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Posts posted by Sensei

  1. 52 minutes ago, swansont said:

    I want to note for the record that when I had the chance to go to Albuquerque a few years ago, I made sure to make the proper left-hand turn, and ended up where I wanted to be.

    Who would have thought that cartoon can teach you something...



  2. @koti

    Galactic offworlders have specific sense of humour. Off this world.

    Human can laugh from getting lost in mall, hotel etc. and turn it to anecdote for friends and family.

    Offworlder can laugh from getting lost in space.

  3. 1 hour ago, Rameshais renk said:

    But leaser light in not seen in that video

    Author of the video could use IR, UV or edited video in post-production. People are making such videos every day to impress viewers, get audience and earn money on advertisements.

  4. On 10/16/2019 at 1:58 PM, NoIdentificationProvided said:

    Humans are designed to be lazy.

    Bullshit. You are using the wrong words. Organic life is trying to optimize energy. The easiest route, the smallest energy usage. If somebody invests time, money and effort, in building dam to provide energy, for further things, actually it is example of optimization of energy. Invest some energy in building device once, so device will work for you for years, instead of you in the future (or better in future generations)..

    Energy spend on learning at early stage of life + energy spend on learning things which are valuable (i.e. programming, high-tech etc. etc.) << energy spend on doing nothing at primary school + having no college + having no university + having low paid job as a result of the all previously taken "optimizations" at childhood..



  5. "Feeding mice helps them to fight viral infection, whereas starvation is a better strategy against bacterial infection — lending support to the proverb 'feed a cold, starve a fever'.

    Ruslan Medzhitov and his colleagues at Yale University School of Medicine in New Haven, Connecticut, studied the effects of feeding on mice that were infected with either the bacterium Listeria monocytogenes or an influenza virus. Bacterium-infected mice that were deprived of food stayed alive, whereas well-fed animals died. By contrast, almost all mice with flu died when they were starved, but most survived when they were fed. During bacterial inflammation, glucose from food inhibited a metabolic process that protects brain tissue from damage, whereas the sugar protected the brain during viral inflammation."



  6. 14 hours ago, Commander said:

    Sensei only 7722 will make it !

    Which is also double of 3861

    Correct answer.


    #include <stdio.h>
    int get( int i, int j ) {
    	j = 3 - j;
    	for( ; j > 0; j-- ) i /= 10;
    	return( i % 10 );
    int swap( int i, int a, int b, int c, int d )
    	int result;
    	result = get( i, a ) * 1000;
    	result += get( i, b ) * 100;
    	result += get( i, c ) * 10;
    	result += get( i, d ) * 1;
    	return( result );
    bool check( int i, bool verbose = false ) {
    	if( get( i, 0 ) == 0 ) return( false );
    	if( get( i, 1 ) == 0 ) return( false );
    	if( get( i, 2 ) == 0 ) return( false );
    	if( get( i, 3 ) == 0 ) return( false );
    	int j;
    	j = swap( i, 0, 1, 2, 3 );
    	if( verbose ) printf( "ABCD %d\n", j );
    	if( ( i % 13 ) != 0 ) return( false );
    	j = swap( i, 1, 2, 3, 0 );
    	if( verbose ) printf( "BCDA %d\n", j );
    	if( ( j % 11 ) != 0 ) return( false );
    	j = swap( i, 2, 3, 0, 1 );
    	if( verbose ) printf( "CDAB %d\n", j );
    	if( ( j % 9 ) != 0 ) return( false );
    	j = swap( i, 3, 0, 1, 2 );
    	if( verbose ) printf( "DABC %d\n", j );
    	if( ( j % 7 ) != 0 ) return( false );
    	return( true );
    int main() {
    	for( int i = 0; i < 10000; i++ ) {
    		if( check( i ) ) {
    			printf( "Result %d\n", i );
    			check( i, true );

  7. 12 hours ago, swansont said:

    The display of a 5 vs. 6 on an 8-segment display is different by just one element. It is possible (though not certain) this is a display problem and not a computational error. Though if it is consistently wrong, that points away from that being the issue. One would expect this to be intermittent if it were a display problem.

    Yeah. Good idea. Simply check if number 8888888888(8) will have some parts missed..

