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  • Shayan Mostafaei added an answer in Alpha:
    What is the solution to a low Cronbach's alpha (0.5)? Is it possible to continue with a low value of 0.5?

    The study is basically qualitative in nature. In order to provide a justification for the adoption of this model, a sample of 150 respondents from this model is compared with the same number from the other model. The Cronbach's alpha is calculated to be 0.5. Can I report the results specially when the findings of the study mainly rests on the cases?

    Shayan Mostafaei · Tarbiat Modares University

    no, It is not possible.

  • How can I mathematically model the behaviour of the humans?

    Any suggestion/resources are appreciated.

    Yes Andras,  but have you left your mind at home as well?

  • How do you integrate different sources of errors in hydrological modelling?

    Dear all,

    Assuming that we identified different sources of errors in hydrological modelling. Lets say rainfall is estimated with its error(uncertainty) band, the ET is estimated with its error(uncertainty) band, and other inputs (model parameters) of the model also have been estimated with its errors,  what are the  state of art in propagating all the errors  into the discharge uncertainty.  Unlike the rainfall and ET which is instantaneous each-time step errors, there will also be some initial condition error, that i want to include in the error propagation . So what is the best way to include all of these ? 

    Best regards 


  • Muhammad Umair Ali added an answer in Crystallinity:
    Can anybody please explain to me the effect of difference in ionic and atomic radii of dopant and host material on crystallinity and other factors?

    We have synthesized undoped and Fe doped La2O3 nanostrcutures. The crystallnity of La2O3 is increased by Fe doping. We also synthesized undoped and Fe doped SnO2 nanostructures. In this case, crystallinity of SnO2 decreased by Fe doping. Can any body please explain me the reason of this increase or decrease in crystallinity by Fe doping? The ionic radii of Fe is 76 pm, Sn is 71 pm and that of La is 117 pm. Does crystallinity vary due to change in ionic radii?

    Muhammad Umair Ali · International Islamic University, Islamabad

    @Mehmet S Celik  Sir I am very thankful to you as well as Dr. Ovecoglu for such a nice and detailed answer. Can you please provide some references of this reasoning for purpose of citation? 

  • Is there any good source for a MRI image of liver?
    Working on the project of scaffold designing.
  • What the different between Mutual information and information gain?

    Dear all,

    Conceptually, what the difference between Mutual information and Information gain?

    I have tried to do an exercise which is involved the mutual information theory, However, after i ended up the calculation for MI and tested as well using the Information Gain theory by referring the same figures from a sample table, i got the same value between MI and IG. Can anyone here brief me the keyword to differentiate these both theories?   

    Francisco M. Garcia · University of Massachusetts Amherst

    I've seen different sources using the term information gain to mean either MI or KL-Divergence. You should look into how IG is defined, mutual info I(X;Y) = H(Y) - H(Y|X) while the KL Divergence D(X||Y) = H(X,Y) - H(X). But from the description you are , it looks like IG might be being used interchangeably with MI.
    Again, double check the definition of your sources to see if this is the case.
    I hope that helps.


  • Dorian Aur added an answer in Cognitive:
    What is the best approach to study the Problem of Consciousness?

    The Problem of Consciousness:


    Cognitive approaches:


    Are there any other approaches?

    Dorian Aur · Stanford University

     Dear Jonathan  "the role of compression in air"  was written somewhere  in the paragraph " If you can indicate where I have gone wrong in my analysis I would be only too pleased to learn something new. But you have not raised a counterargument yet. "

    Have you deleted it?

  • Gertrudis Rojas added an answer in Phage:
    Phage concentration by PEG 8000 and NaCl?
    Generally I gave PEG treatment for 1 hour in 40C. It works fine. But for my work schedule it is better to use O/N PEG treatment. Is there any toxic or other effect of PEG which decreases the phage titer? Because in some source I found long time incubation is not better for phage isolation.
    Gertrudis Rojas · Center of Molecular Immunology

    I have eventually left my phages overnight in PEG precipitation (on ice) without any problem to complete purification next day. 

