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  • Micheál Bernard Byrne added an answer in Block Design:
    How do I go about setting up a randomized block design from scratch?

    520 pots in total. 2 plants per pot.

    13 different treatments including the control.

    4 reps per treatment and 10 pots per rep.

    Micheál Bernard Byrne

    I like your suggestions, how would you suggest that I randomize the blocks?Thanks for your input so far

  • Rocco Cavaleri added an answer in Physical Activity Assessment:
    Can anyone recommend a physical activity assessment tool for Pacific Islanders?

    I am looking for a physical activity assessment tool for Pacific Islanders. PIPAQ?Thank you in advance.

    Rocco Cavaleri

    Any time! 



  • Björn Hoffmann added an answer in Glass Substrate:
    What is the dark layer in the interface in FIB images of cross section?

    In the FIB-images sometime in the interface, e.g. thin film on glass substrate, a very thin layer (usually darker) is observed. EDX line scan showed that there are no serious changes of concentrations of elements. Also STEM also shows that in the interface there are no other layers. One can infer that this dark line is associated with optical phenomenon. Or it may be due to contamination of Ga? I would appreciate to get any references.

    Björn Hoffmann

    I also think it is a charging phenomenon. I have observed a similar thing in a thin-film silicon solar cell. See the attached image. On the left with SE detector you clearly see a darker region in the glass below the TCO. With the BSE detector is is not visible. It is also not an effect of the FIB polishing, because I also see it in cleaved samples without any FIB polishing.

  • Wajd Amly asked a question in cDNA:
    Is it really unnecessary to read cdna conc.?

    I've heard and read from different sources/ persons that after converting rna into cdna, it is unnecessary to measure its conc. Is it true?

    If I moved to rtpcr (qpcr) and take for instance 1ug cdna from each sample, how can I guarantee the accuracy of qpcr results. ( as it is possible that each sample has different cdna conc. and it was ignored by ignoring cdna conc. measurement)?

  • Kiyohiro Takahasi asked a question in Nucleic Acids:
    Is there any good 50 aa linker that is not digested in E. Coli ?

    I want to get about 50 to 100 amino acid disordered linker to add at the N or C-terminus of the target protein for some purpose. I want to express the linker added target protein in E. Coli, so linker must not be cleaved in vivo. I have HEK293T and HELA cDNA and I want to clone the linker from them because the linker is too long and it is difficult to make synthesized nucleic acid. If you have good idea please tell me. Totally another idea from me is also welcome.

  • Babar Islam asked a question in Nursing Management:
    Are there any available managerial Competence assessment Scales/Tools for first line nurse manager or Head nurses ?

    any one who have this expertise. 

  • Ombretta Colasanti asked a question in Huh7:
    Has any of you ever experienced in hepatocytes culture such a contamination?

    This is what I saw in a 25cm2 flask of Huh7 Lunet cells, today. They were not infected with HAV nor other virus, just as control. Can someone tell me what kind of contamination is that? It seems fungal to me, but still haven´t found something similar in the literature. Thank you very much for answering!

  • Gweltaz Agaesse added an answer in SYBR Green:
    What do "undetermined" CT values means in q-PCR?

    I am measuring the gene expression of my two target genes for Japanese flounder namely CDO and CSD. I used 1ug of RNA to make cDNA. I took 1ul of cDNA to be used for RT-PCR and run it on gel electrophoresis. Most of the samples shows strong bands but there are one to two samples with weak bands. After confirming the presence of bands, I used my cDNA for Q-PCR. I am using SYBR GREEN for my q-PCR. I did not do dilution and used 2ul of my cDNA samples in running q-PCR.

    The CT value for beta actin is around 22-32 and CT value for for CDO is 28-36 with some samples "undetermined". But for all my CSD genes, I got all "undetermined" CT values. 

    I would like to know if this has something to do with the concentration of my cDNA? Since I checked my primer using RT-PCR and got bands but when using the primer for q-PCR I cannot get a good result. 

    In addition, I tried diluting my cDNA samples 5x, 10x and 15x but still I get "undetermined" CT values. Can I add up to 5ul of my samples in running q-PCR?

    + 1 more attachment

    Gweltaz Agaesse

    Hi !

    Depending on your machine it can display undetermined CT or NO CT.

    It means that the cDNA concentration is either very weak or there is no cDNA (concentration=0).

    I think your concentration is quite weak as you normally have a much lower CT with housekeeping genes cDNA...

    Do you quantify your RNA concentration before doing the Reverse transcription ?

  • Israel Nelken added an answer in Binomial Distribution:
    How to compute transient probability in excitatory and inhibitory input integration based on Perfect integrate model?

