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  • Juehui Shi added an answer in Granger Causality:
    Im really not good in this field! my variables were not co-integrated, can i proceed further to test for a shortrun relationship?

    i am also doing a Granger causality test, does it mean i can use VAR in difference to test for the causality, since the variables are not co-integrated?? and lastly, does it mean my result will be spurious? thank youuuuu.

    Juehui Shi · University at Buffalo, The State University of New York

    You can detect cointegration by using Engle-Granger or Johansen test and then apply VECM if cointegration is present.

  • Andrey Borodach added an answer in Hagfishes:
    What is known about the gallbladder of the hagfish?

    The hagfish (Mixinidae) are seemingly the descendents of the most ancient animals on the planet developed the gallbladder. It would be interesting to learn more of the oldest gallbladder anatomy, function, and histological traits. This may shed also some light both to its normal function and the spectrum of its congenital disorders. The sketch drawn (after Gorham & Ivy, 1938, with changes) and provided below is my attempt to show the putative evolutionary tree of the gallbladder having about 500 million years.

    Andrey Borodach · Novosibirsk State Medical University

    Dear prof.Enzo,

    Thank you very much for both the reference and kind attention for my question!

    The paper is seemingly not exactly about the hagfish gallbladder judgingn by its title. However, there should be a list of references. So, it may become the key to start the investigation.

  • Arno Gorgels added an answer in Unified Theories:
    What is the lifetime of the proton and how do we understand it?

    It used to be considered gospel that protons, unlike, say, neutrons, live forever, never decaying into smaller pieces. Then in the 1970's, theorists realized that their candidates for a grand unified theory, merging all the forces except gravity, implied that protons must be unstable. Wait long enough and, very occasionally, one should break down. The trick is to catch it in the act. Sitting in underground laboratories, shielded from cosmic rays and other disturbances, experimenters have whiled away the years watching large tanks of water, waiting for a proton inside one of the atoms to give up the ghost. So far the fatality rate is zero, meaning that either protons are perfectly stable or their lifetime is enormous -- an estimated billion trillion trillion years or more.

     (taken from http://www.oglethorpe.edu/faculty/~m_rulison/top10.htm)

    Arno Gorgels · Principia Naturae

    May my dear disliker here above produce an argument or start studying to fill the gaps in his knowledge. 

  • hu Jing added an answer in Density:
    How to select the damping factor vetor?

    I  encountered an inverse problem described as following

    AX=b,     a ill-posed problem 

    where A is a matrix with n by m ,X is a vector with m by one,b is a vector with n by one.

    when we solve the equation,we will get the solver that is unstable because the condition number of  A matrix  is large.

    then some ones add the damping factor into the daigonal elements in matrix ATA.

    the least-square solver is


    If the vector X (we can say that the model parameters)contains only one kind  data, the apha we used can be constant.

    But the matrix A contains kinds of data that the scale of them varies very much(eg: the velocity 2000m/s,the density 2.65 g/cm3 ,so 2000 is much larger than 2.65),the damp factors to velocity and to density will be not the same.

    Please help me  with some useful ways to select the best damping factors!

    hu Jing · University of Science and Technology of China

    thank you very much! the method you suggested is very good,and may be useful to my problem。The way to select damping factor is like L - curve,or GCV and so on.but it is only for a constant damping factor,i want to add a damping vector (not damping factor multipe the unity matrix I) into the diagonal elements of A'A matrix.the elements in the damping vector  are not the same,and how to solve this problem.

  • Baravan A. Asaad added an answer in Pdf:
    How can I change the uploaded publication against another version?


    Some time ago we uploaded a pdf version from arxiv. I have a better, more comprehensive version, which I want to interchange against the uploaded one. How can I do that?

    Baravan A. Asaad · Universiti Utara Malaysia

    I think you can't interchange the new pdf with the old. So what you have to do is either remove the first pdf (you'll loss all information about it) and then add the new pdf or keep the first pdf and add the new pdf.

  • Marcel M. Lambrechts added an answer in Qualia:
    How to define human consciousness?

    After many years of discussion of the concept of human consciousness, I arrived to the following definition:

    “Conscious processes are qualitative experiences that contain at least four kinds of ingredient:

    a) Sensations and feelings (such as hunger, thirst, happiness, sadness, fear, pain, pleasure);

    b) Perceptual qualities or ‘qualia’ (such as colors, sounds, smells, tastes, etc.);

    c) Cognitive processes grounded on feelings and ‘qualia’, such as attention, thinking, memory formation and recall, etc. and

    d) A spatiotemporal structure, composed of an egocentric spatial framework (according to the work of Arnold Trehub) and a temporal duration of (conscious) episodes of 100 milliseconds to 3 seconds (according to the work of Ernst Poppel)”.

