The Chandra image of the quasar GB1508+5714...  Full image

The cosmic microwave background radiation (CMBR) is the remnant light that was generated when the first atoms formed in the cosmos -- about 300,000 years after the Big Bang that created the universe.  The CMBR was discovered by SAO astronomer Bob Wilson and his colleague Arno Penzias while they were at Bell Labs in 1964, for which achievement they received the Nobel Prize in Physics in 1978.  Since then many experiments have confirmed and extended their amazing results. Although this radio radiation is ubiquitous and abundant, it is not all that easy to measure because it is almost perfectly uniform across the sky.  Astronomers continue to try to probe its secrets, though, because extremely tiny variations can reveal dramatic details of those formative epochs.

A team of SAO astronomers, Aneta Siemiginowska, Randall Smith, Tom Aldcroft, and Daniel Schwartz, along with two colleagues, have just reported their Chandra X-ray Observatory measurements of a distant quasar that - for the first time - sheds light on the properties of the CMBR as it existed after evolving (along with the rest of the universe) for about 1.3 billion years.  Writing in last week's Astrophysical Journal Letters, the SAO scientists report discovering an X-ray jet protruding from this very distant quasar; light left the object when the universe was this age -- or about ten times younger than it is now (about 13 billion years old).

The SAO astronomers argue that the X-ray jet was produced when very energetic particles, perhaps ejected from a massive black hole at the nucleus of this bright quasar, collided with the CMBR that permeated the universe then, as it does now.  They point out that the universe, which is expanding, was much smaller back then than it is currently. As a result all of the CMBR light, which was confined to this smaller universe, played a relatively more important role, and was able to interact with the ejected particles to produce these jets.  Similar jets may exist around other very distant objects, waiting to be discovered. The team concludes that their measurement is in agreement with current models of the expanding universe, and the Big Bang scenario for creation. If the team's result is confirmed, and if their interpretation is corroborated, the discovery means that X-rays may offer one of the best ways to study the CMBR as it was in the early days of the cosmos.

Leaf-cutter ants.  Full image

Leaf-cutter ants (Atta colombica) use trail following-a combination of pheromone and visual cues-to travel between their foraging sites and home nests. They also most likely use a directional reference system, such as a compass, not only when foraging, but also when forming new colonies, when foraging trails degrade, or when ants become displaced. One candidate directional reference system is the magnetic polarity compass.

Smithsonian Tropical Research Institute fellowship scientist Alexander Banks and colleagues tested the orientation of leaf-cutter ants under a magnetic field of reversed polarity, with the prediction that the ants would show 180 degrees deflection  compared with control ants in an unchanged geomagnetic field. When the sun's disc was unobstructed by clouds, the reversed-polarity ants' orientation was the same as that of control ants, implying that they did not use magnetic cues to orient themselves. However, when the sky was overcast, the reversed-polarity ants significantly shifted their mean orientation in comparison with both the control ants and the reversed-polarity ants under full sun. Although the ants did not totally reverse their direction, the results suggest a role for magnetic cues as they wind their way home after a hard day's work.

The north wall of the Grand Salon of the Renwick...  Full image

For decades, museums have attempted to hold their environments as close as possible to a temperature of 70±2°F and a relative humidity of 50±5%. They have assumed that a stable environment, ideally with no change whatever in temperature or relative humidity, would best preserve museum collections. This assumption remained untested until Marion Mecklenburg and Charles Tumosa of the Smithsonian Center for Materials Research and Education measured the response of many different museum materials to broader ranges of both temperature and relative humidity.

Their research showed that the recommended environmental limits were unnecessarily stringent, and in some cases were actually damaging museum property. For example, by maintaining these levels of relative humidity in winter, condensation and mold had so damaged the interior walls of the Renwick Gallery as to require extensive, repeated repairs. Other museums in the United States and Canada have also experienced the same sort of damage.

Mecklenburg and Tumosa proposed limits that are easier to meet: maintaining temperatures at 70±4°F and relative humidity at 45±8%. The lower relative humidity is expected to prevent condensation and the consequent building damage. More relaxed environmental limits can also reduce initial construction and subsequent operation costs by allowing for a smaller heating and air conditioning plant. The Smithsonian's Office of Facilities Engineering and Operations has adopted these guidelines.

American Airlines Fokker F100 suffered...  Full image

Every year, collisions between birds and aircraft (birdstrikes) cause millions of dollars in damage to commercial and military aircraft. From 1990 to 2002, the Federal Aviation Administration (FAA) estimated that wildlife strikes alone cost more than $345 million a year in damages and over 537,000 hours of aircraft downtime. Already in 2003, birdstrikes have cost the U.S. Air Force more than $44 million in the loss of three aircraft.

The National Museum of Natural History's (NMNH's) Feather Identification Laboratory is collaborating with the Air Force and the FAA to identify the species of birds involved in birdstrikes, which will enable habitat managers to design schemes that discourage birds' use of airfields, and will help aircraft manufacturers design aircraft that can withstand the impact of bird collisions.

