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Jeff Danner

West Nile Virus

So far in 2012 in there have been over 1000 reported cases of West Nile Virus in the U.S. which have resulted in over 40 deaths.  The graphic at the top of the page from the CDC shows the locations of the confirmed 2012 cases through August 28.  The news reports I have read thus far on West Nile Virus have been uniformly insubstantial.  They discuss the statistics of the outbreak, whether there have been any local cases or deaths while leaving the question of what it means for a new endemic disease to have entered the U.S. entirely...

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The Science Behind WCHL, Your News, Talk, and FM Station

Tuesday, August 28, 2012, is a big day for WCHL with the launch of FM broadcasting on 97.9. To honor this new phase in the station’s history, here is your Common Science® review of AM and FM radio waves.   Let’s start with some of the basics and talk about waves.  If you throw a stone into a pond, it generates waves on the surface of the water which move out in all directions.  The waves can be described by their height (the amplitude) and the distance between the peaks (the frequency).  As the waves move away from their source they begin to lose coherence and, eventually, fade away.  Try to keep this image of a wave in a pond in your head as I discuss radio waves below.   Radio waves are the name we give to the lower range of the energy spectrum of electromagnetic radiation.  Other energy ranges of the electromagnetic spectrum include infrared radiation, light, ultra-violet radiation, microwaves, X-rays, and gamma radiation.  Electromagnetic waves travel through space in a manner analogous to waves in a pond in that they can be described by their amplitude and frequency and lose strength and coherence at they travel.  (For more detail on electromagnetic radiation, read my earlier column, “Is Your Cell Phone Trying to Kill You?”)     Radio stations generate radio waves by applying alternating electric current...

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Marriage Advice from Common Science

This week I am taking a detour from my usual topics and providing a bit of life advice.  Want to get married?  Find yourself a chemical engineer.  (Full disclosure for first time readers, your humble author is a chemical engineer himself.)   If you want to determine the “divorce rate” in the U.S. and assume that this would be an easy figure to locate, you would be mistaken.  The problem does not stem from a lack of data but rather from the fact that “divorce rate” does not have a uniform definition.  You can find data quoting divorces per year per 1000 adults, divorces per year per married adult, divorce data as a function of age at marriage, and whole host of other measures.  To muddy the waters even further, those who write about divorce rates rarely tell you which definition they are using.   From my point of view the most meaningful definition of divorce rate is the percentage of marriages which end in divorce rather than by the death of a spouse.  The percentages of first, second, and third marriages which end in divorce in the U.S. are 41%, 60%, and 73%, respectively.  In aggregate these rates result in an overall value of 50%.   You can find many studies which examine divorce rates for people in different professions.  Irrespective of which definition is used, chemical engineers...

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Don't Let the Bed Bugs Bite

Good night, sleep tight, Don’t let the bedbugs bite. And if they do Then take your shoe And knock ‘em ‘til They’re black and blue! Old English Nursery Rhyme (~1860) – Author Unknown   Among the list of things that give us the creeps, bed bugs are near the top.  If you think learning about bed bugs will keep you awake at night, stop reading now . . .     Bed bugs are light brown to brown insects which grow to be approximately ¼ of an inch long.   Although not exclusively nocturnal, they tend to hide in dark crevices during the day and feed at night.  They are attracted to heat and carbon dioxide and they feed on blood, making a warm, exhaling, sleeping human quite an appealing buffet.  A bed bug feeds by inserting a straw-like proboscis into your skin and sucking out blood for about five to ten minutes.  The feeding process is not particularly noticeable such that most people sleep right through it.  Their bites cause rashes and allergic reactions as well as quite a bit of psychological angst.  Fortunately, unlike other insects which feed on our blood like mosquitoes or ticks, bed bugs do not spread disease from person to person.    People often remark on the resilience of the cockroach, but the bed bug deserves some accolades in this category as well.  While a...

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When the Lights Go Out

As I write this, 600 million people in India – approximately twice the population of the United States – are in the midst of the most extensive power outage in the history of the world.  Take a moment and consider the chaos that would occur here in the U.S. if the entire country lost power for the day.  As I have been reading the news accounts about this crisis, I have been trying to investigate how this could have happened and whether it could happen here.    As usual, lets start with some background.  Electrical power grids have three main components: generation, transmission, and distribution.  I previously covered the basics of generation in “Electricity Production 101.”  Transmission is carried out through the overhead wires you see everywhere as well as in underground cables.  The electricity in these wires is delivered from the power plants at a higher voltage than is required by the end user. Distribution is managed by transformers located near to the end user, which reduce the voltage to the appropriate level.  In your house this is typically 220 volts for electric clothes dryers or ovens and 120 volts for everything else.   For an electric power grid to operate in a stable way the supply from power plants and the demand from end users needs to stay extraordinarily well balanced.  When supply and demand get out...

