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  • Rainer Duesing added an answer in Motor Cortex:
    What are the commonly used electrode positions in 10-20 systems to acquire EEG related to primary motor cortex?

    I'm using a 16 channel EEG amplifier. In order for the initial studies what are the commonly used electrode position to grasp EEG related to Upper-Limb motions?  

    Rainer Duesing · Universität Osnabrück

    Dear Snajaya,

    for which infromation do you need a citation? The fact that the electrodes Jennifer mentioned are those closest to the central sulcus or that the signal you are measuring at this sites do not necessarily represent cortical activation directly under this electrodes?

  • What are the scaling issues for WRF model simulated energy fluxes and how finer grid size can be taken (<500 m?) specially over mountainous terrains ?

    I am using WRF model to simulate energy fluxes over the Himalayan region but I am facing different issues related to basic capability of WRF model over hilly catchments and its limitation to resolve the energy fluxes, where the terrain variation is very high.

    G. Bothun · University of Oregon

    The WRF model does not have the capability that you need to simulate these fluxes on scales smaller than the entire Himalayan basin.   The strong topographic variations essential introduce strong non-linear feed-backs to the energy fluxes, for instance, convection base fluxes will strong vary from valley to valley and topographic induces winds and lifting and micro-precipitation all cause large variations in place to place energy fluxes.  

    So what your trying to do is pretty difficult.

  • What is the best plasticizer for concrete self-compacting?

    I'm developing a mix for the production of lightweight self-compacting concrete.

    Andressa Fernanda Angelin · University of Campinas

    Hello Juan!
    Thanks for the advice!
    You have a viscosity controller to indicate or specify?

    Best regards,


  • Can it be considered that a Sulphate Resisting Portland Cement (SRC) is an artificial Portland cement (A.P.C.)?

    Saw that the SRC does not contain additions.

    Juan José Howland Albear · Instituto Superior Politécnico José Antonio Echeverría

    Normally the Portland cement for obtain a concrete resistent to the sulphate attacs is a normal Portland Cement with mineral addition (especially natural or artificial Pozzolans) to reduce specifically the C3A in the composition of the cement. The quantity of addition may be between 20 to 40% in weigh, depending of the porcentage of C3A. The pozzolans will react with the Calcium hidroxide in presence of water tu produced hidrated calcium silicates, similar to the reaction product of the Portland cement itself.

  • Stefano Quattrini added an answer in Particle:
    What if no more than 7 Poincare-group generators correlate with behavior of the Z and W bosons? Or, of the hypothetical graviton?

    A fuller statement of the question:

    What consequences arise (regarding nature or theories) if some of the 10 Poincare-group generators do not correlate with behavior of Z and W bosons, and/or (hypothetical) gravitons?


    I may have developed math sufficient to provide an analog for elementary particles to the periodic table for elements.  To the extent the resulting catalog of particles pertains to nature, it provides (for all 17 known ordinary-matter particles, some yet-to-be-found ordinary-matter particles, dark-matter particles, dark-energy particles, gravitons, and some other zero-mass bosons) spins, some information about interactions, some masses, numbers of generations (for fermions), and relevant numbers of generators related to the Poincare group (and special relativity).


    • The following particles would correlate with all 10 generators of the Poincare group: leptons, photons, the Higgs boson, and composite (yes, not elementary) particles such as pions and protons.
    • The following particles world correlate with 7 generators of the Poincare group: Z boson, W bosons, graviton, and some other zero-mass bosons.
    • The following particles would correlate with symmetries other than those discussed above: quarks, gluons, and some other particles.

    Parallel question:

    To what extent would the above findings violate known experimental or observational data?


    "Theory of Particles plus the Cosmos," especially table 2.8.2 in section 2.8.  (See attachment.)

    Stefano Quattrini · Ordine degli ingegneri della provincia di Ancona


    according to Noether:

    "The symmetry group of special relativity, the Poincar´e group, is a Lie subgroup of the group of general coordinate transformations. It has a finite number (7) of independent infinitesimal generators"

  • Louis Brassard added an answer in Cognitive Systems:
    Is Chalmers' so-called "hard problem" in consciousness real?

