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  • Is there a solid counter-argument against Dingle's old objection to Relativity Theory?
    Herbert Dingle's argument is as follows (1950):

    According to the theory, if you have two exactly similar clocks, A and B, and one is moving with respect to the other, they must work at different rates,i.e. one works more slowly than the other. But the theory also requires that you cannot distinguish which clock is the 'moving' one; it is equally true to say that A rests while B moves and that B rests while A moves. The question therefore arises: how does one determine, 3 consistently with the theory, which clock works the more slowly? Unless the question is answerable, the theory unavoidably requires that A works more slowly than B and B more slowly than A - which it requires no super- intelligence to see is impossible. Now, clearly, a theory that requires an impossibility cannot be true, and scientific integrity requires, therefore, either that the question just posed shall be answered, or else that the theory shall be acknowledged to be false.
    Stephen Crothers · Alpha Institute of Advanced Study

    F. Leyvraz:-  A vast array of experiments has revealed that energy and momentum is conserved in a closed system. The conservation of energy and momentum in a closed system has been raised by theoretical physics to a Law of Nature.  Any theory which violates this Law is in conflict with the experiments by which it was ascertained. General Relativity has a conservation law for Einstein's gravitational field and its material sources combined. There is no such thing as a conservation law in GR for matter alone (according to Einstein everything that is not his gravitational field is matter). Yet the only possible conservation law for energy and momentum in a closed system in GR is such that it does not satisfy the experiments that determined the usual conservation laws for a closed system. This is all explained in the following exposition:

    General Relativity: In Acknowledgement Of Professor Gerardus ‘t Hooft, Nobel Laureate, http://vixra.org/pdf/1409.0072v2.pdf

  • Miroslav Jicha added an answer in Fluid Mechanics:
    Why not take DNS results for validating turbulence models in fluid mechanics?

    According  to ASME standards validation of a physical/mathematical model has to be done by comparing model predictions with the "real world", i.e. with experimental results.

    Often, however, no such results are availible, at least not with  the necessary accuracy and error analysis when it comes to turbulent flow.

    Shouldn't we, as an alternative, take high quality DNS results instead and still call it "validation of a model" ?

    Miroslav Jicha · Brno University of Technology

    I agree that in many cases, DNS could/should be more accurate than experiments, the major problem is of course that DNS data for high Re number are not probably available.  But if I could vote on "validation of a model" I say yes, let´s use DNS. I know what I am talking about -  experiments, I mean reliable and accurate experiments, are often difficult to obtain, mainly in geometrically complicated structures. And yet, to ensure correct and well defined boundary conditions - the problem that DNS does not have.  So what to do? Make for example Ercoftac community to raise a discussion? That is true that in many cases DNS is being used as a validation tool. 

  • Lukas Kucera added an answer in MALDI-TOF:
    Does sinapinic acid purity affect MALDI sensitivity?
    We're trying to improve our sensitivity analysing proteins with our 5800 MALDI TOF/TOF. One thing that has come up is the purity of the sinapinic acid. Does it have an effect? We are buying it from Sigma and suspect we need to recrystallise it (as done for CHCA) but we are struggling to find a reliable method for doing so. If anyone can supply one or point me in the right direction it would be greatly appreciated.
    Lukas Kucera · Masaryk University

    I would also recommend that high quality test tube and pipette tip shall be used for sample preparation, Eppendorf works well. You can also use Eppendorf Protein LoBind tubes in order not to lose sample adsorbed onto the tube walls.

  • Yuri Rylov added an answer in Space Time:
    How does one define equality of two vectors in the space-time geometry of Minkowski?

    There are two versions of this definition (1) vectors AB and CD are equal, if their coordinates in inertial coordinate system are equal, (2) vectors AB and CD are equal, if scalar product (AB.CD} =|AB| |CD| and |AB|=|CD|. This definitions are equivalent for timelike vectors, but they are different for spacelike vectors. For instance, if AB1 =(r,r,0,z),  AB2 =(r,0,r,z),  CD=(0,0,0,z), then AB1=CD, AB2=CD, but AB1 is not equal to AB2.

