ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.

Browse by research topic to find out what others in your field are discussing.

Browse Topics

  • Abril Zubía added an answer in Economics:
    Do you have any good recent paper about Wagner's Law?

    I looking for recent works about the relationship between public spending and production in an economy. The idea is test the validity of Wagner's law. 

    Abril Zubía · Universidad Autónoma de Ciudad Juárez

    I think that Tony Payan Ph. D might know of this subject, mainly related on the walfare state.

    My best wishes.

  • Deepak Samuel Vijay Kumar added an answer in Marine Biodiversity:
    Can anyone help identify this specimen?

    We found this specimen on inter tidal zone In Persian Gulf.

    Deepak Samuel Vijay Kumar · National Centre For Sustainable Coastal Management

    I agree with Dr Shields.. Aplidium and it can even be Bortryllus because of the typical floral petal-like arrangement..



  • Yelchuri BSR Prasad added an answer in MCP:
    Is there any reason for asymmetry in Trans grating+MCP?

    In some of the experiments it is noticed that the transmitted grating x-ray spectra (TGS) recorded on a micro channel plate detector (MCP) looks asymmetric. Any possible reason for this? ( In this case the source is capillary discharge plasmas)

    Yelchuri BSR Prasad · Raja Ramanna Centre for Advanced Technology

    Thank you very much Dr Mallick for you prompt reply.

    1) I am attaching a typical spectrum from X-ray laser at ~46 nm (~25 eV) from the high voltage capillary discharge plasmas in the Argon gas. This laser is single shot , typically 1ns duration laser pulse.

    2) We send a >17-20 kA fast rise time current pulse with typically 40 - 50 ns rise times (10-90%) in Argon gas in a ceramic capillary of ~ 3 mm inner diameter.

    3) We also use a 20 A current pulse ( slowly decaying ) few micro sec  before the main current pulse to pre - ionize the Ar gas. The magnetic field and the force associated with main current pulse pushes / compresses the Argon plasma inwards forming 100-300 micron thin  plasma column (length is 15 cm), what we call as pinching. Thus the density and temperature of this plasma column is higher thus leading to laser generation.

    4)This 1 ns x-ray pulse is incident on a transmission grating to ascertain the wavelength of the laser (to confirm/show  whether it is 46.9 nm really). The 100 micron wide free standing grating consists of  gold wires at a density of 700 lines/mm ( corresponds to wire thickness of 0.7 micron, each separated by 0.7 micron). This diffracts the incident radiation/ monochromatic in this case to either side of zero'th order. We also have higher diffraction orders in addition to 1st order and since here we have intense low divergent radiation here, we are able to see upto 5th order ( in some cases we have seen up to  6/7th order).

    5) To record this diffraction spectrum we use micro channel plate detector coupled with a phosphor. The phosphor output in visible range is recorded using a simple CCD /digital SLR camera (550D Canon in present case).

    6) No sample is involved at this stage. Only characterization of generated radiation from Plasmas. (of course it happens to be coherent , short duration laser, but that is different matter).

    7) in the case of transmission grating the lnv.lin.disp factor is calculated from the grating parameter d,distance D between the grating and detector from which we calculated where a 46.9nm line should be seen from the zero'th axis.

    8) I was suspecting whether this is happening due to orientation angle of the MCP channels (micro channel) but even by rotating the mcp, nothing changed. In any case since MCP channels are both sides metallized it should not matter I think.

  • Jayakumar Renganathan added an answer in Trace Heavy Metals:
    What's the best and/or cheapest way to measure heavy metal (particularly lead, mercury and arsenic) concentrations in freshwater?

    I've read that Spectrophotometric Analysis would be a good method, but are there alternative ways of measuring heavy metal concentrations and how do you go about it? 

  • Nithiyanantham S added an answer in Waxes:
    How can I extract waxes from a rapeseed press cake?

    during the cold pressing of rapeseed oil a lot of waste is generated. I intend to extract waxes from a rapeseed cake sample. Can anyone suggest possible protocols in how I can extract wax from a sample. thanks

    Nithiyanantham S · Tierra Seed Science Pvt. Ltd.

    Please use hexane/petroleum ether solvents for complete removal of wax

  • Rajinder Gupta added an answer in Perl:
    How do I create a table that has HLA alleles from both tables in one column in Perl?

    I have outputs of assays (C1q by OneLambda and C3d by Immucor). They are Excel tables where column A is the list of HLA alleles and column B is the fluorescence value (numbers).

