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  • Electronics engineers! what is your criteria for safe operating temperatures of boards & chips?

    which is most important to a nice design? eliminating hot spots, reducing overall temperature gradient or average temperature on a board?? Is ,for example, using two heat sources in vicinity of each other against any rules (.. of thumb)? 

    Farhad Falakzaadeh · Shiraz University of Technology

    Thank you all guys, comments full of helpful information..

    Dear @Amipara Manilal, I like to know more about  this " proper arrangement" you've mentioned, I mean, if we had no barriers we would wrap diamond sheets round around a die generating heat! But having materials with high & low thermal conductivity how would you "Arrange" them, In what order, for the "Ultimate=Optimum=Lowest temperature possible" design??  Plus, How would you know your arrangement is the best possible!

    you can check out my attachment here

  • Looking for a quasirevers. system of solution resident species that works at HMDE, any suggestions?

    not ferrocyanates or ferrocene-derivatives, too fast electron transfer rate

    Dariusz Guziejewski · University of Lodz

    haven't, will do, thanks

  • Elena Evderidou asked a question in Child Behavior:
    Hello, I would like to ask you how could I find the "child behavior checklist" adjusted in greek and the "Testbatterie zur Aufmerksamkeitsprüfung" ?

    Could anyone send me a link or an archive with the the above mentioned tests? I want to assess  children' with SLI attention and I have not found an instrument yet. 

  • Carmen Wrede added an answer in Workplace:
    Do people in workplaces speak another sociolect than at home?

    Open discussion. I would be pleased if you add any studies.

    Carmen Wrede · FernUniversität in Hagen

    "the problem is that I do not see a solution"

    Me neither. I am not even able to grasp in mind where exactly a 'mistake' could occur. Maybe when it comes to intentions and aims. If I asked anyone for example about their communication skills... what exactly do I then know about them? Maybe that a person is talkactive or able to express in a certain way. But doesn't social competence implicate the idea one will use his/her skills for the better which should be (calling it social) a little bit more than use it for the 'good' reason to magnify once own wealth or power? If I am measuring a skill which can be used either social or antisocial... doesn't make sense to call it 'social' only to ennoble somebody and at least empower them without knowing they are really social.

  • Larisa Gofman asked a question in BacMam:
    Anyone use pCMV-dest kit bacmam system to generate bacmam vector? Anyone have a protocol on how to purify the bacmam after you obtain the P2 stock?

    The pCMV-dest kit from Invitrogen (life tech) is used to obtain bacmam particles. However the kit only provides guidance to the P2 stock from the insect cells that release the baculovirus, and then they stop. Does anyone know how to purify the P2 stock, I've read butyrate with spinning, but then also some people say ultracentrifigation is bad because you lose a lot of the vector. Does anyone have a protocol they use on how to purify this?Ask

  • Has anyone conducted research on the far-learning transfer of international students' skills and knowledge on return to their home countries?

    The U.S. leads the world in accommodating the largest number of international students on their campuses. But, is there any research to show how well these students are able to apply their skills and knowledge to their local environments on return to their home countries?

    Debra Sharon Ferdinand · The University of the West Indies, Trinidad and Tobago

    Thanks much Tom!

  • William Corulla added an answer in Child Abuse:
    What are the psychologic characteristics of physical child-abuse perpetrators?

    What should be measured in a forensic eviroment? What instruments are suggested to be used?


    William Corulla · Personality and Temperament Research Center

    It seems to me that this question is asking for a profile of what a child physical abuser would be. Is there such a psychological profile? I don't thing that there is. The are personality inventories that can be used to see if abusers fit a specific personality such a NEO Personality Questionnaire. This can show a propensity towards antagonism , cruelness and so on. I think however that whatever psychometric testing is used extensive historical interviews must be used. This  series of interviews could tell if the patient has been treated is much the same way, if he or she has been bullied and the development of various patterns of behaviour. Most importantly is that we can't only rely on these  we must ask questions as to why the patient behaves the way they do. An inventory and most general interviews will get us almost there but the individual differences between different abusers is also needed and must be assessed. The low stimulus environment in secure conditions may allow for the on going assessment of the abuser.

  • Why electromagnetic field propagates via void vacuum?

    Water wave propagates via the water. Sound wave propagates via matters in solid, liquid or gas states. It is pretty logical.

