Roundup of Recent Science Discoveries, 2001
The Fog at the Beginning of the Universe
A team of astronomers from the California Institute of Technology, led by S. George Djorgovski, may have glimpsed the dawn of our universe. In Aug. 2001, this team reported that it had spotted the ?cosmic renaissance,? the era when the first starlight shone through the cosmos. Just days earlier a team from the Sloan Digital Sky Survey had announced finding evidence of the cosmic ?dark ages??the period of about half a billion years after the Big Bang when dark fog filled the newly created space of our universe. The cosmic renaissance brought an end to the dark ages, as the first galaxies and quasars burned through the murky cosmos, making it transparent.
The teams used data collected with powerful telescopes to observe the light emissions of quasars, the most distant known objects in the universe. Quasars, which are amazingly bright, can essentially offer snapshots of the universe from hundreds of millions of years ago. The Sloan team observed fog around a quasar that they believe began shining just as the dark ages were drawing to a close. The quasar studied by the Djorgovski team was slightly closer and glowed more brilliantly; it had probably sent forth its light after the fog began to dissipate, some 100 million years later.
Astronomers estimate that the cosmic fog started to burn away about 900 million years ago. For decades they had been searching for proof, but until this time had not been able to collect data from distant enough objects.
The Titanosaur from Madagascar
The skeleton of a new species of titanosaur, a common type of plant-eating sauropod, was found in Madagascar in July 2001 by American scientists Catherine Forster and Kristina Curry Rogers. The titanosaur is one of the least understood dinosaurs, though its fossils have been found on nearly every continent. The Madagascar find is significant because the titanosaur's skull and skeleton were both well preserved, offering scientists their first head-to-tail look at this type of dinosaur. Until now, only partial skeletons had been found in Madagascar and Patagonia, and no complete skull has ever been discovered. Although more than 30 types of titanosaur have been recognized, poor fossil records have left scientists unable to adequately compare these species.
The titanosaur's skeleton was relatively flexible and light, which permitted the long-necked 50-foot quadruped to manage its enormous size. As a result, its fossil bones broke easily and disintegrated, making it a poor candidate for preservation.
As Plain as the Nose on Its?Face?
Paleontologists from the ?DinoNose Project? have confounded a couple of centuries' worth of thinking about the location of dinosaurs' noses. Since the 19th century, artists' renderings?based on paleontologists' conceptions?have shown the nostrils drawn on the top of some dinosaurs' heads. This position was thought to be accurate for semi-aquatic dinosaurs such as Diplodocus, but recent findings maintain that the nostrils for both aquatic and land-locked lizards are in fact right above the mouth. The size of the nasal cavity is also believed to be far larger?up to half the volume of the dinosaur's skull. Ohio University's Dr. Lawrence Witmer, paleontologist and the study's author, researched the skulls of more than 60 distant dinosaur relatives living today and found that all shared common nostril placement and function. The soft-tissue markings on these skulls compared favorably with the soft-tissue markings on dinosaur skulls. ?We looked at as many modern-day animals as we could get a hold of,? Witmer said, ?and found an extraordinary amount of evidence to suggest the nostrils of dinosaurs actually were parked out front.?
This isn't the first time that Witmer's research could change how we imagine dinosaurs. In 1998, he ripped the lips from Tyrannosaurus rex by reporting that the movie snarler did not in reality have the correct facial bone structure for lips.
One of the most politicized science issues of 2001 was the federal funding of stem-cell research to find treatments for human diseases. Originally isolated in 1998, stem cells are undifferentiated cells that can develop indefinitely into more specialized body cells, including neural, muscle, blood, and organ cells. These cells show promise in being able to regenerate human tissue of various kinds, with notable success in treating neurological diseases and conditions, such as Parkinson's disease and spinal cord damage.
The use of these stem cells is controversial because the best source for the cells is human fetal tissue from the earliest stages of embryonic development. Scientists typically use unwanted fertilized eggs from frozen in-vitro fertilization to harvest the stem cells, which form 4?5 days after fertilization. These embryos must be destroyed to harvest the cells, and those opposing the research consider this tantamount to the taking of human life.
