Forgot your password?
typodupeerror

Comment: If your research is covered, this is very helpful. (Score 2) 119

by Penicillus (#36338290) Attached to: National Academies Release Over 4,000 Free Science Books
Very often, the books and papers from NAS, NAE, IOM and NRC provide excellent references by the best people in the country and are very good evaluations of current research, and how we got there. In my work in indoor air quality microbiology, I downloaded one of their books (a page at a time), and the references and reviews were exceptionally helpful in my keeping current and interpreting data. Making their work available for downloading in large units is awesome!

Comment: The increase in resolution is about 4X (Score 1) 163

by Penicillus (#35365630) Attached to: World's Most Powerful Optical Microscope
This increase in resolution to ~50 nanometers is about 4X better than the ~200 nanometers (0.2 micrometers) that (because of diffraction) is the absolute best one can obtain with normal, visible light microscopy, assuming one uses oil and apochromatic objectives. For reference, we used to use the diatom, Amphipleura pellucida, which had 40 striae (lines of holes) in 10 micrometers. If we could see the striae (0.25 micrometers apart), we knew we had an excellent objective. If we could count the striae, we were estatic.

Comment: Re:Comments funny, Dengue serious (Score 2) 140

by Penicillus (#35040478) Attached to: Malaysia Releases Genetically Modified Mosquitoes
This is a good thing. I am a returned Peace Corps Volunteer from Malaysia. While I was there, several of us went camping in the Taman Negara (the rainforest that is located along the spine of the Malay peninsula), and one of us became ill with Dengue fever. We had a difficult time bringing him out. He developed a high fever, was very sick and was hospitalized - fortunately he mad a complete recovery. This is a pilot project, and I wish the Malaysians well. If the project works, economically, environmentally and otherwise, and more genetically modified mosquitoes are released, Malaysia could benefit considerably.

Comment: Access to Tools (Score 1) 393

by Penicillus (#33185528) Attached to: Forget University — Use the Web For Education, Says Gates
Something that hasn't been mentioned is access to tools. Brick and mortar universities have SEM and TEM microscopes, near state of the art computers, instruments, laboratories, etc. that most internet students can't access. Universities have access to databases of current journals, which are very expensive. Also, the universities have individuals (professors and fellow grad students) who have experience using those tools (how and when to calibrate them, how they can be used, etc.) that one learns over a second pitcher of beer. Access to information over the internet is so much better than it was even 10 years ago, but one still needs hands-on experience with the tools, which are first available at brick and mortar Universities, and possibly (if one is fortunate) later in industry. Bill Gates had, for his day, access a very good computer tool, and he used it to begin to get where he wanted to go.

Comment: xrf and lead-based paint -a correction (Score 1) 206

by Penicillus (#32465874) Attached to: McDonald's, Cadmium, and Thermo Electron Niton Guns
Correction - the paint on homes is considered lead based paint if the house was built earlier than 1978. FWIW, lead based paint is considered 0.5% Pb or greater by weight and any paint with lesser quantities of lead is considered lead-containing paint. HUD housing regulations for lead paint kick in when children 0-6 are present, and OSHA considers any lead in paint to be covered by the lead exposure standard.

Comment: Re:XRF is not a replacment for labratory testing. (Score 4, Informative) 206

by Penicillus (#32465814) Attached to: McDonald's, Cadmium, and Thermo Electron Niton Guns

I sometimes use it to analyze soil samples in the field. Since you aren't necessarily shooting a homogeneous substance, you sometimes get results that don't reflect the overall concentration. To get meaningful data you have to send it to a fixed lab where they will extract it and get an analytical result that is more likely to reflect the real concentration.

Actually, XRFs are commonly used by industrial hygienists to determine concentrations of lead (Pb) in lead paint. In fact, the new renovation, repair and paint (RRP) law that went into effect on April 22 assumes lead is in paint on homes built before 1981, unless the paint is measured to be less than 0.5% lead. The best way to do so (per EPA) is to use an XRF to determine whether lead is present or not, and what its concentration is. Alternatively, paint chips can be analyzed for lead in a laboratory; however, one can obtain 200-300 measurements for lead in a building with an XRF, whereas one may take 10-20 paint chip samples in the same time. What I'm guessing happened is than an IH used an XRF on a glass that his/her kid brought home from McDonalds and found some aberrant spectra - the IH took those readings further, and found the spectra matched cadmium. He/She then sent the glass with the readings to the Congresswoman. Given that cadmium has been substituted for lead in kid's toys, etc. (which was prohibited by law), and cadmium is considerably more toxic than lead, the Congresswoman had the glass tested, and the recall began.

Comment: Re:By what definition of species? (Score 1) 256

by Penicillus (#32435530) Attached to: New Estimate Suggests 5.5M Species On Earth, Not 30-100M
Hey guys, biologists will tell you that a "species is what a taxonomist (person who studies it) says it is" There are folks who believe in "biological species - species separated because they can't interbreed (mostly zoologists), folks who believe in "morphological species" (often botanists - people who say a species is a species because it is visually distinct), folks who separate species because they are on separate land masses (Chinese and American Sycamores), chemically distinct species (some fruit fly species separated by scent), behaviorally distinct species (crayfishes), etc. The list goes on ---

Comment: Re:Water is a scarce resource (Score 1) 139

by Penicillus (#30388330) Attached to: Self-Destructing Bacteria Create Better Biofuels
Actually, using cyanobacteria can get around the scarce resource problem, because cyanobacteria are among the most efficient micro-organisms at growing in hypersaline, warm ocean (and salt flat) environments. In freshwater pond environments, one sees a progression of algae from diatoms (early in the growing season when the water's cold) to green algae, to cyanobacteria. Many researchers attribute this progression to the microcrustaceans' eating preferences, literally spitting out the cyanobacteria until everything else is eaten.

Computers are unreliable, but humans are even more unreliable. Any system which depends on human reliability is unreliable. -- Gilb

Working...