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  • Irene Npl added an answer in Educational Leadership:
    Does anyone know any research papers on the low representation of women in educational leadership and the barriers they face?

    I am looking for the factors that prevent qualified women from seeking leadership positions. 

    Irene Npl

    Mrs Kaparou, thank you! I already used your paper in my literature review. It was very useful! 

  • Peter Bernhardt added an answer in Pollination Biology:
    What's the standard level of % seed set for self-incompatible, animal-pollinated flowers in natural conditions?

    I am looking for information on how much % seed set is the “standard” level for self-incompatible plants in natural conditions. Does anyone know useful references or compiled data sets etc. from which I can derive a quick answer to this?

    Peter Bernhardt

    I don't consider your question naive at all, Mr Ohashi.  It deserves exploration beyond the usual review papers.  We must be honest.  So many of those papers attempting to combine SI and animal-pollination used different techniques for assessing SI.  Frankly, placing a flower in a bag doesn't really tell you that it's SI.  It does tell you if the flower is capable of mechanical self-pollination.  Only hand-mediated pollination experiments and microscopy tell you, eventually, where is the site of self-recognition/rejection and the natural conversion rate of ovules into seeds following cross vs. self-pollination.

    I think I know what you wanted to really ask.  Were you asking whether fruit and/or seed set should be lower in a self-incompatible species vs. a self-compatible species?  After all, since most SI species studied have a limited number of S alleles cross-pollination results should be lower in an SI species because siblings and parents share one or more of the same alleles.  The answer should be a tentative, yes, but it needs to be tested more frequently.  Kenrick et al. did so as they hand-selfed and crossed between and within populations of Acacia retinodes.  Based on the foraging of the pollinators and the "relatedness" of shrubs in each site the act of insect-mediated pollination was high but the conversion of ovaries into pods was low due to shared alleles.  Virtually all Xerophyllum tenax flowers can self-pollinate but there a virtually no seeds.  Ovaries swell up in a false pregnancy

    Of course, there's a lot of variation in reproductive success in self-incompatible species based on habit, life-span/life-history, ovule number/ovary, pollinator spectrum, number flowers/inflorescence, climatic conditions etc. but we should be able to see some "corralations" when species in the same lineage are compared.  Look over my old papers on Amyema.  It's a genus of obligate, stem parasites.  We found that the SI species had a lower conversion rate of flowers into fruit compared to partial SI species and self-compatible species.  This correlated with the diversity and life-spans of host tree or shrub species (but this also depended on the number of flowers/inflorescence).  We even found variation in breeding systems within one species, Amyema melaleucae, and this appeared to correlate with different selective pressures on two isolated populations.            

  • Mushtaq Yousafzai added an answer in DOA:
    Can any one recommend me some recent papers and other material for DOA estimation for NULA?

    Any one could help me to recommend recent papers and other material ( books, thesis, etc) for DOA estimation for Non-uniform linear array. i need this data for writing proposal on this topic.

    Mushtaq Yousafzai

    surly i will go for it. thanks a million, 

  • prof V.S Muralidharan added an answer in Gluconates:
    Can any one comment on if zinc gluconate is a chelator?

    If the chemical bond between the zinc and gluconic acid is ionic, can we consider it a chelator? I will appreciate if anyone can recommend literature.

    Thank you

    prof V.S Muralidharan

    good eco friendly chelate - (GH) is the ligand

  • Min wu added an answer in Synaptosomes:
    How can I look at a presynaptic D2 (short?) receptor in striatum?

    Hi. Does somebody have an idea on how to quantify the presynaptic D2 receptor in mouse striatum? Should I prepare striatal synaptosomes and run western on them? Do good antibodies exist for D2 receptors? For mouse tissue? Does any antibody really select for D2 long form? Other ideas? Thank you!

    Min wu

    May try IHC with both DAT and D2 antibodies , then quantify D2 co-located with DAT if you have a good microscope.

  • Oleksandr Kucherak added an answer in Fluorescence:
    Is there any membrane-impermeable cell tracker (tracer) which shows fluorescence only inside the cell?

