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  • Navita Nathani asked a question in Econometric Analysis:
    What are the test used for cross sectional data in econometrics?

    To make the data suitable for econometrics analysis some assumption tests are to be applied, which may or may not be used in time series data. please help in listing out those tests.

  • Zina Chaqmaqchee asked a question in Reflective Practice:
    What is meant by Double loop and Single loop?

    Can you please show the difference between them? it is related to reflective practice.

  • Prof. Shashikant S. Udikeri added an answer in Pesticide Resistance:
    Old insect colonies have other use than pesticide resistance studies?

    What is your opinion about old insect colonies without introduction of individuals from the field for a long time ago, what applicability may have these? I know that are used as controls in studies of pesticides resistance, but there are another uses?

    Prof. Shashikant S. Udikeri

    Such strains are very precious in every sense. It could be toxicological or resistance studies, evolution, genology,molecular basis etc.

  • Subhradip Karmakar added an answer in Bradford Assay:
    Any way to increase the protein concentration without using kits?

    I have expressed my gene into e.coli and done experiment based on the NEB pMAL Protein Expression. My protein is a MBP. I have done the cell lysis(freeze and thaw) and affirnity chromatography using amylose resin to get my purified protein. Just saw my SDS PAGE result from cell lysis that the protein is still there and band of my interested protein we expressed. When I tried for Western Blotting, the band of my protein didn't appear. Addition to that, I tried checking the concentration of protein using Bradford assay as none of my sample shown me a positive result. It is as if all my protein gone lost after the purification or the concentration is too low after purification. My target is to find out the concentration of purified protein of my interest. So, any way to increase my concentration? Kit or not using kits but preferably traditional way. Will precipitation would be a good idea?

    Subhradip Karmakar

    Accepted that your cloning is OK, you can use centristar (centrifuge based) concentraters to enrich your proteins. Your results seems a little strange though that you are unable to see any protein inspite the fact that you used a protein expression system.

  • Stephan T. Kiessig added an answer in ELISA:
    Tips for Coating ELISA plate with antibodies?
    I am developing an sandwich ELISA, for that I need to coat antibodies on plate. I need your suggestions about coating buffer, dilution factor, and blocking buffer. Someone told me you need a competitive protein to block. Can I use FCS for blocking?? Currently I am thinking to dilute and coat in PBS.
    Stephan T. Kiessig

    Hi Christopher,

    be careful with NaN3. It's a highly potent inhibitor of the peroxidase. If the plates are stored frozen, no anti-microbiological agent is required. 

  • Anshul Faye added an answer in Finite Element Analysis:
    UMAT ABAQUS: Structural Relaxation implementation..?

    I am trying to simulate a molding process of glass:

    I have implemented the standard Burgers model into UMAT abaqus. I have defined both Stress(DSTRES) and Tangent Modulus (DDSDDE) equations.

    In Step 1: I have fixed the lower mold and displacement for the upper mold was applied (ramp over time). Simulation is working good and successful.(PFA)

    In Step 2: Here i am not sure about the values for Tangent modulus and Stress. I have read in a paper about Prony series.. 

    Do any of you have a sample UMAT code for prony series on how it should be implemented to the calculated stress in STEP 1.

    Anshul Faye

    Sachin, I don't know if material properties can be changed from step to step, never came across such problem. Please check the manual.

  • Vitali Voblyi added an answer in Graphite:
    What is the young's modulus and poisson ratio of Graphite like carbon (GLC) material?

    Please suggest some research article which provides young's modulus and poisson ratio of Graphite like carbon (GLC) materials

    Vitali Voblyi
    I give full text my paper "Enumeration of labeled geodetic planar graphs"
  • Karasira Aimable asked a question in Multimedia Systems:
    How could blind, deaf and mute get access to multimedia systems?

    sign language


  • Linda Molla added an answer in Crosslinking:
    What concentration of formaldehyde should I use to crosslink nuclei after isolation in order to do ChIP?

