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  • What is the best method for avoiding contamination in cultivation of bacteria?
    We have a big problem in our lab, as we have different types of bacterial and fungal contamination. We do our best to avoid this by using UV sterilization, Laminar air flow ,and other techniques.
    Dr. Hussein Al-Dahmoshi · University of Babylon
    via using Lamina Air flow
  • What makes the Raman spectra of bulk glass and its corresponding powder different?
    To be more clear, how can you explain that the Raman spectrum of a bulk glass sample features some other variations than that of the powder of the same bulk glass?
    Mohammed Zaki · University of Limoges
    Definitely, I will try this! In this regard, I am thinking about sandblasting as a technique to increase the surface roughness of bulk glass. Do you have any recommendation for how to perform this experiment?
  • Aryan Amoli added an answer in Abaqus
    How to model a specimen crack propagation fracture mechanics method under cyclic loading in Abaqus CAE?
    What is the element that I should use it to find fracture intensity factor?
    Aryan Amoli · University of Tehran
    I'm quoting Abaqus "Analysis User's Guide" here: "[Contour integrals] can be used only with two-dimensional quadrilateral elements or three-dimensional brick elements when used with the conventional finite element method"
  • Is the coomassie stain able to interact with DNA?
    I have electroblotted on a pvdf membrane a 4-20 PAA-TGS gel run with samples 3 lanes containing DNA and a recombinant protein and 3 lanes of control containing only the protein. All the sample have the same concentration of the protein and of DNA. I know that my protein is not stained by the Coomassie. Once i have performed the ECL, I have the expected bands of my protein (in the low molecular weight region) in all the lanes (as I expected) but in those lanes where I added DNA there is a band in the very high molecular weight regions that appears as a ghost and the bands of the protein in this step have a reduction of intensity with the respect of the lanes where I did not loaded any DNA. Furthermore these bands are colored by the coomassie stain. What happened? Did the coomassie stain interact with DNA? Ir it is my protein that has interacted with the DNA and was stained by the coomassie?
    Daniel Rieck · Washington State University
    Stefan has some excellent suggestions above; you need to run the proper controls, especially the DNA-only control, before you can gain experimental confidence about what is going on with the high molecular weight bands you are observing. The mechanism by which Coomassie blue stains proteins involves two forms of non-covalent bonding under typical conditions. 1) Van der Waals forces involving nonpolar amino acid residues. 2) Electrostatic interactions predominantly involving basic, positively charged amino acid residues; this is why proteins with predominantly acidic, negatively charged residues are stained more faintly by Coomassie. DNA is negatively charged and does have hydrophobic regions, so I think it is possible that the faint heavy band could be your DNA without any protein bound to it. Of course, the other possibility, as hinted at by Stefan above, is that the protein interacted only weakly with the DNA and what you are observing is stained protein. Therefore, at this point, it is my firm opinion that you cannot properly interpret your result without further testing.
  • What percentage agarose for protein-DNA 50bp binding assay?
    Would a 3% gel be suitable for monitoring a 50bp (pure) DNA oligo on an agarose gel and then its band-shift on binding to a protein in the gel? Is dissolving 3% agarose significantly difficult compared to 2% (i.e. is 3% harder to reproduce)? I am assuming there is no predictable difference between use of buffers TAE and TBE, and hence intend to use TAE as it is supposedly less prone to precipitation and I envisage the stronger buffering capacity of TBE will not be required for the short-to-average run times for 50bp oligos. Thanks
    Dr. Hussein Al-Dahmoshi · University of Babylon
  • Dimitrios Nikolopoulos asked a question in ALL QUESTIONS
    General Issues
    I would like to draw attention to those who upload full published papers in PDF format, that the final publication is copyright material of the publishers (Elsevier, Springer etc.). Therefore, it is ILLEGAL to upload such material on social networking media as RG. Full publication files can be exchanged only on personal basis and by no means through internet. Αuthors may only upload pre-published versions of their papers. -- Dr.Dimitrios Nikolopoulos Environmental-Medical Physics Associate Professor _________________________________________________________ Department of Computer Electronic Engineering, Technological Education Institute (TEI) of Piraeus, Petrou Ralli & Thivon 250, 122 44,Aigaleo,Athens, Greece e-mail : dniko@teipir.gr NikolopoulosDimitrios@gmail.com Mobile : +0030-6977-208318 Home : +0030-213-0308432 Tel (TEI): +0030-210-5381560 Fax (TEI): +0030-210-5381436 Skype : dr.dimitrios.nikolopoulos Internet : http://env-hum-comp-res.teipir.gr/ _________________________________________________________
  • Can we have OPC as a control mix for a mix containing High early strength cement, fly ash and silica fume
    Kasım Mermerdaş · Hasan Kalyoncu University
    As long as you retain exactly same mix proportions such as w/c ratio, dosage of superplasticiser, fractions of fine and coarse aggregates, etc, you can use any type as a reference to compare the performances of other types.
