| Lost Garden Cities: Pre-Columbian Life in the Amazon (preview) When Brazil established the Xingu Indigenous Park in 1961, the reserve was far from modern civilization, nestled deep in the southern reaches of the vast Amazon forest. When I first went to live with the Kuikuro, one of the reserve’s principal indigenous groups, in 1992, the park’s boundaries were still largely hidden in thick forest, little more than lines on a map. Today the park is surrounded by a patchwork of farmland, its borders often marked by a wall of trees. For many outsiders, this towering green threshold is a portal, like the massive gates of Jurassic Park, between the present--the dynamic modern world of soy fields, irrigation systems and 18-wheelers--and the past, a timeless world of primordial nature and society.Long before taking center stage in the world’s environmental crisis as the giant green jewel of global ecology, the Amazon held a special place in the Western imagination. Mere mention of its name conjures images of dripping, vegetation-choked jungles; cryptic, colorful and often dangerous wildlife; endlessly convoluted river networks; and Stone Age tribes. To Westerners, Amazonian peoples are quintessential simple societies, small groups that merely make do with what nature provides. They have complex knowledge about the natural world but lack the hallmarks of civilization: centralized government, urban settlements and economic production beyond subsistence. In 1690 John Locke famously proclaimed, “In the beginning all the World was America.” More than three centuries later the Amazon still grips the popular imagination as nature at its purest, home to native peoples who, in the words of Rolling Stone editor Sean Woods in October 2007, preserve “a way of life unchanged since the dawn of time.” [More] rss.sciam.com |
Wipe or Wash? Do Bidets Save Forest and Water Resources? Dear EarthTalk: Wouldn't a return to installing bidets in bathrooms at home go a long way toward cutting disposable tissue use and saving forests? --Peter K., Albany, Ga. [More] rss.sciam.com |
Aristotle's Error Although our perception of the world seems effortless and instantaneous, it actually involves considerable image processing, as we have noted in many of our previous columns. Curiously enough, much of the current scientific understanding of that process is based on the study of visual illusions.Analysis and resolution of an image into distinct features begin at the earliest stages of visual processing. This was discovered in cats and monkeys by a number of techniques, the most straightforward of which was to use tiny needles--microelectrodes--to pick up electrical signals from cells in the retina and the areas of the brain associated with vision (of which there are nearly 30). By presenting various visual targets to monitored animals, investigators learned that cells in early-processing brain areas are each sensitive mainly to changes in just one visual parameter, not to others. For instance, in the primary visual cortex (V1, also called area 17), the main feature extracted is the orientation of edges. In the area known as V4 in the temporal lobes, cells react to color (or, strictly speaking, to wavelengths of light, with different cells responding to different wavelengths). Cells in the area called MT are mainly interested in direction of movement. [More] rss.sciam.com |
At Camp Wah-Nee, the Color War At sleep-away camp, it comes down to this: Color War, a four-day, two-team frenzy of competition and camaraderie. nytimes.com |
California Dreaming? The Golden State Takes the Lead in U.S. Efforts to Combat Climate Change SACRAMENTO--Only two weeks after California voters turned back an effort to suspend the state's program to combat climate change, a cap-and-trade market for greenhouse gas emissions saw its first trade, a swap of a climate-change pollution permit for 2012."While our federal government is sitting on its hands, California is moving full speed ahead to a clean-energy future," Gov. Arnold Schwarzenegger said in his weekly address on November 19 . "We are creating a consistent, long-term energy policy--something that has eluded Washington for decades. In fact, Washington should take a lesson from what is happening right now here in California." [More] rss.sciam.com |