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.

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

Browse Topics

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • Panayot Tanchev added an answer in Bone:
    How to make a compromise between pursuing maximum coverage and optimizing the lateral inclination of the cup when having a THA for Crowe II DDH hip?

    It's also a very tricky scenario when deal with a moderate deficient acetabulum as for choosing the proper bone coverage and abduction of the cup in THA., in case of avoiding bone graf,  does anyone have a practical technique and surgic philosophy in this aspect to share with me?

    Panayot Tanchev · Medical University of Sofia

    In my opinion there are three options if yo do not want to use a bone graft after the Harris technique: 1. smaller cup and head down to 22 mm; 2. medialization of the head center, that's to say to make a deeper bed for the cup; 3. apply a special cup with enhanced and protruded upper part/arch.

  • I have a monograph coming out in April, by Routledge, on what behavioural economics might tell us about corporate governance. Any literature leads?

    I have combed the behavioural economics and corporate governance literature pretty extensively and there seems to be a gap here on the intersection between the two but I'm very interested in hearing from others on key articles, ideas etc. they think might be useful. 

  • Can anybody help me with some references in Spatial Cognition?

    I want to start to study and get some information about spatial cognition, especially focusing on Individual Differences. Can anybody help me with some references like books, chapters or available articles so that I can have and get starting info?

    Thanks in advance,

  • Shesh Kafle added an answer in Resilience:
    How can I measure ecosystem resilience?

    I am planning to conduct a research on measuring ecosystem resilience using five capitals. Grateful if you could share with me if you have developed or familiar with any other methods or approaches for measuring ecosystem resilience.

    Thank you!

    Shesh Kafle · The International Federation of Red Cross and Red Crescent Societies

    Thank you all for your very useful suggestions. I will consolidate all the suggestions, will do some more research and get back to you all if I further need your valuable suggestions.

    I have proposed a mathematical index to measure disaster resilient community based on the process and outcome indicators (http://www.ncbi.nlm.nih.gov/pubmed/22576136), which does not seem fit for measuring ecosystem resilience. I will need your insightful comments/suggestions in future too. Many thanks once again.

  • Doris Elster added an answer in Science Education:
    What are measurable effects in terms of learning outcomes (e.g. test results) of using physical acted out role-plays in science?

    There are studies evidencing students' improved attitudes and engagement from using role-plays to portray science concepts, processes and events (as analogues) and evidence of performance impact from other subjects such as History and English, but what evidence do we have in science education? Are there any studies, for example, that show effect sizes for role-play activity?

    Doris Elster · University of Bremen, Bremen, Germany

    Dear Martin,

    I use role-plays as context in my teaching and learning lab "Backstage Science". An example for this is the module "Bioinvasion of the Pacific Oyster in the Wadden Sea". The students take the role of scientists (ecologist, geologist,...) discuss the problem, conduct investigations it in the school lab (e.g. filtration rate of different mussels), discuss again the results in the role-play. Our evaluation results show that the role-play has a positive effect on students' motivation and system thinking.

    In addition we analyze the students' argumentation skills.  Our findings demonstrate that students' argumentation skills and decision making regarding socio-scientific issues is low. The role-play is a success-promising Approach to foster the necessary skills.

    Best regards, Doris

  • Margarita Stolarova added an answer in Emotion:
    What role do emotions play in social and moral norm formation and maintenance?

    So far I am familiar with the writings of Jon Elster. However, I wonder if there are other references one can point to. I'm especially interested in works providing experiments, simulations or formalizations to support their theories.

    Margarita Stolarova · Universität Konstanz

    Recently my colleagues and I looked into subjective emotional evaluations of pictures showing trivial need-of-help. Children (in our study older than 4 years of age) and young adults alike consider pictures showing everyday situations in which a child needs help to reach a trivial goal, e.g. to open a door or to reach an object on a top shelf, to be lower in valence and higher in arousal than perceptually very similar pictures with resolved need-of-help. This does not answer the larger questions you are asking, but our results suggest that subjectively uncomfortable emotions are experienced by people observing someone needing (non-dramatic, everyday) help from an early age on and that those remain almost unchanged from childhood to early adulthood. The manuscript summarizing the results with adults will be out soon, the one reporting the child-study results is under review, but if you are interested, send me a message and I will be able to mail you the manuscripts and a poster with the results I mention. Best, Margarita

  • Pouya Haghdoust added an answer in Vibration:
    Is loss Factor a property of the material ?

