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An important hobbit
OPINION LETTERS Energy’s sunny side
From David Ashboren Fred Pearce’s lucid description of thermal solar electricity generation in the Sahara desert (24 October, p 38) mentions three potential drawbacks of the Desertec plan: its location in unfriendly and politically unstable countries, the lack of cooling water where the solar radiation is most intense, and the considerable distance to European consumers. Would it not be possible to locate such a plant on board a suitable raft anchored in the Mediterranean sea, as near to the regions of intense solar radiation as possible? It seems
that at least the drawbacks mentioned would be eliminated. Jerusalem, Israel From Gerry Wolff, Desertec-UK One of the attractions of the Desertec plan is its proposal for a “supergrid” of low-loss high-voltage direct-current transmission lines connecting a range of renewable power sources across a wide area. This would iron out peaks and troughs in supply and demand, and strengthen the security of energy supplies by reducing energy imports into Europe and increasing the diversity of power sources. In addition, international collaborations such as the Union for the Mediterranean’s Mediterranean Solar Plan could help to build good relations among peoples in the region. Applied worldwide, Desertec could be one of the most effective and economical means of cutting carbon dioxide emissions. The German Aerospace Centre (DLR) estimates that by about 2017 electricity from concentrated solar heat will be cheaper than electricity from fossil fuels. Menai Bridge, Anglesey, UK
Enigma Number 1572
Just magic BOB WALKER
66
49
20
37
44
61
78
32
54
Joe has been showing Penny how to calculate the numbers in a 3-by-3 magic square. Each row, column and main diagonal have the same totals. On the left is Penny’s first effort. But she thought it would make a good puzzle if all but one number were in the wrong position. Which number is in its correct position?
WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 6 January. The Editor’s decision is final. Please send entries to Enigma 1572, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to [email protected] (please include your postal address). Answer to 1566 Consistently older: Harry’s current age is 57 The winner Neil Hodgson of Highclere, Berkshire, UK
How time flies From David Sapsford, Department of Anaesthesia, Addenbrooke’s Hospital Douglas Fox’s article explores the idea that we experience time through discrete snapshots of reality, and offers an explanation of why we recall time as having apparently slowed down during stressful events (24 October, p 32). I have long thought that the idea of a snapshot nature of memory also comes into play during the apparent state of unconsciousness we call anaesthesia. It is my conjecture that anaesthesia slows the formation of perceptual memory, possibly by missing out some of the snapshots. In modern anaesthesia there is always some electrical activity in the brain, as complete unconsciousness – where no electrical activity is detected by electroencephalography (EEG) – is impractical and carries higher risks. Patients have been observed to form implicit memories from sounds they experienced while anaesthetised, although they may not be explicitly aware of this being the case (BMJ, vol 309, p 967). Steady-state measurements of the auditory evoked potential (AEP) made using an EEG have been found to peak roughly every 25 milliseconds. This value is close to the neural processing time required for perception that Fox describes in his article. The steady-state AEP frequency has been shown by Jackie Andrade and others to decrease during anaesthesia (Anesthesia & Analgesia, vol 83, p 1279); in other words, the time between peaks increases. If the peaks reflect the formation of perceptual memory snapshots, then replaying the sequence of snapshots at a normal speed would give the effect of accelerated time. It is common for patients recovering from an anaesthetic to think they are about to have
surgery or that it has only been seconds since the start of anaesthesia. The brain has still been active, as evidenced by the observation of implicit recall, but perceptual memory has been stored at a slower rate than normal, such that on waking time is perceived as having passed very rapidly. Cambridge, UK From Alan Chapman Fox’s article suggests that our brain collects more information during times of crisis. Taking this reasoning a step further, if we measure time not by the artificial ticking of a clock but by the passing of significant events, it might go some way to explaining why we often recall time as appearing to have passed more slowly during childhood than in later life. For children, any given period of time will have many new or significant events. As we grow older, and life becomes more routine, we experience fewer new or significant events. Lewes, East Sussex, UK