    Yuri Rylov · Russian Academy of Sciences

    Dear Aleksei,
    You are right in the relation, that my definition of the scalar product differs from usual definition in terms of linear vector space. My definition of the equality of two vectors is intransitive in the geometry with arbitrary metric. But in the Euclidean it is transitive. Geometry with intransitive equality relation is nonaxiomatizable. Mathematicians consider that nonaxiomatizable geometries do not exist, because they know only one method of the geometry construction: deducing all geometric statements from axioms.
    I am physicist. I am investigating the space-time, and this position of mathematicians has no relation for me. It indifferent for me, whether or not the space-time geometry is axiomatizable, because I do not deduce geometrical statements and concepts from axioms. I use a more simple way of the geometry construction. I consider the proper Eucledean geometry GE and express all statements of GE in terms of Euclidean metric dE. It is always possible. To construct a geometry G, which is described by metric completely, I replace the Euclidean metric dE by the metric d of geometry G in all statements of Euclidean geometry GE. As a result I obtain all statements of geometry G expressed via metric d of geometry G. It is a very simple method of the geometry construction. In this construction one does not use proofs of theorems. All necessary theorems are proved in GE. If you have time, look my paper (it is a short paper about 5 pages) and write me your objections, if they will appear.  My paper:
    “ Metrical conception of the space-time geometry” Int. J. Theor, Phys.54, iss.1, 334-339, (2014), Electronic version on my site:


  • Ricardo Alvira added an answer in Complex Systems:
    How do you measure hierarchy within a complex system?

    For a given complex system, what measures, scales and/or method could you suggest to unveil a relational hierarchy among components?

    Ricardo Alvira · Universidad Politécnica de Madrid

    Dear Carlos

    I made a full check through Weaver's text [with adobe Acrobat 'find' function] and I can only find the term 'complex problems' but not the term 'complex system'

    Are you sure Weaver uses such term? 

    Kind Regards

  • Florian Knoop added an answer in Orbit:
    Can you provide details on the derivation of the ferromagnetic coupling proportional to J_2 of itinerant d_xz/d_xy orbitals to impurity d_xy orbitals?

    Dear Mr. Ruhman,

    I currently try to recapitulate your derivation of the spin-spin-interactions in appendix A to your paper. From the model explained up to that point, I see no way to reconstruct the ferromagnetic coupling constant J_2. Let me make this more explicit: The coupling of l=23 itinerant orbitals to the impurity l=1 orbital is described in the paper by the standard scalar product (leaving out the summation over impurity sites i)

    \sigma_l * S

    where \sigma_l is the spin operator for the conduction l-orbital and S is the spin operator for the impurity l=1 orbital.

    Following the usual second quantization of these operators which you also made explicit for S in the text, this contribution amounts to a term proportional to 

    \sigma_l * S = \sum_{s, s'} c+{l, s}c{l,s'}d+{1,s'}d{1,s}

    For l =23, we thus have different l indices for the conduction band c-operators than for the d operators.

    From your model, I expect no mixing between states of different l between conduction and impurity orbitals, for the reason that the Hamiltonian governing the exchange of c- and d-orbitals is of the form

    H = \sum_l tl c+ldl + h.c.,

    from which I do not see a way of producing spin-spin contributions other than with same l for c and d operators.

    Did I overlook something else or how did you achieve your result from the present model?

    Hopefully my exposition of the problem was clear enough and it would be appreciated a lot if you could comment on this issue.

    Best regards,

    Florian Knoop

    Florian Knoop · University of Leipzig

    Dear Jonathan,

    thanks for your reply. In the meantime I succeeded in rederiving the effective coupling constants in the singly occupied subspace from your impurity Hamiltonian. But thanks anyway for the further insights!

    I see your point concerning the mails from researchgate, maybe this question would have better been adressed directly via email, sorry. I'll think of it next time ;-).

    Best wishes,


  • Lisa Glickstein added an answer in Freezing:
    Can I extract the PBMCs from frozen blood samples?

    Dear all,

    I am planning to do a immune response study in pigs and I have a doubt that I hope someone can clarify me:

    I need to get blood from the pigs and then extract serum and PBMCs (Peripheral Blood Monocytes cells) from the blood. Does anyone know whether I can freeze the blood and make up the serum and extract the PBMCs after freezing the blood?

    If someone can clarify my doubt I'd be really grateful.

    Thanks in advance.


    Lisa Glickstein · Massachusetts General Hospital

    You must isolate the cells first and freeze them in freezing media (that contains a cryopreservant, generally DMSO). Freezing media works by partially dehydrating cells and secondly by minimizing the size of ice crystals that form. If you don't use it, the ice crystals essentially stab the cells to death from within. Also, proteins precipitate during freezing and altogether this would lead to a goopy mass of lysed RBC, precipitated proteins, and dead cell debris. Even if a few live cells remained, they would no longer be able to be separated on a density gradient. Even storing blood overnight at 4oC greatly diminishes the yield of viable cells.