    Consider two cantilever beams , all the conditions equal but with different cross sections .
    Will they show the same loss factor if they start to vibrate with same condition?
    In fact I need to know if the loss factor is a property of material ?

    Pouya Haghdoust · Politecnico di Milano

    Thank you ;)

  • Hugo F Soares added an answer in Physical Therapy:
    Can the results of physical examination predict the clinical outcomes of patients with low back pain?
    Based on my literature search, it is apparent that depression and fear avoidance are the most important predictors for the development of chronic low back pain while the results of medical imaging or physical examination do not contribute much to the prediction of clinical outcomes of patients with low back pain. Have you read any articles that support the roles of physical factors (morphology or physical exam) in predicting the clinical outcomes of patients with low back pain?
    Hugo F Soares · Federal University of Minas Gerais

    All biopsychosocial aspects must be taken into consideration in the treatment of low back pain.

    The theory proposes that may be different in practice.

  • Can I have information or links on all information of (ecology, spatial distribution, and biology) of echinodermata of the Mediterranean sea?

    Can I have information or links on all information of (ecology, spatial distribution, and biology) of echinodermata of the Mediterranean sea?

    - Biodiversity of echinodermata fauna

    - All researh or articles of Paul Pallary.

    Mahadev Asaram Jadhav · Deogiri College

    the following resource becomes is good for your requirement, but it is still underconstruction, plz visit

    http://echimed.myspecies.info/

    contact with resource maintainer or administrator for taxonomic data.

  • Vuk Spasojević added an answer in CO2 Capture:
    Does anybody know what's the typical CO2 absorption capacity for Monoethanoloamine (MEA)?

    Hi All,

    I'm struggling to find a reference reporting a figure related to the CO2 capture capacity for MEA (moles of CO2/mole of MEA).

    Could you please recommend any?

    Thanks,

    Antonio

    Vuk Spasojević · Vinča Institute of Nuclear Sciences

    U can find it anywhere, just google it. Rate is 0.5 in theory, in order to remove 1mol of co2 u will need 2 moles of MEA. But in real life it is litter lower, around 0,45 - 0,48

  • How is a gradient established in CsCl gradient ultracentrifugation?

    I'm reading a protocol which to me reads that the solution in the tube is a consistent 0.3mg/ml CsCl. I've read other protocols where the gradient is established "manually" (either by layering or a gradient mixer) - as I believe you do with sucrose gradients(?) - but another source explaining the principles of the technique seemed to say that the gradient is established once you start spinning (as the Cs ions spread out differentially and this creates the gradient). Could someone explain if there are two (or more) types of CsCl gradient preparation and operation, and how these are different to sucrose gradients? This is for separation of large proteinacious species rather than DNA, and a sucrose gradient purification follows the CsCl gradient in the protocol I'm interested in. The CsCl also contains a cushion, which I believe prevents the very dense species from being pelleted out.
    Thanks in advance,

    Oliver W Bayfield · The University of York

    Yes I meant g/ml.
    I understand it is self-generating gradient now, thank you.

  • Kamaljit Chaudhry added an answer in Phage Display:
    What is the ideal percentage of glycerol to make a phage glycerol stock?

    I just amplified single clone of phage and what to make glycerol stock. Any recommended percentages of glycerol to store the phage for a longer time in -20 degree celcius?

  • Please provide me a way to reconstruct the image of the object from its digital hologram captured in In line digital holography?

    Image reconstruction from hologram

    Justice Archer · Institute of Physics of the Polish Academy of Sciences

    Hello Iftak,

    take a look at this. it be useful for your hologram reconstruction

  • B. Mallick added an answer in Phase:
    How can you find volume fraction from XRD data?

    What is the method to find volume fraction of two phases from XRD data? The two phases are  rhombohedral and cubic. What if 3 phases exist?

