You may have seen swans performing various synchronised movements or ‘dances’ together on the water at mating time.
The pre-copulatory rituals extend to preening, and although we’re out of the breeding season, this local pair I snapped this afternoon are clearly keeping in practice. Their synchronised stink-eye, reserved for loose dogs and over-eager photographers, is pretty impressive too.
Until last week, I’d only seen the Worcestershire town of Great Malvern from the air. Flying light aircraft in the nineties, one of my favourite sightseeing tours was to head out west from my local airfield near Stratford, turn south over Worcester racecourse towards the Malvern Hills, and watch the sun set over the waters of the Severn estuary.
The ‘Malverns’ are odd. An isolated stretch of peaks, nine miles long and 1394 feet at the highest point. Rising half way up the Eastern side, like a carpet pushed up against a wall, is the town of Great Malvern. In an aeroplane it’s a nice spot to practice steep-banked turns, while distracting your passenger with one of England’s greener and pleasanter views. We mostly got cloud and rain last week – so here’s a view in brighter conditions:
Amongst the famous folk associated with Malvern are C.S.Lewis and J.R.R.Tolkien, whose experiences walking together in the hills, it’s said, fed into their fantasy worlds. For sure, I can see how elves and dwarves might emerge from the cloudy scrumpy cider we sampled at the Unicorn pub – the authors’ favourite after-hike watering hole.
The composer Sir Edward Elgar was a local, and rests with his wife in nearby Little Malvern.
And the private school Malvern College gave many influential political, military, and media people their educational start – including journalist Jeremy Paxman; but not so many scientists or engineers it seems.
That said, it’s a scientist, Charles Darwin, that I associate most strongly with Malvern. A regular visitor from 1849, Darwin made the two-day journey to Malvern to partake of the town’s popular water therapy, hoping it might relieve the chronic vomiting and headaches that plagued him for much of his life (and caused some now think by Chagas’s disease1 contracted on his Beagle voyage to South America). He would later return with his seriously ill daughter Annie.
Ten year old Annie had weakened from scarlet fever over the previous two years, and, with her condition worsening, on 24th March 1851 Darwin made the trip with her to Malvern and Dr James Gully.
Pioneers of hydrotherapy, or hydropathy as they called it, Gully and his colleague James Wilson set up the first of several specialist clinics in the town. Like other spa towns in England, the geographic and economic growth of Malvern was largely driven by the perceived value of its natural waters.
Despite Gully’s efforts, Annie was beyond any water-cure, and Darwin was to leave her in Malvern, permanently, a month later. She died at their lodgings in Montreal House on the Worcester Road, and is buried in the grounds of nearby Great Malvern Priory – literally a stone’s throw from our hotel. Gully described Annie’s condition at death as a “Bilious fever with typhoid character”2; it’s now thought more likely she died from tuberculosis.
From a modern perspective, Gully’s water treatments were doomed to failure. The enthusiastic Gully might wrap a patient in wet sheets, subject them to heavy douches from above and below, or enroll them for a course of ‘spinal washing’.
The core water treatment might be augmented with anything from hill walks to homeopathy, to clairvoyancey, to what amounted to a light baking under oil lamps. Hydropathy’s enthusiastic adoption and questionable effectiveness groups it with the electrical and magnetic treatments popular with Victorian physicians at the time, eager to apply new insights on nature, however misguided, to human well-being.
Perceived benefits were most likely due less to the watery aspects of Gully’s therapy, and more to the generally healthy context of their delivery. Plain eating, abstention from alcohol, and daily exercise in a calming environment could do a lot for a bloated Victorian gentleman. But that didn’t stop Gully and like-minded advocates publishing elaborate treatises and supposedly affirmative case studies4 directly linking water therapy to the cure of all kinds of disease.
Darwin hung in with Gully’s ideas for years before concluding any benefit was limited and purely psychosomatic. He never bought into homeopathy, and seems to have gone along with the more spiritual add-ons from Gully’s palette to keep their relationship. Darwin was open to new ideas, but he always judged them against the standard of reason.
