• Raja Success asked a question:
    Differnce between Access Latency and Tunning Time in VANET?

    Hi Friends, How to measure Access latency and Tunning Time in Vechile Ad hoc Network?

  • Lotfi Zeghadnia added an answer:
    How to compute Lambert Function (W)?

    Lambert function has been proposed by Jean-Henri Lambert, some times called Omegat function (W).

    the equation can be written as following:

     xexp(x) = z  this means that x= W0(z)

    So the question is , how can i compute W0?

    Lotfi Zeghadnia

    Dear Mykola Kozlenko:

    The doc is interesting, thank you So much  for your contributions.

  • Andrei Nikonov added an answer:
    Why transfiction of Hela cell line is not perfect at all every time, while 293 is usually transficted?

    What is the defect behind this relating to Hela strains ?

    Andrei Nikonov

    use electroporation for HeLa, exponential pulse 180V, 975 uF in 0.4cm gap cuvette with 250 uL of cell suspension in IMDM full medium (electroporation machine is GenePulser from BioRad), and dont forget to add carrier DNA (herring sperm DNA ~50 ug) to your plasmid DNA (typically, 1-1000 ng).

  • Ingo H. Leubner added an answer:
    P300 based speller design - Is Row column information necessary ?

    Is it possible to classify the character without knowing the row-column information?

    p300 signal is generated when human are looking at flashing light. From the EEG signal correctly detection of p300 is important. After detection of p300 our job is to find what time this p300 signal generated and at that time instant which row or column flashed. From this row-column combination we can get the original character.

    Now if I don't have the row-column information. Is this possible to detect the character from EEG signal?  

    Ingo H. Leubner

    Sourav ,if  Row column information works, learn from it. However, you can also try ellipses, hyperbolas, and the form of the Spirals of the Milky Way. Since I am totally ignorant of your way, All I can and will do is to  encourage you to answer your question yourself and become in the process a successful Scientist! It worked for me and many others. Cheers, Ingo H. Leubner Dr. rer. nat. 

  • Sergey Shevchenko added an answer:
    Is the flow of time an illusion?
    This has been discussed on ResearchGate in a rather ad hoc way in relation to another question about the absolute immutability of some physical laws but it really deserves its own separate discussion. Below I summarise the arguments in favour.
    The philosophers
    The nature of time has been the subject of discussion by philosophers for 2000 years or more. In the last two decades their views have crystallised. If time flows - (1) How do we know? and (2) How do we measure its speed? In other words - what frame of reference can we use to measure time?
    The philosophers' conclusion is that they would have to invent another time dimension for the purpose but this would then need a third time dimension and so on ad infinitum. This would be absurd and so they conclude that the flow of time is an illusion.
    Relativity, Einstein and Godel (A World Without Time - Palle Yourgrau - Penguin Books, 2005)
    According to the theories of relativity two observers can never agree on the simultaneity of two events that both witness and neither has a "preferred" position that makes one of them correct. This implies that all events already exist and that what we perceive as the flow of time is an illusion.
    Godel showed that rotating universes were consistent with relativity and proved that in them it was possible to travel back in time. He immediately realised that this implied that the past must still exist and that what he called "intuitive time" is therefore an illusion. In 1949 he published a formal proof that time (in our intuitive sense) cannot exist in any universe. This uncomfortable discovery was ignored for nearly half a century but was revived by Julian Barbour in "The End of Time" and is now widely discussed and accepted by many physicists.
    The Laws of Physics
    The fundamental laws of physics describing the forces are time-symmetric.
    What can we say about the time dimension?
    Time still exists but only as a chronological map in which events are located;
    Time is not in any way like the spatial dimensions because:
    It is anisotropic and contains an entropy gradient;
    If we exist in more than one location in any of the spatial dimensions then we will also always then be in different locations in the time dimension;
    Separations in 4 dimensions are extensions of Pythagoras's Theorem but have the form:
    separation = √[x2 + y2 + z2 - (ct)2], which means that time measurements are imaginary (ict) where i=√(-1), as Hawking suggests in "A Brief History of Time".
    Free will is also an illusion
    We live all our lives all the time but every instant feels like "now"
    Time travel is impossible because (a) there is no dimension in which travel is possible, (b) we occupy all the spacetime of our lives and cannot take back to an earlier time our memories of a later time.
    Sergey Shevchenko


    It seems you didn’t read the “The Information as Absolute” paper till now, where, for example it is rigorously proven that the “nothing” cannot exist.

