To better understand the distortions, researchers at the Georgia Institute of Technology developed the first device to directly measure complex ultrashort light pulses in space and time at and near the focus. Measuring the pulse at the focus is important because that's where the beam is most intense and where researchers typically utilize it. Knowing how the light is distorted allows researchers to correct for the aberrations by changing a lens or using a pulse shaper or compressor to manipulate the pulse into the desired form.

"Researchers have always measured the pulse immediately as it exited the laser, so they didn't realize the extent to which the pulse became distorted by the time it reached the focus after traveling through the optics and lenses in the system," said Rick Trebino, a professor in the Georgia Institute of Technology's School of Physics and Georgia Research Alliance Eminent Scholar in Ultrafast Optical Physics.

The device was described in a presentation at the Conference on Lasers and Electro-Optics on May 8. This research was funded by the National Science Foundation and published in the August 2007 issue of the journal Optics Express.

It is difficult to measure ultrashort pulses because they typically last between a few femtoseconds and a picosecond, which are 10-15 and 10-12 of a second, and faster than the response time of the fastest electronics.

"The light comes out as a train of extremely short bursts. The laser crams all of the energy of a continuous laser into a few femtoseconds, which creates really intense laser pulses," said Pam Bowlan, a graduate student supported by the Technological Innovation: Generating Economic Results (TI:GER) program.

To achieve the highest possible intensity of the laser, the pulse must be as small as possible in space and as short as possible in time. However, focused pulses nearly always have distortions in time that vary significantly from point to point in space due to lens aberrations in focusing optics.

To address those issues, the new device, called SEA TADPOLE (Spatial Encoded Arrangement for Temporal Analysis by Dispersing a Pair of Light E-fields), allows researchers to measure complicated ultrashort pulses simultaneously in space and time as they go through the focus.

"A lot of chemists and biologists use ultrafast lasers, so it was important that our device be easy to use because non-laser scientists don't want to spend all day measuring their laser pulses," noted Bowlan.

The research team - which also included former graduate students Pablo Gabolde and Selcuk Akturk - used the concept of interferometry to measure a pulse in space and time. Two pulses, one reference and one unknown, were sent through optical fibers. The fibers were mounted on a scanning stage so that the pulses could be measured at many locations around the focus.

The pulses were crossed and an interference pattern was recorded for each color of the pulse at each location with a digital camera. The patterns were used to determine the shape of the unknown pulse in space and time and to create movies showing how the intensity and color of the pulse changed in space and time as it focused.

"Because the laser pulses enter SEA TADPOLE through optical fibers, which only collect a very small portion of the light, the device naturally measures pulses with high spatial resolution and can measure them at a focus spot size smaller than a micron," explained Bowlan. To further improve the spatial resolution of the device, the research team began to use specialized fibers, called near-field scanning optical microscopy fibers, which can resolve features smaller than the wavelength of the light.

The researchers tested the device by measuring ultrashort pulses focused by various lenses, since each lens can cause different complex distortions. To validate the measurements, Bowlan performed simulations of pulses propagating through the experimental lenses. Results showed that a common plano-convex lens displayed chromatic and spherical aberrations, whereas more expensive aspheric and doublet lenses exhibited mostly chromatic aberrations.

Spherical aberrations occur when the light that strikes the edges of the lens gets focused to a different point than the light that strikes the center, creating a larger, inhomogeneous focused spot size. Chromatic aberrations occur because the many colors in the laser travel at different speeds and do not stay together in space and time as the pulse passes through glass components in the experimental setup, such as lenses. As a result, each color arrives at the focus at a different time, creating a rainbow of colors in the electric field images.

Aberrations can drastically increase the pulse length, which decreases the laser intensity. A lower intensity forces researchers to increase the power of the laser, increasing the possibility of damaging the sample. Aberrations can also yield odd pulse and beam shapes at the focus, which complicate the interpretation of the experiment or application.

