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30

Off the top of head as a medical professional I can imagine the following mechanisms (everything is just speculative reasoning): Insects don't have blood. Instead, they have hemolymph whose primary role is not oxygen transport (they have an additional tracheal system for this purpose), but rather that of nutrients. Thus they don't need (and don't have) an ...


14

My friend Brightblades is right in one thing. It seems your teacher was working off a caricature of what the theory of evolution actually says. First of all, you should read Sklivvz's excellent answer at this question. Now to address the elephant in the room, the accident at Chernobyl only happened in 1986. That was only 26 years ago. In that timeframe, ...


13

Studies of Deinococcus radiodurans, the most radioactively tolerant microorganism we know, show that it has many genes for DNA repair. In the case of the cockroach, I would assume that in addition to repairing genes, and maybe some antioxidants produced in the cells to quench free radicals produced by radiation, the fact that the roaches lay many, many ...


6

Radiation poisoning causes mutations in DNA that affect normal cell function, often causing them to die. Cells normally have a number of repair mechanisms but if the damage is too great they won't be able to do so. In particular, cells that are dividing quickly will not have time to repair their DNA before division and so die far quicker than other cells. ...


5

No, one can't confirm age by carbon dating. That doesn't mean we can't make a decent guess by other methods. There is an interesting case of a 33 year old Texas woman who enrolled in 10th grade in Texas. She said she had no transcripts because she had been homeschooled. She looked like a teenager and acted like a one too. She even fooled her new 23 year old ...


4

The type of radiation is quite different in a medical X-ray vs. an airport scanner. Medical X-rays are high frequency (beyond ultraviolet) radiation, typically on a wavelength of a few angstroms. While I would emphasize that @Ram is right to point out that there is not very much radiation in a medical X-ray since electronic detectors have been in place ...


4

According to Paul Stamets, Gomphidius glutinosus is especially well suited to collecting Cesium-137: G. glutinosus has been reported to absorb – via the mycelium – and concentrate radioactive Cesium 137 more than 10,000-fold over ambient background levels. That article and Stamets' book Mycelium Running have more details on other species.


3

This is an interesting - and highly debated question. Generally there are two completely different directions of thinking when talking about dangerous substances (this applies to dangerous chemicals as well): The linear no-threshold model (LNT). The hormesis model, in our case the model of radiation hormesis. Summarizing the models the LNT model says ...


3

In the most technical sense, yes. In a practical sense, no. Average background radiation dose from food and water sources is ~.3 mSv according to the UN. Given that it takes 1 full Sv to increase cancer risk by ~5-6%, it seems unlikely that, under normal conditions, variability in consumption of water will change risk in a significant fashion. Now, when ...


3

Great question. It is unfortunate that more people don't understand what "radiation" is and how it affects biology. Firstly, you must distinguish between ionizing radiation and non-ionizing radiation. Wikipedia describes the former rather well: Ionizing (or ionising) radiation is radiation composed of particles that individually carry enough kinetic ...


2

Not sure that I understood your question correctly. The concept of "effective dose" was specially introduced to provide a mechanism for assessing the radiation detriment from partial body irradiations in terms of data derived from whole body irradiations. The effective dose is the mean absorbed dose from a uniform whole-body irradiation that results in the ...


2

It's actually because of the greater risk "from breast, ovarian, and uterine cancers" (article). There's a more scientific write-up here, and while I don't have access the abstract implies that a more rigorous update of the exposure criteria upheld sex differences. From a more terrestrial perspective, The Nuclear Information and Resource Service (nirs.org) ...


2

To grab this opportunity to sum up the comments for the C-14 dating method, including those of of @MattDMo and @canadier: Theoretically spoken - Yes we can! But only after (1) killing the person and (2) waiting a few hundred years. As carbon keeps on being recycled in a living carbon-based organism, it has to be dead first. Secondly, because the margin or ...


2

Xrays are not scans. They are one shot (or a series of a few). Say that a chest Xray (two views) doses you with .1 mSv of radiation. The dose from a standard chest CT is 7 mSv.[1] That is 70 times what a chest film gives you, not a few hundred (though that might seem like quibbling). The TL;DR answer is: no one knows for sure. Radiation (especially in ...


2

As a rule of thumb you can say that a CT scan exposes you to a higher dose than a X-ray examination, due to the different techniques. For CT scans a number of single 2D photos is processed into the 3D models. However, the dose strongly depends on what body part is examined. See a part of this table (the complete table can be found in reference 1): The ...


2

The three major nuclear incidents I can think of are the Japanese atomic bomb attacks, the Chernobyl disaster, and Fukushima disaster. Of course other nuclear incidents have occurred, but usually give much higher doses to far fewer people. Many studies have been done on the survivors from the atomic bomb attacks, and increased rates of cancer have been the ...


2

The original article cited in your reference is available here for free. After a quick skim, I saw that their study was based on fossils of a single species (Moas) all taken within a 5 km radius. Thus, it's possible the fossils were preserved under relatively similar conditions, despite different preservation ages. So, it's not yet clear how their results ...


1

First of all: Technically speaking there is no such thing as a safe dose in radiation like you can say for drugs or toxins. This is because every single event of radiation can cause damage that can cause cancer. Besides that, there is no need to panic about low radiation, since you define certain values which are deemed safe, because the likelihood of ...


1

The principle of targeting cancers with high intensity radiation is already in use. For example: http://www.mayoclinic.org/tests-procedures/gamma-knife-radiosurgery/basics/definition/prc-20014760


1

As per the American Association of Physicists in Medicine the radiation exposure from full body airport scanners is equivalent to what an individual receives every 1.8 minutes on the ground from natural background radiation or equivalent to every 12 seconds during an airplane flight. http://www.aapm.org/pubs/reports/RPT_217.pdf The Back scatter full body ...


1

I haven't been able to find a study on fertility, but it would be important to note the difference between radiation considered. The dangerous radiation discussed in both of your links are cosmic rays as you noted. Our main defense against this sort of radiation is the earth's magnetic field. The hole you are talking about is in the ozone layer, which is ...



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