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  • Sadiye Çetinkaya Çolak asked a question in Borates:
    How can I calculate Non Bridging Oxygens in borate glasses?

    I need to calculate NBOs in B2O3-Na2O-ZnO-TiO2 glass system. Thanks for the help. 

  • Morteza Sadeghi added an answer in Soil Moisture:
    Can you name a soil moisture point between Saturation and Field Capacity? How can I define it for different soil textures?

    I have a number of hourly time series of soil moisture. In these time series, TDR never measured values near soil saturation, but my max values were alway at a certain point between Saturation and FC. So I thought maybe there is really a soil moisture point between Saturation and FC.

    Morteza Sadeghi


    1) Why do you need to name this point? Even FC is a not well-defined concept as it is a dynamic point related to soil drainage and can occur at various pressure heads in different soils.

    2) Are you sure your soils experienced saturation along the wetting-drying cycles? In my opinion, real saturation (or filed saturation) could be reached, while TDR data were not accurate (or TDR was calibrated for gravimetric water content which is always less than volumetric).

    3) Sometimes, saturated water content can be significantly less than soil porosity due to air entrapment, which can be another probable reason for your case.

    Good luck!

  • Evripidis Diamantopoulos added an answer in Methylation:
    Is anyone familiar with the methylation sensitive HRM technique?

    After DNA bisulphite conversion, I can't amplify my PCR product. I designed primers with methprimer but they don't seems to work. Everybody reccomended me to use softwares to design primers but if this is not enought, what could I do?

    Evripidis Diamantopoulos

    Sometimes the problem is more about the primers binding to the damaged CpG dna which is solved  by nested pcr, otherwise try raising the MgCl2 concentration

  • Hans van Leunen added an answer in Special Relativity:
    Can someone re-write the Einstein field equations in such a way that c becomes a global constant?

    I recently showed that the equivalence principle observes this constraint. This fact is trivial because the equivalence principle is based on special relativity alone.

    Therefore, the full field equations must be capable of being re-written in this form. Otherwise, the equivalence principle would no longer fit in.

    So the proposed transform sought is the so far missed "physically correct version" of the Einstein field equations.

    Hans van Leunen

    It is possible to do this for the equations that are used in quantum physics. GRT investigates the same fields, but uses tensor calculus and metrics in order to describe the behavior of these fields.

  • Richard T. Olsson added an answer in Acetic Acid:
    Why do I get no get floating pelicle on top of my G. xylinum culture?

    I am growing G. xylinum, in coconut water (4% sugar  and 0.1% protein ) in glass bottle, with lid 100ml. After 24h I observe some white deposit on the bottom of the bottle but the colour of the coconut water is transparent with no increase in opacity.

    As I am not seeing Nata type consistency after 6 days. What is the best possible way to harvest deposits settling on the bottom (cellulose). I came across some papers suggesting washing with 2% NaOH while others washing with acetic acid and so on.

    I thought I could receive some useful insights.

    I would love to get some idea from people who have worked with glucose, fructose, lactose and sucrose. How does the addition effect production and does different carbon source alter the cellulose crystallinity.

    Richard T. Olsson

    Hydrochloric (HCl) acid will dissolve your entire pelicle if used in concentrated amounts, the same accounts for hydrosulphuric acid (H2SO4), which are the 2 most commonly used acids for extraction of the crystalline contents in your bacterial cellulose pelicle. Sometimes you hear that crystalline cellulose is resistant to acid degradation, and yes, that is the case for weaker acids such as acetic acid, and even so for diluted hydrochloric and sulfuric acid, but I can assure you that if you place any sort of cellulose material in boiling sulfuric acid, there will be absolutely nothing left after 30 minutes and the only thing you can detect/analyse out from your black liquid is carbon based degradation residuals. This was reported already in the 60s when scientist studied the cellulose degradation remains in terms of glucose units from the chain scissoring of the cellulose. I can post you the original scientific works if you would like to have them. :-)

  • Melania Fernández asked a question in Gastrodia:
    Does anybody have access to this article?

