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ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.

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  • Stephen D. Koch added an answer in Plant Identification:
    Please identify this species?

    Please help me in identification of this species. 

    Regards

    Stephen D. Koch · Colegio de Postgraduados

    Cuscuta

  • Jafar Bagheri added an answer in Open Source Scientific Software :
    combination of two solvers in openfoam
    Dear Friends,
    I need to combine two solvers in openfoam but i dont know how start.
    please help me.
    saeed
    Jafar Bagheri · Islamic Azad University,Eslamabad-e Gharb Branch,Iran

    Dear Saeed

    you can modify a solver and add new variable or code to it. for more details please go to:

    http://www.tfd.chalmers.se/~hani/kurser/OS_CFD_2012/MostafaPayandeh/ViscosityModel%20in%20openFoam%20v2.pdf

    regards

    Jafar

  • Shuichi Shinmura added an answer in SPSS:
    R Squared Value is high (about 0.70), however, the p value for all my independent value is over 0.05. How could this happen?

    In my data analysis with SPSS, my model's R Squared Value is high (about 0.70), However, the p value for all my independent value is over 0.05. How could this happen?

    Shuichi Shinmura · Seikei University

    Vera, you points out good point.

    Bu, about collinearity, I have many experiance.

    I developed how to detect collinearity and delete several variables.

    See my paper about CPD.

    Next spring, I upload this matters. Below is answer relate to other question.

    ********************

    Collinearities

    I read your question one week ago. I was writing a paper related to your questions. I finish to wright a paper and spend many hours to look for your questions again. RG should offer the function to find by key-word.  

    Below is the conclusion. This paper will be upload next March. But, you can download about CPD data after 2014. I compare three approach such to analyze the original data, analyze after PCA (approach 1) and delete some variables relate to collinearity (approach 2). The best result is approach 2 and the worst one is approach 1.

    **********************************************************

    5.       Conclusion

    In this research, we discuss the new method and model selection procedure of the discriminant analysis using the CPD data with collinearities. Our examination tells us that the second approach (to exclude the variables relate to collinearities) is the best, and the first approach (bundle of PCA and regression analysis) is the worst. The common consensus that we had better regressed the data with collinearity using new variables by PCA may be wrong. We must examine this fact in other cases if we can access other data with collinearities.

    **************************************:

  • D. V. Grigoriev added an answer in Mosasaurs:
    How do I distinguish mosasaurian teeth from crocodilian?

    Mosasaurs have different types of teeth (see attached figure from Bardet et. al, 2014.)

    But so do crocodiles...So, How to distinguish  in general mosasaurian teeth from crocodilian? (for example the first picture shows Crocodyliformes tooth, and the second Prognathodon sp. (Mosasauridae))

    D. V. Grigoriev · Saint Petersburg State University

    Yeah, they have!

  • Xin Wang asked a question in Flow Cytometry:
    How many colon tissue needed for T cell gating by flow cytometry?

    Hi,

       Here I want to analyze the T cell (from mice colon tissue), including Th1, Th17 in flow cytometry, Considering the cells number, what's the length of the colon do I need for cell collection for flow cytometry? if I only use distal colon tissue for flow cytometry, will the cells enough for T cell or macrophage analysis or detection in flow cytometry? Many thanks!

  • Alexander J. Babchin added an answer in Zeta Potential:
    Do you know of any microparticle with zero ζ potential?

    I am looking for a particle that has zero ζ potential, so that the particle can be a "perfect" tracer for fluid flow without experiencing any additional phoretic effects. Is there any particles that possess zero ζ potential? Thanks.

    Alexander J. Babchin · Alberta Research Council (ARC)

    Most of particles have isoelectric point while dispersion phase  is titrated.

  • Akash Kannegulla added an answer in Hydroquinones:
    How can I minimize aggregation of gold nanoparticles during functionalization with APTES?

    I've synthesized large gold nanoparticles (~100 nm) using the Perrault method with citrate and hydroquinone.

    I've also coated these particles with monodisperse silica using APTES and sodium silicate. 

    I now want to further modify the surface of the silica with APTES in order to attach a porphyrin. I've been centrifuging the coated particles to get rid of excess silica and then resuspending with APTES in ethanol. However, this seems to result in aggregation over the course of an hour, where all the color fades from the solution. 

    Has anyone encountered this before, and/or would they happen to have any tips?

    Thanks! 

    Akash Kannegulla · Oregon State University

    So you coated 2-4 nm thickness in a day and by just adding ethanol, you did not face any aggregation issue? 