    "Electromagnetic field propagates via void vacuum" is commonly accepted. In this case, void vacuum is media for light. If vacuum is true void, why it can be a media for carrying electromagnetic wave? Can you provide a logical answer?

    Zhiliang Cao · Shanghai Jiao Tong University

    Anyone has atomic clock? I need to perform an experiment. 

  • Daniel M Cohen added an answer in Multiplication:
    What is the optimum conceentration of DNA template for PCR reaction to amplify target gene?

    i have used earlier in takara mister mix for amplification to amplify target gene and gene size is 2415 bp. but now i have been using different enzyme for amplification and also same cyclic condition. i got multiple band whereas target band also very thin.what is the reason for this multiple band? What is the optimum conceentration of DNA template for PCR reaction to amplify target gene?

    Daniel M Cohen · University of Pennsylvania

    1-10ng of template in a 50uL reaction is fairly standard. More is not good. Although amplification can lower starting amounts is feasible, it is not recommended for cloning as you increase the likelihood of PCR errors with more extensive amplification.

    Different enzymes work in different reaction buffers that can affect the stringency of your oligo hybridization, especially due to changes in magnesium chloride concentration. It is not uncommon to see different PCR banding patterns and specificity of amplification using different polymerases. For cloning a larger cDNA (>2kb), you had best stick with a high fidelity enzyme (Phusion, Pfx, Pfu Turbo, etc).

  • Could anyone please give some tips related to how to write the lab view program for the measurement of Hall mobility and resistivity?

    Do anyone know about how to do looping between Keithley 6220 current source and Fluke 8846A multimeter.


    Could anyone please give some tips related to how to write the labview program for the measurement of Hall mobility and resistivity by using Keithley 6220.

  • Aroon Shenoy added an answer in Thermoplastic:
    Is there any thermoplastic polymer which requires higher processing temperature (250 C~290 C).?

    Currently I'm using PMMA, PVDF to make flat substrate. But I need a thermoplastic polymer which can be molded thermoplastically within the temperature range of 250~290 C. 

    Aroon Shenoy · SAICO

    Table 1.5 in the book A. V. Shenoy and D. R. Saini, Thermoplastic Melt Rheology and Processing, Marcel Dekker Inc., New York (1996) gives Information on Selected Homopolymers (LDPE, HDPE, PP, PS, PMMA, POM, PA, PET, PC, PVDF, PPO, PPS, PES, PAS, PEEK, PEI, PAr, PVC), and gives the Glass Transition Temperature Tg, Melting Temperature Tm, Highest Processing Temperature Tp and Degradation Temperature Td.  The choice of the thermoplastic polymer which requires higher processing temperature (250oC~290oC) can be made by picking the one that fits in this range based on its Melting Temperature Tm and the Highest Processing Temperature Tp.  A polyamide, a polyester or a poly(vinylidene fluoride) would probably fall closest to these requirements.

  • Dou you have published journal about Curriculum development, psychology and philosophy of education

    Content analysis is one of the methodologies in research

    Mikko Ketovuori · University of Turku

    Look my thesis, it is at least about the philosophy of education...

  • Lewis Alan Opler added an answer in Psychosis:
    Can someone commit a crime because of their schizophrenia?

    Until recently, I thought the answer to this question was obvious, but I am gradually becoming aware that a large and influential portion of the population simply do not or will not accept this link.  See this from Guardian April 30th 2015:

    'Am I being executed?' Brazilian killed by Indonesia unaware until end, says priestPriest who counselled Rodrigo Gularte – who had been diagnosed with paranoid schizophrenia and bipolar disorder – says he tried in vain for three days to to explain to the inmate he was about to die"

    I have not read all the hundreds of comments on this article, but people objected to the execution for 3 main reasons: objection to death penalty; drug dealing should not be punished;  procedural errors.  No one seemed at all bothered by the fact that a psychotic person was being shot, when it is surely beyond argument that the disordered thinking and poor judgement in psychosis can lead to crime.  For them, no psychosis: no crime.   Would any representative of a mental health organisation like to take the opportunity here to speak up for the criminally insane?