    I am trying to locate this article:

    Xu, J. T. & C. Mu. 1990. The relation between growth of Gastrodia elata protocorms and fungi. Journal Acta Botanica Sinica 32 (1): 26-31.

    I will really appreciate if you share it with me.


  • Gledis Guri asked a question in Car:
    Can someone help with info about CO emission factor of different vehicle types in different velocity?

    I want to find the EF (Emission Factors) of different vehicle types (such. car, van, bus, trunk etc.) in different velocity/speed. Or it could be the formula of calculating EF for each vehicle type with velocity variable. I found a lot of information but none of them seem to be compact and they always categorize the vehicles in different ways that is impossible to sum them up all together. 

  • Kelvyn Jones added an answer in Regression Modeling:
    Standard error from coefficient regression model Geographically Weighted Ordinal Logistic Regression?

    I have coefficient regression from estimate parameter model GWOLR, and then i do partial test that coefficient. I use Wald test. Wald test need standard error from parameter/coefficient regression, how equation for calculate standard error. For example, coefficient regression 0.5, 0.8, 0.2, 0.7, 0.6. How i get standard error from that.

    Kelvyn Jones

    GWR inference is tricky because you are fitting literally hundred  of model to the same data - or at least parts of it.

    see http://core.ac.uk/download/pdf/6979782.pdf

    Chris Brunsdon knows ore about this than anyone - and he is very approachable - commitments permitting


  • Masoud Ovissi added an answer in Mineralogy:
    What would be the best approach for finding the Genesis (Origin) of Copper deposit?


    I am making proposal on Aynak Copper Deposit, Afghanistan. The genesis for Aynak Copper Deposit is proposed as sediment hosted syngenetic deposit but there are some points (have Intrusion which is felsic to mafic in composition, also the source of magma is unknown whether it was fertile or not) which I think is epigenetic hydrothermal deposit.

    I have no idea what would be the possible approach (methodology) to find whether it is Hydrothermal deposit or not. Also mineralogical and geochemical investigation of both mineralized and unmineralized rocks would be helpful for finding the hydrothermal source?

    Best Regards
    Wasiq Lutfi


    Masoud Ovissi

    Dear Wasiq, 

    The Part VII which is entitled Aynak Borehole Database needs some user/password for downloading. Maybe you can access them by local contact.

    I have attached the link.

    Truly Yours,

    Masoud Ovissi

  • Teodor Buchner added an answer in LabChart:
    Does anyone know where to find info about the format of 'adicht' files from ADInstruments LabCHart?

    I want to implement a direct reader of adicht files in matlab. Thanks!

    Teodor Buchner


  • Pradipta Bhakta added an answer in Pain Management:
    Do you want to join academic forum on anaesthesia, intensive care and pain management?

    I, an anaesthesiologist from India, presently working in Ireland have created a platform for discussion on relevant academic topic, interesting cases and controversial issues related to anaesthesia, intensive care and pain management. If you feel it is worth to share and gain knowledge, please join the "Anaesthesia Interactive Group" having 11,000+ members with vibrant academic activities which is more than 5 years old. 
    To join the group please click this link "https://www.facebook.com/groups/Anaesthesiainteractivegroup/" and then click the "Join the group" on the right top hand corner of the page. Make sure to make your speciality, area of interest and practice in the public profile so that all members and Admins can know about you. 

    Pradipta Bhakta

    Neeraj: I don't want to open my mouth against these useless morons. But they some to take revenge in my page for sadistic pleasure when they cannot defend academically. This person calls himself a consultant, was a senior form AIIMS with shameful past, now tries to pretend as boss in anaesthesia. I am not bothered ever whatever he and his another useless friend Piyush Mallick does in their group. I keep concentrated in my group. But these perverts comes to attack me wherever they get chance as they have no guts to come to debate with me academically. This person threatened me with phone call from unknown number, with legal complain against me to take action against me in Ireland Medical Council and hacked my account with help of Piyush Mallick several times. They even tried to do sabotage in our group with fake accounts "Des Troy", "Louds Hydrit", "Louds Rohtani" created by Piyush Mallick. My question is that if I do not know anything and my group is useless, why these perverts and useless good for nothing "empty vessels" shouting and trying to do sabotage against me and my group? This person has no comparison with me in knowledge, publication, review and still comes to bark on my wall without my invitation. I have kept silent several times, but these perverts tries to abuse me in all possible way. Thus I have decided to act in tit for tat way. I have filed case of defamation against this one for abusing me personally. 
    You all should know the real picture of this one any Piyush Mallick. 