  • Anuschka van ´t Hooft added an answer in Endangered Languages:
    What strategy do you advise to use for processing endangered languages?

    Some strategies to help preserving and revitalizing endangered languages have been proposed, do you advise any?

    Anuschka van ´t Hooft · Universidad Autónoma de San Luis Potosí

    Dear Fadoua:

    There was a similar question last February from Dr. Jones Michael Jaja, who wondered if there were developmental steps to follow in order to revive a nearly extinct language. You may find some answers in that thread that might help you. 

    Your question is more general, as it concerns all languages that are more or less endangered, so I think the first step would be to determine the situation of the particular language you want to work with, as each situation calls for a different approach. When you know about the degree of endangerment, the materials available in the language, the profile of the speakers, status, among others, you can see whether it would be best to start with language description or whether to do a language documention project, whether to implement language nests, to focus on educational materials, language learning, or policy, or do a mixture, etc.

  • Simon Anthony Jackson added an answer in Multiple Regression:
    In multiple regression, if the constant is not significant but the other variables are (in the coefficient table), what does this mean?

    I know it means that the constant will not significantly differ from zero when other variables are zero, but does this mean that my model is not reliable and I should not include it in my results? Any sources explaining this is greatly appreciated.

    Simon Anthony Jackson · University of Sydney

    As you pointed out, the result means that when all predictor variables = 0, then the constant does not differ significantly from zero.

    In line with Tom and Jim's comments, in most research contexts, the intercept is uninformative, not reported (significantly different from zero or not) and (to add caution to Shuichi's advice) not constrained. Put simply - in general, don't worry about the intercept and don't report it.

    Here's a typical example for my area: I regress university student Grades on IQ and age. Grades are on a scale of 0 to 100, IQ is scaled with mean = 100, SD = 15, age ranges from 18 up. What is the intercept: When IQ and age BOTH equal 0, it's the predicted grade. But what is an IQ of 0? What is an age of 0? Neither of these exist in the data, nor do they make sense. Thus, the intercept is a meaningless value and I will ignore it.

    Only reason you would care is if you have a reason to consider the case of all your predictors being zero. This doesn't happen very often. If you think you might, then please give us more details about your variables.

    As for references, any text book covering regression should cover this issue. I've attached links to some good ones.

  • Ernesto Peña added an answer in Imagery:
    Does anyone know where I can find studies on the value of using art or photography in messaging to increase engagement and message retention?

    I'm a designer and art director working in public health. I'm often asked to support my contention that art increases engagement and retention. While I feel confident in my belief that it does, it would be helpful to be able to back it up with a study or two. I'd also like to learn more about how to select and test imagery for specific audiences.

    Ernesto Peña · University of British Columbia - Vancouver

    You should take a look at topics such as visual rhetoric. I am guessing that you are interested in a marketing perspective, this might be helpful as a starting point: http://blog.hubspot.com/blog/tabid/6307/bid/33800/Photos-on-Facebook-Generate-53-More-Likes-Than-the-Average-Post-NEW-DATA.aspx

  • Tausif Alam added an answer in Adipocytes:
    Is GLUT4 expressed in the liver cells?

    What I know GLUT4 expressed in adipocytes, skeletal and cardiac muscles but not in the liver, but I found in paper they said it is expressed in the liver? Perhaps I did not understand the point or I am wrong.

    Tausif Alam · University of Wisconsin–Madison

    Vincent, was your observation based on measurements in the whole tissue homogenates or was it via techniques such as immunocytochemistry or in-situ hybridization where one can ascertain that the presence of Glut4 corresponds to hepatocytes?

  • Khalid Dakhsi added an answer in Alumina:
    How do I smooth a titanium surface by polishing?

    Dear Colleagues,

    We are trying to polish Ti surface and used 320, 400, 600, 800, 1200, 1500 and 2000 grit SiC abrasive papers. 

     I have attached the SEM image, post polishing. The surface is still not smooth with artifacts (I guess abrasives) embedded.

    Kindly suggest if need to further polish using diamond, colloidal silica and alumina suspension in order to achieve smooth and minimum rough titanium surfaces.

    In literature, some authors have achieved mirror surfaces just by SiC papers. 

