Muscles are capable of providing an amazing amount of stability to the spine; a normal human spine can experience compressive loads of up to about 1,350 pounds during more demanding everyday tasks (9), and almost 4,000 pounds during something like Olympic weightlifting (2).

So why can you hurt your back just by bending down to pick up a pencil or pen?

The simple answer is that spinal stability is not a simple function of muscular force.

One way to think about spinal stability is that it is made up of three different components: the spine itself, the muscles surrounding the spine, and the circuitry that is in charge of firing these muscles (11).

The neural control unit is the circuitry that coordinates the muscle activity to respond to both expected and unexpected forces. For appropriate spinal stability, this system must fire the right muscles, at the right time, by the right amount, to protect the spine from injury while still allowing the desired movement (1). The muscles surrounding the spine are like the "rigging on a ship's mast," and as such an inappropriate magnitude from just one of them could perturb the fine balance of the mast (10).

STOP! Don't pick up that pen!

Most people probably think of change when they hear the word evolution, but some of evolution's most amazing molecular inventions have stuck around hundreds of millions, even billions of years. The complex protein machinery needed to express genes, metabolize energy sources, reproduce sexually, and lay out body plans has remained in place largely unchanged in spite of the tremendous variety we see in the living world. These constant core cellular processes are why biologists could crack the universal genetic code by experimenting with bacteria, and why we gain insight into cell division and cancer by studying yeast.

The big question, argue the authors of The Plausibility of Life, is not how evolution keeps inventing new genes - it's how evolution can produce so much variety when the basic processes change so little. Later in the book Kirschner and Gerhart are going to argue that these basic systems have persisted so long because they are versatile, that they posses features which make them well-suited to facilitating the biological diversity we see today. We'll come to that argument later; today we'll take a closer look at the core conserved molecular systems that carry out the most basic cellular functions.

Scientific happenings, big and small, on this day in history…

But first, today’s quiz:
What event, which took place on this day in 1883, produced the most violent explosion known in human history? You probably know the answer; it’s just a matter of thinking about it for a moment. But just to be sure, you can check the answer at the end of the article.

And on to other historic happenings…

A group of researchers at the Nuclear-Magnetic Resonance unit at the University of Warwick in the United Kingdom has come one step closer to understanding how BioGlass can give you bionic bones.

Bioglass is a synthetic material that dissolves in the body, releasing calcium which stimulates the growth of new bone cells. New forms of bioglass are revolutionizing the way we look at bone disease and fractures.

I usually limit my book reviews to Goodreads or Shelfari but this one deserves much more attention.

It was two years ago that I first wrote about ocean dead zones. These are areas of the ocean that, due to a lack of oxygen, no longer sustain any life. While dead zones can happen naturally, they usually are caused by the results of human activity. A primary cause is nitrogen-rich nutrients from agricultural fertilizers that flow into coastal waters from rivers and streams.

Last week there was a report published in the Journal of Science that stated that the number of these ocean dead zones around the world has doubled every decade since the 1960s. There are now some 400 coastal areas that periodically or perpetually become dead due to oxygen starved bottom waters.

Five years ago, Edith had a problem: Her goldfish of 25 years, Mr. Fish, had dropsy, a disease characterized by a swollen or hollow abdomen and in most cases fatal. In her last attempt to save her pet, on a whim, Edith wrote a message on GoldfishConnection asking for help.

Rick G. Copeland, the specialist at the goldfish site, recommended some Medi-Gold pellets. Two years later, at age 27, Mr. Fish swam around his tank as if his close call with death never happened.

Mr. Fish may not have the 49 year-old record of the oldest goldfish ever, but he's working on it. In the meantime, Mr. Fish is competing with the millions of other pet goldfish around the world.

Misinterpreted fragments of leg bones, teeth and brow ridges found in Palau appear to be an archaeologist's undoing, according to researchers at three institutions. They say that the so-called dwarfs of these Micronesian islands actually were modern, normal-sized hunters and gatherers.

Scientists from the University of Oregon, North Carolina State University and the Australian National University refute the conclusion of Lee R. Berger and colleagues that Hobbit-like little people once lived there.(1)

"One of his biggest mistakes was rushing to publish," said University of Oregon anthropologist Greg C. Nelson of Berger. "He did not take the time to understand the area in which he was working -- its entire history, not just the skeletal stuff," he said. "Any time you work anywhere, you have to understand this history. You just can't walk in and cowboy it, pull some stuff out and draw conclusions in the absence of understanding the bigger picture."

The popular phrase, "I have nipples, Greg, could you milk me?" from the 2000 movie "Meet the Parents", is similar to the widely held belief that tomatoes, because of their seeds, are really fruits instead of vegetables.