  • Kenneth M Towe added an answer in Greenhouse Gases:
    Is CO2 increasing in all levels of troposphere? If yes, in which way the global warming is influenced by the different temperature of CO2 layers?

    In climate change/global warming studies, the Stefan Boltzmann
    formula is often used to estimate the amount of radiant energy which
    escapes outward into outer space from earth. The formula is derived
    under the assumption that the relevant emissivity of the emitter is a
    constant for all wave lengths, and its temperature exponent is 4. However,
    the earth’s greenhouse gases permit radiations to pass through
    the atmosphere freely only in some specific wave length windows. It is
    shown that the wave length dependence of emissivity can change the
    effective temperature exponent of the Stefan Boltzmann formula. (Source: Lam, H. S. (2007). On the Effective Stefan-Boltzmann Temperature Exponent of the Earth).

  • M.E. Stothers added an answer in Mental Rotation:
    What is the most efficient method for measurement of visuospatial thinking?

    One of my research areas is development and measurement of visuospatial thinking. I have some appropriate tests and tasks for it but this process takes place in human's brain. I am interested in suitable methods by which these processes would be traceable in the brain while the student solve a visuospatial stimulus (e.g. mental rotation). What kind of method is appropriate for it?

    Look at this site, which gives some examples for stimuli.


    M.E. Stothers · The University of Western Ontario

    Hi there,
    It depends on whether you need standardized, scaled scores; whether you are looking at one particular aspect of visuospatial ability (mental rotation only) or are interested in other processes that the Wechsler nonverbal subtests measure; whether you are interested in higher order perceptual reasoning, lower level perceptual organization, etc.. You might look at http://gestaltrevision.be/tests/index.php?language=en and 

    for examples of some of these differences, as well as work by Cornoldi and  Mammarella, who look at visual-spatial working memory -- e.g., spatial simultaneous versus spatial-sequential working memory, see Mammarella, I. C., Cornoldi, C., Pazzaglia, F., Toso, C., Grimoldi, M., & Vio, C., 2006, Brain and Cognition, 62, 58–67. doi:10.1016/j.bandc.2006.03.007. 

  • Luca Jaselli added an answer in Fossils:
    Model of Displaying card with specimen information?

    I am going to display fossils in the lab. I would be grateful if anyone send me the pattern of displaying tag containing the specimen information?

    Luca Jaselli · Museo di Storia Naturale "Antonio Stoppani", Venegono inf. (VA), Italy

    Dear Muhammad,

    attached an example for your consideration.



  • Alpana Thorat added an answer in Transition:
    There are two polymorphs how to correlate them monotropically/enantiotropically?

    I have a system which seems to have 2 polymorphs. Metastable polymorph transforms to another form through endothermic transition below melting points of both the forms during DSC heating. So according to transition rule polymorphs can be related to each other enantiotropically. However the heat of fusion reported for stable form is more than heat of fusion of metastable form, according to this rule it could be monotropic (difference in heat of fusion is only by 1kJ/mol). Is it possible that based on DSC results to conclude that the forms are enantiotropically related?

    Alpana Thorat · Indian Institute of Technology Gandhinagar

    Thank you very much Kaoru Aou for detailed explanation. It was helpful to understand the system. However, in one of the reports on Norfloxacin (http://pubs.acs.org/doi/abs/10.1021/cg060101u) authors have reported that if endothermic transformation is there in DSC and no reversible conversion upon cooling to metastable form observed then solely on the basis of absence of reversible conversions one can not say system is monotropic.This creates doubt in our mind. In our case we observe that at room temperature upto transition temperature both metastable and stable forms are stable, however above transition temperature only stable form is there. Would you like to further comment upon this. Thank you very much in advance. 

  • Gregg Pulley added an answer in Electric Vehicles:
    Can anyone recommend me data acquisition tools to collect velocity, voltage and current from actual driving cycle?

    Now I use Kayaba recorder. Any idea for collecting these data using other data acquisition for Electric Vehicle driving cycle? 

    Thank you

    Gregg Pulley · Meggit Sensing Systems, Colorado, USA

    You need to provide a lot more information before anyone can provide a reasonable answer to your question.  Are you measuring voltage and current?  What are the resolution and full-scale range requirements?   What sample rates do you need?   How many channels?  Can you mux the sampling, or does it have to be done simultaneously across two or more channels?  What kind of system do you intend to connect this to:  laptop with USB 2? PC Tower with PCIe?  Ethernet?   ISA?  HPIB?

