Q&A

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

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  • Kindly Suggest some useful papers on electoral behaviour, indicating determinants and methodology?

    One of my students is working on Electoral behaviour in Lahore. She wants to compare general and bye elections in Lahore (she can change the focus of the study at the moment). Kindly suggest some useful readings in this regard, outlining determinants of the electoral behaviour and methodology to be used. 
    Furthermore, Kindly suggest some scale that has already been developed to study electoral behaviour. 

    R. Morris Coats · Nicholls State University

    You might have her read my paper on special vs general elections in Louisiana. Special versus  general elections and composition of the voters: Evidence from Louisiana school tax elections.  Then she can look at Google scholar for papers that cited it and at my references in the past.  While not as directly related, my paper in Kyklos in 2009 might also be of interest.

  • Robin Raju added an answer in HFSS:
    Is it possible to plot refractive index vs frequency graph in HFSS?

    I want to know about zero refractive index materials. How can we draw a zero refractive index surface above microstrip patch antenna with CLR and SRR structures.

    Robin Raju · University of Manitoba

    Numan, A.B.; Sharawi, M.S., "Extraction of Material Parameters for Metamaterials Using a Full-Wave Simulator [Education Column]," Antennas and Propagation Magazine, IEEE , vol.55, no.5, pp.202,211, Oct. 2013

  • Karl Popp asked a question in Medical Devices:
    Failure of medical devices? i need studies regarding failures in medial devices that leads to injuries or deaths of patients ?

    failure of medical devices can be dangerous. i am investigating the failure and malfunction of such devices that can be avoided by introducing additional securing algorithms to avoid such failures. Who can help? Examples are infusion pumps, breathing devices etc.

  • Guillermo Antonio Reyes asked a question in Cocoa:
    Someone could helpme with somework cell counting in a Neubauer chamber and determination of the feasibility FDA embryogenic cell suspension of banana?

    embryogenic cell suspensions cocoa coffee and bananas
    I need it for an essay

    appreciate your help

  • What are the research directions in quantum biology?

    Quantum biology refers to applications of quantum mechanics to biological objects and problems (Wikipedia). Erwin Schrödinger, one of the founders of quantum theory in physics, was also one of the first scientists to suggest a study of quantum biology in his 1944 book What Is Life? (see link). Many biological processes involve the conversion of energy into forms that are usable for chemical transformations and are quantum mechanical in nature (Wikipedia). A recent book Life on the Edge: The Coming of Age of Quantum Biology by Jim Al-Khalili and Johnjoe McFadden is a good reference on Quantum Biology. As this is a deep theory, the space here is not enough to write all in detail about quantum biology. I welcome views on quantum biology and especially the research directions in this area. Thanks!

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

    Do you think that the social consequences of the findings in Quantum Physics belong to the research field of Quantum Biology (e.g. the invention of the .... used during daily life), or not?

  • How to map Affymetrix probe IDS to HGNC gene symbol?

    I have around 54K probe IDs from the platform HGU95AV2 of affymetrix. I tried bioMart package in R but got less 1% of the probe IDs mapped. Is there any alternate to specifically map to HGNC symbols?

  • Islam Saadeldin added an answer in Tissue Culture:
    I am looking for transwell inserts for tissue culture purposes with pore size 0.22 µm. Could you please let me know where I can buy them from?

    These transwells are using in order to get well polarized mono or bilayers cell line

     Best regards

    Islam Saadeldin · Zagazig University

    I worked on "Corning" 0.4 µm, 24-well dish.

    Please refer to a similar Q&A in RG:

    https://www.researchgate.net/post/Does_anyone_have_a_vendor_source_for_transwell_cell_culture_inserts_with_a_pore_size_of_022_m_or_smaller

    Good Luck!

  • Arun Nadaradjane asked a question in Rhodamine 123:
    What is the role of rhodamine 123 in detecting Apoptosis?