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To Frack or Not to Frack

I am on vacation this week, so we are running a “Best of Common Science.”  The NC Legislature’s overide of Governor Perdue’s fracking ban means that the process of designing the regulatory framework for fracking will begin in earnest. I am in the initial stages of what will be my fourth column on fracking to address the challenges of designing these regulations.  The first challenge will be to define exactly what fracking is.  This may be a bit more challenging than it sounds since nearly all forms of drilling involve the injection of fluids into ground.  In addition, a...

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Welcome to the Greenhouse

I am on vacation this week, so we are running a “Best of Common Science.”  Something interesting is occurring in the scientific community in the response to the heat waves and droughts which are sweeping the country this summer.  In years past, the response of the scientific community to extreme weather has been along the lines of “We can’t attribute any isolated event spefically to global warming”.  It appears now that the accumulated evidence has reached the point that scientists have become more comfortable in attributing global warming as being directly related to weather this summer.  To help you sort through some of the news coverage on this topic, we are re-posting “Welcome to the Greenhouse”. Before we used to talk about Climate Change or Global Warming, the term Greenhouse Effect had center stage. The engineer in me misses those days. The US political landscape (at least a portion of it) is littered with science-adverse representatives and candidates who say things like “global warming is hoax”. I invite you to Google “Michele Bachmann global warming” for some examples. If we had stuck with the term Greenhouse Effect, the job of the science-denying politician would have been made much more difficult. Let me try to explain.   The sun bathes the earth in electromagnetic radiation (See my column “Is Your Cell Phone Trying to Kill You” for more information on electromagnetic radiation) with most of the...

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Don't Sweat It

Last week I spent three peaceful and fantastic days volunteering at the Festival for the Eno.  The weather was steamy with high humidity and temperatures flirting with 100 oF.   In the course of delivering drinks and ice to hot and thirsty people, I got into a conversation about sweat with my fellow Drink Booth Coordinator, Chip Gentry, and the outline for this column just sort of popped into my head.   Your body has a regulation system designed to keep your core temperature at 98.6 oF.  When your body gets too cold it converts energy stored in your cells into heat and increases body movement through shivering.  When your body gets too hot you sweat.  Sweating removes heat from your body when the liquid water on your skin evaporates, carrying away the energy required to vaporize it.   Even when you are sitting still your body is generating heat through normal metabolic processes.  Therefore, in order to maintain its normal temperature, your body must reject heat into the surrounding air.  Movement or exercise increases the amount of heat generation within the body, thereby increasing the amount of heat which must be removed to maintain body temperature.  Whenever your body can’t reject sufficient heat to the air through normal heat transfer mechanisms, including conduction, convection, and radiation, you sweat.    The discussion above can be summarized by the following heat...

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The God Particle

July 4th, 2012, was a significant day in the history of science.    In a news conference in Geneva Switzerland, physicists at the Large Hadron Collider – a 16 mile long particle accelerator where matter is smashed together in an attempt to recreate conditions which existed fractions of a second after the Big Bang – announced that, after a 30+ year search, they have confirmed the existence of the Higgs boson.  This is a really big deal.  As I will explain, there is a reason the Higgs boson has acquired the nickname the “God Particle”.  As usual, the mainstream media coverage on this dumbs down the science when reporting this story, assuming that the reader cannot possibly understand.  This is just the type of gap in news coverage that I try to fill here in Common Science®.  So fasten your seat belts and return your tray tables to their full, upright, and locked positions as we embark on a journey into particle physics.   To understand why the discovery of the Higgs boson is so important, we need to start with a review of the structure of matter and a summary of the Standard Model of physics.    Early on in high school chemistry you were taught that atoms were made up of protons, neutrons, and electrons.  Then most of the remainder of the course focused on the interactions of atoms. ...

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Don't Know Much Biology

My oldest child enters high school this fall and, like most freshmen, will be starting her sequence of science classes with biology. From my perspective biology is not the logical starting point for high school science and it is time to reevaluate the entire science curriculum.   First, we need to ask ourselves “why do we teach our children science?”  In my opinion there are two reasons: to produce enough scientists and engineers to maintain our economic well being, and to create citizens who can think for themselves rather than be vulnerable to the siren calls of charlatans and demagogues.   Let’s first consider the goal of encouraging children to consider science as a career.  In this case you want to ensure that they have both a strong foundation in the sciences and that the sequence of classes builds towards an interesting crescendo that will inspire many of them to choose a science as a college major. This would entail teaching chemistry and physics in the 9th and 10th grades.  Chemistry teaches you about the interaction of matter and physics covers the fundamental forces which govern the universe.  All other sciences proceed from this common foundation.   Once you’ve got a handle on the basics of chemistry and physics, it’s time to move on to more complex systems such as a living organism (biology), ecosystems, weather, or the universe. ...

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