    I need to perform ChIP on isolated nuclei, but i don't know if I should use 1% formaldehyde or if I should decrease the crosslinker concentration?

    Linda Molla

    Dear Jean-Clément,

    I was wondering about doing the same, isolating nuclei and then doing Chip. The reason is that my protein is also abundant in cytoplasm and I would prefer enriching the nuclei and then cross linking. I am curious to know what your findings where and whether you would recommend crosslinking just the nuclei.

  • Tara Goddard added an answer in Transportation Engineering:
    Where can I get design guidelines in making a community or within CBD a non-motorization transport user-friendly?

    I need it for my literature review for planning strategies in implementing non-motorization as a sustainable transport? I only have one and is published way back 1995 by the Florida Department of Transportation.

    Tara Goddard

    If you are looking for guidance documents, I would start with the NACTO Urban Bikeway Design Guide and the Urban Street Design Guide. You can explore that site to find references to peer-reviewed journal articles on many aspects of non-motorized transportation. There is also the CROW out of the Netherlands, considered one of the first and best bike traffic guidance documents. I hope this helps!

    + 2 more attachments

  • Wenfang Xie added an answer in Plaque Assay:
    When doing plaque assay,why do vero cells tend to shed from the plates after Sendai virus inoculation?

    Currently.I am doing plaque assay on vero cell to detect the virus titer of lung homogenate from Sendai Virus infected mouse.The vero cell on the 6-well plate looks good before infection. But after inoculated with 200ul lung homogenate and incubated for 15min, the vero cells tend to shed from the plate, and the less dilution the worse(please see the picture attached).On the contrary, the mock well looks good. As the shedding is so serious and sometimes it is hard for me to calculate number of the plaques accurately.I wonder why this phenomenon happen? How to solve this problem?

    Wenfang Xie

    Hi Nathalie, I don't think the temperature of the agarose would be the problem.Because I noticed the cells detach from the plate before placing the agarose layer. I guess I've solved the problem, not that perfect though as some of the  cell layers are still not intact.  I did several serial dilutions for the each sample and get an average titration. For example, assuming the real titer for sample A is 2*10^3 PFU/ml,  I did 1:10 ,1:100 .1:1000 dilution, then I probably get   186, 17,  1 plaques in those different dilutions respectively. So the range of the titration would be somewhere between 1*10^3-1.9*10^3. So in this case I believe 186 and 17 would make more sense so I will present the final titration as 1.8*10^3 PFU/ml (the average of 1.86*10^3 and 1.7*10^3 and just ignore the third dilution).Anyway, I think the deviation is acceptable.

  • Karasira Aimable asked a question in Multimedia Systems:
    How could persons with disabilities get access to multimedia systems?


    human computer interaction

  • Demian Arturo Herrera Morban added an answer in Nephrotic Syndrome:
    How can we measure appropriate weight of a child with nephrotic syndrome whose previous weight is not recorded ?

    During  disease process patient gain weight  hugely.  So if we treat according to current weight then there may be  a chance of steroid toxicity. 

    Demian Arturo Herrera Morban
    There are some formulas regarding the level of edema and the weight to recalculate the current weight, but i dont think that on severe forms are very accurate.
  • Claes Richard Fredö added an answer in Turbine:
    Can Damping-Half power bandwidth method be applied to continuous signals?


    I am writing about the determination of the damping with a half power bandwidth method. I know that this method is based on short pulsed excitation like impact hammer or similar, where I have an input and an output of signal.  In my case I just have an output signal and my input signal is unknown. I would like to know if this method also can be applied to continuous signals. I mean a signal (vibration spectrum) which is excited on a rotor blade by the air in a turbine. I know that I can applied it, but I need a guideline or a norm for it.

    Thanks for your reply.

    Claes Richard Fredö

    Hi Semsudin

    The half power bandwith may work if your machine changes speed as your sinetone then sweep up/down in frequency.

    Most machines do not run perfectly and there is some degree of random excitation. If you can see your resonance, albeit at low amplitude, you might be able to estimate damping as well.

