studiot

Questionposter, You may wish to know that other (recent) Nobel Laureates in Physics have views closer to your own. Here is a quote from "The Lightness of Being" by Frank Wilczek In this book, Wilczek discusses the role of modern QM in the scheme of things, what it achieves and does not achieve. Nowhere does he state explicitly or imply that duality has been superceeded. Rather he interprets WM as providing probabilities of observing a particular particle or particle property.

Good morning, John. Why am I and the public at large not reassured by your responses? Perhaps because the public is reeling from example after example of scandal after scandal promulgated by some form of big business. This is not confined to farming but extends across the whole gamut of business activity. Asbestos, Tobacco, Three Mile Island, Bopal, BP Oil, Achill Lauro, financial scandals the list goes on and on. So perhaps I should add another benefit to organic farming. It highlights malpractice and offers alternatives. Incidentally for those wedded to calling organic farming medieval I would observe that the first successful modern (=western) system of intensive farming was the introduction of crop rotation - a thoroughly organic practice.

I am glad that missippichem has introduced a much needed dose of levity to the thread. Thank you. Yes indeed. I acknowledged this in my opening post by stating that I considered the responses to (1) & (2) unbalanced. So I stated my intention to redress that balance. I do not believe that the OP really meant (2) as written. "whether these solutions really work" By definition if it is a solution it works! Might techniques be a better word than solutions? The whole question sounds like preparation for a 'compare and contrast essay' Once again balance is needed to achieve this. So Do organic techniques work? Yes Do they have drawbacks or disbenefits? Yes, Lower yields per acre (though not always) as compared to intensive farming is one. Set against this intensive farming methods in the past has caused some spectacular failures and destruction of huge areas as useful agricultural land. the Texas Dust Bowl in modern times and the North African Sahara fringe in Roman times are examples. Increased reliance on labour. This is arguable factor in these days of very high unemployment, since many workers have lost their jobs to increased mechanisation 'efficiency'. Are they the same as medieval techniqes (as suggested) No, they allow mechanisation in working the land harvesting, processing and storing the produce. What is the Soil Association mark? Many (if not all) modern chemical farming techniques lead to excessive residues of chemicals in the soil. Farmers in the Uk are not infrequently prosecuted for allowing nitrates to pollute the water supply. To be a Soil Association certified organic producer in the UK you have to have your soil independent tested and verified free of these chemical residues, both pesticides and fertilisers.

You are off topic sir! The question (I repeat) was clearly stated in the thread heading. "What problems does organic agriculture solve?" My reply is simply Organic agriculture would have prevented prion contamination. I could have said Organic agriculture would have prevented gender differentiation issues observed in Italian children fed on milk containing excess hormones or Organic agriculture prevents gender differentiation issues in some fisheries or Organic agriculture disallows the selling on infertile seeds (especially seed potatoes) to prevent farmers gathering and reusing their own. or Perhaps the OP should ask a few farmers about the 'deals' pressed upon them by some big chemical companies. Yes, technology has benefitted mankind but excessive pursuit of the profit motive has also worked to his detriment. Equally blind adherence to established ways and ludditism has also brought hardship.

I'm sorry but I found the replies exceeding biased. Particularly as they did not answer the question as I have already pointed out but instead rubbished organic methods. Here are a few sample quotes. Here is a more rational response, which I will answer. missippichem from your name I guess you are in the US which has long generated a significantly larger beef production than the UK, the country to which I referred in this instance. Intensive farming allowed a greater cattle population per acre than the land itself would sustain, with additional food being supplied from elsewhere. Cattle are herbivores but were fed on diet increasingly including animal 'residue'. Two effects flowed from this. Firstly BSE took hold in some of the cattle population. Secondly a variation of the disease spread to some humans associated with these cattle who then died a horrible death. No organic beef cattle contracted BSE and no workers on organic farms contracted CJD. Eventually the UK government had to slaughter and burn the carcasses of pretty well every beef cow in Britain and import clean replacement yearlings. All were slaughtered, whether they had the disease or not. That included the cows from blameless organic farms who did not practice this method of feeding. The taxpayer also had to compensate the owners of all these cows, many farmers nevertheless went bust. The export and home sale of UK beef was banned for several years. Finally new regulations were introducted outlawing these feeds. In the USA and Argentina where they have large wide open ranges and relatively natural feeding regimes they did not experience this problem. Now I don't fully support organic methods since they include disallowing modern vetinary treatment (drugs) of sick animals. Edit Let me also add that I am sorry if anyone felt personally attacked by my comment it was not meant that way. It is a shame that it was not seen for what it was - a wry observation about the similarity of the initial responses. It was meant to evoke a wry chuckle, not merit the furore that ensued. A chuckle of the sort I would give if someone said to me "engineers are all the same the tell us the project will cost £1billiion and £2billion later they still haven't finished. go well