  • Dudley J Benton added an answer in Mercury:
    Does anyone have a table of the thermodynamic properties of mercury up to the critical point (I need Ps, Vf, Vg, Hf, Hg, Sf, and Sg)?

    There are several documents online that have some of this information, but not all are up to the critical point. I'd like to have from the triple point up to the critical point. I have Psat but I at least need Vf and Vg. With Cp of the gas I could build the rest.

    Dudley J Benton · McHale Performance

    Thanks! That's exactly what I needed.

  • Zouheir Maalej asked a question in Dialectics:
    Diglossia and (non)-dysphemism?

    For RG colleagues working on diglossia, has anyone come across words or expressions across dialects that could be (i) inexistent in one dialect, (ii) existing but non-dysphemistic, (iii) existing and dysphemistic in another dialect?

  • Krzysztof Treder added an answer in Immunosensor:
    Immunosesnor vs ELISA. Can any one let me know distinguish advantages of immunosensor over ELISA?

    I have read a lot of articles and review articles regarding immunosensor, in the articles researcher compares the sensitivity of immunosensor vs ELISA. But other than this, I could not any distinguish advantage of immunosesnor over ELISA? Could anyone let me know the advantages of immunosensor over ELISA?

    Krzysztof Treder · Instytut Hodowli i Aklimatyzacji Roslin

    Hi Om, I think its the speed, what can be the advantage of immunosensors over ELISA. With immunosensors you can detect target antigen in minutes while by ELISA you will get your results in hours.

  • Nicholas Almond added an answer in Cognition:
    How useful is experimental research under laboratory conditions in understanding the nature of human cognition?

    Need some helps with answering this question regarding Human Cognition. Thanks in advance!

    Nicholas Almond · University of Leeds

    @ Annette Milnik 

    You have a very good point, but if you conduct questionnaire studies before conducting experimental techniques then you have a better idea of what cognitive abilities can be measured and what variables need controlling for. You cannot just conduct observational studies and introspection without conducting empirical research first.

    Laboratory studies help us to devise techniques which can be used in real life situations to help people with certain cognitive impairments. You can't just ignore all the experimental data and use introspection or observational studies to understand human cognition... Come back Freud all is forgiven ;)

  • Jochen Wilhelm added an answer in Cycling:
    What is the easiest way to normalize data set to time?

    I would really like to know how to normalize simple and easy the data set to the time. We have conducted cycling test of 30 minutes but some subject couldn't succeeded to finish all 30 minutes of cycling. How can I normalize the data set to the time in a situation where I have some subjects that have been cycling only 12, 17 or 20 minutes but most of them have succeeded to finish all 30 minutes of cycling on ergometer. Thank you

    Jochen Wilhelm · Justus-Liebig-Universität Gießen

    Have you made several measurments during the time of cycling, or did you just measure before and after cycling (whenever the person finished cycling)?

    In the former case you can use a mixed model approach to model the time-dependency of the response and it does not matter if some persons stopped earlier or later.

    In the latter case you have no information about the time-course. One may rely on assumptions here but this is typically not a very good idea. However, wiithout having this information there is no way "normalize" your data to time. I'd suggest to analyze only the data from the people who really cycled 30min and "forget" the rest. But this requires an extensive discussion of the results because the people likely stopped earlier because they were reaching their limit, and this is likely be associated with the response (just a guess, though, but this is very typically the case). So you have "missing data", and this data is not "missing at random". So the fact that this data is missing will bias the results from the available data. The possible direction and extent and relevance of this bias must be carefully discussed, and this can be a difficult task.

  • Aroon Shenoy added an answer in Shear Stress:
    Working mode in a Rhéometer?

    What is the difference between working with a shear stress imposed or working with a shear rate imposed on a rheometer?i need a physical explacation pleaz.

    Aroon Shenoy · SAICO

    Whether a controlled stress or a controlled strain experiment is performed, the resulting rheological parameter theoretically should have the same value even if the material being tested is non-Newtonian provided, of course, the evaluation is done at identical values of stress and strain at an identical temperature and an identical pre-shear and measuring shear deformation history.  So in that sense, it should not matter whether a controlled stress experiment or a strain experiment is done to obtain the rheological characteristics of the material.  However, the caveat is that it is difficult to have identical shear deformation histories in the controlled stress experiment and in the controlled strain experiment.  Hence, one would land up with different rheological characteristics of the material even when compared at identical temperatures.