    LCD display problems are the most common way how calculators (and electronic multimeters in fact) are ending up their life being useless.



  8. Quote

    Antibiotic resistance. Suggested tactics

    Antibiotics fight with bacteria. Bacteria can have altered DNA by viruses. There could be prepared custom virus attacking just enemy bacteria at interest. It does not even have to kill bacteria. It could just change bacteria DNA in such a way to have slower rate of reproduction, or change them to being antibiotics helpless again, reversing acquired resistance.


  9. On 10/15/2019 at 12:26 PM, Commander said:

    There is a four-digit number ABCD, where A, B, C, D each represents a different digit from 1 to 9.

    Since original puzzle has been solved, I have puzzle for you Commander: what four-digit number will be solution, if any digit might be used multiple times.

  10. On 10/10/2019 at 3:03 PM, Phi for All said:

    I think there will always be some evil around, but I agree that obsession with money is hurting our global development. Rather than do away with it, I'm more of a fan of using it as the tool it is. Rather than doing away with it, I think we'd be smarter to use all our economic tools rather than just private ownership. We should remember that democracies were established partly so the People could own part of their lives, so the King/Queen didn't own everything. 

    I also agree that education is more important than ever. Our biggest flaw in modern times is that we don't know what we don't know. Ignorance encourages emotional reactions that often run counter to critical thinking. How great would it be for all people to use reason first, then get emotional about THAT?




  11. On 10/10/2019 at 4:24 PM, NoIdentificationProvided said:

    As a member of this generation, I have relatively large expectations. What impresses my predecessors may only get a nudge from me. From my point of view, we are growing at a rather slow pace. What I asked was how to accelerate it.

    It is mathematics. If you start from low base e.g. variable x=1, then growth by 1 to x=2 is 100% increase. Huge! Then growth from 2 to 3 is just 50% increase. Then increase from e.g. 100 to 101 is just 1% increase.

    Start improvement from yourself. If the rest of people will do the same, then we will have global improvement of humanity.

    Do you have smartphone, tablet, computer, laptop? (obviously yes!) Write app for it. Instead of buying and/or downloading ready one from store. During development of some app, you will see how much you did not know.. You will gain a lot of knowledge. Every day, one project. Or if you are slow learner, every week, one project.

    Get Arduino or other microcontroller. Build electronic device by yourself. Program it so you will be able to remote control it from your smartphone and/or tablet through Bluetooth and/or WiFi. e.g. read temperature and/or pressure from environment and store on SD/SDHC card, every second in CSV file with time read from real-time clock, with Bluetooth connection to it to download file from SD/SDHC. Later you will be able to load it in OpenOffice Spread Sheet and/or Excel, and analyze gathered data. Every week, one project.

  12. If you would merge two layers of polarization filters. One with e.g. p-polarization, and second one made by material which is able to rotate polarization vector due to applied electric or magnetic field, in such a way that will be opposite axis e.g. s-polarized. They working together would be creating opaque (black) material on demand.



    "Pockels cells are used in a variety of scientific and technical applications. A Pockels cell, combined with a polarizer, can be used for switching between no optical rotation and 90° rotation creates a fast shutter capable of "opening" and "closing" in nanoseconds. The same technique can be used to impress information on the beam by modulating the rotation between 0° and 90°; the exiting beam's intensity, when viewed through the polarizer, contains an amplitude-modulated signal. This modulated signal can be used for time-resolved electric field measurements when a crystal is exposed to an unknown electric field.[2][3]"



  13. Chickens require less nutrients to grow up than pigs and cows (which also produce methane gas). They are also cheaper and healthier for customer.

    Fish farms are better for environment than fishing of wild fishes. Their population is under control of human. Fish farm does not deplete natural population of fishes, so they can reborn.



    "Higher protein or calorie retention means higher efficiency.

    The results show that, on average (weighted according to global production levels of the nine aquatic species studied), 100 g of protein in aquaculture feed will be converted into 19 g of protein for the human food supply (19% retention), and that 100 kcal of aquaculture feed will be converted into 10 kcal for the human food supply (10% retention). Protein retention ranges from 14%–28% for the aquatic species studied, and 13%–37% for the land species. Calorie retention ranges from 6%–25% for the aquatic species and 7%–27% for the land species. The best performers across all species considered are chickens, followed by Atlantic salmon."