    This definition does not include the controversial concepts of “Self” and “Free Will”.

    I basically agree with David Hume and Thomas Metzinger that the concept of Self is a product of conscious activity, not a metaphysical soul to be considered as a pre-requisite for the definition of consciousness. What is implied by the above definition is the existence of a body that is the bearer of experiences, and also is affected by them. In this sense, the definition is close to the phenomenology of Maurice Merleau-Ponty.

    The feeling of will is relevant for conscious activity, but the possibility - raised by Immanuel Kant - of initiating a totally new causal chain in the world, besides probably being an illusion, is not an essential ingredient of the concept of consciousness.

    The effect of conscious activity on the body (and vice-versa) cannot be explained in terms of Aristotelian “efficient causation” (since it violates the “causal closure” of the world, as pointed by Jaegwon Kim – see link below), but can be understood in terms of “formal causation”, in the sense that the form of body activity can affect the form of conscious activity, and the form of conscious activity can affect the form of body activity.

    Marcel M. Lambrechts · Centre d'Ecologie Fonctionnelle et Evolutive, Montpellier, France

    Dear Carlos,

    The senses (color, taste, smell, sound....) involve the environment, or not?

    Consciousness involves a response to an environmental change?

  • What is the difference in wideband specrum sensing and cooperative spectrum sensing for cognitive radios?

    I want to know the difference between wideband and cooperative spectrum sensing methods in cognitive radios.

    Regan Dhaksnamurthy · Sri Balaji Chockalingam Engineering College

    Thanks to all..!!

  • What is the innovations in traffic data collection and analysis?

    As all of us know that data is a very important while dealing with traffic engineering

     What is the innovations in traffic data collection and analysis?

  • Lawrence Uebbing added an answer in Triggers:
    Is research being done on the 'Trigger Phenomena'?
    I am seeing an increasing number of stories in the media where schools are recommending against, or even prohibiting, the discussion of sensitive issues, such as depression, suicide, sexual molestation, PTSD,etc, because discussing the subject may 'trigger' a negative response in those with experiences with the subjects. I find this trend disturbing. I am not aware that such a phenomena exists based solely on discussions (I am aware of some responses by those with PTSD to certain sounds or sights, but not discussions). This trend is stifiling in the schools open forums on very serious issues that young people need to be aware of and educated on. Is there any research done, or in progress, on the 'trigger phenomena'?
    Lawrence Uebbing · City University of New York - John Jay College of Criminal Justice

    Thank you Brittany, Maria and Remy. I have been unable to do any work lately but I did want to follow this up. The discussion of the Trigger Phenomena seems to arise during times of relative quiet but vanishes during very eventful times. To illustrate; I posted the original question at a time when there was not much discussion of campus rape. Recently the issue has exploded on campuses and in the media and I have not seen any reports that the focus on, and ongoing discussion of, campus rape has resulted in an increase in students suffering from anxiety or other debilitating disorders. If Trigger Phenomena is truly as powerful as some claim there should be a dramatic increase in reactions by affected students. Add to the rape discussions the other powerful issues of race and abuse of power by law enforcement that are currently being addressed on campuses, and there should be a very large increase in the number of students seeking help as a result of triggers. I am not seeing this. It would be a good time to do research on this and find out if the Trigger Phenomena exists as theorized. 

  • What are the best soft wares for primer design?

    Polymerase Chain Reaction is widely held as one of the most important inventions of the 20th century in molecular biology. Small amounts of the genetic material can now be amplified to be able to a identify, manipulate DNA, detect infectious organisms, including the viruses that cause AIDS, hepatitis, tuberculosis, detect genetic variations, including mutations, in human genes and numerous other tasks.

    Now I want to design primers for detection of cancer cells apoptosis by myself, and need help to guide me for a good soft ware. TQ

    Hüseyin DAŞ · Gümüshane Üniversitesi

    My favourite soft is Oligo 7.

  • Mita Brahma added an answer in Emerging Markets:
    What factors contribute SMES in emerging markets to adopt Innovation practices?

    Key Factors that are internal to firm or external to firm 

    Mita Brahma · Management Development Institute Gurgaon

    One key factor is definitely environmental dynamism: the frequency of changes, and intensity of changes. You could go through "The role of entrepreneurs in firm-level innovation: Joint effects of positive affect, creativity, and environmental dynamism" (Baron & Tang, 2011) for an overview.

