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
  • Kelly Mcgrath added an answer in Neuroscience:
    What are the details of N2A cell differentiation methods?
    I'm looking to differentiate mouse N2A neuroblastomas into cells with a more neuron-like morphology and physiology. I have read that you can do this with either retinoic acid or with serum deprivation. However, most methods are not any more clear than that. How long does either treatment need to be applied for? And are the cells then switched back into regular medium? And how long does the effect last?
    Kelly Mcgrath · University of Montana

    Once differentiated, do the cells have any properties intrinsic to a particular class of neuros? e.i. DAminergic or cholinergic?  has anyone classified these changes in terms of proteomics? Sorry to not provide answers, and only present more questions!!

  • Vanessa Meloni Massara added an answer in Railway:
    What is a suitable software for railway turnout simulation and calculating wear and stresses?

    In the name of god

    Hi dear researchers 

    what is the best software for railway turnout simulation and calculating wear and stresses in switch and crossing?

    Vanessa Meloni Massara · University of São Paulo

    Dear,

    I believe this material will help:

    http://www.ewi.tudelft.nl/fileadmin/Faculteit/EWI/Over_de_faculteit/Afdelingen/Applied_Mathematics/Mathematische_Fysica/Personeel/Emeritus/papers/doc/1987-149_wheel-rail_wear_calculations.pdf

    http://www.diva-portal.org/smash/get/diva2:9348/FULLTEXT01.pdf

    http://www.diva-portal.org/smash/get/diva2:371655/FULLTEXT01.pdf

    Regards,

    Vanessa

  • Allan Mckinnon asked a question in Tanzania:
    What were the origins of Pentecostal churches in East Africa, especially Tanzania?

    I am looking for some resources to help establish some of the earliest facts around key missionary personnel from pentecostal mission work. Can anyone help me?

  • Priyani Paranagama added an answer in Terpenoids:
    What is the best solvent system for isolation of terpenoids and flavonoids?

    I am isolating terpenoids and flavonoids from leaves of a plant, looking for hints on choice of solvent sysyems

    Priyani Paranagama · University of Kelaniya

    Olga Lock has made a good suggestion Asekunowo can try that method too.

  • Michael Altunbay asked a question in Research Papers:
    Why am I getting a feeling that RG is a one-way street?

    RG has been very dissapointing for me so far. None of my download request has been successful. Although, the document (link) is sent by the researcher, it cannot be downloaded with a message of " Unable to open the Internet site....."

    As this was not frustrating/infuriating enough, RG does not miss any chance to probe further if I want to update my research papers etc to their site.

    RG management will have to understand that this type business is not a one-way street. One cannot operate if he/she only wishes to gain. I say; get your act together, guys.

  • How can I generate the waiting time for each customer in an output file?

    I am generating one text file from one model of arrival time of 100 customers. My Arena simulation model has just one entity, process and dispose.

    My requirement is to read those arrival times for 100 customers and generate the output of waiting times for each customer in a text file.

    Mohammad Shbool · University of Arkansas

    Anuj Mittal,

    Did you use my answer above? I wan to know if this is what you were looking for! This helps me in my teaching process

    If yes, give it a like

  • When it comes to simultaneity is Einstein correct or is Dingle correct?

    Albert Einstein claimed in 1905 that a single event can occur simultaneously at different times within two inertial reference frames moving relative to one another. In 1950 Herbert Dingle argued that different times cannot be simultaneous. I have analysed this conflict by deriving the Lorentz equations using both points of view. According to this analysis Dingle must be correct. See youtube presentation of this analysis at  https://youtu.be/4XLYzhHQ64Y

    Charles Francis · Jesus College, Cambridge

    Valentin, you never stop insulting people, with your infantile and childish claims of the inconsistency of a theory you are either too lazy or too stupid to understand. Indeed you have repeatedly shown that you have no interest in understanding anything, and only post to be offensive.

  • Peiliang Cong added an answer in Recycling:
    OILY SLUDGE. How to extract oil adsorbed on sand or soil?

    Recycling of petrolium oil adsorbed on sand. How

    Peiliang Cong · Chang'an University

    Dissolve using solvtion and filtrate maybe anther method.

  • Louis Brassard added an answer in Chimpanzee:
    Have primate species other than Homo sapiens engaged in acts of aesthetic creation?