  • Bernd Schmeikal added an answer:
    Is mathematics a human contrivance or is it innate to nature?
    Do we invent mathematical forms as we need them and then merely discover their emergent properties later? Or are those mathematical forms innate to nature, and are hence discovered rather than invented? Does it really matter to science, which way around we view this? Is it just philosophy or could there be real consequences? https://www.researchgate.net/publication/256838918 http://www.huffingtonpost.com/derek-abbott/is-mathematics-invented-o_b_3895622.html
    Bernd Schmeikal · Vienna Institute for Social Science Documentation and Methodology
    Marc and Dragan, confronting bravely? What for? Marc I read into your ' On the thermodynamics of multilevel evolution'. I searched for a citation of Nick Lane, say, Chance or Necessity? Bioenergetics and the Probability of Life. Journal of Cosmology, 2010, Vol 10, 3286-3304. http://journalofcosmology.com/Dbiogenesis107.html But as some say, science is a subjective undertaking.
  • Political Science is confined to studying institutional or systemic aspects of governance - is this true?
    For many political scientists, 'politics' means who gets what, when and how in society (Lasswell and Kaplan, 1950).The concept of politics adopted by political scientists influenced by American and British traditions is narrow, confined to the political system whose functions are: rule making, rule application and rule adjudication (Almond and Coleman, 1960). If that was so, what has changed in the outlook of political scientists in the past fifty years? Are they still looking to find solutions when problems arise or are they looking at the needs of the end users - people, their aspirations and dreams - and calibrating the old (even if it means to cast off the old like Democracy, Socialism, Capitalism, etc) to find newer systems that are in tune with the times?
    David Risser · Millersville University
    The investigation of power is a normative endeavor. As one of my former professors, Steven Lukes, has claimed: the identification of an exercise of power by either an individual or an organization is at the same time an ascription of moral responsibility for the effects of that action. The definition of power bridges the so-called is/ought dichotomy. Although many of its features and effects can be grasped empirically, it is "an essentially contested concept" as well, with competing conceptions of power having different and often conflicting moral and political implications. I have studied and taught political theory for some years, and I believe our understanding of power is intimately related to other fundamental concepts and values, such as consent, democracy and tyranny, liberty, justice, and legitimacy, all of which require facts AND moral values in order to be addressed properly. In fact, all the social "sciences" rest upon, imply, and consciously or not, advocate moral premises of one sort or another. (Please see e.g., Wm. Connolly's The Terms of Political Discourse)
  • Abdullah Diabat added an answer in Tectonics
    How i can compute Paleo stress for fault slip data?
    How i can use T-tecto to compute the Mohr Diagram? I used inverse analysis but there is some method or parameter i could not understand, or how i to used with my parameter.
    Abdullah Diabat · Al - Albayt University
    You can use the Win- TENSOR Program of Damien Delvaux which is available download from the net. It is a simple and good , the input data required are dip/dip direction and plunge/ plunge direction in addition to the sense of movement for each fault-slip data.The data set can be separated manually or automaticly
  • How to calculate mass flow rate for heat exchanger ?
    i want to extract heat from stationary saline hot water. saline water is at temperature of 60C, i want to heat up another fluid from 25 to 50C. LMTD is 14.06, di =16mm do=20mm, length=1.8 m; which method should be applied to know optimum mass flow rate ?
  • Big bang theory indicates that universal expansion will continue but where it is expanding and is it going to stop after several million years.
    Once the universal expansion stops will our universe start converge or collapse and will form another big bang and the new universe will start its creation and this process will go on and the creation and recreation will continue and the universe will remain infinite with expansion and contraction.
    Charles Francis · Jesus College, Cambridge
    Expansion doesn't mean that the universe expands into a "where", it means that "where" gets bigger. The life of the universe is measured in billions of years, not millions, but current thinking is that the evidence shows that accelerating expansion will continue indefinitely. I've given some explanation at http://rqgravity.net/LargeScaleStructure, with the maths and some of the ideas explained earlier in the site
  • Does anyone know any tool that compares the sequence of 2 enzymes and answer if they are isoenzymes?