    In perfect integrate model of single neuron, there is no leaky channel. When we set a threshold for spike generation as 'theta', excitatory input rate is 'r_e', each step of excitatory input would increase the membrane potential for on uniform amplitude 'A'. To simplify the question, we set A = 1.

    In this case: input rate = r_e, output rate = r_e*A/theta = r_e/theta

    so the generation of output is a gamma process.

    BUT, in real neuron, there should be both excitatory input and inhibitory input to keep the network balance.

    So, each inhibitory input would cancel a excitatory input. And excitatory input and inhibitory input are both from Poisson distribution. Based on perfect model, excitatory and inhibitory input cause exactly same amplitude A effect but in reversed direction.

    In this case, let's assume k inputs would generate a spike, so the inputs between two spikes are 2k+m, excitatory input: k+m, inhibitory input is k, and net input is m, which cause the membrane potential rise to threshold.

    When we are computing the transient probability of the new neuron model, we set probability of increase as r_e/(r_e+r_i) and probability of decrease as r_i/(r_i+r_e). Then this is a binomial distribution.

    Resulted Transient Probability is the product of a probability of Poisson Process (to generate 2k+m inputs in total) and probability of binomial distribution (to have k+m excitatory inputs and k inhibitory inputs)

    I was wondering to simplify the process by making a net input (m spikes) from Poisson Process

    Or I would say, the new net_rate = r_e-r_i

    so we don't need transient probability (Markov process) to understand the transient process from one spike to another, this make the problem again a pseudo-excitatoryinput-only perfect model.

    Does this applicable? My supervisor said I should not cancel a excitatory input with a inhibitory input, because Poisson process subtract a Poisson process doesn't make sense. But if I cancel randomly (with the right number), this is again a Poisson Process.

    Israel Nelken

    The process you describe is called a birth-and-death process, and has been extensively studied in the context e.g. of queuing theory. Most recently, I think this has been used by e.g. Mike Shadlen to account for his neurons that integrate to threshold in order to do decision making.

    You can't make the reduction to a Poisson process with a rate that is the difference. While the averages fit, the distribution would be substantially narrower, and so the firing probabilities would be much less. As an example, think about a process with r_e=r_i. Your equivalent Poisson process would have a rate of 0, so be identically equal to 0, but the model with two separate processes of excitation and inhibition would still have probability to fire.

  • Paul F Luckham added an answer in Rheology:
    While testing the rheology of fluids, can the results of rotational tests be compared with those of the oscillatory tests?

    The fluid is a polymer nano composite.

    Paul F Luckham

    Alan is quite right and you may find this video from Malvern instruments helpful


    Note that the rule is generally good for polymer systems but not for particle dispersions


  • Alexander Komashie added an answer in Arena (Simulation Software):
    With ARENA Simulation software, how can you create an entity which will assume a value of 0 and 1 in 45 seconds time interval?

    The entity will only assume a value of 0 and 1, with 45 seconds time interval, the entities will not come in batch value but only one arrival at a time

    Alexander Komashie

    I am not sure about current version of Arena but older versions did not have any clever way of doing these things. You can however, do this by creating a separate control loop to alternate the values of a variable you assign to the entity. See example in Arena 9 attached.

  • Christian Müller asked a question in IRB:
    Has there any non-interventional primary data collection with digital sensors/devices has been done without any health care professional?

    But only with Patient reported/measured data?

    I am interested in the prospectively defined analysis of such dataworkflows of wearables, scales, smartwatches. Is there any experience with IRB/EC requests regarding informed consent, when the recruitment of the patients is done via an app?

  • Muhammad Khattab added an answer in Solvents:
    What does it mean when blank (solvent) has intense peak in excitation spectrum, but weak one in emission (<10%) of sample intensity?

    Also, sometimes I notice the reverse where weak excitation peak and strong emission peak. For the best of my knowledge, the solvent peak should be (<10%) of sample peak in both excitation and emission measurements.

    Muhammad Khattab

    I mean when i use very diluted solution of studied compound (1uM) the solvent background becomes 100% not (<10%) of sample peak. this may happen in excitation measurement and not in emission measurement and vice versa

  • Nikos Pnevmatikos added an answer in Earthquake:
    How can I determine the predominant frequency of an earthquake ?

    Dear researchers
    How can I determine the predominante frequency of an earthquake from it ground acceleration record using MATLAB.

    Best regards.  

    Nikos Pnevmatikos

    and some for FFT

    + 2 more attachments

  • Hazim Hashim Tahir added an answer in Universe:
    Why is there something instead of nothing ?

     LET US START BY WHAT  Robert Adler  WROTE   ON 6 NOVEMBER 2014--:
    People have wrestled with the mystery of why the universe exists for thousands of years. Pretty much every ancient culture came up with its own creation story - most of them leaving the matter in the hands of the gods - and philosophers have written reams on the subject. But science has had little to say about this ultimate question.

