Arthur Smith

Well, I guess a histogram would do it. Start with a graph of horizontal scale 100 km and rectangles of one millimetre. Height of each will be proportional to the fuel used over the distance interval. Play with scales and you have a representation of fuel consumption over distance as the area under a line following the height of the rectangles. Why do I feel I'm differentiating? 

2 hours ago, md65536 said:

What is the cross section of a pipe filled with fuel, that you consume by moving along it instead of moving the fuel through the pipe?

Sorry, didn't spot these replies as I just noticed a reply flagged on activity and it took me straight to exchemist's comment. 

I'm guessing "what" is a typo for "that", and I agree.

1 hour ago, Sensei said:

Why use such an arbitrarily large unit as millimeters? You can use nanometers, picometers, or even better, calculate how far a device will travel per molecule of fuel..

 

Is there a limit? Are we in Zeno's paradox?

1 hour ago, John Cuthber said:

Which sort of molecule?

The european molecule 😉

As I feared, the question is trivial. If you wanted to establish instantaneous consumption, you could simply reduce the distance of travel from one millimetre (which consumes 0.05 cubic millimetres of fuel) to zero. Which is not possible.

Though I guess you could model instantaneous fuel consumption by keeping flow to the engine constant and reporting the required cross section of supply pipe. Foot off, downhill and cross-section is zero. 

Hi folks. I've not posted in a while but thought of this site when a topic cropped up elsewhere. Apologies if it has already cropped up here but I didn't find anything with a quick search.

It is standard in Europe to quote fuel consumption for a liquid-hydrocarbon-powered vehicle in volume of fuel burnt per distance covered. A small car may achieve 5 litres per 100 kilometres, for example.

But if we convert both volume and distance to the same unit, millimetres, we get 5,000,000 cubic millilitres over 100,000,000 millimetres. This gives us an area of 0.05 square millimetres.

With me so far? 

4 minutes ago, exchemist said:

In that case I should look out for them. I don't drink much champagne, though I keep handy a few bottles of Deutz, which we don't see much in the UK but was introduced to me by my late wife's Oncle Philippe.

In fact, on checking, see the Wine Soc currently has Antech Crémant de Limoux , Héritage 2018 going for £17/bbl. That's a lot cheaper than champagne, certainly. (And also a Blanquette de Limoux but that is semi-sweet so I'll give it a miss.) 

Antech has an excellent reputation for quality. Can speak first-hand! 😇

4 minutes ago, exchemist said:

Aha. This is in Languedoc, I see. Interesting. Are these wines made by the méthode champenoise?

Yes. Some smaller producers still use pupitres and hand-turning though most larger coops have automized.

On checking, I see Champagne has also adopted machine remuage.

2 hours ago, Sunila Jha said:

Hi All,

I wanted to do a Data Science Course but, i don't have any prior knowledge in programming. 

One of my friend told me to learn Java and Python (i have started learning python on Scaler Topics).

My questions is, is there any other programming language i should learn?

 

Fortran was good enough for me. I see it's still going.

6 minutes ago, exchemist said:

I meant leaving half of an opened bottle, not a glass, in the fridge. It's still good 24hrs later, although the fizz has subsided to more of a crémant. But still perfectly pleasant

I live in an area that produces carbonated wine, not champagne, Limoux.  Most people seem to possess a clip-on seal that retains the fizz in open, fridge-stored bottles for a few days. We also make Blanquette de Limoux, Méthode Ancestrale, which is only 6%. Not sure if it is available elsewhere but very refreshing on a hot day.

The greased piglet may yet escape, for now.

22 minutes ago, exchemist said:

...fizz has subsided to more of a crémant.

Another shameless plug for Limoux wines. There are three appellations, Ancestrale mentioned, Blanquette de Limoux (major grape variety, Mauzac, not high in acidity) and Crémant de Limoux, which can have up to 60% Chardonnay (the workhorse Champagne grape) so worth considering as an alternative to Champagne.

One data point is what we have. I suspect one data point is all we will ever have.

23 minutes ago, Peterkin said:

It does mean both earthly and land-dwelling. I don't see the application to this thread, or to my quoted comment.

Yes and I intended in the "not from Earth" sense. In context, I thought it was obvious but someone misunderstood. That it why I took the precaution in clarifying above. Again, this is an open forum.

