ZeroZero

Does anyone know about academic work on the role of retroviruses in evolution. I am thinking that these viruses could insert preformed code into alien species and thereby alter their path of evolution. I cant seem to find much material about this in the literature

Can I suggest you actually read the book (and maybe watch the film) before holding judgement. Your comments are way off mark. You need to study more.

I am looking for a site or/and a magazine that would keep me up to date with human evolution. Topics included would be ancient history, anthropology, human behaviour, evolution and biology. I am seeking to avoid all the stupid conspiracy theory stuff - e.g. "proof of ancient technology and space contact" etc... The magazines I have found tend to only cover the topic occasionally Any worthy sites or magazines?

Your explanation is a good one and is accepted. I wonder if there are any perfect shapes at the level of a wave, or perhaps at the level of quarks?

OK, but to the limits of the measurements?

Just wondering what people might say... In nature we never see perfect circles, perfect triangles or perfect polygons such as the Platoic solids? Everytime we see thing that resemble these figures but are in some way flawed, like a crystal for example. I know theoretically we can describe such figures, but why are they not met in the real world? Or are they?

Very average maths here. Rusty on Excel, once fairly competent. I am trying to construct a simple chart in excel Here is the data: Age of the Earth 4.54 (billion years) Archean Era begins 3.8 Proterozoic begins 2.5 Phanerozoic begins 0.57 I am looking to create a sunburst or donut type chart where it shows the eons in segments. 4.54 would be 360 degrees of the chart. I term this whole life of the planet" here "whole" The other numbers would have to be calculated as percentages of the whole I have two questions please: 1] Which formula can you use to express 4.54 as 100% (not as a fraction of 100% but AS 100% or 'all') 2] How would one calculate the other fractions so that the chart has the correct sections? I am stumped! thanks Zero

I have been looking at pie chart type software in Excel. The problem is that the chart 'divides' the pie into parts. That is not what is required, its more like a clock which marks a particulart moment in time. There is also the question of concentric circles - how that is realised in software

I am trying to build a "geological clock" First here is a description of the software device: The device will consist of concentric circles The first or outer circle will represent 14 billion years, on this will be the age of the universe (circa 13.8 billion years) On this circle will be represented the birth of the sun the earth and the moon The next circle will be the "Earth circle" On this will be represented the eons of the earth the Hadean, the Archean, the Proterozoic and the Phanerozoic. The next inner circle would represent the Phanerozoic eon and would be divided the Paleozoic, Mesozoic, and Cenozoic The next inner circle would contain the three periods: the Paleogene, Neogene, and Quaternary; Next would be the Quaternary this would contain the Pleistocene (2.588 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today) |The next inner circle would contain the Holocene and would contain milestones in the development of homo Software? Which software could I use to develop such a tool? If it were intereactive this would be a bonus. I am hoping to be able to click on regions aand bring up associated text If anyone could help I would be grateful thank you all

No Google earth cannot do this.

So, I was thinking about the Lascaux cave and how much I wanted to see it. I know it's locked up but there is a 3 d model somewhere. Then I started thinking that one could share this vision using virtual reality. I confess I don't know much about this subject but simply putting a fixed point 3d map from one single location did not seem enough. Then I started imagining a drone flying through the cave mapping with a camera. As the drone flew through the space, there would be a grid so that it's image would be located into the three dimensional space. As the drone flew more and more, the space with gain further detail. At any given point in time, the drone would 'see' only a few lines of sight, but these would accrue if its flights were randomised. In this way a virtual helmet could locate itself so that it knew where it was and what the images would look like from that perspective I wonder if this sort of immersive algorithms exists for such work? Z

This is my point. If the mitochondria is excluded from the copying mechanism, how is it passed on from parent(s) to child? How does it copy itself 'at the same time as mitosis occurs? Do simply get 'infected' like catching a bug? Z

Can anyone tell me how mitochondria are reproduced and how they engage in cell production? I think I understand that mitochondria have their own SDNA/RNA, how then do they get transferred in sexual and conventional cell reproduction - mitosis and myosis? Do they reproduce in a 'convential' way by compying and replicating RNA? I probably have this all wrong ! thank you Z

thanks for the replies, checking them out Thank you for the replies some were too complicated for my non logical brain, I found this one simple and with a good gui http://www.kolls.net/gatesim/