Annie was a special favourite among Darwin’s children, and her death took a lasting toll on his mental state. The poignant memorial he wrote to Annie is here at the Darwin Correspondence Project5
Annie’s story also formed the background to the movie Creation (my earlier review here), with Paul Bettany as Darwin, Jennifer Connelly as his wife Emma, and Bill Paterson as Dr Gully. The film, based on Darwin’s descendent Randal Keynes’s book Annie’s Box, is worth watching if you can forgive a bit of historical license-taking (for one thing, Darwin’s other children don’t age through a series of flashbacks involving Annie). Also, note that the town where they shoot the Malvern scenes, which I can now vouch has the feel of the place, is actually Bedford-on-Avon).
References
1. The Mystery of Darwin’s Ill Health. The Darwin Correspondence Project
2. Darwin
3. Hydropathy, or, The water-cure: its principles, modes of treatment, &c., illustrated with many cases : compiled chiefly from the most eminent English authors on the subject. Shew, Joel, 1816-1855. New York : Wiley & Putnam, 1844. Link to text at U.S. Library of Medicine here.
4. The Water Cure in Chronic Disease. James Manby Gully, M.D., 1850, John Churchill, London
5. The death of Anne Elizabeth Darwin. The Darwin Correspondence Project
6. Note on the IHS monogram here at History from Headstones
Clairvoyance cartoon from George Cruikshank’s Table Book, 1845
Maybe it was the furnace heat of California last month, or the topicality of NASA’s Curiosity landing, but here I am having my first – and almost certainly last – von Däniken moment.
How else though, aside from some ancient Martian visitation, could Native Americans of centuries past, without the benefit of telescopes or interplanetary probes, design water pots so closely matching the Red Planet?
Well, on reflection, I guess a mixture of clay and cactus juice might just bake out that way in the sun.
Which brings us to the real science behind these earthenware pots. Because although they may well be over two hundred years old, discovered in 1926 by my wife’s geologist great-grandfather in the desert of San Diego County, these water carrying olla represent nothing less than the world’s first refrigerator.
The water inside the olla reaches a temperature substantially below that of the surroundings thanks to the principle of evaporative cooling – something you can demonstrate to yourself just by licking a finger and waving it around. The skin feels cooler because the heat needed to turn liquid water molecules in your spit into vapourised water molecules leaving your hand is taken from your skin. The amount of heat, or energy, needed to change from a liquid to a gas is called the latent heat of evaporation, which for water is 2257 kJoules per kilogram.
The sun-baked porous clay of the olla acts like a wick, delivering a constant flow of evaporating water to the surface where it quickly evaporates, cooling first the surface and in turn the water inside the pot.
Wondering how effective ollas really are, but with live tests on our delicate pots off the agenda, I turned to theoretical musings and some (not entirely successful) experimentation.
The Theory
The temperature on the pot’s surface, or wet-bulb temperature, is easy enough to calculate if we know the ambient air temperature, relative humidity (how much water is already in it), and local air pressure – as that affects the dew-point temperature at which water changes from liquid to gas. I got all that info from my local weather station online, and plugged it into one of the many online calculators – like this one at the National Oceanic and Atmospheric Administration (NOAA) – to find the wet bulb temperature. (The exact calculation is complex and explained on the NOAA website, but essentially the drier the air, the lower the wet-bulb temperature; water molecules already in the air decrease the net evaporation rate.)
The day I looked at this, the values were: temperature 34 C, relative humidity 20%, and air pressure 1014.9 millibars, for which the NOAA calculator returned a wet-bulb temperature of about 19 C. That’s a whole 15 degrees below ambient temperature; modern electric fridges don’t do much better than that (okay – granted they can get to lower absolute temperatures).
The wet-bulb temperature I verified experimentally using a cooking thermometer modified with wet paper-towel stuffed in around the sensor tip (a mercury thermometer would have a bulb of mercury at the end – hence wet-bulb; but this was all I had and works well enough). Swinging the thing fast round my head on the end of a shoelace simulated wind and, lo and behold, I recorded a wet-bulb temperature of 21C. Not quite the predicted 19C, but in the right area.
Good ventilation of the olla is necessary as it influences the evaporation rate, and the area for evaporation should be large (the olla’s spherical design is fantastic in this regard as it maximises the area). The area of non-wetted contact should be small to minimise absorption of heat by conduction from the surroundings – here again, the point contact of the spherical olla is perfect. Ollas also work better in the shade, to minimise heating by solar radiation.