    Thank you in advance,

    Khalid Dakhsi · Université Ibn Tofail

    try 400, 600, 800 , and 1200 , 1500 use colloidal silica and alumina suspension, but take (low speed) , at the end, you have to rinse surface.

    in SEM micrograph attached, you have to phases of metal. and it's not very bad for analysis

  • Aldo José Fontes-Pereira added an answer in Porous Materials:
    How do I model fractures in highly porous materials?

    Any recommendations about this topic are highly appreciated!

    Thanks!

    Aldo José Fontes-Pereira · Federal University of Rio de Janeiro

     Dear Mohamed Ramy El-Maarry

    Please look at the articles below:
    https://www.researchgate.net/publication/269097674_ULTRASOUND_PROPAGATION_IN_FRACTURES_WITH_INTRAMEDULLARY_NAILING

    https://www.researchgate.net/publication/236664175_Computational_simulations_of_time_of_flight_and_attenuation_of_first_arriving_signal_from_healing_process_of_diaphyseal_femur_fractures

    https://www.researchgate.net/publication/259878491_The_effect_of_low-intensity_therapeutic_ultrasound_in_induced_fracture_of_rat_tibiae

    Regards,

  • Abhilash Harpale asked a question in Lammps:
    What are the Dreiding force field parameters for Graphene ?

    I am trying to use the DREIDING bonded force field for modelling graphene using lammps. I use atom type C_R for C atoms in graphene, but I am not able to figure out what bond_coeff, angle_coeff, dihedral_coeff and improper_coeff parameters to use. 

  • Armin Hallmann added an answer in Aflatoxin:
    Is it possible to extract aflatoxins without methanol?

    I am working on extraction of aflatoxin from sorghum grains and our lab has currently run out of methanol. Is there any other method to extract aflatoxin using water or any other polar solvent?

    Armin Hallmann · Bielefeld University

    Water alone is not suitable to extract aflatoxins. However, there are suiitable alternatives without methanol.

    Alternative solvent mixtures for extraction of aflatoxins are:

    • acetonitrile/water (84 : 16, v/v)
    • acetonitrile/water (90 : 10, v/v)
    • chloroform/water (30 : 1, v/v)
    • chloroform (pure)
    • acetone/water (85 : 15, v/v)
    • acetone/water (90 : 10, v/v)
    • acetone/hexane/water  (54 : 44 : 2, w/w/w)

    You should take into account that solvents like acetone or acetonitrile are more “aggressive” than methanol and you have to use appropriate/resistant laboratory material.

  • Simon Cleveland added an answer in Learning Management Systems:
    Which is the best IS theory to evaluate the effectiveness of a Learning Management System?

    I would like to know which is the best IS theory to evaluate the effectiveness of Blackboard as a supporting tool for students.

    Simon Cleveland · Brandeis University

    Dear Sizwe,

    In addition to Michael's recommendation, try the following two sources for other ideas:

    http://sighci.org/Research/ijhcs_03/Yi.pdf

    http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.231.8887&rep=rep1&type=pdf

    Good luck,

    Simon Cleveland

  • Raveendra Nath Yasarapu added an answer in Climate Change:
    Is it time we shift emphasis from technological solutions to climate change & focus on the 'Human Dimension'?

    Isn't the obvious solution and elephant-in-the-room 'BETTER HUMAN BEINGS'? Shouldn't the focus be on better human beings rather than better technology? Is it not obvious that nature can heal itself, if only left alone, and it is we humans who need regulation? Many natural parks managers do just that; seal off the area from human interference to let nature heal and recover. It is classified as 'Strict Nature Reserve"by IUCN. Complacency and inaction are not advocated here, as many have misunderstood, but the shifting of focus from technology to the human being. As technology is no match for human greed, isn't introspection & restraining ourselves more relevant than developing more technology, which caused the mess in the first place, by making it easy for a few to consume more? Since technology is only a short term quick fix which fails after a short time, isn't the real problem our addiction to material consumption & our lack of understanding about human nature? Isn't developing more technology sustaining the addiction instead of correcting it, leading to more complex problems later on, needing more complex technological quick fixes like higher drug dosages, more ground troops & equipment, (along with their debilitating side effects) in the future? Isn't this the vicious addiction circle we are trapped in? As researchers, do we merely buy more time with technology OR go to the very root of the problem, the human being?

    A lot of hue and cry is made about climate change and the environment in general. Public and private money is poured into research to study its effects on the environment, sustainability etc. Should we study nature or ourselves?

    " Our studies must begin with our selves and not with the heavens. "-Ouspensky

    Human activities have been found to have a direct correlation to climate change and its impact on the environment(I=P x A x T, the Ehrlich and Holdren equation), in spite of what some complacent sections say to protect their own self interests.