    I need to know if two enzymes are isozymes, but do not know their active sites. Is there any tool to identify active sites and to make this comparison.
    Chien-Jui Huang · Ghent University
    Hi Silva, if you have the sequences, try this http://www.ncbi.nlm.nih.gov/Structure/cdd/wrpsb.cgi
  • Aldosterone synthase mutation analysis- where to send it?
    Dear Colleagues: I am trying to send blood for mutation analysis of Aldosterone synthase deficiency (CYP11B2) in zona glomerulosa in the United State but haven't been successful. Only places I have founded is research labs in Europe. Any information of US labs or Europe labs that does the genetic would be appreciated. Thanks.
  • Ingo Tjards added an answer in Energy
    What do you think are the most important personal characteristics of a successful researcher?
    Is there in your opinion some personal characteristics that are recurrent in successful researchers? What is opinion about the following personality traits? 1. Intellectual curiosity, 2. determination, 3. self-motivation, 4. competitiveness, 5. team-work capabilities, 6. humbleness, etc. Are there other relevant issues that I have not mentioned? Do you feel there is a logical importance ranking among the above mentioned characteristics? Do you think the ranking depends on the specific research field or on other issues?
    Ingo Tjards · IG Eifel and Innventors Club East Frisian
    All right, and what is with economic resources?
  • Lijo Francis added an answer in Political Culture
    For what extent are researchers affected by political conflicts?
    When your country is in political conflict with another country, how does such a conflict impact the relationships between researchers? Any experience, perception?
    Lijo Francis · King Abdullah University of Science and Technology
    Of course, there are many examples of political interference that ruins the motivation!
  • Mahdi Borzooei added an answer in Advertising
    Mobile advertisement
    Iam thinking of doing an article on the impact of consumer attitudes towards mobile phone as a medium of advertising.
  • Joe Sarkis added an answer in Protein Translation
    Is it necessary to add a stabilising agent eg glycerol or sucrose when freezing a protein?
    We don't know whether the agent will interfere with a translation assay we want to do. Would proteins usually get dentaured if they are snap frozen in a buffer without stabilisation?
    Joe Sarkis · Harvard Medical School
    Check that, it could help: Effect of freezing and thawing rates on denaturation of proteins in aqueous solutions. http://www.ncbi.nlm.nih.gov/pubmed/12673768
  • James F Peters added an answer in Geometry
    Are there mathematicians, scientists or philosophers whose work you view as influencing historical events in a minor or in a major significant way?
    Do you think that the interaction between such scholars has led to the success of their work in making an impact? Scholars such as Euclid (geometry), Newton (science), Plato (philosophy) have been very influential in shaping the way we see the world. For example, Euclid’s Elements written in Alexandria around 300 B.C. became a standard work in geometry. It is one of the most widely read, translated and commented on work in European history. It was translated into Arabic around 800 A.D., into Chinese in 17th century and into Sanskit in the 18th century. The first english version of Euclid’s Elements was Sir Henry Billingsley’s translation published in 1570. Euclidean geometry has been enormously influential in shaping our view of the world. For more about this, see http://www.hf.uio.no/ikos/english/research/projects/euclid/ Plato, 428-348 B.C., descendent from kings of Athens and Messenia, student of Socrates, teacher of Aristotle, founded the Academy of Athens, one of the institutions of higher learning in the Western world. He wrote about justice, beauty, equality, political philosophy, theology, cosmology, epistemology and the philosophy of language. For more about this, see http://www.biography.com/people/plato-9442588#awesm=~oBHUNDFF6ggpWQ A central notion in Plato’s philosophy is the theory of forms. The only true being is founded upon the forms, the eternal, unchangeable, perfect types, of which particular objects of sense are imperfect copies. This theory has been enormously influential in science and mathematics. For more about this, see http://www.ams.org/notices/201002/rtx100200239p.pdf Isaac Newton, 1643-1727, son of a farmer, Professor at Cambridge University, taught optics, introduced a theory of colours of light and theory of gravitation, published his Mathematical Principles of Natural Philosophy, 1687, introducing infinitesimal calculus, co-discovered (with Leibniz). During his study of optics, Newton investigated the refraction of light, demonstrating that the multi-coloured speturm produced by prism (see attached image) could be recomposed into white light by a lens and a second prism. He showed that colour is the result of objects interacting with already-coloured light rather than objects generating the colour themselves. He designed the first reflecting telescope, demonstrating his telescope to the Royal Society in 1671.