    Controlled strain experiment is normally the preferred one and rightly so, because it is easier to visualize and calculate the actual deformation (strain or strain rate) that the material is undergoing in any realistic practical situation.  On the other hand, constant stress experiments can result in deformations that are unrealistic to any practical situation and would not represent the true material behavior simply because the material does not see those kinds of deformations in reality.  Many researchers fall a prey to this sort of meaningless experimentation and obtain values indiscreetly outside the range of significance just because the equipment is capable of producing the information.  There are researchers who perform multi-stress experiments under controlled stress conditions wherein the response to the high levels of imposed stress create very unrealistic deformations that are well beyond any level of deformation that the material sees in practice.

    It is important that whether a controlled stress or a controlled strain experiment is done, the range of imposed stress or strain as well as the range of the response strain or stress must be within the appropriate levels that the material sees in actual practice in an engineering application.  Some ideas about the importance and relevance of getting rheological data within the appropriate applicability and correct sensitivity ranges can be obtained through the fundamentals discussed in the following books:

    1. Aroon V. Shenoy, Rheology of Filled Polymer Systems, Kluwer Academic Publishers, Netherlands (1999).

    2. Charles P. MacDermott and Aroon V. Shenoy, Selecting Thermoplastics for Engineering Applications, Marcel Dekker Inc., New York (1997).

    3. A. V. Shenoy and D. R. Saini, Thermoplastic Melt Rheology and Processing, Marcel Dekker Inc., New York (1996).

  • Barbara Hank added an answer in Quality of Teaching:
    Does anyone have experience with, or know any references to, alternative ways of assessing the quality of teaching and learning in higher education?

    I'm particularly interested in experience with using qualitative methods like focus groups and interviews as a way of getting deeper information from students and/or lecturers about the quality of teaching and learning than using traditional surveys.

  • Panayot Tanchev added an answer in Necrosis:
    Are bisphosphonate able to prevent surgical interference in early avascular necrosis?

    Patient with hip pain and normal x-ray  but MRI  shows early avascular necrosis of femural head.

    Panayot Tanchev · Medical University of Sofia

    Thank you, Dr. Pruijs, for this discussion.

  • Domenico Rossignoli added an answer in Germany:
    Are there systematic differences concerning the SOC between people born in Eastern Germany and Western Germany?

    Hello. I am looking for data concerning subgroup analysis of people born in Western Germany (the former Federal Republic of Germany) and Eastern Germany (the former German Democratic Republic) with special respect to the sense of cohearance.

    Domenico Rossignoli · Catholic University of the Sacred Heart

    Hi, I am not sure if this can help, but I recently came across a study on the difference in social and personal attitudes between Eastern and Western Germans. The study, by Ariely et al. (2014),  is in the field of behavioral economics, and shows the results of a mind-cheating experiment. See the attached file for the full paper.

  • Rik van Dinteren added an answer in Neurobiology:
    Will an understanding of the neural substrates of mental disorders revolutionize diagnostics and treatment?

    Dear all,

    There is an expectation that understanding the neural substrates of mental disorders will revolutionize the field of psychiatry, in terms of improving diagnostics and treatment. However, the clinical value of neurobiological research into mental disorders has so far been minimal.

    What are your opinion on this matter?
    Do you agree that an understanding of the biology of psychiatric disorders (genetics, molecular, brain circuits etc) will lead to improved diagnostics and treatment, or are the expectations of a ”revolution” exaggerated?

    I’m interested in hearing your opinions on this matter.

    Rik van Dinteren · Radboud University Nijmegen

    I think it will. However, not so much for diagnostics. Current diagnoses of mental disorders are based on behavioral observations. Probably a group of, say, MDD patients have varying underlying disorders in neural substrates. So the aim should not be to improve diagnostics (how could you improve this when a diagnosis is based on behavior?), but more in prognostics, that is treatment outcome. This doesn't necessarily has to be related to a diagnosis.

  • Scott Lett added an answer in Standard Error:
    What is the difference between asymptotic standard error and standard error?

    I know about standard error, but not getting idea about the asymptotic standard error and how it is related to standard error.

    Emmanuel, you are correct, your formula is correct by the definition of the standard error of the mean.   

  • Xiaoquan Sun added an answer in NAMD:
    Have you experienced a problem with water H-O-H angles in namd simulation?