"Our system tells researchers what types of aberrations are present in instrumentation, which then allows them to test different lenses in the instrumentation setup or use a pulse shaper to create the desired pulse at the focus that's free of distortions," added Bowlan.

What makes them do it?

A team of scientists led by Iain Couzin of Princeton University and including colleagues at the University of Oxford and the University of Sydney believes it may finally have an answer to this enduring mystery.

"Cannibalism," said Couzin, an assistant professor of ecology and evolutionary biology at Princeton.

Writing in the May 8 online edition of Current Biology, Couzin and colleagues say that the collective motion of locusts is driven by "cannibalistic interactions."

"Cannibalism is rife within marching bands of locusts," said Couzin. Desert locusts usually feed on vegetation, but individual locusts have been observed to feed on other live locusts or cadavers. This behavior and its effect upon the group, however, have not previously been studied.

"No one knew until now that cannibalistic interactions are directly responsible for the collective motion exhibited by these bands," added Couzin, whose graduate student, Sepideh Bazazi, is the lead author on the paper.

In zoology, cannibalism is defined as occurring when any species consumes members of its own kind.

Young locusts are pressed to eat others when the food supply necessary for supporting the population starts to dwindle. Starved for essential nutrients such as protein and salt, young locust "nymphs" will nip at each other. Those under siege react by running from the aggressors. Others get jittery and simply seek to put space between them and any locust approaching from behind. That's how one aggressive interaction can lead to another and collectively start a vast migration, Couzin said.

And the activity intensifies, as the biting and ominous approach of others increases both the propensity to move and the forward momentum of individual locusts.

The researchers reached their conclusion by studying immature, flightless locusts. They developed computerized motion analysis to automatically track the insects marching in an enclosed arena.

In nature, Couzin said, these locust nymphs can gather in large mobile groups called bands. They can stretch over tens of miles, devouring vegetation as they march. They inevitably precede the flying swarms of adult locusts.

"Once they take flight, locust control is extremely expensive and ineffective," Couzin said. "So understanding when, where and why the bands of juvenile locusts form is crucial for controlling locust populations."

Through history, locusts have invaded up to one-fifth of the Earth's surface, he said. They have contributed to major humanitarian crises in areas such as Darfur and Niger.

Besides having practical applications, understanding the movement of locusts also is part of a growing inquiry by scientists into an area known as group dynamics. With locusts, researchers have been seeking to understand how the group seems to move with the synchronized perfection of the Rockettes when there is no centralized leader and individuals can barely see beyond a few neighbors on either side.

Animal groups such as flocks of birds, schools of fish and swarms of insects frequently exhibit such complex and coordinated collective motion and present a great opportunity to understand how local interactions can lead to vast collective behavior, the scientists said.

"Meiotic silencing also occurs in worms, mice and human beings," said Patrick Shiu, assistant professor of biological sciences in the MU College of Arts and Science. "It's unlikely that all share the same mechanism, but the principle of targeting unpaired DNA for silencing seems to be found in both simple and complex organisms. Knowing the process of how DNA in molds is targeted for silencing could be important for silencing genes you don't want to be expressed, like disease-causing genes."

Shiu and his colleagues discovered that each sexual cell in mold has an internal mechanism that "scans" paired chromosomes for anomalies. The researchers found that when one chromosome in a pair carries an extra copy of a gene not found in its partner chromosome, it is a good indication of an intruder and the fungus will "turn off" all copies of that gene during meiosis. The researchers call this process "meiotic silencing by unpaired DNA," or MSUD.

"MSUD defends the fungus against invasion at a time when chromosomes are especially vulnerable to the spread of viruses and insertion sequences," Shiu said.

Shiu's research enhances understanding of how to "shut off" undesirable genes, sheds light on the genetic components of the MSUD pathway, and may have applications in a number of industries, including pharmaceuticals and agriculture.

Because of his contribution to the field of genetics, Shiu recently received the Beadle and Tatum Award, named after Nobel Prize-winning geneticists George Beadle and Edward Tatum. The award was established to recognize outstanding and original research by a scientist using Neurospora, a type of bread mold, as a model organism.