    James Peters · University of Manitoba
    Another influential poet, philosopher and mathematician is Viktor Vladimirovich Khlebnikov, better known by the pen name Velimir Khlebnikov (Russian: Велими́р Хле́бников, IPA: [vʲɪlʲɪˈmʲir ˈxlʲebnʲɪkəf]; 9 November [O.S. 28 October] 1885 – 28 June 1922), was a poet and playwright, a central part of the Russian Futurist movement, but his work and influence stretch far beyond it. In his work, Khlebnikov experimented with the Russian language, drawing upon its roots to invent huge numbers of neologisms, and finding significance in the shapes and sounds of individual letters of Cyrillic. Along with Kruchenykh, he originated zaum. He wrote futurological essays about such things as the possible evolution of mass communication ("The Radio of the Future") and transportation and housing ("Ourselves and Our Buildings"). He described a world in which people live and travel about in mobile glass cubicles that can attach themselves to skyscraper-like frameworks, and in which all human knowledge can be disseminated to the world by radio and displayed automatically on giant book-like displays at streetcorners. In his last years, Khlebnikov became fascinated by Slavic mythology and Pythagorean numerology, and drew up long "Tables of Destiny" decomposing historical intervals and dates into functions of the numbers 2 and 3. For more about Khlebnikov's life and work, see http://en.wikipedia.org/wiki/Velimir_Khlebnikov Many thanks to Alexander Yurkin for pointing out the importance of Viktor Vladimirovich Khlebnikov. To read about Khlebnikov's radio of the future, see http://acousmata.com/post/90347897/the-radio-of-the-future English translations of Khlebnikov's poems are available at http://www.albany.edu/offcourse/issue41/cigale_translations2.html#khlebnikov Khlebnikov's self portrait is attached to this post.
  • Vahid Rakhshan added an answer in Cognitive
    How did intelligence evolve? In fact why did it evolve?
    An probable explanation can be organisms needed to survive but I think that alone can't be a reason for intelligence to evolve. Something other than survival might have motivated for the evolution of intelligence. EDITED: @Artur, I would like to define intelligence as not efficient search (considered by computer scientist) neither prediction (said by Jeff Hawkins) . It is the principle that follows three fundamental things: *Minimum Energy *Least Action Principle *Minimum Space
    Vahid Rakhshan · Islamic Azad University
    Sai these terminologies have globally accepted definitions. Using them for other purposes is simply irresponsible. You want to convey your own idea, then plz find a word for that idea. If there is no word for your idea, explain it... Your way of overloading the definition of intelligence with some **personal** definition is like I say "I am hungry" and mean "I want to go to the classroom". And justify that "for me, the word "hungry" means "intention to go to the classroom."... In your case, I would use the world "optimized problem solving ability" instead of "intelligence".
  • When using PCA to estimate urban vulnerability, what is the best way to include direct and inverse variables in a Principal Component Analysis?
    There are variables increasing vulnerability while others decrease it. What are the best pre-processing methods to account for this relationship to ensure adequate results? Is it always necessarily a max-normalization or another rescaling procedure? How can we interpret negative and positive signs in eigenvectors?
    Huda Abdullah · Al-Mustansiriya University
    you can use varimax as a rotation method . negative and positive signs in eigenvectors depends on the type of relationship if the sign is positive means the relationship between component with others is Direct correlation, and vice versa. To facilitate interpretation of results, you can use sorted coefficients by size.
  • You think about the Fordist production of knowledge?
    Believing that science has impacted and universities this type of knowledge production? What can bring about?
    Mohammad Ayaz Ahmad · University of Tabuk
    Generally used to refer to the organizational structure of production and consumption, the concepts of Fordism and post-Fordism have been applied to describe other institutional arrangements from the state to education to culture, art, and the media. Historically, the Fordist mode of production and consumption emerged in America during the turn of the twentieth century, when Henry Ford established mass production techniques in his automobile factories. Ford based his production techniques on a model of scientific management that was informed by the research of Frederick Taylor. According to Taylor, the productivity of workers could be increased if each component of the production process was broken down into simple, repetitive tasks.
  • Can anyone help with BOD value?