An important hobbit From Robert Haworth In your interview with Richard Leakey, you report that he steps aside from the debate on whether Homo floresiensis – the “hobbit” – represents a distinct species. Instead, he states that their status is not very important to the story of human evolution (17 October, p 32). In fact, it is fairly well accepted that H. floresiensis is a new hominin species. Every part of it cries out that it is the continuation of something very archaic in human lineage. The implications for theories of the evolution of species, be they hominin or otherwise, are enormous. We now know that up to almost the end of the Pleistocene, four separate species of hominins were walking the Earth: Neanderthals in west 21 November 2009 | NewScientist | 31
For more letters and to join the debate, visit www.NewScientist.com/letters
Eurasia, Homo erectus in southern Asia, H. floresiensis in at least the Sunda islands, Indonesia, and Homo sapiens almost everywhere. This is contrary to the widely held view that closely related species will compete with each other to extinction. Only in the past 10,000 years or so has Earth been populated by a
single human species. Leakey argues that only “a very few individuals” of H. floresiensis have been found. However, as with all reports of fossil types, the key word has been left out: very few have been found – yet. We have only uncovered a fraction of the story of human evolution, and what we have found is hopelessly biased towards regions where it is easy to find fossils, specifically the Rift valley of Africa. Mike Morwood, one of the discoverers of H. floresiensis, is convinced that there are more specimens to be found in southeast Asia and Australasia. The real story of human evolution is just beginning as researchers venture out into more difficult regions to find the evidence. Armidale, New South Wales, Australia
ME or not ME From John Greensmith, ME Free for All.org Your report on Judy Mikovits’s study linking a retrovirus, XMRV, to chronic fatigue syndrome (CFS) (17 October, p 6), along with the longer online article (newscientist.com/article/ 32 | NewScientist | 21 November 2009
dn17947), has elicited cautious optimism in people with myalgic encephalomyelitis (ME). ME has long been written off as malingering or of psychiatric origin, so there are hopes that the study will be replicated and that effective treatments can be suggested. It is widely accepted that CFS and ME are synonymous and interchangeable. In fact, ME is a discrete neurological illness that has been erroneously bundled into the generic CFS diagnostic basket, which contains several illnesses. Psychiatrists admit that these illnesses are heterogeneous and have a variety of causes, yet the confusion over diagnosis creates a situation in which people with ME lose their identity. In light of the new study, psychiatrist Simon Wessely said that ME lies “somewhere between medicine and psychiatry”. In practice, ME, which should be for physicians to treat, has been swallowed up by the catch-all diagnosis of CFS and dragged into the psychiatrist’s clinic. The problem arising from umbrella diagnoses can be illustrated by considering the effect that a clear diagnosis of ME would have on the findings of Mikovits’s study. If every one of the 68 subjects in the sample of 101 people with CFS who tested positive for XMRV had a diagnosis of ME one might come to a different conclusion than if it turned out that none or few of them did. For this reason it is crucial to agree a common universal standard to ensure that we are comparing like with like. If we use a set of diagnostic criteria more likely to include only people with ME, and insist on the same criteria for every attempt at replication, we would be more likely to achieve valid and reliable results for this condition. Bristol, UK From Hayley Klinger, 25%MEGroup While people with ME will be delighted to read that a retrovirus
could be the cause of their devastating and disabling illness, it is disheartening that the media are still going to the psychiatric profession for sound bites on the subject. If the discovery proves anything, surely it is to highlight how totally inappropriate it has been to have had psychiatry involved in the study and treatment of ME for so long. Troon, Ayrshire, UK
