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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  • Sonia Monken added an answer in Disability Policy:
    Is anyone done or is doing research on Permanent Supportive Housing?

    We are in the process of opening a PSH community targeting intellectually disabled people wish to live independently. If anyone with experience with this population would like to share we would love to hear from you.

    Sonia Monken · Universidade Nove de Julho

    Nadine,  We`re  attending intelectual disable. Adults  by APOIE ( www.apoie.org.br). 

    We `ve prepering for they living in a PHS . One of experience and best practices that we found is in Cheevrestown , Dublin.  Contact Mrs goconnor@cheeverstown.ie  .

    Best Regards.

  • Dissolving tetracycline in water?

    Hello,

    I want to prepare a 5mg/mL tetracycline solution to be administered to ant colonies. I cannot use methanol or ethanol for solubilisation. My attempts with dissolving directly in MQwater resulted in precipitation. Anyone would have tips on how to better dissolve tetracycline hydrochloride?

    Thanks

    Eduardo Goncalves Paterson Fox · University of Lausanne

    Thanks Jean, I saw about heating online but was unsure how much heating. Have you tried it this way? Cheers!

  • JC Spender added an answer in Research Topics:
    What are the steps to be considered in framing a conceptual framework?

    what things to be considered while writing a conceptual framework and how to link the concepts and theories to our research topic and how to make a conceptual framework??

    JC Spender · Kozminski University

    @Nicole,

    You are providing a framework - borrowed, I guess, from an uncited methodology professor somewhere.

    Providing a framework, whether interesting or pedestrian, is not answering Syamala's question - to wit, how do you create a framework.

  • How can I calculate the gradient of initial state equations?

    If you have linear dynamical systems with infinite dimensional distributed systems. How can determine the initial gradient state if we have state equation with initial state and augmented by output function?

    Raheam A Mansor Al-Saphory · University of Tikrit

    Hernando Castaneda Marin

    Many thanks for your reply

    Regards

  • Is it time we shift emphasis from technological solutions to climate change & focus on the 'Human Dimension'?Is it not obvious that nature can heal..

    itself, if only left alone? Many natural parks managers do just that; seal off the area from human interference to let nature heal and recover. It is classified as 'Strict Nature Reserve"by IUCN. As technology is no match for human greed, isn't introspection & restraining ourselves more relevant than developing more technology, which caused the mess in the first place, by making it easy for a few to consume more? Since technology is only a short term quickfix which fails after a short time, isn't the real problem our addiction to material consumption & our lack of understanding about human nature? Isn't developing more technology sustaining the addiction instead of correcting it, leading to more complex problems later on, needing more complex technological quickfixes like higher drug dosages, more ground troops & equipment, (along with their debilitating side effects) in the future? Isn't this the vicious addiction circle we are trapped in? As researchers, do we merely buy more time with technology OR go to the very root of the problem, the human being?

    A lot of hue and cry is made about climate change and the environment in general. Public and private money is poured into research to study its effects on the environment, sustainability etc. Should we study nature or ourselves?

    " Our studies must begin with our selves and not with the heavens. "-Ouspensky

    Human activities have been found to have a direct correlation to climate change and its impact on the environment(I=P x A x T, the Ehrlich and Holdren equation), in spite of what some complacent sections say to protect their own self interests.

    We hardly know about Human nature. We can scarcely predict human behavior. We need to find out why we think like we do and why we do what we do and why, in spite of all knowledge and wisdom, consume more than what we need, in the form of addictions to consumption and imbalance not only ourselves but also the family, society and environment around us..
    Humanity is directly responsible for all the unnatural imbalances occurring on the planet. Yet we refuse to take responsibility and instead focus on climate change, or fool the public exchequer with a 'breakthrough in renewable energy just around the corner'. We scarcely know what drives human beings. If we had known, all the imbalances around us would have had solutions by now, given the amount of money plowed into finding such solutions. Are we blindly groping in the dark of climate change because we don't know the answers to our own nature?
    Is it not high time we focus on what makes us human, correct our consumptive behavior and leave nature to take care of climate change? Why focus effort on 'externals' when the problem is 'internal'- 'me'?
    Aren't we addicts denying our addiction and blaming everything else but ourselves?

