Jeffrey Bada at the Scripps Institute is finding more interesting stuff in Stanley Miller’s spark-discharge tubes – with a little tweaking of ingredients. Scientific American acknowledges that the famous experiment fell into disrepute when scientists used a more realistic atmosphere: “It seemed to refute a long-cherished icon of evolution—and creationists quickly seized on it as supposed evidence of evolution’s wobbly foundations” (see also Robert Shapiro’s critique in the 02/15/2007 entry, “the soup kettle is empty”). This realization caused many in origin-of-life research to postulate that the building blocks of life came special delivery, from comets and meteors. Bada decided to try a variation. He neutralized the acids and removed the nitrites that interfere with amino acid formation, and got amino acids to form in abundance. He rationalized this by saying that iron and carbonates on the early earth would have neutralized the primordial soup in a similar way. Other researchers were buoyed by this finding. They think it will tip the paradigm back toward local formation of amino acids on the Earth, through lightning and radiation. Others caution that not all the building blocks can be formed in this manner; special delivery may still be required.Same problems: mixed handedness, no concentrating mechanism, no peptide bond formation mechanism, no nucleic acids or sugars, competing reactions, investigator interference, the fallacy of using the intelligent design of the scientist to emulate chance and necessity, etc. Check our extensive reporting on origin-of-life research and debates by following the “origin of life” chain links going back over six years. Interesting that they called this an icon of evolution. Jonathan Wells had a whole chapter about the Miller experiment in his book of that name. They also are painfully aware that creationists have had a field day with the refutation of the Miller icon. On the ropes since the heady days of the 1950s, the OOL research community thinks there may be life in the useful lie yet (05/02/2003). Not likely. Creationists not only seized this wobbly player in Darwin’s wrestling match; they have him in a chokehold on the floor. He will need a lot more nutrition than a few random amino acids to get up again.(Visited 27 times, 1 visits today)FacebookTwitterPinterestSave分享0
UV radiation quickly degrades amino acids on most Martian minerals, a new study shows.Using the “Open University Mars Chamber” in the UK, four British scientists watched to see what happened when amino acids were subjected to ultraviolet (UV) light. They spiked 11 different minerals known to exist on Mars with different concentrations of amino acids, then irradiated the rocks with UV ray levels expected at local noon for a total of 28 hours of exposure, the equivalent of about 6.5 Martian days’ worth of UV dosage. They published their results in an open-access paper on Icarus. Here are the highlights:D- and L-amino acids were degraded equally under simulated Mars conditions.Smectites and sulfates preserved the highest amino acid proportions from degration [sic].Sulfates protect amino acids likely due to their opacity to UV radiation.Minerals containing ferrous iron promote the destruction of amino acids.Finding #1 reinforces the idea that L-amino acids (left-handed) are thermodynamically equal to D-amino acids (right-handed); i.e., nothing in the environment would favor their survival. Life on Earth uses only L-amino acids. Without a mechanism to favor one over the other (produce an “enantiomeric excess”), there is no known cause other than chance to incorporate all one-handed amino acids in a protein (see online book).Although some of the minerals preserved amino acids, Finding #4 shows that ferrous iron (II), which is common in basaltic lava, promotes their destruction. Of those minerals that did preserve them, the initial “spiking” abundances were higher than considered plausible. This sentence in the paper could be easily missed: “The abundances used in this manuscript are higher than what it is expected to be present on Mars, placing a limit of detection for the preservation of amino acids under Mars conditions.” If they had started with the most optimistic but realistic abundances, would any amino acids have remained?Mars, not having a global magnetic field, has no natural shielding from solar UV rays. Even if one could hope for some amino acids to survive the daily barrage of UV radiation, there are other discouragements for astrobiologists. The authors lay this one out in the final paragraph of the Discussion section:As a final note, UV irradiation on Mars is limited to the first millimeters, but energetic particles (solar energetic particles (SEP) and galactic cosmic rays (GCR)) can go deeper in the subsurface, reach organic molecules and contribute to their degradation. A SEP dose of 600–700 mGy/yr can reach the surface of Mars and penetrate to around 10 cm, while GCR are typically capable of penetrating up to 3 m into the subsurface (Parnell et al., 2007) and over geological time, deactivate spores and degrade organic species (Dartnell et al., 2007). Therefore, future work should study the influence of the minerals on the preservation of organic molecules under simulated Mars conditions using SEP and GCR.Since SEP and GCR penetrate far deeper than the UV studied in the Mars Chamber, they would clearly predominate. The experiments in the Mars Chamber excluded the very radiation that would likely overpower any protection from UV afforded by the minerals tested. Armor that can deflect BBs may be ineffective against machine guns. In the Introduction, the authors had said,Two of the factors contributing to the harsh current martian environmental conditions are the thin atmosphere and the absence of a significant magnetosphere (Fairén et al., 2010), resulting in the inability to attenuate the intensity of the multiple forms of solar radiation that reach the planet, such as UV radiation, galactic cosmic rays and solar energetic particles (Cockell et al., 2000 and Hassler et al., 2014). As a result, the