  • Ellis C O'Neill added an answer in SDS-PAGE:
    What percentage of SDS-PAGE is suitable for running of low concentration proteins?

    For example 100 ng/ml.

    Ellis C O'Neill · University of California, San Diego

    Try the protocol below, it seems fairly comprehensive to me. For loading a single lane in your PAGE gel, if staining with coomassie, precipitate 100 ul (10 ng) of your protein. Resuspend in 10 ul and load all of this on the gel. This should give you a band visible by coomassie. (TCA is trichloro acetic acid)


  • Walter Filho added an answer in Parasite Egg Count:
    Can anyone suggest a protocol for effectively analysing samples of feces in small amounts (1g aprox) within a laboratory?

    I am looking into parasite loads within a species of lemur native to Madagascar and have collected over 100 samples of feces but each sample is only around 1 g, so I need to find a method to effectively analyse the samples without losing loads of eggs. Does anybody have a method that is good for analysing small samples for parasite egg counts?

    Walter Filho · Federal Rural University of Rio de Janeiro

    In our laboratory, we use to McMaster a quantity of 4g feces, and depends on the condition of feces, diluted with 60 ml of saturated solution of salt or sugar. To simply give diagnostic positive or negative, we use the method of Willis.

  • Sardar Asad Ali Biabani asked a question in Happiness:
    As a Project Manager what steps will you take to win back the trust of stakeholders with the limited resources available to see the project deadline?

    In line, a stakeholder is usually an investor in your company whose actions influence the result of your business decisions. Stakeholders don’t have to be equity shareholders. They can also be your employees, who receive a stake in your company’s success and incentive for your products to follow. They can be business partners, who rely on your success to keep the supply chain moving. Every commercial enterprise needs a different approach to stakeholders. The roles of stakeholders differ between businesses, depending on the patterns and duties laid out at the foundation of your companionship or as your business evolved over the long time.

    A project is running behind schedule and its stakeholders are not happy with the project scope and demands a change. As a Project Manager what steps will you take to win back the trust of stakeholders with the limited resources available to see the project deadline?

  • Artem Gerasimenko asked a question in Cyanobacteria:
    How can I easy differentiate green and blue-green algae under light microscope?

    Especially I have problems with recognition coccoid forms of cyanobacteria.

  • Andreas Lampis added an answer in Atomic Physics:
    Is it possible to apply the Pound-Drever-Hall technique using the transmitted rather than the reflected signal from a cavity?

    I was wondering if it is possible to apply the Pound-Drever-Hall technique using the transmitted rather than the reflected signal from a cavity? Is there any limitation preventing you from doing this?

    Andreas Lampis · University of Birmingham

    Thank you both for your response. 

    Gregor, thanks for bringing this paper into my attention.

    From the paper:

    - In reflection, the information is obtained by comparing the amplitudes of the sidebands (phase directly related to the phase of the incoming light) with the amplitude of the central line which is time delayed. Because of the antisymmetric structure of the sidebands, this beat gives an error signal proportional to the phase variation of the incoming light for times smaller than the storage time.  The transient response is then linear to t.  

    - In transmission, the information is given by the light directly transmitted by the cavity. The error signal obtained is proportional to the cosinus of the phase difference between the transmitted beam and the time-delayed beams. The phase dependence of the transient response is then quadratic.          

    - In both, transmission and reflection, the transfer function (derived in the paper) for low frequencies is proportional to the finesse of the cavity. For high frequencies though, the transfer function in transmission, decreases with the finesse. This does not happen in reflection.  

  • From which magnetic measurement can we know about the uniaxial anisotropy of ultrafine iron oxide nanoparticles?

    For nanoparticles with cubic anisotropy, we got the reduced remanence of 0.5 from the M-H curves. In case of nanoparticles with uniaxial anisotropy how can we determine the reduced remanence?