    When I perform minimization using namd for proteins solvated in water I notice that the water angles are drastically deviated from 104.5. Have you ever had this problem? How did you fix it? For more information, here are the steps I take:

    1. I use amber to build the topology and crd files. 

    2. The water model is TIP3P

    3. The generated pdb files by tLeap (Amber) are perfectly fine with regards to the water angles as well as the bond lengths; They all obey the TIP3P model. 

    4. After the minimization, the average angle of water molecules is around 99 degrees. 

    5. If I use SHAKE or SETLLE algorithms, the water bonds remain rigid however, the water angles still deviates drastically from 104.5. 

    6. As I read somewhere, one possibility is that the new versions of AMBER do not record the water angle in the topology file and consequently it is not read by namd. But a colleague of mine is performing DNA simulations using CHARMM (instead of amber) force field in namd and he has the same problem with water angles. 

    Please let me know if I need to provide any further information.

    I appreciate your comments. 

    Xiaoquan Sun · University of Arkansas

    I am using AMBER11 to run a TIP3P water box. I remembered the TIP3P water is treated as a triangle in AMBER. You can find the bond information for HW-HW in GAFF or AMBER99 Force Field ($AMBERHOME/dat/leap/parm). A tutorial said this would save computing time. I think NAMD may be ignored the part of force field parameter and has such a problem.

  • Is mixed lymphocyte reaction(MLR)or ELISPOT more sensitive to T cell activation?

    MLR and ELISPOT----- mix the T cells with the  stimulator(cells),which one is more sensitive to the stimulator? 

    Lisa Glickstein · Massachusetts General Hospital

    ELISPOT is measuring an early response, and is generally the most sensitive. MLR are measuring a more complex response to stimulation, but can also be very sensitive. It is possible that you will measure different types of cells with these two assays (terminally differentiated cells that produce cytokine might not proliferate, but rather die). If the response is so low, or you do not see it with both tests, you need to confirm with some other tests (cell death, surface markers) to be sure you fully understand the response you are measuring. We used human (but not autologous) serum for human tests and FBS for mouse tests. I would not do serum-free, first because it stresses the cells and second because serum contains proteins that bind to cell surface proteins and the plastic non-specifically and this coating seems to reduce non-specific responses due to spurious cell-cell interactions or "excess" adherence. If you are concerned about your particular situation (it might be sensitive to serum proteins) then you can try a serum substitute or modified serum. Again, when working with extremely low level responses, care needs to be taken to be certain that you are not measuring an artifact.

  • Steven Craighead added an answer in Mathematics:
    Does anyone know the status of this old unsolved problem from the American Math Monthly?

    Let S be a non-empty set of primes, such that whenever s,t are in S, so are all the prime factors of st+1. Is S the set of all primes?

    Steven Craighead · Columbia University

    I think the problem is well stated.

  • What Biochemical microbial pathways could be involved in conversion of derived pharmaceuticals in the original parent compounds in wastewater?

    On the basis of literature we are sure that wastewater microbial community have the ability to retransform metabolized pharmaceuticals in the original parent compound, for isntance the deacetylation or deglucuronization of antibiotics found in wastewater, excreted by human body.

    Does anyone have a clue about the pathway? Do you think the reaction is unspecific and that´s could be the meaning of a trend of degradation with a high Kbio ?

  • Nicolás Valera added an answer in Diquat:
    Can anyone help me to extract paraquat/diquat from potato?

    I am using the published method to extract paraquat/diquat from potato. I used 10 g sample shake with 1:1 MeOH:0.1 N HCl for 10 min and heat in a water bath at 80 C for 15 min and shake more for 10 min. I determined the analytes by LC/MS. Diquat is good with recovery around 100%, but I got low recovery for paraquat (around 40%) constantly. I use matrix matched standard and with internal standard.

    Nicolás Valera · State Research Center for Experimental Agroindustrial Production

    Did you try a Solid Phase Extraction? 

  • You might also be interested in this paper

    Arquit Niederberger, A. (2014). Low-Carbon China: Innovation beyond Efficiency (published in Mandarin), Plant Engineering Consultants 2014(2): 31-35. [English version]

    This paper posits that business model innovation is required to achieve truly low-carbon economies, and provides several industry examples, including the fertilizer industry.

    You can download via the link below.


  • Zouheir Maalej asked a question in Corruption:
    Correlation between corruption and democratization?

    Is there literature out there about the state/degree of corruption and the process of democratization? Any pointers will be most welcome.