deletions | additions       diff --git a/introduction.tex b/introduction.tex  index 298273e..820b798 100644  --- a/introduction.tex  +++ b/introduction.tex 
...
\section{Introduction}   The work presented here is the result of a serendipitous encounter between researchers involved in two independent projects that were winners of an a ISS Research Competition hosted by Space Florida, and launched to the International Space Station as part of the payload on the SpaceX CRS-3 mission, which launched from Cape Canaveral on April 18, 2014. The goal of Project HEART FLIES was to examine the effects of microgravity on the heart development and function in five strains of \emph{Drosophila melanogaster}, including three normal strains and two mutant strains that are predisposed to heart malfunction. Upon return to the Earth's surface, these flies were dissected to assay heart function, morphology, and tissue-specific gene expression. Ground-based control populations were assayed at the same time. One of the goals of Project MERCCURI was to examine the growth kinetics of several bacterial strains that were collected from the surfaces of various public built environments throughout the United States, including sporting venues and national monuments. A second goal was to examine the microbial communities inhabiting various surfaces within the International Space Station, using DNA-based censusing techniques.  The  fruit fly \emph{Drosophila melanogaster}, has a storied history of over a century as a model organism for genetic and behavioral studies. In more recent decades, it has also been used as a model organism for immune system and cardiac function, and it is emerging as a model for host-gut microbiome interactions. While Drosophila cardiac anatomy is quite different from that of a human, it does share some functionality (e.g., ion channels) and many of the genes involved in building a heart are shared between flies and humans. As in humans, cardiac function declines over the life span of the fly \cite{Ocorr_2007}. However, the typical lifespan of a fly is 45-60 days, allowing for quick study of age-dependent decline in organ function. \emph{Drosophila melanogaster} has also been a frequent flier to low Earth orbit, where it has been used to study the effects of spaceflight and microgravity on innate immunity \cite{Taylor_2014} \cite{Marcu_2011}, DNA mutation \cite{Vaulina_1982}, and development \cite{Marco_1992} \cite{Abbott_1992}.  \emph{Drosophila melanogaster} has also been a frequent flier to low Earth orbit, where it has been used to study the effects of spaceflight and microgravity on innate immunity \cite{Taylor_2014} \cite{Marcu_2011}, DNA mutation \cite{Vaulina_1982}, development \cite{Marco_1992} \cite{Abbott_1992}  As in humans, cardiac function declines over the life span of the fly. However, the typical lifespan of a fly is 45-60 days, allowing for   Transient adult microbiota, gut homeostasis and longevity: Novel insights from the Drosophila model. \cite{24983497}