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  • Marian Evans asked a question in Beekeeping:
    Is anyone researching beekeeping in Africa please, in Nigeria in particular?

    I am researching beekeeping and bee nutrition within a community context.

  • Isaac Sánchez-Juárez asked a question in Publication:
    Does anyone have information on the relationship between public debt, public investment and economic growth?

    Please!, I need papers that studied the relation between the public debt, public investment and economic growth, mainly in the subnational case.

  • Alice Jones added an answer in LGM:
    Past sea level data back to the LGM?

    Does anyone know any sources of sea-level time series data back to the last glacial maxima? My study region is Indonesia, but I assume that there are unlikley to be regionally resolved data available...... Any hints would be gratefully recieved.

    Alice Jones · University of Adelaide

    Thanks very much Sergei.

  • How far can one get with analogies in theoretical physics?

    Many a great theoretical physicist have gone on to explain their work qualitatively to the public, often times by virtue of analogies.

    Now, I know analogies and qualitative explanations can be misleading if not presented correctly. Having a little background in mathematics (basic ideas in tensor descriptions of space-time etc.) I realize some of these analogies presented to me in the past are very misleading, while others are almost as good as a conceptual "one-to-one mapping" (so that understanding of the analogy leads to an almost perfect understanding of the concept)... almost as if the analogy belongs to the same abstract category as the concept to be explained.

    I would just like to know (though I guess there is no exact answer): how far can one get to a full understanding of theoretical topics with qualitative explanations. Or, on a more pessimistic note: is it worth explaining things like general relativity, quantum mechanics, and string theory qualitatively and by analogy for any other purposes than "sensational" science?

    Michael Crescimanno · Youngstown State University

    [4]  arXiv:1504.06401 [pdf]The Benefit of Seeking a General Rule for Learning from Analogy
    Eric Kuo, Carl E. Wieman
    Subjects: Physics Education (physics.ed-ph)
    It is common practice to teach physical concepts with an analogy. However, how such analogical instruction should be structured is not well studied. We compare two ways of using an analogy to learn a target physical principle: (i) applying the analogy to the target physical context on a Case-by-Case basis or (ii) using the analogy to create a General Rule in the target physical context. In the discussion sections of a large, introductory physics course (N = 231), students who sought a General Rule were better able to discover and apply a correct physics principle, gaining 15% more than Case-by-Case students from pre-test to a mid-test immediately after the discussion section. Later, both groups gained the same amount from subsequent direct instruction on that principle. The explanation is that students who performed Case-by-Case analyses are more likely to focus on idiosyncratic problem-specific features rather than the deep structural features that can be used to answer such problems in general.

  • Chris Sharples added an answer in Bathymetry:
    What are the best ways to determine sand movement patterns and volumes in the intertidal and subtidal areas adjacent beaches?

    I am wanting to get some empirical measure of sand transport patterns, directions and volumes into, within and out of a particular beach embayment, and am wondering what is the current state of the art in this area? (e.g., tracer particles, high-resolution bathymetry for interpretation of bedforms indicative of currents transporting sand, etc?)

    Chris Sharples · University of Tasmania

     Thanks Pradeep, I have read the abstract which looks potentially useful to me.  Do you have a PDF copy of the full paper that you could send me?

  • Richard M Higashi added an answer in LC-MS:
    What are the opinions on working with metabolomics in blood cells?

    Dear All

    I wish to work on metabolomics aspects of different blood cells using LC-MS. I would appreciate if anyone can help me providing interesting references regarding sample preparation and sample analysis and data analysis.

    Richard M Higashi · University of Kentucky

    Blood cells have extremely high protein content and standard extraction methods don't work.  Should contact someone like Dr. Roback to get advice.  Also there are no "canned" methods for metabolomics, so generic answers w/o understanding the experimental design & goal first, should be avoided.

  • Muhammad Fuady Emzir added an answer in Gaussian:
    Is there a generic expression to represent the multiplication of a distribution ?

    Let say a value N >> 1 is distributed among m>1 members, which can follow some distribution (Binomial or Gaussian). Is there any generic term to represent the multiplication of the distribution. For example, a silly guess for multiplication of uniform distribution will be (N/m)^m. Is there any generic term for other distributions too? 

