting that climate change could greatly exacerbate tropical storms, monsoons, and hurricanes.  We have actually seen storms increase in magnitude over the last few decades.  However, the next question is – would it cause more of these storms?  Logically, it would make sense, because if the oceans are warmer all the time, then the storms should form more often.  However, the winds have to be directed a certain way and other factors are at play, so currently there is not a consensus of evidence suggesting that climate change could cause more storms – but scientists are still looking into it and still uncovering evidence.

Works Cited