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  • Hayder Obayes Hashim added an answer in Nanotubes:
    How to prepare Nanotubes and Nano particles powder for scanning electron microscopy

    Hello every one
    Recently in my lab, I'm working on scanning electron microscope (Quanta 450, FEI), i imaged many ready samples , but i have no idea how to prepare nanotube and nano particles powder for SEM imaging .
    please , I need any protocol or method to prepare nano powders for SEM .

    Regards ....

    Hayder Obayes Hashim

    Great answers thank you all .

  • Kåre Olaussen added an answer in Gravitational Field:
    Is the clock rate of free falling clocks the same?

    In a gravitational field of a homogeneous spherical mass M, a sufficiently small mass B, compared to M,  is left free in the gravitational field of M at a certain distance H from the center of mass, outside his surface. B gains speed, relative to the center of mass M, because of gravitational attraction. Many small objects like B free fall from different heights or from the same height at different instants.

    Every object has an atomic clock on board. Would these clocks have the same clock-rates during the free fall?

    A reference, master clock has to be adopted, otherwise the problem is ill posed. Clock-rates are refererred to an atomic clock on the surface of M for example (negligible M  rotation speed).

    The time elapsed for each body to go from the same starting and ending point counted by the atomic clocks on board is certainly the same (UFF).

    Their clock rate should be different, in general, unless they start from the same position and instant. Not because  light takes less time to reach the closest, since they are in different positions, but  because there exists a  relation between the very small object and the massive object.

    I would like your opinion regarding this problem.

    Kåre Olaussen

    Stefano> it does not make sense and could never been experimentally verified how the hits are viewed from the observer at rest

    Yes, "as seen"  is colloquial lingo, and must be interpreted "as seen by a theoretician using a particular coordinate system". A lot of statements in SR must be interpreted in that sense, including how an observer "sees" some events some distance away in his own rocket. There is only a quantitative difference between various observation-at-a-distance cases. However, the omnipotent theoretician can "see" everything from every coordinate system at her whims, and use that to deduce coordinate invariant predictions, like how many cycles an atomic clock has counted between two events through which it has passed.

    This distinction has not always been made. It is a commonplace to say that objects which moves very fast "looks" Lorentz contracted. Such that a very large and fast moving star far-far away, perfectly round, should "look" like very contracted elliptic disk. It was only 54 years after Einstein 1905 that James Terrell and Roger Penrose (independently) pointed out that the star would not look elliptic at all, it would still look like a perfectly round disk.

    This demonstrates a difference between "is seen" in a real experiment -- if performed,  and "as seen" (by a theoretician inspecting his coordinate systems).

  • David L Morgan added an answer in Research Papers:
    Is book review counted as a research paper if it is published in a research journal?

    I'm trying to write a book review for a research paper, all I want to know is that when it gets published in that research journal, will it be counted as a research paper or not? What weightage has it got? By the way, the research journal is a 'Z' category one according to the Higher Education Commission of Pakistan. Could anyone guide me in that regard please?

    David L Morgan

    In my university, it would not be counted as a peer-reviewed publication because it is solicited and evaluated solely by an editor. Hence, it would receive a relatively low weight in assessments.

  • Tho Thai added an answer in Protein Purification:
    How can I recover protein and resin?

    I'm trying to run a protein purification experiment using liquid chromatography. However, I forgot to remove DNA and other cellular debris from cell sonification before adding resin. What should I do to recover my protein with my resin?

    Tho Thai

    I used the Ni resin for His-tag purification

  • Joao Conrado Khouri Dos-Santos asked a question in Thrombin:
    Is it possible to prepare serum from platelet poor plasma, without using thrombin?

    I tried to incubate endothelial cells with platelet poor plasma (PPP) and coagulation ensued. So I would like to make the same incubation with serum, but I would like to obtain serum from PPP and not whole blood. Could anyone provide a protocol for obtaining serum from PPP or depleting coagulation factors from PPP, but not using thrombin?

  • Cyril Mechkov added an answer in Circuits:
    Who knows the properties and the working principle of this circuit?

    Recently I came across with the shown circuit.

    It has some interesting properties. Is there anybody who has used such a circuit already? Both opamps are assumed to be ideal.