Botanically, tomatoes are fruits but cucumbers, zucchini, pumpkins, nuts, corn, peppers, peas, and other vegetation that may not seem like it also fit into this fruity category.

Botanists define fruit as any part of a plant that contains both its seed and the ovary that produce that seed. However, of all the botanically fruity plant pieces we commonly call 'vegetables', tomatoes are one food with an especially controversial history of classification.

The geysers of Yellowstone National Park owe their existence to the "Yellowstone hotspot", a region of molten rock buried deep beneath Yellowstone, geologists have found, but how hot is this "hotspot," and what's causing it?

In an effort to find out, Derek Schutt of Colorado State University and Ken Dueker of the University of Wyoming took the hotspot's temperature. They published results in the August, 2008, issue of the journal Geology.

"Yellowstone is located atop of one of the few large volcanic hotspots on Earth," said Schutt. "But though the hot material is a volcanic plume, it's cooler than others of its kind, such as one in Hawaii."

A 75-million-year-old fossil of a pregnant turtle and a nest of fossilized eggs that were discovered in the badlands of southeastern Alberta by scientists and staff from the University of Calgary and the Royal Tyrrell Museum of Palaeontology are yielding new ideas on the evolution of egg-laying and reproduction in turtles and tortoises.

It is the first time the fossil of a pregnant turtle has been found and the description of this discovery was published today in the British journal Biology Letters.

The mother carrying the eggs was found in 1999 by Tyrrell staff while the nest of eggs was discovered in 2005 by U of C scientist Darla Zelenitsky, the lead author of the article and an expert on fossil nest sites, and her field assistant. Both were found about 85 km south of Medicine Hat in the Manyberries area.

New research suggests that preventative agents, such as those found in concentrated black raspberries, may more effectively inhibit cancer development than single agents aimed at shutting down a particular gene.

Researchers at the Ohio State University Comprehensive Cancer Center examined the effect of freeze-dried black raspberries on genes altered by a chemical carcinogen in an animal model of esophageal cancer.

The carcinogen affected the activity of some 2,200 genes in the animals' esophagus in only one week, but 460 of those genes were restored to normal activity in animals that consumed freeze-dried black raspberry powder as part of their diet during the exposure.

A powerful collision of galaxy clusters has been captured with NASA's Chandra X-ray Observatory and Hubble Space Telescope. Like its famous cousin, the so-called Bullet Cluster, this clash of clusters provides striking evidence for dark matter and insight into its properties.

Like the Bullet Cluster, this newly studied cluster, officially known as MACSJ0025.4-1222, shows a clear separation between dark and ordinary matter. This helps answer a crucial question about whether dark matter interacts with itself in ways other than via gravitational forces.

There is a great deal of concern about the effects of global warming on the Greenland ice sheet but scientists at the University of Bristol and the University of Leeds have taken the discussion to a deeper level - namely in stating that only changes in atmospheric carbon dioxide are able to explain the transition from the mostly ice-free Greenland of three million years ago to the ice-covered Greenland of today.

CO2 drops caused Greenland to become ice-covered so CO2 gains could undo that, they say.

There are several competing theories, ranging from changes in ocean circulation, the increasing height of the Rocky Mountains, changes in the Earth's orbit, and natural changes in atmospheric greenhouse gas concentrations. Using state-of-the-art computer climate and ice-sheet models, Dr. Dan Lunt from the University of Bristol and colleagues decided to test which, if any, of these theories was the most credible.

Not all fat is created equal, it seems. A Temple University study finds fat in obese patients is "sick" when compared to fat in lean patients.

Why 'sick? When our bodies don't work properly, we say we're sick. The study in the September issue of Diabetes finds that the same could be said for fat tissue found in obese patients. The cells in their fat tissue aren't working properly and as a result, are sicker than cells found in lean patients' fat tissue.

Lead author Guenther Boden, M.D. theorizes that "sick fat" could more fully explain the link between obesity and higher risk of diabetes, heart disease and stroke.

The latest research into dual-purpose contraceptives and non-hormonal contraception will be presented at the annual scientific conference of the Society for Reproductive Biology (SRB) conference in Melbourne.

University of Newcastle Laureate professor John Aitken, a world-leader in reproductive biology, will discuss the need to develop novel, safe, effective, dual-purpose contraceptive agents that combine the prevention of pregnancy with protection against sexually transmitted diseases (STDs). His research has explored the development of a contraceptive agent that immobilises – but does not kill – sperm. The agent also possesses microbicidal activity simultaneously reducing the risk of infection with sexually transmitted diseases, such as Chlamydia.