    Thank you.

    B. Mallick · Institute of Physics, Bhubaneswar

    I agree with both Dinesh and Tom. Simply by calculating the integrated area (or total intensity) of individual phases (2/3) you can find the volume fraction considering the density of the phases respectively.

  • Reuben N Robbins asked a question in SPSS:
    How can I combine a line graph with a scatter plot?

    I'm using SPSS, but am willing to consider other stats or graphing software. I have a data set that has patient drug levels for 2 drugs that were obtained at 5 time points (month 1, 2, 3, 4, and 5) and continuous daily data of pill taking (across 5 months which overlap/coincide with the drug level time points). Pill taking is either yes or no for any given day. I want to plot a graph that shows each individual's 2 drug levels (2 lines on one graph with 5 points) AND the daily intake activity in a scatter plot from across those same 5 months. I attached a sample of what I'm trying to achieve - it is rough and literally one graph on top of another graph. I'd like to have it all be plotted in one graph. Any ideas would be greatly appreciated.

  • Niranjan K. Naik added an answer in Yield strength:
    Is Young's modulus dependent on ultimate tensile strength and tensile strain at maximum load or yield strength and tensile strain at yield?

    The Instron tensile testing machine i used for my research findings on a fibre gave the following results, tensile stress and strain at maximum load, tensile stress and strain at yield, tensile stress and strain at break. I believe i should be able to deduce the 'Modulus using stress/strain but i don't know the particular stress and strain to pick. I am thinking since the Young's Modulus is within the limit of proportionality i should use tensile stress at yield/ tensile strain at yield to estimate the stiffness of the fibre under uniaxial tensile loading. However i don't want to be wrong which is why I am seeking the opinions of expertise in this area. Thanks

    Niranjan K. Naik · Indian Institute of Technology Bombay

    Modulus is an independent property. It does not depend on  strength and ultimate strain. 

  • Rs Khalid added an answer in Lipofectamine:
    Does anyone have any suggestions for transfecting MSCs with plasmid DNA using lipofectamine 2000 by invitrogen?

    I am using 10ug of plasmid and 10ul of lipofectamine 2000 to transfect P1 MSCs from rat. I make dilutions of both plasmid and lipofectamine separately in DMEM (without antibiotics) upto a vol of 500ul. Leave for 10 min at RT. Combine both (Now, Vol is 1 ml). Leave for 30 min at RT. Transfect my cells with it by mixing with incomplete DMEM. I keep my cells in 5% CO2 at 37C. After 24 hrs I change media to complete DMEM (10% FBS) but after RNA isolation (use 1ug for cDNA) the transfected gene expression comes out to be unchanged and sometimes a little downregulated. What can I do differently to have a succesful transfection?

    Your help is highly appreciated.

    Thank you.

    Rs Khalid · University of Karachi

    I will try these parameters as well. Thank you for your valuable suggestions.

  • Where can I get hourly weather data (specifically direct irradiance) for locations in the middle east?

    I need hourly measured weather data for different locations in the middle east, specifically in the United Arab Emirates (UAE). This includes hourly incident irradiance, ground-level temperature, relative humidity, and wind speed. In other words, the equivalent of the TMY database for North America.

    Any suggestions on how I can obtain these data?

    Chris Gueymard · Solar Consulting Services

    For TMY data: http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data2.cfm/region=2_asia_wmo_region_2

    For solar data over UAE: http://atlas.masdar.ac.ae/

    For solar data over Saudi Arabia: https://rratlas.kacare.gov.sa/RRMMPublicPortal/?q=en/Solar

    For other solar data: http://globalatlas.irena.org/

    Over UAE, the knowledgeable people to contact for other data are at Masdar: http://recrema.masdar.ac.ae/people/

  • Kamaljit Chaudhry added an answer in SDS-PAGE:
    Markers for Western Blotting?

    When performing SDS PAGE, and then western blotting, do all the brands of markers/standards/ladder perform efficiently? Do you have a non-recommended marker based on your experience? I am currently acquiring one, and would like to make sure that I don't buy an non-efficient one. Thanks!