    Cyril Mechkov

    Interesting thoughts, Lutz... With your enthusiasm you made me start thinking seriously about this "devilish" circuit:) ... but it takes time...

  • Suat Biçer added an answer in Vital Signs:
    Is capillary refill time a vital sign? or Why capillary refill time is not a vital sign?

    Capillary refill time is one of the sign of dehydration and shock. Capillary refill time is widely used by health care workers as part of the rapid cardiopulmonary assessment of critically ill children because it is a marker of increased peripherally vascular resistance. I think that capillary refill time is a vital sign. What is your opinion about this topic?

    Suat Biçer

    I am thankful for your response. I think that if new devices are used to detect the capillary refill time to provide more accurate measurements, it is more valuable physical sign and it may be considered as a vital sign. I am sending two articles about this topic as attachment.

    + 1 more attachment

  • Jakub Kuś added an answer in Social Media:
    Do you know any research about changes in perception of ethics and morality in the Internet?

    I'm looking for papers about changes in the morality and ethics which are caused by using the Internet. Do you know anything about that kind of impact? I found some really interesting papers, where authors prove that computer mediated communication may lead to much greater selfishness, relativism and treating others "less human". I'm looking for more results like this.

    I would be very grateful for any hint and answer.

    Jakub Kuś

    Thank you very much for all of your responses!

  • David L Morgan added an answer in Likert Scale:
    Is Coefficient Alpha Robust to Non-Normal Data?

    Dear researcher.

    Would you like to help me? I have a question about a reliability test with non normal data distribution.

    I have a data, N = 992, p values = 0.000 sig (Shapiro wilk / K-S). I use Likert scale, I use Cronbach Alpha to measure a reliability, and I use corrected item-total correlation for validity. But I have a doubt whether Is that a proper method or not.

    Thank you,

    Warmest regard.

    Nunix W. Frentyna

    David L Morgan

    Because Cronbach's alpha is based on the average of a set of Pearson's correlations, it will have the limitations due to non-normality that go with Pearson's. In essence, strong departures from normality "truncate" the maximum value of r that you are able to observe. Only when you meet the assumption of bi-variate normality is it possible to reach an r value of 1.0. But unless you have strong departures from normality, this is not likely to be a serious problem.

    Note, that if you are not using Pearson's r, you will not meet the assumptions that go with summing the variables to create a scale.

  • Lucio Munoz added an answer in Cold War:
    Thinking outside the box: Who will win the next cold war?

    There has been two paradigm shifts recently, one in the former red socialist countries, and one in the former pure capitalist countries, if you think outside the box these two shifts have the structures that  will be key to the future cold war....Has anybody thought about what this future paradigm clash structure is or will be? Has anybody wondered who will win the next cold war this time around and why?

    Lucio Munoz

    Dear Sankaran, two comments:

    a) the last cold war was a clash between a non-market system versus a market system; and paradigm death and shift expectations suggest the non-market paradigm will lose  as its economic sustainability gap will lead to its collapse in the long-term as no system can live under capitalism defictis for ever as the paper I shared above shows...and that is how the death of Karl Marx'w world happened.....in this type clash your observation is right the winnerr will the be one with capitlalism surplus/deeper pockets.....

    Adam Smith and Karl Marx Under the Sustainability Eye: Pointing Out and Comparing the Sustainability Gaps Behind these Two Great Simplification Failures.


    b) the future paradigm clash will be between two types of markets....the socio-economic market or red market versus the eco-economic market or green market....this time paradigm death and shift expectations suggest that other tings being equal it will be the environmental sustainability gap that will bring down the socio-economic system as you can not expand the socio-economy for every and live a constant accumulation of environmental sustainability deficits.....on the opposite side, it will be the social sustainability gap that will bring down the green market system as you can not forever accumulate social sustainability deficits....as the socio-economic system as you said see economic/industrial expansion as the fastes way to catch up in the market place its environmental sustainabililty gap will widen and make the system as a whole unstable......on the opposite side as the green market system sees eco-economic expansion as the way forward to leave every other system behind its social sustainability gap will widen and make the system as a whole increasingly unsustainablle....You see, the socio-economic system not easily will close the environmental sustainability gap and the eco-conomic system will not easily close the social sutainability gap......as both system are market systems you can assume equal capilalism footing/same economic power, then you see that the clash will be a clash between the environmental sustainability gap in the socio-economic system and the social sustainability gap in the eco-economic system.....under win-win situations, the one who closes the gap first wins so both would have an incentive to close it right away especially if the know the other is closing it, then the markets, socio-economic and eco-conomic would die and shift to sustainability markets....there would be only one global market then...same structure, no sustainability gaps.....Under no win-win situations we know from paradigm death and shift expectations that one system in conflict will collapse, but which, under which circunstances?....that is where thinking outside the box may help...to glance at the future....