    I'm searching for a cell tracker/tracer which is non-fluorescent outside the cell and cannot cross cell membranes freely. Once the dye is brought inside the cell it should remain there and gain fluorescence.

    Has anyone worked with something like that?

    Thanks in advance

    Oleksandr Kucherak

    may be NR12S can work? it stains only membrane (outer layer can be switched off by dithionite upon spectroscopy/imaging)

  • Valentin Danci added an answer in Gravitational Field:
    Is the non locality of the gravitational field energy a serious problem for General Relativity (GRT)?



    "Although there is no room for such a thing in the energy–

    momentum tensor T, it is clear that there are situations where a ‘disembodied’

    gravitational energy is actually playing a physical role.

    Imagine  two massive bodies (planets, say). If they are close together (and we can

    suppose that they are instantaneously at rest relative to each other), then

    there will be a (negative) gravitational potential energy contribution which

    makes the total energy, and therefore the total mass, smaller than it would

    be if they are far apart.  Ignoring much tinier energy effects,

    such as distortions of each body’s shape due to the gravitational tidal field

    of the other, we see that the total contributions from the actual energy–

    momentum tensor T will be the same whether the two bodies are close

    together or far apart. Yet, the total mass/energy will differ in the two cases,

    and this difference would be attributed to the energy in the gravitational

    field itself (in fact a negative contribution, that is more sizeable when the

    bodies are close than when they are far apart)." 


    The same problem was also rised by Thirring, Kalman and Feynman in the FGT theory, they inserted the gravitational energy in the tensor equations...

    It is a problem of paramount importance which prevents the General relativity theory from describing any motion in which the hamiltonian is time dependent or rather in case of non isolated systems, or in case of non stationary interactions between different bodies.

    The attempt to model a free falling body in a gravitational field for GRT seems impossible.

    GRT has been tested  only for static or stationary systems where there is not a net exchange of energy (excluding gravitational radiation)

    Don't we need another GRAVITATIONAL THEORY which includes the results give by GRT in order to explain with a better accuracy the simple phenomenon like the free falling of a mass in a gravitational field?

    Valentin Danci

    Obviously you still can't read. I said "in a relativistic context, the application of LT".

    Can you read that part - "in a relativistic context"? Do you know what it means?

    Yes it's clear, Charles Francis (of Jesus College, Cambridge) either cannot read or doesn't know what "relativistic context" means. Or, likely both.

  • Leroy Jia added an answer in Turbidity:
    Is an MBR Effluent with no color possible ?

    I need some ​suggestion on ​MBR effluent ​for reuse ​potential. The ​effluent water ​meets the EPA ​reuse Standards ​with turbidity.

    Leroy Jia

    MBR can generate MF/UF process quality effluent, if applied properly, you should get  SS<1mg/L, turbidity<0.2NTU, I think MBR+RO would be enough for you.

  • Sylwia Macinska asked a question in Priming:
    What are the ways to measure the influence of affect on decision making process?

    I would like to know if there are any tasks, other than affective priming paradigm that can be used to measure the influence of affect heuristic on cognitive judgements.

  • Hediye Erdjument-Bromage added an answer in Proteomics:
    Is there a standard method for separating technical variability from biological variability?

    We have a proteomic dataset where many proteins have been identified in samples derived from two classes of samples with three biological replicates each. Each of these samples was analysed (injected into an LCMS instrument) twice, generating a technical duplicate (this means, that we have 12 LCMS results in total, six sets of duplicates). We have used a technique (SWATH) where we have essentially no missing values for any of the proteins.

    When playing with the data (e.g. making a x-y graph where two different replicates are compared to each other), it is clear that (as expected) technical noise is much lower than biological noise (differences in protein abundances between different sample sources).

    Can anybody advise me how this observation could be quantified? As we only have duplicates for each sample, we cannot work with standard errors when trying to capture technical variability. If we just take the difference of a value between technical duplicates, we neglect that we have duplicates for EACH sample. What does the average of the six differences tell us and how can this be related to the average of three means in each class?

