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  • Juergen Hahn added an answer in PID Control:
    How to tune a mulit-loop PID controller (in MATLAB) ?

    I'm interested to design a PID controller for two links robotic arm (one for each joint angle), I got very bad response by few trials. So, is there feasible method could be used to figure out this issue.

    Any suggestions?

    Juergen Hahn · Rensselaer Polytechnic Institute

    If you want to design multi-loop PIDs then I would consider using the relative gain array (RGA) to determine which manipulated variables should be paired with which controlled variables. You can then tune the controllers individually; just keep in mind that the controllers should not be very aggressive as your tuning ignores the interactions amongst the variables that exists.

    If you find that the interactions are significant then using some multivariable approach, e.g., model predictive control, may give significantly better results.

  • Abdul M M Ziyath added an answer in Sand Dunes:
    How do we determine the source of dust storms in the area?

    Although determining the origin of sand storms on the Earth as well as possible, But it is difficult for dust storms.  Because this storm covers a large surface area and the specific days, and also dust storms do not always originate from sand dunes.

    Abdul M M Ziyath · University of Peradeniya

    Back trajectory analysis can be useful in this case. Please check the attached article.

  • Askold. S. Belyakov added an answer in Lathe:
    Which locations are best suited for collecting vibration signal using Accelerometer in CNC on Tool holder or other location for tool wear monitoring?

    Which location should be best suited for collecting vibration signal using Accelerometer in CNC lathe machine on Tool holder or other location for tool wear monitoring?

    how many Accelerometer (Uni axial) mounted on Tool holder or other location  for best measure tool wear on CNC lathe machine?

    Askold. S. Belyakov · Institute Physics of Earth Russian Academy of Sciences

    See and hear this link: http://earthsciences.typepad.com/blog/2012/05/listening-to-seismicity.html  
    The instrument measures the rate of acceleration is better suited for your application. Fitting on the tool holder perfect, but using a new instrument, it may be sufficient to install its lathe and measurement of vertical oscillations. In the above link, there are indications source of information about the device.

  • Is anyone aware of mobile or electronic health trials on diet or physical activity in underserved populations?

    For a review I am looking for studies that have used any form of mobile technology and/or the internet etc. for promoting healthy diet and/or physical activity in underserved populations (older adults, persons with disabilities, minorities...) and/or low- to middle- income countries. 


    Bahram Sangelaji · National Multiple Sclerosis Society

    Dear Andre

    I send you some articles about telerehabilitation for increasing the physical activity in MS condition. I hope they will be helpful for you.

    you can use this link as well




  • Can I re-use my ELISA Standard Solutions? stored at RT for week?

    I used a standard and diluted it in the appropriate solution.

    Ran out of standard so I'm wondering if i can used my old standard solution that's been sitting around for a few days at RT. 

    It's Mouse IL-6 Recombinant protein.

    Dogan Doruk Demircioglu · University of Tuebingen

    Absolutely not! Even storage at 4°C let it decompose rapidly. We tried in in our lab, and could see clear decomposition effects even at -20°C. eBioscience therefore recommend storage at -80°C!

    Cytokines have a quite short half-life, which differs between some minutes up to some hours, depending on the paper. I would be surprised, if it would still work.

  • Cherine Akkari added an answer in Geoheritage:
    Has any country published guidelines for the environmental impact assessment of projects affecting geoheritage?

    We have produced a manual book with guidelines for the incorporation of geoheritage into environmental impact studies. It is published by the Spanish Ministry of Environment and the Geological Survey of Spain. We wonder if there is any similar book published in otehr countries.

    Cherine Akkari · Université de Montréal

    Hi Enrique,

    There is a book called 'Geoheritage of East and Southeast Asia'. Here is the link:



    And here are some additional readings:





    See also the attached file below


  • Daniel Kovach added an answer in Neural Networks:
    Any software for Artificial Higher Order Neural Network?

    Please can anybody help me out with a name of software(s) that Artificial Higher Order Neural Network can be applied?

    Daniel Kovach · Gayatri Vidya Parishad College of Engineering

    I have an implementation I wrote in C++ with Python bindings.  You can specify an arbitrary structure for the neural network using a dot schema.  It also supports recursion. Its part of a more general open source project of mine called "AILib". You can download it here:


    DISCLAIMER: its still in beta mode, so forgive the occasional compiler error, especially if you're using Windows (its been tested in Ubuntu 12.04 and Mac OS X).