The dime-sized laser, to be described Thursday, May 8, at the Conference on Lasers and Electro-Optics,* emits 10 billion pulses per second, each lasting about 40 femtoseconds (quadrillionths of a second), with an average power of 650 milliwatts. For comparison, the new laser produces pulses 10 times more often than a standard NIST frequency comb while producing much shorter pulses than other lasers operating at comparable speeds. The new laser is also 100 to 1000 times more powerful than typical high-speed lasers, producing clearer signals in experiments. The laser was built by Albrecht Bartels at the Center for Applied Photonics of the University of Konstanz.

Among its applications, the new laser can be used in searches for planets orbiting distant stars. Astronomers look for slight variations in the colors of starlight over time as clues to the presence of a planet orbiting the star. The variations are due to the small wobbles induced in the star's motion as the orbiting planet tugs it back and forth, producing minute shifts in the apparent color (frequency) of the starlight. Currently, astronomers' instruments are calibrated with frequency standards that are limited in spectral coverage and stability. Frequency combs could be more accurate calibration tools, helping to pinpoint even smaller variations in starlight caused by tiny Earthlike planets. Such small planets would cause color shifts equivalent to a star wobble of just a few centimeters per second. Current instruments can detect, at best, a wobble of about 1 meter per second.

Standard frequency combs have "teeth" that are too finely spaced for astronomical instruments to read. The faster laser is one approach to solving this problem. In a separate paper,** the NIST group and astronomer Steve Osterman at the University of Colorado at Boulder describe how, by bouncing the light between sets of mirrors a particular distance apart, they can eliminate periodic blocks of teeth to create a gap-toothed comb. This leaves only every 10th or 20th tooth, making an ideal ruler for astronomy.

Both approaches have advantages for astronomical planet finding and related applications. The dime-sized laser is very simple in construction and produces powerful and extremely well-defined comb teeth. On the other hand, the filtering approach can cover a broader range of wavelengths. Four or five filtering cavities in parallel would provide a high-precision comb of about 25,000 evenly spaced teeth that spans the visible to near-infrared wavelengths (400 to 1100 nanometers), NIST physicist Scott Diddams says.

Osterman says he is pursuing the possibility of testing such a frequency comb at a ground-based telescope or launching a comb on a satellite or other space mission. Other possible applications of the new laser include remote sensing of gases for medical or atmospheric studies, and on-the-fly precision control of high-speed optical communications to provide greater versatility in data and time transmissions. The application of frequency combs to planet searches is of international interest and involves a number of major institutions such as the Max-Planck Institute for Quantum Optics and Harvard Smithsonian Center for Astrophysics.

The movement of this iron snow could be responsible for Mercury's mysterious magnetic field, say researchers from the University of Illinois and Case Western Reserve University. In a paper published in the April issue of the journal Geophysical Research Letters, the scientists describe laboratory measurements and models that mimic conditions believed to exist within Mercury's core.

"Mercury's snowing core opens up new scenarios where convection may originate and generate global magnetic fields," said U. of I. geology professor Jie (Jackie) Li. "Our findings have direct implications for understanding the nature and evolution of Mercury's core, and those of other planets and moons."

Mercury is the innermost planet in our solar system and, other than Earth, the only terrestrial planet that possesses a global magnetic field. Discovered in the 1970s by NASA's Mariner 10 spacecraft, Mercury's magnetic field is about 100 times weaker than Earth's. Most models cannot account for such a weak magnetic field.

Made mostly of iron, Mercury's core is also thought to contain sulfur, which lowers the melting point of iron and plays an important role in producing the planet's magnetic field.

"Recent Earth-based radar measurements of Mercury's rotation revealed a slight rocking motion that implied the planet's core is at least partially molten," said Illinois graduate student Bin Chen, the paper's lead author. "But, in the absence of seismological data from the planet, we know very little about its core."