    For several years some scholars have accepted the engraved pieces of ochre from Blombos cave in South Africa, at least one of which has a geometric cross-hatched pattern, as evidence of early modern human aesthetic creation (ca. 75,000 BC). See: Henshilwood, Christopher S.; d’Errico, Francesco; et al., “Emergence of modern human behavior: Middle Stone Age engravings from South Africa,” in Science, new series, vol. 295, no. 5558, February 15, 2002, pp. 1278-1280 (http://www.sciencemag.org/content/295/5558/1278.abstract?sid=da7c3755-b2bc-4ced-93da-2c024c50b1fd, access: March 14, 2015).

    The recent discovery of similar engravings on shells on Java, from ca. 500,000 BC -that is, long before the emergence of modern Homo sapiens-, suggests that aesthetic creation evolved gradually. See: Joordans, Josephine C. A.; d’Errico, Francesco; et al., “Homo erectus at Trinil on Java used shells for tool production and engraving,” in Nature, December 3, 2014 (http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13962.html, access: March 14, 2015).

    Suggestions that chimpanzees make aesthetic decisions while painting are intriguing. See the following texts and video:

    http://www.artistsezine.com/WhyChimp.htm

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

    http://en.wikipedia.org/wiki/Congo_(chimpanzee)

    https://www.youtube.com/watch?v=uvzGV3LnWIE

    Can anybody point me toward additional studies on aesthetic creation by nonhuman primates, either in the archaeological record or among our contemporary primate cousins?

    David,

    They are a lot of book on symmetry.  When I began to be fascinated in this topic around 1994 because of its ramification in mathematics, physics, biology, decorative arts, architecture, visual perception etc, etc. , the first book I read was:

    Symmetry by Hermann Weyl

    http://1.oito.eu/Symmetry.pdf

  • Janice Cabahug added an answer in Critical Thinking:
    Critical thinking vs. truth in education?

    Many educators claim critical thinking as one of the major skills for 21st century students. Students may challenge any 'fact' to construct their own body of knowledge. 

    On the other hand, educators have to build on some truths (e.g., in maths we use axioms) in their teaching. This can be overwhelming students. How do you, as a teacher, find the right balance?

    Janice Cabahug · Touro University Mare Island

    Interesting question. It's like the chicken or the egg question, which comes first? Critical thinking can co-exist with truth in that critical thinking is more process based. Critical thinking is constructivist and relative, but has to have foundations in some type of fact, prior knowledge, etc. So for example, in math, you know that the end result should be 35 (factual), but the formulas you use to arrive at that conclusion might vary (critical thinking).

  • Open-Ended Instruction. Is it a model of teaching?

    In my opinion, a model of teaching should consist of: (1) syntax, (2) social system, (3) principles of reactions, and (4) support system. Therefore, if someone claims that open-ended instruction is one of the models of teaching, the syntax should be clear. If it is true, I don't know for sure the syntax of open-ended instruction. Is there someone who can clarify this issue? 

    Abdur Rahman Asari · State University of Malang

    OK... Thnks Anthony and Janice ...

    Based on Anthony's answer, Open Ended is used in Problem Based Learning (which is one of the models of teaching). As an entity, Open Ended Instruction is not a model of teaching.It just a part of a model of teaching.

    Based on defintion of model of teaching  If open-ended instruction is one of the models of teaching, then there should be a syntax which explains how this open-ended instruction should be implemented (step by step).

    What would be its syntax?

  • What are the qualities and attributes that determine the level of a research work (Journal article, conference proceeding)?

    It is important to decide about the targeted level of any research work before doing it. I mean to be knowledgeable about the outcomes and contributions needed for work to be considered for a peer reviewed journal, or to be sufficient for a conference proceeding.

    In my opinion, this helps in planning and allocating time and tasks

  • Jia Zhao added an answer in Microchip:
    How to process data for capillary electrophoresis on microchips?

    I am new to microfluidics. Now I am working on capillary electrophoresis on microchips. After extracting data (intensity vs time) from video, I cannot get very good Electropherogram. How to substract the noise and normalize the intensity? Thanks in advance!!

    Jia Zhao · The Ohio State University

     Thanks for the reply, Dammika. I have tried to subtract the noise got from averaging the area before the first peak, and attached is the figure I got. It still has a lot of noises. BTW, I don't have unused primers, so my first peak is my product peak. Thanks.

  • Peter Raymond Smith asked a question in Australasia:
    Mass spectroscopy analysis of plasma steroids, Australasia?

    I'm looking for a lab which offers chromatography/mass spectroscopy analysis of steroid (testosterone, estradiol, progesterone) levels in plasma. Planning to use pregnant sheep samples where testosterone and estradiol have proved problematical by RIA and/or ELISA. Any help appreciated

  • How do I estimate the shock wave pressure in a solid?

    When an intense laser pulse is focused inside the solid, especially glass, a strong shock wave will be excited from the focus. how to estimate the pressure according to the velocity of shock wave front?