    If you are interested in something a solution a little more 'out of the box', R has a package called 'nnet' which has a parameter called 'hidden' in which you can set the number of hidden layers.  There's a pretty good article about it here:


  • John Tainer asked a question in Data Storage:
    With the rate of DNA sequencing increasing faster than data storage or computer speed, what are the best ways to benefit from sequence information?

    Are there near term benefits that we should be better harvesting? How do we move ahead effectively with sequence data?

  • Is there a connection between religion and immigration or naturalization policy?

    Is there a country that links (today or in the past) its immigration, naturalization or citizenship policy to a certain religious affiliation?
    In Israel this connection is obvious, so I wonder whether there are any parallels. 


    Netanel Fisher

    Faranack Nader Benz · University at Buffalo, The State University of New York

    It depends on what geographical area, and geopolitical condition a group is in. More importantly, the connection between religion and migration varies based on what era, and time- variable you are thinking about. Today, religion is a very different instrument than thirth years ago; in the past it was a spritual and trusted tool to "divide & rule", but in current time, it is more of a globally political- instrument to "divide & rule" the common cultures, under shadow of economic interests. As a result, the dependent variables of migration and religion are under umbrella of many independent- variables; as specific your hypothsis goes, as the choosing of an suitable independent variables.   

  • What are the approaches that we can use when we have feature sets of variable length?

    I am trying to build a feature set from disparate sources for a classification problem. Unfortunately I could not arrive at a feature set that as same dimension for each of the instances in my data set. I am curious to know whether people have encountered similar problems before and how they tackled it.

    Any suggestion is appreciated. Thank you so much for your time and help in advance.

    Karthik Ganesan Pillai · Cerner Corporation

    Thank you!!!

  • What would you do if you received a report from the reviewer of your paper asking for a major revision, with which you completely disagree?
    What would be your response? Would you appeal to the editor by asking him/her to make the final decision, would you be weak and amend what you believe is right, would you argue back with facts, would you re-submit the paper to another journal?
    Macho Anani · University of Sidi-Bel-Abbes

    Dear Mahfuz

    It never happen to me that a reviewer was convinced with my point of view. It is perhaps a question of vanity but I never succeeded to change the reasoning of a tough reviewer. You know that they are renowned by their hard-headed since they have a reputation to ensure.

  • Did the painter Georges Braque know Marcel Duchamp, Robert Delaunay and Hans (jean) Arp in the period before or during 1910-25?

    By "know", I mean being a friend, collaborator or any other relationship where Georges Braque interacted with them for all or part of the above period.

    Mitali Banerjee · Columbia University

    thanks Jermey! This is helpful. I was wondering, if this also means, Braque knew Delaunay?  And, I appreciate any thoughts on whether Braque knew Arp.

    To give you some context for my question, I am trying to get a sense of the social world of Braque--the people he was friends with, collaborated with or had any other relationship with before or during 1910-25. I understand that Sonia Delaunay's ex-husband, Wilhelm Uhde, was Braque's dealer.  Taken together, all this might obviously indicate  that Braque knew Robert Delaunay. But I am yet to come across evidence documenting  this.  Similarly, I understand, Braque and Arp were guests of American patron Paul Nelson around 1927 at the latter's house in Varengeville. But it is not clear if this means Braque and Arp knew each other before or during 1910-25.

  • Brian Cluer added an answer in Fisheries:
    What impediment poses the greatest challenge for a more thorough implementation of Ecosystem-Based Fisheries Management?

    Would it be: technical, limited data, scientific, cultural, philosophical, logistical, organizational, structural, personality driven, educational, or ???  What does the community think?

    Brian Cluer · National Oceanic and Atmospheric Administration

    I don't think the fisheries management community has come to grips with the scale of the problem.  

  • Does anyone know, how can I assess the impact of climate change on water balance in river basin using monthly input data?

    I conduct study that aim to assess the impact of climate change on water balance in river basin. My data are monthly (Temp, PPT, and Runoff) for number of stations spread all over the basin for the period 1960-2012.

