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  • Sara Farahani added an answer in GaussView:
    Does anyone here know how to generate Frank-Condon spectrum in GaussView?

    I use the 3 step approach and the error happens in the third one.The frequencies and checkpoints for the initial and final states are well generated but an error happens in the third step. 

    Sometimes generating the Frank-Condon spectrum starts and after a few lines the error happens and in most of the cases it does dot even start.

    I wonder if it happens because of a problem in entering the commands or there's a problem with checkpoints. A command sample that has properly worked is appreciated.

    Thank you in advance for your help and suggestions.


    Sara Farahani · The University of Waikato

    Hello everyone and thank you so much for your help.

    I tried to use a simpler molecule to work with and right now and using the suggestions I received, I'm running the jobs. I 'll be back with result.

    Thank you


  • Hamed Sharghi asked a question in Solitons:
    What is the meaning of the kink?

    I think it is similar to soliton

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    I'd like to know who originally made those "redesign" decisions, how the community consensus was reached, and where the changes (and their justifications) are documented.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

  • What is the correct assumption in using EBB, TB or HOBT?Plane stress or plane strain condition?

    When we use different beam theories such as Euler-Bernoulli, Timoshenko or higher order beam models for a rectangular cross section beam with L/h=8 and b=h, is it true to assume the plane stress condition?

    Mohammad Abdollahian · University of Kashan

    Therefore, for a beam with the mentioned dimensions the plane stress assumption is true or not?

  • Daniel Baldomir added an answer in Quantum Physics:
    Is the state vector a real thing, that is, does it represents a state of reality rather than a state of knowledge?

    Do correctness and completeness of quantum mechanics jointly imply that quantum state vectors are necessarily in one-to-one correspondence with elements of the physical reality? In terms of category theory, such a correspondence would stand for an isomorphism (see for example [http://arxiv.org/abs/1502.06676]), so the problem of the status of the quantum state vector could be turned into the question: Are state vectors isomorphic to elements of the reality?

    Daniel Baldomir · University of Santiago de Compostela

        Dear Claude Pierre,

         Quantum Mechanics is compatible with Gravitation everyday, another thing is that we don't know the way to formulate Quantum Gravity Theory. And from my humble point of view in Physics reality is what we can measure in different conditions.

  • Hamed Sharghi asked a question in Materials Science:
    What is the best references or fundamental texts for soliton for solid state or material science researchers?

    I mean acoustic or lattice solitary wave.

  • Pilar Quintana added an answer in RNA Yield:
    Could anyone tell me which is the best method to extract total RNA from in vitro cultured Plasmodium falciparum strains?

    I am working with Plasmodium falciaprum. I am planning to do RNA extraction and cDNA synthesis for gene expression studies. I have the cultured strains in RNA later, stored at -80C. For total RNA extraction, is it best to go with manual Trizol method or Qiagen Blood RNA easy minikit? Also, do we need to do saponin lysis before RNA extraction or not? And can anyone please tell me the approximate RNA yield from 0.2 ml of cultured strains? Thank you in advance.

    Pilar Quintana · Karolinska Institutet

    The RNA pellet gets insoluble after the drying step, so I would recommend the heating step to bring everything into solution ;)

  • Does anyone know a method to combine economic, social and environmental indicators (of sustainable development) into one synthetic indicator ?

    Numerous indicators exist to assess the economic, the social and the environmental pillars of sustainable development (SD). These indicators are usually not comparable but must be combined and weighted together to produce a global SD score. This score can then be used to compare or anticipate planning policies and scenarios. Does anyone know any method or example doing that? 

    Reza Farrahi Moghaddam · École de Technologie Supérieure

    Kenneth...Your point about the relation between CO2 and population deserves its own question/answer thread.

    1. Cautions should be taken when statistical inference based on historical data is carried out:

    1.a Over-aggregation: Population growth could be dominant in Region I while the CO2 emissions are independently dominant in Region C without any direct relation. When aggregated at the world level, they would appear as correlated, which might not be correct.

    1.b Nonlinear regimes of systems: Projection of relations inferred from historical data collected from the linear regimes would be highly off the confidential interval of actual behavior when the system enters nonlinear regimes.

    2. Carbon soot (black carbon) seems to play a role in melt down of ice while it is not listed as a GHG.

    3. Methane and N2O have considerable shares in the global GHG emissions. Therefore, CO2 is not alone.

    4. In general, physical systems do not behave according to the world opinion.

  • Abass Olaode added an answer in Big Data:
    Why does machine learning approaches performance deteriorate when applied to high dimensional data sets?