    Than, if the object of interest is accessible for bumptest during operation, you can do so if you provide stronger excitation than normal operation.

    A rotating system might be able to 'bump' internal resonance if you can give it a sudden load step.


  • Mayuri Bapat added an answer in Internet of Things:
    Can you suggest research topics in the field of IoT?

    I am from computer science backgroud having expertise in AI/Machine Learning and Data Science. I was wondering how my knowledge can be leveraged for research in IoT field.Thanks.

    Mayuri Bapat

    Hello Arindam,

    As you have knowledge of AI and Machine Learning ,I like to suggest you research  topic on IOT.

    "Implementation of IOT to avoid accidents".


  • Marcella Reilly asked a question in Prejudice:
    Psychology Study: Investigating the Implicit and Explicit measures of the Anti-Fat Bias on subjective ratings of Attractiveness?

    Hi everyone! I am conducting a small online study investigating the implicit and explicit measures of Anti-Fat Bias on subjective ratings of physical attractiveness. The main objective of the study is to compare the individual differences on implicit and explicit judgments of weight impacting subsequent ratings of physical attractiveness. The implicit measures will be collated by utilizing the "Harvard Take a Test" Implicit paradigm followed by explicit measures by use of The Crandall Anti-fat Questionnaire(Crandall, C.S. (1994). Prejudice against fat people: Ideology and Self-Interest, Journal of Personality and Social Psychology). 

    If you wish to take part please click on the link below and once you have gained access press onto the "Weight IAT". Once you have completed the procedure there will be a questionnaire that you will be able to fill out and can resend back to me at marcella.oreilly@ncirl.ie. 

    Many thanks! I would really appreciate your participation.  

    + 1 more attachment

  • Indra Kusuma added an answer in Fibroblast Culture:
    Is this an alkaline phosphatase positive for stem cells?

    We stain our fibroblast culture (designated for stem cell feeder cells) with AP, the results show a few red stained cells? is this a AP+ results or a false positive? is this means that there is a small stem cell population in our fibroblast culture?

    pic attached



    Indra Kusuma

    thank you Peggy..i will consider this kit...hope you solve your problem too

  • Sudarson S. Sinha added an answer in FRET:
    Would you tell me, how to match the probe to the quencher?

    Dear Community,

    I don't know on what basis people adapts its probe, a simple example: why does Trp quench the iodine, oxygen, caffeine and acrylamide, among others. Why does rhodamine quench the Trp?

  • Syed Asad Maqbool asked a question in Dielectric Constant:
    Dielectric constant from complex impedance spectroscopy??

    i have been performed complex impedance spectroscopy and want to know that how i can find dielectric constant (real and imaginary parts) from impedance data??... what is the method to find dielectric constant from impedance data?

  • Rajeev Dwivedi, Ph.D. added an answer in Balanced Scorecard:
    How to develop a collaborative balanced scorecard?

    When a group of stakeholders across sectors (public-private) they carry different interests. What are the key technical and organizational issues that affect building a BSCD

    Rajeev Dwivedi, Ph.D.

    make different different yardstick for different stakeholders. one BSC will not work with all. 

  • Mahboubeh Maribel Yazdanifar added an answer in Puromycin:
    Has anyone experience with TALL-104 (ATCC-CRL-11386) cells? How do they normally look like?

    We newly brought the cell line TALL-104 from ATCC. We would have expected that they grow as rounded-like cells in suspension. Like you can see only a few cells look like this. We are culturing the cells in the way ATCC is recommending: IMDM; 20% FCS; 50 U/ml IL2; 2.5 µg/ml human albumin; 0.5 µg/ml D-mannitol and Pen/Strep.; 37 °C, 5% CO2

    How does your TALL104 cells look like? Do they also produce a lot of cell crap? In which way could you optimize the culturing condition? How fast do your cells proliferate - what is the doubling time? What cell number is the best to maintain them (4x105 - 1x106 cells/ml  like ATCC recommends)?