    In cancer research

  • What would you do if you received a report from the reviewer of your paper asking for a major revision, with which you completely disagree?
    What would be your response? Would you appeal to the editor by asking him/her to make the final decision, would you be weak and amend what you believe is right, would you argue back with facts, would you re-submit the paper to another journal?
    Hanno Krieger · retired from Justus-Liebig-Universität Gießen

    Dear Mahfuz,

    I agree, I know these situations. They are not bad for the authors, because the cause and provoke thinking of the editor.

  • Dudley J Benton added an answer in FLUENT:
    Is there any proper way to run fluent in parallel with the best efficiency?

    Unfortunately, software's codes are not written in their best way(or I think so). When you try to change from serial to 2-core parallel processor, efficiency is more enhanced than changing from 2-core to 4-core. I mean the computation capacity-core slope is getting lower while the number of cores increased. In my point of view, it shows that the relation of variables may have a better possible arrangement.

    Dudley J Benton · McHale Performance

    If you have at least 4 or 8 processors and all of them aren't running at more than 25% utilization, that's a problem with the coding that you probably can't fix. It could be a domain discretization issue, but not likely. You'll never get them to all be running at anywhere near 100% utilization.

  • Can anyone list out good journals for biodiversity research in the field of ecosystem service?

    I wish to know the journals in the field of ecosystem service which publishes  original research article very rapidly.

    Katja Neves · Concordia University Montreal

    Conservation Letters has had some interesting articles on this topic; the 4 Environment and Planning journals as well; I would also check Environmental Science & Policy

  • Sanjeet Limbu added an answer in Diesel Fuels:
    Can anyone suggest good materials for a diesel fuel sampling machine?

    There is need for fuel sampling for heavy duty vehicles for industry use

    Sanjeet Limbu · Michigan Technological University

    I am interested in analysis of  fuel contamination used in heavy vehicles. So designing system for checking the particle contamination and other parameter- additives bio-fuels, free water, sulfur content, lubricity , liquid dilution, viscosity and microbial contamination of Diesel Fuel are central point of interest.

    While doing the test sampling the measurement must maintain homogeneity of the sample so to reflect real mixture composition. Particles as small as 4 -6 microns must be detected by the sampling test, for ensuring better engine relibility

  • Cristina Maracci added an answer in Enzymes:
    Does Km (Michaelis constant) vary with enzyme concentration?

    Does Km (Michaelis constant) vary with enzyme concentration

    Vmax depends on enzyme concentration since Vmax = 2Km

    why Km does not depend on enzyme concentration if Km is the substrate concentration where V = 1/2 Vmax.

    If you increase Vmax, shouldn't Km increase as well since it is dependent on it?

    Cristina Maracci · Max Planck Institute for Biophysical Chemistry

    The KM does not vary with enzyme concentration (tit's a "constant", right?). What can vary is the Vmax, therefore efficiency of an enzyme is usually expressed as the ratio Vmax/E. 

  • Can the Quadrupole Plasmon Resonances generate birefringence?

     I synthesized metal nanoparticles. In ripening stage, Uv-vis spectrum suffers a red-shift and broadening of peak by quadrupole plasmon resonance. when I observe the nanoparticles with light that cross the sample, a blue color is produced. meanwhile, if I observe with light reflect the sample a different color is produced. This can be interpreted as birefringence? From UV-vis spetrum I could think that my NPS are anisotropic. The anisotropic nanoparticles (plates, spheroids, rods, triangles, etc.) can have birefringence? How is the relationship between quadupole plasmon resonance and birefringence in anisotropic nanoparticles?.

  • Danijela Markovic added an answer in Cancer Cells:
    Anyone else have issues with varying or no activity of recombinant IL4 (or other cytokines) between batches even when lot number doesn't change?

    I have been using recombinant IL4 to stimulate proliferation and survival directly in epithelial cancer cells that have IL4 receptors.  I have tried 4 or more companies at this point, and BD seems to elicit the largest responses in cancer cells, but I often get what appears to be dead IL4 from them even when the new batch has the same lot number of a previous batch that was "working" with the same cells.  I've sent numerous tubes back and it keeps happening randomly.  They may be at their whit's end with sending us any more, but I don't get great responses with Tonbo or Peprotech IL4 (which have the same amino acid sequence).  I'm hoping other people have had the same issue?