    " We are what we Think.

    All that we are arises with our thoughts.

    With our thoughts, we make the world." - Buddha 

    IMHO, We don't need to save the World. It is enough if we save ourselves from ourselves. The need of the hour is not vain glorious interventions, but self-restraint and self-correction!

    The Mind is the Final frontier.

    Michael P. Weinstein · Montclair State University

    Humans have altered the biosphere to the extent that we have coined a new term for it, the Anthropocene, or Age of Humans.   If we don't alter our behavior, be assured that nature will take care of our follies for us.   We have initiated the 6th mass extinction on Earth, what makes us think that we are immune to the consequences of our actions?   Summarized in attached.

  • Nik Murphy added an answer in Medical Neurosciences:
    Why do I have electrodes in Scan 4.3 Cap that show maximum impedance and noise?

    I'm using Scan 4.3 and Neuroscan SynAmps2 amplifier with 64 channels. The cap was bought just over a year ago, but I already have 5 electrodes that show maximum impedance/noise. It's hard to believe that they became damage so quickly. Have you ever dealed with this problem? I can ensure you that it was not due to bad use.

    Thank you for all the help!

    Nik Murphy · Newcastle University

    How are you cleaning the cap after/before use?

    Are the sucker parts still intact for those electrodes? If not then the electrode cannot properly conduct from the scalp.

    Although losing a couple of electrodes is not ideal it can be rectified during analysis.  Make sure to remove these whilst processing the data, then interpolate them once the data is cleaned.

  • Loïze Maréchal added an answer in Kinase:
    How can I measure the activation of a kinase in a cell ?

    For example, measure the activation of SRC

    Loïze Maréchal · CHU de Québec

    Thank you !! :)

  • After storage of histopathology slides for few months, we find development of minute vacuoles throughout rendering them useless, can any body help?

    We have been facing this problem since couple of years. we have changed DPT mountant but the problem persists. The slides we have prepared in past are good even after one and a half decade. we follow the same paraffin embedding technique now but the slides does not last long (few months).

    Wolfgang H. Muss · Paracelsus Medical University Salzburg

    If you have changed from manual mounting to automatic mounting there are parameters which - if not proper -  can lead to minute vacuoles too.

    If you have moisture in your DPT mountant (BTW: I could not find the unabbreviated trivial name for it, so perhaps you meant DPX Mountant for histology??) some time after mounting vacuoles can form.

    If you have had to much pressure on your cover glass during finishing your mounting, vacuoles can form

    If you have diluted your mountant too much (and the former condition too = too much pressure), tiny vacuoles can formed too.

    I guess there are some possibilities more...so you should tell us more about the mountant you use and how you do it now and did it in the past (same person(s)??)

    Best regards, Wolfgang

  • Is the impact factor and its calculation method fair and equitable?

    Is the impact factor and its calculation method fair and equitable?
    What is the best way, to publish in journals online or manually? Is there an effect to the factor of the journals increase or decrease?
    Note that there is a lot of criticism in the way the impact factor is calculated.
    Your opinion is very important.

    Please see:

    http://en.wikipedia.org/wiki/Impact_factor

    Raheam A Mansor Al-Saphory · University of Tikrit

    Dear All

    Thank you for your opinions

    Best Regards

  • Does anyone know the maximum number of samples which we can give to sensory panellists to evaluate at a time, in a descriptive test?

    I have to evaluate yoghurt samples for six characters (i.e. Color, Appearance, Odour, Taste, Texture and Overall acceptability) using a 5 point hedonic scale. Can I use 5 samples at a time?

    Jatinder Pal Singh · Guru Nanak Dev University

    The maximum number of samples that can be evaluated at the same time are 5, as sensory fatigue can occur when excessive number of samples are presented to the panelists for evaluation. Other thing is memory recall. A better approach is to plan a design that spreads out the samples over several sessions.Usually, in affective test methods the sensory analysis the panelists are untrained, so the they should be more in number. Drinking water to remove the after taste is a good option after evaluating each sample.

  • Which is more appropriate to use: rice cultivar or rice variety?
    I am very confused about the use of term cultivar or variety for same genotype in different papers. Which should be used more accurately?
    Patrick Mckenna · Royal Agricultural University

    Generally 'variety' is considered to a taxonomic rank below species, whilst cultivar is used to denote a plant bred for agriculture or horticulture.