    Suppose they look like this:

    C1q output:


    HLA-A*02:01    |     324.5

    HLA-A*02:02    |     1035

    HLA-A*02:15    |      11


    C3d output:


    HLA-A*02:01    |     24

    HLA-A*02:02    |     0

    HLA-A*03:01    |      825


    I need to create a table like this:


    HLA-A*02:01    |     324.5   |      24

    HLA-A*02:02    |     1035    |       0

    HLA-A*02:15    |      11       |        n/a

    HLA-A*03:01    |        n/a    |        825


    I am very amateur in programing. To my knowledge, Excel won't do this. I tried to use Perl. I saved both tables as text files (input_c1q.txt and input_c3d.txt). I created a script that takes these files and stores them as hashes, where keys are HLA alleles and values are numbers. Now I am stuck, because I can't figure out how to combine them into a hash that has keys and values from both original hashes, AND how to get this printed or stored into an output file.

    This is probably a basic task, but I am struggling.

    Here is the script that I wrote so far:



    use warnings;

    #Create a hash containing C1q assay output

    %c1q = ();

    $inputc1q = "input_c1q.txt";

    open (FH, "<", $inputc1q) || die "Could not open file: $!\n";



    my($key, $mfi) = split("\t", $line);

    $c1q{$key} = [$mfi];


    close FH;

    #Create a hash containing C3d assay output

    %c3d = ();

    $inputc3d = "input_c3d.txt";

    open(FH, "<", $inputc3d) || die "Could not open file: $!\n";

    while ($line2=<FH>){


    my($key2, $mfi2) = split("\t", $line2);

    $c3d{$key2} = [$mfi2];


    close FH;

    "Trying to create a combined hash that contains both C1q and C3d outputs here (sort of works).

    foreach $x(keys%c1q){

    if (exists $c3d{$x}){

    $c3d{$x} = [$c3d{$x}, $c1q{$x}]}


    $c3d{$x} = $c1q{$x};}


    #Now I need to get it printed and can't get it to work


    print"$c3d{$x} = > [$c1q{x}]\n"}


    Any perl experts who can help?

    Rajinder Gupta · National Agri-Food Biotechnology Institute

    Hello Dulat

    I have tried to make a script for you; I hope it resolves your query

    It also takes into account the different number of entries in both the files


    use warnings;
    use strict;

    my (%map1, %map2);

    open my $fh1, '<', "C1q.txt" or die $!; ###1st input file
    if($_ =~ m/[A-Z]/i)
    my @temp1 = split ('\t', $_);
    $map1{$temp1[0]} = $temp1[1];

    open my $fh2, '<', "C3d.txt" or die $!; ###2nd input file
    if($_ =~ m/[A-Z]/i)
    my @temp2 = split ('\t', $_);
    if(exists $map1{$temp2[0]}) ###Comparing for similar ids
    my @array = ($map1{$temp2[0]}, $temp2[1]);
    $map2{$temp2[0]} = [@array]; ###Hash of arrays

    foreach my $key (keys %map2)
    print "$key\t";
    foreach (@{$map2{$key}})
    $_ =~ s/\r|\n|\t//g;
    print "$_\t";
    print "\n";

  • Ahsan Saleem asked a question in Cross Sectional Survey:
    Can we add 50% more sample size in cross sectional surveys? If yes! how can we justify it?

    With a prevalence of 11% the calculated sample size was 150. Can I add 50% sample size to enroll more respondents?

    If yes! how can we justify it?

    What are the conditions where we need 50% more sample size?

  • Sarang Sapre added an answer in Gels:
    About the pH of the stacking gel in SDS-PAGE

    It seems that the low pH (pH 6.8) in the gel is for the glycine in the running to exist as zwitterion to line up the samples before reaching the separating gel.

    Why the pH is 6.8 instead of 6? the isoelectric point of glycine is pH 6.07, doesn't a lower pH will be more suitable?

    Sarang Sapre · Junagadh Agricultural University

    The solubility of the molecule will be lowest at its isoelectric point. So there are chances that it will precipitate out.

  • Alev Kelleci added an answer in Differential Geometry:
    Can anyone give me information about $H^2 - K = c$ satisfying surfaces?

    In differential geometry: surfaces with $H^2 - K = 0$ (where $H$, $K$ are the mean and resp. Gaussian curvature) are well known - as umbilical surfaces. Is anything known about surfaces that satisfy $H^2 - K = c$ for an arbitrary constant $c$? Name? Characterization?

    Alev Kelleci · Firat University

    Dear Professor Magda,

    I am sending two papers as documents. I hope, they are useful for you. 


  • Bhushan Dabholkar asked a question in Reactor Design:
    How to prepare polyaluminium chloride commercially?

    polyaluminium chloride preparation , batch reactor design.

  • Roy M Kimble asked a question in Fetal Surgery:
    What does the future hold for fetal surgery?

    Fetal surgery has been around for decades, but clinically it can be argued, has not lived up with the expectations of the researchers from the 1980s and 1990s

  • Shiv Prakash added an answer in Blast2GO:
    What is the best method for gene ontology enrichment analysis in RNA-seq data for rice?

