IIRC, there have been experiments at JPL in which bacteria were subjected to ever more Martian-like conditions, and that if the environmental change was slow enough, some bacterial successfully adapted. My brief search didn't turn up those experiments. However...
During the assembly of the Phoenix spacecraft (http://en.wikipedia.org/wiki/Phoenix_(spacecraft)) cultures taken from the clean room in which the spacecraft was assembled and tested noted a shift in the organisms cultured towards those capable of surviving UVC radiation and hydrogen peroxide exposure. The shift towards these extremophiles is notable because Mars has UVC radiation at its surface, and plenty of peroxide species in its soil. The authors of this study speculate that the shift to extremophiles in the clean room was brought about by spacecraft cleaning procedures. Study: "Recurrent Isolation of Extremotolerant Bacteria from the Clean Room Where Phoenix Spacecraft Components Were Assembled", ASTROBIOLOGY Volume 10, Number 3, 2010, DOI: 10.1089/ast.2009.0396
Abstract: The microbial burden of the Phoenix spacecraft assembly environment was assessed in a systematic manner via several cultivation-based techniques and a suite of NASA-certified, cultivation-independent biomolecule-based detection assays. Extremotolerant bacteria that could potentially survive conditions experienced en route to Mars or on the planet’s surface were isolated with a series of cultivation-based assays that promoted the growth of a variety of organisms, including spore formers, mesophilic heterotrophs, anaerobes, thermophiles, psy- chrophiles, alkaliphiles, and bacteria resistant to UVC radiation and hydrogen peroxide exposure. Samples were collected from the clean room where Phoenix was housed at three different time points, before (1P), during (2P), and after (3P) Phoenix’s presence at the facility. There was a reduction in microbial burden of most bacterial groups, including spore formers, in samples 2P and 3P. Analysis of 262 isolates from the facility demonstrated that there was also a shift in predominant cultivable bacterial populations accompanied by a reduction in diversity during 2P and 3P. It is suggested that this shift was a result of increased cleaning when Phoenix was present in the assembly facility and that certain species, such as Acinetobacter johnsonii and Brevundimonas diminuta, may be better adapted to environmental conditions found during 2P and 3P. In addition, problematic bacteria resistant to multiple extreme conditions, such as Bacillus pumilus, were able to survive these periods of increased cleaning. Key Words: Phoenix—Extremotolerant—Clean room—Spacecraft assembly facility. Astro- biology 10, 325–335.
I went to the link, and saw the PhotoBlocker product line. Interesting. But I get a 404 error on all of their "buy" buttons. Even more interesting..../adjusts tinfoil hat/
as demonstrated by the Merrit Island National Wildlife Refuge (http://kennedyspacecenter.com/wildlife-refuge.aspx), which includes Kennedy Space Center. Gotta say, when I watched the SpaceX launch last week, I didn't notice any 'gators running away in panic. Five minutes after the launch, the frogs were ribbiting just as loudly as before liftoff. In TX I suppose it will be 'dillos, and I doubt they'll notice launch operations any more than KSC's wildlife has over the decades of launch operations there.
Good question. One of the great things about silicon from a device manufacturing perspective is that it forms an insulating oxide. Don't know if silicene will do that without compromising its desirable electronic properties. Maybe some of the modelers among us can tell what will happen to the electron structure when we start plugging oxygen atoms onto silicene?
"Because of its unique physical properties, graphene, a 2D honeycomb arrangement of carbon atoms, has attracted tremendous attention. Silicene, the graphene equivalent for silicon, could follow this trend, opening new perspectives for applications, especially due to its compatibility with Si-based electronics. Silicene has been theoretically predicted as a buckled honeycomb arrangement of Si atoms and having an electronic dispersion resembling that of relativistic Dirac fermions. Here we provide compelling evidence, from both structural and electronic properties, for the synthesis of epitaxial silicene sheets on a silver (111) substrate, through the combination of scanning tunneling microscopy and angular-resolved photoemission spectroscopy in conjunction with calculations based on density functional theory."