    Danijela Markovic · California Institute of Technology

    try R&D, they are more expensive but very reliable. Although there are many companies that sell peptides for lower prices, the purification of the peptide can be a problem.

  • Bagher Zahabiyoun added an answer in P Value:
    In interpreting the p-value
    In interpreting significance of constant value (b) in linear equation (y=ax+b) from p-value when it is more that 0.05, can we conclude that the value of b is insignificant? (the same conclusion as for the value of a?)
    Bagher Zahabiyoun · Iran University of Science and Technology

    Dear Netra, If this is so, why the p-value for the intercept is calculated by all statistical packages? thanks

  • Suad Gaco added an answer in Abdominal Abscess:
    Do you think that re-laparoscopy is the best way to manage laparoscopic complications?

    Abdominal abscesses, free abdominal fluid, bile leakage or hemorrhagic collections could be some laparoscopic complications: what's the best way to manage these problems,"'re-laparoscopy" or open surgery?

    Suad Gaco · Cantonal Hospital of Bihac

    Najvaznije je iskustvo kirurga, prepoznati komplikaciju i sto prije intervenirati.Manje je bitno da li je to laparaskopija ili laparatomija.

  • Dudley J Benton added an answer in Density:
    How can I calculate the power density and the energy density from CV obtained capacity?

    I would like to know how to calculate the energy density and the power density for a capacitor using these 2 equations: E (Wh/Kg) = 1/8 C (F/g) / V²(volt) P (W/Kg) = E (Wh/Kg) x scan rate (Volt/sec) / V (volt).

    I tried to calculate it, but I don't know how to convert these different units.

    My problem is units conversion, if any body could help me.

    for example c = 400 farad/g  Volt V = 2.5 Volt  Scan rate 1 mV/sec

    What would be the power and energy density in that case?

    Dudley J Benton · McHale Performance

    As far as the energy storage goes, farad is a coulomb per volt, an ampere is a coulomb per second, and a Joule is an amp volt second. You can divide it by mass or area to get an energy "density." See for instance the link below for various units and formula. The power is another matter. Capacitors can charge and discharge quite rapidly, but not instantaneously. Besides the capacitance and area, it depends on the load.

  • Can anyone suggest why I don't see a positive stain when immunostaining cultured cells?

    I have been doing immunostaining of cultured cells. The current issue is that I don't see any positive stain. One thing that worries me is the fixation and permeabilization step. Is it possible that the protein (both in cytoplasm and nucleus) got lost or washed away during the steps? I used ice cold acetone for 10 min RT. I have been searching the fixation and permeabilization steps online. The are pretty similar. Has anybody ever had this experience before? The same procedure works fine in tissue sample. It's tricky for cultured cells on slide. 

    Steingrimur Stefansson · HeMemics Biotechnologies Inc

    Hi Zhenning, it could be that you are not using the best primary antibody for your studies.

    Dako has great products for labeled secondary's, lectins, etc, but they are not well known for their primary antibodies.

    I suggest that you look for another  primary antibody that  recognizes your protein when fixed and what fixation procedure works. Here are some antibody search engines:

    http://www.linscottsdirectory.com/

    http://www.antibodydirectory.com/

    http://www.antibodyresource.com/findantibody.html

  • Masoud Vatani added an answer in Fibroblast:
    Do human fibroblasts get transformed on S.C injection into mice?

    I have injected human fibroblasts into mice. On harvesting the tumors, will I have a combination of mouse and human fibroblasts or human fibroblasts transformed into mouse like. How can they be differentiated?

    Masoud Vatani · Islamic Azad University Khorasgan (Isfahan) Branch

    This action is rare ,because they arent adaptation from HLA antigen but this practice is intrest about experimental study 

  • Zainab Jaafar added an answer in Teacher Education:
    What's your opinion of cameras in classrooms at all levels of education, elementary through university?