  • Vesa-Pekka Lehto added an answer in Crystalline Structures:
    Do differences exist between the thin film and powder materials XRD? What are the best methods for examination materials?

    XRD is a method to know the crystalline structure. The materials which be used in substrate deposition it is important to know some parameters about material such that lattice constant , dislocation density and strain.  

    Vesa-Pekka Lehto

    Both XRR and GID measurements can be made with a normal bench top diffractometer. Parallel beam geometry should be used. With XRR you get information about the quality and thickness of the film, also for a stack of thin layers. The surface should be so smooth that you are able to see your own image on it. With GID you get information about the crystallographic parameters of the coating (film). In principle it is like normal XRPD measurement but you control the penetration depth of x-rays into the sample using very small angle for the incident beam. The higher is the incident angle (alpha) the deeper you get information from. In your case, Faisal, the best method is GID, I suppose. If needed, we can make some reference measurements for you.

  • Rachel Shee added an answer in Suppositories:
    Is it possible for cumulative drug release to exceed 100%?

    Paracetamol suppositories made with PEG 4000 and PEG 6000 as suppository bases undergo dissolution test. After 45 minutes, both batches have mean % of drug release that is higher than 100%.

    PEG 4000- 150% and PEG 6000- 120%

    Why does the cumulative drug release exceed 100%? Is there error during measuring of absorbance or is it some form of degradation or hydrolysis of the medicine during manufacture/storage?

    Rachel Shee

    Thank you very much for your help and offer, Anwar.

  • Yurii V Geletii added an answer in Water Splitting:
    How do I calculate the quantum efficiency in a typical photocatalytic water splitting experiment?

    The formula is:

    QE= 2 (number of evolved hydrogen molecules) / number of incident photons.

    1. In particular how determinate the number of incident photons? 
    2. There are some review or papers that reported the typical QE range?
    3. Some papers give the  hydrogen production results in umol/h other in mmol/h other in umol/gcath, what is the correct way?
    4. I have made some exsperiment with the volumethic method but I obtained results of hydrogen rate in mmol/h. A lot of papers are on the contrary in umol/h. Considering that I didn't use a sacrificial agent what mistakes Can I have made?
    Yurii V Geletii

    First, you must to prove that you have both O2 and H2. Second, the volumetric methods is extremely sensitive to the temperature. Third, the amount of the released gas is = {deltaV(ml)/22.7} = mmole. Fourth, QE= 2 (number of evolved hydrogen molecules) / number of ABSORBED photons

    the number of incident photons can be measured from the power of light hitting your solution

    the hydrogen production yield would be better to give in mole/s with specifying the reaction volume. The number calculated as ({H2 in mole/s)/(moles of catalyst)} is defined as an apparent TurnOver Frequency,TOF. 

  • Kelvyn Jones added an answer in Multilevel Modeling:
    What software would you recommend for multilevel modelling?
    I would be very grateful if you might present limitations and unique advantages of multilevel modelling software based on your experience. Thank you!
    Kelvyn Jones

    My experience is that HLM is more easy to use for a novice.

  • Jacek Wydrych added an answer in FLUENT:
    How can I solve the problem with new version of Ansys fluent and the Error during UDF run?