    In his 2014 book "Consciousness and the Brain: Deciphering How the Brain Codes Our Thoughts" Stanislas Dehaene wrote "Chalmers, a philosopher of the University of Arizona, is famous for introducing a distinction between the easy and the hard problems. The easy problem of consciousness, he argues, consists in explaining the many functions of the brain: how do we recognize a face, a word, or a landscape? How do we extract information form the senses and use it to guide our behavior? How do we generate sentences to describe what we feel?

    “Although all these questions are associated with consciousness,” Chalmers argues, “they all concern the objective mechanisms of the cognitive system, and consequently, we have every reason to expect that continued work in cognitive psychology and neuroscience will answer them. By contrast the hard problem is the “question of how physical processes in the brain give rise to subjective experience … the way things feel for the subject. When we see for example, we experience visual sensations, such as that of vivid blue. Or think of the ineffable sound of a distant oboe, the agony of an intense pain, the sparkle of happiness or the meditative quality of a moment lost in thought … It is these phenomena that poses the real mystery of the mind”."

    Stanislas Dehaene's opinion is "that Chalmers swapped the labels: it is the “easy” problem that is hard, while the “hard” problem just seems hard because it engages ill-defined intuitions. Once our intuition is educated by cognitive neuroscience and computer simulations, Chalmers’ “hard problem” will evaporate".

    Personally, I agree with Stanislas Dehaene's opinion.


    ''We can not have clear notion of consciousness without ... ''

    What are the type of things in the world we can have clear notion of?  Models or clear notions allow us to clarify aspect of the world but they are not things in the world like consciousness is.  Consciousness is not a notion in your head, it is what you are and so it exists , it allow you to have clear notions of many things.  Knowledge is information, about pattern in the world , relation, consciousness is not of this nature although it only exist for certain entities, it is never desimbodied.

  • Muhammad Maqsood Alam added an answer in Agarose:
    What is in your opinion the proper agarose% - volts/cm for separation of aprox. 1500bp in gel electrophoresis?

    I want to separate relatively close bands (difference of aprox. 50bp) for isolating each single band by cutting them from the gel to send them to sequence. Any advice would be appreciated.

    Muhammad Maqsood Alam · Quaid-i-Azam University

    yes, of-course , for it you use just 0.7 - 0.8% agarose gel,,,.

  • Which enzymes are responsible for heavy metal detoxification process in different bivlaves groups?

    Metallothionein is one of such enzyme.

    Shankhadeep Chakraborty · Techno India

    Thank you all.

  • Daniele Rogano added an answer in MODIS:
    Any suggestions on image processing for vegetation detection using NDVI technique?

    I have a MODIS 250m resolution satellite image in jpg format.How do i do image processing using NDVI technique on it? Basically i have to detect vegetation for a 250m resolution MODIS image using NDVI technique.

    We get a preprocessed NDVI image from MODIS but i had randomly taken a 250m resolution image from its image gallery.

    Daniele Rogano · Università della Calabria

    Hi, you should at first use at least 2 image files, NDVI requires two spectral bands for computation, one visible red and one near infrared.

    Then you can use a GIS (like ArcGIS) to compute files with NDVI technique.

    (try at http://resources.arcgis.com/en/help/main/10.1/index.html#//009t00000052000000)

  • G. Bothun added an answer in Exoplanets:
    Do any set of exoplanets arround any star follow the Titius-Bode law?

    Could anyone of you answer me please: Do any set of exoplanets arround any star follow the Titius-Bode law as far as we know?
    Thank you in advance.

    G. Bothun · University of Oregon

    The Titus-Bode law likely represents some kind of tidal/gravitational resonance involving various zones of accretion.   I would suspect this to be relatively Universal and "missing planets" are likely the result of processes similar to that which produced the asteroid belt in our Solar system.

  • How easy is it to detect a difference in protein composition using proteomics alone?