    There is no real agreement as to whether the correct term in taxonomy is 'variety' or 'subspecies', it depends on which authority one is using. The two are often used interchangeably in the literature. There are even instances of confusion between 'variety/subspecies' and 'cultivar' although this is less common.

    A good rule of thumb: If you are talking about wild rice genotypes use variety, and when talking about bred rice genotypes use cultivar.

    Hope this helps!

  • Dave Kahn added an answer in Polarization:
    Any idea why a polarizing beam splitter modifies the polarization properties of light that passes through it?

    Hi,

    My setup includes a horizontally linearly polarized laser beam that passes through a polarizing beam splitter and then enters a polarimeter in order to check its polarization properties. I've noticed that with some of the polarizing beam splitters I've tested the polarization elipticity value increased after passing through the optical element. This means that the output polarization is now partially elliptic and was slightly modified by the optical element.

    Any idea what can cause this behavior?

    Thanks,

    Assaf

    Dave Kahn · Annidis

    Any component of polarisation that is orthogonal to the linear component defined in the specification indicates a reduction in the performance of the PBS.  Check the specification of the PBS and then decide whether to return it to the supplier for a refund!

  • Monsur Ahmed asked a question in Tin:
    Can anyone suggest for a solution to galvanic deposition of tin (Sn) onto Silicon wafer?

     Need a chemical solution containing Tin (Sn) which will deposit onto silicon by galvanic deposition. 

  • Rezoug Amar added an answer in Control Theory:
    What are the new trends in sliding mode control?
    Does the HOSM provide good research opportunities or has it become stagnated?
    Rezoug Amar · Centre Algérien de Développement des Technologies Avancées

    observer design using sliding mode is also an interested recherche way

  • Which Information Systems Success Models would be best for my research?

    I'm about to evaluate some  new IS in an enterprise. Some are for  voluntary, and others  are for  a mandatory job environment. Understand that there are some already known models out there such as D & M IS Success models ( original and updated), TAM, and EUCS.. 

    I'll be very grateful if anybody here could give me an insight, when to use  original D&M Model, Updated D&M Model, TAM, and EUCS?

    Thanks in advance.

    Cheers,

    Hadi

    Michael Cuellar · Georgia Southern University

    Aleksandr has some good points regarding D&M vs. TAM.

    However the D&M model has notable problems in determining when and IS is successful. In particular, it ignores the socio-political aspects of success. Like all objectivist methods, it assumes that success is an objective characteristics of a project that can be measured. I would argue that success rather is a subjective evaluation determined in a socio-political process. The D&M model also has specific problems.

    It assumes that when you have "net benefits" that you have a successful IS. This is not always the case. For example, consider the Alpha NZ case in Larsen and Myers (1997) ICIS paper. The project delivered net benefits and was at first considered successful but later not successful.

    Second, it indicates that if you have the six factors then you get net benefits. The question that arises here is that there is an assumption that net benefits come from the IS and not from something else. This assumption is problematic to say the least.

    Third, this approach cannot be used until the project is completed and has time to generate benefits. Thus it doesn't help you during the course of a project.

    I've put this in a paper that I've published here and am now revising for publication: 

    https://www.researchgate.net/publication/259593652_The_Nature_of_Project_Success

  • Peter M. Bednar added an answer in Hermeneutics:
    Is there any simple explanation about HERMENEUTICS methods in Qualitative research?

    I need to develop a case study using hermeneutics method related to philosophical thinking among educators but still couldn't understand about this term and the procedure.

    Peter M. Bednar · Lund University

    There is more than one method used by researchers who are applying a *hermeneutics* related philosophy (e.g. phenomenology). There is also more than one *hermeneutic* philosophy. So there is great potential to be confused. However it is quite a significant issue to confuse *philosophy* with *method*. From a phenomenological stance *any* method could in principle be used from any philosophical point of view. Method used does not determine philosophy. Philosophy is what is being used by people to justify the relevance and appropriateness of their use of method for a particular purpose - from their point of view. So any method can be used from any philosophical point of view - what matters is that the justification of any results and conclusions will be made differently. There is really no short cut when it comes to *philosophy of science*. Either you are reflecting actively on which philosophy you are pursuing - or you are blissfully ignorant of the philosophy that you are using to guide yourself with when you make decisions and value judgements... Still whatever philosophy you are applying in your reflective thinking - philosophy and method will not be deterministically linked with each other. Especially not in the world of hermeneutics.

