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  • Eric Lord added an answer in Special Relativity:
    Is a rigid rod moving perpendicularly to x axis (in the standard Special Relativity axes convention) parallel to the moving system x’ axis?

    I had a few discussions of this problem and most people maintain the moving rigid rod always parallel to x is not parallel to x’ even though it is said x' axis is co-linear with x axis which is counterintuitive.

    I maintain that parallelism is preserved by the assertion of possible coincidence and co-linearity of the rod with x axis which is co-linear with x' while the STR formulae after Lorentz transformation seem to indicate otherwise.

    Any thoughts/comments/discussion in that matter will be highly appreciated as they are vital to my research.

    Eric Lord · Indian Institute of Science

    Dear Johan ~

    Two perfect identical clocks that register the same time when the are together at the spatial origin O (x, y, z) = (0, 0, 0) then move around and again come together at O. Your hypothesis is that they will still register the same time. That is a hypothesis that you assert without proof. It's not logically necessary. As you know, the majority of physicists and mathematicians are not paying attention to you. You can’t expect them to reject SR (which, so far as the are concerned, is logically consistent and consistent with experimental evidence) unless and until you can offer them mathematical proof or experimental support for the hypothesis.

  • Petr Viscor added an answer in Electrochemistry:
    Does gold sputtering in electrolyte samples (disc-shaped) interfere during AC conductivity measurements?
    I used gold sputtering (to make electrode contacts) in Ca doped LaInO3 samples for AC conductivity measurement from room temperature to 800C. Does it interfere with the conductivity response of my sample?
    Petr Viscor · EIS Laboratory

    I do not know what LaInO3 samples are like (insulator, semiconductor ?..). I agree with Jea that Cr adhesion layer before Au layer is a good thing (It works on sapphire, silica glas, Si monocrystal (doped, undoped). In all these case , the electrode geometry is well defined.

    Multilayer metal electrode systems can be considered in most cases as a single metal layer, so in this respect, there is no problem in standard Electrical Impedance Spectroscopy experiment. However, it might be that the Cr layer might alter the electrochemical potential of pure gold layer facing your sample, in which case your depletion/accumulation layer (if present) will be altered. The amount will depend on the difference in the respective electrochemical potentials (elchpot of Cr/Au and elchpot of your sample). My gues is that this difference is about  few tenths of eV (~0.1-0.2 eV). The best way is :

    1. To measure the impedance for your system with two different thicknesses (doubling the thickness will double the low frequency real part of impedance, while halving the real part of the measured capacitance) If this is all you see, then you are not measuring sample-electrode interface and there is no problem.

    2. If 1. is false, the low frequencies should reveal your metal electrode-system interface and in this region of frequencies you should see whether Cr adhesion layer affects this part of the impedance sopectra.

    With regards


  • Anuradha Potlapalli added an answer in Cooling:
    What is the criterion that allows us to judge whether a draft of atmospheric water extraction is profitable or not?
    Moreover, last year, I supervised a group of engineers in a project that involves the extraction of atmospheric water by condensation of moisture. In this study we seek with outillage of practical work for the air conditioning calculating the amount of water extracted according to several parameters, but much remains to be done.
    Anuradha Potlapalli · Poornima Group of Colleges

    profitability of this process depends on the cost of manufacturing ,time and technology required.it also depends on the environmental impact whether positive or negative the entire process is causing.

  • Mohamed Hassan Abukashawa added an answer in NGOs:
    Can anybody recommend literature that is available online about the importance of public relations to NGOs?
    Mohamed Hassan Abukashawa · Rakaiz for researches and studies

    you may see IPRA wep site

  • How can we derive real parameters with physical meaning from imaginary data using electrochemical impedance spectroscopy?

    I always use electrochemical impedance spectroscopy in my studies. In nyquist plot one axis is imaginary part. If we don't use it we couldn't calculate the physical parameters such as double layer capacitance, charge transfer resistance etc. but imaginary part doesn't have physical meaning and we use it to calculate physical parameters! how can I explain this for someone who doesn't know about impedance nevertheless he is a professional physicist?