This is from Phys Rev Letters (DOI: 10.1103/PhysRevLett.108.155501
they show reasonably convincing LEED (low energy electron diffraction) and STM (scanning tunneling microscope) images of the putative hexagonal close packed array of Si atoms.
It doesn't. It's an American corporation. It's highest priority under American law is maximization of shareholder value. Given that initial condition, it's pretty easy to predict this outcome. If we want to change the outcome, we have to change the legal conditions under which American corporations operate.
Basically, titanium isotope signatures from Earth and lunar samples are identical. For the giant impact theory to be correct, the impactor would have had to have the same titanium isotope mix as Earth, which seems unlikely if it originated elsewhere/when in the solar system's formation. But as usual, it's complicated. See the article and stay tuned...
Thanks for that info. Non-aqueous solvent systems would be consistent with the water diffusion work, and would be very, very useful. It would be a big deal to be able to do TEM on a liquid system.
TFA seems inconsistent with a recent report that graphene is so transparent to water than one can in effect use a graphene barrier to selectively out-diffuse water. (http://biology-forums.com/index.php?topic=18349.0;topicseen) gives a popularized account of the original work that indicates you can concentrate alcohol in alcohol/water solutions by simply putting a graphene film bottlecap on the bottle. Yahoo! for those of us who want to make EverClear from vodka, I guess.
So if this story is talking about using graphene to enable TEM examination of aqueous systems, I don't see why the water doesn't diffuse rapidly out of the graphene bubble boundary, especially given the tiny volumes that would be involved in a TEM specimen.
The graphene water diffusion paper is "Unimpeded Permeation of Water Through Helium-LeakTight Graphene-Based Membranes", paywalled at Science Mag. Really interesting.
No, I don't think they'll bring down an airliner, but I'm pretty sure they would have no qualms about putting their critics on the no-fly list. Probably doesn't take much to get on that list, and it's really difficult to get removed.
"Cohort studies demonstrating association do not necessarily imply causality, but the preferable randomised controlled trial method for assessing hypnotic risks may be impractical due to ethical and funding limitations."
It's well-known that sleep disturbances are correlated with higher mortality. This study could simply be uncovering that people who have sleep disturbances (and who are therefore in a higher mortality group) are more likely to ask for meds to help them sleep. Can't see that there's any big news here.
Not having read the research, I feel unencumbered by facts so I'll speculate. Irresponsible, I know, but such fun!
Maybe it wouldn't take an X-ray excitation source if a lower energy source were bright enough. I presume there's some energy transition in the Ne electronic structure that SLAC's X-ray flashlight pumps to make the coherent X-ray emission they seek. Maybe the X-ray pump is high enough energy that each X-ray photon has enough energy to pump the Ne transition. This sounds like linear absorption to me. So the question is, can this transition be pumped by photons of lower energy that individually don't have the energy to excite whatever transition in neon's electronic structure that gives them the X-ray output?
Maybe.
If two (or more?) photons, each of which has less energy than is needed to excite an absorption mechanism, arrive at the potential absorber within a sufficiently short time, and if th sum of the two photons' energies is greater than that needed to effect excitation, the excitation can happen. See "two photon absorption".
So perhaps, if you had a source of low energy photons that was bright enough (enough photons/unit time), multiple photon mechanisms might pump a Ne X-ray laser. Maybe we wouldn't have to have SLAC to make it happen.
Don't know if this is possible or practical. I think it's possible, but I think the absorption probabilities are pretty low so it would take a hella bright low energy source to match the SLAC X-ray pump flashlight re Ne excitation rate.
I'd be delighted if somebody who actually knows about this stuff could set me straight.
If so, it's not revolutionary, but a good application of an old coating technology. When I get my iPhone 5, I'll probably send it to these guys for coating.
If you do, and you haven't discovered Elizabeth George, you have a treat in store. Her stories are intelligent, complex, and engrossing. You can jump in at any point in the series, but as each builds on the prior ones, I really recommend you start with the first, "A Great Deliverance". Have fun on your travels!