    Have a nice day

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: Adam Smith stated the foundations of modern economics by simplifying reality dramatically in order to make development an economy only driven process. Karl Marx advanced the foundations of red socialism by simplifying really heavily too in order to state development as a society only driven model. And this set the stage for a long and well-known clash of paradigms, bare capitalism vrs red socialism. Surprisingly, their oversimplification of reality has led to paradigm death and paradigm shift in both cases almost around the same time because of the sustainability gaps they created. First the world of Karl Marx came crashing down when the Soviet Union fell apart in 1991 for avoiding to close its economic sustainability gap opening the doors for socio-economic models like that of China. Recently the model of Adam Smith, the traditional market, fell out of grace when the Bruntland commission called in 1987 for it to be fixed through sustainable development means to incorporate social and environmental concerns, opening the doors for eco-economic models or green economy market models as the one being championed today by international organizations and western countries and formalized in RIO 2012. Among the goals of this paper is to highlight the sustainability gaps that have led to demise of the world views of these two once great thinkers.
      Full-text · Article · Jan 2016
  • Sergei A. Ostroumov added an answer in Cryopreservation:
    Do you think that cryopreservation of frozen human bodies and their returning to life is possible?

    Some people hope it is possible. Some researchers think it is a kind of mission impossible. What do you think?

    Sergei A. Ostroumov

    Thank you all who answered.

    I have more questions. When water freezes, the volume of ice is more than the volume of water. It means that the frozen brain has a larger volume than the brain in its natural state. It means that the frozen brain will break the bones of cranium... What do you think?

    Perhaps there are no simple answers and there is plenty of room for variety in opinions... May I vote the answers of Mulyoto and Alexey up.

  • Abdul Ali added an answer in Supply Chain Management:
    What are the differences between Sustainable Supply Chain Management (SSCM) and Green Supply Chain Management (GSCM)?

    They are used interchangeably in various scholarly articles but i believe there are differences. I appreciate your comments.


    Abdul Ali

    Dear Muhammad Saad,

    I believe Green supply chain management do consider economic dimension of Tripple bottom line approach along with environmental consideration. 

  • Gilles Cuny added an answer in Cretaceous:
    Someone can help me to know what is this vertebra?

    Maybe is this a crocodylomorph vertebra? Thanks in advance.

    Fossil locality data: Barremian (Early Cretaceous) bonebed from alluvial-lacustrine deposits

    + 1 more attachment

    Gilles Cuny

    Well, from only a picture there is no way for me to be sure. I have seen some similar centra attributed to choristodere but...

  • Alexander B. Missyul’ added an answer in Molecular Crystals:
    Why is there no hysteresis in the solid-liquid phase transition?

    Most phase transitions in solids, like polymorphic solid-solid phase transitions, are slow and sluggish, showing a clear hysteresis effect. But when a crystal melts it seems to be a perfect first-order transition. Why is there no superheating in crystals and/or supercooling of the liquid melt? I am thinking primarily of organic molecular crystals here.

    Alexander B. Missyul’

    In fact, there is. Water, for example, can be supercooled down to −48 °C. From organics, glycerol is the most famous example of the easily supercooled compounds. Its melting point is 17.8 °C, but it almost never crystallizes at this temperature and it is possible to keep it liquid below −80 °C.

  • Wendell Orphe asked a question in pH:
    Can E.Coli and Salmonella grow in a same culture?