In Aug. 2001, President Bush announced that he would permit federal funding of research on stem cells from human embryos, but only those cells that had already been extracted. This effort toward compromise seemed to satisfy neither side of the debate. Many scientists advocating stem-cell research responded that the number of existing lines of stem cells (according to the Bush administration about 60 lines exist) may not be enough to adequately complete research because existing cell lines can be easily contaminated or die out. Other advocates felt that limiting research would limit the potential of stem cells to cure diseases and help the millions living with Alzheimer's, diabetes, Parkinson's, and other medical conditions. Academic biologists were also concerned about whether the private companies and foundations holding the cell lines would be willing to allow their use in public research, and at what cost and with what restrictions. Meanwhile, those opposed to stem-cell research claimed that Bush had broken his promises not to federally fund research that destroyed human life.
Faster than a Speeding Bullet
In June 2001, Intel Corporation researchers, led by Dr. Robert Chau, announced that they had created the technology needed to produce the world's smallest and fastest silicon transistor on a mass scale. With these diminutive gatekeepers of electronic current, switching on and off 1.5 trillion times a second, microprocessors could complete a billion calculations in the time it takes a person to blink. And these transistors run at speeds of nearly 20 gigahertz?just a year ago the top speed of a transistor was one gigahertz, which was considered absolutely breathtaking.
These tiny transistors, elements of which are just 20 nanometers long (a nanometer is one-billionth of a meter, or about 1/50,000 of a human hair) and 80 atoms wide, are created using electron-beam lithography. In this process, a thin stream of electrons etches features onto a film-covered slice of silicon.
Currently, computer-chip producers use photolithography to shine ultraviolet light through a stencil punched with millions of miniscule patterns. The UV light that penetrates the stencil is then absorbed by tiny plastic-coated silicon slices. The finished product of photolithography is about 125 nanometers wide?a behemoth compared to the results of electron-beam lithography. Electron-beam lithography is part of nanotechnology, a new science that builds microscopic structures molecule by molecule. Intel Corporation plans to produce computers using the tiny transistors by 2007.
Plant biologists Eduardo Blumwald of the University of California at Davis and Hong-Xia Zhang of the University of Toronto have developed a tomato plant with a salt-tolerant gene. This new plant is important because it can grow successfully in soil irrigated, and often ruined, by salty water. Some 24.7 million acres of the planet's farmable land are poisoned every year by such irrigation when there is not enough seasonal rainfall to wash away the accumulation of salt?areas of the U.S., China, India, and Pakistan are significantly affected. Salty irrigation water spoils plants and leaves deposits of minerals that weaken future crops by damaging their ability to take in water through their roots. High salt concentrations in soil also draw water out of these crops, dehydrating and eventually killing the plants. Not only does the new tomato manage to grow in salt-affected areas, but it also promises to act as a sponge, soaking up the salinity in the soil and helping to restore it to an arable state.
An ongoing study of Canadian fathers-to-be at the Mayo Clinic revealed changes in the men's hormone levels as they approached fatherhood for the first time. The authors of the study, Sandra J. Berg and Katherine E. Wynne-Edwards of Queen's University in Kingston, Ont., tested saliva samples for levels of testosterone, cortisol, and estradiol. Results of the study show decreased levels of testosterone, the principal male hormone, and cortisol, a stress hormone, and increased levels of estradiol, a female hormone associated with maternal behavior. Wynne-Edwards speculates that the study points to evidence of ?subtle modulations that occur at this absolutely critically biological time in a man's life that make it?we would guess, and it is just a guess at this point?easier for him to make the transformation into committed fatherhood.?
A Body in Motion
Results published in the Aug. 2001 Journal of Experimental Psychology: Human Perception and Performance show that doing several tasks at once?multitasking?may diminish the productivity with which any of the tasks is performed. Researchers Joshua Rubenstein from the Federal Aviation Administration and David Meyer and Jeffrey Evans from the University of Michigan studied the performance of subjects as they switched between tasks including math problems and sorting geometrical objects.