  • How to draw ROC curve and RI curve for prediction generation using SVM?
    Will Rapidminer tool help me in drawing a ROC curve? Moreover, I tried installing it, but could not.
    Mohammad Faghihi · Payame Noor University

    how can i draw ROC in rapidminer?

  • Jiawei Zhang asked a question in Idrisi:
    Enhance the classification accuracy of habitat mapping with Idrisi Kilimajaro and assess the results properly?

    I am mapping the Peat areas where there are ambiguity in different habitats because of the highly similarity of vegetable classes.


  • Ravi Mehndiratta asked a question in PCR Analysis:
    Can anyone help in desigining primers for AGPase gene large subunit in wheat for real time pcr analysis ?

    Regarding primer desgining ...

  • Petr Mrak added an answer in Colorimetry:
    How to determine trace levels of soil available boron by colorimetry?

    Colorimetric determination of soil boron through Azomethine-H method is the most popular one. However, it's detection limit is not very low, as I guess. Can anyone suggest me any recent modification of the method so that I can determine the boron content of B-deficient soils?

    Petr Mrak · DOMA, Ltd.

    Dear Muhammad,

    The ICP-MS method, especially after a soil boron extract enrichment into organic phase (see e.g. Houba et al.) seems convenient and "sensitive" method for Berger-Truog hot-water soil extract. If this method is not available for you, maybe curcumine (rosocyanine mode) spectrophotometric method would be convenient. This method, however, is restricted by water concentration in reacting solution (maximaly pipetting volume of sample aliquot is 0.5 mL without evaporation this to dryness or without an acetanhdride addition e.g.). The absorbance value of rosocyanine-boron complex is approximately 0.065 for 0.1 ug of B in 0.5 mL of water aliquot, with cuvette thickness 1.0 cm  (i.e. 0.2 mg of B in kg soil for water: soil ratio 2:1 in Berger-Truog extract). By acetanhydride or propionanhydride addition, up to 2 mL of water aliquot (without the evaporation) it is possible to direct analyse.

    I wish you success in the boron determination and PF 2015.

    Best Regards,

    Karel FIALA, alias Petr MRAK

  • Juehui Shi added an answer in Statistical Programs:
    What is the best statistical program can be used for multivariate analysis?

    There are many statistical programs produced by software companies, enough to one should decide which software program is more fit to present and analyze the data. If we have data on ages of trees, size, growth rate, vitality, and seeds production. What is the best statistical program can be used for multivariate analysis for these parameters?

    Juehui Shi · University at Buffalo, The State University of New York

    Thank you Shuichi for sharing your experience.

  • What is the relation between DFT calculation and chemical action of that molecule in the human body as drug?

    What is the application of DFT calculation of a molecule in relation to medicinal chemistry? How can it influence in drug action? Is there any relation of them towards chemical action?

    Parasuraman P · Annamalai University

    Dear Eric B. J. Harris  and Alaa Salah

    thank u for the comments ..

  • How to draw animation using mathematical equation ?

    This  is  just  to  understand  how  to  make  various animation   in physics for  Physics Education.

    Gyan Chandra Chauthwani · Nuclear Power Corporation of India ltd.

    Well its a good question , but to answer this question completely which become a self contained is not possible in my view because animation is a big topic.

    But I will suggest you to use MATLAB , there is a book " Getting started with MATLAB" by Rudra Pratap  which contains a chapter on Graphics, it may help. Or you can use Mathworks original documents for it.

    I know its very superficial answer.

  • What is the best antifungal used in isolation of a mix of bacteria and fungi?

    I have some environmental samples that contain both fungi and bacteria and I want to isolate only bacteria

    What is the best way to do that and if I want to add antifungal in the media, what is the best and what is its optimum concentration?

    I will be thankful, if help with papers.

    Best Regards 

    Carlos Antonio Riera-Ruiz · Escuela Superior Politécnica del Litoral (ESPOL)

    I was in the same situation. In addition to the suggestions above you can check this paper in which they test Natamycin as fungicide to reduce the fungal charge on samples. 


    You can aso try to culture your samples con an incubator setup at 37˚C. 

  • Adam B Shapiro added an answer in Isoelectric Point:
    Amyloid Beta 29-40 and 29-42 solubility?

    Hello, I am looking for the best way to solubilize the Abeta fragments 29-40 and 29-42. The purpose is to use them for coating ELISA plates.