    A hypothetical question. I have two closely related plants. One is suspected to lack a certain protein present in the other. How difficult is it to discover this difference in the following situations:

    A.) I know the exact amino acid sequence of the protein that should be lacking 

    B.) I have no idea which protein is lacking, I do not know its sequence

    The task needs to be completed without the use of transcriptome or DNA analysis, only by the means of proteomics (Mass spectometry, Protein Electrophoresis, Western blot e.t.c) 

    Which methods should I use? How reliable are they? How long will it take? 

    In what case will this task be the most difficult to accomplish? 

    Vikram Narayan · University of California, San Francisco

    if you have a good antibody to the protein, western blotting should be sufficient to give you the answer you're looking for.

    Mass spectrometry should work too, if you know the sequence of the protein - all you have to do is look for the presence or absence of unique peptides.

    For case B - this seems very random; I'm not sure what exactly you mean. Does the protein exist at all (i.e. is it in databases / ORF translations) or are you merely speculating? If your protein is in standard databases like UniProt (even if there is no experimental evidence that the protein exists), you can use mass spectrometry to tell you if it is absent in your sample relative to another sample. 

  • Should a Disaster Medicine be part of Curriculum in Medical Schools ?

    Should Disaster Medicine be part of Curriculum in  Medical  Schools ?

    Arik Eisenkraft · The Faculty of Medicine, The Hebrew University, Jerusalem, Israel

    Dear Ishag,

    Disaster Medicine is an entity of its own in medicine, and should be part, in my eyes, of every medical school curriculum. At least in Israel it is. I guess only those who had to face mass casualty situations can really appreciate it.

    You cannot handle it successfully unless you are well prepared, in terms of organizing your medical and non-medical teams, logistics (medical and non-medical), infra-structure (water supply, electricity etc.), media, and international collaboration.

    There are some basic rules, kind of a generic check list, for basic response. On top of it, you should have different and specific response plans for different disaster scenarios that add to the basic generic plan, enabling you maximal flexibility when facing an un-expected disaster.

    You must also be familiar with other relevant first response organizations. If the police don't know what to expect from the fire brigades or from the emergency medical teams, the situation may become chaotic even more.

    This is only a brief overview of the subject. It is being taught in Israel both in Medical Schools and in the hospitals, as part of our home-front preparedness.

    So disaster medicine is not only about medicine, but also about every other relevant organization that has a role in disaster response.

    Once you are prepared, you will be able to improvise well. I know this sounds weird, but the truth is that you are never fully prepared to an event, there are always surprises, and only if you plan and train/exercise, and have the right equipment, you will be able to tackle well with an event.

    Arik Eisenkraft

    Jerusalem, Israel

  • How can I model volatility in an ECM?

    I am currently trying to estimate the effect of energy crises on food prices. Given the link between energy and food prices, I am inclined to reason that ECM will be best to estimate the relationship between food price and energy price (fuel price). Additionally I would like to include dummy variables in the model to estimate the effects of periods of energy crises on food prices. This I know is simple to do.
    Where am confused is, how to model price volatility in the context of an ECM. I am only interested in the direction where fuel price, as well as the structural dummies for energy crises influences not just the determination of food price, but their volatility as well.

    Muhammad Zahid Naeem · Universiti Brunei Darussalam

    I would also suggest you for a GARCH model with ECM terms included in the model. It will provide you better control over your analysis.

  • Maha Adel Elbadry added an answer in Taqman:
    What is the concern about using Taqman in PCR mutiplex?

    What is the maximum probes could be used by Taqman PCR mutiplex? What is the advantage and disadvatage of using Taq man PCR multiplex? I have ten different genes in human DNA need to be quantified by qPCR and I have about 24 samples, so I need faster method help to do that.

    Maha Adel Elbadry · University of Florida

    I agree with Joshen,

    The most I've seen in publications were four, and usually for viruses since they have smaller genoms. However it is highly unrecommended to conduct qPCR using multiplex.