    Shahadat Chowdhury · Australian Government

    I am adding a 4th step.

    4th. Downscale the hindcast (say 1970 to 2000) of PPT, Evap from the same climate model using the same method that you have done for 2020 to 2100. Run your calibrated hydrological model using this hindcast set as input. Now compare the observed river flow for 1970 to 2000 against (1) your original calibration (2) results from this hindcast set. This will give you an idea how reliable the climate model you are using. If the hindcast is bad than the forecast (2020 to 2100) may not be reliable or vice a versa.

  • John Tainer added an answer in Cancer Biology:
    What types of proteins or complexes might be optimal targets for improved cancer drugs and why?
    As we learn more from the cancer genome project and therapeutic strategies that provide long-term benefits, what types of targets might allow us to do better? Many successful cancer therapies directly or indirectly damage DNA, and many target replication in some way. Whereas kinase and other inhibitors can show strong initial impacts, resistance seems to be a greater problem with some types of inhibitors. Should we be aiming for drugs that rapidly kill cancer kills but may cause resistance by strong selective pressure or those that weaken cancer cells but better avoid resistance.
    John Tainer · The Scripps Research Institute

    I wonder if allosteric targets for proteins such as kinases might prove a better long term strategy than trying to block the ATP binding sites which will obviously have strong similarities and require drugs to compete against 1 mM concentrations of ATP inside cells.

  • Is it possible to show explicitly the function $\varphi_{x}\in C^{0,1}(R^{n-1})$ that is related with each $x\in\partial B_{r}(0)$?

    We know that an open ball $B_{r}(0)\subseteq R^{n}$ is a smooth domain. It follows that this is a Lipschitz domain. Is it possible to show explicitly the function $\varphi_{x}\in C^{0,1}(R^{n-1})$ that is related with each $x\in\partial B_{r}(0)$?

    Christopher Jason Larsen · Worcester Polytechnic Institute

    You could use identical functions, oriented correctly, so all Lipschitz constants are the same. You could also make the constant arbitrarily small by taking small arcs. 

  • David H Anthony III added an answer in Enteritis:
    If I do not have a DOI may I use a URL and if so, where?

    I have a number of online links to scholarly work I have done that may not have generated DOIs. However, I do have URLs for these. How may I enter the links?

    David H Anthony III · University of California, Santa Cruz



  • Shawkat M Islam asked a question in Quantum ESPRESSO:
    Raman Spectroscopy on Quantum Espresso?

    Is it possible to calculate Raman spectra using (1) VASP or (2) Quantum Espresso?

  • Is research funding a zero sum game and the problem with U.S. research an “erroneous assumption of never-ending rapid growth in biomedical science”?

    Is the problem with US research an “erroneous assumption of never-ending rapid growth in biomedical science” as noted by Alberts B, Kirschner MW, Tilghman S, Varmus H. Rescuing US biomedical research from its systemic flaws. PNAS 2014 111: 5773-7? U.S. medical research has been cut 25% in real dollars since 2003. By contrast, medical costs are increasing without regard to the limits suggested for science funding as evidenced by the increase in health insurance premiums of 80% over this period http://kff.org/report-section/2013-summary-of-findings/ . So why should the investment in basic research that provides advances in treatments and keeps people out of the hospital not increase proportionately? Does flat or decreasing funding for science make any logical sense with the growing problems of antibiotic resistance, emerging pathogens, aging population, and increasing environmental stresses. 

    Steingrimur Stefansson · HeMemics Biotechnologies Inc

    Hi John, I think that the major problem with research funding is that it is basically an ol' boy's network.

    People doing mediocre science are being funded just because they are friends with members of grant review panels.

    If you are an outsider applying for government grants, well, you are F'ed.

    Investment in basic science has, and will always generate benefits for patients. To me the problem, in this funding climate, is how to identify and fund promising technologies without politics and friend-networks being involved.  

  • Negin Minaei added an answer in Building:
    What's the case study of a successful indoor ecopark?

    What's the case study of successful indoor ecopark? What thing should be pay attention if the designer change the original building such as a tall building or a factory to an indoor ecopark? Is it good to built a wildlife indoor ecopark in the central of city?

    Very interesting topic!