    I have already performed several ELISAs with other peptides (1-11, 12-28, 1-40, 1-42, etc.) and I haven´t found any problem using PBS pH 7,4 or Sodium carbonate-bicarbonate buffer pH 9,4. But I still have problems to solubilize these two fragments.

    1.- The isoelectric point for them is about 6, and the buffer has a pH 9,4, so this should not be a problem, isn´t it?

    2.- The fragments are strongly hydrophobic, do you think that DMSO could be a good option?

    3.- Could DMSO influence the ELISA results?

    4.- If I use PBS or DMSO for solubilize the fragments, should I use the same solvent as coating buffer, or it depends on the solubility at the coating concentration?

    From the supplier they told me that a basic pH should work fine with these fragments, but I have not seen that. Any suggestion? 


    Adam B Shapiro · AstraZeneca

    Amyloid beta 29-42 has no polar side chains (GAIIGLMVGGVVIA) so the pH probably won't make much difference to its solubility, except for affecting the charge on the N- and C-termini. This peptide will probably dissolve in DMSO, but it may not bind to the plates in 100% DMSO. Maybe you can make a concentrated stock solution in DMSO, then dilute it in buffer to a lower concentration that is soluble in the mixture of buffer and DMSO, with a low enough DMSO concentration that the peptide will bind, say 10% or less.

  • Stefan Joris Vermeulen asked a question in MFold:
    DG values in primerdesign are very important in order to prevent homodimerisation primerdimers etc. Now what would be a toleralble dG value?

    A critical step in primer design is the in silico analysis of yuor primer pairs and amplicon.

    A number of programs can therefore be used (eg mFOLD). On several fora there is a some debate about the acceptable dG values primers may have in order to be acceptable.

    Is there anybody who knows or did real wetlab studies in order to determine the accepatable cutoff  of theoretically found dGs?

    Some say that dG = -10 kcal/mol is still acceptable

    Others say a dG of =-2 kcal/mol is still acceptable

    Thanks in advance for any answer

  • Dr A. Kumar added an answer in Perovskites:
    Can anyone explain the negative conductivity of the materials?

    I am working on rare earth perovskites. When I measure the electrical conductivity (dc) of my samples at low temperatures (below room temperature) it is linearly increases (upto 1.0 S.cm-1@280K) with respect to temperature. After a particular temperature (Nearly RT), the material shows negative value of conductivity (i.e. -1.3 S.cm-1@RT) again it follows the same trend. Actually I don't know how to interpret this behavior. I have used Broad band Dielectric Spectrometer (BDS) Make:  NOVOCONTROL Technologies GmbH & Co. Model : Concept 80.  The temperature range is from 120 K to 473 K and the frequency range up to 5MHz.  So can anyone explain why I am suddenly getting negative values in conductivity at RT and above?  I am awaiting your valuable suggestions.


    Dr A. Kumar · Harcourt Butler Technological Institute

    Dear Satyamuthi,

    What is the status at room temperatute before cooling. Is it negative conductivity in the beginning or you get only after cooling? This is very important to understand your sign reversal at room temperature.

  • Mohsen Gholizadeh added an answer in Horses:
    Why i find a hight Linkage desilibrium in a breed horses (Arab-Barbe)?

    but this breed is created 14000 YEARS ago??

    Mohsen Gholizadeh · Sari Agricultural Sciences and Natural Resources University

    Finite population size is the key cause of linkage disequilibrium in livestock populations. LD in short distance is a function of Ne many generations ago while in long distance reflects the recent population history. you are offered to study an article by hayes et al. to find more!

  • What is the biggest scientific coincidence that you know?
    For me the two more important are:

    1. The phase transition liquid-solid for the water is that the solid state is less dense.
    2. The dielectric screening in metals is such that the Coulomb interaction among the electrons falls at a distance of the Bohr radius.

    The first one has many important applications as the one of allowing the live in rivers during winter or so on. On the other hand, there are also very interesting electric and thermodynamic phase transitions for this material

    The second, thanks to have a so local electric interaction it allows to have almost free electrons at quite high electronic density in matter and therefore to apply theories so useful as the bands in solids. Over all in metals
    Daniel Baldomir · University of Santiago de Compostela

       Sorry, the good link for going to the paper of Hawking is:


  • Joseph Kuhn added an answer in Universe:
    Will we ever meet our interstellar neighbours?

    Somewhere 'out there' in interstellar space are people like us, wondering if they are alone in the universe.

    Will we ever meet them or do the laws of physics prevent that ever happening?

    Joseph Kuhn · Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit

    Maybe they are already here, shocked about terrorism, hunger and war, and wondering whether there is intelligent life on earth or not?