    The competition among amplification can detrimentally affect your results. You may need to work separately first on optimizing a standard curve for each gene depending on its copy number in the human genom.

  • What is the problem of these pepper??


    I hope you have a good time

    i wonder if someone could diagnose the problem of pepper. These fruits was divided into two pieces and there was no pest. 

    please help me. 

    Franci Aco Celar · University of Ljubljana

    Elaheh, do know the soil characteristics? Boron deficiency made worst by:
    sandy soils, alkaline soils, soils low in organic matter, high levels of nitrogen and high levels of calcium. Have you noticed there are other symptoms?? With severe boron deficiency, the growing points of main shoot and laterals die. The younger leaves remain small, are curled inwards and deformed. They show chlorotic spots between the veins which are yellow to orange and the veins themselves can become yellow or purple. The older leaves appear yellowish green.

  • Paweł Jóźków added an answer in Vitamin D:
    Can you please suggest information on the evaluation of vitamin D in seminal plasma?

    I wonder which metabolites and at what concentrations I can expect.

    Paweł Jóźków · Akademia Wychowania Fizycznego we Wrocławiu

    Dear Professor Travnik,

    Thank you very much for the answer! I am especially curious if concentrations of 1,25(OH)D3 in seminal plasma and serum are comparable. I cannot find any reference for this...

    With very kind regards,

    Pawel Jozkow 

  • Svetla Maneva added an answer in Remote Sensing:
    Can some one to give me explanation of what some of the vegetation indeces (such as NDVI, PVI, CARI, SR) estimate in a plant?

    On the base of leaves reflectance data obtained by remote sensing method I calculate several vegetation indices (VI), which I found out in literature. Unfortunately no one of authors comments what the differences in the obtained indices  of control and infected plants presents.

    Svetla Maneva · Plant Protection Institute

    I have data produced by remote sensing applied to healthy plants and to plants infected by different viruses. I know yet that the healthy plants has lower spectral characteristics in green area and know the biological explanation of this. Sum of the viruses keep it spectral characteristic higher than the healthy one other have lower in NIR area - I still have not found explanation of this.I calculated many VI which I have found in literature. But in all articles I have read, authors just say - this index increases other decreases compare to control. I would like to know - if I could estimate how much the chlorophyll decreases on the base of how much he index increases. NDVI index shows decrease of chlorophyll - I saw many articles about this. I would like to know which of the other indexes preset changes in othe physiological or other parameters of the plants growth. For me is very important to enrich my conclusions for the healthy status of observed plants.

    Thank you to all of you that answeredme

  • How to make in GIS software (Quantum GIS or ArcGIS) parallels and meridians appear on the extreme limits of a polygon?
    Does anyone know how to make in GIS software (Quantum GIS or ArcGIS) parallels and meridians appear on the extreme limits of a polygon?
    I was on the sidelines latitude and longitude. How to make the GIS program to appear?
    I will put a photo so you know what I want to do.
    Gabriela Osaci-Costache · University of Bucharest


    In QGIS (2.8.1. Wien): New Print Composer > Item properties > Grids > Draw grid > Grid tipe: Frame and annotations only > CRS (the desired system, with long/lat) > Grid frame: exterior ticks > Draw coordinates > Format: degree, minute, second aligned > Left and Right: vertical ascending > Coordinate precision=0 > Frame: yes.


  • Muhammad Zahid Naeem added an answer in ARCH:
    Is it wise to run the ARCH(p) - GARCH(p,q) model, once the LM test for ARCH has failed to reject Null Hypothesis?

    i.e. the time series does not have ARCH effect

    My experiment is leading to acceptance of Null Hypothesis,Making it difficult to proceed further.

    Muhammad Zahid Naeem · Universiti Brunei Darussalam

    It is highly unlikely to defend a goal when you don't have a goalkeeper, similarly without finding enough evidence for the presence of ARCH effects, running any ARCH- GARCH models will not be conclusive. Therefore, It will be appropriate to correct the base model first for any improvements as pointed out in the above comment.