    We hardly know about Human nature. We can scarcely predict human behavior. We need to find out why we think like we do and why we do what we do and why, in spite of all knowledge and wisdom, consume more than what we need, in the form of addictions to consumption and imbalance not only ourselves but also the family, society and environment around us..
    Humanity is directly responsible for all the unnatural imbalances occurring on the planet. Yet we refuse to take responsibility and instead focus on climate change, or fool the public exchequer with a 'breakthrough in renewable energy just around the corner'. We scarcely know what drives human beings. If we had known, all the imbalances around us would have had solutions by now, given the amount of money plowed into finding such solutions. Are we blindly groping in the dark of climate change because we don't know the answers to our own nature?
    Is it not high time we focus on what makes us human, correct our consumptive behavior and leave nature to take care of climate change? Why focus effort on 'externals' when the problem is 'internal'- 'me'?
    Aren't we addicts denying our addiction and blaming everything else but ourselves?

    " We are what we Think.

    All that we are arises with our thoughts.

    With our thoughts, we make the world." - Buddha 

    IMHO, We don't need to save the World. It is enough if we save ourselves from ourselves. The need of the hour is not vain glorious interventions, but self-restraint and self-correction!

    The Mind is the Final frontier.

    Raveendra Nath Yasarapu · Technische Universität München

    Dear Antonio,

    Great to hear that there are no radioactive by-products. Being 'off the electric grid' sounds too good. Will current energy market leaders allow that to fructify?

    Agree with you on the "experimental side and the development side". Pressing ahead with the development while watching out for possible consequences is a good plan of action. If it is carried out with good plain motives, success is sure. 

    Regards

  • Simon Cleveland added an answer in Communication Engineering:
    Can anyone recommend papers or books on the NonLinearities in Resistive String DAC's arising due to gradient mismatches, resistor mismatches?

    Gradient related Mismatches, Resistor & Capacitor Mismatches resulting in Non Linearities in Resistive String DAC's to do an Efficient Layout for an 8bit multi level String RDAC segmented into 3(MSB) + 5(LSB) with reference voltages of Vref(MSB)=0.75V, Vref(LSB)= 100mV.

    Simon Cleveland · Brandeis University

    Dear Prasad,

    Try the following books for additional ideas:

    https://books.google.com/books?id=pTqI98FJYlYC&printsec=frontcover&dq=Resistive+String+Gradient+Capacitor+Mismatches+String+RDAC&hl=en&sa=X&ved=0CCUQ6AEwAWoVChMIhdX79-HMxwIVzjweCh1fbAbx#v=onepage&q&f=false

    https://books.google.com/books?id=w2jkplqMig0C&printsec=frontcover&dq=Resistive+String+Gradient+Capacitor+Mismatches+String+RDAC&hl=en&sa=X&ved=0CDkQ6AEwBGoVChMIhdX79-HMxwIVzjweCh1fbAbx#v=onepage&q&f=false

    https://books.google.com/books?id=v39JAQAAMAAJ&q=NonLinearities+Resistive+String+Gradient+related+Mismatches&dq=NonLinearities+Resistive+String+Gradient+related+Mismatches&hl=en&sa=X&ved=0CB0Q6AEwAGoVChMIp-Wa1eHMxwIVyyQeCh0clQWI

    Good luck,

    Simon Cleveland

  • Dr. Sarhan Soliman asked a question in SPSS:
    How to Analyze the trend of the time series for variable some its volums were negative by spss?

    How to Analyze the trend of the time series variable some its volums were negative by spss program? example balance of trade between any two countries.

  • Paul Chaney added an answer in Science Communication:
    Does anyone know case studies on impacts of Internet on science communication?

    Hypothesis is that Internet is turning science communication upside down. I am looking for additional evidence from around the world.

    Paul Chaney · Cardiff University

    Dear Laxmi Pant,

    I hope the following references may be of assistance.