    Hi everyone,

    I have following problem: since now I was working on Ansys Fluent 13 version and successfully I was able to use UDF for evaporation from multicomponent droplet and everything works fine. However, I was forced to switch to next version Fluent 14 and then starts problems. When I want to run simulation I received this error:

    FLUENT received fatal signal (ACCESS_VIOLATION)
    1. Note exact events leading to error.
    2. Save case/data under new name.
    3. Exit program and restart to continue.
    4. Report error to your distributor.
    Error Object: #f

    In previous version it works perfectly right now I cannot run anything. Others simpler UDFs like properties of air after compilation works properly. Have someone have similar problem?

    Jacek Wydrych

    Good day

    You have to instal correct programing environment.

    In version 14 and newer proper is Microsoft Windows SDK 7 and Visual Studio 10 or newer.

    Check this description


  • Hans van Leunen asked a question in Hilbert Space:
    Is quaternionic differential calculus a proper tool for both quantum physics and general relativity?

    Two different kinds of multidimensional differential calculus exist that can cope with parameter spaces that contain elements, which are constituted from a scalar and a three dimensional vector. These sets of differential calculus differ mainly in the choice of the scalar part of the parameters.

    Quaternionic differential calculus uses a parameter space that has quaternions as its elements. Thus, Its parameter space corresponds to a quaternionic number system. This situation is complicated by the fact that several versions of quaternionic number systems exist, which differ in the ordering of their elements. For example, the ordering can be applied via a Cartesian coordinate system, but a Cartesian coordinate system can be ordered in eight mutually independent ways. A spherical coordinate system usually starts from a selected Cartesian coordinate system. It can then proceed by first ordering the azimuth angle or it can start with ordering the polar angle. These angles can be ordered up or down. The radius has a natural ordering. Half of these orderings correspond to quaternions that feature a right handed external vector product. The other half corresponds to quaternions that feature a left handed external vector product. These orderings appear to influence the behavior of elementary objects.

    These ordering choices also appear in the parameter spaces of the other set of differential equations that we will indicate as Maxwell based differential calculus. The Maxwell based equations use a spacetime model that has a Minkowski signature. Where the real parts of quaternionic parameters can be interpreted as representing pure progression, will the Maxwell based equations interpret the scalar part as coordinate time. In comparison to the quaternionic parameter space, the coordinate time plays the role of quaternionic distance. This difference may explain the differences between quaternionic differential calculus and Maxwell based differential calculus, but this is not the fact. Trying to convert the quaternionic differential equations into Maxwell based equations is only partially possible.

    The difference between the two sets is far more subtle, than just a change of the scalar part of the parameter space. The difference between the two sets clearly shows in the second order partial differential equations. The Maxwell based second order partial differential equation is a wave equation, while the quaternionic second order partial differential equation does not feature waves as its solutions. Physics is full of waves, thus this fact might classify quaternionic differential calculus as unphysical. That conclusion is not justified. The clue of the difference is hidden in the Dirac equation for the free electron and free positron. That equation couples two sets of equations. The usual formulation of the Dirac equation uses spinors and Dirac matrices. It is also possible to formulate these equations in quaternionic format and then it becomes clear that the Dirac equation splits into two coupled first order partial differential equations. In this way the Dirac equation couples solutions that use different quaternionic parameter spaces. One of these parameter spaces uses right handed quaternions and the parameter space of the coupled solution uses left handed quaternions. For each of the solutions a second order partial differential equation can be derived via the coupling of the two solutions. This equation is a wave equation! Still both solutions separately obey a regular quaternionic second order partial differential equation. That equation does not accept waves as members of its set of solutions.

    The quaternionic second order partial differential equation  accepts other solutions. For example the homogeneous version of this equation accepts shape keeping fronts as its solutions. Shape keeping fronts operate in odd numbers of spatial dimensions. Thus, a one dimensional shape keeping front can travel along a geodesic in the corresponding field. These objects keep their amplitude. Three dimensional shape keeping fronts diminish their amplitude as 1/r with distance r from the trigger point. The wave equation accepts similar shape keeping solutions, but apart from that, the wave equation also accepts waves as its solutions.

    Both sets of equations do not reach further than second order differentials. As a consequence they cannot handle violent disruptions of the continuity of the considered fields. Also the coverage of longer ranges will require higher order differentials.