    (See, also, SS posts on 8-th and 10-th pages in https://www.researchgate.net/post/why_is_there_something_instead_of_nothing/10 )

    And where it is pointed out, that this fact follows just from the ultimate fundamentality of the notion “the information” – the data “there is nothing” is an information and so belongs to the “Information” Set. Moreover, the “nothing” as an element of the Set, contains whole Set – as every other element of the Set – a particle, a human’s consciousness, an infinitesimal spacetime point, etc.

    At that the “Information” Set, which is absolutely fundamental and absolutely infinite Set, exists always, because of any information cannot be non-existent principally, i.e. “in absolutely infinite long time” (though, generally speaking, the last isn’t a rigorous claim, since relates to the notion “time”, which acts in concrete different ways in concrete diffrent changing structures).

    But indeed, we cannot exclude something that existed before “always” (and, for example, could generate the Set) – when we consider absolute infinity, where, in principle such situation is possible.

    An example  - even in the case of the continuum, which has the cardinality that absolutely infinitely lesser then the Set’s cardinality, we know that the “number of points” in, say, 1 angstrom interval, is equal to the number of points in, say, the  light year interval, but if one chooses an 1 angstrom interval in a light year interval there is evidently non-zero number of points that are before and after the choused interval.

    Similar situation, is of course, possible  for the Set – the Set is highly complex and paradoxical set, Her has a lot of very interesting properties that must be studied by mathematics, where mainstream claims till now that absolute infinite set doesn’t exist.

    Returning to the “Something that could generate the Set” – this Something is “more then absolutely” undefined, in the information there is no instruments to perceive such notion.  But for humans this fact is inessential – in the Set all have happened  always, “absolutely long time ago”; and always  is happening [for living in given cinema move humans] “now”, when the possible Set’s Creator cannot change anything in the Set.

    As to “Achilles and Tortoise” problem – no comment, all see in the SS posts above.


  • Krishnan Umachandran added an answer:
    Does anyone known studies about the social use of time?

    I'm interested in studies that relate the use of ICT and the social use of time

    Krishnan Umachandran

    This data collection represents an attempt to apply recent methodological developments in the measurement of time use to a national probability sample of United States households in order to facilitate development of a fully articulated system of economic and social accounts.

  • Sudip Mukherjee added an answer:
    Why does my silver nanoparticles wavelength decreases after 120 days from 455nm to 435nm?

    I prepared silver nanoparticles and I checked UV-Visble spectroscopy at that time I found absorption maximum for silver nanoparticles at 455nm after 120 days again I checked at that time I found the absorption band at 435nm. For this solution zeta potential is 35mV. Reason for wavelength decrease? Generally wavelength increases means new particles formation takes place but decrease means? 

    Sudip Mukherjee

    You can check the particles stability by either DLS or TEM to be sure.

  • Fatima Khalid added an answer:
    How can I apply cyclic loading in TNO Diana?

    I have to apply a displacement on frame which is varying with time and it is cyclic. I have midas FX+ Modeller

    Fatima Khalid

    I have applied cyclic loading as a base function command (displacement varying with time). I did nonlinear analysis, so i used time steps. But after analysis, the displacement is not showing to and fro motion. I have attached the pictures for reference

    + 1 more attachment

  • Noureddine Ouerfelli added an answer:
    How you organize your work and time?
    Do you plan things out in microdetails or you are a spontaneous person?
    Noureddine Ouerfelli

    When we know what the priorities in our specific conditions are, we will see how to organize our work and time, which can change for the same person, from a time to time.

  • Erkki J. Brändas added an answer:
    What caused space and time?