    Kind regards,

    Paul Chaney

    Eisend, M. (2002) The Internet as a new medium for the sciences? The effects of Internet use on traditional scientific communication media among social scientists in Germany, Online Information Review, Volume 26, Number 5, 2002, pp. 307-317. http://dx.doi.org/10.1108/14684520210447877

    O'Connor, M. (2006) Building knowledge partnerships with ICT?: Social and technological conditions of conviviality, Interfaces between Science and Society, Volume 1, pp. 297-325. http://dx.doi.org/10.9774/GLEAF.978-1-909493-67-4_19

    Thorsen, Einar (2013) Blogging on the ice: Connecting audiences with climate-change sciences, International Journal of Media & Cultural Politics, Volume 9, Number 1, 1 March 2013, pp. 87-101. http://dx.doi.org/10.1386/macp.9.1.87_1

    D Treise, K Walsh-Childers, MF Weigold (2003) Cultivating the science internet audience impact of brand and domain on source credibility for science information, http://scx.sagepub.com/content/24/3/309.short

    KY Yang, JS Heh - Journal of Science Education and Technology (2007) The impact of internet virtual physics laboratory instruction on the achievement in physics, science process skills and computer attitudes of 10th-grade students,  http://link.springer.com/article/10.1007/s10956-007-9062-6

    ur Rehman, Sajjad; Ramzy, Vivian (2004) Internet use by health professionals at the Health Sciences Centre of Kuwait University, Online Information Review, Volume 28, Number 1, 2004, pp. 53-60 http://dx.doi.org/10.1108/14684520410522457

    Rogers, Laurence; Twidle, John (2013) A pedagogical framework for developing innovative science teachers with ICT, Research in Science & Technological Education, Volume 31, Number 3, 1 November 2013, pp. 227-251. http://dx.doi.org/10.1080/02635143.2013.833900

    Paige Miller, B.; Sooryamoorthy, R.; Anderson, Meredith; Palackal, Antony; Shrum, Wesley (2006) Gender and Science in Developing Areas: Has the Internet Reduced Inequality? Social Science Quarterly, Volume 87, Number 3, September 2006, pp. 679-689. http://dx.doi.org/10.1111/j.1540-6237.2006.00403.x

    Lock, Andrew (2010) Information and communication technology and marketing science: a long term perspective on evolving consumer behaviour, Journal of Customer Behaviour, Volume 9, Number 1, Spring 2010, pp. 77-83. http://dx.doi.org/10.1362/147539210X497639

  • Simon Cleveland added an answer in Management Control:
    What are the management control mechanisms for effectively and efficiently managing budgets in an organization?

    What are the management control mechanisms for effectively and efficiently managing budgets in an organization? 

    Simon Cleveland · Brandeis University

    Dear Gedion,

    Take a look at the following sources for additional ideas. You may need to search for budget performance indicators in order to uncover various control mechanisms.

    http://iiste.org/Journals/index.php/EJBM/article/download/4545/4626

    https://www.researchgate.net/profile/Wouter_Van_Dooren/publication/259925122_HOW_TO_MEASURE_PUBLIC_ADMINISTRATION_PERFORMANCE_A_Conceptual_Model_with_Applications_for_Budgeting_Human_Resources_Management_and_Open_Government/links/00b7d53c8cd6eed5db000000.pdf

    http://library.wagner.edu/SI_Reports/PresentProblems2004.pdf

    Good luck,

    Simon Cleveland

  • Julie E Niemela added an answer in Mutation:
    Is there a way to identify hemizygous positions in WES?

    I'm analysing WES of ovarian cancer and besides common heterozygous BRCA1/2 SNPs, there are a few homozygous BRCA1/2 variances. Given that ovarian cancer patients have 1 germline mutation (let's stay with the example of BRCA1/2) and receive a "2nd hit" - a somatic mutation, I would therefore look for different het mutations in my WES data (because it is rather unlikely of the 2nd mutation to appear exact at the same position). Thus, what are those hom calls, additional mutations the tumor has acquired?

    An example of a hom call: Read Depth 92. Alt Read Depth 6. Allelic Depth 6,85. Dupl of A leading to fs and ter. Not reported in dbSNP, Cosmic, Clinvar. I'm working with Basespace and use the Illunmina Variant Studio. There is the option to filter het/hom/hemi but this is not helping me. I thus think this is a hemizygous variant (germline) and the other allel became somatically deleted. Is that possible or am I making a mistake? Any suggestions are welcome!

    Julie E Niemela · National Institutes of Health

    I am also going to check out CEQer - thanks Rocco!

  • Matheus Bertanha asked a question in ImageJ:
    Fractal analysis and ImageJ for sclerotherapy?

    We have a research project in which we perform scerotherapy in small veins. We have photographs (HD) of the treated area, both pre-treatment and 60 day post-treatment. We would like to apply fractal analysis with ImageJ to get an automatic percentage of how much the treatment improved the general area.

    does anyone have a tutorial on how to proceed?