    In Big Data research field, high dimensionality of data sets is a major problem and one facet of the problem is that the performance of the conventional machine learning approaches, which work efficiently on traditional data sets, deteriorate when they are applied to high dimensional data set. To those who have gone through such experience (applying machine learning to a high dimensional data set), could you please describe the problem from your own perspective and why do you think the performance of your machine learning deteriorated.

    Abass Olaode · University of Wollongong

    I observed this trend in the use of K-means and Self Organising Map for the clustering of 1000 dimensioned Bag-of Word models of images. A simple explanation for this is that there was no prior information to base the choice of features used for the image modelling, therefore the presence of some features adversely affect classification accuracies. I solved the problem using PCA and PLSA to reduce the dimension. the use of PCA or PLSA allows the detection of important features upon which the classification can be based thereby improving the classification by more than 20% of its the values recorded without dimension reduction.

  • Procrustes Rotation and Principal Components Analysis - Literature?

    I'm looking for literature and reference material that will help me better understand Procrustes rotation and Principal Components Analysis specific to multispectral analysis. I'm looking to better understand the process that Baig et al. used in their paper - Derivation of a tasselled cap transformation based on Landsat 8 at-satellite reflectance.

    I understand that they used a method of Procrustes rotation and a Principal Components Analysis to better align the data in a tasseled cap transformation, but I want to understand the process itself. Something that describes it in a visual way as well as a mathematical way.

    Thanks in advance!

    Matthew Sean Galbraith · United States Geological Survey


    Thank you very much for your response. I have already worked through the Crist papers referenced in the Baig et al. paper I referenced in my question and neither of those use a Procrustes rotation method for aligning the data matrices.

    I have read over the Jackson paper and it also does not utilize such a method. I am more looking at finding literature and text that explains the process of Procrustes rotation using multispectral data as an example.

    Hope this adds some additional scope to my question!

  • Ahmed Masoud added an answer in ArcMap:
    Can the Arc Hydro Groundwater in ArcMAP offer a groundwater modeling platform?

    I want to develop groundwater model for an aquifer. Is there any possibility in ArcGIS for modeling, e.g. Arc Hydro Groundwater. What are the capabilities of Acr Hydro Groundwater in ArcMAP? Can it be an alternate for groundwater modeling software e.g. GMS or Groundwater Vistas.

    Ahmed Masoud · Sohag University

    Hi Sir

    to develop Groundwater model you need to have one groundwater modeling software like Modflow, Feflow, GMS or Groundwater Vistas. In ArcGIS you can only activate different tools  for creating and visualizing the model not for run the model. the best example of these tools is Arc Hydro Groundwater which supports MODFLOW 2005 as well as a number of MODFLOW packages. for more information you can see this link : http://www.aquaveo.com/software/ahgw-modflow-analyst

  • Cecilia Teal added an answer in Andragogy:
    Does anyone have information or research access to collaborative (group) self-directed learning, related to Andragogy?

    Adult group learning in the context of no instructor, but through an academic environment?

    Cecilia Teal · EurekaFacts, Rockville, MD, USA

    Hey Jack, I just remembered another resource you may want to check out. Grow (1991) proposed a Staged Self-Directed Learning model and how to teach to the different stages. The 4th and highest stage is "Learners of High Self-Direction" (p. 134) and in this stage, the "teacher" delegates, mentors, inspires, etc, but essentially just sits in the background and monitors progress. Grow comes from a humanistic & constructivist perspective. You might enjoy the article.

    Grow, G. O. (1991). Teaching learners to be self-directed. Adult Education Quarterly, 41(3), 125–149. doi: 10.1177/0001848191041003001.

    Good luck! Cecilia

  • Raju Chowdhury added an answer in Problem Solving:
    Have any solution?

    I am facing a problem to solve the model. Need a solution urgently........ Please suggest me how can I solve it.

    Raju Chowdhury · Stamford University Bangladesh

    COMSOL 4.3

  • Bin Jiang added an answer in Geometry:
    Does the proximity (nearness) of symmetric structures in tilings, drawing the eye to points at infinity, have counterparts in nature?
    The art of tiling originated very early in the history of civilization. The basic idea with tiling is to tessellate a surface, covering a surface with small shapes (tiny triangles, squares, hexagons, octagons, and so on) to create patterns with various symmetries, resulting in a pleasing picture. A plane tiling is a countable family of closed sets that cover the plane without gaps or overlaps (B. Grunbaum, G.C. Shephard, Tilings and Patterns, W.H. Freeman and Co., N.Y., 1957, p. 16). Here are some sample tilings made by artisans and made by nature.