Calculating how long the contents take to cool is more tricky, requiring an estimate of the evaporation rate from a porous surface. But we can get some handle on it using an assumed rate of 7kg/m2.day (based on some data I found for swimming pool evaporation rates in Australia of all things), latent heat of evaporation of water 2257 kJ/kg, and heat capacity of water 4.18 kJ/kg.K. From which I reckon the 0.3m diameter olla, holding 14 litres (=14 kg) of water, needs to lose 878 kJ of heat to fall in temperature by 15 degrees, equal to evaporating 0.4 litres (0.4kg or 3% of the contents) from the 0.28 m2 surface over a 5 hour period.
The numbers aren’t perfect, but suggest in its heyday our olla was up and usefully cooling in a couple of hours.
The Practise
Now for the not-totally-successful experimentation part of the post.
You can see what I’m trying to do here: my very own plant pot olla. The physical conditions (temp.,humidity,pressure) were the same as the theoretical calculation; and I’d confirmed a wet-bulb temperature of 22C as described above. The pot was kind of working too; that dark band in the middle and top is water seeping through the porous terracotta – and it was pretty consistent throughout the experiment.
Stirring the contents and taking regular measurements indicated a one degree fall over the first two hours. But then the temperature started to climb again, which suggests the pot was just not porous enough over sufficient area to counter heating by conduction through the non-wetted areas. A lack of wind won’t have helped – maybe use a fan next time. At least no one can accuse me of selectively publishing only positive results.
Other Coolers
The Arab Zeer works in a similar fashion to the olla, but consists of two pots separated by wet sand. Fruit and other perishables can be kept fresh in the central pot.
A modern invention is this Terracooler: an evaporatively cooled terracotta bell-jar placed over food to keep it fresh.
And keep an eye out for artificial waterfalls used to create a cool atmosphere in public spaces, or the same principle operating in simple garden water features: the water in this one I measured at 24C on a 32C day.
I’m back in the UK now, where typical humidity levels close to 100% (=rain) preclude the extensive program of further evaporative cooling tests this discussion clearly signposts. If you have more luck with your own ollas though, do let me know.
You never know what unexpected quirky stuff is going to show up if you keep your eyes open.
This afternoon, Erin and I visited the Pasadena Museum of California Art to see an exhibition of works by Edgar Payne. We’re both fans of American plein-air painting, and Payne was a master of the technique – so the exhibition was a great success. But parking up, we found the Museum’s garage had its own artistic charm.
The graffiti is by artist Kenny Scharf, and instantly caught my eye with its images of rocket ships and swirling galaxies. The garage – or Kosmic Kavern – is the colorful legacy of an exhibition of Scharf’s work in the gallery proper in 2004 – his graffiti in the garage was just never cleaned off! Scharf’s work is influenced by the 1962 animated comedy sit-com The Jetsons, and there are other bits of space and nuclear iconography from the Golden Age of American Science spotted around – like the mushroom cloud and atom-swirl.
Some of the Jetson’s techno-utopia became a reality. But not, unfortunately, the aerocar or three-day week.
More Kenny Scharf
If you’d like to see more of his Kenny Scharf’s work, there’s a good collection at Artsy’s Kenny Scharf Page
Of related interest on Zoonomian
It’s official. Photographing meteors is hard.
Don’t look for meteors in the picture above, because there aren’t any.
My master plan last night, on the 12th August peak of the annual Perseid meteor shower, was to capture in one photograph all the good stuff above: Moon, Venus (bottom left), Jupiter (top) close to Hyades and Pleiades star clusters in Taurus, Orion rising – PLUS a nice Perseid meteor, preferably an exploding fireball, flying through the whole thing.
It doesn’t work like that unfortunately, and, by the time Venus came into view, the meteors had dried up for the night.
Anyhow – I did get something for four hours of clicking and coffee in the dark. The first pic below is actually yesterday’s effort, but the rest were taken this morning between midnight and 4 a.m. outside Los Angeles. A bright hazy sky has reduced the meteor trails to barely visible streaks – but they are there, some with red-green coloration caused by different chemical elements burning off at different times as the meteor enters the atmosphere. Camera and exposure: Canon 7D on tripod unguided, 17mm lens, f.4, 30 seconds, ISO 400-640.
The Perseids are off their maximum now, but will be around for a couple more days if you want to try photographing one yourself. Just point the camera anywhere in the sky after 11 pm or so.