    Hediye Erdjument-Bromage

    Hi Achim,

    Have you tried MaxQuant LFQ?

    You can merge the technical replicates in each of the biological replicates to have one experiment.  So, at the end of the day, you will be able to compare 6 sets of data that has, in each dataset, replicates merged..Most softwares have the "merge" function.  As stated above, since you have biological replicates, they are more valuable than technical replicates.

    Maybe another approach can be as follows:

    Set 1, biological replicate 1 (2 tech replicates merged) vs Set 2, biological replicate 1 (2 tech replicates merged)

    Set 1, biological replicate 2 (2 tech replicates merged) vs Set 2, biological replicate 2 (2 tech replicates merged)

    Set 1, biological replicate 3 (2 tech replicates merged) vs Set 2, biological replicate 3 (2 tech replicates merged).

    This way, you will be able to compare two sets with 3 biological replicates.



  • Prica Mbikou added an answer in Protein Phosphorylation:
    How do I quantify the phosphorylation relative to total protein on western blot?

    I am working on AKT phosphor and tot protein. I have blots with both proteins and need to quantify the phophoAKT band relatively to the total AKT band, both bands being detected by 2 different Ab.  When acquiring the signal (using a chemi geldoc system and a CCD camera, Alliance system) the pAKT band has a different threshold of saturation than the total AKT. For instance, if the saturation of pAKT band starts from 1.5sec of exposure, the total AKT band would start getting saturated at 0.5s. My question is this one: when doing the ration pAKT/totAKT, which exposure time should I pick for each band? should it be pAKT 1.4s/totAKT 0.4s (I picked 0.1s below the overexposure time to avoid using the threshold saturation value)? or should it be the same exposure time for both bands e.g. pAKT0.4s/TotAKT0.4s? I have noticed that depending of the exposure time, the value of the quantification vary.

    Thank you for your insights.


    Prica Mbikou

    Thanks a lot you all for your valuables input from which I learn new methodology of quantification! @ andreas, I will definitely try the phos-tag gel. @ Francoise, the high density immunoblotting methodology sound easy but yet very clever. Best wishes

  • Shivasankari Gomathinayagam asked a question in Antibody Production:
    Help with antibody production - know a "good" and cost economic company to help me with custom making my antibodies ?

    We have tried one company but we are not very convinced. So please comment with any options you might know or have had good experiences with. Our host will most likely be rabbit. I work in the US.

    Thank you.

  • Sheridan Clare Mayo added an answer in Neutron Physics:
    How do I calculate neutron attenuation coefficient?

    How to calculate or obtain neutron attenuation coefficient for any element at any given energy?

    Sheridan Clare Mayo

    Try this web page from NIST https://www.ncnr.nist.gov/instruments/bt1/neutron.html 

  • David L Morgan added an answer in Grounded Theory:
    What is the most appropriate qualitative approach?

    In my qualitative study I will ask ethnic patients regarding their health care preferences and needs so to manage their disease. Then,  I will ask them to validate a proposed patient-centred care model based on their preferences and needs. I read extensively, and not sure whether phenomenology would suit (given that patient perspective is sought) or would it have to be grounded theory given that I am developing a patient centered care model for a certain patient group? Thanks 

    David L Morgan

    Yes, grounded theory can be quite demanding. And yes, it certainly does rely on purposive sampling, as does nearly all qualitative research. Purposive sampling simply means that you select your participants to match your purposes, which in this case would be patients who can report on specific kinds of illness experiences

    GT typically goes beyond purposive sampling to do what it labels theoretical sampling. This means that as you develop your theory, you think about what kinds of people to interview next. Thus, the nature of your sample evolves as your theory evolves.

  • Ali Hasan added an answer in 3D:
    Is there public dataset for evaluating 3D segmentation?

    I implement 3D segmentation and I want to evaluate my algorithm, I am looking about public dataset if it is available



    Ali Hasan

    Dear Mr Ahmed

    I am so grateful

    I use Matlab to read the mha files but unfortunately the read images are in black and white not in grey scale, how can I use them to compare them with my result of segmentation



  • Sahar S Dalahmeh added an answer in Clotrimazole:
    Which types of IS standards can one use for the analysis of Omeprazole, Pyrimethnamine, Clotrimazole, and Lumefantrine?