    For indoor Eco-parks, you may be able to find good examples in botanical gardens across Europe (Switzerland, ...) and UK. As most of botanical gardens have a number of buildings with different controlled climates to grow plants. You shall be able to find architectural standards from analyzing couple of case studies if there is not any design book about it which I doubt. Look in landscape sources.

    For changing a an original function of a building to a new function, the terminology you need to look for is 'regeneration' and 'renovation'. 

    I think yes, it is a good because you bring nature to the city center which creates a different atmosphere and if you can surround it with greenery or design it in a way that is linked to other green spaces around it, then you are creating green corridors which helps biodiversity. In London and many other European cities, you see wild life even in parks and public green spaces. Psychologically it has a positive effect on inhabitants.

  • Michael Bletzer added an answer in Burial:
    Do you know any leper burials (not leper hospitals) that were not isolated from the rest of the burials in a single graveyard?

    I'm interested in (medieval) cases where burials with people who had leprosy were not isolated, but were included in the settlement's graveyard, thus perhaps showing some sort of care for the sick etc.

    There's a case in Croatia where 4 leper burials were found in a single graveyard of all together 112 burials. The leper burials were obviously not isolated, the artifacts found in the graves didn't differ from other graves and there were even two dual burials (sick female + healthy male).

    Michael Bletzer · DMG Four Corners Research, Inc.; Jornada Research Institute


    this appears to be a case of non-isolated burial: M. Rubini and P. Zaio, Lepromatous leprosy in an early mediaeval cemetery in Central Italy (Morrione, Campochiaro, Molise, 6th–8th century AD), Journal of Archaeological Science 36, 12 (Dec. 2009): 2771-2779.

  • Colin Baker asked a question in Suspensions:
    How can I obtain a stable suspension of <50 nm Al2O3 nanoparticles?

    They need to be agglomerate free. They can be in any aqueous or alcohol solution. These are commercially available, but the vendors generally don't tell you how it is done.

  • What is the difference between Comparator and Control in RCT?

    May you explain to me what exactly is the difference is between 'Comparator' and 'Control' in randomized controlled trials?

    Elmer Villanueva · Xi'an Jiaotong-Liverpool University

    Ok, I'll bite.

    A control group is one that does not receive the intervention of interest. In a simple case comparing drug A versus placebo, the control group is clear. The comparator is a much more general concept. For example, take a factorial trial of drug A and surgery. In such a trial, there are four groups:

    Group 1: No Drug AND No Surgery

    Group 2: Drug but no surgery

    Group 3: Surgery and no drug

    Group 4: Drug AND surgery

    The concept of a control group is much more hazy in this case. Drug is still a comparator against surgery, though.

    In another example, say you're testing four doses of the same drug:

    Group 1: 75 mg

    Group 2: 150 mg

    Group 3: 300 mg

    Group 4: 600 mg

    Since all groups receive the drugs, are there no controls?


    I'm sure others have their views.

  • John Tainer added an answer in Funding:
    Why are impact factors important and how could we make better short-term metrics for the value of scientific research?
    Impact factors can be a negative distraction from quality and science because they can be economic drivers for some scientific journals and researchers. Yet scientific impacts are often only realized over the long term so it is difficult to assess whether funding research is a great investment or not. I suspect impact factors are so compelling because they provide an immediate if flawed metric indicating that invested funding may payoff in some type of long-term benefits to society and the economy. If this is true, how can we do better in providing short-term metrics supporting the value of scientific research?
    John Tainer · The Scripps Research Institute

    I suppose with increased computing it will be more possible to follow multiple things for an investigators publications such as downloads and other impact. Certainly looking at how much a given paper is cited is more important how the journal overall.

  • What part of energy can be saved by recuperation in drying wood pellet ?

    About 70% of the total energy consumed for the production of pellets used for drying wood.

    Miguel Angel García-Alvarado · Instituto Tecnológico de Veracruz

    Assuming that woods pellets would be dried with hot air, the energy that can be recovered depends of the outlet air temperature and saturation. If outlet temperature is greater than environmental air temperature, a heat recover (a heat exchange) may be installed at the drier output to pre-heat the input (environmental) air. If outlet air water vapor saturation is lower than 80%, a fraction of outlet air can be recycle to input air saving energy during input air heating. The quantification of this energy saving depends on the exact values of temperature and saturation of outlet air.