    Thank you very much!

    ps. we have some photographs if someone choose to help us!

  • Ahmad Rozelan Yunus asked a question in HRD:
    Anyone in HRD or Counseling Psychology know any real databases of various type of workers personality traits?

    I know well MBTI personality tool. If someone has experience applying this tool in activities of Employee Assistance Program, that know some of existing data of various working type or organization such as white collar and blue collar workers?

  • Eric Lord added an answer in Special Relativity:
    Is there a solid proof of non existence of the absolute reference frame or no one has found the proof yet?

    Special Relativity tells us there is no privileged frame but these are just words in Einstein's seminal paper. In Einstein System the assumption of equal speeds of light in both direction cleverly relieves us from the necessity of having one, but as I see it it is just a convenience. But where is the proof?

    I think Galilean view is more likely to lead to the conclusion of non existence the absolute frame than Einstein's.

    Eric Lord · Indian Institute of Science

    Dear Azzam ~

     “I think you understood there is no any violation between my theory and EM and because of that you kept silent. If you found anything wrong, then you would not keep silent.”

     I kept silent because I’m thoroughly bored with the discussion ( ;

     But since you are so persistent I’ll show you something obvious that you should have seen for yourself:

    As is well-known, Maxwell’s theory implies that the path of a light ray satisfies

    (dx/dt)2 + (dy/dt)2 + (dz/dt)2 = c2

    (meaning, of course, that the speed of light is c.)

    We can write this as c2dt2 − dx2 − dy2 − dz2 = 0.

    As is easily verified, this is invariant when we apply the Lorentz transformation

    x′ = γ(x − vt), y′ = y, z′ = z, t′= γ(t − vx/c2) [that is, we get c2dt′2 − dx′2 − dy′2 − dz′2 = 0.]

    It’s obviously not invariant if we have  y′ = Ry, z′ = Rz. That is, the transformation law suggested by you is not compatible with Maxwell’s electromagnetic theory.

  • Khalid Dakhsi added an answer in Engineering Physics:
    Can there be a deconvoluted peak inside a deconvoluted peak?

    Have attached one example as well :

    http://www.google.co.in/imgres?imgurl=http://cdn.iopscience.com/images/1367-2630/7/1/107/Full/nj192173fig1.jpg&imgrefurl=http://iopscience.iop.org/1367-2630/7/1/107/fulltext/&h=632&w=434&tbnid=qs2wqml_GdJryM:&docid=ChbEre-680rTSM&ei=C9XdVfbTEcS30AS6z6eICg&tbm=isch&ved=0CAQQMygBMAE4ZGoVChMItoWuoILHxwIVxBuUCh265wmh

    Khalid Dakhsi · Université Ibn Tofail

    yes if  we know our compound list we can decompose a peak to overlap peaks. 

  • Lars Björndahl added an answer in Fertility:
    Are the Kruger criteria valid in males who aren't seeking fertility treatment?

    The Kruger criteria were developed for IVF, but an older classification system exists. Does anyone have a paper or data comparing the two?

    Lars Björndahl · Karolinska Institutet

    I agree with Carles that what we see in fixed and stained spermatozoa in smears is not identical with the live spermatozoa. On the other hand: without staining the contrast is too low to allow observations of any details of the spermatozoa.

    It is a misconception to say that spermatozoa fulfilling the Tygerberg strict criteria are "absolutely healthy". It has been stated that the criteria describe the morphology that is typical for sperm that can reach the site of fertilization (passing cervical mucus and binding to the zona pellucida). But this does not mean that the spermatozoa with this morphology always are able to fertilize the ovum and contribute to a normal embryonic and fetal development into a healthy child.

    I would also use the metafore of a car factory. The morphology assessment according to Tygerberg strict criteria tells about scratches and dents on cars delivered - and the percentage "typical" objects has a predictive value for a proper function of the car, but it does not tell if all cars with this appearance actually work properly. Still the measure has important information about how well the factory is working - many cars with many scratches and dents come from a factory that does not work well.

    So human sperm morphology should not only be seen as a tool to chose ART treatment modality - fundamentally it should be a tool to disclose problems in the patient - the man!

  • M. Kechida asked a question in Corneal Ulcer:
    What is your therapeutic attitude towards corneal ulcer in patients with rheumatoid polyarthritis who are sufficiently controled with methotrexate?

    Do you prescribe corticotherapy and change methotrexate treatment even if there are no articular signs of activity?