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  • Chunde Yao added an answer in Gasoline:
    Which has higher calorific value gasoline or CNG ?

    i'm confusing with the energy content of both, with mass energy content the CNG has higher specific energy (MJ/Kg), but with volume energy content the gasoline has higher specific energy (MJ/L) 

    Chunde Yao · Tianjin University

    The calorific value of CNG is higher than that of gasoline, the former one is 50 MJ/kg, the later one just 42.5 MJ/kg acorrding to Automotive handbook 3rd edition.

  • Rajinder Kumar added an answer in Grain Boundaries:
    How can I analyze grain and grain boundary resistance from impedance data?

    many peoples are plotting cole -cole between z' and z'' and many others between M' and M'',,,,then the what is basic behind this? please can anybody help me in detail.

    Rajinder Kumar · Institute of Nano Science and Technology

    The Z0 vs.Z00 curve is composed of two semicircles, a small semi-
    circle at high frequencies indicates the effect of grain and
    large semicircle at low frequencies indicates the grain
    boundary effect. The intercept of the semicircle on the
    real axis gives the resistance of grain (Rb) and grain boundary (Rgb) of the corresponding component con-tributing towards the impedance of the sample. The ca-
    pacitance (C) of each component can be calculated using
    the formula omeg*time(tou) = 2 pi*fmax*RC= 1,

    fmax is the frequency of the maximum of the semicircle, omega=2pi*f max and tou is
    the relaxation time.

  • Vladimir A. Kulchitsky added an answer in Asd:
    Can anyone recommend an observational coding system for repetitive behaviors associated with ASD?

    I am looking for an observations system for RRBs and SIBs that I could use in a classroom setting.

    Vladimir A. Kulchitsky · National Academy of Sciences of Belarus

    Maybe some scientific articles will help you to find the right path. Please, rate the app.

  • Do you have data or experience with peritoneal cavity conditioning ?

    Peritoneal cavity conditioning affects postoperative pain, fatigue and adhesions

    Lone Hummelshoj · World Endometriosis Research Foundation (WERF)

    Not 100% sure what you mean? Perhaps we can discuss in Lisboa?

  • Who rewrote General Relativity?

    Einstein's General Theory of Relativity seems to have “crashed” as a scientific theory in about ~1960, and to have been "rebooted" some time in the early 1960s as "modern GR" with a different set of definitions and rules that differ from those laid out by Einstein.

    I'd like to know who originally made those "redesign" decisions, how the community consensus was reached, and where the changes (and their justifications) are documented.

    Background: Einstein had based his theory on the General Principle of Relativity: the idea that all motion was relative, and that even “absolute” motions such as rotations and accelerations could successfully be “relativised” if bodies showing those relative motions could be associated with suitable gravitational/distortional effects. This was an idea previously proposed by Ernst Mach, and Einstein described his general theory as being the theoretical embodiment of Mach's principle.

    For derivational convenience, Einstein also initially assumed that the theory should reduce to the physics of special relativity over small regions.

    However, the publication of the Harwell group's 1960 paper on centrifuge redshifts (Phys. Rev. Lett. 4, 165 (1960) ) apparently triggered a controversy within the community, and an appreciation that a literal application of the GPoR seemed to lead to results that were geometrically incompatible with special relativity – the consequence of the GPoR being treated as a “law” then seemed to be not only the loss of Einstein's 1905 "Special" theory, but also the loss of the 1916 "General" theory that had been partly built upon it (Schild, Am. J. Phys. 28, 778 (1960) ).

    We were facing the unpalatable prospect of a major rewrite of theoretical physics, and although a rederivation of GR to avoid its dependency on SR had already been suggested by Einstein back in 1950 (SciAm 182, 4, 13-17), we found it easier to modify the rules of general relativity to allow the GPoR to be suspended in cases where it seemed to clash with other parts of the 1916 theory. In effect, we accepted that the original “SR+GPoR” structure was logically inconsistent, but maintained order by redefining SR's position in GR's definitional hierarchy to one in which GR could not disagree with SR “by definition”, and establishing a "failure etiquette" ("If the GPoR conflicts with SR, keep SR and suspend the GPoR").

