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31

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

Addition to the previous answer First you need to understand how radiation causes cellular damage. EM waves like γ-rays, X-rays and high-energy UV (in certain molecules even visible light) can knock out the electrons from the atom and create an ion and free radicals by breaking chemical bonds. This term — ionizing radiation is not used for low energy UV ...


4

Yes, this can happen, although the risk is low. The problem is that some tumors need to be irradiated since the cannot be operated (this is true for some brain tumors). Here the radiation therapy is the therapy of choice. The effect of the therapy is that the tumor cells get a high radiation dose which either kills them or drives them into apoptosis. The ...


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

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 ...


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 ...


2

Is background radiation a critical component of evolution? No, it most certainly is not. The DNA replication and DNA repair mechanisms aren't perfect and errors happen without any external cause or catalyst. You could say mutations happen on their own. There are mutagens that also cause DNA damage or mutations, but they're merely affecting the DNA ...


2

Afaik. radio waves don't have enough energy to cause anything similar to the damage ionizing radiation (gamma rays) does. What it can cause is probably heat damage similar to microwave ovens. According to the United States Food and Drug Administration's Center for Devices and Radiological Health, a U.S. Federal Standard limits the amount of microwaves ...


2

How far could we go towards engineering a space-durable human species? I think this question is likely to get closed as off-topic. It is extremely hypothetical and would be a better fit on WorldBuilding.SE. But here is my messy attempt to answer this question. Assumptions So, I guess in your question, you assume that we know everything about how our ...


2

In order to date the age of a tree, you have three solutions : If you can cut the tree then you can simply count the number of rings. Note that for very old trees the central rings will have rotted and you will only have a lower bound on its age. If some parts of the tree are dead, you can use radiocarbon dating to estimate the time of death with a ...


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

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 ...


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 ...


1

If the question is related to exposure to radiation in a Nuclear submarine then the answer is valid for radiation exposure irrespective of the place. As you are aware there are many effects of radiation. Some of them are. Nausea and vomiting Diarrhea Skin burns (skin reddening) Weakness Lethargy and fatigue Loss of appetite (anorexia) ...


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

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

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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