    What is an effective and user friendly method for GO enrichment analysis in RNA-seq data for rice? I saw some tools like AgriGO, Bingo, Blast2Go likewise, with little bioinformatics knowledge which is a easy tool to go for enrichment when the differentially expressed data-set is available for the wild type and the mutant?

  • Jayakumar Renganathan added an answer in pH:
    Any possibility to retain enzyme activity at PH 4.5-6, which has optimum PH of 9?

    I Am working with uricase enzyme which has optimum activity at PH 9,But i want to use this enzyme in a reaction mixture of PH 5-6 ,is it possible to retain its maximum activity or at least 70% activity at this PH ,any possibility?

  • Abid Ali added an answer in Tris Buffer:
    Why does my protein stay in the pellet of the lysate?

    Why does my protein stay in the pellet of the lysate?

    I expressed a KPC-2 Protein in NP6 cells the vector is PqE-2. After lysis (8M urea in a tris buffer pH 8), the protein is in the pellet. I have tried many different things like  different IPTG concentration 0.1Mm,0.2,0.3,0.4 and 0.5mM. sonication, microfluidizer, triton x-100, lyzozyme, and SDS. But I am unable to obtain satisfactory result. What else can I do to bring my protein into solution?

    Abid Ali · Roswell Park Cancer Institute

    First all thaks to all for given me quick and helpfull response

  • Subhash C. Kundu added an answer in Unemployment:
    Is it a fact that increase of competion has forced us to become narrow minded?

    Because of over population, unemployment etc. the competition has increased a lot, which has changed our attitude and behaviour towards our colleagues. We have become narrow minded.

    Subhash C. Kundu · Guru Jambheshwar University of Science & Technology

    Yes, along with narrow minded, --- mean minded also! This is in built in human nature.

  • Minakshi Grover added an answer in Rhizosphere:
    Any effective method for evaluation of bacterial colonization abilities on plant leaves and roots?

    I want to determine the colonization ability of some Bacillus strains on plant leaves and root (Rhizoplane, Rhizosphere and Endorhiza ) but problem is that when I isolate the bacteria the from leaves or  roots there will be many different types of bacteria and enumeration  of bacterial colonies on the basis of colony morphology is not an accurate method so I am searching for the marking method that can increase the accuracy during enumeration so please suggest some suitable marking methods. If anyone knows about any other method for evaluation of bacterial colonization abilities please guide me. Thanks  

    Minakshi Grover · Indian Council of Agricultural Research

    If molecular tools are not available, generate spontaneous rifampicin resistant mutants of your strain. Compare the desired phenotypic traits (PGP traits and growth pattern) of mutant with wild type. If unchanged, go ahead with mutant for colonization studies.

  • Tharanga Udagedara asked a question in SEM-EDS:
    Is it natural to have Sulphur in Garnet?

    I have been observing a metamorphic rock that contain Almandine garnet using SEM-EDS. The presence of garnets is confirmed by the very rock's XRD patterns (both Pyrope and Almandine are present).

    Element analysis (SEM-EDS) of various points on Almandine/pyrope shows the following general chemical composition in wt%

    Na - 0 - 1%      K - 0 - 1 %  Al - 17-19%

    Mg - 4 -7 %     Si - 25 - 30%

    Ca - 4 -1 %     (Total)Fe - 30 - 35 %

    Strangely, Sulphur is there ranging 0 to 2%

    Is it natural to have Sulphur in garnet? and are Na, K, Mg and Ca inter exchanging with each other?

    Thank you in advance

  • Anggadia Wardani added an answer in Laboratory Animals:
    How can I determine reproductive senescence in female laboratory animal with and/or without dissection?

    what characteristic we can use to determine reproductive maturity (young-adult-aged)?

    Anggadia Wardani · Gadjah Mada University

    Of course I will :D
    Thanks a lot, Maria  

  • Nita Dilawar added an answer in Graphite:
    How can I interprete the Raman spectra of carbon materials?

    The raman spectrum of a sample (biomass derived carbon material) shows only two brooad peaks at about 1353 cm-1 and 1584 cm−1, assigned to D-band and G-band, respectively. The ID/IG ratio was found to be 1.05. What does this value indicate? According to literature, While G-band is characteristic of graphite, D-band is attributed to defects, curved graphite sheets and lattice distortions in the carbon structures (Li et al. 2007). Hence, the ratio of intensity of D-band to intensity of G-band (ID/IG) is an indication of defects or graphitic order. Does it mean that there is a fixed scale of ratio by which one can ascertain the nature of material (amorphous or crystalline)? If so, can I say my material is amorphous carbon since the ID/IG ratio is more than one? I have attached the specrtum for kind perusal.

