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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  • If a crystal ball could tell you the truth about yourself, your life, the future or anything else, what would you want to know?

    Knowing ourselves is one of the major goals of our lives. Ancient Greek  considered it the utmost, ultimate target. Different branches of Sciences tried and partially succeeded to give certain answers. Spirituality offers also a lot, probably quite more than science. Our aspirations, prospects, perceptions, deepest hopes and accomplishments are mixed together in an ineffable blend, we use to call life.

    Sharing your thoughts on this quest would be an honest travel into ourselves, without indiscretion, but with the aim of giving each to another the very essence of our being.

    Douglas R. Daugherty · University of New Mexico

    Dear Roland,

    There is only one question I would like the crystal ball to answer. 

    As I die in the last seconds of consciousness I would like to know if I had been honest with and to my self and others. 

    This is the answer I would like to know just before I die.

    Douglas

  • What are the most important prognostic factors for patients with colrectal CA and liver metastaisi?

    What are the most important prognostic factors for patients with colrectal CA and liver metastasis?

    Any radiological and blood markers.

    Alexander Julianov · Trakia University

    Agree with Maximilian. Just to add also the N-stage of the primary rectal cancer. For example if you look at the survival rates of N+M0 rectal cancer you will be surprised to find that it is worse than the survival of patients with solitary liver mets and N0 of the primary.

  • Harald G. Dill added an answer in Mineralogy:
    Calculation of Individual mineral magnetic susceptibility using bulk mag sus and mineralogy data?

    Hi All

    I have bulk magnetic susceptibility (MS) for 30 rock samples. I also have detailed mineralogy data using XRD. Can I simply calculate the individual mineral susceptibilities by a minimization function?

    Is it right to say weighted (or volume) average of individual  susceptibilities is equal to bulk susceptibilities? What are the assumptions?

    Harald G. Dill · Leibniz Universität Hannover

    Dear Mr. Saidian,

    how did you determined and measure your susceptibility data and what was the approach taken to precisely quantify the mineral composition of your rock samples? Both parts of the equation are crucial. Apart from that, the type of magnetic strength (e.g. ferro-magnetic...) should not be cast aside either.

    Best regards
    Harald G. Dill

  • Hugh Lachlan Kennedy added an answer in PID Control:
    How to design PID controller for autonomous flight using IMU sensors?

    While building a quad-rotor I am in need of PID controller which deals with six inputs

    x-axis, y-axis, z-axis and three associated angles

    Hugh Lachlan Kennedy · University of South Australia

    Could you start by manipulating only one variable at a time and design a different controller for each (SIMO) case? This would greatly simplify the problem.

    I am told that when you are driving a car on an icy road and you find yourself sliding sideways, you should hit the break or turn the wheel, but not to do both at the same time!

  • Should a Disaster Medicine be part of Curriculum in Medical Schools ?

    Should Disaster Medicine be part of Curriculum in  Medical  Schools ?

    Gamal Abdul Hamid · Aden University

    Dear Ishag

    More than 50% of  medical schools in the world does not teach this topic. 

    I agree with you the DM Should  be part of Curriculum in Medical Schools. 

  • Hayder Dibs added an answer in GRASS GIS:
    What kind of techniques can be used to simulate a very large-scale scene of earth surface, including all the trees with leaves?

    In remote sensing, we use satellite to monitoring earth surface, could we develop a software to simulate this process, what technique can be used to represent the earth surface with explicitly described trees and grasses

    Hayder Dibs · Putra University, Malaysia

    could you provide more details

  • Can Bacteria (e.g. E.Coli) take up small non-coding RNA from their environment?

    For a small play of thoughts. I was wondering if bacteria, despite their complexe cell membrane-cell wall structures is capable of taking up miRNAs from its environment. Even if it doesn't have effects on the cell itself (as there is no RISC-silencing in Bacteria). What do you think? Is miRNA taken up in bacteria?

    Thank you already

  • Helen Chuter asked a question in Academic Psychology:
    Does anybody have any guidance to services for Learning disabilities, within Employment in the United Kingdom?

    I am seeking Academic Psychological review listings and individual Academic opinion through Journals, regarding barriers and issues in the UK.

  • If you have many publications, how do you list them all in a 2- page CV?

    I don't have many publications yet, but I wonder how to fit many publications in a CV? Do you provide appendix or something for the publications?

    Jerónimo Carmelo Garcia-Romero · University of Malaga

    There is no universal rule for this. During the early stages can you put all the publications made, but when there is a considerable amount is usually put first the most importants (5 to 10) in the last few years and following then only the total number of publications, grouped and sorted by time period and/or JCR quality.