Ad hominem remarks do not strengthen a weak argument. When we hear from vetinary, medical and agricultural experts then I would agree they know more than I do. At the moment I can say that those responding know many things I don't but equally I know things they perhaps don't.

Since everybody seems to want to quote part of my first post in this thread I thought I would quote another part. As regards to the defensiveness of some to my comment about chemists, I thought it a bit odd that their response was the same as our glorious politicians through most of the Salmonella, CJD, BSE, foot and mouth and other crises viz 'everything in the techno garden is lovely and the only viable economic method' As a taxpayer who has been footing the bill for this 'economic method of beef farming by totally destroying a country's beef population' I feel I have a right to question this.

I can remember a few incidents in the university lab, back in the late 60's with bromine and hydrogen cyanide and old fashioned fume cupboards and also catching my sleeve on fire by leaning over a bunsen burner and not paying proper attention. Those were the days. I must also admit in a later life to being the surveyor who left a theodolite set up in the Strand in London over a weekend - yes I did get it back.

Seems to me that the answers here have been rather one sided and (no disrespect) from chemists whose interest should be declared. The question was 'what problems does organic agriculture solve?' not 'is it the most efficient?' or what problems does it not solve? Some problems it definitely solves or avoids are those associated with non organic techniques and practices. Whatever the final verdict on prion diseases they have never happened on organic farms. Whatever the benefits of organophosphorus animal dips there is a definite recorded increase in medical conditions (some very serious) amongst farmers and farmworkers who use them over organic farms where they are not allowed. As regards to the debate on which method is better, I don't see that it need be one or the other. Surely the logically correct way is to choose what is most appropriate from both camps?

Another fun formula (due to Wallis) is [math]\mathop {\lim }\limits_{m \to \infty } \frac{{2.4.6.8.\left( {2m - 2} \right)}}{{3.5.7.9.\left( {2m - 1} \right)}}\sqrt {2m} = \sqrt {\frac{\pi }{2}} [/math]

Well it depends upon what you want your number system to do; not all number systems incorporate a zero. Fo example the the counting or natural numbers 1,2 3, ..... have no zero, as you have observed with your measuring comment. However mathematicians like closed systems this means that we can use a symbol to represent a particular property of all the elements of such a system. Zero is that element which allows us to say For any three numbers a and b and c in our numbering system we can find a b such that (a+b) = c Now if a = c then we must find a b such that a + b = a and zero is this number for c.

That the total probability is exactly 1 is a fundamental tenet of probability, not to do with infinite series. Take a simple coin toss. The total probability = probability of all possible outcomes = (Pheads+Ptails) = 1

Imatfaal is using Bernoulli numbers and their connection to pi through series expansions. http://mathworld.wol...ulliNumber.html Other useful numbers are Euler's numbers and Stirlings formula go well Edit In this case we have The bernoulli numbers Bn are the coeffiecients of the series [math]\frac{z}{{{e^z} - 1}} + \frac{z}{2} = \sum\limits_0^\infty {{B_{2m}}} \frac{{{z^{2m}}}}{{\left( {2m} \right)!}}[/math] for even indices, with B1 = -1/2 and with all other odd terms zero. This evaluates even values of the zeta function [math]\zeta (2m) = {\left( { - 1} \right)^{m + 1}}{B_{2m}}\frac{{{{\left( {2\pi } \right)}^{2m}}}}{{2.\left( {2m} \right)!}}[/math] leading to [math]\zeta (6) = \frac{{{\pi ^6}}}{{945}}[/math]