The study's results support the idea that executive control is composed of two stages: goal shifting (?I choose to do X and not Y now?) and rule activation (?I am working according to the rules of X now and not the rules of Y?). Moving between these stages, people unconsciously evaluate the familiarity and complexity of tasks and then assign their cognitive resources to executing the task.
Rubenstein, Meyer, and Evans determined that switching tasks caused the subjects to lose time, and that time losses increased significantly as the tasks became more complex or unfamiliar. The study also showed that the phase of rule activation could take several tenths of a second, a considerable length of time if the person switched tasks often. Meyer offers the example of a driver using a cellular phone: a half second lost to task-switching can mean the difference between life and death, because during the time that the car is not totally under control, it can travel far enough to crash.
To Clone or Not to Clone
In March 2001, fertility doctors Severino Antinori of Italy and Panayiotis Zavos of the U.S. announced to a symposium of international fertility experts in Rome that they planned to begin reproducing human beings through cloning in Oct. 2001. The doctors stated that ?they were motivated solely by the desire to help infertile couples have children? and claimed that 200 couples are ready to have children through cloning. In response to this announcement, the Italian government threatened to revoke Antinori's medical license if he went through with these plans. In Aug. 2001, the U.S. House of Representatives voted to ban human cloning completely and threatened arrest and prison sentences for offenders.
Scientists opposed to human cloning have cited instances of early death, unpredictable genetic deformities, and genetically triggered diseases such as cancer in animal clones. Dr. Harry Griffin of the Scottish Roslin Institute, which produced the cloned sheep Dolly, said, ?Many of the animal clones die late in pregnancy or soon after birth and show developmental abnormalities?[T]he efficiency?in published work is very low?around 2% of the embryos that are created by cloning make it to term.?
Countering these concerns, Duke University Medical Center researchers have found that humans can be cloned with fewer complications than animals because of a gene protein known as insulin-like growth factor 2 receptor (IGF2R). This gene protein functions in the normal growth and development of the embryo, keeping in check any developmental abnormalities. In human sexual reproduction, an active copy of IGF2R is passed to the offspring from each parent. In animal sexual reproduction one copy of the gene is ?turned off,? increasing the chances of abnormal embryonic development.
You Gotta Have Heart!
On July 2, 2001, fifty-nine-year-old Robert Tools became the first person to be equipped with a self-contained artificial heart. Surgeons Laman Gray and Robert Dowling at Jewish Hospital in Louisville, Ky., replaced Tool's heart with a battery-powered mechanical version called AbioCor during a 10-hour operation. Earlier artificial hearts were bulky and had to be connected to an external power source, which meant that the recipient had wires and tubes sticking out of his chest. The titanium-and-plastic AbioCor is the size of a small grapefruit, weighs just 2 lbs, runs on a battery imbedded in the ribcage, and can be charged by an external battery pack. After nearly five months of living with the mechanical heart, Robert Tools died on Nov. 30, after a bout of severe abdominal bleeding that was unrelated to his heart surgery. As of Dec. 14, 2001, five more AbioCor implants had been performed on patients, two of whom died.
A Pill with a Purpose
Following lightning-fast FDA approval in May 2001, a new form of targeted cancer therapy known as Gleevec (formerly ST1-571) may become available by the end of 2001. During a three-year study, Gleevec was used successfully to treat chronic myelogenous leukemia (CML), an adult cancer of the white blood cells. Gleevec, which is taken in pill form, targets an abnormal cancer-causing protein called BCR-ABL. Doctors conducting Gleevec research at the Oregon Health Sciences University reported that during the study Gleevec brought white blood cell counts to normal levels in all but one of 85 subjects. In June 2001, it was reported that some of the subjects had become resistant to Gleevec; developing another drug to be used along with Gleevec may yield a solution.
Gleevec is currently being tested on other cancers that are motivated by proteins similar to BCR-ABL. Clinical trials have shown that it is useful in treating gastrointestinal stromal tumors (GIST), and research is underway to test Gleevec's effectiveness against glioblastoma (a deadly brain tumor) and forms of prostate cancer and lung cancer.