Of the 5 million Americans who play football in a given year, 3.5 million of them are children ages seven to 13. Despite this, little is known about the effects of the constant head-to-head impact players frequently incur during a typical game. But Stefan Duma, a biomedical engineering professor and researcher at Virginia Tech University, is beginning to shed light on this mystery.

Duma discussed his recent research on concussions in young football players and his new ranking system for football helmets this past week, as part of the UC Davis biomedical engineering department’s Distinguished Seminar Series.

As Duma explained, concussions are often a hidden injury. Unlike other injuries such as breaking an arm or tearing a muscle, a concussion will not always show outward symptoms, even though the damage inside can be very severe. Further, it’s not a type of injury that forces a player off the field like a broken arm does, and players never want to leave the game.

“Nobody knows exactly what a concussion is. A hit that knocks one player down may cause another player to just shake off,” Duma said at his lecture last Thursday. “What we do know is the higher the acceleration of the impact, the more likely you are going to have a concussion.”

Over the course of one season, the Virginia Tech football team, the Hokies, wore helmets outfitted with impact sensors to measure the amount of forces sustained by players during head-to-head impact, both in practice and during games.

Duma did the same analysis on youth football, children aged seven to eight years old, at a local football league near the university. He later expanded his study to multiple college football teams and high schools.

Duma and the other researchers were surprised by the data they received. They found that many of the impacts that children endured were at the same level as those suffered by college players. This finding, as Duma explained, is very concerning, not only because that amount of impact is known clinically to cause concussions but also because the effect of this impact on developing brains is unknown.

“It shows that concussions have been underreported. Based on this we want to better understand head impact in children and develop methods to better identify injuries,” said Steve Rowson, an assistant research professor at Virginia Tech and co-author of the study.

The study also revealed that the majority of the high impacts were incurred during practice, rather than during the actual games. This finding could potentially cause coaches to rethink practice methods.

“These kids are already in great shape. They don’t necessarily need to have constant head-to-head impact to get better,” Duma said.

Based on this research, Duma and his team have come up with a five-star ranking system for football helmets, which they believe are at the root of the problem.

“Prior to this, helmets had never been ranked. They were either considered safe or unsafe,” Rowson said.

Much like the five star ranking system in a car, this system tells how well a helmet will perform during a head on collision. Surprisingly, they found no correlation between cost and helmet performance.

In fact, as Rowson noted, “one of the cheaper helmets was actually a four star helmet.”

Duma and his researchers believe this new ranking system, paired with further research to understand how exactly these young players sustain their head injuries, will significantly improve the safety of football.

CLAIRE MALDARELLI can be reached at science@theaggie.org.

It’s March, and that means that it’s Apple time. Just like with the iPad 2 last year, Apple has once again chosen March as the month to reveal its newest iPad version. Interestingly, Apple has not named the newest iteration, iPad 3; instead, it’s just being called the new iPad. It certainly has some new features, but whether it’s worth a purchase will depend on the buyer’s tablet history.

How does it compare with the iPad 2?

The biggest difference between the two iPads seems to be the screen resolution. The new iPad’s screen resolution is 2048×1536 at 264 pixels per inch, while the iPad 2’s resolution is half of that. This makes the display of the new iPad the best resolution of any current tablet.

What other specifications are important about the new iPad?

Apple claims that the A5X processor is capable of a graphics performance four times greater than NVIDIA’S Tegra 3 chip, which can be found on many Android tablets. The new iPad will also have a new quad-core graphics processor, which will make playing games on the iPad look even better, and will support 4G LTE for faster networking.

Anything else?

The new iPad has a 5-megapixel rear-facing camera that can record video in 1080p, an improvement over the iPad 2’s 0.7-megapixel camera which only captures video in 720p.

So, what’s the price?

The basic new iPad 16GB model starts at $499 and is available in black or white. The price goes all the way up to $829 for the new iPad with 64GB of memory and 4G. The iPad 2, by comparison, is now $399.

It all comes down to how much you want the latest technology, but iPad 2 owners should most likely be content to stay with last year’s version. While the upgrade in screen resolution is eye-catching, all of the other upgrades seem to be similar to the jump from the iPhone 4 to the iPhone 4S — relatively incremental in comparison.

ERIC C. LIPSKY can be reached at science@theaggie.org.

Researchers have made important new discoveries about the evolution of the senses in animals by identifying a light-based, or “photic,” sense in a multicellular marine animal called hydra.

The discoveries are reported in a new article in the journal BMC Biology, written by David Plachetzki, who is currently a post doctoral fellow working in the UC Davis Center for Population Biology, along with two co-authors from UC Santa Barbara, Caitlin Fong and Todd Oakley. Plachetzki is also affiliated with the UC Davis department of evolution and ecology.

“By combining genomic and physiological approaches we now have powerful tools to unravel these first steps in the evolution of a nervous system,” said Thomas Holstein, a professor of molecular evolution and genomics at the Centre for Organismal Studies in Heidelberg, Germany, who was not involved in the current study.

Plachetzki and his research colleagues asked questions about the common ancestor of cnidarians and humans, which existed 600 million years ago.

“This is the origin of complex ‘animal-ness’ — that’s not the first animal, but the first one that has a nervous system and moves around,” Plachetzki said.

Cnidarian (pronounced “naye-DARE-ee-en” with a silent “c”) animals include hydra, jellyfish and sea anemones, among other animals, and are evolutionary cousins to humans.

“Dave [Plachetzki] had noticed that visual proteins were located around the stinging cells in hydra,” said co-author Fong, who is a member of the research team and is now a lab technician at UC Los Angeles. “This led us to believe that hydra used visual signals to regulate the usage of these stinging cells.”

“We devised behavioral tests to be the first to show that stinging cells depend on light level,” said Oakley, a professor in the department of ecology, evolution and marine biology at UC Santa Barbara.

One of the main findings of the study was that hydra are more likely to fire their stinging cells when a shadow is cast onto them, which increases their chances of catching the possible prey casting the shadow.

“Hydra fire more stinging cells in dim light conditions and less in bright light conditions,” Fong said . “We think that this is a method by which hydra conserve stinging cells and only fire them when they might catch prey.”

Hydra are freshwater polyps, which are small relatives of jellyfish, that have been studied for over 250 years. Although they don’t have eyes, Plachetzki’s research shows how a physiological pathway could function which was a precursor to vision in later animals.

“This is one way that those pathways could function before they got co-opted into a complex eye,” Plachetzki said .

The animals that developed vision in later evolution were “putting together pieces that have already evolved,” Plachetzki said.

There are three main ways that animals detect sensory cues from the environment: chemical, mechanical and photic. The current study focused on the photic, or light means of sensation. The chemical category corresponds to the sense of “taste” in animals, while the mechanical category roughly corresponds to touch and hearing.

Holstein is currently studying dinoflagellates, a type of plankton, in his lab in Heidelberg and says that Plachetzki, Fong and Oakley’s new research findings raise new questions as to whether a mechanical sense or a photic sense developed first in common ancestors of animals and plants.

“This is difficult to decide at the moment,” said Holstein, commenting on the lack of evidence one way or the other. “We just don’t know enough [about the] huge diversity in unicellular organisms.”

BRIAN RILEY can be reached at science@theaggie.org.