    A. A. Timopheev · University of Aveiro

    @Kakoli Bhattacharya

    The enseble should be diluted as strongly as it posssible to avoid the demagnetization field to influence on the magnetization loop. One also should fix the particles randomly oriented at zero field and desirably at T>Tc in some nonmagnetic matrix so they will not be able to rotate during magnetization process - otherwise the hystersis loop wiil be distorted and further analysis will have no much sense.

  • Govinda Sharma added an answer in Flow Cytometry:
    Is the compensation value set in a flow cytometry experiment dependent on the brightness of the fluorophore?

    If I've got a compensation control that is much brighter than my experimental sample, is the compensation value derived from this control still valid? Intuitively, I feel that more fluorescence intensity should equal more spillover signal relative to the dimmer sample. However, most protocols I've come across recommend that the compensation controls used should be as bright as experimental or brighter.

    Govinda Sharma · BC Cancer Agency

    More detail:

    My experimental fluorophore is an EYFP fusion expressed as part of a bicistronic gene. The gene was stably incorporated by lentivirus. My compensation control is unfused EYFP expressed from a transiently expressed plasmid. The combination of fusion, bicistronic expression, and relatively lower copy number accounts for the difference in brightness.

  • My polymer has refractive index n20/D1.4666. What is actual value of refrative index from this descriptive ratio??

    Nonionic surfactant has refractive index of n20/D1.446. But i could not understand from this description that what is actual value of refractive index?? Any idea ?

  • Paul Naphtali added an answer in Water Sampling:
    How can I optimize the flow rate of my water sample and standard nitrate solutions through the cadmium reduction column?

    Hi all,

    I am currently attempting to formulate a publication-quality standard curve for the quantification of nitrates in a water sample with the cadmium reduction method. I have purchased a cadmium reduction column pack from Kimble-Chase as suggested by the authors of Standard Methods for the Examination of Water and Wastewater 22nd Edition.

    The water compendium states that the water sample will be passed through the column at a rate of 7-10 mL per minute once the copper-coated cadmium granules are added. However, my samples are flowing through the column at less than half the minimum rate.

    I was wondering if you all had any advice for increasing the flow rate of the sample through the column with the copper-coated granules of 30-80 mesh.


    Paul Naphtali · McMaster University


    I already checked for bubbles. I made sure there were none. I added the water into the column first. I then coated the cadmium granules with copper sulfate solution. Afterwards, I introduced the granules into the water-filled column. No bubbles were formed after that step either.

  • How can the management culture be measured? I.e., what are the parameters?

    During one debate, in which I participated, there was quite a lot of controversy about the measurement of the management culture. I.e., is it possible to measure the management culture in levels (e.g., a very high level of the management culture in the organization, high, medium, low, very low level); is it possible to measure the management culture in degrees (e.g., a high degree of expression of the management of culture, etc.)?

    If you’ve read any scientific publications on this topic, I would be very grateful if you could share.

    Ierardi Enzo · Università degli Studi di Bari Aldo Moro

    Destiny is not the result of chance, it is a matter of choice;
    is not something that we have to wait, but that we have to reach.

  • Guosheng Shao added an answer in Doping:
    How can you calculate the % of hetro atom doping(H,N) or whether it get substitution inside the semiconductor metal oxide like TiO2?

    Generally we will say if less than 1% hetroatom is doped than its a doping but if it is more than 1% than its a substituion and it will behaviour will change but would you calculate it XRF will not give information about less than 1% . How can we know how much hydrogen is there??

    Guosheng Shao · University of Bolton

    Either doping or alloying refers to incorporation of an alien atom into a host material. Conventionally doping refers to low amount of incorporation and alloying refers to higher amount, though it is hard to have a boundary to tell the two cases from each other.