Positive identification of species of birds is possible by studying the fragmentary feathers that are recovered from these strikes and comparing the samples to the vast museum collections of bird study skins and reference microslides stored in NMNH's Division of Birds. The identification of bird species by use of micro- and macroscopic feather characters, together with circumstantial evidence (e.g., locality, date, time of day) pertaining to the unknown sample, has led to the field of forensic ornithology, which was pioneered at NMNH by Smithsonian Associate Roxie Laybourne. This method couples traditional systematic ornithology with modern forensic techniques of microscopy, trace evidence, and circumstantial data to positively identify birds from unknown feather samples.

The Feather Lab, now fully funded through interagency agreements between the U.S. Air Force, the FAA, and the Smithsonian, supports three research positions. In 2003, The Smithsonian signed an agreement with the FAA to enhance the identification techniques by using DNA technology. Research is underway to sequence portions of four mitochondrial genes for 300 species of birds that are commonly involved in birdstrikes. This technology will greatly improve traditional methods of identification in cases that only have blood or tissue smears.

Litterbag with R. mangle leaves...  Full image

Because plant characteristics, such as litter quality, determine rates of decomposition, increased nutrient availability is expected increase both the decomposability of mangrove tissue and nutrient cycling. Candy Feller and Anne Chamberlain from Smithsonian Environmental Research Center measured the effects of nitrogen and phosphorus enrichment on leaf litter and belowground decomposition rates in three zones in an abandoned mosquito impoundment in Florida's Indian River County. A previous fertilization experiment showed that mangrove growth at this site is nitrogen-limited from the shoreline to the upland ecotone. Nutrient enrichment altered leaf-litter quality, thereby linking it to decomposition and belowground processes.

The researchers used litterbag experiments to quantify the effects of leaf-litter quality and soil nutrients, and their interactive effects on rates of mass loss and changes in litter nutrient concentrations over a year. They used standardized cotton strips to measure belowground decomposition over a three-week period. Their results show that while both the nutrient treatment and the zone had significant effects on litter decomposition rates and nutrient concentrations, only the zone (not nutrient enrichment) had a significant effect on belowground decomposition. Decomposition and nutrient mineralization are major pathways for energy and nutrient flow in mangrove and other ecosystems.  Litter studies such as the one performed in the mangroves at Fort Pierce further our understanding of how coastal eutrophication affects rates of nutrients recycling.

Stanley Heckadon, Director of STRI’s Office of...  Full image

In October, students from U.S. schools and Panama's Balboa Academy sent more than 1,100 questions to JASON  headquarters in Boston. Smithsonian Tropical Research Institute (STRI) scientist Stanley Heckadon, director of STRI's Office of Communications and Public Programs in Panama, participated in a 90-minute e-mail chat with these students. According to JASON coordinators, the chat beat all their previous participation records.

The students were interested in learning everything about STRI; about Panama's people, culture, and languages; and, of course, about the Panama Canal. Heckadon focused his responses on Panama's biodiversity, described Panama's different cultures and its citizens' respect of and pride in their diversity, and explained how building the Panama Canal opened the door to a revolution in tropical medicine.

"People living in the forest are poor only in a material sense," Heckadon said. "A young Embera boy learns very quickly while in elementary school how to build a house, a dugout canoe, and a paddle. And young girls learn how to make intricate baskets from forest products, like palms. In this sense, these young people are more mature than their peers in urban areas."

Upcoming chats include Arturo Lindsay, Roland Kays, Randy Morgan, Elisabeth Kalko, Jackie Willis, Roland Smith, Meg Lowman, Mark Wishnie, Mike Kaspari and Robert Stallard, president of the JASON Project. This week, Panama's Ministry of Education formally accepted the JASON study guide as part of the national curriculum.

Banks, A.; Srygley, R. 2003. "Orientation by Magnetic Field in Leaf-Cutter Ants, Atta Colombica,"  Ethology, 109:835-846.

Ferrer, A.; Gilbert, G. 2003. "Effect of Tree Host Species on Fungal Community Composition in a Tropical Rain Forest in Panama,"  Diversity and Distribution, 9:455-468.

Siemiginowska, A.; Smith, R.; Aldcroft, T.; Schwartz, D.; Paerels, F.; Petric, A. 2003. "An X-Ray Jet Discovered by Chandra in the z=4.3 Radio Selected Quasar GB1508+5714," Astrophysical Journal Letters, 598, L15.

Swanson, W.F; Johnson, W.E.; Cambre, R.C.; Citino, S.B.; Quigley, K.B.; Brousset, D.M.; Morais, R.N.; Moreira, N.; O'Brien, S.J.; Wildt, D. 2003. "Reproductive Status of Endemic Felid Species in Latin American Zoos and Implications for Ex Situ Conservation," Zoo Biology, 22:421-441.