7 hours ago, Peterkin said:

The specific named characters, no. The circumstances* and conditions prevailing in the period, yes. Roman colonial history is quite well documented. I have never claimed  more than conjecture based on available circumstantial* and historical evidence, most of which I cited. 

* yes, I do know what 'disinterested' means, and I'm also aware of  how large a part circumstantial evidence (I know what that means, too) plays in historical reconstruction, scientific theory and criminal prosecution.  

Nobody's asking you to believe Christian lore.

Previously someone took my use of "terrestrial" to mean "land-based (non-aquatic)" rather than "(from the planet) Earth" and I didn't get chance to clarify before that thread closed. And I note there are contributors who may not have English as a first language. The clarification was not intended for any particular commenter.

1 hour ago, beecee said:

My point is that much of this so called history is obscure...

Circular would be nearer the mark. There's very little evidence of any Biblical characters or events for disinterested* historians to research. Ditto for archaeologists. The archaeology of the Levant has been subject to political control since it became a genuine discipline which has added to the problem of independent verification of people and events described in the NT.

*Disinterested means impartial, objective.

5 hours ago, studiot said:

 

I don't know where you are in the world, but it is available free on the BBC iplayer.

France. Up until recently I could easily access iplayer via VPN but no longer, it's almost impossible now. I was thinking of renewing my Prime account anyway so may do that.

5 minutes ago, StringJunky said:

Here's a compact discussion: https://microbiologysociety.org/blog/why-dont-archaea-cause-disease.html

Thanks,that's helpful. Suggests that archaea are being overlooked less than previously. From an evolutionary point of view, an organism with no volition (caveat on motile bacteria and Archaea) can't help but profit from an opportunity presented. Whilst Archaea are an ancient kingdom,  they have stumbled (or the motile ones tumbled) upon recent opportunities such as the gut of humans.

A recent study on Koreans. I'm frankly staggered at the abundance and variety. Opportunity for symbiont, parasite and pathogen.

12 minutes ago, Genady said:

While there are so many detrimental bacteria, there are no detrimental archaea. Is it so? Why? 

That's an intriguing question. I can see there is a pile of stuff with the consensus that while some archaea can be find in our gut, there is no unequivocal case of an archaean pathogen. Though I see some have alleged they may play a rôle in some diseases, the list includes Crohn's disease, arthritis, lupus and gingivitis. Certainly seems that Archaea are for the most part benign organisms. I have no immediate suggestion as to why. Will read some of the articles I've turned up.

5 minutes ago, Genady said:

Sure. But this scenario cancels the other consideration, "No knowing where we could end up in a billion years or so."

Sure. I was only being serious about the inevitability of climate change and the problems humankind are already facing that will only get worse. I suspect this is getting a little off-topic for the search for extraterrestrial life.

4 minutes ago, Genady said:

On the other hand, if we all go extinct here on Earth, then 4 billion years of evolution will go down the drain.

Well, climate change will be bad enough that humans could become extinct but that will leave the field open for other species to fill the gap and evolve in all sorts of ways we can't predict.

1 minute ago, mistermack said:

I feel that way now. Every time another species goes extinct. I know extinction is a natural process, but what we are living through and causing is not natural, it's catastrophic. 

Ninja'd 

Duplicate

20 minutes ago, Genady said:

When we find a promising but sterile world, shouldn't we throw some archaea there with a purpose to spread life?

Good grief, no! No knowing where we could end up in a billion years or so. ETA In fact that could be us, the seeded archaea (with a sprinkling of bacteria) and our benign overlords watching developments until we are ready to be contacted I jest but Kipping is making his point using a timescale from abiogenesis to intelligence of a couple of billion years. I think the point that some sort of life (leaving stromatolites as evidence) of life starting very soon after water condenses on Earth is an argument for the inevitability of some sort of life arising, given the right environment. That second data point would be quite useful.

13 minutes ago, Genady said:

After 25 minutes he comes to the conclusion, "We don't know." Should I try the second video?

David Kipping (the astronomer in the videos) has published a paper on this:

https://arxiv.org/pdf/1806.08033.pdf

I managed to watch the second video. Having the paper available helps with following the video.

In his concluding remarks, he seems to agree a second data point would be handy. Actually the video was also good for improving my understanding of Bayesian analysis. So thanks, mistermack!