    It might be self-consistent to class the two cases in the following way:

    1) doping is to induce n- or p-type conductivity to a prestine semicondutor phase;

    2) alloying is to induce significant change in the energy band structure

    For wide gap semiconductors, the intrinsic carrier concentration is close to zero and thus all ionised centred are induced by alien incorporation, and much higher amount of such incorporation is needed to achieve doping effect. One note that effective doping of TiO2 needs several atomic percent to induce effective conductivity.

    Experimentally, it's rather hard to analyse Hydrogen in a material due to its single shell characteristics. Mass spectroscopy such as SIMS can detect H in solid phases, but accuracy can be a problem.

    Hydrogen Forward Scattering Spectroscopy can be used to quantify hydrogen profiles in thin films. Neutron scattering can offer insight about where H is in the host phase. 

  • How to assign charge in autodock?
    I would like to assign charge to heme iron center, for some reason the MVT assigns zero charge to it.
    Can anyone explain to me how autodock vina deals with electrostatic interactions? From what I understand , vina ignores charges. Is that true?
    Can anyone suggest a way to do molecular simulation and check the structure whether it is correct or not?
    Nisreen Merza Shumayrikh · Simon Fraser University

    Thank you so much!

  • Antonio Toniolo added an answer in IL-8:
    Why do my MM6 cells produce high levels of IL-8?

    Our MM6 cells seem to differentially produce high levels of IL-8 without any stimulus, whereas levels of IL-6 and TNF are not elevated. Can anybody explain this ?

    Antonio Toniolo · Università degli Studi dell'Insubria

    MM6 cells, as human monocytes, may produce IL8, either spontaneously, or after stimuli such as LPS and oxidized lipoproteins. These cells, should be used with LPS-free reagents and media supplemented with 10% fetal calf serum that has been depleted of apolipoprotein B-containing lipoproteins by ultracentrifugation. Alternatively, try to grow the cell line in "serum-free medium" (there are several types in commerce).

  • Is there any eco-friendly bacteria like Bacillus thuringiensis which can be used in multipurpose matters?

    Bacillus thuringiensis is a bacteria that is used in genetic, agricultural and ecological purposes. I need the name of any other bacteria that has also multipurpose roles in the environment.

    András Bozsik · University of Debrecen

    Dear Shankhadeep,

    The number of such bacteria is very high. Here you are some of them:

    Acidophilus bifidus belongs to the most common types of good bacteria found in yogurt, miso, tempeh and probiotics supplements. It has many health benefits, including easing digestive problems, treating vaginal infections and reducing the risk of heart disease.

    Streptomyces spp. (e.g. S. avermitilis, S. grisea) are used in manufacturing of antibiotics.

    Rhizobium spp. play an important role in nitrogen fixation. They live in symbiosis with Fabaceae.

    It is sufficient to write in Google: useful bacteria

  • Nicolas Girerd added an answer in Heart Rate:
    For the purpose of HRV (Heart Rate Variability) analysis, we need a recording of ECG traces for at least 5 minutes, is this true?
    ie. If I would like to see the influence of static magnetic field at 1.5T or 3T to HRV, How long should I record? And which parameters could best satisfy the short-term HRV analysis?
  • Jacob Yu added an answer in Waste Products:
    Are Dr. John Todd's "Living Machines" a viable way to treat wastewater on a large scale?

    They are supposedly a way to treat wastewater without using chemicals, but instead by creating an "ecosystem", whose constituent organisms filter the water. I gathered from this paper http://www.uvm.edu/rsenr/nr385c/resources/documents/The%20design%20of%20living%20technologies%20for%20waste%20treatment.pdf

    that "the ideal closed system as having three major components or subsystems. It consists of a sunlight-based,
    photosynthetically driven system that is connected to an animal consumer component, which in turn, is connected to a detritus/bacterial system.
    Our experience supports the Adey and Loveland (1991) requirement of a minimum of three distinct subecosystems. We have found it is best to house the subsystems in distinct cells separated in space but connected by flows." 

