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  • 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?

    Subhash C. Kundu · Guru Jambheshwar University of Science & Technology

    Truth is fact. Any truth/fact may be in specific context. Knowing fact  is not development of knowledge. Giving reasoning and challenging that truth by analyzing pros, cons, and further reshaping the fact in changed circumstances -- is critical thinking and development of knowledge.

    Students those are critical thinkers may challenge the old fact and move towards redefining the fact  -- it indicates the continuity of logic -- philosophy -- new direction.

  • Nitika Grover added an answer in Porphyrins:
    How beta nitro of porphyrin can be converted into amine ?

    i have tried with SnCl2/HCl but always end up with precursor.  can I use Pd/C or any other procedure ? pl suggest me. 

    Nitika Grover · Indian Institute of Technology Roorkee

    Daniel thanks for your suggestion but my substrate is not soluble in ethanol  

  • Jennifer M. Giddens added an answer in Suicide:
    Were any psychological impacts of kurt cobain's suicide?

    Were any psychological impacts of kurt cobain's suicide?

    Jennifer M. Giddens · Tampa Center for Research on Suicidality, Tampa FL

    It might be helpful if you were more specific in your question.  I'm sure there were psychological impacts to the family and close friends of Kurt Cobain when he killed himself.  I suspect there were some level of psychological impacts on fans of his when he killed himself.  However, based upon your question, I don't know what group of people you are referring to in your question.  Do you mean "were there any psychological impacts of Kurt Cobain's suicide to anyone in the world?" or "were there any psychological impacts of Kurt Cobain's suicide to those that knew him personally?" or "were there any psychological impacts of Kurt Cobain's suicide to the fans of his music?" or are you referring to some other group of the world population?

  • Can anybody suggest a transcriptional promoter sequence active in Agrobacterium tumefaciens, other than Nopaline synthase promoter?

    For testing the expression of a protein in Agrobacterium tumefaciens cells, I would like to replace a common 35S::GUS cassette with another carrying an agrobacterium-specific promoter. NOS promoter is already in the vector for the NPTII expression, thus I am looking for a different one. Any suggestions? Thank you in advance for your kind support. Fabrizio

    No First Name Sudarsono · Bogor Agricultural University

    I would agree with Yuriy comment, eventhough Nopaline syntase (nos) gene come from Agrobacterium, it is not necessarily actively express in the bacterium. The nos gene is a eucaryotic gene and the nos promoter will actively transcribe transcription unit in the eucaryotic cells (i.e. plants). That is why the Agrobacterium need to transfer the nos gene into plant cell to synthesize nopaline.

    Unless you have specific objective to specifically express the protein in Agrobactecterium, for protein expression in bacteria - I would not use Agrobacterium but use standard bacterial expression strain commercially available. It already has a number of appropriate promoters for expression purposes.

    I hope I am not mistaken about the question and given the wrong answer. Good luck...

  • Jacek Hoffman added an answer in Laser Welding:
    Can deep penetration welding occur in the process of laser welding thin plates about 1mm?

    I'm trying to weld a 1mm steel sheet with Nd:YAG laser for following forming. Considering the effect of  the cross-section shape of the weld, I want to change the welding mode from general welding mode to deep penetration welding. According to previous studies, deep penetration welding is invented for thick plate. Now I doubt whether we can change welding parameters to change the weld shape of thin plate.

    Jacek Hoffman · Institute of Fundamental Technological Research

    Even at my very limited level of knowledge (A-1) Chinese language and characters are fascinating. I have several thick volumes and more thin booklets of Chinese calligraphy.

    So best wishes to you 文虎.

  • Dr.Chandrakant Naikodi asked a question in Hacking:
    What are hacking features of Java?


    Many java applications are hacked by hackers, typically which scenario and features of Java does loop holes? 

  • jean claude Dutailly added an answer in Probability:
    What is the relationship between randomness and probability?

    Are randomness and probability independent of one another, or does one depend on the other, or are they different expressions of the same thing?   