    Space and time don't exist obviously without matter. The assumption is incorrect respectively wrong that space and time are objective present or existing and the matter only overmoulding or modelling space and time. Space and time are products or effects of the objective existing matter. Insofar Einstein was putting the cart before the horse.

    In mathematics you can assume or conceive an objective and infinite space and time. But nowhere in universe you can find the same conditions or properties for the space and nowhere is a clock that shows an universe-time. If you could leave the earth, space and time would modify and you couldn't perceive because you take part on the changes.

    Our thoughts are determined by terrestrial clearness, mathematical ideas and many unproven theories. I can't share the view that the reality is nearly recognized.

    Erkki J. Brändas

    Two fermions compacted (whatever this means) can never be a fermion. This was one of the big problems in the pre-neutron era. The neutron, as an elementary particle of the atomic nucleus, turned out to be commensurate with fermionic statistics and hence the portrait of a neutron as having the constituents of a proton-electron pair violates this result – the latter entity commensurate with bosonic character.

  • Marc Tessera added an answer:
    A question on Time as an emergent property
    Time can be viewed as an emergent property : whenever any change occurs anywhere in the universe - in other words whenever the state space of the universe undergoes any change - then Time itself happens and 'notches up' one tick (at least in the 'neighbourhood' of the change, which is a separate discussion.)

    But isn't this circular reasoning ? For a change in state space to be able to occur in the fist place, isn't the pre-existence of something like time a prerequisite ?

    The only way out of this conundrum is that all elementary state space changes must happen out of time, i.e. instantaneously (with a delta time = 0.) But this would then require the superimposed coexistence of 2 elementary state spaces. Can this happen ? We could probably engineer a situation where the Pauli exclusion principle would then be violated. This would tend to prove that Time as an emergent property cannot be the whole story?

    Any comments?
    Marc Tessera


    "You need not agree with him".

    Of course, I only ask for comments as it is an interesting hypothesis of the origin of "time" and such an hypothesis, if true, would mean that it is quite possible to envisage a timeless world (lets' think of the "big bang" state).

  • Joseph Emmanuel Mullat added an answer:
    Before the big bang, did time exist? If it did, is time invented by man or God's creation?
    I believe time is a measure of duration, and man invented clock to measure time. Therefore there should be an empiricism that explains the time that dark matter and dark energy existed before the big bang
    Joseph Emmanuel Mullat


    Yes indeed,

    Time has been invented by man. However, we can replace the time indicator of Universe dynamic by the matter density. In some sense the density correlates with time. Therefore, we can assume that in the beginning the density was equal to zero (no matter existed), and the singularity problem disappears. It can be like some energy field existed before the density in some point in energy field suddenly transforms into matter of positive density – known as initial inflation phase of the Big Bang. Thanks

  • Roy Lisker added an answer:
    Within the framework of quantum mechanics, what accounts for the apparent irreversibility of time?

    Within the framework of quantum mechanics, what accounts for the apparent irreversibility of time?

    Roy Lisker

    The scribble above is an error! I'd meant to write something detailed, but it got lost in transmission. To recapitulate: A "direction" is time is a geometric notion, and not necessarily appropriate to the phenomenon of time. One brings in geometry through causation, and ultimately through relativity, which turns time into a linear dimension akin to length.

    All quantum measurements are classically recorded. Two observers A and B, looking at the same quantum level phenomenon going from C to E (cause to effect) will, of course compare their classical measurements and assume that they are going in the same direction, ie from cause to effect. But what happens in the classical realm need not pertain to the quantum universe. Ultimately, the only way to determine time in the quantum level is to buld a "quantum clock". In previous communications I've given reasons to argue (based on the Uncertainty Principle), that a "quantum clock" would be inherently self-complementary, so that one cannot build such an instrument. And anything that cannot be measured is no longer relevant to physics.

  • Richard Epworth added an answer:
    Does anybody know about recent good articles on the changing perception of time and space in the digital world (interdisciplinary welcome!)?
    I am looking for different approaches from neuroscience, philosophy, communication science, sociology etc.
    Richard Epworth

    Miriam: Not sure if it is of any use to you, but I have explored the limited information rate for perceiving novel information, from the perspective of information science, i.e. bits per second:

  • Ariel Linden added an answer:
    How can I analyse correlation in Panel data analysis?