martian regolith is exposed to intense levels of radiation, contributing to the reactivity of the soil which may destroy potential martian life and degrade organic molecules ( Dartnell et al., 2007 and Quinn et al., 2013).The paper, therefore, has little bearing on the actual preservation of “building blocks of life” on the red planet. Unless astrobiologists seriously want to consider life evolving deep under the surface, Mars appears to have a 10-foot-deep dead zone where the combined radiation from solar and cosmic would easily destroy amino acids, nucleotides and other biological ingredients over years, decades and centuries of exposure. How, then, would any deep-down emergent life ever survive a rise up to the surface where it could be detected? Even its basic molecules would be burned to a crisp in due time.Remember that Mars is the most likely place where astrobiologists think life could survive beyond the Earth. “The detection of organic molecules associated with extra-terrestrial life has been primarily focused on Mars due to its proximity to Earth, evidences of a congenial past environment and potential to support microbial life,” the paper begins. Anybody see potential there now that the results are in? Get real. Our moon is in the sun’s habitable zone, and look at it. Without planetary protection from the right atmosphere and a global magnetic shield, it’s not going to be habitable except for intelligent humans for short periods in intelligently-designed spacesuits that carry a simulated Earth environment with them. (Visited 164 times, 1 visits today)FacebookTwitterPinterestSave分享0
FURTHER RESOURCES:In Green Basics: Blown-In or Loose-Fill Insulation Insulating Roofs, Walls, and FloorsIn Product Guide: Blown InsulationIn Community Forum: Dense-packed insulation Is dense-packed cellulose an air barrier?In Blogs: Cellulose Insulation Roofing and Siding Jobs Are Energy Retrofit OpportunitiesVideos: How to Install Rigid Foam Insulation Outside a House Superinsulating a Home With Rigid Foam Editor’s introduction: With energy prices rising again, many homeowners are planning energy-efficiency improvements to their homes. But most people are unsure of where to begin, and even seasoned builders don’t always know which priorities should rise to the top of the list. Betsy Pettit, an architect at Building Science Corporation , recommends starting where you can get the most bang for the buck.Step 3: Insulate your wallsTable of Contents:1. The Basement2. The Roof3. The Walls4. The Windows5. Mechanicals6. Appliances7. Renewable EnergyFilling empty wall cavities with cellulose is a cheap, easy, effective way to warm up an old house. Blowing insulation into existing wall cavities is an art, to be sure, but many contractors have been doing it for years. By checking the quality of the job with an infrared camera, an insulation contractor can verify that all voids have been filled.If the home’s existing siding is nearing the end of its useful life, it’s possible to install a thick layer of rigid foam on top of the existing sheathing at the same time that the siding is replaced.This article is adapted from Betsy Pettit’s Remodeling for Energy Efficiency in Fine Homebuilding magazine.
The ruling Communist Party of India (Marxist) in Tripura has urged the Election Commission to hold the Assembly elections in early February. The party made the demand in a memorandum placed before Deputy Election Commissioner Sudeep Jain, who was leading a four-member team to the State to oversee poll preparations.The main Opposition, the Bharatiya Janata Party, in its submission to the team, did not press for a specific time for elections but requested the Commission to ensure an extensive revision of the electoral rolls to delete bogus voters. The term of the present Assembly will expire in February next.
The West Bengal Cabinet on Wednesday decided to draw up a ‘Vision 10 and Vision 20’ plan for better performance and development in various fields in the next 10 to 20 years, Chief Minister Mamata Banerjee said.“We will plan for 10 years and 20 years because if there is no proper planning, then there will be situations like the recent collapse of bridges. The Finance Department with the help of the Statistics and Planning Department will work on this,” she added.
ShareEXPERT ALERTDavid Ruth713firstname.lastname@example.org Rice U. expert available to discuss Paris ‘terrorist act’ HOUSTON – (Jan. 7, 2015) – Rice University political scientist Richard Stoll is available to comment on the apparent terrorist attack on the offices of French magazine Charlie Hebdo in which 12 people have been reported dead. FacebookTwitterPrintEmailAddThis Richard Stoll photo courtesy Rice UniversityStoll, the Albert Thomas Chair in Political Science and scholar at Rice’s Baker Institute for Public Policy, said, “Although we know few details, the history of Charlie Hebdo certainly suggests that this was done in retaliation for their satire. “This was a particularly bold act, but the videos of it should facilitate French authorities with tracking down the perpetrators.”Stoll has been quoted often by the news media about national and international security issues. Media wishing to interview Stoll should contact David Ruth, director of national media relations at Rice, at email@example.com or 713-348-6327.Rice University has a VideoLink ReadyCam TV interview studio. ReadyCam is capable of transmitting broadcast-quality standard-definition and high-definition video directly to all news media organizations around the world 24/7.Watch Stoll on KRIV-TV, Fox 26 Houston, discussing the attack on Jan. 7. Follow Rice News and Media Relations on Twitter @RiceUNews.Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,920 undergraduates and 2,567 graduate students, Rice’s undergraduate student-to-faculty ratio is just over 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is highly ranked for best quality of life by the Princeton Review and for best value among private universities by Kiplinger’s Personal Finance. To read “What they’re saying about Rice,” go here.