    Ahmad Sharifi-viand · Khaje Nasir Toosi University of Technology

    Thank you for your answer dear Dr. Petr Viscor. i wish you add more explanation so that i can satisfy a professional physicist.

  • Edward Alain Pajarillo asked a question in JavaScript:
    What is the best programming language to focus and study for Bioinformatics?

    I am very interested in studying programming on my own, but I don't know what should I focus on is it C+++, Javascript, R, Python, Perl, Ruby? And can you recommend specific steps on how to study programming from scratch?

  • Jethro Betcke added an answer in Solar Energy:
    How does the solar energy work?
    • How does it work?
    • Is it the solution for decrease the expense?
    • Is there a better system of generating energy that is cheap?
    • Discuss that please.
    Jethro Betcke · Carl von Ossietzky Universität Oldenburg

    Dear Marcelo,

    Your question is very general, and to be a bit blunt, sounds like: "please do my homework for me". There are many introductory texts on solar energy, both on the web and in the form of books. I recommend you start with that.

  • Mohamed Hassan Abukashawa added an answer in Sudan:
    Can producers use social media to raise awareness about food products for consumers in developing countries ?

    People in Sudan for example are Whatsup addicts can their addiction be shifted to a positive trend 

    Mohamed Hassan Abukashawa · Rakaiz for researches and studies

    it will be effective from my point of view, because new media has a wide range and it exceed the traditional media now a days  

  • Alireza Rahmani asked a question in Image Processing:
    What are the methods for hand detection and tracking?

    We would like methods that performed with using image processing.

    Please if you know special reference, introduce to us.

  • Ines Ghali added an answer in Bacterial Cells:
    Should we use SDS and chloroform together in Bacterial Cell permeabilization?

    I want to do cell permeabilization for bacteria and almost all the papers I checked so far used chloroform and SDS combined.

    I want to know if one of them alone can be used (SDS or Chloroform)?

    If not what is the role of the chloroform in the permeabilization process?

    Thank you.

    Ines Ghali · National Institute of Livestock and Grassland Science

    Patrick and Avijit , Thank you very much , it was really helpfull 

  • Jochen Wilhelm added an answer in Variability:
    In Regression analysis the Rsquare represents?

    I have calculated relation between dependent variable and independent variable using the Regression analysis.

    Jochen Wilhelm · Justus-Liebig-Universität Gießen

    R² = the proportion (fraction) of the total variance that is "explained" by the regression model.

    The variance of the data is the average squared distance of the values to their mean.

    Applying a regression model means that the "mean" (=the model prediction) will depend on some predictors(s). The distances to these "means" are called residuals, and the average suqared residuals is the residual variance.

    The residual variance (against the model predictions) will always be smaller than the variance (against a constant mean value). This reduction in the variance is said to be "explained" by the model, and R² is this reduction relative to (=divided by) the variance.


    x = 1,2,3,4
    y = 2,5,6,9

    variance = 8.333*

    linear regression model: y = 2.2*x + 0.0
    predicted values = 2.2, 4.4, 6.6, 8.8
    residuals = -0.2, 0.6, -0.6, 0.2

    residual variance = 0.267

    reduction in variance due to the model = 8.333 - 0.267 = 8.067

    R² = 8.067 / 8.333 = 0.986

    * the variance shown is the "sample variance" (what is usually reported as "variance" by most software), that is the sum of the squared diveiations divided by n-1 (here: 4-1=3), and not by n. This denominator is the calculated in the same way for the residual variance. Therefore this denominator will cancel out in the calculation of R² anyway and it does not matter what kind of variance (sample or population variance) is used. One could thus say that R² is the reduction in the "sum of squared deviation" explained by the model relative to the "sum of squared deviations" of the data.