    Manyalibo J. Matthews · Lawrence Livermore National Laboratory

    I concur with Maxime.  In Zeldovich you'll find an expression for a point explosion which might be useful, where the shockwave position increases as R=(2.4E/rho)^0.2*t^0.4 where rho is density, t is time and E is the energy released. 

  • Kim Rez asked a question in Suicide:
    Were any psychological impacts of kurt cobain's suicide?

    Were any psychological impacts of kurt cobain's suicide?

  • What can you do as a teacher, researcher or a simple individual against marine defaunation: animal loss in the global ocean processes?

    Dear All,

    The decline of water organisms arrived a level which threats our existence. McCaulay et al. (2015) prepared a fine paper describing this situation.

    Have you experienced similar phenomena in marine ecosystems?

    Are you satisfied with this deterioration?

    What can you do as a teacher, researcher or a simple individual against these processes?

    Marine defaunation: Animal loss in  the global ocean

    Douglas J. McCauley,* Malin L. Pinsky, Stephen R. Palumbi, James A. Estes,
    Francis H. Joyce, Robert R. Warner

    Science 16 January 2015:    Vol. 347 no. 6219   DOI: 10.1126/science.1255641

    http://www.sciencemag.org/content/347/6219/1255641.full

    Summary

    “Marine defaunation, or human-caused animal loss in the oceans, emerged forcefully only hundreds of years ago, whereas terrestrial defaunation has been occurring far longer. Though humans have caused few global marine extinctions, we have profoundly affected marine wildlife, altering the functioning and provisioning of services in every ocean. Current ocean trends, coupled with terrestrial defaunation lessons, suggest that marine defaunation rates will rapidly intensify as human use of the oceans industrializes. Though protected areas are a powerful tool to harness ocean productivity, especially when designed with future climate in mind, additional management strategies will be required. Overall, habitat degradation is likely to intensify as a major driver of marine wildlife loss. Proactive intervention can avert a marine defaunation disaster of the magnitude observed on land.”

    Why is marine wild life so essential for us?

    “Marine defaunation is already affecting human well-beinginnumerouswaysbyimperilingfood
    sustainability, increasing social conflict, impairing storm protection, and reducing flows of other ecosystem services (64,65). The most conspicuous service that marine fauna make to society is the contribution of their own bodies to global diets. Marine animals, primarily fishes, make up a large proportion of global protein intake, and this contribution is especially strong for impoverished coastal nations (66). According to the U.N. Food and Agriculture Organization (FAO), 40 times more wild animal biomass is harvested from the oceans than from land (67). Declines in this source of free-range marine food represent a major source of concern (65).”

    Gregory D. Turner · West Chester University

    Points well taken!

  • Is Chalmers' so-called "hard problem" in consciousness real?

    In his 2014 book "Consciousness and the Brain: Deciphering How the Brain Codes Our Thoughts" Stanislas Dehaene wrote "Chalmers, a philosopher of the University of Arizona, is famous for introducing a distinction between the easy and the hard problems. The easy problem of consciousness, he argues, consists in explaining the many functions of the brain: how do we recognize a face, a word, or a landscape? How do we extract information form the senses and use it to guide our behavior? How do we generate sentences to describe what we feel?

    “Although all these questions are associated with consciousness,” Chalmers argues, “they all concern the objective mechanisms of the cognitive system, and consequently, we have every reason to expect that continued work in cognitive psychology and neuroscience will answer them. By contrast the hard problem is the “question of how physical processes in the brain give rise to subjective experience … the way things feel for the subject. When we see for example, we experience visual sensations, such as that of vivid blue. Or think of the ineffable sound of a distant oboe, the agony of an intense pain, the sparkle of happiness or the meditative quality of a moment lost in thought … It is these phenomena that poses the real mystery of the mind”."

    Stanislas Dehaene's opinion is "that Chalmers swapped the labels: it is the “easy” problem that is hard, while the “hard” problem just seems hard because it engages ill-defined intuitions. Once our intuition is educated by cognitive neuroscience and computer simulations, Chalmers’ “hard problem” will evaporate".

    Personally, I agree with Stanislas Dehaene's opinion.