    Muhammad Fuady Emzir · University of New South Wales

    I think the clue is to use the characteristic function of N. Suppose now, N = x1+..+xn. Where {xi} is independent identical random variable with Gaussian distribution. Then The characteristic function of N can be computed from E(exp(i t N)).  You can also compute the distribution of P = x1*x2*...*xm in a similar way. If you get the characteristic function of N or P, then a Fourier transform of it will be the desired probability density function.
    For more information, see http://en.wikipedia.org/wiki/Characteristic_function_%28probability_theory%29.

  • Narsimha Garlapati added an answer in ENVI:
    Has someone compared the ENVI LiDAR , LP360 and LAS tools?

    I'm interested in knowing the best and most user friendly LiDAR processing softwares to deal with both the discrete and full-wave form data.

    Hope someone may already have investigated in this topic and your feedback would be much crucial for me.



    Narsimha Garlapati · Australian National University

    Hello Mustak,

    I would like to map the fuel loads (understory & ground ) and structures for the bushfire project. In the coming few months I shall receive the full wave form LiDAR data from the project stakeholders, so right now I'm investigating the best tools that are available for this purpose.



  • Leroy Mason added an answer in References:
    In AI, how do I formally define the difference between a "theory" and a "model"?

    In AI, does anyone know of the formal definitions for "theory" and a "model", and a specific references?

    Leroy Mason · University of New South Wales

    you're probably right - are there any good online sources for epistemology? The problem with search for "model" and "theory" is that too many non-relevant hits are returned.

    I think this is OK for "model" from Section 1 of http://plato.stanford.edu/entries/model-theory/ but what about "theory"? Is a theory equivalent to a first order logic program?

    Sometimes we write or speak a sentence S that expresses nothing either true or false, because some crucial information is missing about what the words mean. If we go on to add this information, so that S comes to express a true or false statement, we are said to interpret S, and the added information is called an interpretation of S. If the interpretation I happens to make S state something true, we say that I is a model of S, or that I satisfies S, in symbols ‘I ⊨ S’.

  • Son The Le added an answer in Silver Nitrate:
    What is the mechanism of electroless plating of SIlver on a Silica surface?

    A Silver shell can be reduced from silver nitrate onto a negatively charged surface using Butlyamine, what I'd like to know is exactly what's happening in the reaction. Thanks in advance for anyone that answers

    Son The Le · Korea Institute of Science and Technology

    I think it's possible because in ethanol, -NH2 is also deprotonated. I don't know exactly what is the different between ethanol and basic environment but actually, it's seems to be both ethanol and basic pH to deprotonate -NH2.

    One more thing, from my experience, somehow the silver nanoparticles in ethanol is easy to be aggregated.

    ( PS: my work is related to grow silver on silica surface)

  • Ismail Badache added an answer in Big Data:
    I am looking for data sets containing text/articles (e.g. news articles) and users response to these articles. Could anyone suggest any data sources?

    I am looking for data sets containing text/articles (for example: news articles) and users response to these articles (this could be in the format of viewed/not-viewed, a rating, like/dislike, etc). Extra covariates/features would also be appreciative. Could anyone suggest any data sources?

    Edit: This is for a Research Project on Deep Learning concerning text cases.

    Ismail Badache · Paul Sabatier University - Toulouse III

    @Shahab Sohail make a copy/paste of link on your browser's bar and it will work.

    Good Luck

  • What is your experience with lineaments in geological and engineering applications?

    Lineaments are extractable linear features from satellite and aerial images, which are some how correlated with geological structures such as faults.Their use of is very popular and common in applications such as groundwater exploration, site selection for engineering projects such as Dams, association with earthquakes, etc..

    Now the question is: Whta is your experience with lineaments in geological and engineering applications?

    Gamal Seedahmed · University of Khartoum

    Thank you very much Uros. I will take a look to the report.


  • Yang Wu asked a question in Electrochemistry:
    Do you know about the principle of electrochemistry?

    I am here learning the electrochemisty

  • Zolhizir bin Daud added an answer in ICP-MS:
    What is the best method for dissolving rocks for ICP-MS?

    Hey Friends

    I need a clear method to dissolve variable rocks to determine elements (main and rare) by ICP-MS  System. 

    could you help me to get this method in clear steps

    thank you very much 

    Zolhizir bin Daud · National University of Malaysia

    Dear Ahmed

    My suggestion do Total digestion method  for dissolving the samples. Combining Aqua regia + HF solutions.