    Hazim Hashim Tahir

    Dear Colleagues,

    Good Day,

    “Nothing is true, everything is permitted.”

                                                                      ~HASSAN-I SABBAH

  • Lukas Alberts added an answer in Physical Vapor Deposition (PVD):
    When can we say that the color of plasma is a sign of self-sputtering?
    I can observe an intense green color for a copper cathode, a clear nice blue for stainless steel. But is that enough to argue there is self-sputtering ? Working pressure above 50 Pa, more than 15 W/cm2 DC power. Do I need a special window to make VUV OES? Thanks.
    Lukas Alberts

    I wrote some more into the abstract of the video available in my contributions. (breathing-plasma)

    No post-doc position in Limoges?

  • Toni slotnes-obrien added an answer in Diabetes:
    Diabetic's nurse and patient's self-care?

    Does anyone know good, relevant studies about diabetic nurse giving self-care education for patients with diabetes ?

    Toni slotnes-obrien

    There is a good diabetes education program in the UK called Xpert. The link to the benefits found from a study is attached  

  • Dulce Rodrigues added an answer in Friction-Stir Welding:
    What are ductility criteria for friction-stir welded AA 6061 plates?

    Normally in optimization perspective for FSW of higher grade Aluminum, the harness decreases and it is considered as higher the better. Obviously a decrease in hardness leads to increase in ductility. So what should be the optimization criteria in this case if bend test is considered as one of the output?

    Dulce Rodrigues

    Please see the reference.

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: In current work, linear stress-hardness relationships are established, relating the hardness in different AA 6082-T6 weld zones with local tensile properties. The welds were performed by friction stir welding (FSW), using varying welding parameters, in order to obtain a diversified range of weld mismatch conditions. Local tensile properties for the thermo-mechanical-affected zone (TMAZ) and heat-affected zone (HAZ) were assessed from tensile testing of transverse samples using digital image correlation (DIC). The proposed stress-hardness relationships, which relate hardness with yield strength and flow stress, at different plastic deformation values, are suitable to be used for assessing plastic properties, from hardness data, for AA 6082 alloys, in the naturally aged and overaged conditions, characteristic of different weld zones of any type of welds in this aluminium alloy. The evolution of friction stir welds’ local and global tensile properties, with varying welding parameters, is also analysed. It is shown that in spite of the large scatter in local mechanical properties, the global strength of the welds does not vary significantly. This behaviour is explained based on local plastic strain distribution analysis.
      International Journal of Advanced Manufacturing Technology 07/2015; DOI:10.1007/s00170-015-6866-z
  • Leidy Elvira Bejarano Urrego added an answer in Masonry:
    How can I calculate normal and shear stiffness of an interface element for mortar interface and internal brick interface?

    To define mortar interface and brick crack interface during modeling of masonry, i need normal and shear stiffness (Kn and Kt). I found relationship to calculate these values attached here for mortar interface. But in my case Eu < Ej. So how can i calculate? And how can we estimate clay brick normal and shear stiffness to define brick crack at middle of the brick?  I am using DIANA for it. Please suggest me.

    Leidy Elvira Bejarano Urrego

    In my case, young modulus for unit and mortar are very close each other, which causes extremely high values of Kn if I use the equation presented by Lorenco.

    Do you know if there is any way to calculate Kn for the interface as a function of Kunit and Kmortar? Is Kn somewhere in between Kunit and Kmortar??? thanks

  • Gaur MOHAN Mathur asked a question in Soil Organic Carbon:
    How to convert Organic carbon (%) of soil for value & interpretation in to available nitrogen (Kg/Ha) & rating ?

    Say in my area soil organic carbon measured is 0.28, 0.30, 0.18 %

    as per soil fertility rating it is low in organic carbon or low in nitrogen (Kg/Ha)

    now for all my data like above I want to convert into available nitrogen (Kg/Ha)

    so what will be any formulae ?

  • Balaji S N asked a question in Sucrose Gradient:
    How to extract(isolate) the RBC cytosol protein for phosphorylation pattern analysis from RBC lysate?

    Currently, I'm using the TritonX100 for lysis and sucrose gradient to separate the cytoskeleton method. But I'm not getting good bands. If anyone knows a good protocol, please share with me.

  • Mayavati Mhaske added an answer in Quality of Health Care:
    How do I measure the quality of health care in hospitals?

    Many of the avialble studies on patients satisfaction with health care in hospitals do not reflect the correct picture! mostly overestimate the quality. 

    When we study the health care quality in hospitlas, what dimension should we include? whom to ask {Which sample, what characteristics}? to study QoC in qualitative or Quantitative approach?

    Mayavati Mhaske

    Quality of health services can be assessed through patient feedback and scales are available for that on the net for evaluation of services provided by public or private hospitals .