  • Is there a definition of the Mittag-leffler function for variable-order fractional calculus?
    E_q(t) with q a bounded function.
    Hammouch Zakia · FSTE Université Moulay Ismail

    Dear Professor  R.Heremann,

    Thank you !

  • Kamal Eddin Bani-Hani added an answer in Academic:
    Could you please name necessary steps for developing a more innovative organization?

    Academic knowledge and managerial experience is first built on what others have said, done or written. What are the capabilities organizations must develop
    if they want to grow and compete in innovation-intensive environments. 

    Kamal Eddin Bani-Hani · Hashemite University

    Implement a policy of "Brain Gain"!!!!!!!!!

  • Jan Szulejko added an answer in Global Warming:
    Will recent warming hiatus with respect to mean temperature continue or not?

    2014 became the warmest year on record, without a strong El Niño. The so-called global warming hiatus (1998-2012) are widely concerned. In the following decade, global mean temperature warming will continue to slow down, or will rise much more rapidly than in the "slowdown" period? What are main physical causes responsible for inter-decadal changes of mean temperature?

    Jan Szulejko · Hanyang University

    Alastair Bain McDonald

    Thank you for your comments on Scafetta's  ‘Empirical Evidence for a Celestial Origin of the Climate Oscillations and Its Implications’.

    I analysed the NOAA 1880 - 2014 global temperature anomaly (GTA) data by fitting it to a linear function and a cosine function in MS-XL by "eyeballing". Later, I found a similar analysis in the literature. My "eyeballed" fitting is reasonable. The results I obtained were:

    (a) linear part .... 0.6 C rise per century. The global temperature anomaly (GTA)  has been increasing at this rate since the Little Ice Age. irrespective of the ever increasing anthropogenic fossil fuel CO2 emissions.

    (b) cosine part: amplitude = 0.2 C and period = 61 years. The amplitude = 0.2 C is in excellent with Scafetta's finding of "variation in global surface temperature (GST) over a range of 0.4C". This accounts for most of the GTA increase during the 1970 - 2000 period. Afterwards, there will a slight global cooling trend to about 2030 and global warming will resume in earnest based on empirical analysis.

    Taking points (a) and (b) and the ever increasing CO2 levels of recent  together, leads to your point

    "... but 2014 was the warmest year on record. So it seems that the CO2 now overrides the Scafetta effect, and when it begins again to reinforce the CO2 effect we will be in deep trouble, especially since by that time the CO2 concentration will be even higher than it is today! "



  • Mario Paschoal added an answer in Exercise:
    Are there some article to learn how change the VO2 kinetics with exercise?

    I want to learn how observe changes in VO2 kinetics during exercise and how extract dates.

    Mario Paschoal · Pontifícia Universidade Católica de Campinas (PUC-Campinas)

    The kinetics of VO2 it is a term that explains how behaves oxygen consumption in dynamic terms while performing a physical effort. It is usually measured during incremental exercise, and all aerobic-anaerobic training interferes with their dynamics. Therefore, there are numerous articles dealing with this term and this line of research, just look for the term kinetics of VO2 you will find many that interest you. Good luck!

  • Anuradha Potlapalli added an answer in Invention:
    What can be done to motivate more women to invent and claim patents for their inventions?

    In their book "The Invisible Edge: Taking Your Strategy to the Next Level Using Intellectual Property" Mark Blaxill and Ralph Eckardt  describe the economic and strategic value of patents.Why are women so underrepresented among inventors and what can be done to improve the situation?

    Hunt, J., Garant, J.-P., Herman, H., & Munroe, D. J. 2012. Why don't women patent?: National Bureau of Economic Research.

    Busolt, U., & Kugele, K. 2009. The gender innovation and research productivity gap in Europe. International Journal of Innovation and Sustainable Development, 4(2): 109-122.

    Anuradha Potlapalli · Poornima Group of Colleges


  • Peter T Breuer added an answer in Number Theory:
    Is there any possibility for the sumset of two sets of integers, which are not arithmetic progressions, to be an arithmetic progression?