    Bernd Schmeikal · University of Vienna

    Yes, 'http://newempiricism ..' is important. “… each of these steps is a physical event so there is no information without representation as a state in the real world”. That’s true, and it doesn’t rule out philosophy. The Eleatic Greek philosophy knew that from a meaningful statement we can go over to something in the real world. Parmenides postulated that we can work back from true sentences to real things, that is from ‘f(a)' is true’ there follows ‘a has being’ or briefly ‘a is real’ or ‘a exists’. Such a transition from logic to ontology can be considered as a first step towards representation. As Arnold replied “The existence of information implies the existence of a complex 
physical system [..]”. Yes, of course. Arnold’s answer is elaborate. It requires a lot of thought and conversation to become sociologically mandatory. (It is not relying on Yoga, Kundalini, Prenatal Psychology or Psychiatry, and I don't regret it.)    Good night, I hope you allow me to sleep.

  • How can I detect fetal hemoglobin in maternal blood by flow-cytometry?

    I want to study the effect of method of delivery on fetomaternal circulation, the ideal indicator is the fetal RBCs in maternal blood, by flow cytometry I found a problem that the expression is high  

    Rosemary L Sparrow · Monash University (Australia)

    It is really important to use high quality reagents - best to start with a commercial  anti-fetal Hb test kit if you can afford it. Use a PE-conjugated anti-HbF, as PE gives a much brighter signal than FITC which is important for low abundance cells such as fetal cells in maternal blood.  Also you may need to keep in mind that mothers who have certain hematological conditions or inherited traits may have circulating F cells (i.e. red cells that contain lower levels of HbF than found in fetal red cells). 

    Regards, Rosemary

  • Carl Alexander Sorensen added an answer in G*Power:
    How do I run a power analysis on a moderated mediation model (Hayes' Model 7)? Is this possible with G*Power settings does anyone know?

    Model image attached. Many thanks.

    Carl Alexander Sorensen · University of South Carolina

    I have done this in R as well! Its totally free and open source, but it is another thing to learn. I will attach some example code (from Lee VanHorn at U of SC) if you want to have a look. Let me know if you have questions (or if I gave you the wrong file)!

  • Yurgos Politis added an answer in Higher Education:
    Can anyone suggest some good references on Internationalisation?

    I am trying to come up with a suitable definition/meaning of Internationalisation in the context of higher education in small island states.

    Yurgos Politis · Dublin City University

    Dear Fazeela,

    some more reading material for you

    Best of luck

  • Lumila Menendez added an answer in Collecting Data:
    Dooes anyone have any idea on how analyzing ecological data from different sites/indicators?

    I would like to analyze data from different LTER sites in order to evaluate the effect of climate change on different ecosystems. The problem is that each site collected data with different study design and with different response variables (diversity of different taxa, variations in snow cover, biogeochemical cycles, ecc.).

    Lumila Menendez · National University of La Plata

    Try with geostatistics/spatial analyses. They are very useful because biological data are always spatially structured.

  • Dean Whitehead added an answer in Anthropology:
    Could anyone recommend a reliable publishing house?

    I have funds for an anthropological book, want have good quality and must keep 5 months time limit.

    Dean Whitehead · Flinders University

    Dorota - there are many good quality, established publishing houses that you could aim for. The main ones are Elsevier, Wiley-Blackwell, Palgrave-MacMillan, Sage, Oxford University Press, Cambridge University Press etc. However, not everyone 'enjoys' or wants to publish with large corporate publishing houses - especially on ethical or 'green' grounds. On the other hand, they can be more prestigious and are better equipped to 'internationalise' your book - and market it more widely.

    Even though you have existing funds though Dorota - it's not as easy as 'just applying' to write a book. It's a competitive environment and you have to go through a robust proposal submission process that, not only takes time (which 5 months is not long - most texts take up to 2-years to get from proposal to publication) - but has to be agreed and accepted by the publishing editors.

  • Hamid-Titilope Oladunjoye asked a question in MASW:
    How does Shear wave velocity related with MASW? How can it be determined?

     How can it be determined? 

  • Ron Reade added an answer in Transcriptome:
    Is it possible to perform whole transcriptome amplification with cDNA as input?

    I need to amplify the whole transcriptome of some cell culture experiments for downstream analyses (qPCR and Sequencing). From the cell culture experiments of interest only smal amounts of cDNA are left. No cells, no RNA.

    The cDNA was once reverse transcribed from total RNA using random-Hexamere Primers and Super-Script-II reverse transcriptase.

    Sadly, all the available protocols I found use RNA as template for WTA.

    Is there a protocol to amplify already transcribed cDNA?

    Thanks for answeres in advance!