    I took the sample of sewage waste water from an oxidation pond and observe the BOD value is less but when I took the sample from the outlet of same pond the BOD value is high. Can anybody justify that?
  • Paul C Colby added an answer in Gravity
    In general relativity, how is gravitational force replaced by space-time geometry?
    How, in Einstein's theory of gravity, can one replace the concept of force with that of the deformations of space time? Why is the orbit of mercury described better in terms of Einstein's theory in comparison with Newton's theory? A reference link: http://www.einstein-online.info/elementary/generalRT/GeomGravity
    Paul Colby · Lockheed Martin Corporation
    I thought the number of potential gauge groups is finite? Why haven't all such "fiber bundle" theories all ready been considered?
  • Mohammad Ayaz Ahmad added an answer in Gravity
    An old question that is still fresh: Is gravity a Newtonian force or Einstein space-time curvature?
    No gravitational wave was measured yet, no graviton was detected accordingly. On the other hand no space- time curvature was observable. There is no successful experiment to validate the current theories. What is the nature of the mysterious gravity? What is the velocity of this effect ?
    Mohammad Ayaz Ahmad · University of Tabuk
  • Nicole Schlau added an answer in Animal Health
    Can anyone help with blood serum issues? We received some that are black.
    I attached a picture of what they look like because it's hard to describe. This is after they had been spun several times. One turned out okay but all of the rest are black and not spinning properly. They were collected from cattle and sent into the lab. Never seen this before and not sure what would make this happen.
    Nicole Schlau · Alltech
    Thank you! I will pass that information along. That makes perfect sense.
  • What do you know about play and development? Risky play?
    Carolyn Blackburn · Birmingham City University
    Not sure exactly what you're asking here, is there something in particular you're looking for, e.g. the benefits of risky play to children's development, the importance of play in development?
  • Mohammad Ayaz Ahmad added an answer in Universe
    Is there a reasonable alternative to the theory of the expanding universe?
    We know that our star, the Sun loses about 10^-14 of its mass per year as a result of electromagnetic radiation and particle emission. That reduction in mass should show up as a decreasing gravitational red shift. Same thing should happen to entire galaxies. But isn't it true that the galaxies we observe that are farther from Earth are also the younger we see (because light has taken millions of years more to come to us) and, as a consequence the more massive when we consider entire galaxies? (Because we cannot possibly see them as they are, but as they were millions of years ago.) Shouldn't we expect, correspondingly that the gravitational red shift of an observed galaxy will increase with its distance to Earth?
    Mohammad Ayaz Ahmad · University of Tabuk
    Jicai Pan, Subal Das Gupta, and Martin Grant , demonstrated a model, the disassembly of an excited nuclear system formed as a result of a heavy ion collision. We find that, as the beam energy in central collisions in varied, the dissociating system crosses a liquid-gas coexistence curve, resulting in a first-order phase transition. Accessible experimental signatures are identified: a peak in the specific heat, a power-law yield for composites, and a maximum in the second moment of the yield distribution.
  • Does someone have a protocol for home made Gibson assembly master mix?
    Gibson assembly is supposed to be seamless in cloning especially when you want to make a construct from different pieces (more than 2). Since the commercial kit from NEB is expensive, I would like to have my own home made kit.
    Terrens Saaki · University of Amsterdam
    I also want to mention that I designed primers that amplify the vector without extension. This comes handy when I want to use the same backbone for different reaction. Did someone find difficulties using this same strategy in Gibson Assembly?
  • William Mayor added an answer in Mind
    Why aren't scientists not successful in developing a science for consciousness?
    Do we reach God (here consciousness) through ‘gaps’ in the rules of nature or through the rules of nature.
    I might note that I believe most of us have a problem with knowledge regarding things "paranormal", especially as these pertain to consciousness. I know what I BELIEVE to be true, as I suspect most of us do, but belief is not knowledge. To make my point I will give a hypothetical situation where an individual has inadequate knowledge. This individual is setting out to establish that it can be predicted when water will boil. He sets up an experiment with what parameters he knows of. He sets up a test in Miami, FL, Denver, CO and Fairbanks AK. In each site he arranges for both indoor and outdoor testing. He uses the same quantity of water in every test and supplies the same amount of heat energy. He varies the size, shape and composition of the containers. He conducts a one test a month at every site for a year. Since he is unable to gain consistent results within the parameters he knows to apply, he concludes that water boiling is a paranormal event. Now who can argue with his logic without risking having that same argument used against their dismissal of other paranormal events?