I am studying Boolean logic gates at present and I was dreaming of having my own circuit board with a few gates to experiment with, then I realised that a laptop should handle the job could anyone recommend a 'virtual circuit board' app where you can attach inputs and outputs of various gates and see the results in terms of 0 and 1's? thank you

here is a site that might interest you. i found it very useful well written and have studied the course http://www.allaboutcircuits.com/vol_4/chpt_7/5.html

http://www.simpledigitalcomputer.com/BuildingSimpleMachines.aspx I am in agreement with this link It's suprising how many answers you can get to this very simple question: http://www.electro-tech-online.com/general-electronics-chat/86128-how-can-i-make-if-gates.html I suppose technically this simple circuit is not a logic gate, I am told that logic gates have at least two inputs. If this is so we must also exclude NOT from the set of logic gates but many people fdo refer to NOT as a logic Gate and the simple switch 'buffer' is the complement of NOT. Protist you stated above "IF statement requires two values". Well yes and no (forgive the pun). An if statement requires only 0 or 1 true or false. This is one value in a circuit its ewither the absence of a current or the presence of one. What I mean is that there is only one input for the decision, not two as in AND, OR, NOR, NAND, XOR. Anyways thats my take on this thanks for the discussion (or should I say input) I suppose I should have said economically without using additional operators In an IF THEN statement there is not a need for two inputs nor does it imply the use of greater than or less than, yes you can add in these operators but they are not part of the IF THEN statement. Maybe think of the question this way - if you were building a circuit and you were interested in using the least amount of parts what would in consist of? Dont mean to be pedantic just interested in getting to the bottom of this. My view is that a simple relay switch is an IF THEN statement, it's often called a 'buffer' in terms of logic gates it's the 'complement' or opposite of a NOT gate. IF (1: true) THEN (1:TRUE). IF (0: not true)NOT THEN (0:FALSE). I am not sure about this though.. Zero ''a

" Yes, because it produces a decision, not a quantity" In Bolean algebra a decision is a quantity. Everything is eith 0 or 1, which can represet FALSE or TRUE when a decision is made it is a switch being set to 0 or 1 The original question: How can an IF THEN statement be made from bolean logic gates? I am starting to think its an OR gate There seems to be different views on this question, from posters

IF (A someone knocks on my door) THEN (B I go and answer it) IF A THEN B Its a long time since i programmed but in the sense above I cannot see what are 'the two values to compare'.

I think I have figured this one out. It is a logic gate but a rare one called a 'buffer'. This is a simple gate with one input and one output. If the input is 1 then the output is 1. If the input is 0 then the output is 0. This may seem a bit pointless for a logic gate and indeed it is a rare item. Its the opposite of a NOT gate. Of course the first 1 may represent anything - say fish, the second 1 may also represent anything, say fishing. IF fish THEN Fishing Input fish, output fishing The AND gate has two inputs therefore cannot be an if then statement.

This question has just occureed to me and i find it interesting. Assuming a person is blind from birth, how do they understand sight in their own mind. I know a superficial answer is easy to ascribe, but looking a little deeper, are there any common mistakes that a blind person might make, are there forms of cognition (not perception but cognition) that consequently become unavailable. I know for example that a pianist has a certain advantage as they can only locate the keys without the use of sight, where a sighted player (and I am one) can only seem to look at one hand or the other. If the habit of finding a finger position in one hand is triggered by vision then if you look at the other hand this trigger is lost - unless one develops panoramic vision of both hands simultaneously. Is quantity harder to understand for example in developemet of the brain? Are blind people better or worse at math? Is the notion of perspective difficult to grasp? We use this term psychologically as well as practically 'metaphorically if you like? Obviously non verbal expressions would be unavailable, does this impair emotional development. It seems to me not so, but then why not so? I googled this but there seems ot be little discssion. It would be interesting to see a birth-blind person being interviewed regarding their opinion on sight Anyoe care to comment?

Hi all, I am just revising my computer skills after a 30 year break. The question on my mind is what are the fundamentals building blocks of computing? From my revision I have learnt that there are four basic logic gates AND OR XOR and NOT - from these all other logic gates can be built. Then of course there is binary. the conditional statement IF - THEN is currently puzzling me how is this constructed from the above operations? It seems to me that it cannot be?

Thanks for your help all. I think I get this now. All right angled triangles of the form 45,45, 90 degrees have irrational numbers as the hypotonuse. Others don't - necessesarily (though some may have). many thanks

Yes I made two schoholboy mistakes. 1] 12*12 + 12+12 = 288 not 388 2] I used a caculator to get the square root of 288 not a good move I think so the square root of 288 is an irrational number too? If i were to use other arbitrary measures to divide the lengths would I also get irrational numbers? Are all answers to the pythagorean calculation of the length of the hypotonuse irrational (expect perhaps when the opposite and adjacent are irrational - now there is an interesting question) I dont know how to indentify an irrational number except to say it is not a product of an integer fraction - including re-occurring such as 1/3

So 12 X 12 is an irrational number? And yes 12 inches =1 foot the triangles are identical in all respects not merely congruent. The only variation is the arbitrary definition of measurement units. This would imply that we only get irrational numbers if we use certain arbitrary divisions working in metres would produce different results from imperial.