    When I grow them separately overnight  in Tryptic Soy Broth, then extract the DNA in a serial dilution I am able to get great ct values on qPR.  However, when I grow them in the same tube I am only able to get amplification on E.Coli.  I tested the pH of the TSB to make sure if there was any drop in pH but it read >6.5.  Are there any other inhibitors that will kill Salmonella?

  • Ximena María López Zieher asked a question in o Extraction:
    How can I preserve soil samples correctly for later RNA analysis? What RNA extraction kit o extraction protocol would you recommend for soil samples?

    I'm studying soil microbial communities response to nutrient addition and cattle grazing (cows) in the Pampean Region, Argentina. I'm doing DNA amplicon sequence analysis for bacterial and fungal diversity, but I'd also like to do bacterial RNA analysis to see changes in this group's functioning in soil.

  • Mingee Ong asked a question in Dissertations:
    Hi, would you guys be kind enough to help me fill up my dissertation questionnaire? Please your help is really needed ?

    Link is here below : 


  • Harry Friedmann added an answer in Philosophy of Mind:
    Schopenhauer, one of the greatest exponents of absolute irrationalism through asceticism, wonders: can knowledge guide the will that drives the world?

    Irrationalism is that way of thinking in opposition to the doctrines that relate to reason as the only instrument which, through distinctions, definitions and deductions, is able to give a coherent, clear and distinct vision of reality.

    At the end of the nineteenth century positivism and idealism were blamed for having formulated an abstract conception of reality as the result of a theoretical reflection that, based on the Absolute and scientistic fideism, ignored the reality of life.

    In particular, the irrationalism of Schopenhauer's thought is found in the theory of life as a blind manifestation of an arbitrary and alternative principle to reason: an irrepressible will to live, unbridled and irrational, that does not  pursue any phenomenal purpose other than to increase itself. The will to live produces pain but not for itself or for an evil connotation, because it is pure "noumenon". Pain, in fact, is born when the will to live objectifies in bodies that - wanting to live - express a continuing tension, never satisfied, to that life which appears to them as always missing than they would like. The more you have lust for life, the more is the suffering.

    "We delude ourselves constantly that the desired object can put an end to our will. Instead, the object wanted assumes, just when it has been reached, another form and under it reoccurs. It is true that the devil always teases us in new forms. "

    The will, being irrational and blind, cancels any worldview as ideologically organized. Order and harmony give way to madness, irrationality and instincts dictated by the will which is the essence, the thing itself to everyone.

    However, in contradiction with the inscrutable and inevitable character of its irrationality, from that there would be no way out without recognizing to man any chance of conscious choice, Schopenhauer asks man a rational and moral task of liberation from that there would be no way out without recognizing to man any chance of conscious choice, Schopenhauer asks man a rational and moral task of liberation from pain through self-denial of the will to live: asceticism.

    "The identity of the subject of knowledge and that of the will appear here as a prodigy. In fact, can you never know the will? Can the will do that will? On the other hand, knowledge can guide the will, which is what drives, what creates the world? » Schopenhauer asks man a rational and moral task of liberation from pain through self-denial of the will to live: asceticism. "The identity of the subject of knowledge and that of the will appears here as a prodigy. In fact, you never know the will? Can the will do other than to will? On the other hand, can knowledge guide the will, which is what drives, what creates the world? »

    Schopenhauer therefore, arguing that "only the elimination of the will of life in general can free us," not completely devalues the role of reason, conceived as a platonic expression of life itself that wants to know becoming self-conscious". The will is the thing itself of Kant; and Plato's idea is fully adequate and exhaustive knowledge of the thing itself, is the will as an object. "

    This awareness coincides with the self-denial of the will, and thus allows to leave the senseless cycle of desire, death and rebirth.

    Therefore, in relation to the above, there is to consider that the absolute irrationalism concerns teachings which insist on the absurd, senseless, without any purpose of reality.

    Of this current an outstanding representative is Schopenhauer who considers nature, man, history ruled by a blind desire that haunts all creatures and unleashes a brutal, senseless, perennial and universal conflict. Also Schelling and Kirkegaard fight in the name of irrational instances, the ‘panlogism’ and the absolute reason of Hegel. Recently, irrationalism has reappeared with existentialism, a theme used by both the Nazis and fascism, as well as the Frankfurt School. The modern irrationalism seems lead to a radical awareness of the historical and theoretical limits of the Western ‘ratio’.