    Do you have additional experience with transfecting them? What is the best way to transfect them and how much puromycin do they tolerate?

    Thanks a lot for sharing your experience 

    + 1 more attachment

    Mahboubeh Maribel Yazdanifar

    I tried R10 too and it doesn't seem to be doing any difference over a week. My cells are from ATCC (CRL-11386).

  • Amol Chintaman Badgujar added an answer in Band Gap:
    Is there a published work where an overall or effective thermal conductivity of CIGS can be found?

    Is there a published work where an overall or effective thermal conductivity of CIGS has been established or measured experimentally? By CIGS I mean CuIn(x)Ga(1-x)Se2 where x varies from 0 to 1. Of course, for different x's, the thermal conductivity is different. It concerns here a material with band gap 1.15 eV. So, I think it concerns x around 0.2.

    Amol Chintaman Badgujar

    Finding exact data for thermal conductivity of CIGS with varaiation of Ga compositin is difficult. But you can go through following reference which have used for laser ablation of CIGS thin films for scribing purpose.

    A. D. Compaan, I. Matulionis, and S. Nakade, Opt. Laser Eng. 34,15 (2000).

  • Pavol Jakubec added an answer in Colonialism:
    Under what conditions does a small power qualify as a great power ally or client?

    States, formally equal, enter into closer political, military or economic relations with each other. Partners frequently fall into different categories within hierarchy in terms of power, which tends to mirror in the relationship proper and its dynamics.

    If we are challenged to understand various small state position, what (kind of) constellation make an ally, junior partner, client or colony?

    Any suggestions about variables and cut-off levels?

    And, last but not least, research?

    Many thanks!

    Pavol Jakubec

    Dear all,

    Thank you for your responses. It is very interesting to see how different they can be. This is something what I especially value about ResearchGate: it channels both expertise and diversity of expertise.

    @Tony: Reasons why states decide for a change of their primary strategic partners were not in focus of my question, let alone any particular change. These reasons tend to be rather obvious. For example, Norway had a superbly close security relationship with Britain in 1945. By 1947 it has become evident that London is no longer capable of fullfiling the its former role (cf. Corelli Barnett´s work), the Norwegians simply redirected accross the Atlantic.

    @Kacper: So the whole thing is not about consensus, it´s about perceptions. I bet it is. There we get two sets of perceptions, since each partner has his own lens? Thanks for reminding me to ask about who is assessing.

    @Tom: Thanks for bringing dynamics and control mechanisms in! The case of Slovakia is, in my opinion, quite illustrative – although, I assume, one could still argue about nuances.

    @Mr. Treivish: Thanks! This sounds reasonable, but what about indicative levels

    @Mendee: Thank you for reviewing Mongolia´s case for me. (Btw., guys, I find it with a little irony that we discuss Mongolia, or Australia as small states here). So strategic value may outplay other resources and gain higher status for the smaller power to such an extent that it may be promoted from a client to an ally. – Btw., I remember that back in the early 1920 a Czech Communist served as Comintern delegate in Outer Mongolia. Shall check details, it´s been years now I read the book and I remember the name was maimed seriously.

    @Douglas: Here we are in the „perceptions road“ again. This seems very sound to me. Thanks for reminding me of „the power of the week“. Sure, there are quite many episodes in history when the junior partner succeded to „punch above its weight“ and secure gains.

    @Hans: Sure I know Snyder´s article, but it´s been a while and, I think, it´s high time to read it again. Thanks for directing me to your article. I definitely should browse JPR more often! As an Europeanist, I keep thinking about two small states regions that have experienced those Ianus-faced reality you indicate: Central Europe and Scandinavia.

    Many thanks, dear colleagues!

    All the best,


  • Tytravia Riley asked a question in Metarhizium:
    How do I grow Metarhizium anisopliae (met 52) granulated spores that I bought from a supplier?

