Nothing is a constant in scientific theories. Popular ideas often wind up historical anecdotes. What will happen to these two popular concepts?Snowball Earth Melts: The idea that prior to the emergence of complex life the Earth was frozen over has been given the colorful title, “Snowball Earth.” Scientists at Imperial College, London, are questioning whether this ever happened, according to EurekAlert. They claim to have found evidence of repeated hot and cold cycles that would not have allowed Earth to undergo a prolonged period of freezing. They also questioned it on thermodynamic grounds: “In fact, once fully frozen, it is difficult to create the right conditions to cause a thaw, since much of the incoming solar radiation would be reflected back by the snow and ice.” Antarctic rivers drain Antarctic lakes: Many scientists had speculated that lakes under Antarctic ice might hold pristine clues to the early Earth, and exotic forms of life. Now they may have to take into account a paper in Science1 that found evidence these lakes are connected and drain from one to another as the ice cover shifts. Images from space show that these lakes act like lubricants and rapidly shift the highly-pressurized subglacial ice around. They cited instances: “Large outbursts of subglacial water have been observed in coastal regions,” and “Antarctic subglacial water can move in large volumes between lakes, on short time scales and over long distances.” In conclusion, they remark that the water movements they detected are “large, extensive, and temporally variable.” Big changes were seen within just 2-3 years. “These observations provide clues to understanding the stability of ice streams through their sensitivity to basal lubrication,” they said. “The time scale for subglacial water transport (months to years) is short compared with that of other known drivers of glacial flow variability, suggesting a mechanism for more rapid changes in ice stream behavior than have previously been assumed.”It may be a hard sell, therefore, to claim that anything under the Antarctic remained stable for millions of years – or that we can know with any certainty what the Earth looked like before there were observers.1Fricker, Scambos, Bindschadler and Padman, “An Active Subglacial Water System in West Antarctica Mapped from Space,” Science, 16 March 2007: Vol. 315. no. 5818, pp. 1544-1548, DOI: 10.1126/science.1136897.Didn’t they ever hear of global warming? Indeed, the science wars are heating up all over the world.(Visited 6 times, 1 visits today)FacebookTwitterPinterestSave分享0
Regional manufacturers will be encouraged to reduce pressure on the interconnected SAPP power grid by slowing production during evening peak periods and increasing production during off-peak periods, Eskom said in a statement last week. Eskom’s Project 2010 MD ,Johnny Dladla, said the initiative confirmed that the 2010 Fifa World Cup was “truly an African event”. SAPP members include Eskom, the Botswana Power Corporation, Electricity Supply Commission of Malawi, Empresa National de Electricidade (Angola), Lesotho Electricity Corporation, NamPower (Namibia), Societe National d’ Electricite (Democratic Republic of Congo), Swaziland Electricity Board, Tanzania Electric Supply Company, and Zimbabwe Electricity Supply Authority. 4 May 2009 Some may even take their plants off the grid for planned maintenance when Confederations Cup and World Cup matches are being played. Would you like to use this article in your publication or on your website? See: Using SAinfo material Other initiatives will include ensuring adequate transmission capacity for transfering electricity to South Africa, taking preventative pre-event maintenance, bringing co-generation plants into the SAPP grid, and making more use of renewable energy sources. SAinfo reporter According to the initiative, announced at a meeting of the Southern African Power Pool (SAPP) in Maputo, Mozambique last week, the SAPP’s 12 member countries will conduct a number of power-saving exercises, passing the surplus power created on to South African state company Eskom for use during the 2009 and 2010 football events. South Africa won’t be going it alone when it comes to powering Fifa’s footballing showpiece in 2010. Countries from the southern African region have agreed to a range of measures to help South Africa ensure an uninterrupted World Cup electricity supply. Mozambique’s members are Electricidade de Mozambique, Hydro Cahora Bassa and the Mozambique Transmission Company, while Zambia’s members are the Copperbelt Energy Corporation and Zambia Electricity Supply Corporation. The member countries’ commitment will be backed by commercial agreements, to be negotiated separately between SAPP members and Eskom, that will include targets for the supply of power generated from renewable sources.