    Probability has a clear definition in mathematics : this is a measure on a set such that its value for the whole set is 1. It does not assume anything about randomness or a temporal ordering of events. We can have many different probabilities on the same set, but they must follow well defined rules.

    As for randomness it is relative, estimated with respect to an order or regularity expected a priori. For instance the height of people is random but less if you restrict to some subpopulations, by sex, ethincity, generation,...This gives some curious results :if you pick a up a number randomly, there is a great chance that it is an integer, and a certainty that it is a rational, even if the set of rational numbers has a zero measure in the set of real numbers.

  • Can anyone recommend some literature on energy efficiency assessments of historical buildings?

    Dear colleagues,

    I am performing a literature review on the energy efficiency assessment of historical and heritage buildings. Perhaps, you could suggest relevant and recent case studies.

    Many thanks,


  • Laura Lacreu asked a question in CD44:
    Does anyone know the molecular weight of CD44v5?

    The cells I am working with express CD44. I am trying to infer if the variant of CD44 they express is variant 5. The band I have seen has about 140 kDa. Thanks a lot.

  • 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

    Johan Frans Prins · Sage Wise 66 (Pty) Ltd


    "The problem with the epicyclical representation is that it represents the solution of the equations of motion-but doesn't allow any insight into the equations themselves and to the factors that can lead the same equations to display different solutions (parabolas and hyperbolas).

    Exactly the same as Minkowski's ridiculous space-time. It is just like epicycles not required to understand the actual physics of the Lorentz equations.

    The mathematical significance  of Lorentz transformations is completely different, since they map solutions of the equations of motion to other solutions of the equations of motion, while relying on particular properties of the equations themselves."

    I have nowhere EVER claimed that the Lorentz transformations are not consistent: I have only claimed that their interpretation is not consistent since it does not require Minkowski's mathematically and physically absurd construction of "space-time", just like the motion of the planets do not require epicycles to understand this motion.. 

    So please stop being such a totally dishonest person!

  • Aamir A. Hamza added an answer in Online Journalism:
    Procedure to put new online Journal?

    I am interested to start new online Journal on "International Journal on Farm Power Machinery & Energy in Agriculture". Experts are requested to suggest the procedure for online starting for it..(like steps...)

    Aamir A. Hamza · University of Bahri

    you have to have a domain and web site for your journal that was not used before. IT personnel through OJS will mange it.   site manager, journal manger, Editor-in-Cheif and expert dedicated reviewers, editors, proof readers,  should be assigned in advance.

  • Which is the best test to determine the minimum dimensions to keep after a Principal Component Analysis?

    In particular when there is no clear "elbow" in the scree plot and when to explain 70% of the variance in the data you need to keep more than 8 principal components.

    Daniel McNeish · University of Maryland, College Park

    The method that seems to be gaining traction in the literature is Horn's parallel analysis (HPA) . It is similar to Kaiser's rule where components with an eigenvalue greater than 1 are retained. However, instead of using 1 as cut-off with Kaiser's rule, HPA uses data simulated from random, uncorrelated variables (the same number of variables as the dataset of interest). If the eigenvalue for a component from the data exceeds the value from the HPA, then it should be retained. 

    There are several macros and software programs available that can be used to conduct a HPA. 

  • Eric B. J. Harris added an answer in Amines:
    Why some chemists prefer to perform N-formylation for the free amine before coupling reactions rather than reacting the free amine directly?

    Recently, I've seen in a patent a simple N-alkylation reaction of 2-aminobenzothiazole with ethyl bromoacetate. The inventors have carried out N-formylation reaction first followed by coupling with ethyl bromoacetate. So, I wonder why they did not react the free amino group directly with ethyl bromoacetate? Were they afraid of another side cyclization reaction? If so, what is the role of formyl group in this reaction and also to prevent this side reaction?

    Many thanks and sorry for that long question...!!!