  • How soon can the demyelinating process start in mild traumatic brain injury?

    Traumatic brain injury, even in its mildest form, is known to result in degenerative processes including demyelination and dysmyelination of the axons over time. The shearing and tearing of the axons (primary injury) due to the acceleration and deceleration force of high velocity impact would also normally trigger off the secondary injury cascades. This includes the synaptic deregulation, cell death and axonal degeneration.  

    But how quickly does these processes start (especially the demyelination of the axons) in patients with mild TBI? I am of the opinion that it will take at least a few days or weeks before such degenerative process starts. What are your thoughts?

    Vigneswaran Veeramuthu · University of Malaya

    Well, Chandramouli. I am pretty sure that you are aware of the fact that demyelination ≠ MS., although the former is the trademark of MS and is often wrongly equated as MS. The term in itself is generic and is in reference to the loss of normal myelin surrounding the axons in CNS. There are few well known cause factors to demyelination besides inflammatory process (again inflammation is not limited to MS, and is also seen in TBI). Among the other known factors to cause or lead to demyelination are : infective disease (PML, HIV encephalitis ), toxic (chemotherapy, central pontine myelinolysis), metabolic/genetic (leukodystrophies) and ischemia.

  • Ghazanfar Sultan added an answer in Ethyl Acetate:
    How can I undo the effect of methanol in compound separation?

    I used methanol and Ethyl acetate in 20:80 ratio which result in blockage of solvent flow in Column Chromatography, when doing separation of compounds in Plant leaves........

    How can I get rid of this methanol blockage?

    Ghazanfar Sultan · University of Karachi

     My second suggestion is that,
    Perform solvent extraction with less or non-polar solvents (immiscible with methanol).
    compare both the extracts (which remains in methanol and those which go into less polar solvent) on TLC.
    then decide, how to run the column.

  • Shane Vontelin van Breda asked a question in MDR-TB:
    What could explain the decrease in CFU/ml for my control during a time-kill analysis?

    I am working MDR-TB and performing a time-kill assay. I use 1 x 10^5 CFU/ml cells from 7H10 OADC agar (~14 days incubation) and inoculate them into liquid culture (Sauton media). I then monitor CFU/ml on treatment days of 0,1,2,3 and 6 using 7H10 OADC. I noticed that my control MDR-TB have a gradual decrease over the days i.e, with regards to log10 CFU/ml, 5.09, 5.27, 5.20, 5.05 and 4.64. Comparing day 0 to day 6, there is difference of 0.45. Statistically, there is no difference between the control and RIF+INH treatment, but a difference for the peptide I am testing. 

    I would like to know if I can still use these results and if the decrease of my MDR-TB control is something natural.

    Before I got to the time-kill assay, I was using the microtiter Alamar Blue assay and by 6, the MDR-TB control was sufficiently changing Alamar Blue from blue to pink indicating sufficient growth.

    I also performed the assay using H37Ra and there was an increase in growth over the six days.

    I really hope someone can shed light on this issue?

    All experiments were conducted in triplicate and in depend of each other.

  • Zbys Fedorowicz added an answer in Bangladesh:
    Are there any option to learn systemic review and meta analysis?

    I am from Bangladesh. There is no such expertise and option to expose to systemic review and meta analysis. We are still naive to those procedures! Are there anybody doing that and promoting such!

    Zbys Fedorowicz · The Cochrane Collaboration

    Try here http://www.cochrane-sacn.org/

  • Would you kindly join me in wishing a happy birthday, and pay homage to our dear RG friend LJUBOMIR JACIC?

    i just remembered that our dear friend Ljubomir was born on the 28th of March, a few years ago.

    I pay tribute to an inteligent, sensitive and sensible sweet adorable Serbian.

    You, dear sir, are a very special person, that I feel honoured to have met, and  thank you for letting me be your unconditional admirer !

    (I do hope that Î got the date right.... If not, please consider this a singular extravagant note of friendship, )

    Yours, truly, with warm respects !

    Maria

    Maria Bettencourt Pires · New University of Lisbon

    Thank you for support, dear Sarwan.

    Yes, we must take risks, if and when we do things for Love. And true honest human friendship with admiration is well worth taking risks for. 

  • Mohammad Beik added an answer in Electropolishing:
    Can I use pulse electropolishing for resharpening?

    I want to resharpening a cutting blade but as you know electropolishing removes sharp edges.