    I also have the liquid form of Met 52 also that I brought from a local supplier. I just need help on figuring out: what protocol to use and what media to use. From the tons of papers that Ive read they talk about spore suspension but I can't get to that step if Im lost on how to first grow the spore/liquid on media. Thanks !

  • Anuruddha Jayasuriya asked a question in Reinforced Concrete:
    Is there a relationship between the water-cement ratio and the Interfacial Transition zone?

    I understand the fact that when water cement ratio increases, the concrete microstructure will have higher hydrated gel pores. In corrosion studies in reinforced concrete, the porous band has a major impact on the time to crack the cover concrete. However, many research articles claim that the average porous band is considered to be 10-20 micrometers. But it is definitely clear that this porous band of the concrete microstructure should vary with the W/C ratio.

    So, does it have a relationship with these two factors or is there anyway to approximate the porous band for known concrete proportions (Like for goven w/c)? If possible let me have some reading materials on this.

    Thanks to all who'd like to help me.

  • Igor Chybicki added an answer in Genetic Diversity:
    What is the difference between Genetic population structure and Genetic Diversity?

    is there a difference between Genetic population structure and Genetic Diversity?
    and what is the least number of samples can be taken for population structure?

    Igor Chybicki

    Just a comment: as mentioned, one useful way genetic structure can be defined is F-statistics. Fis and Fst can be seen as analogue measures, but at different levels of hierarchy, with Fst related to genes sampled within subpopulations relative to a population and Fis related to genes sample within individual genotypes relative to a subpopulation. Distribution of genes among individual genotypes can be random (no structure, HW conditions) or non-random (e.g. due to inbreeding or selection if possible) and Fis will inform about that. Genes can also be nonrandomly distributed among subpopulations (e.g. due to genetic drift) and Fst will inform about that. Thus, genetic structure can exist, quite independently, at different levels. However, genetic diversity (genetic variation) is a pre-requisite for that. There is no genetic structure if there is genetic variation. On the other hand, genetic diversity does not imply genetic structure by default...

  • Miguel Ortega added an answer in Geometry:
    Why is "congruent" but never "equal" used in geometry?

    I use these definitions:

    Equal               Magnitudes that are neither less than nor greater than each other

    Magnitudes are lengths of segments, radii of circles, measures of angles and areas of triangles.

    Congruent     Complicated figures with several characteristics and those that fully define the figures are equal, so we know they all are

    But my survey of extant geometry books indicates that the authors simply never use the word "equal" but have replaced it wholesale with the word "congruent."  This procedure could only be justified if there is something fundamentally different about geometric magnitudes than magnitudes used elsewhere in mathematics.  But what?  Those same textbooks routinely use numbers to measure lengths in meters and angles in degrees, and do so in the same way that physicists and others use numbers.  So why the different terminology for when lengths and angles are the same?

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: I propose to write a textbook on the subject of Euclidean geometry. It will be divided into two volumes, Geometry without Multiplication and Geometry with Multiplication. In the future I may write a third volume about solid geometry. Geometry without Multiplication ranks high school geometry students as follows: White Belt: Abstract Algebra Orange Belt: Triangle Congruence Green Belt: Quadrilaterals Red Belt: Quadrature Black Belt: Circles I have written the text for white- and orange-belt students and I have written an outline of the remaining textbook. I will update as I progress. I hope to receive comments on my proofs and on my organization of theorems from other geometers during the writing of this book. Why the martial arts analogy? We are under attack from the math haters. Asad Zaman writes: “It is a completely mistaken idea that scientific theory is based on deductions from a series of postulates – that is the description of the methodology of mathematics… There is no science which uses axioms and logical deductions to derive scientific theory. “Mathematics is not a ‘science’ since it is not based in any direct way on observational evidence. Unlike scientific laws, mathematical laws are not affirmed observational evidence. Recognition of the possibility that there are bodies of knowledge which are not science would lead to greater tolerance and pluralism which is currently desperately needed.” Tolerance? No. Such outrageous talk by the World Economics Association has brought war and discord to our once quiet study of triangles. If Asad Zaman were just some crazy man, it would not matter. But Zaman is the editor of the Real World Economics Review. He wields this terrifying power to no other end than to ban all mention of deductive logic. I alone stand in his path. If I falter, then geometry will be excluded from the high school curriculum and a whole generation will be taught only hate for deductive logic. Can you help me fight the Islamic extremists? Intimidating their enemies by cutting off heads and baffling them by slyly redefining dialectical materialism as “ontology” and historical materialism as “processual,” the Islamists and the Marxists have united to rid the world of geometry and to raise a generation of Westerners with only hate for deductive logic. Logic alone can defeat the haters!
      Full-text · Article · Jan 2016
    Miguel Ortega