    The first set of Tilings is from the Alhambra at Granada in Spain. For more about this, see
    The second example of a tiling is from M.C. Escher, who visited the Alhambra, marveling at the wealth of decoration in majolica tiles,
    sketching a section that especially attracted him “for its great complexity and geometric artistry”. This first encounter with the tilings in the Alhambra likely increased his interest in making his own tilings (D. Schattschneider, The mathematical side of M.C. Escher, Notices of the Amer. Math. Soc. 57(6), 2010, 707-718).
    For more about this, see
    For example, in May, 1964, Escher completed is tiling called Square Limit. It contains three rings surrounding the center square, forming a grid of self-similar triangles.
    There are many examples of natural tilings (but on a 3D surface instead of the plane). The third example of a tiling comes from nature: images of giraffe parent and offspring (contributed by Hanno Krieger in another thread). In this case, the tesselation of the surface of a giraffe is carried out with many similar shapes (unlike Escher's tilings). Natural tesslations typically provide camouflage for an animal or bird or fish.
    Bin Jiang · Högskolan i Gävle

    Hi, I believe intuitively or naively that there are far more small pieces than large ones for a whole giraffe pattern. I wonder if any researcher had measured the pieces for a giraffe. The sizes would enable us to further examine the ht-index to better understand the complexity of the giraffe pattern. Any suggestions? thanks.

  • Sara Anam asked a question in Tricine SDS-PAGE:
    I have some question about tricine SDS-PAGE?


    I have some question about tricine SDS-PAGE.

    Is it necessary to dilute anode and cathode buffers to final 1x concentration before use?

    can I use coomasie blue  instead of bromophenol blue in sample buffer ?


  • Daniel Leduc added an answer in PERMANOVA:
    Can you report PERMANOVA estimated components of variation (ECV) as a proportion of variation explained by factors/terms?

    Or are ECVs just an indice of how important each term is in the model at explaining the overall variation. In the PERMANOVA output the reported ECVs are calculated from the square root of  (the terms Mean square - residual mean square)/ n. However in a lot of papers the ECV is reported as the percentage of variation explained by each term.


    Daniel Leduc · National Institute of Water and Atmospheric Research

    ECV is definitely not the % of explained variation (i.e., it's nothing like R2). What ECV tells you is the relative importance of different predictors in explaining the variation. For example, if the ECV of one factor is 30, and the ECV of another factor is 15, then you can say that the first factor explains twice as much of the variability in the response variable relative to the second one. You should have a look at the PERMANOVA book for more details.

  • Alain Celzard added an answer in Adsorbents:
    What is the reason for different amounts of different metal ions being adsorbed by an adsorbent?

    If X is any adsorbent with nitrogen functionality, A (transition metal) and B (Carbon family member, say ) are two adsorbates. A and B were separately allowed  to adsorb on the X surface. The amounts of A and B metal ions adsorbed on X's surface were different. Why such a difference???

    Alain Celzard · University of Lorraine

    Several reasons: available pore size, wich is different as A and B probably have different size and geometry, and surface chemistry of the substrate, with which A and B may interact differently. In liquid phase, surface chemistry and porosity have rather comparable (50/50) influences.


  • Murtaza Khan added an answer in CURVE-FIT:
    N-dimensional non-linear curve fitting in matlab?

    I have a data set of twenty-something biological patterns which are listed with some morphological and structural features and I need to find grammatical structure of patterns to be able to find a suitable pattern for some new situation, given some of attribute of new situation be known, what is proper solution for this question?
    Someone has purposed Mathlab curve-fitting but my attributes are qualitive, could curve-fitting be used for n-dimensional non-linear qualitive parameters?

    Murtaza Khan · Umm Al-Qura University

    MATLAB can be use for curve fitting (approximation and interpolation) for N-dimensional data.

    MATLAB Statistics Toolbox and Curve Fitting Toolbox can be use for linear, nonlinear, parametric, and nonparametric models. Please see more details at


    I have uploaded a MATLAB example of Bezier Interpolation in N-Dimension Space at



  • Are there any clear examples of DNA convergence?

    Alan Wilson and colleagues in 1987 famously showed that the amino acid sequence of lysozyme had converged to be the same in the cow and in a leaf-eating monkey, so that molecular phylogeny based on this protein would have erroneously placed these unrelated, phytophagous, mammals on the same branch of the tree. Since DNA evolution is actually less constrained than amino acid sequence (because of “third base wobble etc”), one might expect that there are now many examples of DNA convergence as well.