'Vector' is obviously not the only word where physicists, mathematicians and others use the same word for different definitions. Edit Thank you qsa for those references. They appear to identify a wavefunctional with a definite integral or definite difference between a zero state and some specific state - and which is a real number and consistent with the maths definition. Can someone identify the units of this real number since electrons apparantly these?

Some interesting historical values for pi The Rhind Papyrus (1650BC) [math]{\left( {\frac{{16}}{9}} \right)^2} = 3.1604[/math] The Bible 3 Archimedes (250BC) [math]3\frac{{10}}{{71}} < \pi < 3\frac{{10}}{{70}}[/math] Tsu Chung Chich (AD 450) [math]\frac{{355}}{{113}} = 3.1415929[/math]

Discussion is only useless with those who won't listen. You made an all embracing sweeping statement "Electrons are particles" Now, I have a different understanding of the word 'particle' from yourself. Furthermore I claim grandfather rights on my definition of the subject since my definition goes back at least as far as Newton's corpuscles. However I have been prepared to listen and I now thank you for helping me update my view of the current state of particle physics. Having followed the discussion I do not see that you have proved your point. In fact you have failed to respond when I observed that your hero is lax with mathematical terminology. Your thesis is that we should take on trust the above statement apparantly because someone says so rather than on account of proof. Like all physics 'an electron' is a model. Models are useful when their response to a property of interest is the same or indistinguishable from the actuality. A particle is a model. In my view a particle is an entity where the entire property or properties of interest can be considered to act or be concentrated at one point. A particle need not be small that depends upon the nature of the system under consideration.

Surely the only definition of importance is the one employed by a poster making a point, rather than some hearsay definition from another source outside SF and this thread. I am particularly chary of a source which makes this sort of statement. A functional is a particular term for a mapping from a vector space of functions to the space of real numbers. How does any definition of a wave fit this?

Thank you for your answer however I am unable to spot a clear and unambigouus current definition of a particle, elementary or otherwise in post#131. I have quoted the part I think you are referring to but coloured the words which worry me. As I read this text it clearly states a historic definition and a refutation of this definition, but does not provide a current definiton.

What makes you think that the K-T extinction event (dinosaurs) destroyed all life? There have been five (known) major extinction events showing in the fossil record and the K-T was nowhere near the most extensive. That was the P-T event. You should look up both.

Hello VEI, Actually infinities and their applications are already pretty well defined in mathematics. Note I use the plural since there are many infinities. You should look up 'cardinality'. The fact that there are many infinities, some bigger than others is why we can often evalute expressions such as [math]\frac{\infty }{\infty }or\frac{0}{0}[/math] to yield a finite result

Man hat im 1987 diese buch verlangt. Is this modern?

Yes the vertical fin of the tail plane is more akin to a keel than a wing. Fish, of course have such devices - they are called fins. However the keel has an additional function. Its large area provides large resistance to the sideways component of force generated by an angled wind, as compared to low resistance offered by the streamlined shape in the forward direction. This is the significance of item 2 on my list. Incidentally in water the criteria are not supersonic/subsonic but super critical/subcritical flow. go well

There is also the issue of 'elementary'. I had always understood the word to mean indivisible (in this application into smaller/more fundamental particles) Does an electron meet this requirement?

Two big differences between a keel and a wing. 1) The asymmetry of the wing is designed to produce a force at right angles to the flow. If you did this with a keel the vessel would be permanentlt pushed sideways. 2) The driving force of an airplane has no intended component at right angles to the direction of thrust and motion.

Alluded, yes but stated, never. In particular I don't think you used the word 'elementary' to qualify the word particle before.