  • Stefano Quattrini added an answer in Doppler Effect:
    Is the doppler effect of light an actual energy shift of photons or it is only a relativistic connection of different reference frames ?

    Some authors affirm that since the doppler effect is based on energy/momentum conservation in the laboratory frame it is an acutal energy shift of the absorbed photon. A tiny part of the kinetic energy of the absorber is transformed into the electromagnetic energy of the absorbed photon, raising its frequency. The relativistic part (LORENTZ factor) is due only to the rescaling of such energies.

    Some others reply that the above view point is not correct.  Doppler effect of light, though can be drawn from the energy-momentum conservation alone, is only a relativistic effect, a matter of seeing the same photons from different view points.

    I fully agree with the first point of view.  It is quite important according to my opinion to clarify on such distinction.

    Maybe a third view?

    I wish your opinion about it.

    Stefano Quattrini · Sapienza University of Rome

    Dear Erkki (sorry for Eric),

    this discussion about energy conservation is central and of paramount importance. I'm having a sort of this discussion also in another thread, with some mathematicians who do physics giving little importance to it, not very aware of the consequences of their considerations.

    "However, there is another deep problem lurking here, viz., the Minkowski metric, which is indefinite, alters the properties of the Energy variation principle."

    What is quite difficult to demonstrate is that in an isolated system energy is "not conserved", and energy is the possibility for a system to perform a work. So far nobody managed to show that this property was infringed. 

    To Admit an extraction out of "space-time fabric" of the capacity to produce  work ,  has to be very carefully demonstrated experimentally, breaking the pillar even of the Heisemberg indetermination principle, which prevents that vacuum energy assumes a priviledged direction (entering the 4D) in quantum electrodynamics.

    The Lorentz contraction was born in order to comply to energy and momentum conservations separately. All the theories have been tested under these assumptions, and many were discarded, NOETHER'S theorem was a way to explain mathematically these conservations (momentum, angular m...) as the properties of a continuous manifold.

    Feynman himself said that the variational principle of EULER-Lagrange orHamilton-jacobi which embodies the Noether's prescription are necessary ingredients for a good theory to come out.

    That the way energy is calculated had to change after the discover of the Lorentz factor is simply due to the fact that in an isolated system the energy conservation had to be complied and the only way to make energy conservation come out, not admitting leaks of the space-time fabric,  was simply  to add changes on how energy was calculated...

  • A. M. R. Ribeiro 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 ?

    A. M. R. Ribeiro · Instituto Superior Técnico

    Just to add a couple of remarks:

    There is some discussion if the geometry affects the modal damping factor or it is just a non-linear variation of the structural damping factor with the frequency, amplitude or/and strain rate (parameters that are, themselves, geometry dependent).

    Typically, for structures (as opposed to single free-free members) most of the damping observed is due to the joints, including the clamping of a beam; in this cases, this overwhelms the material (internal) damping.

    The classical reference about this issue and probably the best is Lazan's PhD thesis.

  • Theeranun Siritanon added an answer in TOPAS:
    Can I add Kbeta in GSAS refinement?

    I collect the data using Bruker and they told us that there might be Kbeta residual. When using TOPAS, there is a function where you can add Cu Kb (1.39222A). I am now trying to use GSAS to refine the same data. Is it possible to add this?   

    Theeranun Siritanon · Suranaree University of Technology

    Thank you. I am really new to this field and only know how to use GSAS with expgui. So, to be honest, I don't really understand your suggestion related to GSAS. I think I will now try to do more refinements on TOPAS. I will come asking for more suggestions with that later on. Thanks again :) 

  • Adarsh Nair added an answer in MATLAB:
    Any matlab function to generate a large number of pseudo random sequences(Gold and Kasami)?

    i'm looking for an algorithm to get randomly a number of sets of Pseudo random requences among a huge number of generated sequences .