    Ron Reade · Agriculture and Agri-Food Canada

    Hi Alex,

    Somehow I have ended up following this question unbeknown to me, so I get an email update every time someone tries to answer your question.  I know the answer that you want to hear is that you can do it, and here is the magic tool, however this is not the case unfortunately. If your cDNA is not abundant and doesn't have good genome coverage then you are not going to get good results with WTA or qPCR. Basically both these techniques rely on having good quality starting material in order to get good results. If you try either of these techniques on your material, I have not doubt that you will get some results, but it will be highly unlikely that your results will be accurate, and therefore, what is the point of you spending your hard earned time and money. If you have any more RNA for any of your trials, I would start over with that...If not, save yourself some serious grief, and a bunch of money and cut your loses. I highly recommend not using SSII for your qPCR's, as there are now much better enzymes out there that will give you more even coverage of your genome for qPCR. The SuperScript VILO kit works very well for cDNA synthesis for the purpose of qPCR if you want to stick with Life Tech.

    Good Luck

    Ron

  • Are vernacular names a clue to scientific identity of plants?

    No doubt vernacular names are useful in identifying the plant scientifically but it is not always possible since a single vernacular name may refer to different plants in different area. Moreover a single plant is variously named by different community/tribes.

    Please provide your valuable suggestions.

    Narayanan Nair Mohanan · Jawaharlal Nehru Tropical Botanic Garden and Research Institute

    In some cases, it forms a clue. A good example is of Sida species. Sida rhomboideae is known in sancrit as 'Bala'. Sida cordifolia is  known as 'Athi Bala'. Surely the plant names with suffix bala probably is a Sida species.  The plants of Ocimum genus  are known as 'Thulasi' in Malayalam.  Ocimum tenuifolium is called 'Krishna Thulsi', Ocimum basalicum as 'Rama Thulasi' and Ocimum grattisimus as 'Kattu Thulasi'. The term Thulsi gives a clue that it is a n Ocimum species.

  • Jan Urban added an answer in Astrocytes:
    Do you know any good computer program or other methods to evaluate the dimension of a cells?

    In particular I have astrocytes cells. Thanks in advance

    Jan Urban · University of South Bohemia in České Budějovice

    Try to ask this lady

    https://www.researchgate.net/profile/Renata_Rychtarikova

    she is doing information and dimensional research

  • Jan Urban added an answer in Nominalization:
    How to evaluate clusters in clustering mixed data?

    I want to do clustering and evaluating the clusters.I have mixture of nominal and discrete numerical data. I did clustering and now i want to use some useful indices to choose the best number of clusters. which of the  internal indices i should use? I mention again that the data are mixture of nominal and discrete numerical data. Thanks

    Jan Urban · University of South Bohemia in České Budějovice

    One of the way, but time consuming, is to try different amount of clusters. For each set of n clusters evaluate the inter-classes variance, and between -class variance. Then plot these variances as a function of n (amount of clusters). There should be some optimum in the way minimal intra class variance and maximum of inter class variance.

  • Second harmonic generation of crystals?

    i grown the crystals of inorganic materials doped with amino acids viz threonine, basically my material have applications in nonlinear optics. so for that ideally my materials should behave like nlo materials and it should show second harmonic generation. when i take second harmonic generation of my grown crystals which are doped with amino acids so i found that the SHG efficiency is to be decrease rather than increase. so please tell me what are the reasons behind that.

    C.G Treviño-Palacios · Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE)

    Jaudeep.

    The problem you are having more likely has to do with nonlinear conversion length. The best SHG is obtained when you fulfill phase matching conditions. To increase the signal you should find the phase matching conditions in either angle or temperature, or determine the optimum length for the xtals to maximize SHG. If the xtal is larger than the NLO length the signal does decrease rather than increase if phase matching is not achieved. 

    When you alter the material there is morphological change in the material and the optimum conditions change. So when doping with the amino acids more likely you have a different material and the optimum conversion conditions do change with respect to with the pure material. Not strange at all.

    Look for the Kurtz powder test (Kurtz Perry Journ Appl Phys, 39,1968, 3798) which is used to determine the capabilities of new materials. Maker fringes technique (Maker, Terhune et al PRL 8, 21 1962)  or any wedge technique could also prove useful. Then characterizing the material structure to find which tensor elements are active, meaning in which directions and polarization you observe SHG.Good luck with the characterization

  • What is the physiologic explanation for hypocholesterolemia after trauma or acute injuries?

    In trauma and infection the PCSK9 (inhibitor for LDL receptor) is increased. Therefore we expect increase in plasma LDL level, nevertheless there is reduction in LDL level.

    Abu-Eid I Sameer · Medical University of Vienna

    I think we have many explanation: 

    Blocking of PCSK9 by SAA

    Clearance of ox. LDL by macrophages

    Shifting of cholesterol to provide cholesterol bi-products. but this factor unlikely as the level of PCSK9 is high which will reduce the LDL receptor.