Humans are not the only ones that like gold. Australian scientists have discovered a new fungus(真菌)that decorates its long,thread-like tendrils(卷须)with gold collected from the soil. The experts desperately hope the “gold digger” will provide information on the locations of gold deposits(沉淀物)and make searching for the precious meal easier, and more environmentally friendly.

The gold-loving fungus was discovered accidentally by a team of researchers led by Dr. Tsing Bohu, a scientist at Australia national science agency, CSIRO, when they were examining the microbes(微生物) in the soil at Boddington,a tiny town home to Australia’s largest gold mine.

A closer analysis suggested that the fungus uses chemical interactions with underground minerals to accumulate gold from its surroundings. Though fungi often interact with other things in nature, the reaction with gold was unexpected. “Fungi are well-known for playing an important role in the recycling of organic material, such as leaves and bark, as well as for the cycling of other metals,” Dr. Bohu explained. “But gold is so chemically inactive that this interaction is both unusual and surprising.”

The fungi are not wearing the gold for beauty. “There is a biological benefit from this reaction.” Dr. Bohu said, “Gold-loving fungi can grow faster and bigger relative to other fungi that don’t work with gold.”

The researchers still need to conduct further analysis to understand the relationship between the fungi and the precious metal. More importantly, they need to determine if its presence is a sure sign of the existence of large deposits of the metal underground. The scientists also believe the fungi could be used to detect the presence of gold in waste products and man-made electronics.

However, those hoping to get free gold from the fungi are in for a disappointment,for the delicate fungus is hard to see. Also, its gold can only be seen under a microscope.

Based on a new series of experiments, researchers now believe the slower a person’s tendency to walk, the less able their brain.

Researchers performed gait (步态)-speed analysis on hundreds of middle-aged people, comparing the results with a range of physical and psychological measures. Doctors have long used walking speed to gain a quick and reliable understanding of older people’s cognitive capability (认知能力). Until now, however, no one knew it could mean potential brain health so much earlier in life. The correlation was so obvious that the US scientists now say walking tests could be used to provide an early indication of dementia (痴呆).

The study showed an average difference of 16 IQ points between the slowest and the fastest walkers at the age of 45. This reflected both the participants’ natural walking speed and the pace they achieved when asked to walk as fast as they could.

In the study, slower walkers were shown to have “increasing aging” on a 19-measure range designed by researchers, and their lungs and teeth tended to be in worse shape than the people who walked faster.

The team at Duke University in North Carolina said genetic factors may explain the link between walking speed, brain ability and physiological health, or that better brain health might promote physical activity, leading to better walking speed.

“The thing that’s really striking is that this is in 45-year-old people, not the older patients who are usually assessed with such measures.” said Dr. Rasmussen, who led the research. The 904 New Zealand men and women who were tested at 45 were tracked from the age of three, each experiencing many tests over the years. The long-term data collection enabled researchers to find that little kids with lower IQ scores, language ability, ability to tolerate setbacks, tended to have slower gait speeds by middle age.

The researchers said some of the differences in health and cognition may be the result of lifestyle choices individuals have made. But the study also suggests that there are already signs in early life of who would become the slowest walkers. “We may have a chance here to see who’s going to do better health-wise in later life,” said Dr. Rasmussen.

Many animals depend upon sound to find food, detect predators and communicate with one another. These species understandably suffer when loud motorways cut through their habitats. Some deal with this problem by singing more loudly, some change the timing of their calls to occur when fewer people are driving, others just move to quieter places.

It has always been assumed that noise is a problem unique to animals. But a new study by Ali Akbar Ghotbi-Ravandi, a botanist at Shahid Beheshti University in Tehran, has revealed that plants suffer too.

That plants can be affected indirectly by noise pollution has never been in doubt. Since most flowering species depend upon pollinators and most fruit-bearing species need animals to disperse their seeds, it is obvious that if these animal partners are harmed by noise then their botanical plants will do badly, too. What has remained unknown is whether or not plants themselves suffer directly from noise pollution.

Sounds are pressure waves transmitted through gases, liquids and solids. Scientists have previously predicted that plants may be able to sense these waves as they are struck by them. A number of experiments have confirmed this in recent years — plants attacked with ultrasound in the lab have shown a range of hurtful responses, including the expression of stress-related genes, underdeveloped growth and reduced germination (发芽) of seeds.

Working with a team of colleagues, Dr. Ghotbi-Ravandi grew two species in his lab that are commonly found in urban environments. The plants were grown from seeds and allowed to mature for two months in the same space before they were divided into two groups. One group was exposed to 73 decibels (分贝) of traffic noise recorded from a busy motorway in Tehran for 16 hours a day. The other group was left to grow in silence. After 15 days, samples were taken from the youngest fully expanded leaves on every plant in the experiment and studied.

None of the plants exposed to the traffic noise did well. Analysis of their leaves revealed that all of them were suffering. Harmful chemicals in them are indicators of stress in plants and both were found at much higher levels in the plants exposed to the traffic noise. Most notably, levels of the harmful chemicals in the plants exposed to noise were two to three times what they were in those grown in silence. The findings make it clear that the noise of traffic bothers the plants.