To better understand the physical state of Mercury's core, the researchers used a multi-anvil apparatus to study the melting behavior of an iron-sulfur mixture at high pressures and high temperatures.

In each experiment, an iron-sulfur sample was compressed to a specific pressure and heated to a specific temperature. The sample was then quenched, cut in two, and analyzed with a scanning electron microscope and an electron probe microanalyzer.

"Rapid quenching preserves the sample's texture, which reveals the separation of the solid and liquid phases, and the sulfur content in each phase," Chen said. "Based on our experimental results, we can infer what is going on in Mercury's core."

As the molten, iron-sulfur mixture in the outer core slowly cools, iron atoms condense into cubic "flakes" that fall toward the planet's center, Chen said. As the iron snow sinks and the lighter, sulfur-rich liquid rises, convection currents are created that power the dynamo and produce the planet's weak magnetic field.

Mercury's core is most likely precipitating iron snow in two distinct zones, the researchers report. This double-snow state may be unique among the terrestrial planets and terrestrial-like moons in our solar system.

"Our findings provide a new context into which forthcoming observational data from NASA's MESSENGER spacecraft can be placed," Li said. "We can now connect the physical state of our innermost planet with the formation and evolution of terrestrial planets in general."

In response to the need for safe and effective alternatives to methyl bromide, researchers at the Instituto Tecnologico Agrario de Castilla y Leon in Valladolid, Spain, undertook a 3-year project to study new methods of weed control in strawberry nurseries. Results of the comprehensive research project were published in the February 2008 issue of HortScience.

According to lead researcher Eva García-Méndez, "the phaseout of methyl bromide requires effective alternatives for soil disinfestation, particularly in high-elevation strawberry nurseries." In the study, MB alternatives were evaluated for weed control and plant yields at strawberry nurseries participating in Spain's Methyl Bromide Alternatives Project (INIA). Two types of field trials were carried out: replicated experiments and commercial-scale field demonstrations.

In the replicated experiments eight fumigant treatments were evaluated each year, including the nonfumigated control and commercial standard methyl bromide plus chloropicrin mixture. Other treatments evaluated included: dazomet, chloropicrin alone, metam sodium plus chloropicrin, chloropropene:chloropicrin, DMDS plus chloropicrin, and propylene oxide. The best alternative treatments from the replicated experiments were then tested in the demonstration phase of the project.

The researchers discovered that several of the chemical alternatives they evaluated controlled weeds as consistently as MB, but all of the alternatives studied were less consistent than MB in terms of plant yields. They also found that the use of some types of barrier films increased the performance and consistency of alternative pesticides and that environmental factors such as weather, soils, and rotational crops contributed to inconsistencies in weed control and runner yields at high-elevation nurseries.

In summary, García-Méndez stated: "Replacements for methyl bromide will require more than one fumigant component as well as a higher level of management of pest populations in the fields during rotational crop production. It is necessary to continue evaluation of alternative fumigants for strawberry nurseries to focus on commercial field-scale demonstrations. Moreover, European Union regulatory restrictions may require the use of non-chemical alternatives in the near future. The need for evaluations of chemical and non-chemical soil disinfestation methods is urgent."

New research shows that birds babbling involves its own specialized brain circuitry, separate from that used for adult singing. This finding underscores the importance of the exploratory behaviors -- such as infant stepping, hand motions, vocalizations and play -- that help young animals learn how to use their bodies and make sense of the world.

Phoenix Mars Lander on course for May 25 touchdown.

NASA today announced an opportunity for anyone to submit their name to be included on a DVD and rocketed into space as part of NASA's Kepler Mission, scheduled to launch in February 2009 from NASA's Kennedy Space Center, Fla.

"This mission will provide our first knowledge of Earth-like planets beyond our solar system," said Kepler Mission principal investigator William Borucki.