    Jack D Pettigrew · University of Queensland 

    Visual pigments are notoriously plastic and can change their spectral sensitivity quickly in the face of changes in spectral properties of the environment. A striking example is found in Lake Baikal, where fish living at different depths with different spectral environments have matching visual pigments. So one would expect convergent fine tuning of sequence responsible for spectral sensitivity while at the same time appreciating the deep divergences that provide links to the origins of the visual pigments in ancient taxa, such as those in bacteria.

  • Simran Bhullar added an answer in Troubleshooting:
    Could anyone provide some assistance or a manual for an AMRAY 1830 SEM?

    I'm trying to revive an AMRAY 1830 SEM that I found in our microscopy lab.  I know it worked 5 years ago when the head of the lab retired.  It runs a LaB6 crystal and is equipped with a Robinson Detector.  I can get the column and the electron gun chamber down to 10^-7 Torr and everything turns on. 

    When supply voltage to the gun and then start heating I get really strange emission values.  Sometimes I get no emission but at no point do I get an image.

    Is there a way to troubleshoot the electron beam without taking the gun apart?


    This webpage was last modified around 2 and a half years ago, so may be some contact still works, it is not that old.

    And I could find the manual, hope it helps. 

  • Is anyone using think-aloud protocol (cognitive lab) methodology to investigate test-taking strategies in multiple-choice exams?

    I am interested in why some students can score better on MCQ exams than other forms of assessment while others underperform. It seems to me that a think-aloud protocol (cognitive lab) might cast some light on the test-taking strategies. 

    There seems to be a lot of work around reading comprehension, but I'm having trouble finding anything in health professions education, which is my are of interest.

    Michelle Flood · Royal College of Surgeons in Ireland

    Hi Ronán, 

    Just thought I'd answer from my own experience. I am using a think aloud protocol with collaborators to look at mathematical problem-solving in students from different backgrounds, to see are there variances in metacognitive skills. The data that have come from that study are fascinating (although analysis is still very much underway!). 

    At the same time as I was completing that study a number of students who had repeatedly failed the calculations component of the pharmacy licence exam came to me to seek assistance with their study. This is a multiple choice exam. Having the equipment etc. to hand, I thought I would be useful to try and understand what they were (or weren't!) thinking as they were completing the calculations, the general advice to practice, complete sample papers etc. had not worked! The outcome was very interesting, and not what I might have expected. So, I think your question is very interesting!

    Interestingly, I think that it is consistently identified that expert/novices (as in Ericsson's work already mentioned in an answer to this question, that would also cover some of the heuristics/biases information) in terms of think aloud, in addition to this some really interesting work in the maths education field by a mathematician Matthew Ingils at Loughborough University (e.g. http://homepages.lboro.ac.uk/~mamji/files/JRME_EyeMovements.pdf)  that looks at how experts/undegraduates actually read and look at problems, identifying that individuals appear to actually read the same problem differently. I hope to expand into using that plus think aloud to look further into mathematical problem solving again. That might also add a further dimension into the MCQ-reading/completion strategies.  

    So based on my limited experience and some reading of maths literature, I think your study sounds like it will helpful to try and understand what test-takers are thinking. From my experience of using think aloud as a method, I think it will be apparent from the verbal reports what the students are doing in terms of using heuristics and other problem-solving skills/strategies, and it is also likely (but difficult to capture) that they actually 'see' the problem differently, especially if you are using vignette-based questions.

    Really interesting conversation!


  • Is there any reliable techniques for remote sensed data processing on images obtained with low sun elevation angle?

    Dear colleagues,

    I study plant cover dynamics and I work with Landsat 1-8 images always preferring to overcome all images that have low sun elevation angles in its metadata. But there are some images that are critical to me because of its acquisition data. I need to analyse them because there is no analogous images acquired in more appropriate environmental conditions. But all the techniques I know recommend to be aware of low sun elevation because of presence of significant shadow influence the land cover reflectances.

    Can anybody tell if I can apply any specific methods for such problematic images to obtain appropriate data on plant cover?

    Matthew Sean Galbraith · United States Geological Survey


    I would first start by looking at doing a supervised classification method and include some shadows of vegetation. Afterwards, reclass those vegetative shadows into the vegetation they represent.

    For the second part, there are suggestions that a scaled difference vegetative index (SDVI) works well when dealing with dark soil types and shadows present in off-Nadir images. The publication I've linked explains this process pretty well with experimental results to support the use.

    I will keep an eye out for additional information and pass it your way.

  • Text Classification: How can I train a classifier like SVM using a word list to classify unseen documents?