34 minutes ago, mistermack said:

The problem of only having the Earth to go by, a single datapoint, is adressed by this guy on youtube, and although I'm a non-mathematician, I think he presents it clearly and well from a mathematical angle, and he claims that you can use maths to get to a real probability result about the existence of life, and the existence of intelligent life.    Well, I liked it enough to watch both, so here are the links, in case you might too :  

https://www.youtube.com/watch?v=PqEmYU8Y_rI  and       https://www.youtube.com/watch?v=iLbbpRYRW5Y   

And apologies if someone has already mentioned them. 

 

 

Thanks for providing links. Unfortunately, my internet speed is 0.5Mb currently, I'm promised fibre later in the year (already behind schedule due to Covid) so at the moment  I can't watch Youtube. ETA I managed via hotspot on my cellphone.

On 12/9/2021 at 12:24 PM, swansont said:

We have one data point for life getting started on a planet with liquid water, and there is life. How does one extrapolate that to get a level of difficulty?

Indeed, until we get a second data point, we are limited to informed speculation. I was going to enlarge but here is a blog post I came across elsewhere that makes some good points. It is talking about the current effort to recover physical samples from Mars.

Also Robert Shapiro wrote Planetary Dreams in 1999 advocating exploration of space to search for life elsewhere. Shapiro is best known, unfairly I think, as a critic of the RNA world hypothesis and he does touch on that in a chapter "Birth of the RNA World". The approach is more "needs more work" than "nonsense" and a lot of work has been done since 1999.

On 12/9/2021 at 7:37 PM, studiot said:

I am trying not to spoil the series for those who might wish to watch as it was really quite good and explored many issues in a way that only SF can.
Some ideas were drawn from 'A space oddesy' - but were , in my opinion, much better done.

I missed that as I don't subscribe to OCS. I see it's available on Amazon Prime now. Thanks for the info. I'll give it a go.

What about chemical kinetics? Not sure what you want to know.

19 hours ago, studiot said:

I am observing that a particular sequence of chemical events brought about Life, but there could be other ones or other occurrences of the same sequence.

Chemical kinetics is based on statistics and a proper statistical analysis of these various alternatives would bring greater insight.

There isn't a question there.

(Horizontal line)

@studiot

And my comment about chirality was in response to your question about Japp's theory of chirality, for which I haven't been able to find a clear statement. I'd still like to establish what that is, if only to draw a line under it.

Shapiro's book is very much in line with the thread topic and wasn't directed at you particularly. Forum software insists on merging replies which is why I've been adding horizontal lines.

5 hours ago, Arete said:

...viruses do not necessarily share a common ancestor with prokaryotes/eukaryotes/archaea.

Is that a throwaway remark or are you suggesting virus origins are separate from all other terrestrial life?

https://www.nature.com/scitable/topicpage/the-origins-of-viruses-14398218/#:~:text=Viruses may have arisen from,the evolution of%2C cellular life.

For background.

41 minutes ago, CharonY said:

Sorry, I think my comment might have been a bit cryptic. I just meant to say that viral evolution or the development of mobile genetic elements in general are what has been discussed under the catchy umbrella of "Selfish genes" i.e. genetic elements that propagate without conferring selective benefits to their host (or being detrimental to them). Which is a bit of a different line than thinking of virus as reduced organisms (I think that line of thought was mostly fueled by the discovery of "giant" viruses).

No problem. I realised after my wading I'd read more into your comment than you intended. On the other hand, your suggesting an HGT involvement in virus evolution is intriguing.

43 minutes ago, CharonY said:

One line of thought assumes that they developed from mobile genetic elements (think transposons, plasmids, integrons and so on), which incidentally fits the original thread (Selfish gne) quite well.

I keep making the excuse that I'm new here. Haven't read that thread. A link to  the relevant comment(s) would be greatly appreciated if not too much trouble.

Never mind, I found it. I see it dates from 2004 and Dawkins' Selfish Gene crops up in the early comments. I'll wade backwards.

-----------------------------------------------------------------------------------------------------------------------------------------------------------

Hmm. wading through a lot of oyster guts but no pearls so far.

3 hours ago, Arete said:

Virus genomes can be dsDNA, ssDNA, dsRNA or ssRNA. They can also be linear, circular, segmented or continuous. 

TIL

Archaea have their own double-strand DNA viruses.

https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008574