    Which types of IS standards can one use for the analysis of Omeprazole, Pyrimethnamine, Clotrimazole, and Lumefantrine?

    Sahar S Dalahmeh

    Dear Samir, thanks for the hints. They are really helpful. I'll look att these characteristics and compare them with drugs I want to analyze.

  • Erkki J. Brändas added an answer in Graphene:
    Why the adiabatic Born–Oppenheimer approximation (BOA) is broken down in graphene?

    I want to know is the broken down of BOA in graphene has been solved or not yet,

    See the link


    what are the other cases where the BOA is also broken down in them and Why

    Erkki J. Brändas


    As being employed at a state university, most references should be available to you.

  • David Charles Wright-Carr added an answer in Neuroscience:
    What contemporary visual artists are applying principles from fields like neuroscience, neuroaesthetics, and visual perception?
    Scientific research has shed much light on how we see, and on how visual art resonates in our minds. I am interested in reading about contemporary visual artists who have applied this information in their creative processes.
    David Charles Wright-Carr


    Thank you for providing examples of your visual thinking and enactment (in the Varelian sense of the word).

  • Kelly Kirkley added an answer in Neuron Culture:
    Why are my primary rat neuronal cultures dying at around 14 days?

    We are plating primary hippocampal neurons from rats at post-natal day 0-2.  At plating 350,000 cells/mL with a total of 4 mls/plate.  We coat our plates with PDL and then with lignin.  At plating, the cells are placed in MEM + FBS + L-glutamine + Pen/Strep.  The day after plating they are switched to what we call neuron media containing Neurobasal A + B27 + Glutamax + FdUR + Uridine+ Pen/Strep.  We feed the plates every 3-4 days by removing 2 mls and replacing 2 mls of fresh neuron media.  The cells look great all up to the change right around 14 days.  After this change, like clockwork, the cells start dying the next day.  I make up the fresh media the day of changing and do not let it sit for more than 10 minutes in the waterbath.  Any suggestions why the cells do well for so long and then start dying at this last media change?  We are hoping to work with more mature neurons (day 14 or older) but so far have not been able to. 

    Kelly Kirkley

    The density is pretty thick considering we need neurons for western blot (1.4 million cells per 60mm plate..  I am unsure how a glial feeding layer would do if I need enough cells to obtain protein for western blot.  Would just placing glial conditioned medium be enough?  I did try feeding the cultures less and had success, but this did not work the second time (died after the 3rd feeding right before 2 weeks).  I think this next culture I will try not adding mitotic inhibitors to a plate and see how it fares.  

  • Erkki J. Brändas added an answer in Theoretical Physics:
    Is the concept of field the proper way to describe physical processes?

    What is a field? Everywhere around a 'source' of the field, if we put a 'test particle', then a 'force' will be applied to it, coming from the source.
    This definition has a critical drawback:

    • if you calculate, using volume integrals, the total energy of the field , then you will find it infinite. Is this acceptable?

    On the contrary, there exists the interaction from a distance view, where a force is applied to the test particle only when it is being present in the neighborhood of the source. So, we have not any kind of infinite energy here.
    Which approach do you believe that is correct and why? 

    Erkki J. Brändas

    Dear Jose,

    You are dead wrong! Quantum mechanics concerns the quantal nature of physical material systems. Mathematics is a succinct language for the formulation of natural laws utilizing the axioms of linear algebra. Thus quantum mechanics is a deductive fundamental physical theory that describes reality to an unsurpassed exactitude. 

  • John Sosa asked a question in Image Analysis:
    Does anyone have a need for powerful, yet intuitive image analysis software?

    On December 14th, 2015, we will release a free beta trial of MIPAR, a product we feel to be an extremely powerful 2D/3D image analysis software package. Its use of a 5-app, recipe-oriented architecture has enabled it to tackle segmentation problems few, if any, other packages could.