    Mohammad Beik · Sharif University of Technology

    Complicated shapes of my cutting edge doesn't allow me to have a mechanical grinding process, but about laser treatment, I don't know. I will search about it.

    Thank you for your response.

  • Hein Van Gils added an answer in Biological Control:
    What are your thoughts on using Biological control as a countermeasure against invasive alien plants?

    The "enemy release hypothesis" is an often documented mechanism by which alien plants become invasive. There are opinions of using native enemies (may be modified) against these weeds in invaded ranges? Are there examples where such control strategies have worked? And is there any future for the approach

    Hein Van Gils · Min of Environment & Tourism, Namibia

    An old and well cited case is the alien parasitic moth controlling an invasive alien Opuntia in South Africa; this represents the only case of near total control among the many invasive alien plants known in Southern Africa. However, here in neighbouring Namibia the cactus is spreading relentlessly. Obviously, effective biocontrol, or other control, of invasive aliens is rare.

    A test case of Chromolaena control is shortly described in the attached; although optimism prevailed a decade ago, success seems still illusive.

    Elimination of invasive plants seems treating the symptoms to me; the disease, if any, is the rapid and widespread creation of open habitats and access for dispersal agents. Treatment of the disease could mean avoiding the creation of open ground and canopies, re-vegetating open habitats with indigenous plants and dispersal (e.g. access) control.

  • Is there any FLUENT UDF macro to replace the new mesh in each time step?

    I am trying to simulate a model in FLUENT that the geometry shape is varying by time. I was wondering can I generate different geometry/mesh each time step and subsequently replace the new mesh each time steps?  In fact, in the dynamic mesh events, there is option can manually define to replace the mesh in given time but I want to know can I use a UDF to do it automatically (i.e, load the new prepared geometry with new mesh each time step)?

    Siamak Nezami Doost Alamdari · Swinburne University of Technology

    Hi Belkacemi, I am grateful for your response. As you mentioned, one approach to solve the boundary deforming problems (or FSI problems) is the coupled FSI (couple the CFD and structural solver by using the ANSYS Workbench), but it is very difficult to employ in high deforming problems such as the heart or heart valve (The solution is very unstable due to the low elasticity of the solid part). FYI, I am familiar with this approach and I simulated graft and stenosis artery by using the coupled FSI before. However, the alternative approach is the geometry prescribed method that only the fluid domain is solving by defining the deformation of the fluid-solid interface as the moving boundary (By using the ALE formulation). I am trying to use this approach, so I need to prescribe the motion of the wall to the solver. Antonio proposed a good suggestion but it needs to develop a complex UDF (reading the boundary from external file), however I will try to do it.

  • Shrish Shukla added an answer in OpenFOAM:
    Can I run a plain diffuser simulation with RANS/LES?

    In short, I am investigating flow separation in a plain diffuser by openFOAM. At first I have use K-Epsilon model but near wall separation was no so good to compare with experimental data. Then I got suggestion to apply k-omega SST model with extended diffuser section and maintain y+ at a certain values. History is here: https://www.researchgate.net/post/What_are_the_key_points_of_plain_diffuser_flow_simulation_in_openFOAM_by_k-omega_SST_model

    In that thread I received huge helping hand and I am grateful to them. In k-omega SST model, upstream profiles (straight section) were in good agreement with experimental data as well as 1/7 law of turbulent flow. But in diffuser section, specially in inclined section expected separation was not as expected as found in experiment.  In this regard RANS/LES may be a alternative choice. My desktop has limited capacity:

    core i5 64 bit with 8GB RAM. For RANS/LES, 3D mesh may be necessary, is it fruitful to do so with this capacity of PC? Or is there any other key point that I don't have think yet to get better results by k-omega model. Please help me to overcome this problem.

    Best regards

    mukut

    Shrish Shukla · Indian Institute of Technology Delhi

    Hi Mukut,

    I would like to mention some points which based on my previous work experience on diffuser simulation. I agreed, that RANS  have certain limitations hence its limited use for the turbulence flow study. However, it can able to give an overview of the flow field at less computational cost. Hence at limited computer resources you should go with k-epsilon RNG model with swirl flow corrections and to resolve the flow across wall use specific wall treatment. You can able to achieve the good agreement with application of wall treatment.

    Good Luck

  • Muhammad Iqbal asked a question in Podcasting:
    How can podcasting be integrated into a language class?