Unless you spent last week vacationing at the bottom of a Titan methane lake, you can’t have failed to notice NASA has just placed its largest, heaviest, and most advanced rover yet – the Mars Science Laboratory, or Curiosity, on the surface of Mars. And ‘placed’ it was – nice and gently – by a rocket powered crane.
Even though I followed the moon landings, the idea of visiting Mars, in any form, still has a ring of science fiction about it. But last weekend at my first Planetary Society Planetfest in Pasadena, California, Mars for me and 1500 others became extra-real, as we stood enthralled and affirmed in the knowledge that, for all our faults, human beings can still pull this stuff off.
There were nail-biting moments and fascinating discussions. What I’ve put together here is a summary from my notes, mixed in with thoughts and photos to give you a taste of what went on.
Let’s set the scene with a JPL simulation of Curiosity’s landing:
And here’s the reaction where I was sitting in the Planetfest crowd:
Now meet four of the Planetary Society team who managed the panels, reported live from JPL, introduced speakers, and generally held things together from Saturday through to Curiosity’s landing late on Sunday evening:
Left to right from top: CEO Bill Nye; Director Projects Dr.Bruce Betts; President Jim Bell; Technology & Scientific Coordinator Emily Lakdawalla.
Arriving early Saturday morning for a front row seat, I knew I was off to a good start when NASA Director of Planetary Science Jim Green sat next to me and slipped me a couple of mission pins.
It also helped that by the time Curiosity touched down we were already Mars experts, thanks to two days of presentations from the likes of ‘Mars Czar’ Scott Hubbard. Hubbard, now an aeronautics professor at Stanford, authored NASA’s ten-year Mars program in which each mission informs and sets direction for future missions under a guiding science strategy of ‘Follow the Water’. That strategy has morphed to ‘Seek Signs of Life’, with the qualification that Curiosity isn’t looking for living life as such, but evidence of past life or conditions that might have supported it (incidentally, there’s an article on this aspect by Stuart Clark here in the Guardian newspaper).
We can follow the sequence. Launched in 1996, Global Surveyor spotted evidence of flash floods, old polar oceans, and water-modified rocks. In 2001, the Odyssey probe detected possible water ice at the pole (using gamma ray spectroscopy), which in 2008 Phoenix confirmed, actually scraping some of it away. The 2004 Mars Rovers, Spirit and Opportunity, also found evidence of historic water in the form of tell-tale hematite ‘berries’. And in 2006, the high-definition imaging ability of the Mars Reconnaissance Orbitor (MRO) convincingly separated out surface features caused by water from those by wind. MRO images were also instrumental in identifying Gale Crater as Curiosity’s landing site. It’s sitting there now, in shake-down mode.
Choosing Gale Crater, said Senior Research Scientist Matt Golombek, as with any landing site, is all about balancing science and safety: a negotiation between scientists who want the rover to go places where it can do interesting science, and engineers who have to build something that will get it there.
Site choice is also iterative with spacecraft development during the build, consistent with a rigorous systems engineering approach that underpins Hubbard’s original strategy and integrates the science/engineering/management teams.
So why choose Gale Crater from what started out as fifty possible landing sites? Firstly, it doesn’t contain many mini-craters for Curiosity to accidentally land and get stuck in; but as importantly, great science waits there in accessible layers of sedimentary rocks stacked up around its central peak – Mount Sharp: layers where we might find signs of an environment for past life.
“The history of Mars is in this hole”
So said Head of Mars Program Doug McCuistion describing how, over the weeks and months, Curiosity will explore the 96 mile wide Gale Crater, moving in on the three-mile high central peak, analysing rocks as it goes – remotely by shooting them with a laser and looking at the emitted light, and by pulling samples into its onboard chem. lab.
Each layer of the ancient deposit at Mount Sharp represents a step back in time, and as the side of the deposit has eroded away, Curiosity doesn’t need long drills to reach them. We may, said Chief Engineer Rob Manning, find evidence of a historic “warm wet Mars”, or even the complex carbon calling cards of past life. Unlike the earlier Spirit and Opportunity rovers – essentially geophysics platforms – Curiosity, with its onboard chem. lab, is equipped to find them.
Curiosity’s driver, Scott Maxwell, used the analogy of backing your car out of the drive with a 15 minute throttle delay for an entertaining introduction to roadcraft on an alien world. The key tip it seems – based on experience with the Spirit rover – is don’t drive to anywhere you can’t see!