    Best regard's

    Zolhizir bin Daud

  • Lavdim Kurtaj added an answer in MATLAB:
    How to change the time span time steps in ODE45 in MATLAB?

    Actually I have tried so many options for changing the time steps in ODE45. For example I have changed from tspan [t0 tf] to tspan[t0,t1,t2,t3.....,tf].

    Bot nothong worked MATLAB does it its own way for deciding the time steps.

    This takes too much time for the solution as it is not in control.

    Can any one please tell me the solution for this problem?

    Also we can not write the results of ODE45 in to a file directly, is there any way for doing it ?

    Thanks in advance...

    Lavdim Kurtaj · University of Prishtina, Faculty of Electrical and Computer Engineering, Kosovo, Prishtina

    It should work and return you values at requested times specified with tstep vector, if it has 3 or more elements. 

    As a testing example (MATLAB R2011b) you may create a function

    function yp = ode23_test_function(t,y)


    and solve it and plot results with following instructions

    >> [t,y] = ode45('ode23_test_function', [0:0.1:5], 1);
    >> plot(t,y,'ro'

    Results are given in attached image. 

  • I will be happy to have a comments or discussion about this procedure from those who had experience in the field of urinary diversion?

    I believe that this technique is safe and applicable.

  • Can anyone state the difference between Content Analysis and Thematic Analysis used to analyse qualitative data?

    Has anyone applied both techniques to analyze qualitative data in software engineering? I have used Conceptual and Relational Content Analysis techniques but now want to analyze large qualitative data using Thematic Analysis. Also suggest which one is quick and better method for analysis.

    Jairo Raúl Chacón Vargas · Escuela Colombiana de Ingeniería

    Sadhana Deshpande:

    I recommend you to see "Demonstrating Rigor Using Thematic Analysis: A Hybrid Approach of Inductive and Deductive Coding and Theme Development" by Jennifer Fereday and Eimear Muir-Cochrane. International Journal of Qualitative Methods 5 (1) March 2006  

  • Alvah C Bittner added an answer in Ships:
    Is there anyone familiar with or interested in analyzing the "control system for surface effect ships"?

    For my thesis I need to gather information on system control concepts applications in navigation/motion of surface effect ships.

    I want to know if you have any links/sources/articles on the matter?

    Thanks in advance.

    Alvah C Bittner · Bittner & Associates, Kent WASHINGTON, United States

    A Surface Effects Ship (SES) is one of several types of vessel that rides on a bubble of trapped air to both reduce drag and achieve remarkable speeds for size (e.g. 80Knts).  The air is trapped between two hard sides, with a flex curtains fore and aft.  It was of several concepts extensively studied by the USN -- in 70s -- as means to achieve the concept of an "80Knot-Navy."   There is a lot of occl. motion to control when underway, and when control systems place this above 1-Hz then a lot of human vibration related effects, but when below (particularly near 0.2Hz) then nasty motion-sickness.  TA relatively early and more recent discussion are in Kaplan, P., Bentson, J., & Davis, S. (1981). Dynamics and Hydrodynamics of surface-effect ships. SNAME Trans, 89, 211-247 and Basturk, H. I., & Krstic, M. (2013). Adaptive wave cancelation by acceleration feedback for ramp-connected air cushion-actuated surface effect ships. Automatica, 49(9), 2591-2602.   With a little research, you will find there has been a resurgence of interest in SES in context of augmented two-hulled cat. designs.


    PS SES ride off bubble and very slow under high-seas and then size and weight are can be important to resultant ride.  

    PS Not sure if there might be some confusion with another concept, the  SWATH ... which though not fast, which is a relatively wonderful ride nasty sea-states.  

  • Maria Caeiro added an answer in Algae:
    How can I kill the virus and keep the host ?

    Dear all, 

    I have a solution of algae and a virus and I am  trying to find a way to isolate from the solution the non-infected hosts.

    I have thought of using a 0,2 nm net and then sweep from the surface the algae but I am afraid of hosts that have not been lysed entirely and would potentially carry the virus.

    On other hand in the literature I have seen many scientist using the VIKRON to isolate only their host. However that would be my last choice because i dont want to stress my host with chemicals. 

    Does anyone of you know any other way where I could kill the virus and keep intact host (?)

    Thank you in advance 

    Maria Caeiro · University of Lisbon

    I suggest filtration and sweep the algae from the surface. Then, you may wash the cells in culture medium and subject them to a new filtration. It would be O.K if you could sweep the cells again and start with single cell cultures. The ones not infected will survive and allow new cultures virus-free.