Methadone's pharmacokinetics give it a long half-life, and therefore a long duration of action. This is an asset in managing chronic pain from cancer and some other diseases. Methadone has much less tendency to lose its analgesic effect through habituation. Morphine, for example, while an effective pain reliever due to its action on the mu-opioid receptor, has a metabolite that acutally upregulates perception of pain due to action on the NMDA system. This latter effect probably accounts for most of the often-observed dose escalation needed to maintain effective analgesia in patients treated with morphine. The primary danger of methadone is that physicians who are unaware of its comparitively slow pharmacokinetics overdose their patients because they escalate the dose too fast. It is critical to make changes (either increase or decrease) in methadone dosage *slowly* - when that is done, the drug can provide chronic pain relief with a much better combination of safety and long-term effectiveness than many of the other opiates. As always, ignorance seems to be the most deadly disease.
For example - the idea of a time machine has been around for a long time, at least since H.G. Wells wrote about it. If I could *actually* build one....that would absolutely be patentable. It isn't the idea that's patentable, it's how to do it. If, of course, the "how to do it" is novel, useful, and non-obvious.
Interesting you mentioned that. My wife's uncle (in his 80s now) went to Stanford Medical School literally right out of high school on the strength of his grades and a 10 minute interview with the school's Chief of Surgery. He went on to become one of the country's most accomplished chest crackers (thoracic surgeon) and did all manner of good, high-level work in his career. Right out of high school. That could never happen today, although not because the raw material is less talented than in his day.
Slashdot Mirror
IIRC, there have been experiments at JPL in which bacteria were subjected to ever more Martian-like conditions, and that if the environmental change was slow enough, some bacterial successfully adapted. My brief search didn't turn up those experiments. However...
During the assembly of the Phoenix spacecraft (http://en.wikipedia.org/wiki/Phoenix_(spacecraft)) cultures taken from the clean room in which the spacecraft was assembled and tested noted a shift in the organisms cultured towards those capable of surviving UVC radiation and hydrogen peroxide exposure. The shift towards these extremophiles is notable because Mars has UVC radiation at its surface, and plenty of peroxide species in its soil. The authors of this study speculate that the shift to extremophiles in the clean room was brought about by spacecraft cleaning procedures. Study: "Recurrent Isolation of Extremotolerant Bacteria from the Clean Room Where Phoenix Spacecraft Components Were Assembled", ASTROBIOLOGY
Volume 10, Number 3, 2010, DOI: 10.1089/ast.2009.0396
Abstract: The microbial burden of the Phoenix spacecraft assembly environment was assessed in a systematic manner via several cultivation-based techniques and a suite of NASA-certified, cultivation-independent biomolecule-based detection assays. Extremotolerant bacteria that could potentially survive conditions experienced en route to Mars or on the planet’s surface were isolated with a series of cultivation-based assays that promoted the growth of a variety of organisms, including spore formers, mesophilic heterotrophs, anaerobes, thermophiles, psy- chrophiles, alkaliphiles, and bacteria resistant to UVC radiation and hydrogen peroxide exposure. Samples were collected from the clean room where Phoenix was housed at three different time points, before (1P), during (2P), and after (3P) Phoenix’s presence at the facility. There was a reduction in microbial burden of most bacterial groups, including spore formers, in samples 2P and 3P. Analysis of 262 isolates from the facility demonstrated that there was also a shift in predominant cultivable bacterial populations accompanied by a reduction in diversity during 2P and 3P. It is suggested that this shift was a result of increased cleaning when Phoenix was present in the assembly facility and that certain species, such as Acinetobacter johnsonii and Brevundimonas diminuta, may be better adapted to environmental conditions found during 2P and 3P. In addition, problematic bacteria resistant to multiple extreme conditions, such as Bacillus pumilus, were able to survive these periods of increased cleaning. Key Words: Phoenix—Extremotolerant—Clean room—Spacecraft assembly facility. Astro- biology 10, 325–335.