    Cameras in classrooms are becoming more common.  Often two cameras are used, one in the back to show the teacher and one in the front to show the students.  One of the primary rationales behind this use is safety concerns due to numerous school shootings.  Monitoring student behavior is another reason for their use.

    There are other potential uses.  For teacher evaluation, rather than disrupting a class with a personal visit an evaluator could observe the camera feed.  Students of teacher education could observe a number of teachers more conveniently with the camera feeds. 

    What are other positive uses?  What are the negatives?

    Zainab Jaafar · University of Basrah

    Raising anxiety among students (and perhaps among teachers) may be the most negative point. 

  • What percentage of HNO3 and HCl is sufficient to digest a soil sample to determine Cd concentration?

    Please mention the related and valid international guideline.

    Johnson Rotimi Oluremi · Ladoke Akintola University of Technology

    Also 3:1:1 of HNO3:HCl:H2O2 can also be used.

  • Fulvio M. Rivano added an answer in Bulk Density:
    How can I test soil water-filled pore space?

    Hi, I am doing soil  water-filled pore space (WFPS). I don't know why researchers tend to make soil bulk density at 1.1 g/cm3 during the test? Besides, what factors will affect the results of WFPS? Is WFPS the constant for a specific soil?

    Thank you very much.

  • Carlo Drago added an answer in ARIMA:
    How can I make a time-series stationary?

    Since I am implementing the ARIMA model, I need a stationary time series.
    My problem is that for a bunch of my series it seems that neither the differentiation nor the Box-Cox can help (i.e. the data remain non-stationary).
    Is there any other method that could be useful in reaching stationarity?
    I also tried to differentiate the LN of the time series itself, but I didn't achieve the expected result.
    Thank you

    Carlo Drago · Università degli studi Niccolò Cusano

    Hello Debora, you can use various methodologies in order to obtain stationarity on your data: 

    1. transforming your data using square roots. You have already tried the LN transformation maybe (it depends on your series) you can obtain a stationary time series by considering the square roots transformation.

    2. detrending or de-seasonalizing your data. If you can eliminate the trend or the seasonality hopefully you can obtain a stationary time series.

    3. differencing two times your series or more..

    4. considering eventual other problems like outliers (I assume you have already considered the problem but maybe they can be a possibility to take in to account).

    In general you have to consider at the same time points in your model construction like structural changes. I think for an ARIMA model it is necessary to take in to account not too many observation (parameter drift could be frequent) and surely eventual breaks.

    In general differencing a time series could be not enough in order to obtain a stationary time series.

    I hope these considerations are useful for you.

    Kind Regards,

    Carlo

  • Safa Ezzine asked a question in SEM Analysis:
    Why SEM analysis can't detect lithium?

    why SEM detect only elements for Z>5

  • Amy L Shelton added an answer in Volition:
    What exactly are the signal processing mechanisms performed by the parietal cortex during navigation?

    The parietal cortex has long been associated with navigation, but the specific function has been somewhat difficult to pin down. One theory is more sensory and holds that parietal neurons encode path or distance relative to various reference frames in the environment (landmarks, local vs global space, personal distance or path integration). Another theory is more movement oriented, and holds that the parietal cortex encodes the procedural parts of navigation - the volitional ability to move along the given path in a particular context, linking to the behavior and not the environment. It is possible the parietal cortex aligns both - ideothetic and allothetic spatial information? Is it put in register? However, I have yet to see strong evidence for this combination in navigation tasks. 

    Does anyone have an idea about what exactly are the signal processing mechanisms performed by the parietal cortex during navigation? 

    Amy L Shelton · Johns Hopkins University

    We have spent some time thinking about this very question in human navigation.  First, we find that the answer will depend heavily on which part of the parietal cortex.  If human parietal cortex is analogous to other primates in function, then the different regions within the parietal cortex will have different roles.  We consistently find that the superior parietal cortex (which is still broad) is associated with a pretty broad range of behavioral manipulations--sensitive to having to process information over turns.  The inferior parietal cortex has been more elusive in understanding its role in navigation, but it has clear involvement in object-based transformations.  In short, I don't think we have answered your question with the current data available, but it is an area ripe for work.  I suspect that some of the high resolution imaging techniques might help us way in on some of the functional mapping, and then we can start to develop more testable models.

