To my dear visitors and commenters

Hi, everybody! I've noticed with lots of joy and happiness, that thousands of comments have been written in my posts. It's wonderful that so may people around the world appreciate my work. Therefore, I want to thank you for that and ,at the same time I want to ask you to be this blog's followers. It's fast and easy! Make it be even more visited and spread all over the world! I'm a woman, a teacher of English in Portugal, and I've been away for quite a long time because of my father's health. Unfortunately he died from Covid19 a few months ago. Now I felt it was time to restart my activity in this and other blogs I owe. I've recently created a new one in a partnership with a street photographer, Mr. Daniel Antunes. He's fabulous! https://pandpbydandd.blogspot.com I'd like you to visit it and, who knows, become our followers. The poems, chronicles and thoughts are all mine. Thank you so much! Kisses :-)

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Saturday, January 17, 2015

Wind power 'adds resilience to UK energy market'

Wind turbine, Scotland (Image: PA)
Installing more wind turbines will make the UK's energy market more resilient to global fossil fuel price shocks, an independent report has concluded.

Dwindling domestic gas and coal supplies mean the nation would become dependent on volatile imports, it adds.The report, by Cambridge Econometrics for RenewableUK, said wind power saved the UK £579 million in fossil fuel costs in 2013.The UK is recognised for having the best wind resource in Europe."One of the main messages from this report is that in a scenario with a higher content of wind energy, you are less reliant on fossil fuels," explained co-author Sophie Billington, a researcher from Cambridge Econometrics.
"This is a key message, particularly when you consider that the UK - for the past five years or so - has imported more gas than it has produced domestically."
She told BBC News that under a high gas scenario (gas power plants replacing end-of-life coal and nuclear plants) and a 40% increase in gas prices by 30%, electricity prices would increase by 8%.However, under a high wind scenario (wind farms replacing end-of-life coal and nuclear plants), electricity prices would still rise but by only 4%.
"For the wind scenario, you have higher upfront capital costs but fewer uncertain variable costs, leading to more price resilience," Ms Billington added.
The report said that the UK electricity sector had undergone a substantial change in recent decades, shifting from a coal-based system to a more balanced mix "encompassing nuclear and gas-fired power stations, as well as emerging renewable energy technologies".
It observed: "Over the next 10 to 20 years, the energy sector will need to be re-shaped again if the UK's targets to reduce CO2 emissions are to be met."
Offshore wind turbine (Image: PA)
The UK is a world leader in offshore wind, with as much generation capacity as the rest of the world combined
In 2008, the UK established the world's first legally binding climate change target, requiring governments to reduce greenhouse gas emissions by at least 80% from 1990 levels by 2050.
Rob Norris, RenewableUK's head of communications, said that currently there were "not enough renewables in the system to meet those targets".
He told BBC News: "The crucial thing is that energy policy is a long-term game and at the moment we only really know what the government support will be out to 2020.
"What you really need is a long-term vision out to 2030 so then you can plan, especially when it comes to things like large offshore developments."
Mr Norris said he advocated a "rich energy mix so then you do not put all your eggs in one basket".
He added: "If you have different technologies, including renewables, competing against each other then the cost is driven down for the consumer."
From BBC Sci/Environement


Friday, January 16, 2015

The geese that can conquer Mount Everest

Bar-headed goose in flight (Photo Nyambayar Batbayar)

A tracking study has revealed the secrets of the Himalayan flight of the bar-headed goose - the world's highest bird migration.
The geese have been recorded at heights of more than 7,000m (23,000 ft) and mountaineers have claimed they have seen the birds fly over Mount Everest.
Their ability to fly in such extreme conditions has fascinated scientists for decades, as the BBC's science reporter Victoria Gill reports. (BBC News)


                    

A pale grey goose with an orange beak and legs and two striking black bars on the head. It lives in central Asia. It is monotypic (males and females look the same) and mates for life.
The bar-headed goose is famous as it is widely believed to make the highest altitude migration on earth. While there was an anecdotal report of a flock of bar-headed geese being heard flying over Mt Makalu (the fifth highest mountain on earth), an unconfirmed report of them being seen flying over Everest has become legend. Such a migration would be incredibly demanding – at altitude the ambient pressure is dramatically reduced, meaning that there is less oxygen available and that the air can support less lift for flight (particularly for species that flap, like geese). This has puzzled biologists and physiologists for years:
"there must be a good explanation for why the birds fly to the extreme altitudes... particularly since there are passes through the Himalaya at lower altitudes, and which are used by other migrating bird species" Black & Tenney (1980).
As part of a large international research project, led by Bangor University and primarily supported by the BBSRC (grant BB/F015615/1) and the Max Planck Institute, bar-headed geese have now been GPS tracked flying over the Himalaya and data reveal that they do not normally fly higher than 6,300 m elevation, flying through the Himalayan passes rather than over the peaks of the mountains. This altitude is clearly still very impressive (equivalent to Everest Camp II) and challenges even the fittest human climbers. Without proper acclimatisation to such altitudes, mammals suffer from high altitude related sickness very quickly, and in some cases this can be fatal.

Bar-headed geese don’t need the wind

It has also been long believed that bar-headed geese use jet stream tail winds to facilitate their flight across the Himalaya. Surprisingly, latest research has shown that despite the prevalence of predictable tail winds that blow up the Himalayas (in the same direction of travel as the geese), bar-headed geese spurn the winds, waiting for them to die down overnight, when they then undertake the greatest rates of climbing flight ever recorded for a bird, and sustain these climbs rates for hours on end.

How can they cope?

Bar-headed geese are known to have a suite of physiological adaptations to help them deal with the low Oxygen (hypoxia) conditions at altitude:
  1. Bar-headed geese have a slightly larger wingspan and lower wing loading than other similar goose species (Lee et al. 2008), yielding greater lift and reducing the power required for flight (Pennycuick 1972).
  2. Their flight muscle is better supplied with fresh oxygenated blood than other waterfowl (Fedde et al. 1985, Snyder et al. 1984, Scott et al. 2009).
  3. Bird lungs are superior to mammalian lungs, having a counter exchange system, which extracts O2 much more efficiently (Ramirez et al. 2007) and they are larger in bar-headed geese than in other species of waterfowl (Scott et al. 2009).
  4. In hypoxic conditions, bar-headed geese can hyperventilate 7.2 times faster than their rate at sea level, and suffer no ill effects as a result of this (which increases blood pH – in humans this makes us restrict blood flow to the brain, causing a dizzy sensation).
  5. Bar-headed geese can also increase cardiac output (heart rate and volume of blood pumped) in hypoxia to 5 times the rate at sea-level when resting (Black & Tenney 1980, although note this can also occur in low altitude bird species too).
  6. Their haemoglobin is also adapted to load more O2 to the blood than most other vertebrates (Hiebl & Braunitzer 1988, Weber et al 1993, Liang et al. 2001).

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