    This change seems to have happened with minimal recorded public comment or discussion. Although Schild's paper mentions discussions and "a certain lack of unanimity" in the community as to how to proceed (before he presents the "modern GR" position as unavoidable) Schild doesn't indicate who participated in those discussions.

    I'd like to know who was on the committee, who voted for or against the change, and whether any of those concerned published anything on the nature of the 1960 crisis and the chosen response. Does anyone here remember it or have direct personal experience of what happened? Is there any historical record of the episode other than the rather skimpy Schild paper? Did anyone else publish the arguments for modifying Einstein's theory, or the contemporary arguments why GR1916 couldn't continue to be used in its pre-1960 form?

    Any references to additional contemporary material would be very, very welcome.

    Stefano Quattrini · Sapienza University of Rome

    Dear Eric,

    "There will be a spherically symmetrical energy momentum tensor and consequently a curvature of space inside the mass"

    Sure as also Prof. Daniel Baldomir affirmed.

    The energy momentum stress tensor is a function of the energies and momenta content  in the volume so  it is also a  function of the density of mass. In the earth's core such density is remarkable compared to the earth's crust or more than double the average density of the planet.

  • Arturo Tozzi added an answer in Fractals:
    Transcranial stimulation: is the role of fractals in the waveforms underestimated?

    We suggest that the techniques of transcranial electrical stimulation need to be keept into account, along with the amplitude and frequency of the applied waveforms (Reato), and also their scaling slope.  

    Arturo Tozzi · Azienda Sanitaria Locale Napoli 2 Nord

    The role of my "fractal" external currents is no to give a message to the cortex, rather to activate, modulate and entrain the message already contained in each cortical area.  The change in fractal slope in currents, according to my idea, could activate the cortex in a different way, so that the sensation (or each other function o the brain) becomes different when the power-law of the external input is modified.  

    I too think that the spikes, other than containing the message, synchronize  and fasten the brain activity, but it is a matter of dispute...  

  • Maximilian Weber asked a question in Protocols:
    Spheroid Sprouting Assay Protocol?


    I am looking for a spheroid sprouting assay protocol.

    Best Regards

  • Measuring customer satisfaction: what is the best control variable or approximation for customer satisfaction?

    Can one measure customer satisfaction with several scales. So far so good. Then you can measure several dependent variables, e.g. word of mouth, loyalty, repurchase behavior etc.

    Since one probably cannot measure the real customer satisfaction to 100% I would like to know which variable or construct or behavior (as a dependent variable following customer satisfaction) has a very plausible connection (or the closest/strongest link) to customer satisfaction so that I can compare this with the results for customer satisfaction. Thank your for your answers and inputs!

    Manfred Hammerl · Karl-Franzens-Universität Graz

    dear researchers, thank you all for your answers so far! i think there are some really valuable hints and suggestions in the answers.

    i will now check your suggestions in details and study the literature some of you suggested.

  • Can anyone give me a reference to field measures of Total Alkalinity in estuarine areas with values exceeding 2580 µmol/kg?

    TA values higher than 2580 µmol/kg are not frequent in estuaries. I have in situ data with such values and need to compare it with similar occurrences.

    Marcos Mateus · Technical University of Lisbon

    Thank you Natacha and Bernardo. The work is now complete:


  • Milad Malekzadeh added an answer in Soil Salinity:
    Which is the best algorithm used to calculate the Soil salinity by using Remote sensing data ?

    I want to know which the best algorithm used to estimate or calculate the soil salinity especially when I have used the visible band and NIR-MIR . 

    Milad Malekzadeh · University of Tehran

    Dear faez,

    I think it might be helpful if you compare result of NDVI index from two group of training data (soil with low salinity rate and soil with high salinity rate) and then the differences between two group can help you to detect the salinity rate of soil.
    best regards.

  • Maurizio Buggio asked a question in siRNA:
    How can I quantify the siRNA released in the cytoplasm?

    I'm doing silencing in cancer cells with siRNA. I'd like to quantify the siRNA that is present and free in the cytoplasm. What is a good protocol?

  • Naïma Amrani added an answer in Nuclear Reactions:
    How is the (n,p) reaction cross section calculated in statistical models?