    He has a company: http://www.toddecological.com/eco-machines/

    which installs these for a fee....Can anyone comment on if this is a viable method for the future? It seems almost "too good to be true" - an all natural way to deal with the waste products of society purely relying on "natural" processes..

    Jacob Yu · Boston University

    Fascinating answers, thank you all, will read further on the leads you all have given me thus far..

  • What is the definition of phytotherapy?
    How a research domain is theoretically defined or framed might influence how it is practically perceived by citizens or experts from other research domains. This can be illustrated with the definition of ‘Phytotherapy’ often defined as ‘treatment with plants or plant components’. Following recent estimates of ‘O.M.S.’ (<2013), ca. 20.000 plants have medical action and 1.200 plant species are claimed to be used in pharmaceutical treatment out of >270.000 plant species currently identified in taxonomic Botany. Pharmaceutical treatment involves digestion or physical penetration of molecules or plant components targeting physiological or neurophysiological processes. However, psychologists guiding depressed people might argue that flowers or any vegetation used to decorate gardens, houses or green space also involve ‘Phytotherapy’. Perception of green space, including park or forest landscape, can reduce mental stress therefore improving health status. Moreover, diet specialists argue that consumed fruits contain all ingredients essential for physiological and, why not, mental performance. Thus vegetable consumption could be defined as ‘Phytotherapy’ accepting vegetables form an essential part of the human diet influencing and improving health status. The question then is why those that defined ‘Phytotherapy’ made a distinction between plants consumed or digested and plants observed or perceived? Plants consumed or digested and plants observed or perceived are just acting on different parts of the human body, either via physiology (energy, metabolism) or neuron system receptors. Any plant component improving health status could thus by definition be placed under the heading ‘Phytotherapy’. Phytotherapy therefore would involve all visual stimuli lowering stress thus reducing risks of depression or mental disease, all vegetation stimuli or components acting directly on physiology, neurology or immunology, or all plants or plant substances changing external appearance to improve social interaction and integration. It does not exclude that actions of vegetation improving health are individual-specific, whatever the plant components involved. Some people might consider wildlife herbs as waste to be removed from urban green space, whereas others might consider the same wildlife herbs as essential parts of the urban landscape reducing mental stress. Some people might also be more or less allergic to one plant component, even those currently considered as treatment in pharmaceutical research. This implies that the definition of ‘Phytotherapy’ would be individual-specific. Nearly all plants may have phytotherapeutic action in at least one individual, just depending on scales of analysis and application defined.
    Marcel M. Lambrechts · Centre d'Ecologie Fonctionnelle et Evolutive, Montpellier, France

    Do you think that effects of phytotherapy on healing express seasonal variation?


    Is it possible that the same herb treatment  might be more /less efficient when combined with phototherapy, e.g. therapy under long (e.g. summer) versus short (e.g. winter) day lengths?

  • Arun Nadaradjane added an answer in Rhodamine 123:
    What is the role of rhodamine 123 in detecting apoptosis?

    Thanks in advance.

    Arun Nadaradjane · Université de Reims Champagne-Ardenne

    That was really helpful, Sabarish Nagarajan. Thank you.

  • Peter T Breuer added an answer in Turing Machine:
    Is there a restriction in PvNP to 0's, 1's, and NAND?

    If I am not mistaken, anything we can compute in a Turing Machine is reducible to 1's, 0's, and only one logical operation: NAND.  I can't see how cycles can be counted any other way.  Is that a requirement in the formalisms for stating the PvNP problem?

    I suppose the alternative is that the nature of the steps does not matter, because we are simply interested in scaling.

    Peter T Breuer · Birmingham City University

    The usage here is based on time = cycles of a Turing machine. There's no point in distinguishing the two concepts and no way of confusing them because there is no way of looking at a real Einsteinian Universe space-time clock in this context. So we might as well say "polynomial time", meaning "that would take nk cycles of a Turing machine", for some k. It's shorter.

    Besides, we want to distinguish from "polynomial space [memory]" sometimes! "Polynomial time" implies "polynomial space", but not vice versa, if you care.

