Findings

Smoking may blow away blues

Tobacco smoke may act on the brain like an antidepressant drug, scientists have found.

The results of a three-year study may provide another clue as to why kicking the habit may be so difficult and why there is a particularly high rate of smoking among people with depression.

A team led by Gregory Ordway and Violetta Klimek at the University of Mississippi Medical Center in the United States found that the brains of chronic smokers undergo biological changes similar to those caused by antidepressant drugs. The research has been published in the Archives of General Psychiatry .

"What our study demonstrates for the first time is that chronic smoking produces biological changes in the human brain that are antidepressant-like," Ordway said.

The investigators said the biological changes are probably not caused by nicotine. Instead, it appears that a compound produced when tobacco burns is responsible.

The study involved 20 human cadaver brains - ten from smokers and ten from non-smokers.

Ordway examined a lower, posterior portion of the brain called the locus coeruleus that is associated with depression.

In the chronic smokers, the locus coeruleus had neurochemical abnormalities of a sort usually linked to the use of antidepressants.

Nicotine does have antidepressant qualities but does not act in a way that would have this effect.

Ordway said the study was uncertain whether chronic smokers had these brain characteristics before they started smoking, which could increase their susceptibility to becoming addicted.

Instead, he suspected that the smoking itself caused the neurochemical changes. The scientists are now investigating the link.

Medievals were night creatures

For the more superstitious medieval peasant, the night was a time to shelter inside from the evil spirits and demons that stalked the countryside. However, historians have found that for many others the darkness spelled freedom.

Deborah Youngs, lecturer in medieval history at the University of Wales, Swansea, and Simon Harris, at Durham University, are shining light on the hidden night culture of the Middle Ages and the efforts of the authorities to stamp it out.

Their preliminary results, based on an examination of court and coroners records, constitute a chapter in the forthcoming book The Monstrous Middle Ages .

They overturn old assumptions that medieval people were frightened of the night to the extent that few dared venture out of doors.

"We're slowly building a picture to show nobody, not even children, was excluded from this night-time culture, except those women who valued their reputations," Youngs said. "We're reclaiming the night for the medieval period."

There were obvious difficulties in being active at night. This was a time without street lighting and when candles were expensive.

Nevertheless, many people took part in feasts and celebrations that went on by firelight.

For most apprentices and servants, such nocturnal revelry was a much more frequent pursuit. This was the one time they could get away from their highly regulated and restricted working lives.

Court records reveal that late-night drinking sessions for these adolescent men often ended in brawls outside taverns.

While the historians have found no evidence that crime was particularly more prevalent after sunset, it seems the courts cracked down heavily on crimes committed in darkness. Such offences - burglaries, muggings and murders - appear to have been more premeditated.

Other people had to work at night, such as glassworkers and grave diggers.

Church and town authorities tried to control this activity as much as possible. For example, regulations in Northampton forbade butchers working before daylight, while metalworkers in London were required to stop by 9pm.

In one case in 1321, 47 London traders were charged after being caught selling their wares after vespers.

Churchmen weighed in by stressing the association of darkness with evil, sin and the devil. The church, in contrast, was a beacon of light.

Indeed, there were genuine dangers in the dark. Coroners' records note the deaths of people falling down stairs or into ditches.

Even an archbishop of Canterbury was not above the perils of darkness. St Anselm was apparently answering the call of nature in the middle of the night when he tumbled through a broken cistern lid and drowned.

Star trail backs up the theories

The cosmic equivalent of a "jet contrail" discovered by astronomers could mark the passage of a dwarf star hurtling through interstellar space.

The straight filament of ionized gas stretches 2.5 degrees across the sky near the Plough.

Such trails have been predicted by theoreticians but their faintness has kept them from view until now.

The discovery was made by Peter McCullough at the University of Illinois at Urbana-Champaign, and Robert Benjamin at the University of Wisconsin at Madison, in the United States. Their results are published in The Astronomical Journal .

"We believe the gas trail was produced by the radiation from a white dwarf or some other low-luminosity source zipping through the local interstellar medium and leaving behind an ionised wake," McCullough said.

"The problem is that we have not yet identified the source."

Benjamin said: "This could be the brightest trail visible from Earth and therefore the first one found."

Other possibilities include a jet of low-density stellar radiation or a linear wisp of gas from some nearby nebula.

The filament is roughly Y-shaped and is suspected to be 300 light-years from Earth - within our Milky Way galaxy - due to its large angular size in the sky.

It has been photographed by the University of Illinois's 40-inch reflecting telescope at the Mount Laguna Observatory in southern California.

The scientists are now hunting for the object that may have left the trail.