    Harry Friedmann

    Under the influence of the Upanishads and Buddhism, Schopenhauer probably had in mind the liberation from the world of af appearences considered as vanity of vanities (Ecclesiastes) or as Karma,, Samsara and the veil of Maya. He certainly did not intend to deny the formless Dharma. In Nietzche's words: Der Mensch will lieber das Nichts wollen als nicht zu wollen.

  • Veronika Svachova added an answer in THP-1:
    Do you have some experience with cultivation THP-1 in IMDM?

    I know, that the best choice for this is RPMI-1640 but I need to prepare co-cultivation experiments with cells line of renal epithelial cells. In our protocol I use IMDM for cells of renal epithelium. When I added IMDM to THP-1, they adhered. Is it normal? Thanks for you help!

    Veronika Svachova
    Thank you so much for your answers. I tried experiment again with new bottle of IMDM and THP-1 cells were fine. Probably our medium was contaminated.
  • Gesmar Santos added an answer in Sustainable Agriculture:
    How developing countries can achieve a high market share of capital goods and services related to them?

    I intend to study the limits and possibilities of access for developing countries to add value, production of capital goods and services from leading emerging markets. For example, sustainable agriculture and renewable energy.

    Gesmar Santos

    Dear Oscar,

    Thank You for answer.  I think You are right about tourism and sustainable farms. But, on the other hand, developing countries will keep their dependence on capital goods.

  • David Bolton added an answer in Process Modeling:
    Is there any heater AND cooler flexible elements for pipes ?

    I want to perform cycle studies on an existing system. So I need to modify some existing pipes to control the temperature.

    Do you know if heater and cooler in one piece jacket exists ? Like something containing heating wires and cooling Peltier elements ?

    Or if you have any suggestion, I'm listening

    David Bolton

    Okay. I guess you might have a solution by now, but if not...

    How about using small diameter copper tubing (maybe 4mm outside diameter) which you wind around your column (alongside your heating wire).  You can cool the tubing by bleeding compressed air into one end (via a small adjustable throttle valve), allowing the cold expanded air to pass along the tube and out of the open end.

    If you need to automate the cooling, you can use a solenoid valve ahead of the throttle valve.

    Depending on how long you need to run the system, you might even be able to use a compressed nitrogen cylinder as your gas source.  This would have the advantage of using a gas that was already dry, so there would be no chance of moisture freezing in the throttle valve. However, it would be perfectly feasible to run such a system from a small air compressor - with a desiccant canister in the line to remove moisture.  And as your lowest temperature is 5 C then you may not get freezing in the valve anyway, without having to dry the air.

    Similar systems are sometimes used to cool instruments that have to operate at low temperatures (e.g. infra-red cameras).

  • Khagendra Raj Baral added an answer in Anaerobic Digestion:
    Is relative gas diffusivity changed after liquid manure application?

    Any one can suggest how the relative gas diffusivity changes after liquid pig manure (slurry), cattle slurry and anaerobic digested applied in a sandy loam soil?

    Khagendra Raj Baral

    Thanks Susantha ! Do you have any suggested literature for me? please share if you have.

  • John D Elsworth added an answer in Neuroscience:
    How long will be post fixed with FA4% the whole rat brain ?

    I post fixed rat brains in a 4% formaldehyde solution (10X the volume of the brain) but I don't know the optimal time for this fixation step.

    John D Elsworth

    In addition to the antigen being targeted and ratio of tissue to fixative solution being used, important variables are the thickness of the tissue being fixed and the temperature at which the fixation is carried out. Bear in mind that the center of the tissue will take considerably longer to fix than tissue nearer the surface. About 24 hrs in 4% formaldehyde solution (aka paraformaldehyde solution) (same as 10% formalin) is a common time for fixing a rat brain.

  • Oscar May Tzuc added an answer in Computational Fluid Dynamics:
    Wich is the best software to realize Computational fluid dynamics (CFD)?

    I need start to realize computational fluid dynamics but  I dont know wich will be the best software to begin. Doing a quickly search on internet I have found some software like Autodesk and SolidWork but I would like to know if exist any more specialized or which one is better, Thank you. 