    Adarsh Nair · Indian Institute of Information Technology Allahabad

    I am not sure of what you are searching for by looking at your question but I think you are searching for something similar.

  • How much minimum % cell viability must a material show so that we can call it Biocompatible material?

    In MTT assay test of nanoparticles , How much minimum % cell viability a normal macrophages cell must show afetr treating with nanoparticles  so that we can call it Biocompatible material.

  • Igor Voloshyn added an answer in Dark Energy:
    Is dark energy merely an illusion?

    According to a report by Carlo Iorio and Timothy Clifton, dark energy may be an illusion. And LTb model or variations of it can be promising candidates to get rid of it. What do you think?

    Igor Voloshyn · Lviv Banking Institute of University of Banking (Kyiv)

    By the way, dynamics of 3 or 5 (I don't remember exactly) bodies in a gravitational field, it seems, is still not solved. Sorry, I don't know Hawking. 

  • Alice Brosius added an answer in Cell Viability:
    What are some good devices to effectively and quickly mince human adipose tissue?

    We routinely get between 50 and 150 grams of adipose tissue that we process for stromal vascular cells - we currently mince by hand with scissors, but it's a huge time drain and takes a long time, which may be affecting cell viability. Does anyone know of any devices to help in this process? We are considering anything and everything, from a kitchen blender to expensive tissue homogenizers.

    Alice Brosius · University of Michigan

    Carl, what kinds of tissue have you used the cheese grater on? This is one of the options we are considering.

  • Giuseppe Cotellessa added an answer in Mapping:
    What is LC data mapping?

    please, I did not inderstand the accronym LC data mapping?

    For objects nature interpretation  into images it can be useful  patent procedure.

    See:

    http://marcolarosa.blogspot.it/2013/04/il-genio-italiano-nonostante-tuttonon-e.html

    Best regards.

    Giuseppe Cotellessa

  • Igor Pastirk added an answer in Optical Fibers:
    What is happening with pulse width in time domain after propagation through optical fiber?

    How does nonlinearity change the width of the pulse (expand or shrink) in time domain, and how does the dispersion change the width of the pulse (expand or shrink) in time domain? Thank you in advance.

    Igor Pastirk · TOPTICA Photonics AG

    Re: V. Farber:

    Like with any question in science (or for that matter - in life) try to be more precise with the question before you end up getting pages and pages of answers here. People are very helpful at RG - but you should respect their time and be specific as much as possible. Web search can answer a lot; then when it can't anymore - due to very specific inquiry you might have a collective brain on RG can.

    What kind of pulse, how long/short? how intense? what fiber?etc, etc...

    Re:Alex A: I think that educational question should be here - but provided they are very specific. Therefore the answers could be too.

  • Does a measurement system exist to obtain plasma current due positive and negative ions?

    I have to measure current due positive ions with respect negative ones but I can not use a magnetic field to measure them.

    The system consist on a high density plasma thruster working over 50kV

    Javier Luis López · Pulsotron SL

    The Doppler method is a lot less intrusive and gives the speed of the particles that is right, but perhaps may not give good for accuracy measurement of the ion current because negative ion emissions must be higher. I have made some calculus for the 656nm emission of hydrogen and for speeds of 10km/s and 17º degrees of the observation line I obtain only 20nm shift

    I have added the Doppler formula in the next excel table to be uploaded to RG: "Useful formula and excel tables for plasma physics V06.xls", formula number 210:Ion speed measurement by using Doppler shift

  • In mathematics, there is no absolute truth. What kind of truths are we striving for in Physics?

    In pure mathematics there is no absolute truth [Stabler]; we invent rules then see what they prove or see what is consistent with them.  So in physics, what kind of truths are we looking for? Are we looking for absolute truths in physics?

    (Note that the premise of my question immediately contradicts itself -- saying there is not absolute truth is an absolute statement. Maybe it is not a mathematical statement, I'm not sure.  Apologies for this mess.)

    Ref:  Edward Russell Stabler, An introduction to mathematical thought, Addison-Wesley Publishing Company Inc., Reading Massachusetts USA, 1948.

    Akira  --  Perhaps you've never heard of Noether's theorem. Since we take physical systems to be independent of position and time, it results that the systems energy and momentum are conserved.