    So this super-duper hyper-uber machine being discussed has polynomial time cycles :-). I.e., its nth cycle does stuff that would take a Turing machine nk cycles, were it to be so inclined ... just pull us up and make us say "would take a Turing machine nk cycles" whenever "polynomial time" has been written instead!

  • Didier Andrivon added an answer in Physics:
    Do you think that scientific research is more or less efficient now than in 1900's?
    In the first half of 1900's (1900-1950) most of modern physics theories and discoveries were achieved (quantum physics, atomic physics, nuclear physics, high energy physics, astrophysics, solid state physics, solid state electronics, microelectroics, integration...) with much less means, equipments and funding than now.

    In the second half of 1900's (1950-2000), most of the discoveries were more or less an improvement or a limited innovation with respect to what was already found before 1950. At the same time the funding being put in research are increasing drastically.

    Do you agree that there is a decreasing efficiency of scientific research worldwide which started at the end of the 1900's and is more evident in 2000' years?
    Didier Andrivon · French National Institute for Agricultural Research

    Hi all,

    A key point to properly (try to) answer the original question is to decide how to measure efficiency. To me, efficiency is a ratio between the outputs and the inputs. The outputs (papers, technologies such as semiconductors or nanoparticles in physics, gene sequencing methods in biology, new products such as smartphones, 3D printers or space shuttles...) are way more numerous now than they were at the turn of the former century; so are the number of scientists worldwide, and so is also  the overall amount of money invested in science ( and not just in academic institutions, but also in companies that rely on science for innovation). I don't know if we have the correct estimates for all of these variables, but theoretically speaking, and provided there is a consensus on the indicators themselves, efficiency might well be measured and compared. This has probably been attempted?

    Another key issue is picking the right indicators, and in particular to decide which outputs are indeed valuable. An extremely high proportion of all papers in refereed journals is never cited during the first five years following their publication - which means they are 'detrimental' in terms of efficiency because producing them consumed resources that might have been used  for 'productive' science ( note the quotation markls please!).

    So, I think we can state for sure that science is more productive now than it was a century ago, but I am not so sure about it being more efficient...

  • How to model disjoints constraints in linear programming?

    We have two constraints: xij- zuv >=0 , zij - xuv >=0  where xij , zuv, zij and  xuv are continuous variables. We would like that one of the two constraints will be satisfied, so how to model this disjoint constraints?

    Michael Patriksson · Chalmers University of Technology

    Introduce a binary variable y_ijuv, and write

    x_ij - z_uv >= -M y_ijuv

    z_ij - x_uv >= -M (1- y_ijuv),

    where the value of the scalar M is large enough so that when y_ijuv =1 the second constraint is redundant, and correspondingly when y_ijuv = 0 the first constraint is redundant. This is always possible if the variation of the x and z is bounded.

  • Brigitte Gontero added an answer in FPLC:
    Can gel fitration column be used for seperating two proteins of 10kd difference?

    I need to do gel filtration with a complex and third protein. Thinking of doing FPLC combined gel filtration column. The complex is made of two proteins of 50KD and 15 kD. Third protein is 36kd. I am hypothesizing that 36Kd protein replaces 50KD from the complex, by interacting with the 15kD protein. Now my question is, are there columns which can distinguish, 36 and 50Kd proteins....how to find which will be the best column for my protein

    Brigitte Gontero · Institute of Microbiology of the Mediterranean

    I will suggest if you want to check protein protein interaction using chromatography, to run anion exchange chromatography. If your complex co-elutes with the 36kDa protein, it will be another evidence (of course could mean they have the same charge, if you know the sequences you coudl calculate the isoelectric point of the complex and of teh 36 kDa protein). Thsi chromatography based on charge separation might help to discriminate, Coelution is one of the criterium for protein protein interaction.

    Problem using high length column is that you might dilute your sample and as dilution favors dissocitaion you might be in trouble.