The Name in Space DVD will be mounted on the exterior of the spacecraft in November 2008. A video of the DVD being mounted on the spacecraft will be taken and posted on the Kepler Mission Website prior to the spacecraft being shipped to NASA's Kennedy Space Center in December of this year. A copy of the DVD with all of the names and messages will be given to the Smithsonian Institution's National Air and Space Museum, Washington.

"It's a way for the public to participate in our space program,"explained David Koch, deputy principal investigator for the Kepler Mission. According to Koch, there's no limit to the number of names that can be submitted for inclusion on the DVD.

"We're looking for several million names," Koch said. "The only limitation is people's interest."

Anyone who wants to participate in the Name in Space project should submit their name, the state or country they live in and if they desire, a short statement (500 words or less) answering the question: "Why do you think the Kepler Mission is important?" The deadline for submissions to the Kepler Mission Web site is Nov. 1, 2008.

Certificates of Participation will be available for printing from the Kepler Mission Web site. The certificate states that the person whose name has been submitted has been included on the list of names launched in 2009 with the Kepler spacecraft into orbit around the sun. There is no charge for participating in the project or for printing the certificate.

Name in Space is an international activity associated with the International Year of Astronomy 2009 in recognition of the 400th anniversary of Johannes Kepler's publication of his first two laws of planetary motion.

Kepler is a NASA Discovery mission. NASA Ames is the home organization of the science principal investigator and is responsible for the ground system development, mission operations and science data analysis. Kepler Mission development is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Ball Aerospace & Technologies Corp., Boulder, Colo., is responsible for developing the Kepler flight system.

To submit names and learn more about the Kepler Mission, visit:

http://kepler.nasa.gov/

Alexandre Wathaut, Provincial Director for ICCN in North Kivu said: "This is the worst month we have seen in a long time in terms of recorded elephant deaths. ICCN is making official representations to the Congolese military and to the militia for this slaughter to stop. We call on the international community to engage in solving the region's political problems, for the sake of the local population as well as for Virunga's unique wildlife."

South Africa's 13-year moratorium on elephant culling was lifted today, raising concerns of a return to the international trade in ivory seen in the 1970s and 1980s. The growing presence of China in the region has also increased the local demand for ivory. According to a BBC report earlier this week, Indian MONUC troops flew a helicopter into Virunga National Park to trade ammunition for ivory with the FDLR. The concern is that this news is filtering through to the well-armed groups in the area who now see an opportunity to raise funds by killing elephants for ivory.

Dr Emmanuel de Merode, Director of WildlifeDirect.org, said: "The upsurge in elephant killings in Virunga is part of a widespread slaughter across the Congo Basin, and is being driven by developments on the international scene: the liberalisation of the ivory trade, being pushed by South Africa, and the increased presence of Chinese operators on the ground, who feed a massive domestic demand for ivory in their home country."

There were 3500 elephants in Virunga National Park in 1959. Surveys in 2006 estimated that there were only 350 elephants left, and the number is believed to have dropped further since. The death of 14 elephants therefore has a considerable impact on the viability of the local elephant population.

The Cerrado's wooded grassland once covered an area half the size of Europe , but is now being converted to cropland and ranchland at twice the rate of the neighboring Amazon rainforest, resulting in the loss of native vegetation and unique species.

An expedition comprising scientists from Conservation International (CI) and several Brazilian universities found 14 species believed new to science - eight fish, three reptiles, one amphibian, one mammal, and one bird - in and around the Serra Geral do Tocantins Ecological Station, a 716,000-hectare (1,769,274-acre) protected area that is the Cerrado's second largest.

The lizard, of the Bachia genus, resembles a snake due to its lack of legs and pointed snout, which help it move across the predominantly sandy soil formed by the natural erosion of the escar pm ents of the Serra Geral. Other suspected new species include a dwarf woodpecker (genus Picumnus) and horned toad (genus Proceratophrys).