    Can anyone help or guide on how to analyse correlations of variables in Panel data analysis  I have to remove few variables(both time variant and  time invariant)  to improve Adjusted R(square). I am using R .

    Ariel Linden

    I would start with a pooled matrix, which would basically look at the fixed effects variables of your model. You could certainly go beyond that, but I am not sure how easy it would be to interpret the correlations at various time points in the broader context.

  • R. Stan added an answer:
    A mental time travel?
    There is connection between thoughts past, present and future?
  • Arbind Kumar added an answer:
    Could gravitation have affected evolution of DNA ?

    Hi, I am wondering whether evolution of DNA molecule would have been influenced by the gravitational curvature of space-time continuum giving DNA molecule a double helical shape. Any comments are welcome.  

    Arbind Kumar

    Dear Professor A. Sepehri ,

    Thank you very much for your lively, interesting and valuable discussion. Some fields of science particularly related to cosmology/astronomy are largely ignored. One of my research paper entitled ' EVOLUTION AND RELATION OF MICROCOSM AND MACROCOSM' showing correlation between Genetic Code and Solar System is posted on ResearchGate. I am sending you the Link   

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: ( Excerpts from my research paper "EVOLUTION AND RELATION OF MICROCOSM AND MACROCOSM" with edition ) The present study implies that the two parts of nature, biological universe and physical universe, are intimately correlated, a fact which has always been overlooked. The investigation points out a definite correlation between the organizational plan of DNA molecule and cell during organic evolution and the organizational plan of our Solar System during inorganic evolution. The following equation showing the correlation between the genetic code and the apparent motion of the Sun, due to Earth’s revolution around the Sun, has been derived by me during the present investigation. (64 – As) / 20 = 339 / 107.65 Where, 64 = Number of codons 20 = Number of amino acids As = Astromolecular constant i.e. 1.013, derived during the present Investigation 339 = Number of disks of Sun to measure its apparent path along the ecliptic in Celestial sphere between the two equinoxes . 107.65 = Average distance of the Sun in terms of its own diameter All living organisms on the earth share the same 64 codons and 20 amino acids. The above equation correlates the molecular data with the astronomical data implying a common organizational plan of the DNA molecule and our Solar System probably due to the influence of a common governing force i.e. Sun’s large gravitational force.Also the nebula shaped like DNA and biomolecule DNA both might have been formed and shaped under the influence of universal gravity. The genetic code made up of DNA, acts as an intracellular computer for the structure and physiology of the cell and governs the embryonic development leading to the formation of the body plan of the organisms. The data of the present investigation clearly show that the microscopical numbers i.e. the number of codons of the genetic code, number of amino acids which are common to all organisms, are functions of the astronomical numbers as shown in the above equation derived. The genetic code works as an intracellular computer which governs the organization of the cell and nucleus and the phylogenetic evolution of living organisms. This intimate correlation found between the biological and physical universe during the present investigation, and the electron microscopic structures of different types of cells and tissues observed during my studies and their comparison with telescopic pictures of the universe taken by me and many astronomers, have led me to hypothesize that the physical universe is like a living system or organism. The phenomenon of accretion of gas onto a massive black hole at the galactic center and the jets of material ejected from the accretion disc around a black hole, which expand and decay over a few days, or the explosion of supernovae and their remnants may be analogous with the biological phenomena inside living organisms like secretion of substances used by the body. The process of stellar nucleosynthesis and formation of stars in the nebulae may be analogous to the synthesis of substances in the living organisms. Pulsating system and phenomenon of pulsations observed in the universe like stellar pulsations are analogous to pulsating system in the body like pulsations of arteries in tune with the heartbeat. These analogies existing on the two different scales of space and time might appear unrelated initially. So, in my opinion all the activities observed in the universe are its life activities like vital activities of our bodies. The universe has two coordination systems like human body which brings integration in the whole universe. The two systems – Neural Coordination and Chemical Coordination which controls and integrates the different activities and structures of human body, may also be controlling and integrating various structures and activities in the universe. The telescopic pictures of the universe observed by me and many astronomers very much resemble the microscopic pictures of the nervous system particularly brain, observed during my present investigation. Astronomers have taken the pictures of interconnecting filaments of star clusters and clusters of galaxies that form the texture of the universe and connect our Galaxy to the vast expanse of the universe. One of these filaments of groups of galaxies and star clusters surrounded by immense voids is considered like the umbilical cord that fed our Galaxy during its youth. These filaments of clusters and superclusters of galaxies, arms of spiral galaxies and other such trabecular strand structures in the universe resemble the branches (dendrites and axons) of the nerve cells of brain in particular and of nervous system in general. DNA, the blueprint of all living organisms on the earth, is involved in all vital functions like protein synthesis and production of energy. The ultimate result of these vital activities is consciousness. Similarly the blueprint of the universe may be producing matter & energy which along with other activities of the universe might result in large scale consciousness i.e. super-consciousness. In my opinion, this super-consciousness is the driving force of everything in this universe. From tiny world of atom to the vastness of universe, there are integrated levels of organization including all living organisms. The whole universe is a living entity or organism and we are like microorganisms or micromolecules or macromolecules. Evolution of life is progressing through different levels of dimensions and the universe is the highest dimension of life with super-consciousness which drives and shapes everything. We are all small and ephemeral part of greater and eternal living entity, the ultimate living universe. The organization of life is key to the organization of physical universe. The correlation of the genetic code (DNA) with the Solar System in particular and with the universe in general observed during my present investigation clearly implies that coding of DNA molecule has been very meticulously planned and regulated, because DNA has evolved in a four dimensional space-time continuum which is influenced,curved and distorted by gravity. I propose that knowing the biology better will solve the mysteries of the universe better. Sometimes it is Big-bang hypothesis and sometimes Contraction hypothesis; redshift and blueshift. My alternative hypothesis is that the universe is living, conscious and it has a thinking mind, and so follows the rules of life including growth and decay. Because the universe is a living system, it is aging naturally. The abnormal activities observed in the universe indicates its senility. Like living organisms the universe will one day die down. The advent of new generation of astronomical instruments opens new windows for the astronomers and may call for major revisions in the standard view of cosmology. My proposition is that an extensive and well co-ordinated work between different types of microscopes and telescopes could be able to reveal more mysteries enveloping the microcosm and macrocosm and thus bridging further the gaps between the disciplines like biology, chemistry, physics and astronomy.
  • Charles Francis added an answer:
    How did Schrodinger concluded that adding a complex number to wave function is important? What's the physics behind that?