  • Gyan Chandra Chauthwani added an answer in Zero:
    Why Lagrangian is taken as L-T and not L+T?

    We know that variation in the time integral of Lagrangian should be zero for any physical system. In this connection do we know any guess that why Lagrangian is taken as L-T and not L+T and what is the physical meaning of L-T?

    What is the physical meaning of principle of least action?

    Gyan Chandra Chauthwani · Nuclear Power Corporation of India ltd.

    @Robert J. Low 

    Thank you sir, 

    Can you please tell me the physical meaning of L-T (without being angry on me)?

  • S. Sabarathinam asked a question in Chaos:
    What is the motivation behind to prove chaos in nature?

    So far in the literature I saw so many papers to prove chaotic phenomena in  nature. I want to know about the motivation and why we study the chaotic phenomena....Actually my question is at what level we are in??..to prove or to control it.

  • Kundan Meshram added an answer in Traffic:
    How to measure lane change behaviour or lateral shifting of vehicles practically on road?

    I want to calculate the lateral shifting / lane changing behaviour of vehicle in a traffic stream. I want to know about some methods by which practically this distance can be calculated on road?

    Kundan Meshram · Maulana Azad National Institute of Technology, Bhopal

    through GPS

  • How to study sensitivity related to a commercial bank. What type of secondary data can be used for the study?

    CAMELS is a model for performance evaluation of Commercial Banks in India. C stands for Capital adequacy, A stands for Asset Quality, M stands for Management, E stands for Earning, L stands for Liquidity and S stands for sensitivity. Researcher have worked a lot on CAMEL model parameter but very few have touched the last component i.e. Sensitivity. Please guide me as to how I can approach this technical aspect for my study. My study is covering 34 Indian commercial banks over a period of 10 years.

    Onaolapo Abdrahman Adekunle · Ladoke Akintola University of Technology

    The use of sensitivity analysis for measuring changes in the values of each component of the portifolio of every bank within the

  • What happens when gibb's free energy value is positive in adsorption thermodynamic stadiues?

    I done solid liquid adsorption studies and I done thermodynamic parametric studies. When I'm doing thermodynamic calculations I got negative enthalpy and entropy values, and I got positive gibb's free energy values? As per literature's if gibb's free energy values are negative the adsorption process is spontaneous and if it is positive process is non-spontaneous. I would like to know if the process is non-spontaneous, desorption will occur or not. Anyone please help me how I can explain this study with the above mentioned values and help me to get some idea about the thermodynamic studies.
    Thank you in advance.

    Carlos Eduardo De Farias Silva · University of Padova

    In nature processes always seek the lowest energy state, then when does the adsorption, for her to be spontaneous at the end of the process energy must be less than the initial matter by contacting the adsorbent and the material to be adsorbed, the relationship spontaneity is known in thermodynamics and correlated by the Gibbs energy, the most famous, or entropy; so that its value is negative, because the end is less the initial negative.

  • Tarik Ömer Oğurtani added an answer in Cells:
    Will lattice constants be different in the case of supercell of any unit cell ?

    If somebody is working on supercell and wants to report lattice constants. Do they need to report lattice constants of supercell or unit cell. For example supercell of 3*2*1, if the lattice constants a, b, c are  divided by 3, 2, 1 respectively then it will be equivalent to lattice constants of pure unit cell. Should the lattice constants from unit cell and its supercell  be same or different?

    Tarik Ömer Oğurtani · Middle East Technical University

    Dear Gert,  I wrote above comments for those people, who are used to think in terms of concrete events and objects. ı didn't  generalized it because for me the concept supercell is fake,  but the superlattice and ordered unit cell are operationally defined entities and then they are OK.