    The notion of sumset of two sets is defined as A+B={a+b:a in A, b in B}. If the elements of A and B are not in AP,  then can the elements of A+B be an arithmetic progression? If so, what are the conditions required for that? Please suggest me some good references...

    Thanking you in advance,

    Sudev Naduvath

    Peter T Breuer · Birmingham City University

    Alex, the point is that the incremental interval beween elements is 1. Your answer instead seems to show a geometric series with ratio 2.

  • Sudev Naduvath added an answer in Percolation:
    Can anyone suggest a good book, tutorial, or papers on Percolation Theory?
    In mathematics, percolation theory describes the behavior of connected clusters in a random graph. I would like know this theory in detail.
    Sudev Naduvath · Vidya Academy of Science & Technology

    Please see the following books.

    1. Applications of Percolation Theory - Shimi & Shini, Pub: CRC Press.

    2. Introduction to percolation Theory - Stauffer and Aharoni , Pub: Taylor & Francis

    3.  Percolation Theory for Mathematics - Hary Kesten, Pub: Birkhäuser Boston

    4. Physics and Geometry of Disorder: Percolation Theory - A. L. Efrose, Pub: Mir

  • PCR product clonning with the TOPO XL PCR Cloning Kit?


    I am trying to clone a long PCR product with the TOPO XL PCR Cloning Kit. I have made all the process according to manufacturer's instructions, but I am having some problems. When I make a PCR with my specific primers to confirm the cloning process, I see in the agarose gel lots of inespecific PCR produts, none of then corresponding to the PCR product I had intentions to clone.

    I suppose that the problem is in the cloning reaction.

    Can anyone give me some advice of how the proceed to successfully clone the fragment?

    Thank you in advance.

    David Fernandez-Antoran · University of Cambridge

    Hi Ana,

    Have you tried to digest the plasmid (once has been ligated and transformed into bacteria) with different restriction enzymes to see whether you have cloned correctly?. Sometimes PCR gives you wrong results because of primers efficiency and amount of plasmid DNA. But restriction analysis is very strong.

  • I am looking for scholarly literature on war journalists from developing countries. Can someone help and recommend some work ?

    My readings for the past one year has revealed that war journalism is a predominantly western based. But have the developing world indulged in studying their journalists' who cover wars

    Mohamed Hassan Abukashawa · Rakaiz for researches and studies

    u are most well come Pushpa

  • Miranda Yeoh added an answer in Social Epidemiology:
    Why social inequality persists?

    “Beliefs which serve privilege, elitism and inequality infect our minds
    like computer viruses. But now Dorling provides the brain-cleaning software we need to begin creating a happier society.”
    Richard Wilkinson, Emeritus Professor of Social Epidemiology and au-
    thor of The Spirit Level

    Miranda Yeoh · Kolej Matrikulasi Selangor, MALAYSIA (Selangor Matriculation College)

    @Amir, at the level of the individual in society, poverty and inequality are due to:

    1. unemployment or having a poor quality (i.e. low paid or precarious) job as this limits access to a decent income and cuts people off from social networks;
    2. low levels of education and skills because this limits people’s ability to access decent jobs to develop themselves and participate fully in society;
    3. the size and type of family i.e. large families and lone parent families tend to be at greater risk of poverty because they have higher costs, lower incomes and more difficulty in gaining well paid employment;
    4. gender - women are generally at higher risk of poverty than men as they are less likely to be in paid employment, tend to have lower pensions, are more involved in unpaid caring responsibilities and when they are in work, are frequently paid less ;
    5. disability or ill-health because this limits ability to access employment and also leads to increased day to day costs;
    6. being a member of minority ethnic groups such as immigrants/undocumented migrants as they suffer particularly from discrimination and racism and thus have less chance to access employment, often are forced to live in worse physical environments and have poorer access to essential services;
    7. living in a remote or very disadvantaged community where access to services is worse.
  • Which key performance indicators can be used to measure effectiveness of digital marketing activities on financial performance of a business?