    In my research, two objects are "congruent" when there is an isometry from one to the other, but they might be different in a strict definition as sets.

    For example, two triangles in a affine euclidean plane are congruent iff their sides have the same lengths. This means that there is a rigid movement of the affine euclidean plane carrying one triangle into the other. However, these triangles are different as subsets of the plane.

  • Alberto Vieira Borges added an answer in Global change biology:
    A North American, gridded database of annual temperature and precipitation data for global change biology study?

    A cry for help to any global change biologists or climate scientists:

    I am conducting my first-ever analysis of a long-term biological dataset from a wide geographic area in North America, and would like to include temperature and precipitation data in the analysis. Ideally, I would like to get annual average temperature and total annual precipitation data from ~350 specific sites in North America from 1970-2009. I have looked around a bit, but am unable to find exactly what I am looking for. Ideally, it would be a “gridded” database where I could input GPS coordinates and get annual precipitation and temperature data back to 1970. Does anything like this exist out there? Thanks! Paul

    Alberto Vieira Borges

    Hi Paul,

    Check out National Centers for Environmental Prediction (NCEP) products:




  • Thorsten Beuth asked a question in Calculations:
    How can the scattering phase function for I_x-I_y be higher than I_x+I_y?

    Hello community, I am messing up my brain by a very particular question. I am using Deirmedjians Calculation from 1969 ("Electromagnetic Scattering on Spherical Polydispersions") to calculate phase functions. But in his and my calculations the phase functions of P1 are exceeded by P2 to P4 several times. I am asking myself what this means since I thought that the phase function shows the fraction of scattered light towards a certain angle. In my understanding this would mean that e.g. a stoke vector of (1 1 0 0) would be scattered to reach (a b 0 0) with b>a. This does not make any sense from my point of view. So what do I misunderstand here?

  • Timofey Golubev added an answer in PDMS:
    Is there any significant difference between the film made from PMMA dissolved in chlorobenzene and that from PMMA dissolved in dichloromethane?

    I am attempting to use the process described in the link below. Briefly, one spin-coats PMMA onto the substrate that has nanostructures on it. Then put PDMS on top and add a few drops of water which is supposed to allow the PMMA to separate from the substrate. Then use PDMS as mechanical support to transfer to clean substrate. My initial substrate is SiO2 with some tape residue remaining from mechanical exfoliation. I want to transfer to clean SiO2.

    I am unable get the PMMA to separate from the substrate as a film. It resembles more like a paint which I can only scratch off. I suspect something is wrong with the PMMA solution. I use 950k 2% in chlorobenzene, something we already have in our lab.  The paper uses 3% in dichloromethane, but I was told it will not make a difference. I have tried different PMMA spin rates (1000-3000rpm) and annealing temperatures (50-80C) with no success.

    Any advice will be much appreciated

    Timofey Golubev

    Thank you Dr. Tsambani. I have already seen the data sheet. It allows me to estimate film thickness for chlorobenzene and anisole solutions that Microchem makes but not for other solvents. Clearly my film is too thin (.2-2micron) to be able to handle with tweezer, but I hope it can still made to float on top of water then transferred by switching out substrate underneath and lowering the water level. Do you know if there is any advantage of making our own PMMA solution with dichloromethane?