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January 13, 2010

What calendars were used in the BCE eras?

Notes and queries: How they counted the years in the BC era; what noise does a giraffe make? | From the Guardian | The Guardian
The Roman calendar was counted Ab urbe condita ("from the foundation of the city"), in 753 BC; and it continued in use until the Anno Domini calendar was introduced in AD 525. The monk who calculated AD from AUC forgot that the Emperor Augustus ruled for four years as Octavian before he changed his name, and this error remains in the system. Also, as he counted in Roman, not Arabic, numerals, he did not include the years 0 BC and AD 0. The Muslim calendar runs from the Hijra, Muhammad's flight from Mecca to Medina in AD 622. Like the Christian calendar, it displaced earlier calendars such as the Zoroastrian one in Persia, which dates from about 1200 BC. The Muslim calendar is a lunar one, but Iranians still celebrate Nowruz, the new year in the solar Zoroastrian calendar, at the spring equinox each March. The Chinese calendar dates back to about 2700 BC and the Hindu calendar to about 3100 BC. The Jewish calendar has an even earlier starting point, 5,770 years ago, calculated as the date of the creation as described in scripture. . . .

January 12, 2010

Scientists plan a water-purifying boat to troll the rivers of Europe

Biotech Water-Purification Boat To Make The Rivers Of Europe Drinkable
A passenger vessel the size of a whale and packed with gardens, the concept ship Physalia is also designed to purify every river it floats in. Keep the Physalia in your river for long enough, and it will create drinkable water. Created by Vincent Callebaut Architects, the ship is called Physalia and is intended to float upon some of the most famous rivers of Europe, cleansing them and making their water drinkable.

January 11, 2010

How water can start a forest fire

Water Drops Magnify Sunlight and Burn Leaves | LiveScience
Many gardeners swear you should not water in the midday because water droplets on plants can magnify the sun's rays and burn leaves. But the idea has never been rigorously tested, until now. "This is far from a trivial question," said biophysicist Gabor Horvath at Eotvos University in Budapest, Hungary. "The prevailing opinion is that forest fires can be sparked by intense sunlight focused by water drops on dried-out vegetation." Horvath and colleagues used both experiments and computer modeling to figure out the physics that goes on. The results varied depending on the type of leaf. On smooth surfaces, such as a healthy maple leaf, no leaf burn occurred. But on leaves with small wax hairs, such as those of the floating fern, the hairs were able to hold water droplets above the leaf surface, creating a magnifying-glass effect that gave the leaves a noticeable sunburn — though no open flames resulted.

Fighting the Red Devils--the Humboldt Squid--in the Pacific

Doing battle with the red devils of the Pacific - life - 11 January 2010 - New Scientist
This beast is angry, and has flashed from white to a deep maroon. It's nearly 1.5 metres long, including the tentacles, which flail in Stewart's hair until she can offload the catch into a cooler filled with seawater. That only gives the squid ammunition, as it can now fire a powerful jet of water and ink at anyone who strays into its sights. "Ink in your eye stings," warned Stewart earlier. She is also careful to avoid the animal's sharp beak, which can deliver a nasty bite. Within a minute or so, Stewart and her colleague John Field of the US National Oceanic and Atmospheric Administration have attached an electronic device to one of its fins. It's time to return the devil to the depths. We are out on the Fulmar on this bright December day to learn about the animals' movements. When the device detaches and surfaces, it should send a radio signal to reveal its location, and transmit data revealing how the animal has been migrating up and down in the water. This is key to understanding why the Humboldt squid (Dosidicus gigas) has invaded the waters off central California, and how it may affect the region's valuable fisheries.