    Nita Dilawar · National Physical Laboratory - India

    The spectrum indeed indicates that the sample is amorphous in nature which can be further ascertained by XRD.

  • Joyce Chen asked a question in Staining:
    In a simultaneous double staining for IF, would I have to double my antibody concentration since mixing the two would increase the final volume?

    My primaries are from chicken and rabbit. I am staining CV-1 cells. I have previously done sequential staining and am trying to save some time.

  • Perfecto Lim added an answer in Hydrogen Sulfide:
    What is the best technique in removing H2S and CO2 from geothermal steam condensates?

    H2S - Hydrogen Sulfide gas

    CO2 - Carbon dioxide gas

    Perfecto Lim · Energy Development Corporation

    I've read somewhere that Acrolein can be used as a H2S scavenger.  Do you have any idea of its application?

  • Tobias Scheffer added an answer in Fractional Order Derivative:
    How can I use fractional order derivative in magnetoelasticity ?

    How can I use fractional order derivative in magnetoelasticity or viscoelasticity

    Tobias Scheffer · Universität des Saarlandes

    Perhaps, I have an idea about an interesting article for you:

    A. Lion, C. Kardelky: The Payne effect in finite viscoelasticity: constitutive modelling based on fractional derivatives and intrinsic time scales, International Journal of Plasticity, 2004, DOI: 10.1016/j.ijplas.2003.07.001

  • Ujval Gupta added an answer in Gaussian (Software):
    Anyone have idea which institute helps for free use of gaussian software?

    pls. send me its contact

    Ujval Gupta · Shri Mata Vaishno Devi University

    08713032019.......................and guptauji@gmail.com

  • Nithiyanantham S added an answer in Antioxidant Assays:
    Is total reducing capacity same as total antioxidant activity?

    I wish to use this total antioxidant capacity assay kit - http://www.biovision.com/total-antioxidant-capacity-tac-colorimetric-assay-kit-2834.html 

    And I wish to compare the result for total reducing capacity in http://pelagiaresearchlibrary.com/asian-journal-of-plant-science/vol4-iss2/AJPSR-2014-4-2-31-41.pdf

    So, I want to know is total reducing capacity same as total antioxidant activity? 


    Nithiyanantham S · Tierra Seed Science Pvt. Ltd.


  • Vijayendra Acharya added an answer in Historical Sociology:
    Is anybody interested to write a paper on religion and morality: is there complexities and interdependence ?

    its any invitation for writing a paper together for those who are working on religion and morality historical and sociological perspectives.

    Vijayendra Acharya · University of Mumbai

    It would be  a error to equate all the religious traditions in the world on a same level where it comes to relationship with notions of morality. While Abhrahamic religions especially Christianity and Islam are almost morality-driven religions; there is no such determinate correlation between notions about morality and religious traditions like Hinduism.  Please go through writings of Dr. Balagangadhara Rao, esp his " Heathen in His Blindnss" to better understand this line of thinking, while we can also discuss this issue here or elsewhere.  .  

  • Vishnu Priya Padmanaban added an answer in Metabolites:
    Any methods to quantify the rate of production of extracellular metabolite in bacteria?

    My bacterial culture happens to produce extracellular antimicrobial compound. I'm optimizing the conditions for production and I have to determine the rate of production with respect to incubation time. Is there any quantification methods.

    Vishnu Priya Padmanaban · Anna University/National Institute of Ocean Technology

    I have to quantify at the specific time point..the supernatant dilution against pathogens could show whether the compound is more or less but i think it does not show the exact difference in concentration (microgram/ml) with respect to incubation. 

  • Iftekhar Baloch added an answer in Bioinformatic Tools:
    Is there any tool for tissue specific classification of microRNAs?

    Please advise on tissue specific classification of miRNAs. Any bioinformatic tool available?

    Iftekhar Baloch · University of Balochistan

    @Vishnu Shukla there are many resources that enlist the genome of mitochondria and chloroplast so it would be helpful to predict miRNAs in these organelles.

  • Akshath Uchangi Satyaprasad added an answer in DMSO:
    How can I remove DMSO/DMF completely while conjugating 2, 4 DNP/Usnic acid to a peptide via the CDI method?

    I am conjugating 2, 4 DNP/Usnic acid to a peptide which is not stable in DMSO or DMF. I am using CDI (Carbonyl di-imidazole) protocol. I want to remove DMF/DMSO completely. Can anybody guide with simple method???

    Akshath Uchangi Satyaprasad · Central Food Technological Research Institute

    Dear Fernandez, Thanks for your reply.

    But, as I said I cannot use DMSO/DMF for conjugation of peptide. Not even water because CDI is extremely unstable in water. 

    Is there any way by evaporation/lyophilization or other soft process??