    Theoretical development 

    Naïma Amrani · Ferhat Abbas University of Setif

    Hi Mahmoud

    Using feshbach-weisskopf model 

  • Electroporation of Pichia pastoris - what parameters do you use?

    I'm about to transform Pichia pastoris with pPICZ alpha and pGAPZalpha with my GOI and because the Invitrogen manual doesn't specify the conditions, I'd like to ask you, what voltage do you use?

    Further, while searching the answer online, I found this paper (attached). I just started reading it, but Table 2 caught my attention. They report highest efficiency (transpormants per ug of DNA) with 10 ng of DNA. As the manual say to use 5-10 ug of DNA, that seems awfully low amount. So how much DNA do you use?

    Kristof De Schutter · Ghent University

    That is indeed the difference, although one can use 1 µg of DNA with the invitrogen protocol (not needed to have the 5-10µg) but with the pre-treatment the amount of DNA can indeed be lowered to 10 ng

    just note that transformation with 10 ng DNA is most efficient (most CFU/ µg DNA), but more DNA can be added to obtain more CFU per transformation

  • Christopher R. Lee added an answer in BSTFA:
    What's the best wash solvent for cleaning the syringe used to inject BSTFA+TMCS in a GC-MS?

    I need the help because I break 6 syringes in one month. I use hexane, ethyl acetate and ethanol for cleaning, but they don't resolve my problem. The plunger of the syringe gets stuck when I analyze many samples.

    Christopher R. Lee · Retired

    It's a little bit off-topic, but Satoshi's answer provides, indirectly, a reminder that ordinary soft tissues are a disaster in all kinds of laboratories. Kimwipes have been around for a long time, and as there seems to be no satisfactory alternative I regret not having shares in their manufacturer; institutional procurement services sometimes need persuading that the choice of such apparantly trivial items can be critical.

  • Tyll Krüger added an answer in Differentiation:
    Are there known example of third order phase transitions ?

    A  phase transition of order k is mathematically characterized by a loss of regularity of free energy f: f is k-1 differentiable but not k differentiable. There are many examples of first and second order phase transitions in experiments and in models. There are also cases where f is C^{\infty} but not analytic (Griffith singularities).

    But are their known example of phase transition of order k, k>2 ?

    A third order phase transition would mean that quantities like susceptibility or heat capacity are not differentiable with respect to parameters variations. But I have no idea of what this means physically.

    Tyll Krüger · Wroclaw University of Technology

    Dear Bruno,

    you might have  a look in the paper by Bollobas, Janson and Riordan :"THE PHASE TRANSITION IN INHOMOGENEOUS RANDOM GRAPHS" especially pages 117-121. They construct random graph models where the giant component has phase transitions of arbitrary exponents larger equal one. Of course It is only weakly related to physical systems in statistical mechanics.

    Hope you and the family are well. I'm meanwhile permanently at the Technical University in Wroclaw. In May or June I will visit Serge in Marseille. Maybe we can arrange for a meeting. Would be happy to see you. We could also think of some French Polish travel grants applications. What are your prime topics of interest right now.

    My official mail is tyll.krueger@pwr.wroc.pl

    or tyll.krueger@googlemail.com

    Many greetings


  • Awatef Balobaid added an answer in Cloud:
    Which is the best tool to simulate the cloud?

    What is the most popular tools for simulation cloud? and what is the best one if I want to simulate in cluster, private cloud and public cloud environment??


    Awatef Balobaid · Bowling Green State University

    Thanks a lot.

  • Sick Building syndrome causes financial losses and absenteeism, what could be the impact on the workers in the manufacturing and mining industries?

    Compared to office workers, manufacturing and primary industry workers seem to be exposed to more serious health threats, could SBS be more of a serious issue, Why or why not?

    Joel Nyoni · Deakin University

    I will add the threats of cancers from effects of SBS (from poor indoor air quality), both factory and office workers are reportedly affected by this.

  • Azzam K Almosallami 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.