Quality not quantity From Trevor Bridges I read with interest Irving Kirsch’s article describing how the antipsychotic drugs given to people with Alzheimer’s disease can shorten their lives (17 October, p 26). The article suggested that this might be a bad thing. My father died of Alzheimer’s disease, and it took nearly 10 years. He progressed from an old-fashioned gentleman, through memory loss, not knowing his own family and aggression, to finally reach an incontinent, vegetative state. The burden on the family was immense and my mother never forgave herself for not being able to look after him until the end, as he had to go into nursing care for the final two or three years. If I go the same way and fail to commit suicide before the illness progresses too far, then the last thing I want is people trying to lengthen my life. So please, please pile on the
antipsychotic drugs and anything else that will shorten my life. Ovington, Northumberland, UK
Previous ITERation From Anthony Fenwick-Wilson I was rather surprised that, when discussing ITER (10 October, p 40), no mention was made of ZETA, the Zero Energy Toroidal Assembly that was built at the UK’s Atomic Energy Research Establishment at Harwell. I remember working at British Thomson-Houston in Rugby on component parts for this experimental fusion reactor in 1957. At the beginning of 1958 it was announced that free neutrons had been produced, and that John Cockcroft, the AERE’s first director, was “90 per cent certain that fusion had occurred”. Unfortunately this was rather premature, and ZETA never did fulfil its promise. The experience gained with ZETA was nevertheless invaluable in pointing the way to later toroidal fusion reactors. These machines are now given the generic description “tokamak”, but ZETA preceded the original Russian reactor of that name. No green energy was produced, but ZETA’s contribution shouldn’t be forgotten. Swansea, UK
For the record ■ We understated the strength of gravity on the surface of Saturn’s moon Titan (7 November, p 44). It is in fact one-seventh that on Earth
Letters should be sent to: Letters to the Editor, New Scientist, 84 Theobald’s Road, London WC1X 8NS Fax: +44 (0) 20 7611 1280 Email: [email protected] Include your full postal address and telephone number, and a reference (issue, page number, title) to articles. We reserve the right to edit letters. Reed Business Information reserves the right to use any submissions sent to the letters column of New Scientist magazine, in any other format.
From David Ashboren Fred Pearce’s lucid description of thermal solar electricity generation in the Sahara desert (24 October, p 38) mentions three potential drawbacks of the Desertec plan: its location in unfriendly and politically unstable countries, the lack of cooling water where the solar radiation is most intense, and the considerable distance to European consumers. Would it not be possible to locate such a plant on board a suitable raft anchored in the Mediterranean sea, as near to the regions of intense solar radiation as possible? It seems
that at least the drawbacks mentioned would be eliminated. Jerusalem, Israel From Gerry Wolff, Desertec-UK One of the attractions of the Desertec plan is its proposal for a “supergrid” of low-loss high-voltage direct-current transmission lines connecting a range of renewable power sources across a wide area. This would iron out peaks and troughs in supply and demand, and strengthen the security of energy supplies by reducing energy imports into Europe and increasing the diversity of power sources. In addition, international collaborations such as the Union for the Mediterranean’s Mediterranean Solar Plan could help to build good relations among peoples in the region. Applied worldwide, Desertec could be one of the most effective and economical means of cutting carbon dioxide emissions. The German Aerospace Centre (DLR) estimates that by about 2017 electricity from concentrated solar heat will be cheaper than electricity from fossil fuels. Menai Bridge, Anglesey, UK
Enigma Number 1572
Just magic BOB WALKER
66
49
20
37
44
61
78
32
54
Joe has been showing Penny how to calculate the numbers in a 3-by-3 magic square. Each row, column and main diagonal have the same totals. On the left is Penny’s first effort. But she thought it would make a good puzzle if all but one number were in the wrong position. Which number is in its correct position?
WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 6 January. The Editor’s decision is final. Please send entries to Enigma 1572, New Scientist, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to [email protected] (please include your postal address). Answer to 1566 Consistently older: Harry’s current age is 57 The winner Neil Hodgson of Highclere, Berkshire, UK
How time flies From David Sapsford, Department of Anaesthesia, Addenbrooke’s Hospital Douglas Fox’s article explores the idea that we experience time through discrete snapshots of reality, and offers an explanation of why we recall time as having apparently slowed down during stressful events (24 October, p 32). I have long thought that the idea of a snapshot nature of memory also comes into play during the apparent state of unconsciousness we call anaesthesia. It is my conjecture that anaesthesia slows the formation of perceptual memory, possibly by missing out some of the snapshots. In modern anaesthesia there is always some electrical activity in the brain, as complete unconsciousness – where no electrical activity is detected by electroencephalography (EEG) – is impractical and carries higher risks. Patients have been observed to form implicit memories from sounds they experienced while anaesthetised, although they may not be explicitly aware of this being the case (BMJ, vol 309, p 967). Steady-state measurements of the auditory evoked potential (AEP) made using an EEG have been found to peak roughly every 25 milliseconds. This value is close to the neural processing time required for perception that Fox describes in his article. The steady-state AEP frequency has been shown by Jackie Andrade and others to decrease during anaesthesia (Anesthesia & Analgesia, vol 83, p 1279); in other words, the time between peaks increases. If the peaks reflect the formation of perceptual memory snapshots, then replaying the sequence of snapshots at a normal speed would give the effect of accelerated time. It is common for patients recovering from an anaesthetic to think they are about to have
surgery or that it has only been seconds since the start of anaesthesia. The brain has still been active, as evidenced by the observation of implicit recall, but perceptual memory has been stored at a slower rate than normal, such that on waking time is perceived as having passed very rapidly. Cambridge, UK From Alan Chapman Fox’s article suggests that our brain collects more information during times of crisis. Taking this reasoning a step further, if we measure time not by the artificial ticking of a clock but by the passing of significant events, it might go some way to explaining why we often recall time as appearing to have passed more slowly during childhood than in later life. For children, any given period of time will have many new or significant events. As we grow older, and life becomes more routine, we experience fewer new or significant events. Lewes, East Sussex, UK
An important hobbit From Robert Haworth In your interview with Richard Leakey, you report that he steps aside from the debate on whether Homo floresiensis – the “hobbit” – represents a distinct species. Instead, he states that their status is not very important to the story of human evolution (17 October, p 32). In fact, it is fairly well accepted that H. floresiensis is a new hominin species. Every part of it cries out that it is the continuation of something very archaic in human lineage. The implications for theories of the evolution of species, be they hominin or otherwise, are enormous. We now know that up to almost the end of the Pleistocene, four separate species of hominins were walking the Earth: Neanderthals in west 21 November 2009 | NewScientist | 31
For more letters and to join the debate, visit www.NewScientist.com/letters
Eurasia, Homo erectus in southern Asia, H. floresiensis in at least the Sunda islands, Indonesia, and Homo sapiens almost everywhere. This is contrary to the widely held view that closely related species will compete with each other to extinction. Only in the past 10,000 years or so has Earth been populated by a
single human species. Leakey argues that only “a very few individuals” of H. floresiensis have been found. However, as with all reports of fossil types, the key word has been left out: very few have been found – yet. We have only uncovered a fraction of the story of human evolution, and what we have found is hopelessly biased towards regions where it is easy to find fossils, specifically the Rift valley of Africa. Mike Morwood, one of the discoverers of H. floresiensis, is convinced that there are more specimens to be found in southeast Asia and Australasia. The real story of human evolution is just beginning as researchers venture out into more difficult regions to find the evidence. Armidale, New South Wales, Australia