After Curiosity?
I guess next to the landing itself, the dominant buzz was around how best to counter a slowdown in the pace of planetary exploration and NASA budget cuts. Crazy as it felt against the euphoria of Planetfest, NASA has no follow-on missions to Mars scheduled after Curiosity (although India plan an orbiter for 2014). [Update 20/08/12, InSight Mars planned for 2016].
In the grand scheme of things, when it comes to actually paying for it, space and planetary exploration simply aren’t a priority for – as one delegate described the general populace – normal people. The Curiosity mission cost every American $7, or I guess about $1 /year. What’s seven bucks? One burger meal? A movie rental?
Science fiction author David Brin echoes the common frustration that we’re not doing enough, fast enough, in space. Where’s the desire? asks Brin, reminding us we have a strong track record of achieving challenging, unlikely, tasks if we really put our minds to it, and pointing to that fairyland in the desert we call Las Vegas.
Asked what it might take for a NASA budget hike to receive more popular support, NASA Deputy Administrator Lori Garver suggested discovery of evidence for extra-terrestrial life or intelligent life might do it, or, less attractively, an asteroid threat to the planet.
It’s not that there are no ideas for a further mission. That would likely involve bringing material back to Earth for detailed analysis by many different laboratories and researchers: a ‘sample return’ mission.
Meantime, the Planetary Society reiterates the case for continued investment to support (America’s) national interest. That includes Bill Nye’s argument for ‘trickle-up economics’, whereby exploration project investments in a region attract the best educators, lift regional and national education standards, motivate a new generation of technology workers – ultimately strengthening a country’s role as an innovation economy (the only sort that has much of a future in my view). That’s before the global economic and political stability benefits to other, if not all, countries stemming from international co-operation in space. These are the kind of messages NASA Adminstator Charles Bolden and JPL Director Charles Elachi endorsed the Planetfest audience to get across to their elected representatives (i.e. Congressmen).
I suspect it also helps to have a few star quality communicators, not to say terminal space enthusiasts, on the case – like Bill Nye, Emily Lakdawalla, and Astronomy Outreach Specialist and Planetfest cheerleader Shelley Bonus :
Commercial Space
Will the future of space be saved by the market? NASA has made extensive use of commercial contractors since before the Apollo program, and now an upswell of new businesses like SpaceX, XCOR, and Virgin Galactic, bringing with them new business models and work cultures, present fresh possibilities.
The role and opportunities for private investment were explored by a panel comprising Andrew Nelson from XCOR, developer of the Lynx low earth orbit rocket plane; George Whitesides, CEO of Virgin Galactic, and your best bet for an early space holiday; Peter Diamandis, founder of the X-Prize, an initiative which, among other things, is in the process of spawning a host of mini-moon-landers; and David Giger of SpaceX, the group whose Dragon capsule in May 2012 hooked up with the international space station. Lynx and Dragon were both on display.
As a trend, relatively well understood processes like taxiing to Earth orbit look likely to migrate almost 100% to commercial interests, leaving NASA and the publicly funded space efforts of other nations to push the exploratory envelope. But it’s not clear-cut. Peter Diamandis reckoned the first manned mission to Mars could be a private venture – and made a bet with Whitesides to that effect (freebie to orbit on Virgin Galactic if he wins).
Private entities can take bigger risks where they’re justified by attractive financial returns. Diamandis believes asteroids will be commercially mined in the next 10-15 years. Some contain precious metals, others carbonaceous chondrites – loaded with hydrogen and oxygen (as water) that, converted to fuel could be stored in space depots; beats lifting every ounce to orbit as we do now. These ideas could revolutionise the fuel logistics of solar system exploration. Science might be coincident with commercial ventures – but it’s still science.
All that said, with private investments apparently self-limited to the hundreds of millions of dollars, not billions, the panel believed public investment is still important.
One company already working with NASA is Sierra Nevada, who were involved building the sky-crane which, when this picture of Executive VP Mark Sirangelo was taken, had yet to lower Curiosity safely on to Mars; so maybe that’s a nervous smile.
But as one of three suppliers chosen to develop launch systems to reach the space station, along with Boeing and SpaceX, Sirangelo can be happy. On a more sombre but celebratory note, Sirangelo presented a tribute to the life of astronaut Sally Ride, who died in July this year.
Manned Missions?