Travelers will soon be able to play games, read electronic books and watch videos on their electronic devices throughout the entire flight — not just above 10,000ft – according to a new directive from the US regulator.However the Federal Aviation Administration will not allow the use of mobile phones unless the plane is fitted with a pico cell or receiving station.The ruling follows months of consultation with aviation experts but doubts still remain within the industry.It means passengers can read e-books, play electronic games and watch videos during virtually all phases of flight. The U.S. Federal Aviation Administration says there will only be “very limited exceptions” – such as very low-visibility landings – to the new gate-to-gate policy.The U.S. Federal Communications Commission will still forbid cell phone calls in-flight. That doesn’t change. If your video content is on your smartphone, the device will have to be switched to airplane mode. If the airline on which you’re flying (that means most of them in the U.S.) offers W-Fi, you can use it.Here’s the reason for the move at this time: the Portable Electronic Device Aviation Rulemaking Committee, the ARC, concludes most commercial aircraft can tolerate radio interference generated by PEDs. In a recent report they recommended FAA provide carriers with new procedures so the agency can determine whether their aircraft can handle that radio interference. Once an airline verifies it can, flyers can use the devices gate-to-gate.Low-fare, high-touch JetBlue wants to be the first airline to permit passengers to use PEDs in this fashion. It’s already filed with FAA for the go-ahead. Says JetBlue Chief Commercial Officer Robin Hayes, “The rules have caught up with technology.”But some concerns linger.Pilots have reported a number of cases of suspected electronic interference from passenger’s devices.According to a survey from the International Air Transport Association there were 79 instances of electronic interference between 2003 and 2009.Of those 29 related to mobile phones.Although very rare given the number of flights each year – 36.5 million – reports do suggest that interference can impact every aircraft system.Airlines in the US will now be asked by the FAA to prepare strategies for the implementation of the lifting of the ban below 10,000ft.Delta Air Lines and JetBlue have already announced that they have filed plans with the FAA.Airlines however will also have to demonstrate that their planes can tolerate electronic interference.But the FAA cautioned that “in some instances of low visibility – about one per cent of flights – some landing systems may not be proved PED tolerant, so you may be asked to turn off your device.”The Air Line Pilots Association is cautious.“We remain concerned that relying on passengers to selectively turn off their devices in areas of extremely poor weather is not a practical solution.”In Australia the Civil Aviation safety Authority said it would examine the US decision.
14 August 2014 The government is to partner with the mining industry to further improve the housing and living conditions of mine workers in the country, Minister in the Presidency Jeff Radebe announced on Wednesday. Addressing the third annual Mining Lekgotla gala dinner at Gallagher Convention Centre in Midrand, Johannesburg, Radebe commended the mining sector for working with the government to convert single-sex miners’ hostels into family units. “We believe that this work should be continued with a clear vision of making these family units even more liveable and homely,” Radebe said, adding that mining, as a key economic driver in South Africa, should result in the creation of sustainable communities. “It is envisaged that government will drive the process of improving living conditions for mine workers, with financial support from mining houses.” He also challenged professionals in the mining sector to consider teaching mathematics and science to disadvantaged communities as part of their overall contributions to the development of mining communities. Radebe said the government would also be developing a mining industry initiative as part of Operation Phakisa, the recently launched South African version of the “Big Fast Results” methodology successfully applied by Malaysia, which aims to fast-track the delivery of priorities outlined in the National Development Plan. “We will be planning this Operation Phakisa [initiative] in consultation with all the key stakeholders, including the Chamber of Mines and organised labour.” Mining, Radebe said, remained key to South Africa’s economic growth, with an estimated total contribution to the country’s gross domestic product (GDP), including indirect and multiplier impacts and sectors that rely on mining activities, ranging between 15% and 18%. “It remains a critical source of investment. As a proportion of total gross fixed capital formation, mining’s share was at 12% in 2012,” he said, adding that mining commodities accounted for 46% of exports in the fourth quarter of 2013, while downstream mineral-related manufacturing exports account for another 14%. Radebe said the role of mining had been clearly defined in the recently released Medium Term Strategic Framework, the document that will guide the implementation of the National Development Plan (NDP) over the next five years. “The NDP [National Development Plan] envisages a vibrant economy, which still has the mining sector playing a crucial role. This includes exports and foreign direct investment, production of commodities for energy and/or manufacturing, beneficiation and procurement.” Source: SAnews.gov.za