    I am looking for significant key performance indicators to measure digital marketing activities through which we can see financial impacts of these communication channels on business growth.

    Ilaria Barletta · Chalmers University of Technology

    According to a document issue by the Nielsen Company "Beyond Clicks and Impressions: Examining the Relationship Between Online Advertising and
    Brand Building"  there is no statistical correlation between the Click-Through rate (CTR) and the sales lift. However, generally speaking, you could look at ad recall metrics and click stream analysis to see if they embed ways to measure the impact of digital marketing on economics.

  • Ewen A Griffiths asked a question in Fundoplication:
    What is the difference between a Lind and Toupet fundoplication?

    Is it just a Lind is 300 degrees and a Toupet 270 degrees or are there other technical modifications to the posterior partial wraps ?  

  • Can any one provide the literature available on the biological treatment of leather industry wastewater?

    Leather industry are the key contributors to the economy of developing nations, however, unfortunately are the major polluters because of its toxic nature of wastewater. Physical and chemical treatment processes, which are used for the treatment of wastewater are not environmental friendly. Therefore, the biological treatment processes should be applied for the treatment of leather industry wastewater.

    Adeyemi S. Adeleye · University of California, Santa Barbara

    Hi Gauraz,

    Here are some links to the literature on biological treatment of leather industry waste. Hope you find them helpful:




  • Abdul Jabbar Khan added an answer in Dilatation:
    What's the influence of the dilation angle on the drained bearing capacity of shallow foundation?

    I know, when the dilation angle less than the friction angle, the bearing capacity is lower than the dilation angle = friction angle.
    i want more notions for this case (behavior of the soil) .

    Abdul Jabbar Khan · Bangladesh University of Engineering and Technology

    I will try to upload a write up of mine soon.

  • Debasish Pradhan added an answer in Plant Extracts:
    How we can identified the compounds present in plant extracts without using chromatographic and spectroscopic methods?

    Plant is a rich source of phytochemicals. How we can identified the compounds present in plant extract without using chromatographic and spectroscopic methods? 

    Debasish Pradhan · Utkal University

    I agree with Dr Ellen Simms

  • Jayson Enciso asked a question in Species:
    Can anyone identify the Scientific Name of this species?

    This plant is not yet identify the scientific name. I want to know this for DNA Bar coding study. Thank you.

  • Ger Koper asked a question in Interfacial Science:
    Interested in courses on Interfacial Engineering and Fluid Mechanics?

    Then the upcoming COST Action CM1101 Training School on "Interfacial Science and Fluid Mechanics: Fundamentals, Applications, and Analytical Methods" in London may be worth looking at, see cost2015.stfca.nl

  • Lauric Henneton added an answer in Protestantism:
    How acceptable was it for Catholics (lay or not) to attend Protestant services in the 17C?

    The context is a diplomatic visit. One (lay) Catholic was trying to get assistance from devout Protestants and attended their church services. His (Catholic) rival sent a delegation of clerics who chose not to attend those services. Canadian Jesuit historian Couillard-Desprès, in the early 20C claims that according to Catholic doctrine, Catholics who attended Protestant services, especially when they sort of had to, were not running the risk of being considered sinners, let alone apostates. Couillard-Desprès doesn't give any evidence supporting his claim. Would anyone have references to suggest supporting his claim? Many thanks.

    Lauric Henneton · Université de Versailles Saint-Quentin

    Thanks to all for the great feedback, I didn't get notifications so I'm checking out only a bit late. The French layman visited Boston in 1643 and the Capuchins sent by his rival visited in 1644 and 1646. A revised version of the article is under review and should appear later this year. Not sure I can disclose more at this stage but I'll certainly add it to my publications here and on Academia.edu.

    Thanks again to one and all!