I went to the link, and saw the PhotoBlocker product line. Interesting. But I get a 404 error on all of their "buy" buttons. Even more interesting.... /adjusts tinfoil hat/
as demonstrated by the Merrit Island National Wildlife Refuge (http://kennedyspacecenter.com/wildlife-refuge.aspx), which includes Kennedy Space Center. Gotta say, when I watched the SpaceX launch last week, I didn't notice any 'gators running away in panic. Five minutes after the launch, the frogs were ribbiting just as loudly as before liftoff. In TX I suppose it will be 'dillos, and I doubt they'll notice launch operations any more than KSC's wildlife has over the decades of launch operations there.
Good question. One of the great things about silicon from a device manufacturing perspective is that it forms an insulating oxide. Don't know if silicene will do that without compromising its desirable electronic properties. Maybe some of the modelers among us can tell what will happen to the electron structure when we start plugging oxygen atoms onto silicene?
"Because of its unique physical properties, graphene, a 2D honeycomb arrangement of carbon atoms, has attracted tremendous attention. Silicene, the graphene equivalent for silicon, could follow this trend, opening new perspectives for applications, especially due to its compatibility with Si-based electronics. Silicene has been theoretically predicted as a buckled honeycomb arrangement of Si atoms and having an electronic dispersion resembling that of relativistic Dirac fermions. Here we provide compelling evidence, from both structural and electronic properties, for the synthesis of epitaxial silicene sheets on a silver (111) substrate, through the combination of scanning tunneling microscopy and angular-resolved photoemission spectroscopy in conjunction with calculations based on density functional theory."
This is from Phys Rev Letters (DOI: 10.1103/PhysRevLett.108.155501
they show reasonably convincing LEED (low energy electron diffraction) and STM (scanning tunneling microscope) images of the putative hexagonal close packed array of Si atoms.
It doesn't. It's an American corporation. It's highest priority under American law is maximization of shareholder value. Given that initial condition, it's pretty easy to predict this outcome. If we want to change the outcome, we have to change the legal conditions under which American corporations operate.
Thanks
The giant impact lunar origin theory got a little less likely just recently. The original article in Nature Geoscience is behind a paywall, but you can read a summary at http://www.space.com/15035-moon-formation-theory-challenged.html.
Basically, titanium isotope signatures from Earth and lunar samples are identical. For the giant impact theory to be correct, the impactor would have had to have the same titanium isotope mix as Earth, which seems unlikely if it originated elsewhere/when in the solar system's formation. But as usual, it's complicated. See the article and stay tuned...
Wish I had mod points for you. Maybe if I make a Sprinkled Parmesan sacrifice to His Noodlyness, I'll get some....
A graphene baklava: wonderful image, thank you. It amazes me that a structure that won't allow helium to diffuse lets water pass easily. Who'da thunk?
Thanks for that info. Non-aqueous solvent systems would be consistent with the water diffusion work, and would be very, very useful. It would be a big deal to be able to do TEM on a liquid system.
TFA seems inconsistent with a recent report that graphene is so transparent to water than one can in effect use a graphene barrier to selectively out-diffuse water. (http://biology-forums.com/index.php?topic=18349.0;topicseen) gives a popularized account of the original work that indicates you can concentrate alcohol in alcohol/water solutions by simply putting a graphene film bottlecap on the bottle. Yahoo! for those of us who want to make EverClear from vodka, I guess.
So if this story is talking about using graphene to enable TEM examination of aqueous systems, I don't see why the water doesn't diffuse rapidly out of the graphene bubble boundary, especially given the tiny volumes that would be involved in a TEM specimen.
The graphene water diffusion paper is "Unimpeded Permeation of Water Through Helium-LeakTight Graphene-Based Membranes", paywalled at Science Mag. Really interesting.
"Author should have wrote: "A kiloton is equivalent to 4.184 gigajoules""
Actually, a KT is equivalent to 4.184 terajoules. One ton is equivalent to 4.184 gigajoules...Wikipedia is your friend, you're welcome.
give an increase in the incidence of autism over time if there is a genetic component to the disorder?
No, I don't think they'll bring down an airliner, but I'm pretty sure they would have no qualms about putting their critics on the no-fly list. Probably doesn't take much to get on that list, and it's really difficult to get removed.