    Eric B. J. Harris · Australian National University

    With the non formylated system you would get significant statistical problems in mono alkylation. In addition to the desired product, the bis alkylated product would also be observed as a significant byproduct. The formylated system can only be alkylated once, and results in a cleaner reaction overall.

  • How can I merge maps?

    I have 150 separate digital toposheets in dwg format. I need to merge these maps maps using contour layer only at once. Anyone can give me the idea, it will save my time.


    Ananta MS Pradhan · Pukyong National University

    @Bir Hassiba: I know that but I have 150 sheets so its time consuming. I need a python coding to do in a minute. Thank you

  • Talsha Bannick added an answer in International Law:
    Should we consider states as the only subjects of international law?

    In relation to the realist view, states are considered as the core or relevant actor in the international system.However due to changes happening in global politics, scholars and intellects are rethinking this concept. Therefore,should we still say that states are the only subject in international law...And why should we say they should or they should not.

    Talsha Bannick · Divine Word University

    Thank you both for your response.

  • Does anyone have experience with TiBase?

    TiBase - Sirona

  • R C K Chung added an answer in Herbarium:
    How can we make good herbarium specimens?

    We all know different methods are adopted for making herbarium for plants, fungi, algae, bryophytes etc. It is also known that flowers and fruits are usually crucial for identification. But what about bamboo? How do we make herbarium for bamboo species and what are the important parts to be preserved since flowering is rare event?

    R C K Chung · Forest Research Institute Malaysia (FRIM)

    Please refer to this published article and it helps: Soderstorm, T.R. & Young, S.M. 1983. A Guide to Collecting bamboos. Ann. Missouri Bot. Gard. 70: 128-136. An illustrated guide was presented in this article, showing which parts, especially vegetative, should be collected for a proper herbarium specimens. Instructions were also given on the preparation of preserved material in liquid and on the composition of the notes and label to accompany the collection.

  • Anando Sen added an answer in LaTeX:
    What is the best LaTeX editor for Mathematicians?

    I am looking for an easy-to-use free LaTeX editor that is friendly to Mathematicians who include many mathematical equations in their research articles. Any recommendations?

    Thank you!!

    Anando Sen · University of Houston

    kile for linux. texmaker for windows. texworks and texnic center are good too.

  • Can anyone recommend a small molecule inhibitor of tlr2? Ideally one that blocks tlr1/2 and tlr 2/6?

    I want to block tlr2 activation on human monocyte derived macrophages. I have tried a tlr2 antibody without much success. 

    Mikhail A Gavrilin · The Ohio State University

    CU CPT 22 from Tocris Bioscience is specific inhibitor of TLR2/1. We use it at 5 uM.

  • Shih-Wen Huang added an answer in Allergens:
    How can we compare a recombinant allergen with its native allergen?

    In peer-reviewed articles, mostly authors have mentioned that they have compared the IgE binding ability of a recombinant allergen to the native allergen with allergic patient sera. But I am interested to know how they can find the folding /aggregation pattern of a recombinant allergen. Or IgE binding test is enough to conclude that there were no considerable folding / aggregation occurs during the process. 

    Shih-Wen Huang · University of Florida

    That is a very intriguing question that I am afraid we have no good answer at this point. I have not seen a study describing in details how the stoichiometric changes of the IgE molecule occurred in binding on to natural allergens or recombinent allergens as yet.

    Regardless, even the results of IgE binding to a natural allergen or its recombinant allergen looks very close, at least for some allergens, especially foods or allergens to be included in allergy vaccine for immunotherapy (allergy shot) would be eventually tested in man. For instance, genetically altered food (say modified peanut) would be tested in vivo to see if allergic patients could tolerate it or not. Likewise, the effect of recombinant allergens for immunotherapy would be tested if patients symptoms would get better or not. In other words, no matter how IgE is bound to allergen, the final test would come after a real challenge in vivo is conducted..

  • Jiaqiang Liao added an answer in Marine Birds:
    Does anyone know if zero values need to be considered for data analysis of marine birds observations?