  • What is dictionary learning and sparse repressentation using SVD?

    I need some study materials for the sparse coding, dictionary learning and KSVD in image denoising applications. Thanks in advance for reply. 

  • Glenn Watson added an answer in Optogenetics:
    Does anyone know the distance a certain optical light can diffuse in the brain issue?

    Hi, I am trying to use optogenetics to study the connection of two nucleus within rat brain. However, the distance between this two nucleus is only 1mm. Does anyone know the distance a certain optical light can diffuse in the brain issue? Thanks!

    Glenn Watson · Pennsylvania State University

    See the following article concerning light diffusion in different brain brain regions of mouse;


    See recent work by Ed Boyden's group as well addressing this issue;


  • Ahed Jumah Alkhatib added an answer in Spirituality:
    Can spirituality be expressed by animals?

    If so, are there any animal models?

    thanks in advance

    Ahed Jumah Alkhatib · Jordan University of Science and Technology

    Dear Carlos, 

    thanks for more elaboration. 

    I am still waiting for more responses from my colleagues.

  • How can I boost bridge solar inverter DC/DC block and DC/AC block output curve shape?

    For boost half bridge inverter application, if the input of module is non linear DC curve:

    * what type of curve in terminal of first block - is it half sine-wave each pi cycle?

    * the function of DC/AC bridge only changed the phase, is it the sine curve?

    Please see inverter diagram, attached.

    Pisupati Sadasiva Subramanyam · Vignana Bharathi Institute of Technology

    The Following two Articles will be helpful. The First one may clear your Doubts.

               Kiron Das et al., Vol.3, No.2, 2013

              Grid Connected Micro Inverter System Using Half Bridge Converter

               Kiron Das, Mirza Golam Rabbani

    This Article focuses a micro -inverter system connected to a grid. Past and present conditions of inverters are also focused. In this topology a dc -dc boost half bridge converter is connected to a low voltage PV side. A Pulse width modulated inverter is also integrate with this converter to supply synchronized current to the grid. An adopted Maximum power point tracking (MPPT) system is used to get maximum output.

    A highly nonlinear radiation and temperature dependent I-Vand P -V characteristic curve is shown in below

    The boost – half - Bridge converter is controlled by S1 and S2 with complementary duty cycle. Neglect all switching dead bands for simplifications.
    The idealized transformer operating waveforms are illustrated. When S1 is ON
    and S2 is OFF, vr1 equals to vc1 when S1 is OFF and S2 is ON, the voltage levels are unequal and opposite. At the steady state, the transformer volt -scond is always automatically balanced. In other words, the primary volt -second A1(positive Section) and A2 (negative section) are equal, so are the secondary volt -sec A3 (positive section) andA4 (negative section) are equal.

    The inverter output current iinv is pre filtered by a first - order low -pass filter on
    the sensing circuitry to eliminate the HF noises………..

    A boost half - bridge micro - inverter is presented in this paper. The operation principle is analyzed. Simulation result is shown to verify the circuit. The customized MPPT method is ensured that reliable operation of PV micro - inverter system. So it could be the model of the Distributed Generation system

    Link: http://www.ijrer.org/index.php/ijrer/article/viewFile/660/pdf

    2.  Grid-Connected Boost-Half-Bridge Photovoltaic Micro inverter System Using        

          Repetitive Current Control and Maximum Power Point Tracking  

          G.Krithiga#1 J.Sanjeevikumar#2 P.Senthilkumar#3 G.Manivannan#4
    novel boost-half-bridge micro inverter for grid-connected PV systems has been presented in this paper. Here plug in repetitive current controller was proposed. The boost half bridge dc-dc converter operation, principles and dynamics were analyzed.MPPT control method was developed. A 210W prototype model was developed and its simulation and experimental results were shown to verify the various principles.
    This circuit offers minimal use of semiconductor devices, simple circuit, easy to control and operate and also possess low cost and high reliability. The experimental results show high efficiency. The current which is injected to the grid is regulated. Under both heavy load and light load condition, it show low THD and high power factor.
    Finally, the customized MPPT method that generates a ramp-changed reference for the PV voltage
    regulation guarantees a correct and reliable operation of the PV microinverter system. By using variable
    step size, fast MPPT speed and a high MPPT efficiency can be obtained. As a result, the proposed
    boost-half-bridge PV microinverter system with its advanced control implementations will be a competitive candidate for grid-connected PV applications.

    Ink www.ijrcct.org/index.php/ojs/article/view/741/pdf