    Hi. I have a query regarding Text Classification. I have a list of words with the following attributes. word, weight, class. The class can be positive or negative. Weight is between -1 to 1. How can I train a classifier like SVM using this word list to classify unseen documents? An example in any tool is welcome

    Kasper Christensen · Aarhus University

    Hmm, maybe I am misinterpreting your data, but how can a positive class have a weight = -1 and vice versa? 

    Anyways I suggest Rapidminer, WEKA, KNime and Orange. R and Python if you want to program yourself.

  • Can any one give best Method of analysis for flavour by GC-MS?

    Can any one give best Method of analysis for flavour by GC-MS?

    Jorge Ruiz Carrascal · University of Copenhagen

    I think you should fist focus on the extraction method for your volatile compounds. There are quite a few, from SPME, to SDE, static headspace, purge&trap... Then, depending on hte profile of volatile compound of your product and your equipment, you should select those conditions (column(s), injection parameters, flows, MS conditions...) allowing you to have a good identification of key compounds (or as many as possible). As mentioned by Peter, there is not a single best method. 

  • Can quantum entanglement be explained in terms of Einstein-Rosen bridge?

    What do you think on quantum entanglement? 

    Victor Christianto · University of New Mexico

    @Juan: thanks for your answer, but sorry i do not get the distinction between mathematical and physical entanglement. And please kindly send your paper on this issue, if any. Thanks

    @Akira: i have sent a message for you. Please kindly read and response. Thanks

  • Kathryn Bruning added an answer in Nurses:
    Can anyone cite the most current stand on delegation by nurses to LPN's and unlicensed personnel?

    I need to provide citations outside of my state BON.  Thank you

    ANA offers 2 resources to help with this: Delegation and You "provides an explanation of principles" and practice strategies for delegating to UAP, and includes a criteria-based process and flowchart to help; 2013 Principles of Delegation is a background resource. Both available at www.NurseBooks.org/Main-Menu/ANA-You-Series/Delegation-and-You.aspx.

  • Mohammadreza Saraei asked a question in DBT:
    How can we reduce radiation dose in digital breast tomosynthesis?

    Dear my friends;

    As you know the DBT is the low level of radiation dose to breast imaging but its not sufficient relation to typical mamography; thus, I'm gonna to decline dose by methods and algorithms used befor. Has anybody ever similar experiences or any ideas or comments about it?


  • Mohd Arif Khan added an answer in Z-Source Inverter:
    Will the voltage across capacitor and output voltage be equal in z source inverters?

    Capacitor voltage is the voltage across capacitor in impedance network

    Mohd Arif Khan · Fiji National University

    Yes it is...

  • Akira Kanda added an answer in Space Time:
    Do objects move in relation to space-time in GR?

    Generally sympathetic to Carlo Rovelli's pronounced "relationalism" regarding space and time, I still find some of what he says about this puzzling. This question seeks clarification. He argues, in his paper "Localization in QFT," (in Cao ed. Conceptual Foundations of Quantum Field Theory, 1999, p. 215, that "General relativity describes the relative motion of dynamical entities (fields, fluids, particles, planets, stars, galaxies) in relation to one another." This seems true enough. But this is supported by the idea that space-time itself in GR is a "dynamical object," which curves or changes by relation to mass and energy present. But that does not seem a reason to hold that objects do not move in relation to space-time in GR. Instead, it seems that the gravitation field (which determines space- time) is one of the things in relation to which objects move, and consequently that objects move in relation to space-time in GR. In spite of that, Rovelli can be found to say, on the same page, that "Objects do not move in respect to space-time, nor with respect to anything external: they move in relation to one another." Is it inconsistent to think that if objects move in relation to one another, then they move in relation to the encompassing space-time?   

    Akira Kanda · University of Toronto

    Mr. Low,

    You should be thankful for my kindness to keep teaching you mathematics and Physics.

    Please be reminded that all we discuss here is no public record. I do not make strong statement on what I do not know.

    Do you know why we had to wain until it was shown that the Lebesgue became available to conclude that most of the real numbers are irrational numbers. As you of course know, using diagonal argument, Cantor showed that the set of real numbers is not countable. Why this is not enough? His diagonal argument could not show that most numbers are irrationals.

    So, tell me what mathematical physicists know about mathematics and physics?

  • Krezner maturity model assessment?

    we are carrying out a performance analysis of some companies using Krezner maturity model. is it possible to asses each level separately, in other words is it possible to move to assess level 2 and the other levels even the scores of level 1 is found to be very poor (for example less than 300 points)