    The wave function is complex, Why? Can the time and position for elementary particles have a complex relation (transformation) relative to our time and position?

    Charles Francis


    Briefly, one may start with probabilities for the results of measurements of position. Gleason's theorem enables one to put the probability density functions into direct correspondence with states in Hilbert space, and Stone's theorem enables one to establish that states in Hilbert space satisfy a Schroedinger equation. 

    Momentum states are defined by by superposition of position states, using the Fourier Transform. The Heisenberg uncertainty principle follows directly. 

    You may find the mathematical details on my website and in my papers. This is not a new approach to quantum mechanics, but I have tried to clarify an established approach which many physicists find obscured by mathematical formality.


  • Martin Stutzmann added an answer:
    How do I pick up CO from Au(111) with STM tip?

    I want to pick CO molecule from Au(111) surface by STM tip to prepare CO functionalized tip. CO molecules on Au(111) are movable. I tried many times, but it too difficult to pick up CO from Au surface. Do you have any suggestion?

    Martin Stutzmann

    CO binds more strongle to Pt than to Au. So you might try a Pt/Ir tip.

  • Joseph Feulefack added an answer:
    What is the role of the train planner with regards to the below mentioned?

    The key strategy, facts and principal elements a train planner needs to consider when compiling a train plan with regards to the sectional running times, station dwell times, the layover times and the engineering, pathing and perfrmance allowance to bear in mind.

    Joseph Feulefack

    Another video that may help:


  • Mohamed El Naschie added an answer:
    What happens if we reverse time in the Stefan (phase transition) problem ?