    Dear Yuri Rylov,

    According to my paper " The Quantization of General Relativity: Photon Mediates Gravitation" http://dx.doi.org/10.14299/ijser.2014.10.002 I found there is no space-time continuum, it is only time! Reinterpretation of Lorentz transformation according to Copenhagen school will lead the Lorentz transformation is vacuum energy dependent and not depend on the relative velocity. Do you know why the discreteness and discontinuity, indeterminism, uncausality which existed in quantum can't be interpreted according to relativity, because of the concept of Einstein of the space-time continuum which is adopted in his interpretation to the Lorentz transformation. Because of the space-time continuum, it is resulted determinism, causality and continuity in SRT. Because of that Einstein could not interpret the Spooky action and quantum entanglement according to his space-time continuum in SRT.  The discreteness, indeterminism, and the uncausality  exist in quantum depend on observation only but not locally. Because of that the speed of light is locally constant and equals to c speed of light in vacuum. According to my transformation it is possible measuring faster than light without violation of Lorentz transformation or causality, but that depends on observation but not locally. Because of that quantum theory built basis on observation and experiment. My transformation will lead to the Heisenberg uncertainty principle, and the wave-particle duality, which they are one thing.

  • How do I interpret the results of interaction effects between two categorical variables?

    I will appreciate it very much if someone can help me with the following problem. I am testing whether the effect of my key independent variable (mother's weekly work hours in 3 categories - 0, 1 and 2) is different for each developmental stage of the child (3 categories - 1- early childhood, 2- middle childhood and 3- adolescence). This is a panel design (fixed-effects) but this should make no difference. 

    In stata I use the following command:  xtreg dep_var devstage##moth_work, fe

    Before that I set the reference category for mother's work hours to be the middle category (which is 1 in my case). In case I don't specify a reference category stata just picks the first one but it drops it in the main as well as in the interaction effects "because of multicolinearity". 

    You can see the results in the attached file. The interpretation of the main effects I think is clear but not the interaction effects. What is my reference category for the interaction effects in my case? Why there are so many combinations missing (there are only 4 coefficients while 3x3 =9? How can I interpret the coefficients of the interaction terms which are in the apposite direction compared to the main effect of the key explanatory variable? Or maybe I do something wrong?

    Thank you for your help! 

    Francisco Olivos · Pontifical Catholic University of Chile

    "Addressing devstage, held in isolation:

    devstage==2, estimated Y significantly decreases by -7.187

    devstage==3, estimated Y significant decreases by -19.319

    Conclusion, as devstage increases, the estimated value of Y decreases"

    The main effect of devstage in this case is more complex, because is the value when moth_work==1. 

  • Andrew Hook added an answer in Plasma:
    How can I have a good adhesion between metal and polymer ?

    Is it possible to provide a strong bonding between metal and polymer interface via plasma process ? What are the possible conditions to have this ?

    Andrew Hook · University of Nottingham

    What metal are you working with and what sort of forces does the coating need to withstand?

  • Hemza Kheribot added an answer in JCPDS:
    Can anyone provide me JCPDS XRD files for Ag and Au Nanoparticles? ?

    I need JCPDS file for Ag and Au Nanoparticles (NPs were synthesized using biomaterials).Literature says that for Ag NPs, JCPDS file no. is JCPDS file no. 04-0783, while for Au NPs it is 01-1174.

    Is it OK if there is minor variation in the angles compared to the JCPDS file? 

  • Leonardo Ensslin added an answer in Raw Materials:
    Can anyone list the factors that are responsible for material shortage in manufacturing industry?

    While manufacturing it may be possible that productivity may get affected due to shortage of raw material, I am interested in finding real life factors that are affecting productivity of manufacturing firm.

    Leonardo Ensslin · Federal University of Santa Catarina

    I cannot tell you  a magical set of KPI for your problem. Each context including in it the manager will have a different set of KPI. From what I can do is recommending a process that helps in determining the KPI to your specific context. The process is the MCDA-C; Multicriteria Decision Aid - Constructivist. It realy Works.

  • A. A. Zisman added an answer in Extrusion:
    How i can examine that how much of deformation has been carried out under compression during backward extrusion process?