And the authors recognize this - from TFA:
"Cohort studies demonstrating association do not necessarily imply causality, but the preferable randomised controlled trial method for assessing hypnotic risks may be impractical due to ethical and funding limitations."
It's well-known that sleep disturbances are correlated with higher mortality. This study could simply be uncovering that people who have sleep disturbances (and who are therefore in a higher mortality group) are more likely to ask for meds to help them sleep. Can't see that there's any big news here.
Would this (http://dl.tribler.org/download.html) be something like what you're thinking of?
Not having read the research, I feel unencumbered by facts so I'll speculate. Irresponsible, I know, but such fun!
Maybe it wouldn't take an X-ray excitation source if a lower energy source were bright enough. I presume there's some energy transition in the Ne electronic structure that SLAC's X-ray flashlight pumps to make the coherent X-ray emission they seek. Maybe the X-ray pump is high enough energy that each X-ray photon has enough energy to pump the Ne transition. This sounds like linear absorption to me. So the question is, can this transition be pumped by photons of lower energy that individually don't have the energy to excite whatever transition in neon's electronic structure that gives them the X-ray output?
Maybe.
If two (or more?) photons, each of which has less energy than is needed to excite an absorption mechanism, arrive at the potential absorber within a sufficiently short time, and if th sum of the two photons' energies is greater than that needed to effect excitation, the excitation can happen. See "two photon absorption".
So perhaps, if you had a source of low energy photons that was bright enough (enough photons/unit time), multiple photon mechanisms might pump a Ne X-ray laser. Maybe we wouldn't have to have SLAC to make it happen.
Don't know if this is possible or practical. I think it's possible, but I think the absorption probabilities are pretty low so it would take a hella bright low energy source to match the SLAC X-ray pump flashlight re Ne excitation rate.
I'd be delighted if somebody who actually knows about this stuff could set me straight.
What I've read in the media of this process suggests that it's parylene. http://en.wikipedia.org/wiki/Parylene
If so, it's not revolutionary, but a good application of an old coating technology. When I get my iPhone 5, I'll probably send it to these guys for coating.
Feels odd to be living through the prequel to a Vernor Vinge novel....
http://en.wikipedia.org/wiki/A_Deepness_in_the_Sky
If you do, and you haven't discovered Elizabeth George, you have a treat in store. Her stories are intelligent, complex, and engrossing. You can jump in at any point in the series, but as each builds on the prior ones, I really recommend you start with the first, "A Great Deliverance". Have fun on your travels!
Methadone's pharmacokinetics give it a long half-life, and therefore a long duration of action. This is an asset in managing chronic pain from cancer and some other diseases. Methadone has much less tendency to lose its analgesic effect through habituation. Morphine, for example, while an effective pain reliever due to its action on the mu-opioid receptor, has a metabolite that acutally upregulates perception of pain due to action on the NMDA system. This latter effect probably accounts for most of the often-observed dose escalation needed to maintain effective analgesia in patients treated with morphine. The primary danger of methadone is that physicians who are unaware of its comparitively slow pharmacokinetics overdose their patients because they escalate the dose too fast. It is critical to make changes (either increase or decrease) in methadone dosage *slowly* - when that is done, the drug can provide chronic pain relief with a much better combination of safety and long-term effectiveness than many of the other opiates. As always, ignorance seems to be the most deadly disease.
For example - the idea of a time machine has been around for a long time, at least since H.G. Wells wrote about it. If I could *actually* build one....that would absolutely be patentable. It isn't the idea that's patentable, it's how to do it. If, of course, the "how to do it" is novel, useful, and non-obvious.
Ice shell on Europa is thought to be about 100 *km* thick, which would certainly block radio transmissions.
http://en.wikipedia.org/wiki/Europa_(moon)
Interesting you mentioned that. My wife's uncle (in his 80s now) went to Stanford Medical School literally right out of high school on the strength of his grades and a 10 minute interview with the school's Chief of Surgery. He went on to become one of the country's most accomplished chest crackers (thoracic surgeon) and did all manner of good, high-level work in his career. Right out of high school. That could never happen today, although not because the raw material is less talented than in his day.