    If interested, please visit www.MIPAR.us to learn much more, sign up for the free trial, and/or submit a test image! Please let me know of any thoughts you might have.

    Click the box below to see one our latest solutions to the challenging segmentation of heat-affected zones (HAZs) from a weld-bead cross section...

    + 1 more attachment

  • HAYDER A. ABDULBARI added an answer in MEA:
    How to blend two different chemical fluids?

    I am working on blending of fluids like MEA, DEA and TEA.


    your question is not clear.... are you doing solutions?

  • Aimen Zeiny asked a question in Nanofluids:
    What is the scientific interpretation of light reflection?

    Why does light reflect from mirror-like surfaces? And is there a reflection of light when the light passes through a nanofluids? and Why?

  • Stam Nicolis added an answer in Convergence:
    How do I prevent premature convergence?


    I used ABC algorithm.I know that is good at exploration but poor at exploitation. so I used a method to improve its convergence but it gets stuck in premature convergence ?! which techniques are useful to prevent this problem. and How Can I create a appropriate balance between appropriate and exploration.


    Stam Nicolis

    What does ``premature convergence'' mean? If it's a local extremum, simulated annealing or tabu search can be used, for example.

  • Marco Fedi 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.

    Marco Fedi

    I answer about the Shapiro effect. Stefano said above that this effect demonstrates that the speed of light is not constant. We don't have to misunderstand this elementary effect of General relativity. The Shapiro effect simply means that - due to the curvature of spacetime (for its part due to the presence of a celestial body, like the Sun) - the rays of light have to travel "a longer distance" than the supposed straight line we would imagine. This means that - of course - light will need more time to reach the destination (respect to what calculated for a "flat" spacetime), being reflected and coming back to the point of emission. It's standard physics. The relativistic aspect is the unexpected curvature of space, which extends the path of the rays. The Shapiro effect is indeed an evidence for general relativity's space topology. But the velocity of light remains constant. Indeed "c" is one of the three fundamental constants of physics (G, c, h). 

  • Carlos Eduardo Maldonado added an answer in Validation:
    Would you agree that a «How...?» question is asking for a scientific explanation, whereas a «Why...?» question asks for a phylosophical answer?

    I wonder...

    Just the other day, as I told this to my students, I stopped for a while, and then I added. «...But isn't Phylosophy a Science ???»

    I should like to know your approach to this. 

    Isn't Phylosophy of Sciences a valid and valuable field of the scientific matter?

    Carlos Eduardo Maldonado

    Dear Maria, you are right if you look at the question from a classical, i.e. ancient point of view. However, throughout history things have extremely changed and that is not the case any longer. Neither for philosophy, nor for science.

    Besides, there was a time when philosophy was considered, to tome extent, a science. For the Aristotelian tradition, for instance, or also for the Wien school. Nowadays no serious philosopher is truly worried about the fact that philosophy be considered a science, or not. The entire framework has radically changed, too.

  • Amin Hodaei added an answer in Water Vapor:
    How can we plot 2D (P-T) phase diagram of water by projection of the intersections of the temperature-pressure-chemical potential planes?

    What are the equations of the chemical potentials of ice, water and vapor according to the changes of temperature and pressure?

    Amin Hodaei

    Dear Mr. De Vries, thank you so much for your answer. Actually, the thing that I am looking for is to know the equations of the lines that separate the liquid, solid and vapor phases regions (with respect to the changes in temperature and pressure). would you please help me know how I can find these lines' equations?


  • Amir Abolhassani asked a question in Ordination:
    How can I weigh observations differently that were provided for a time horizon?

    I have 623 observations with one continuous dependent variable and 13 independent variables (continuous, categorical, and ordinal), defined based on researcher experience and literature review. I considered planning to do several regression analysis to estimate the dependent variable and study the predictive factors (if they are positive, negative, and their magnitude) on it. Data are provided for 10 years. Since the latest observations are more important, I’m interested in using weighted observations. How can I approach this problem and validate my approach? Thank you.

  • Fatima Alarcon asked a question in Extraction:

    Good afternoon: Please someone help me explaining that the FULLFAT in the extraction of proteins and so serves?