    Lewis Alan Opler · Columbia University

    reality testing is part of cognition....but people are using terms in differing ways....

    my point was that persons with schizophrenia have problems with information processing which can lead to misperception....

    my bottom line is that people kill other people for all kinds of reasons, and that to single out persons with schizophrenia misses the big picture

    Since my comments apparently are like a red flag to a bull, let me further upset some of you: I am also against the death penalty for anyone

  • Meaghan Roy-O'Reilly asked a question in Chimerism:
    Has anyone successfully transplanted male bone marrow into female donors?

    I know the reverse is possible, just wondering if anyone has any experience or literature they can recommend on male to female bone marrow chimerism. Thank you!

  • Kenneth M Towe added an answer in Climate Change:
    What is the climate change induced increase (per decade) in surface water temperatures and salinity in the worlds oceans and seas?

    Climate change induced an increase in the surface water temperatures and salinity in various oceans and seas in the world. I need the amounts of their increase per decade in past several years. Please attach the article as references with your valuable reply.

  • Mark Leney added an answer in IgG:
    How to avoid IgG precipitation of purified IgG?

    I purified IgG from human serum using protein G, dialysed it with Tris 10 mM-NaCl 140 mM pH = 7,4 and then concentrated it using Amicon.

    However from 6 mg/mL my solution became cloudy.

    Do you know how can I avoid IgG aggregation/precipitation?

    This should be possible as the concentration of polyclonal human IgG used in medicine is from 10 to 50 mg/mL.

    Mark Leney · University of Massachusetts Medical School

    The comment on isoelectric point is a good one, however, a polyclonal IgG prep like this will not have a single isoelectric point. A quick review of the product labeling of commercially supplied human intravenous immune globulin (IVIG) shows that these drugs are formulated between pH 4 and 6.8... 4 seems very low, try 6.0 - citrate is very effective for monoclonal stability - no reason it shouldn't work for you. You might also want to consider physical handling and the container you are using as other causes of precipitation, gentle handling and clean/particle free (i.e. washed and rinsed with a high quality water) Type 1 USP glass might help.  Polysorbate can also help, try adding 0.01% Tween/PS-80 after you buffer exchange. 

  • Olumuyiwa Yinusa asked a question in Stock Markets:
    Is there a survey of literature on oil price volatility and stock market returns?

    I need a survey of literature on oil price volatility and stock market return if there is any?I am current writing a paper on this topic

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

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

    Stefano Quattrini · Ordine degli ingegneri della provincia di Ancona

    In the sense of CMBR cosmic microwave background radiation, astronomers are using it successfully as a absolute rest frame in order to measure the direction and speed of objects.

    We can certainly affirm that we can measure our motion relative to this CMBR absolute frame,  difficult to say that such rest frame is the same as the vacuum rest frame where the EM constants,  which allow the propagation of such radiation, belong.

  • Gautam Patel asked a question in Harmonic Analysis:
    How to validate ansys harmonic analysis result?

    I have modeled chimney in ansys WB. I got result of Harmonic analysis "Total deflection". How to validate harmonic analysis result?

  • Iman Khodadadi asked a question in ADD:
    What are the factors of increasing security coefficient channel ?

    hello ...please add your idea .

  • Daniel M Cohen added an answer in Ethanol:
    How can I eliminate ethanol contamination from phage DNA samples?

    I isolated M13 phage DNA from bacteria cells with NaI and ethanol steps (for sequencing of phage DNA), but I got very low values of 260/230 as 0,2. I think I have ethanol contamination in my samples. Could anyone help me how I can eliminate ethanol contamination from my DNA samples?

    Daniel M Cohen · University of Pennsylvania

    I agree wholeheartedly with Geoff. Ethanol would not cause a change in A260/A230 measurements. If your DNA is not working in downstream molecular biology applications, it may require additional clean up to remove contaminating protein or RNA (this would be apparent in your A260/A280 ratio). It might be helpful to post all the details of your protocol to get the best feedback on how to optimize.

  • Bassiaka Ouattara asked a question in DNA Sequencing:
    How to manage low quality of DNA Sequencing data?

    Hi everyone,

    I received my DNA Sequencing data from a compagny. Unfortunately the quality of sequencing is low (mean QC value is about 12). Are these data reliable?  What alternative do I have and how to manage these data?

  • Apurva Kumar added an answer in Triglycerides:
    Can someone help with a calculation of triglyceride amount in liver tissue?