    With other words the considered fields will be the same, but the conditions can require methodology, which covers higher order differentials. GRT covers only slightly higher differentials. It neglects the simpler and more localized causes of disruptions of the continuity by point-like artifacts. That should be the task of quantum physics. However, also quantum physics ignores the mechanisms that generate the point-like artifacts, which cause the discontinuities of the physical fields. The equations only describe the behavior of the fields and Physicists seem to interpret the discontinuities as the artifacts that cause the behavior of the fields.

    This outcome shows the need to be able to treat fields independent of the equations that describes their behavior. This is possible by exploiting the fact that Hilbert spaces can store discrete quaternions and quaternionic continuums in the eigenspaces of operators that reside in Hilbert spaces. The reverse bra-ket method can create natural parameter spaces from quaternionic number systems and can relate pairs of functions and their parameter spaces with eigenspaces and eigenvectors of corresponding operators that reside in non-separable Hilbert spaces. This also works for separable Hilbert spaces and the defining functions relate the separable Hilbert space with its non-separable companion.

    + 1 more attachment

  • Kelvyn Jones added an answer in Epidemiological Statistics:
    Can anyone help with age-period-cohort analysis with stata?

    Does anyone knows which is the right form of database for the poprisktime command in stata for age-period-cohort analysis? Could please someone help me with an example?

    Kelvyn Jones

    And if you want to see an argument for the impossibility of separating age period and cohort see






    We - and this is admittedly contentious despite these published articles - do not think that there is an automatic solution because the three aspects - age period and cohort are exactly collinear.

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: BACKGROUND Whilst some argue that a solution to the age-period-cohort (APC) ‘identification problem’ is impossible, numerous methodological solutions have been proposed, including Yang and Land’s Hierarchical-APC (HAPC) model: a multilevel model considering periods and cohorts as cross-classified contexts in which individuals exist. OBJECTIVE To assess the assumptions made by the HAPC model, and the situations in which it does and does not work. METHODS Simulation study. Simulation scenarios assess the effect of (a) cohort trends in the Data Generating Process (DGP) (compared to only random variation), and (b) grouping cohorts (in both DGP and fitted model). RESULTS The model only works if either (a) we can assume that there are no linear (or non-linear) trends in period or cohorts, (b) we control any cohort trend in the model’s fixed part and assume there is no period trend, or (c) we group cohorts in such a way that they exactly match the groupings in the (unknown) DGP. Otherwise, the model can arbitrarily reapportion APC effects, radically impacting interpretation. CONCLUSIONS Since the purpose of APC analysis is often to ascertain the presence of period and/or cohort trends, and since we rarely have solid (if any) theory regarding cohort groupings, there are few circumstances in which this model achieves what Yang and Land claim it can. The results bring into question findings of several published studies using the HAPC model. However, the structure of the model remains a conceptual advance that is useful when we can assume the DGP has no period trends.
      Demographic Research 02/2014; 30:333-360. DOI:10.4054/DemRes.2013.30.11

    + 4 more attachments

  • Stanisław Anweiler asked a question in Porosity:
    Which equation is best for heat transfer during impact of single solid particle to curved surface?

    Single hot solid particle hits the outer surface of the tube. Heat is transfered from the particle to the tube's wall. The equation should include porosity, shape, diameter of the particle. Which formula fits best?

  • Ali Agha asked a question in CNC:
    Free charging- manufacturing journal?

    I need a journal related to Manufacturing field (FB and CNC)?? be free publishing charge & fast (edited review)?      

  • N. Ahmadi added an answer in Regional Climate Modeling:
    Which one of regional climate models can better predict the radiation component for Iran?

    regional climate model or global climate model

    N. Ahmadi

    thanks L.Alvarez

  • Janet Hanson added an answer in ESL:
    What are the theoretical and empirical relationships between developing a multicultural view in schools and a growth mindset?