    Or to make it simpler just change t into -t  in a parabolic type equation, e.g. heat conduction equation? Will it become an ill-posed problem? Will it have a physical meaning? I came up with 1 example when it has for the Stefan-type problem with phase changes.

    Mohamed El Naschie


    Scholarly articles for el naschie time symmetry breaking
    Time symmetry breaking, duality and Cantorian space- … - ‎El Naschie - Cited by 70
    On the uncertainty of Cantorian geometry and the two- … - ‎El Naschie - Cited by 303
    Fractal gravity and symmetry breaking in a hierachical … - ‎El Naschie - Cited by 49

  • Azlan Muharam added an answer:
    Can anyone comment on the performance of using FPGA and GPU for image processing ?

    In term of time, latency, throughput,area and slicing

    Azlan Muharam

    many thanks for those ideas and comments really appreciated.

  • Richard Epworth added an answer:
    What are the timescales of perception and memory?

    When does perception end and memory begin? This question is rarely considered but has important implications for the science of psychology.

    Folk intuition suggests that perception ends once the object of experience is no longer stimulating the senses. However, this demarcation lacks scientific rigor and is inconsistent with many physical theories of time.

    Take for example time considered as a spacetime continuum. Meaningful events that unfold relative to an organism are always defined by time-like intervals. Therefore, the use of spacetime as a model for time in psychology would lead to the conclusion that every experience is memory-based.

    I would be happy for any contributions you might have to this discussion!

    Richard Epworth

    Brandon, you might be interested in the surprisingly low information rate of learning novel information (a few tens of bits per second maximum). This would suggest that we retrospectively construct an internal narrative that makes sense of sensations. In addition, the briefest glance can capture around 50 bits of information that is subsequently processed and memorised.

    + 1 more attachment

  • Martin Ritterath added an answer:
    Does anybody know any continuous function in time domain whose frequency response looks like the attached figure?

    I want a function in time domain whose frequency response should be of the form shown in the following figure.

    Martin Ritterath

    Yes, interpolate the polynomial and do invers Fourier transform.

    Good luck

  • Durga Prasad added an answer:
    Can I use omnetpp-4.6-src-windows with inet-2.99.0-src.tgz and Castalia-3.3?

    If install the versions of all this program together, is it ok?  because some times we must use older version. i would like make sure no problem will happen.

    Durga Prasad

    But for BAN ( Body Area Networks) you can use Castalia and Omnet++. There are manuals for both..

  • Suman Maroju added an answer:
    How can I use pdf in Matlab to plot a graph?

    I have time period values on the X-axis and the probability of an event occurring at a particular time on the Y-axis.

    Suman Maroju

    y = pdf(pd,x)

  • Ahmed Dhamad added an answer:
    As a part of preparing TBE buffer, can we keep the EDTA solution after preparing it for a week before autoclaving it?

    Hi every one, I am going to prepare a TBE buffer, and the EDTA preparation takes a long time, so can I keep the EDTA without autoclaving for a long time until I get ready to do so.

    Ahmed Dhamad

    Hi Muna, Yes, you can 

  • Sh. Arshadnejad added an answer:
    Is there an equation relating time and concrete strength?

    Is there an equation relating time and concrete strength?

    Sh. Arshadnejad


    You can find a general model to predict of concrete strength in due time, in a reference book about concrete. It is Concrete properties by Professor Novill.

    Thanks a lot

  • Junfu Bu added an answer:
    How can I determine the parameters to prepare a pellet?

    I wanted to prepare a pellet from a powder using a uniaxial press and a matrix attached to a pump, but with the pressure and the holding time that I have chosen, the pellet obtained breaks up.
    Are there a way to determine the correct pressure and holding time before launching tests?

  • Ahmed Dhamad asked a question:
    How many times can we use GE Healthcare GSTrap FF, 1 ml?

    How many times can we use GE Healthcare GSTrap FF, 1 ml, which is an affinity chromatography column that can capture GST taged-protein ? 

About Time

The dimension of the physical universe which, at a given place, orders the sequence of events. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

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