  • J.J. Fung added an answer in Protein Purification:
    Which laboratory offers protein purification service and sequence identification for a fee?

    What are trustable commercial laboratories doing protein identification and purification.

  • Martino M Gabra added an answer in DMSO:
    What could be your explanation of bacterial contamination?

    I've encountered a bacterial contamination in cell culture medium (with P+S antibiotics) and even in a solvent (DMSO). What could be your explanation of such immunity expressed by bacteria?

    P.S. I use all of the required sterility measures

    Martino M Gabra · University of Toronto

    Did you do a just reagents control? If your reagents are infected than something should grow and if your reagents are cheap then just replace them. My friend had a similar problem but he found moving slower minimized contaminations

  • How to elute a protein band of interest from SDS-PAGE or NATIVE-PAGE gel ?
    How to elute a protein band of interest from SDS-PAGE or NATIVE-PAGE gel ?
    John Sebastián Barraza-López · National Polytechnic Institute

    Hello, I would suggest you take a look at this protocol, it helped me with the the same needs you have.

  • Are our thoughts learned responses to our behaviors ? If not, what is the origin of the first thought in human mind ?

    I studied about behaviors, and they are learned most of the time, but as the behaviors are manifestations of thoughts feelings, so how a first thought comes in human mind. 

    Jelle van Dijk · Utrecht University of Applied Sciences

    Dear Zoaib.

    This could be one of the starting questions that can take you further into psychology, if you like to think about such things. Perhaps thoughts and feelings are manifestations of behaviors. The old father of psychology William James thought so, when he wrote about how emotion, say 'fear', is just the internal response you get when you find yourself running away from a bear in the forest. The behaviorists (e.g. Watson, Skinner) were even more extreme, saying that thoughts and feelings are non-existing in the first place, or at least they are not scientific, only things that are externally observable, like the stimuli that hit us and the behavioral response we give and so we should make explanations of behavior by only referring to stimuli and responses and how they get associated through 'conditioning'. The cognitivists, which came as a response to the behaviorists, took 'information processing and storage' as their basic model of what goes on in our mind. In their terms, everything mental is made up of bits of information that get to be combined in all kinds of complex 'representations' of the world around us and the set of basic building blocks with which you can make these mental representations got to be called the 'language of thought', as it was really thought of as a kind of language, with words that had meanings and rules for combining the words into statements that stood for all the things you know (or believed or wished or desired). But if all knowledge is made up of a set of elementary information 'building blocks', the basic language structures of the 'language of thought', then where did these building blocks themselves come from? Jerry Fodor, one of the most radical cognitivists, once argued that it must be innate: inborn. If that is so, your question gest passed on to the biologists: how did the human brain got to evolve in such a way that it 'suddenly' contained a 'language of thought machine' inside, while other animals do not seem to have such a thing? Come to talk of animals, there is even a paper showing how behavior is possible even in the bacteria E. Coli. This little critter can move up and down the sugar gradient to find better food sources, and when there is no sugar it will just randomly wander around until it finds a sugar trace again. Pretty smart, huh? But the E.Coli bacteria doesn't have a nervous system. So apparently you don't need a brain in order to show 'intelligent behavior'. Some of the responses above talk about brain and mind as if it is the same thing - the E. Coli might disagree. Finally your question reminded me of a text by a famous anthropologist, Clifford Geertz, who talked about behavior and what causes behavior, and how scientists try to explain 'where behavior comes from'. In a nutshell, he basically says what Micah says in his first line, that 'thinking is behaving'. They are not two different things, one 'causing' the other: they are the same thing but just looking at it at another level of description. For example, think about a 'behavior' like 'typing a text'. I am typing a text right now. But on another level of description I am "moving my fingers of the keypad". Which one is the real one? Is the 'typing' responsible for moving the fingers? Or is moving the fingers the real thing and is 'typing' just a word we use for summarizing all these movements? Going up in levels: am I typing, or am I 'getting a message across to Zoaib?". Or am I "just browsing some Q&A websites because I was a little bored and needed some distraction" - and so on. Geertz warns us not to try to reduce behavior to something else ('the mind') as if that is the 'real' thing and behavior is just the 'appearance' of what goes on inside. Good luck with your studies!!