    Researchers recently focus on studies for developing growth mindset in schools. A review of the literature suggests the processes and variables involved in a growth school mindset may be similar to those that develop a group open to a multicultural view in schools. Does anyone have articles referencing studies connecting multicultural views in schools or ESL teacher development with Dweck's concepts of growth school mindset? Thank you in advance.

    Janet Hanson


    I have read your paper and would like to respond. You stated, "One can speak of teaching methods and principles as separate things, but it is necessary to bear in mind that they never act independently of each other" (p. 4). This is a core idea as it highlights the difference between Eastern and Western pedagogical ideologies. Since early western philosophers proposed dualistic approaches to viewing the word, the western system of thinking has progressively and actively socialized teachers into a compartmentalist approach to presenting knowledge to students. (if I may take the liberty to suggest others may also view dualistic philosophies as having influenced a "system" of thinking identifiable in western pedagogy)

    Some researchers have made efforts to explore differences between western and eastern mindsets as these relate to how individuals learn. Eastern worldviews "see" context more readily than objects while western worldviews promote the selection and memory of objects. Eastern worldviews are tend to view communal relationships in the context while westerners process using an individualistic lens. This results or is caused by compartmentalization in the western worldview and ultimately the fundamental attribution error of western thought. This means that westerner thought processes will impute causation to an object with less regard to the context the object (person or thing) is set within. While eastern thought processes more correctly attribute causation having taken into consideration the context and relationships between the objects viewed.

    I relate this to your comment of the error prone instruction methods of didactic, dualistic approaches to teaching methodologies which you seem to suggest can be remedied through a context-rich, relational approach to engaging study learning.

    Thank  you for your deep insights and the clarity with which you provide this information to the reader.

    Kind regards,


  • Ricardo Guzman added an answer in Philosophy Of Science:
    What are the best references in fictional literature to teach Philosophy of Science?

    I intend to use classical books and stories to explore conceptual topics on Philosophy of Sciences. Can anyone suggest some references?

    Ricardo Guzman

    I believe you may be interested in the novel An Instance of the Fingerpost by Iain Pears. You will find characters that actually are historical figures like the mathematician John Wallis, the philosopher John Locke and the scientist Robert Boyle.

    A contrast portrayed in the novel is, on one hand, a philosophy based on ancient and medieval knowledge, and, on the other hand, the scientific method that was beginning to be applied in physics, chemistry and medicine

  • Steffan Noe Christiansen added an answer in Hybridization:
    Why don't I get any shift when performing EMSA for investigation of TBP:TATA interaction?

    I'm performing EMSA in order to determine the Kd between human TBP and different 26-bp doublestranded oligos containing TATA-boxes. However, I've struggled a lot to get any shifts even though identical oligos earlier have been proven to interact with TBP with high affinity. I use the Gelshift™ Chemiluminescent EMSA Kit(Active Motif), recombinant TBP(Active Motif) and oligos synthesized by IDT.

    The binding reactions contain 20 mM HEPES-KOH (pH 7.6), 5 mM MgCl2, 70 mM KCl, 1 mM DTT, 100 mg/ml BSA, 0.01% NP-40, 5% glycerol. Interaction has also been tested in absence of KCl, DTT, BSA and with the binding buffer provided by the kit instead of the HEPES-KOH. I have used different concentrations of DNA (0.1-100 nM) combined with different concentrations of TBP (1.25-125 nM). The bindings reactions have been incubated in either 30 min or 3 h at RT (TBP dimers has a quite slow disassociation constant and, hence the long incubation time was tested) before loading.

    The gels used have either been 4% or 6% continuous native PAGE run in either Tris-glycine(1x) or TBE(1x and 0.5x). Buffers are not pH-adjusted. I run the gels in fresh buffer at 4°C with a constant voltage of 175 V.

    I have had some initial problems with oligo hybridization and, therefore I run all my experiments with a ssDNA control to rule out that lacking oligo hybridization is the problem.

    qPCR have been performed on anti-TBP immunoprecipitated sonicated genomic DNA and the regions containing the specific TATA-boxes of interest were amplified compared to control regions, so it seems like the TBP still have sufficient ability to bind the TATA boxes (at least when I'm performing immunprecipitation).