  14. 8 hours ago, OldChemE said:

    This is the kind of problem that is more easily solved if you step back before turning the math crank.   Look at y = x^2 and y = 16&x.  y = X^2 is a parabola that passes through the origin.  y = 16^x is an exponential function, and on the positive x side it rises faster than the parabola-- so it is obvious that there will be no solution for x > 0.  On the negative side of the graph, 16^x approaches zero asymptotically, and is already 1/16 when x = -1 (while at x = -1 the parabola is at y = 1). Thus, it becomes obvious that the solution must lie in the region -1 < x < 0. I did a quick sketch of the two functions and it was equally obvious the crossing point had to be somewhere close to -0.5, as stated by Studiot.  Understanding the shapes of functions makes trial and error, and heavy math, both unnecessary.

    You can use Wolfram Alpha to plot two graphs, so you can see whether and/or where they are crossing each other..



    With limits x = -1 ... +1



  15. 11 hours ago, mistermack said:

    But today, with modern forensics, it's possible to solve a lot of serious cases without relying on the weakness of human memory. DNA is a prime example, but fibre evidence, ballistics and even photographic evidence have the potential to be reliable evidence way into the future. Plus stuff that hasn't been thought of yet. 

    You are mistaken over-trusting DNA, to catch true murderer after many years. Because it might be as well misused against incorrect innocent person.

    I will give you examples how it can put somebody innocent to jail, or even sentenced to death, or life in prison:

    - imagine you have girlfriend, or girl for one night met at club, have sex with her at night, she is going early to job, leaves your apartment early and somebody is attacking her in the middle of route, but leaves no his DNA, or leaves DNA. Now, police officers are checking DNA on the body, and find it is yours. Are you murderer? Are you rapist? Did you participate in multi person rape on her? No, you just had normal sex with her.. But you are unlucky that she has been attacked right after it.. Even worse if police finds out you had argue through SMS or Internet with her, just before somebody else attacked her..

    - imagine you are working at mall. Yours responsibility is to put bottles with beer, wine, vodka, whisky etc. to refrigerator or simply on shelf. Client takes bottle. And many hour later it is used by somebody on the party as weapon (broken bottle), and somebody dies due to injures. Again, police officers are checking tool used to commit murder, and find out your DNA on it... Again, you can be mistakenly sentenced by court, innocent person put to jail, thanks to DNA found on tool used to committing crime..

    If police had your DNA because you are in database already, they will find you immediately, and you have immediate troubles,

    but if not, they have "trace", and many (dozen) years later DNA from that crime scene can be compared with your DNA and match! Match, but not the true murderer!

    ps. My post is not against "statue of limitations" nor for it.. but just not to have absolute trust in DNA, even if it matches..

  16. 13 minutes ago, FrancoK said:

    Air pollution has caused nearly four million deaths, where the deaths are mostly related to respiratory diseases

    Apart from cancer, pollution of air can cause pneumoconiosis.


    Dust obviously has the highest concentration in coalmines, silica mines, factories processing ores and surrounding them areas. Therefor industry workers are the most affected by it.

    "In 2013, it resulted in 260,000 deaths globally, up from 251,000 deaths in 1990.[4] Of these deaths, 46,000 were due to silicosis, 24,000 due to asbestosis and 25,000 due to coal workers pneumoconiosis.[4]"


    Read pathogenesis section in the above article.

  17. 36 minutes ago, NoIdentificationProvided said:

    What can we improve in this world of ours?

    Human can get rid of money and the all evilness associated with them i.e. there will be no thieves, there will be no murders to kill witnesses of stealing, there will be no corruption, there will be no hunger, no people dying unable to buy food, medicament or unable to afford health care, there will be no poor, nor wealthy, no greediness nor jealousy of possession of things you don't have but others have.. no drug dealers, nor drug wars.. People will be well educated, if they will be intelligent enough to use free of charge universities..

    In the distant past, people lived in small villages, each other voluntarily helping other members of community because of goodness from the bottom of their hearts..

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