"It's very exciting to find new species and data on the richness, abundance, and distribution of wildlife in one of the most extensive, complex, and unknown regions of the Cerrado," said CI biologist Cristiano Nogueira, the expedition leader. "Protected areas such as the Ecological Station are home to some of the last remaining healthy ecosystems in a region increasingly threatened by urban growth and mechanized agriculture."

The team also recorded several threatened species such as the hyacinth macaw, marsh deer, three-banded armadillo (tatu-bola), the Brazilian merganser, and the dwarf tinamou among more than 440 species of vertebrates documented during the 29-day field expedition.

Comprising 21 percent of Brazil , the Cerrado is the most extensive woodland-savanna in South America . Large mammals such as the giant anteater, giant armadillo, jaguar and maned wolf struggle to survive in the fast-changing habitat also know as Brazil 's breadbasket.

The expedition included 26 researchers from the University of São Paulo and its Museum of Zoology ; the federal universities of São Carlos and Tocantins ; and CI-Brazil. It was funded by the O Boticário Foundation for Conservation of Nature, with the support of the NGO Pequi-Pesquisa e Conservação do Cerrado (Research & Conservation of the Cerrado).

"The geographic distribution of some of the species registered is restricted to the area of the ecological station; thus their survival depends on the good management of the protected area and its immediate surroundings," said Luís Fabio Silveira, of the Department of Zoology of the University of São Paulo . "From the survey we can obtain data concerning the anatomy, reproductive biology, life cycle, and distribution of the species, all of which help us in future conservation programs."

Final results of the study, including the formal description of new species, will be used to support the develo pm ent of a management plan for the Ecological Station, which was created in 2001.

"We need to know our protected areas better, especially the ecological stations whose principal objective is to generate scientific knowledge of Brazilian biodiversity, so little studied and already so severely threatened," Nogueira said. "Unfortunately, extensive areas of the Cerrado, like the Ecological Station, are becoming increasingly rare, thus making the data collected even more important. Above all, it is necessary to know to conserve."

Photos are available at the following link:
http://images.conservation.org/admin/packaging/viewtransmit_ext.aspx?messageId=102362&userName=sbruce&session=1969ac292ab5d15ee5b212802cbc9c19

The researchers found evidence that fungi can "lock" depleted uranium into a mineral form that may be less likely to find its way into plants, animals, or the water supply.

"This work provides yet another example of the incredible properties of microorganisms in effecting transformations of metals and minerals in the natural environment," said Geoffrey Gadd of the University of Dundee in Scotland. "Because fungi are perfectly suited as biogeochemical agents, often dominate the biota in polluted soils, and play a major role in the establishment and survival of plants through their association with roots, fungal-based approaches should not be neglected in remediation attempts for metal-polluted soils."

The testing of depleted-uranium ammunition and its recent use in Iraq and the Balkans has led to contamination of the environment with the unstable metal, Gadd explained. Depleted uranium differs from natural uranium in the balance of isotopes it contains. It is the byproduct of uranium enrichment for use in nuclear reactors or nuclear weapons and is valued for its very high density. Although less radioactive than natural uranium, depleted uranium is just as toxic and poses a threat to people.

In the new study, the researchers found that free-living and plant symbiotic (mycorrhizal) fungi can colonize depleted-uranium surfaces and transform the metal into uranyl phosphate minerals.

While they probably still pose some threat, he said, "The fungal-produced minerals are capable of long-term uranium retention, so this may help prevent uptake of uranium by plants, animals, and microbes. It might also prevent the spent uranium from leaching out from the soil."

Gadd said that a combination of environmental and biological factors is involved in the process. First, the unstable uranium metal gets coated with a layer of oxides. Moisture in the environment also "corrodes" the depleted uranium, encouraging fungal colonization and growth. While the fungi grow, they produce acidic substances, which corrode the depleted uranium even further. Some of the substances produced include organic acids that convert the uranium into a form that the fungi can take up or that can interact with other compounds. Ultimately, he said, the interaction of soluble forms of uranium with phosphate leads to the formation of the new uranium minerals that get deposited around the fungal biomass.