    But you can say that ''the supercell is a simple stacking of two unit cells''. How about CuAu 11  ordered structure  that appears in temperature range of 380-410 C, which is a face centered tetragonal structure similar to  CuAu 1  that  is observed below 380 C. Where (002) planes are again alternatively gold and copper, but half-way along the a-axis of the unit cell the copper atoms switch to gold plane and vice versa. The spacing between such periodic anti-phase domain boundaries is 5 unit cells or about 20 A { one unit cell of orthorhombic superlattice  of CuAu  contains 5+5  fct  cells }, so that the domains are easily resolvable in electron microscopes. On can also observe the isolated domain boundaries in the simpler superlattice  structures such as CuAu !, although not in this case periodic. It was also observed transition from CuAu 1 to CuAu 11 in the hot stage of  TEM, as predicted,  this process is the nucleation and growth of anti-phase domains.1 Best Regards

    1. Pashley and Presşand, J. Inst. Metals, 1958-9, v.87, 419. 

    i                                       09 9

  • Amy Lu asked a question in Nuclear Membrane:
    Can flash frozen tissue be used for subcellular fractionation?

    I'm trying to get subcellular fractions (specifically, I only need the nuclear fraction) from neuronal tissue.  However, all my current samples were flash frozen and stored in -80C subsequently (for whole cell lysate, which was my original intent for the samples). 

    Does subcellular fractionation for nuclear protein require fresh tissues and cells?  Will flash freezing might cause ice crystals to form and pierce the nuclear membrane, so I wouldn't get good separation?

    Thank you in advance.

  • Afreen Haider asked a question in Buffer:
    Can anyone give a tip about dRPase assay?

    can Tris buffer interfere in any way in a NaBH4 trapping assay that is carried out to assess the dRPase activity of a protein? A 5' dRP moeity may react with amine grps in a protein to form a schiffs base. This can be reduced by NaBH4 to form a DNA-protein complex. The reaction buffer will have HEPES as the buffering agent, but the recombinant protein that I am using to assay the 5' dRPase actiivty is stored in a Tris buffer. will this interfere with my assay? 

  • Nina Giorgadze added an answer in Likert Scale:
    Which online tool is better and cheaper (free would be the best) for master thesis survey?

    I have 20 questions and Likert Scale for Rating questionnaire. Later on I would like to analyze results in SPSS. Thank you for your help!!!

    Nina Giorgadze · Vysoká škola ekonomická v Praze

    Muhammad, thank you for your answer. Though. basic account of survey monkey doesn't allow me to put there more then 10 questions and max number of responses in 100 :( About google docs I am not sure if I can extract results in SPSS for analysis. I will check out the other 2 that you mentioned. Thanks again!

  • Nathan Sweeney added an answer in Transfection:
    Does anyone know of a qPCR method which can distinguish between integrated and extrachromosomal plasmid DNA?

    I am looking to quantify plasmid integration very soon after transfection into mammalian cells. Therefore I need a qPCR method that can distinguish between integrated and extrachromosomal plasmid. Any suggestions?

    Nathan Sweeney · Imperial College London

    Hi Joe,

    I wouldn't use the mouse as a reference because these repeat sequences aren't conserved between species. In fact I've just found this publication which might be your answer?

    Otherwise, what about sucrose density gradient like the old method of purifying plasmid DNA? Get your genomic prep, sucrose gradient it, plasmid is denser than genomic. Or good old Southern blot if you can grow your suspect cells up a bit before DNA prep?

    Btw, are you testing just because you think it is interesting or it is genuinely important for you to know? I think your explanation is very reasonable, it is known that if you put enough DNA cells there will be some random low level recombination. Gene therapy with AAV or plasmid sometimes shows long-term expression in dividing populations because of this. I'm just pointing out that this isn't too unexpected so might not be worth trying to establish all these assays to prove something already known to occur. Of course I don't know your intentions and you may have a very good reason to pursue it further.

  • Why is anaerobic digestion not used for low strength wastewater?

    anaerobic treatment is usually done for high strength wastewater but not low strength wastewater. Why?

    Carlos Eduardo De Farias Silva · University of Padova

    The process of anaerobic digestion is Consisting of four phases where two are the most limiting, the material is low strength, the first, the transformation of acids is very fast, with high rates of formation which brings down the pH and hinders or eliminates the second phase, methane formation, because these bacteria are very sensitive to pH. So to have an efficient anaerobic digestion should put the amount of solids so that there is a symbiotic relationship between the acidogenic bacteria and methanogenic, ie the production rate of acids and carbonic gas must be similar to the rate of consumption and methane production.