ME or not ME From John Greensmith, ME Free for All.org Your report on Judy Mikovits’s study linking a retrovirus, XMRV, to chronic fatigue syndrome (CFS) (17 October, p 6), along with the longer online article (newscientist.com/article/ 32 | NewScientist | 21 November 2009
dn17947), has elicited cautious optimism in people with myalgic encephalomyelitis (ME). ME has long been written off as malingering or of psychiatric origin, so there are hopes that the study will be replicated and that effective treatments can be suggested. It is widely accepted that CFS and ME are synonymous and interchangeable. In fact, ME is a discrete neurological illness that has been erroneously bundled into the generic CFS diagnostic basket, which contains several illnesses. Psychiatrists admit that these illnesses are heterogeneous and have a variety of causes, yet the confusion over diagnosis creates a situation in which people with ME lose their identity. In light of the new study, psychiatrist Simon Wessely said that ME lies “somewhere between medicine and psychiatry”. In practice, ME, which should be for physicians to treat, has been swallowed up by the catch-all diagnosis of CFS and dragged into the psychiatrist’s clinic. The problem arising from umbrella diagnoses can be illustrated by considering the effect that a clear diagnosis of ME would have on the findings of Mikovits’s study. If every one of the 68 subjects in the sample of 101 people with CFS who tested positive for XMRV had a diagnosis of ME one might come to a different conclusion than if it turned out that none or few of them did. For this reason it is crucial to agree a common universal standard to ensure that we are comparing like with like. If we use a set of diagnostic criteria more likely to include only people with ME, and insist on the same criteria for every attempt at replication, we would be more likely to achieve valid and reliable results for this condition. Bristol, UK From Hayley Klinger, 25%MEGroup While people with ME will be delighted to read that a retrovirus
could be the cause of their devastating and disabling illness, it is disheartening that the media are still going to the psychiatric profession for sound bites on the subject. If the discovery proves anything, surely it is to highlight how totally inappropriate it has been to have had psychiatry involved in the study and treatment of ME for so long. Troon, Ayrshire, UK
Quality not quantity From Trevor Bridges I read with interest Irving Kirsch’s article describing how the antipsychotic drugs given to people with Alzheimer’s disease can shorten their lives (17 October, p 26). The article suggested that this might be a bad thing. My father died of Alzheimer’s disease, and it took nearly 10 years. He progressed from an old-fashioned gentleman, through memory loss, not knowing his own family and aggression, to finally reach an incontinent, vegetative state. The burden on the family was immense and my mother never forgave herself for not being able to look after him until the end, as he had to go into nursing care for the final two or three years. If I go the same way and fail to commit suicide before the illness progresses too far, then the last thing I want is people trying to lengthen my life. So please, please pile on the
antipsychotic drugs and anything else that will shorten my life. Ovington, Northumberland, UK
Previous ITERation From Anthony Fenwick-Wilson I was rather surprised that, when discussing ITER (10 October, p 40), no mention was made of ZETA, the Zero Energy Toroidal Assembly that was built at the UK’s Atomic Energy Research Establishment at Harwell. I remember working at British Thomson-Houston in Rugby on component parts for this experimental fusion reactor in 1957. At the beginning of 1958 it was announced that free neutrons had been produced, and that John Cockcroft, the AERE’s first director, was “90 per cent certain that fusion had occurred”. Unfortunately this was rather premature, and ZETA never did fulfil its promise. The experience gained with ZETA was nevertheless invaluable in pointing the way to later toroidal fusion reactors. These machines are now given the generic description “tokamak”, but ZETA preceded the original Russian reactor of that name. No green energy was produced, but ZETA’s contribution shouldn’t be forgotten. Swansea, UK
For the record ■ We understated the strength of gravity on the surface of Saturn’s moon Titan (7 November, p 44). It is in fact one-seventh that on Earth
Letters should be sent to: Letters to the Editor, New Scientist, 84 Theobald’s Road, London WC1X 8NS Fax: +44 (0) 20 7611 1280 Email: [email protected] Include your full postal address and telephone number, and a reference (issue, page number, title) to articles. We reserve the right to edit letters. Reed Business Information reserves the right to use any submissions sent to the letters column of New Scientist magazine, in any other format.