  • Kenneth L. Schepler added an answer in PRIME:
    How can I determine the position of the focal plane of a laser experimentally?

    There was no instrument like PRIMES FocusMonitor in the laboratory. Some experience was like marking spots on the surface of steel plate. When the mark is smallest, we think the position is zero defocusing. I wonder whether there is good method to determine the focal position accurately? The laser source was used for welding like IPG YLS-10000 in my laboratory.

    Kenneth L. Schepler · University of Central Florida

    Interesting discussion.  I immediately recalled my use of razor blades scanned across the beam to measure beam quality and spot size.  But I typically work with watt-level beams, not kW-class lasers.  Obviously, my poor razor blade wouldn't stand a chance in your laser beam.  Use of multiple attenuator/splitters and re-imaging would allow you to measure beam quality and even beam profile with a camera.  But attenuating such high powers can lead to unwanted beam distortions induced by heating of the attenuators/splitters and focusing lenses so one must be very careful.  However, since you only want to know where the focus plane is, Dr Hoffman's simple but elegant solution should work well.

  • Can anybody suggest a transcriptional promoter sequence active in Agrobacterium tumefaciens, other than Nopaline synthase promoter?

    For testing the expression of a protein in Agrobacterium tumefaciens cells, I would like to replace a common 35S::GUS cassette with another carrying an agrobacterium-specific promoter. NOS promoter is already in the vector for the NPTII expression, thus I am looking for a different one. Any suggestions? Thank you in advance for your kind support. Fabrizio

    No First Name Sudarsono · Bogor Agricultural University

    I can only guess that the bacterial promoters, integrated in the T-DNA part of the Ti-plasmid, will be able to drive expression of a transcription unit in the bacterial cells. Unlike the plant genome, there should be no positional effects associated with where the promoter (or a gene) is integrated in bacterial plasmid (or chromosome). You can always try doing it your self or googling for it in the internet. Good luck...

  • I'm looking for a well-known site for creating online questionnaires?

    I'd really appreciate any suggestions

    Lili Luo · San Jose State University

    Qualtrics, Survey Gizmo

  • Mushtaq Ahmad added an answer in Chitosan:
    How can I radio label chitosan microparticles, preferably without using its amine groups?

    I would like to label my chitosan particles radioactively, any thoughts on that? Thank you very much.

    Mushtaq Ahmad · Pakistan Atomic Energy Commission

    68Ga-NOTA-CHSg and 99mTc-CHSg Labeled Microspheres for Lung Perfusion and Liver Radio microspheres Therapy Planning

    Alejandro Amor-Coarasa et al., Hindawi Publishing Corporation. International Journal of Molecular Imaging. Volume 2013, Article ID 279872, 9 pages http://dx.doi.org/10.1155/2013/279872

    An emulsion method was used to create 30.1 ± 4.8 micro-m size range microspheres with biodegradable Chitosan glycol (CHSg).Microspheres were characterized and labeled with 99mTc or 68Ga as an alternative to MAA in perfusion PET and SPECT studies. Surface decoration of CHSg microspheres with p-SCN-Bn-NOTA was performed to increase 68Ga in vivo stability. 99mTc was labeled directly to the CHSg microspheres.

    I think CHSg microspheres with p-SCN-Bn-NOTA can also be used for indirect labeling of Tc-99m

  • When it comes to simultaneity is Einstein correct or is Dingle correct?

    Albert Einstein claimed in 1905 that a single event can occur simultaneously at different times within two inertial reference frames moving relative to one another. In 1950 Herbert Dingle argued that different times cannot be simultaneous. I have analysed this conflict by deriving the Lorentz equations using both points of view. According to this analysis Dingle must be correct. See youtube presentation of this analysis at  https://youtu.be/4XLYzhHQ64Y

    Valentin Danci · Science

    Charles Francis (Jesus College, Cambridge) wrote: "You have shown a diagram and given an clear explanation of how you assume your conclusion. To call it either a calculation or a proof, you would have to be unbelievably dense."