    Good Luck!

  • Chee-Wei Lee added an answer in Patterning:
    Does patterning through E-beam lithography depend on type of Si substrate?

    I have optimized beam current, dose, voltage for intrinsic Si and I got the pattern. But when I use same parameters for P-type Si, I couldn't get good pattern. I see some layer (may be PMMA) on top of the pattern and some places I don't see pattern.

    Chee-Wei Lee · Agency for Science, Technology and Research

    It is always good to optimize your exposure based on the exact type of substrate that you will use eventually. Since EBL generates tiny features, a little bit of difference might become significant.

  • Antoine Dujon added an answer in Distributed:
    How can I verify that a series of random numbers are distributed uniformly?

    I am generating two random numbers. the first one exists in the (0,n] and the other one exists in the (0,1/n]. How can I verify that multiplication of two numbers is in the (0,1] with uniform distribution. it is necessary to mention that each of the numbers are selected based on uniform distribution.

    Antoine Dujon · Deakin University, Warrnambool, Australia

    Peter is right, the product of two uniform distributions is not an uniform distribution seems to be a log-normal distribution.

    Quick simulations with a program such as R, will confirm this.

    # R code
    n.samples <- 50000 #define the number of samples
    n <- 1 #define N
    ni <- 1/n #define the 1/N
    unif1 <- rnorm(n.samples, 0, n) #sample 50000 values from each uniform distributions
    unif2 <- rnorm(n.samples, 0, ni)
    product <- unif1 * unif2 #calculate the product of the two uniform distributions
    hist(product) #plot a histogram of the product

  • Gamal Seedahmed asked a question in Satellite:
    Is there is any other measure/s beside density, length, intersitions, and direction for lieaments analysis?

    Lineaments are extractable linear features from satellite and aerial images, which are some how correlated with geological structures such as faults. Lineaments are typically analyzed by their density, length, intersections, and directions.

    Is there is any other measure/s beside density, length, intersections, and direction for lieaments analysis?

  • Ahmad Rayan added an answer in Autism:
    Can nutrition therapy treat autism symptoms?

    Parents of children with ASD are frequently asking me about Nutrition Therapy for their children. I need some evidences about the topic. Do you agree using Nutrition Therapy for autism? is there any evidence about it?

    Ahmad Rayan · Zarqa University

    Thank you so much dear Toula Kourgiantakis

  • I want to know is there any standard data base for binary prediction or classification?

    I develop some methods but now for examine that for generalization need some data base that have range about 60 to 70 percents accuracy prediction/classification with typical ANN or SVM. to test my methods and compare it with other people work. personally i develop it for EUR/USD time series one step ahead intraday  that is very close to 50 percent accuracy. but i now look for more standard database to test it.


    Arash Moradi · Universiti Teknologi Malaysia

    thanks a lot Lijun Zhao and casson stallings

  • Chiyu Weng added an answer in R Statistical Package:
    How can I use R library(parallel) package?

    I 'm currently work with another library that provides certain functions to treat information (FRBS). In some occasions, the execution is to high and I see how all cores of my computer are not using it. I already searched on Google and everyone suggests the use of "parallel" library, but I have not been able to find a real example that allows me to make use of all cores on my PC. I work on Windows 8.1 with Intel Core i5 processor with 6 Gb of RAM.

    I attached the code I work with (without success) and a picture of the result while running. You can see how are not being used all cores to the top. Any ideas? Thanks in advance.

    Chiyu Weng · National Taiwan University

    Hi José,

    I think the major concern is the training data-set usually cannot be subdivided, which definitely changes the training results(, otherwise you can use package "foreach" as mentioned). Maybe you can find "frbs" source code on Cran R or Github. The training process usually uses many iterations which approximates some values by their algorithms. The iterations are the bottleneck of speed, which hard to subdivide into parallel processes because their data dependency.

  • Different ferrites with different permeability spectra show almost the same shielding effectiveness. Permeability plays no role?

    The near-field measurement was performed in the 200kHz-20MHz range and various ferrite plates were tested by placing between two loop probes.

    Charalampos A. Stergiou · The Centre for Research and Technology, Hellas

    Yes. Permeability ranges from 200 to 1700 in these materials, but attenuation remains high even when permeability drops and losses rise (resonance).