    Internet is thriving with various podcasts. Very few language teachers are using this technology in classrooms.  We intend to explore the ways and means to make use of this fabulous resource to teach English as a foreign or a second language.  The use of technology obviously enhances the motivation level.  Those who are engaged with Computer Assisted Language Learning (CALL) as subject can benefit us a lot in this respect.

  • Chakravarthi Kanduri added an answer in STRING:
    Are there alternatives to STRING and STITCH databases?

    Just wondering if anybody else is having problems to load the string/stitch webpage.

    http://stitch.embl.de/

    http://string-db.org/

    If so, could you recommend another alternative?

    Thank you so much!

  • What's new in pancreatic anastomosis?
    There are many traditional kinds of pancreatic anastomosis, do you use some new methods?
    Alexander Julianov · Trakia University

    Thanks Tobias!!! Many people await the results of this trial.

  • Abdelhay Ali asked a question in Energy Consumption:
    How can i measure energy consumption in wireless sensor node (nRF24L01)?

    Dear All, i want to measure energy consumption in nRF24L01 (Wireless Transceiver Module) and measure bit  error probability.

    Thanks in advanced.

  • Nafaa Shebani asked a question in Rain:
    One-minute rain rate ?

    I would like to convert the rainfall data to  one-minute rain rate ?

    Thanks for all

  • How can I perform microbial interference analysis?

    I have sequencing data of a microbial community I would like to perform interference analysis to obtain an image of the different microbial proportions and the relationships between the different microbes. Which program can I use to conduct such analysis?
    Many thanks, 
    Tine

    Tine De Ryck · Ghent University

    Hi, 

    Thank's for the answer. I'll check the possibilities of FactoMineR as I didn't try that one yet. 
    The main purpose is to have a clear image concerning the different relations in my dataset. Something similar of what I want is depicted in the paper of Faust and Raes (http://www.nature.com/nrmicro/journal/v10/n8/fig_tab/nrmicro2832_F4.html) in Figure 4 or in the figure attached.
     

  • Narasim Ramesh added an answer in Scilab:
    Can someone suggest a reference or post a simple numerical problem which compares Riemann and Lebesgue integration of ODE's?

    Sometimes it is stated that Lebesgue integration is better , but there seem

    to be no algorithms which can be incorporated in Scilab etc ..it would be useful

    to have such algorithms.

    Narasim Ramesh · Sri Jagadguru Chandrasekaranathaswamiji Institute of Technology

    Thank you Peter T Breuer  , for  your nice clarification  but  what I meant by "better" is precisely that it might be computationally advantageous which seems to be so in the example that is found in the reference..above. thank you once again for your patient and valuable reply...

     Cheers

  • What book do you suggest to learn Bayesian statistics?

    i need examples and Bayesian statistics aplicaions

    Diego Casadei · University of Applied Sciences and Arts Northwestern Switzerland

    Hi.

    To _learn_ the best book is "Bayesian Theory" by Bernardo and Smith.  To _use_ most references above are OK.  I would add "The Bayesian Choice" by Robert as it deals with both aspects.

  • Eko Prasetya asked a question in Lysis Buffer:
    How to Extraction DNA filamentous actinomycetes?

    How to extract DNA from filamentous actinomycetes?
    I am using Kit Extraction DNA Genomic DNA Purification Kit GeneJet
    I am using a Tris-HCl, EDTA, Triton X-100, and Lysozym as lysis buffer.

    but do not get good results

    Thank you for Answers

  • Kaleem Ullah asked a question in Semiconductor Physics:
    What should be done for becoming the Emily Wolf or Max Born????

    I changed the filed in Physics from Semiconductor Physics to Optics(Nano-Resolution Optics). Now what should i do to become good in Optics??? My which areas of physics should be Powerful??? Life is learning so i can take open courses kindly share your experiences????

  • Derek Hodgson 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?

    Derek Hodgson · The University of York

    Louis, Dilthey expresses perfectly simulated empathy, which arises from the mirror neuron system and theory of mind. These factors seem to underwrite the propensity to see the world from another's perspective that allows one to appreciate pictures in various situations.

  • Why does dilution of homoeopathic medicines enhance their potency? Is this not against scientific phenomena?
    I have been told by homoeopathic practitioners that dilution and potency of homoeopathic medicines is inversely proportional. This means the higher the dilution the more potent the medicine will be and vice versa. I have doubts which may be due to my bias because personally I did not find any experience of homoeopathic medicine effective.
    Salvatore Chirumbolo · University of Verona

     https://www.youtube.com/watch?v=YiwaGnj8kPU