    Some materials show different behavior when subjected to compressional loads instead of tensional loads. when we want to study these materials in the backward extrusion process, we usually suppose that due to this fact that a large portion of deformation is carried out under compression, so only the data from compression test is applicable for further analyses. but every one knows that this assumption imposes errors to the results. how i can compute that how much of deformation has been carried out under tension or compression during the process of backward extrusion? (to compute the error percent of my results due to neglecting this behavior)

    A. A. Zisman · St. Petersburg State Polytechnical University

    The best way is to apply EBSD(SEM) orientation imaging with use of a special option to

    map a degree of crystal curvature, roughly proportional to dislocation density (work hardening for whatever deformations scheme).In most of up to date facilities of the kind it is the so called KAM (kernel average misorientation) .  Employ, say, a scanning step of 0.1 micron and n for KAM (number of coordination shells) of 3. Then  you will be able:

    -to get an average plastic distortion characteristic after your treatment;

    -to compare that with results of standard tensile deformation (of various degree) using relevant "reference" samples. 

    The only limitation is that intermediate recovery or recrystallization must be avoided.

  • Silvia Diana Matteucci added an answer in Landscape:
    Why categorical maps are used in landscape fragmentation analysis?

    Why most of landscape fragmentation studies use use categorical maps to depict patterns of fragmentation rathern than conventional topographical maps?

    Silvia Diana Matteucci · National Scientific and Technical Research Council

    As I mentioned 12 days ago, vegetation cover maps are also analyzed with metrics developed for understanding continuous landcover maps. Topography changes continuously (unless a barrier such as a terrace or a river cuts the landscape) and this metrics could be used to understand associations between topography and other operating factors, and not necessarily changes in time.

  • Paul Dickinson added an answer in Pathway Analysis:
    Could anyone recommend a software for pathway analysis of microarray data (preferably freeware)?

    Hallo everybody!

    We performed gene expression analysis (Affymetrix Prime View Arrays) to compare two conditions. We have got about 3000 differentially expressed genes. Even if we filter only the highly significant results, we still have such a bulk of data that makes it impossible to find out a pathway or mechanism to explain the differences between the two conditions.

    Is there a good freeware software to do that? Did anyone use an IPA trial? Is the trial version of the software fully functional or are there restrictions to the bulk of data that one can submit?

    Thank you very much for your answers! 


    Paul Dickinson · The University of Edinburgh

    If you want to try a free "IPA-like" software tool I'd recommend STRING ( http://www.string-db.org ) to generate interaction networks but with a differential list of several thousand genes you will need to break this down to generate meaningful networks. You could try BioLayout Express3D ( http://www.biolayout.org ) for a free tool that uses Pearson correlation and Markov clustering to produce clusters of coexpression - this works very well on multi-thread/processor systems like a MacPro.

  • Shuhao Qin added an answer in PVDF Membrane:
    How to make a hot stretched polymer film sample brittle enough by cryofracture in liquid nitrogen?

    I have a hot stretched PVDF film sample which I want to do cryofracture. But It is very flexible even after long time (40 min) soaking in liquid nitrogen. In fact, pouring in liquid nitrogen didn't change its flexibility. Does anyone have an idea how I can make my sample brittle enough to fracture easily and make it a good SEM sample?

    Shuhao Qin · Guizhou University

    maybe you can try embedding the pvdf film by  using epoxy resin。

  • isolation and purification of 6-gingeol
    Hi every body, I am very happy to join this group.
    I ask if any one know a simple method for isolation and purification of 6-gingerol using normal phase chromatography
    Shaban Ahmed Ali Abdel-Raheem · Assiut University

    Dear friend

    You can see the attached papers . I hope to help you

  • Abolfazl Barzegar added an answer in Ligand:
    How can we fix just one dimension of center of mass of one molecule in Gromacs ?

    I have a box of one ligand and water in GROMACS,I would like to fix the motion of ligand just in z direction (center of mass of ligand not all its atoms),as I know freezgrps freeze atoms in x,y or z direction,how can we use for center of mass of molecule? 

    Abolfazl Barzegar · University of Tabriz

    Add one of following comments into the mdp file:




  • Nina Duque asked a question in Fashion:
    Looking for critical reviews of Danah Boyd's new book, "It's complicated"?

    I'm working on a review of her new book chapter by chapter for a class. I've found many articles "reviewing" her book, but after close inspection most if not all tend to be rave reviews rather then posed reflections and study on and of her ideas. I need to find source material that examines in a critical fashion the ideas she puts forth. Thanks!