    Oscar May Tzuc

    I am truly greatful for yours anwers wich have helped me to clear several doubts. Now I have an idea about the diference of the diferents softwares and could gide by the best way my work.

    Thak you. 

  • Giuseppe Cotellessa added an answer in Spinal Injuries:
    Could be welded neurons togheter to repair spinal injuries?

    Broken neuronal connections are the cause of paralysis, organ failure, and other serious conditions. There have been attempts to bypass such injuries, with limited success, but now researchers at the University of Alberta in Canada have developed a technique that uses lasers to essentially weld neurons together. There’s still a ways to go in using the technology in clinical applications, but the breakthrough is certainly very promising for treating chronic disabilities and various debilitating conditions.

    Giuseppe Cotellessa

    I thank Vladimir A. Kulchitsky for his vote up and for his useful answer.

    Best regards.

    Giuseppe Cotellessa

  • Khalid Hassan added an answer in Fitness:
    What is your definition of 'fitness'?

    It's all in the question


    Khalid Hassan

    Dear Marcel
    Fitness represent the relative contribution of certain genotype in the next generation ,hence the good genotype has high fitness ( good viability and high fertility ) and contribute with high percentage of progeny in the next generation and as a result be the norm phenotype in the population.
    While low fitness genotype ( low viability and poor fertility or may be sterility ) and contribute with low percentage ( or may be not contribute ) in the offspring of the next generation, so this genotype will be rare and represent the abnormal in the population.

    Fitness represent the action of natural selection which drive the evolution and development.

    All characteristics deal with fitness but in different degree .
    Good Luck

  • Somayeh Sohrabi added an answer in Cations:
    Hi everybody, Can anyone introduce me a scientific database containing the ionic radius of cations?

    Especially, Ti4+, Fe3+,Cu2+

    Somayeh Sohrabi

    Dear Michael,

    Thanks a lot , I have seen this database in advance, but I am not sure about its accuracy. in addition, it does not provide the value for Ti4+. However, in case of different charges of ions and their coordination, the data are sufficient.

    Best regards,

  • Dan S Correnti added an answer in Quantum Mechanics:
    Help with Feynman's(thought) experiment with electrons?

    I read his description of the experiment but I still haven't understood as to how the results can't be predicted with "classical physics", what I mean is that electron gun which he has assumed throws out electrons randomly and since we do not know the initial conditions( because of randomness) we can't predict the exact trajectory , and therefore we can talk  only of probability, but I see that Feynman says constantly that "we can't really predict where the electron would end up being" but ain't that because of the random nature of electron emitting device??

    Obviously i am wrong somewhere but I can't catch it?

    Any help would be appreciated.

    Now Feynman has constantly  

    Dan S Correnti

    A practical consideration regarding the Huygens-Fresnel principle:    If we assume that a light wave can interfere with itself,  then we should be able to see an interference pattern of photon hits on the detection screen without the presence of the intermediate plate that contains the single or double slit(s) used in single or double slit experiments.  But, we know this doesn’t happen;  for example, slit(s) are required in order to get a diffraction pattern of interference bands on the detection screen.

  • David L Morgan added an answer in Survey Methods:
    Can independent continuous variable be used along with manipulated categorical variables in an experimental design?

    I have some doubts regarding designing an experiment with manipulated and un-manipulated independent variables. I would be grateful to get your inputs and suggestions.

    I am using  an experimental vignette survey method, using a 2 * 2 between subjects design. There are three independent variables out of which two are being manipulated and are categorical variables. The third independent variables is a continuous variable which I am measuring through items based on a description in the questionnaire. There are four versions of the questionnaire based on the two manipulated variables. All are measuring the same independent variable (based on the same description in all versions) along with the dependent variable.

    The independent continuous variable is of primary interest for the research.The focus is on finding the impact of the manipulated variables on the relation between independent and dependent variable.

    Can I use such a design?

    I have not come across any papers which use a similar design. It would be great if you can refer some similar papers and give your feedback,

    Many Thanks


    David L Morgan

    I agree with Stephan that Analysis of Covariance would be a standard technique for considering the impact of a continuous independent variable that is not part of the experimental design itself.