  • Daniela Iamartino added an answer in RNA-Seq:
    Can I use DNase 1 treatment (invitrogen) for RNA extraction, which I will send to RNA-seq?

    Can I use DNase 1 treatment (invitrogen) for RNA extraction which will send to RNA-seq?

    Daniela Iamartino

    Of course, you have to, highly recommended if you don't want to seq the DNA.

  • Yuri Yegorov added an answer in Internal migration:
    Can anyone please share questionnaire related to climate induce INTERNAL migration? Looking into economic opportunities and resilience?


    Yuri Yegorov

    Why do you think that such a questionnaire already exists? Maybe you are the first to figure it out. There should be empirical studies about the reasons for internal migration, and you might use some basic questions from them. Besides standard questions about age, sex, education, income, you may ask what was the pushing factor leading to internal migration for you. You may offer a set of reasons (multiple-choice question) and apart from standard answers (relocation to join family, to study, to find job) you may ask about climate change reasons (like: where do you like the weather better, at old or new destination? do you have water scarcity? etc). It is a piece of art. Before making research just test it on your friends, and then find what formulations should be changed.

  • Jainesh Jhaveri asked a question in Beds:
    Can anybody in the group/forum send us the supplier details of oxygen probe for tubular packed bed reactor?

    Is there anyone in the group/forum who can help me to select oxygen sensor for tubular packed bed reactor? Our reactor operates at 1500C and 15 bar under extreme pH conditions. We are in need of oxygen probe for the detecting its consumption in oxidation reaction, and hence to find the conversion of the reaction. I need the information of suppliers of such instruments to measure online during continuous operation.

  • Alberto Muñoz added an answer in High-Dimensional Data Analysis:
    In SVM with R, how do I get the points that were projected in the higher dimension?

    I will use the points in the higher dimension for clustering.

    Alberto Muñoz

    If you want to obtain particular coordinates, do the following. First, transform the kernel matrix ( k(x_i,x_j) ) to a distance matrix, by applying   d(x_i,x_j) = k(x_i,x_i) + k(x_j,x_j)+2 k(x_i,x_j).  Once you have the distance matrix, apply MDS (Multidimensional Scaling) to obtain Euclidean coordinates and choose as many dimensions as you need.

  • Germán Gémar asked a question in Hospitality Industry:
    Do you know any database that report the length of stay for the hospitality industry?

    I would find a database of hotels that report the length of stay of customers.

    Do you know any database for the hospitality industry?

    Thanks a lot

  • Guillaume ten Dam added an answer in GC-MS Analysis:
    What is the basic principle for choosing solvents for GC-MS analysis?

    Do the samples used for GC-MS analysis vary according to the compounds to be analysed? What if one is not sure of the compounds formed?

    Guillaume ten Dam

    Dear Sarbani,

    The solvent used in GCMS are mostly a-polar solvents since polar solvents can cause disturb the chromatography, like fronting, tailing and peak splitting. Generally, a solvent is chosen with a much lower boiling than the compounds. If the boiling points are to close distortion of the chromatography will happen. Typical solvents are hexane and iso-octane. More polar solvents like acetonitril and toluene can be used, but you probably need to invest more time in the development of the injection method with these solvents. Another influence is also the sample pre-treatment, e.g. in what solvent will your extract end up after the last step of the preparation procedure.

  • M. Antonia Álvarez-Fernández added an answer in Plant Extracts:
    Does anyone have another method for antioxidant activity for plant extracts other than DPPH, FRAP and ABTS?

    I want literature on antioxidant assays for plant extracts in detail along with mechanism.

    M. Antonia Álvarez-Fernández

    ORAC is a good option, I work with that method using TROLOX .

    Effects of the strawberry (fragaria ananassa) purée elaboration process on non-anthocyanin phenolic composition and antioxidant activity.

  • Jeroen Speybroeck added an answer in Mark-Recapture:
    What are some Capture Mark Recapture techniques possible for Palmate Newts (Lissotriton helveticus) ?

    Dear colleagues, for a study (spring 2016) I am designing on Amphibiocystidium infections in Palmate newts (Lissotriton helveticus) in the Netherlands I am wondering if there are some capture - (mark)- recapture techniques available for this species. I am familiair with these techniques in other Amphibian species but I am wondering if these are applicable to Palmate newts (f.e. are belly patterns useable)? Thank you very much in advance!

    Jeroen Speybroeck

    I have stopped using that particular piece of software at some point in the past. It might work fine if your pictures are properly standardised in their outlook, similarly cropped etc, though, but personally I switched to a formalisation of the spot pattern into a code, which does not pose (such) stringent demands on the images and as such probably takes a similar amount of time to process. But that's all thanks to the spot pattern, so Germán's suggestion is definitely worth a try.