    TBP has a quite high pI (9.8) so I've suspected that the net positive charge of TBP per se should be the problem. However, when bound to a 26 bp oligo the complex should have a net negative charge.

    Does anyone have any suggestions for how to solve the problem?

    Steffan Noe Christiansen

    Sebastien, did you experience that the loading buffer directly interfered and reduced protein:DNA association? I have not considered at all that the loading buffer could be a problem.

    I'm quite sure that the TBP is active. As mentioned earlier, the TBP has the ability to bind to the specific TATA-boxes in DNA immunoprecipitation with sonicated gDNA. Regions containing the speific TATA-boxes are amplified compared to regions without TATA-boxes when I perform qPCR on the immunoprecipitated DNA.

    I have not excluded the possibility that some PTM may be inhibit the binding. The protein is expressed in E.Coli with a N-terminal His-Tag. When I run the protein on SDS page it has the expected size and there is no other bands.

  • Barbara Sawicka added an answer in Complicity:
    It is said that ignorance is bliss!

    Is it really a bliss in the complicated complex world.

  • Deon Bezuidenhout added an answer in Electrospinning:
    What is the easiest way to produce unidirectional fibrous membranes using electrospinning?

    I am using the polyurethane as my polymer fibers. 

    Deon Bezuidenhout

    We have spun various polyurethanes and could always produce oriented (alligned) fibres by sufficiently increasing the takeup speed but increasing rotational speed and/or increasing collector diameter.  Another way is to spin onto a collector with sharp ridges; the fibres will tend to span the gap between ridges in an alligned manner, but this is normally limited in length/distance.  What polyurethane are you and which conditions (concentration, solvent etc)? Regards. Deon

  • Rachelle Alterman added an answer in Empirical Study:
    How can we measure the impact of 'Shadow Economy'?

    I am willing to explore an empirical study on shadow economy in Nepal. Nepal currently experiencing double obstructions: one from the 'Madhesh based parties through road strikes; another from the Indian unofficial blockade. As a consequences the supply is heavily dropped and the price take-off. Now, there is substantial growth of 'shadow economy' in Nepal. However, Government of Nepal has intervened the growing 'shadow economy' but the actions are not enough to stop the new growing rom environment for 'shadow economy' as there is consistent demands from overwhelming public specially goods are fuels and energy like petrol and cooking gas. 

    In order to explore the growing market failure, I am willing to know how to measure the market inefficiencies and how to measure 'shadow economy'? 

    Rachelle Alterman

    The "shadow economy" is a term suggestive of developing countries where the governance system is weak, and tax controls are selective.  however, in recent years the so-called "sharing economy", more typical of advanced-economy countries, has some (not all) characteristics of a shadow economy.  You may wish to look at the still-embryonic empirical and conceptual literature on this topic.

  • Daniela Vandepeer added an answer in Self-Directed Learning:
    What factors could be predicted by a positive disposition towards learning in adults ?

    I am looking for subjective and objective factors that could be predicted by an above average disposition towards learning (self-directed learning, lifelong learning, etc.) in adults.

    In your mind, what those factors could be ?

    Daniela Vandepeer

    I tend to agree with Paul.

    Also, contextual factors contribute to attitude change.

    You might find these links useful as different perspectives/ideas:








  • Montserrat Hernández-López added an answer in Likert Scale:
    Which Likert scale should I prefer that of 1-4, 1-5 or 1-7?

    Hi everybody!

    I'm making a questionnaire for my students about my new teaching style. My question is about the best Lickert scale that I can use in order to they evaluate some statements: 1-4, 1-5 o 1-7? I have read about this, but there are advantages and disadvantages in each of them. Can anyone help me out?

    Thank you in advance.

    Montserrat Hernández-López

    Hi Witold.

    I think that my final decision will be between scale of 5 or 7. When reading the documents that Khandoker attached kindly me, I will make the right decisión.

    Thank you so much!