    I extracted lipids using Folch technique and evaporated the chloroform/methanol mixture and resuspended the lipid in 200-uL of DMSO. I then determined the concentration of triglyceride (mg/dL) using an assay kit. To determine the amount of triglyceride (mg), do I multiply the concentration by the original sample volume (before evaporation) or the resuspended volume. I am slightly confused as I have seen others multiply the original volume.

    Apurva Kumar · National Institute of Mental Health and Neuro Sciences

    Determine tg in an aliquot

    Normalize it to weight. U need to have written down the weight of the tissue which was used for preparing folch extract. Assuming u used all the extract quantitatively, all the triglyceride from the amount of tissue u started with is in 0.2ml of DMSO. 

  • Anyone who can share a rapid method of virus purification without involving hi tech equipments like ultra-centrifugation?

    I have a virus isolated in cell culture. I am going to extract virus RNA and want to get rid of cellular RNA before sharing sample to NGS facility. Anyone who can respond or guide, please?

    Wiktoria Suchorska · Greater Poland Cancer Centre

    I used Amicon ultra columns Millipore. Now they have something new: Millipore’s Fast-Trap Adenovirus, Lentivirus and Adeno-associated Virus Purification and Concentration Kits provide a fast, safe, and easy alternative for viral purification.

  • Is the cancer cell triggered to divide as a consequence metabolic disequilibrium?

    Recent research suggests that there may be a close relationship between the likelihood of developing certain types of cancer and quantifiable changes in the dynamical behavior of cell metabolism consequent upon inheritable mutations in mitochondrial DNA.This begs the question as to the relationship between metabolic disequilibrium and cell division that might suggest alternative strategies for the prevention and treatment of cancer.

    If it can be shown that cell division is primarily triggered by instabilities in the cell's overall dynamical behavior consequent upon it being unsuccessful in finding a 'metabolic solution' to its' environmental boundary conditions then a possible alternative approach to the treatment of cancer would be the identification of the root cause of the metabolic instability followed by a treatment to rectify it. 

    Stagnaro S., Caramel S. The role of mitochondria and mit-DNA in oncogenesis, Quantum Biosystems. 2010, 2, 221-248, 2010.

    I am not sure of that. Retinoids are Differentiating Agents, and their prophylactic/preventive use led to increased cancer incidence in many instances. Please go through my article carotenoids and commonsense uploaded in RG.


  • Ghaleb AL-Dahash asked a question in Laser Ablation:
    What is the best method to preparation of quantum dot or grain size within 5-15 nm for Cd plate in Methanol ?

    Quastion to all who work in preparation of nano-particles by Laser ablation in liquids,to get a quantum dot or grain size within 5-15 nm for Cd plate in Methanol by laser ablation.

  • Davie Mdumuka added an answer in Limestone:
    How do I improve on the blasting results in order to reduce costs in a quarry?

    How do I improve on the blasting results in order to reduce costs in a quarry with too much overburden and heterogeneous limestone bands or seams?

    the quarry has discrete limestone pockets and usually mined at break-even ratios. sometimes the cutoff grade is never sustainable for mine operations.

    This quarry is in Zambia, chilanga run by Lafarge cement plc.

    There is water on the lower bench flow.

    Davie Mdumuka · Lafarge

    dear singh thanks for a rich response.......I am very much appreciative for your academically sound response. God bless

  • Frederick Dayour added an answer in Outliers:
    Is there a specific way of removing outliers from a data set that has a non-normal distribution?

    I am working on validating a questionnaire and I need to ensure that there are few (or no) outliers that might affect the factor analysis process. Is the outlier labeling technique (Hoaglin, Iglewicz) applicable to non-normal data?

    Frederick Dayour · University for Development Studies

    I think one way is to run frequencies and examine data with the eye. You can then go back to the data to delete outliers.

  • Roberto Braga added an answer in PZT:
    Is the nonlinearity of a PZT applied to interferometry still a problem?

    When we use a PZT to provide phase-shifting in interferometric applications we have to be aware of its nonlinearities. Today we have new PZTs, and I would like to know if we still face the nonlinearities compromising the results.

    Roberto Braga · Universidade Federal de Lavras (UFLA)

     Hi Ilya,

    thanks. I will read the paper.



  • What do decrease wrong in a communication system depend on ?

    hi my friends ...