  • Cecilia Santrich added an answer in QIAGEN:
    Does anyone have any advice about baffling low concentrations of DNA on Qubit ?

    I extracted whole blood samples using the Qiagen DNeasy blood and tissue kit. When quantifying the DNA on the Qubit, I get baffling low DNA concentrations. Is there something that I might be doing wrong? Is there a way to increase my DNA yield after extractions?

    Thank you!

    Cecilia Santrich · Indiana University-Purdue University Indianapolis

    Hello  Sonja,

    I have extracted a lot of fresh human blood samples using the QIAMP DNA blood mini kit from QIAGEN (cat 51106 250 samples). I use 200 -300 uL  of blood and elute in 40 uL of  buffer. The DNA concentration with Qubit   dsDNA broad range assay kit (cat Q3850 Life Techn) ranges from 40 - 400 ng/uL. When I use buffy coat also I get from 40 - 800 ng/uL depending of each sample. You need to consider a couple of things: 1. The extraction kit you use is for certain species (you do not mention blood of what species you are extracting), the genomic DNA size depend of the species and also the type of column every kit is intended for. 2. The DNA yield depends of what is the starting volume of blood you are using, you cannot overload the column.3. When you said you get a low concentration is based on your assumption or your are comparing with another DNA reading method as Nanodrop, remember the readings with QUBIT are much less that with Nanodrop (for blood is probably 3 fold less than with Nanodrop) this is because the Qubit is reading intact DNA  and it is very specific just to read good quality of DNA. I hope this help.

    Cecilia Santrich

  • Salim Heddam added an answer in ANFIS:
    Genfis2 waring message?

    Hi every one, I'm writing an ANFIS model using genfis2, six inputs , one output, I receive a warning message "warning: Rank deficient, rank=0, tol=Na", what does it mean, and how can I solve this problem?

    Salim Heddam · University 20 Août 1955 SKIKDA 21000

    Dear Khaled

    Please find attached two files regarding the use of GENFIS2

    sincerely  your

    salim HEDDAM

  • Eliab Z. Opiyo added an answer in Tensile Test:
    Is it possible to do tensile testing on pipes?

    I would like to know whether tensile testing can be applied for pipes or not. Because pipes are circular in shape, which seems impossible for tensile machines to hold/grip. Any suggestions?

    Eliab Z. Opiyo · Delft University Of Technology

     Yes .. you only need a proper mechanism for gripping/securing the specimen, which in this case happened to be a pipe with circular cross-section.

  • Lauric Henneton added an answer in Fear:
    How would you suggest quantifying fear and its evolution in history?

    I'm interested in the early modern period (1500-1800)

    Emotions in general and fear in particular can hardly be quantified, measured and visualized but I'm looking for symptoms of fear that could be quantified and tracked over time. One idea is religious processions.

    Lauric Henneton · Université de Versailles Saint-Quentin

    Glenn:

    Thanks for this. Actually, you can collect evidence in colonial records (the Massachusetts Bay Colony records for instance) that state the reasons why proclaiming a day of fast and humiliation, and they clearly mark communal fear (objects are varied, from the weather compromising the harvest to the diplomatic situation in Europe). But that's something I did in my dissertation years ago. And you can actually modelize that year after year. There have been similar studies about processions in 17th century Britanny, that's why I'm mentioning them.

    Defense expenditure and military preparation is indeed a point that would work. In the American colonial archives, though, sums are now always mentioned, and a methodological problem would be the shifting value of money. I know there's a tool out there enabling currency conversion, but I'm not sure how reliable it is...

    On a related matter, in some of the New England cases I've studied, relatively low degrees of fear call for defensive preparations (fixing fortifications, more nightly watches...) while very acute fear spurs preemptive attacks (also the case in Bacon's Rebellion in late 17C Virginia). But clearly a theme to investigate.

    Thanks!