Mentally photoshopping human figures into Martian panoramas is irresistible. And while the debate around the merits of manned versus unmanned exploration trundles on, some folks, like aerospace Engineer, Founder and President of the Mars Society, and author of The Case for Mars
Zubrin, whose enthusiasm alone should get him to Earth orbit, favours the systematic transfer of first unmanned, then manned, modules – for fuel generation, living, etc. – to Mars over a period of years. At least his approach side steps the popular but contentious (and somewhat macho?) debate around who’s ready to hop on a one-way mission. When X-Prize founder Peter Diamantis asked who would volunteer at 75% and 50% risk levels, the show of hands by my reckoning was reserved and super-reserved (although as George Whiteside commented, enough for a crew!) Diamantis reckoned he’d sign up at the 50% risk level. I got the impression from NASA Adminstrator Charles Bolden that he personally supports manned exploration. Further pressure for manned missions comes from advocacy groups such as Artemis Westenberg’s Explore Mars, whose optimistic goal is to see humans on Mars by 2030.
Of course, you can go to Mars in your imagination when you like, a mission delegates at Planetfest prepped for with the help of the Space Art panel. Led by President of the International Association of Astronomical Artists, Jon Ramer, the five space artists discussed the ins and outs of their craft applied to scientific visualisation, fine art, book, and movie work.
Staying with the arts. In tribute to science fiction icon Ray Bradbury, who died in June this year, co-founder of the Planetary Society Louis Friedman, with actor Robert Picardo and space historian Andrew Chaikin, led a poetic tribute to the visionary and sometimes controversial author of The Martian Chronicles.
Diversions and Surprises
Bill Nye may be the CEO of the Planetary Society, but for half an hour on Saturday he donned his trademark lab coat to become 100% ‘Science Guy’ in a liquid nitrogen-fueled double act with actor/director Robert Picardo. The session ended with Bill feeding marshmallows at -370 F to Picardo and young members of the follow-on ‘careers in space’ panel.
Special Guests
A host of special guests appeared on Sunday afternoon, perhaps the most diverting being writer / producer Ann Druyan, who was married to and worked with the late Carl Sagan.
Joined on stage by Family Guy producer Seth MacFarlane, Druyan shared progress on a new thirteen part re-make of Sagan’s famous Cosmos series that will be aired on Fox Network and fronted by Neil Degrasse Tyson.
It’s encouraging that Druyan is staying close to the production, and through MacFarlane aims to maintain the production values and ethos of the original show. Asked whether climate change would be addressed in the updated version, Druyan said it would be – as it was in the original. Also, there would be less emphasis on the nuclear threat. Again in common with the original, efforts will be made to bridge any perceived science-religion divide, perhaps through an appeal to common goals around themes like preservation of the environment. As one delegate put it, Carl Sagan could ‘disagree without being disagreeable’. It will be interesting to see what Tyson does with the Cosmos mantle.
Until Next Year
That’s all folks. All in all a pretty unforgettable weekend. Anyone feeling a bit cynical about space exploration or those who support it would do well to sample one of these gigs. Bill Nye is dead right when he says adventures like Curiosity represent mankind at its best!
Of related interest on Zoonomian
Buck Rogers – A Copper-clad Lesson from History
NASA Jet Propulsion Laboratory
Gee, humans are smart. Never mind the moon landing, today we have these fantastic slide-away pantries to squirrel our stuff away. The ultimate in mall to wall storage efficiency.
Then again, maybe that honor should go to the first of two non-human tidy housekeepers that crossed my path this week: the Acorn Woodpecker (Melanenpes formicivorus):
I’ve written about woodpeckers before – HERE. But this example, snapped in Santa Barbara Zoo (of all places, given the birds are all over the area) is the best example of an acorn-saturated tree trunk I’ve seen. Acorns placed by woodpeckers into holes excavated by woodpeckers – for later consumption.
Tidy Trashlines
Next up, the Trashline Orb Weaver spider (genus Cyclosa). I came across this guy on a pick-your-own blueberry adventure at nearby Gaviota, strung across the bushes. (And vulnerable to accidental picking – it’s likely I ate one of these.):
The spider is the darker lump at the center of the web, hidden among the string of five packages: its ‘trash’, made of bits of old victims, egg sacs, plant material and such like caught in the web. I’d never seen one before, but now I now about them I’ve spotted a couple more in other locations. Here’s one, startled to life below a vertical, albeit incipient, trashline:
Left alone, they pull in their legs and try to look like a piece of trash:
Incidentally, in the top picture you can see a visibly thicker, extra-strong, ‘cross-beam’ section of webbing, the stabilimetum, on which the main web and trashline hangs.