    Your idol Einstein made a similar assumption with even less proof. In his own words: "the two clocks synchronize if tB − tA = t'A − tB. We assume that this definition of synchronism is free from contradictions, and possible for any number of points"

    He never did a real experiment to prove his wrong assumption, which is now your religious belief.

    And my explanation was even more detailed than his. So you got to be totally incompetent in any discipline if you can't understand when two thought experiments are identical in reasoning and very similar in settings.

  • Vishal Patil added an answer in Plant Genetics:
    What is proper method of crushing the leaf tissue during gDNA isolation?

    should I grind it in only one direction i.e. clockwise or anticlockwise?

    Vishal Patil · Orissa University of Agriculture & Technology

    what is the importance of grinding direction?

  • Selvakumar . GP added an answer in FPLC:
    Is the minimum concentration of protein to be loaded in FPLC sephacryl s-200 column?

    I get very small peaks if I load 0.3 microgram (total concentration)

    Selvakumar . GP · Annamalai University

    3mg/milliliter, its not enough to get much higher peak, if u need higher peak u should increase your protein concentration level from 3mg/milliliter to 15mg/milliliter. Here i also attached some other document that may be useful to you.

    Sephacryl S-200 HR
    Column: BP 113/120 packed with Sephacryl S-200 HR, bed height 100 cm
    Sample: Albumin fraction from previous ion exchange step. Sample load
    equivalent to 4% of Vt (Vt = column volume).

    Sample concentration: 15 mg/ml

    Buffer: 0.05 M Tris-HCl, 0.15 M NaCl, pH 7.5
    Flow rate: 7.5 cm/h

  • How can I optimize the cost of a photo voltaic power plant?

    Overall cost using any optimization technique.

  • Mumtaz Danish added an answer in Cobalt:
    What are the possible products of the reaction between cobalt(II)acetate tetrahydrate and hydrogen peroxide?

    What are the possible products of the reaction between cobalt(II)acetate tetrahydrate (dissolved in extra pure methanol) and 30% hydrogen peroxide? The reaction results in dark green solution, which when left for evaporation results in dark green crystals.

    I am curious to know the chemical composition of the resulting crystals. Is it cobalt(III) acetate or something else? If these crystal are redissolved in glacial acetic acid what would result? 

    Mumtaz Danish · University of Karachi

    I am highly grateful to both of you for your valuable expert comments. A few more question in my mind are:

    1- As Mr. Toth indicated the oxidation of Co(II) with hydrogen peroxide takes place in MeOH at room temperature as is apparent from an instantaneous colour change from pink to dark green. If the resulting dark green crystals are dissolved in glacial acetic acid, will it convert to Co(III) acetate?

    2- Practical observation is, when these crystals are redissolved in acetic acid, and the resulting solution is left for evaporation, a sticky mass results which on complete drying changes into a sort of amorphous solid. Is this Co(III) acetate?  

    3- IF MeOH is replaced with glacial acetic acid as reaction medium, can we obtain Co(III) acetate directly?

    4- Will the hydroxyl radical, as result of homolytic cleavage of hydrogen peroxide, also attack the methyl group of acetic acid?

    5- Can the possibility of attack by hydroxyl radical be minimized with the very slow drop wise addition of hydrogen peroxide?

    6- Will temperature play any role in suppressing the attack by hydroxyl radical?  

  • Karim Ndeffo added an answer in Cross-Validation:
    Do you find it useful to do cross validation on very large samples?

    I have more than a thousand observations and I'm wondering if cross-validation would be efficient to perform with such a large sample as It can be very time-consuming...

    Karim Ndeffo · Université Libre de Bruxelles

    Well, the observations are obtained through Monte carlo simulations using discretized procesed of interest rates.

    I have more than a thousand observations.

    The utlimate goal is to assess what risk factors significantly impact a balance sheet.

  • Yacine Halouane asked a question in FLUENT:
    Gas mixture Fluent?

    how I can make a gas mixture in a closed cylinder (h2o+h2+o2), then I'll start the chimecal reaction combustion?