"We have shown for the first time that fungi can transform metallic uranium into minerals, which are capable of long-term uranium retention," the researchers concluded. "This phenomenon could be relevant to the future development of various remediation and revegetation techniques for uranium-polluted soils."

"Our results for 25 years of research show problems with lack of iron. For us to find this result is a big deal, it's really unexpected," said Dr. Betsy Lozoff, University of Michigan research professor at the Center for Human Growth and Development, and the study's principal investigator.

U.S. infant formulas typically come fortified with 12 mg/L of iron to prevent iron-deficiency anemia. Europe generally uses a lower amount. In infants, iron-deficiency anemia is associated with poorer development, and during pregnancy it contributes to anemia in mothers, contributing to premature birth, low birth weight and other complications.

"I thought that behavior and development would be better with the 12 mg formula," said Lozoff, also professor of pediatrics in the U-M Department of Pediatrics and Communicable Diseases at the Medical School and C.S. Mott Children's Hospital

The U-M study of 494 Chilean children showed that those who received iron fortified formula in infancy at the 12 mg used in the U.S. lagged behind those who received low-iron formula in cognitive and visual-motor development by age 10 years. Lozoff stressed that most children who received the 12 mg formula did not show lower scores. But the 5 percent of the sample with the highest hemoglobin levels at 6 months showed the poorest outcome. Your body needs iron to make hemoglobin, a substance in red blood cells that enables them to carry oxygen. High hemoglobin generally indicates sufficient iron.

Adversely affected children scored 11 points lower in IQ and 12 points lower in visual-motor integration, on average; the average overall score on both tests was 100. A similar pattern was observed for spatial memory and other visual-motor measures.

Lozoff noted that not many infants in Chile had high hemoglobin levels at the time since there was no iron-fortification program for infants and that more than 5 percent of U.S. infants might have high hemoglobin levels in early infancy.

In this randomized study, healthy infants without iron-deficiency anemia were given formula with either 12 mg or 2.3 mg iron from 6 to 12 months and followed to 10 years. The next step is to test the participants again at age 16, Lozoff said, who says that no such study has been conducted in the United States or elsewhere.

Iron deficiency occurs because babies grow so quickly they often "grow out" of the amount of iron they are born with. Breast milk is thought to contain the iron a baby needs for 4-6 months, Lozoff said. Other important sources of iron for infants include iron-fortified infant formulas and cereals, iron drops and meat.

Infants are typically not tested for hemoglobin or iron levels before 9-12 months. It would be premature to recommend earlier testing or to avoid supplemental iron based on the study's results, Lozoff said. She expects parents to be concerned, but stressed that results must be reproduced in other studies.

"At this point there's no basis for changing practice, but it's really important that we have continued research on this issue," she said.

The research team studied the bone mass and analysed the genetics of a man with enviable health who at the time of the study was 113 years old. The research was carried out with four other members of his family: a 101-year-old brother, two daughters aged 81 and 77, and a nephew aged 85, all of them born and still living in a small town of the island of Menorca. The research findings were recently published in the Journal of Gerontology and reported that the man's bones were in excellent conditions: his bone mass was normal, there were no anomalous curvatures and he had never sustained a fracture.

With regard to the genetical analyses, researchers were unsuccessful in finding any mutations in the KLOTHO gene, which is generally related to a good level of mineral density and therefore healthy bones. Neither did they find any mutations in the LRP5 gene, which is associated with longevity. None of the members of the family who participated in the study presented any mutations in this gene.

The results of the research do not rule out the possibility that other genetic mutations could positively influence longevity. However, researchers do point out the fact that the excellent health of this family, and of the 113-year-old man in particular, is probably due to a Mediterranean diet, the temperate climate of the island, a lack of stress and regular physical activity. The article underlines the fact that until the age of 102, the man cycled every day and looked after the family orchard.

Researchers are compiling information on the status of Africa's natural resources using satellite data.