Why go to the trouble? Spider researchers reckon the trashline disguises the spider from approaching food insects, which can then be grabbed more easily; but also hides it from predators ~ a strategy more effective against birds than wasps (ref 1).
Yeah, we’re smart – in some things; but we’re not the whole story by a long shot.
Of related interest
‘Decorative Spider Webs Attract Dinner‘ (BBC item from 20/9/12)
References and further reading
1. Detritus decorations of an Orb-Weaving spider (Cyclosa mulmelnensis): for food or camouflage ? Tan E. & Li D., Journal of Experimental Biology, 2009, DOI 10.1242/jeb 030502 (pdf here)
3. Trashiline Orb Weaver – A cool spider (abundantnature.com)
Photos copyright Tim Jones
Between 2006 and 2010, half a million 40-69 year olds, including yours truly, joined the UKBioBank project. We agreed to share lifestyle and medical information – not to mention blood, saliva, and urine samples – all to help researchers get a better handle on the incidence, cause, and treatment of disease. With enough subjects, the logic goes, associations between an individual’s characteristics and their health can inform our understanding and treatment of the wider population.
No surprise then that only a few pages in to Misha Angrist’s Here Is a Human Being: At the Dawn of Personal Genomics
Clearly, there must be differences, otherwise I’d have got to write the book and hang out with the likes of Stephen Pinker – with Angrist settling for the return bus fare to a medical testing center in Croydon. The distinction is mainly down to issues of privacy, plus the fact that Angrist’s genome was sequenced when it was still a big expensive deal to do that.
UKBiobank data is anonymised. Even the researchers working with my genome (if and when it’s ever sequenced) won’t know my name . Angrist’s PGP data, however, is public: genome, life style, medical history; it’s just out there – totally, with his name on it. To take part in PGP you have to take an exam to show you know what you’re doing; those in the spearhead PGP-10 group required a Masters level training in genetics. More importantly, as Angrist gets to see his own stuff under the PGP rules, he can share the motivations, emotions, excitement and anxieties that go with that kind of exposure and self-knowledge. (How effective promises of confidentiality in programs that have them really are is a whole different, but related, topic.)
Human genomics is a young field. The first composite human genome was published by the U.S. government’s Human Genome Project (HGP) in 2003. A parallel commercial project led by Craig Venter and the Celera Corporation published Venter’s personal genome in 2007. Early processes were slow and costs correspondingly high; but the promise, particularly for medicine, was great. Now, as the dream of a medical revolution fades, and free-falling costs open the way for mass genomic profiling, attention has turned more to protecting the public from what some see as a useless, possibly dangerous, product of an immature science – peddled by an exploitative industry. Insurance companies circle round the latest hot tool for risk minimisation, ready to turn our genome against us. Bridging the exclusive and commodity phases on the human gemonics timeline, Angrist brings an insiders eye to bear on an uncertain period. As he says “I had arrived at the theatre early enough to grab a good seat, but the carpenters were still building the sets.”
It’s fashionable to talk about personal genomics in terms of its profound complexities and limitations, and not its useful applications. You can see why though. In predicting disease, genes tell only part of the story alongside environmental factors. As Angrist says, we need to link environment (was a child exposed to lead paint), phenotype (how much did it weigh), and lifestyle (what did I have for breakfast) with personal genomic profiles. He cites rheumatoid arthritis as an example where from twin studies we know the risk is only 50% genome related. Disease is sometimes associated with single defective genes, but more often is the combined expression of many genes interacting with each other and the environment. Relevant genes may exist anywhere throughout the genome, requiring researchers to search the whole smash – with no clues on appearance or location. To complicate things further, the same disease is caused by different gene combinations in different people.
That’s not to say some genetic associations don’t give personal genome candidates pause for thought. When, in a separate study, James Watson’s genome was sequenced, he chose not to know his risk of the incurable Altzheimer’s disease; Angrist’s fellow PGPer Stephen Pinker made the same choice. As interesting perhaps is the fact that many people do want to know their Altzheimer’s risk – despite the disease’s incurability, and that studies show they can handle the knowledge. Angrist has a special interest in the breast cancer gene variants BRCA1 and BRCA2, as his daughters would be at an 80% life-time risk were he to pass on defective versions; it seems personal genomes aren’t so personal after all. In one of the most human moments in the book, Angrist sits alone with his genome report, about to discover this type of information for the first time.