    I'm  working with observation data of giant petrels (Macronectes), and I'm not sure if I must consider zero values for abundance comparisons among sites

    Jiaqiang Liao · Sichuan University

    zero must be accounted! you can correct the bias by weighting or using mixed model.

    hurdle or zero inflated model can deal with excess zero !

  • Which forms of matter store static fields, e.g. gravitational?

    A body dropped from state of rest in the gravitational field of the Earth, begins to fall and its kinetic energy increases all the time. We say that the potential energy gets transformed into kinetic. But, assuming that there is vacuum around the body, where is stored this potential energy?

    Potential energy has a meaning only with respect to a system. In the system of a body+Earth the total energy of the system is conserved. The fall of the body is nothing more than a deformation of the system, and it would require the same energy to restore the system in its initial state. In a pure vacuum, without any field, there is no potential energy.

  • Huiming Zhang added an answer in FLUENT:
    How to improve the lateral and vertical velocity accuracy when simulating flow pattern in channel confluence?

    Dear all,

    I am using FLUENT (choose VOF model, Realizable k-epsilon model and Non-Equilibrium Wall Functions) to simulate the flow pattern in channel confluence with 90° confluence angle. But when I validat the velocity results, I find that only the velocity along the flow direction can match my laboratory experiment results, none of the lateral, vertical velocity and turbulent kinetic energy.

    Please help me and give me some advice, thank you very much.

    Huiming Zhang · Hohai University

    Thank you Mahdi for your advice. I will have a try.

  • Liang-Cheng Zhang added an answer in Microeconomics:
    What Interval to use for economies of scope: confidence interval or prediction interval?

    In economics, economic estimates are usually calculated by the combinations of predictions. Take economies of scope for instance. Once the cost function is estimated, economies of scope are estimated by the proportion of cost savings from joint production relative to fully integrated costs. The above costs are conditional expectations given that cost function coefficients equal to some fixed constants. Could anyone tell me that the interval for this estimate (economies of scope) is confidence interval or prediction interval?

    Liang-Cheng Zhang · Griffith University

    I currently estimate some inference measures about scope economies with a Bayesian approach. The question of the term for the interval annoys me when I read Professor Hyndman's blog. I believe Professor Picard gave the most precise answer. The answer to this question indeed depends. In fact, I asked Professor Hyndman the same question and he gave the short answer version of Professor Picard: 

    1. Confidence interval: compute either depending on whether you want to allow for uncertainty in the estimate only, or
    2. Prediction interval: whether you also want to allow for the observational uncertainty in future.

    However, I cannot understand the meaning until I read the above response from Professor Picard. Also thanks for all the contribution to this question!

  • Rao Gollapudi added an answer in MLR:
    Does anyone have an information about the ability of human B cells to proliferate into a well before MLR ?

    I would like to perform a MLR with human B cells as stimulators cells.

    Do I have to use mitomycine C before culture to avoid proliferation of B cells ?


  • Is there any good books or resources on Agent-Based Modeling?

    Is there any good books or resources on Agent-Based Modeling? 

    Alejandro Guerra-Hernández · University of Veracruz

    I like L. Sterling and K. Taveter. The Art of Agent-Oriented Modeling. The MIT Press, Cambridge, MA., London, England, 2009. 


  • Nechama Tatz asked a question in Packaging:
    How is psi used as a packaging signal in recombinant retroviruses?

    How is psi used as a packaging signal in recombinant retroviruses?

  • Jun-Feng Su added an answer in Microencapsulation:
    How can I prove the existence of a core material inside a microcapsule?

    I have attached an epoxy with a nanofiller material in presence of a solvent and have microencapsulated it. The shell material is Urea-Formaldehyde.Now I am facing difficulty to prove that the core materials have actually been encapsulated successfully. I have studied SEM,TEM, optical microscopy but nothing seems to confirm the core materials convincingly.

    Jun-Feng Su · Tianjin Polytechnic University

    You can cut the microcapsules and observe the cross-section morphology using SEM. Another method is using the FTIR through breaking the capsules.