Angrist is at pains to show where human genomics contributes beyond disease prediction, pointing to work on: drug efficacy across ethnic groups and individuals (testing for hyper-sensitivity to warfarin blood thinner), resolution of paternity disputes (10% of fathers are not biological), donor screening (of blood and sperm), and identification of lost racial origins or heritance. One company specialises in providing genome-based nutritional advice, perhaps advising someone whose gene mix inhibits calcium absorption to consider taking a supplement. Ethically intriguing applications include the use of genetic selection to identify our ideal partner or love match. These on top of the widely used law enforcement applications of DNA we know and love from TV shows like CSI.
Angrist weaves plenty of historical, technical, and commercial detail into his personal story, much of it original and drawn from interviews with fellow PGP’ers (a truly mixed bag of characters and motivations in their own right), PGP Founder George Church, and a host of specialists in genomics and medicine – including some insightful tid-bits from former HGP Director Francis Collins and James Watson.
You won’t retain it all – I sometimes lost track of who exactly developed what, when, and where; who went bust and reappeared again, etc. – but the main take-away is clear enough. That despite any limitations and historical hype – “the marketing of personal genomics has outpaced the science” – personal human genomics is far from valueless, and has great potential if we hang in with it. Specifically, Angrist believes the tangled complexity of genotype-phenotype associations may unravel if a sufficiently large sample of cross-referenced data is available. And with over a thousand active participants in the PGP in 2012, and thousands more in the queue, it looks like that might just happen.
RECOMMENDED.
Misha Angrist blogs at GenomeBoy.
Also of interest:
http://thednaexchange.com/2013/11/29/the-fda-calls-a-penalty-on-23andme/
How when we dig up a dinosaur bone do we know it comes from a young animal or a smaller example of a different species? That’s a question the Museum of Natural History of Los Angeles collection of T.rex helps answer.
Yesterday, Erin and I visited the new Dinosaur Hall, where for the first time fossilised skeletons of three complete Tyrannosaurs are brought together to illustrate the different stages in the animal’s development.
Above you see the three who died at 17 yrs, 14 yrs, and 2 yrs.
Here’s the largest, Thomas, as he looked a couple of years back when we last visited the museum: encrusted in rock, but the star all the same of his own very public extraction in the Dino Lab:
Comparing the three, we see that Tyrannosaurs don’t just scale up uniformly as they grow. The eye sockets, for example, are more rounded in babies, changing to a keyhole shape in the adult. The accompanying texts to the display explain how the relative length of the foot bone to the leg decreases from 70% to 50% from 2 to 17 yrs.
On a lighter note. Ever wondered what a Tyrannosaurus rex looks like with (most of) its bones missing? Probably not I guess, but here it is:
This was a bit of fun we got roped into: a Tyrannosaur puzzle no less. The bones of the T.rex are taken off the frame, and it’s up to us non-experts to put them back in the right place. It’s harder than you might think – and it makes you think! (Shh – that’s the point).
I got off to an easy start with those deceptively unimpressive fore-limbs we all know and love from Jurassic Park, but soon came to grief when it came to the ribs. Best leave things to the experts:
Assembling a Tyrannosaur is just like working on your car: there’s always an extra piece left over when you put it back together……
Great exhibition and well recommended. Thanks to NHMLA for an enjoyable afternoon.
Meet the Grease Ants (Solenopsis molesta). Smallest ants I’ve ever seen. One or two millimetres long, they look like specks of dust at first glance, but on closer inspection are perfectly formed little ants. This bunch is a minor infestation running around the kitchen surface where I’m staying in California – or rather an ex-infestation, as I’m afraid we had to zap them. Native to most parts of the U.S.A. – for sure we don’t have anything like this in Surrey – they’re also known as thief ants for their behaviour of stealing food from other ant colonies. They also like grease. The UK 20p piece is for size comparison – it’s about the size of a U.S. nickel.
Naturally, there’s also a Grease Ant Movie. Shot in low light with the iPad camera, so excuse the less than National Geographic production values:
