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  • Anni Nielsen added an answer in Syntax:
    Do you have SAS syntax that selects an age and sex matched (random) control group?

    I desperately need help with generating a matched control group through SAS. We have records of individuals which have been exposed. We have an unexposed control group. I need to match each exposed individual with control group individuals on 1:10 basis. The matching parameters are birth year and sex. Is there a way to do this so I do not have to match each birth year separately? Do you have SAS syntax or do you know a website I have to visit?

    Anni Nielsen · University of Copenhagen

    Thank you Horst and Brian. We will try to use the syntax provided by Horst. :-)

  • AR Reddy asked a question in Energy Harvesting:
    Are super capacitors suitable for energy harvesting ?

    We know that super capacitors store 10 to 100 times more energy per unit volume or mass and available capacitance greater than 1000 Farads.

    Are these suitable for energy harvesting from RF, light and wind ?

  • Svetlana Derkach added an answer in Gelatin:
    Are there any alternative to beef and pork gelatine that are suitable for vegetarians or people who avoid beef and pork?

    The aim is to identify gelling systems that mimic the rheological and sensory properties of gelatine to make food matrices suitable for vegetarians.

    Svetlana Derkach · Murmansk State Technical University

    It is reasonable to use fish gelatin – gelatin made from fish skin or fish scales. It is a good alternative to beef and pork gelatin.

  • Fathi Omer added an answer in Drought Stress:
    How can I set a drought stress experiment in pot with Ec=4 bar ?

    Every researcher uses Fc to calculate the amount of lost water, but at this time i want to fix it on EC=4 bar.

    Fathi Omer · University of Duhok


    find attached, hope this will be helpful if you need to measure the stress endued by PEG


  • Sudev Naduvath added an answer in Euclidean Geometry:
    Does anyone know how much there is evidence (mathematical) Pythagorean theorem?

    Proof which appeared in Euclid's "Elements" is not Pythagorean proof. Russian mathematician Loomis, was 1940 published a book of mathematics in which there are over 200 proof of the Pythagorean theorem.  Do you know some proof of this theorem, which so far no published?

    Sudev Naduvath · Vidya Academy of Science & Technology

    As mentioned in previous comments, there are many proofs for Pythagorean Theorem. Please see some interesting remarks for an immediate reference.

  • Peter Pediaditakis added an answer in Mitochondria:
    How could I record mitochondrial transportation in vitro cancer cells?

    Mitochondrial transportation is essential for the function performing of mitochondria. But I'm wondering how to record the transportation of mitochondria in vitro cancer cells and also how to transform the images into quantitative data.We now got a FV1000 confocal microscopy and MitoTraker RED probe that could label the mitochondria of living cells  to show red fluorescence. Thx

    Peter Pediaditakis · University of North Carolina at Chapel Hill

    You are wanting to watch the redistribution of mitochondria with in the cell?

    Visualize the mitochondria by TMRM and turn the cytoplasm into a green background with Calcein.  

    See reference:

    Kim, J.-S., Ohshima, S., Pediaditakis, P. and Lemasters, J. J. (2004), Nitric oxide protects rat hepatocytes against reperfusion injury mediated by the mitochondrial permeability transition. Hepatology, 39: 1533–1543. doi: 10.1002/hep.20197

  • Reina Lim asked a question in Localisation:
    Immunofluorescence for HIF-2a?

    Has anyone performed mmunofluorescence successfully for HIF-2a  or able to demonstrate HIF nuclear localisation in human hepatoma cell lines? 

  • Mahdi Abdeddaim added an answer in Vibration Control:
    What should change if we move the damper location from ground-floor to top floor ?

    Dear researchers;

    I'm using a damper in a five-story structure, I'm asking what should I change if I decide to move the damper from ground-floor to the top floor ?
    - Should I juste change the location matrix of the damper in my equation of motion ?
    - If the damper is fixed at the base of the building which is supposed not moving during the seismic excitation, would that change if we put the damper in the top-floor ? in this situation the damper will be fixed at the 4th floor, which is not fixed but mouving during the seismic excitation.

    Best regards.

    Mahdi Abdeddaim · Université de Biskra

    Dear Cengiz,

    Right now we are limited to a numeric simulation, but we are looking forward for an experimental studies to confirm what we are getting from simulations.

    Best regards.

  • Sambasivarao Karlakunta added an answer in OpenCV:
    How can I read/write uncompressed videos?


    Please, i am using opencv 2.4.9 on ubuntu 14.04 and i try to read/write an uncopressed video but it gives me a segfaults on cvQueryFrame(capture) when i try to open a rawvideo. Can help me?

    Thank you

    Sambasivarao Karlakunta · Hi-Tech Robotic Systemz Ltd.

    You can try debugging the code for errors. Segmentation faults might be occuring because of some other error. Or you can try writing the video in some other format than avi. Because i have been working on video processing from so long. I record the output videos everytime using videowriter only. It didnt give me any error anytime. 

    My request is try debugging the code once. Thank u

  • Dirk Hueske-Kraus asked a question in Love:
    Does anyone know about studies which link the usage of "employee idea systems" ("employee suggestion management") to staff satisfaction?

    I'd love to hear about this and get references.

    Of course, any gut feeling about whether there is such an effect is welcome as well.

  • Fabricio Faitarone Brasilino added an answer in Likert Scale:
    Can you present data in a chart in % and then use the mean to show the average response?

    I have little knowledge on statistics but recently I have had to use a survey in the shape of a Likert scale to test attitudes. So far I have presented the findings in a chart, showing the responses in percentages. For instance, 30% agree, 40% disagree etc. I have then used the mean to show on average the sample response to each Likert item. I know there is a debate on whether you should use mean or not but I just wanted to know if this is ok to present the data in a chart and then use the mean to demonstrate the average response, for a basic analysis? Than you? 

    Fabricio Faitarone Brasilino · Universidade da Região de Joinville (Univille)

    Aproveite para usar uma forma de associação, qui-quadrado.

  • Monica Marra added an answer in Scientific Publication:
    Is anybody aware of a journal with an anonymous review process?
    I think that could increase the quality of research, if a article is chosen for publication on the quality of the results and not on the name and reputation of the researchers.
  • Nuriyah Mohammed added an answer in Graphene Oxide:
    How do I coat a monolayer GO on the top of SiO2 substrate?

    Is any one tell me what I have to do with spin coating device to get monolayer graphene oxide?

    my way is:

    1- plasma cleaning to get SiO2 substrate with high hydreopholic

    so can you tell me what concentration of GO solution I have to use


    parameters should be used in spin coating like time, rpm etc? 

    Nuriyah Mohammed · The University of Manchester


    i wang yo know the best acceleration in spincoating did you use

  • Behzad Ghafarizadeh added an answer in Abaqus:
    Excessive element distortion in 2D modeling of composite materials cutting with ABAQUS?


    I modeled the 2D cutting of fiber reinforce plastics (composite) materials with ABAQUS. As is shown in the figure, I have problem with  excessive element distortion and chip formation. do you have any idea how to solve this problems? 

    Thank you in advance for any help you can provide.

    Modeling parameters:

    -Material : composite 

    -Failure criteria : Hashin (damage stabilization 1e-7 )

    -ALE adaptive mesh (frequency 10, sweeps 1)

    -interaction (surface to surface contact- penalty contact method)

    -step :dynamic explicit

    -Mesh type:  CPS4R , plane stress 

    Behzad Ghafarizadeh · École de Technologie Supérieure

    I mean Step-Edit step- basic -time period (0.001)

                Step-Edit step- Incrementation- time scaling factor (0.01)

  • Fathi Omer asked a question in Durum Wheat:
    Which is more resistance to drought stress, bread or durum wheat, and why?

    Please if you have convincing answer for: Which one is more resistance to drought stress, bread or durum wheat? why?

  • Abdul Ghaffar added an answer in Ligation:
    Does overnight ligation on +4 with PEG inhibit transformation?

    Hi, everybody! Today I was browsing Neb website and and found in troubleshooting section, that overnight ligation with PEG containing buffer inhibits ligation. Is it true? Can anybody share some personal experience about this issue?

    Abdul Ghaffar · Government College University Faisalabad

    Doesnt inhibit ligation 

  • Patricia Ryser-Welch added an answer in Genetic Programming:
    Is the run time of genetic programming increased by the increase of the number of data for regression ?

    Actually, I written a GP code for regression in Matlab! However, due to symbolic nature of the code and the necessity of using time consuming commands like 'eval' for evaluating the fitness of each equation (to replace the input values in the function and evaluation), the run time of the algorithm increased dramatically when using large data sets (e.g. over 2000)?

    Is there any survey?

    Thanks in advance !!

    Patricia Ryser-Welch · The University of York

    There is a library in C for CGP. 

  • Ross S Fontenot added an answer in Optical Devices:
    Anyone familiar with the alignment of the double monochromator SPEX 1680B?

    We have a SPEX 1680B double monochomator that is badly out of alignment. I have set it to 0 nm and shined a He-Ne laser through it. I have aligned it vertically. The laser beam goes through the ends fine. However, when we start to the align the gratings, that is when we have problems. I can align it at 530 nm, but when I move the monochromator to red (613-630 nm), the light no longer goes all the way through and it starts missing the second set of mirrors. I can then align it on red, and the same thing happens when I go to green. Are their any sort of tricks to align this double monochromator or does anyone know what we are doing wrong here?

    Ross S Fontenot · Naval Undersea Warfare Center

    Clarification: The HeNe laser was used to calibrate the 0 nm position. Once the gratings were aligned, we used a Xe lamp and spectrometer to try and do a calibration using other wavelengths.  

  • Surender Pratap added an answer in Graphene:
    Fermi energy in Graphene nano ribbons?

    I am simulating graphene nano ribbons,and i want to add my magnetic field term in Hamiltonian,is there any other method than Pierls Substitution or not.


    Surender Pratap · Birla Institute of Technology and Science Pilani

    Thanks sir ,i have taken total flux is equal to -a*B*yn=if magnetic field is 4T,a=1.0,yn=4t means total is equal to -32.2624,total flux.

    Hope this one is fine sir


  • Joydeep Bhadury added an answer in Epitope:
    How is it possible that an antibody recognizes the cleaved form but not the full length protein on a denaturating western blot?

    I’d like to stain for apoptosis markers cleaved capase3 or cleaved PARP on denaturating western blots. There are multiple antibodies available in the market that claim to recognize the cleaved fragment but not the full length protein. But how is this possible? The cleaved fragment is part of the full protein, thus the epitope present in the cleaved fragment is also present in the full-length protein… and I guess conformation should not be contributing under denaturating conditions.

  • Nizar Matar added an answer in Renewable Energy:
    Are renewable energy technologies really green?
    Renewable energy technologies are the solution for the reduction of greenhouse gases generated by the power sector. However, we have to take into account the complete life cycle of these technologies (How much energy is needed to produce them, to transport them, to install them, to maintain them, and to dispose of them). Taking into account all these factors, and the relatively high initial cost, can renewable energy still compete with fossil-fuel sources? Even if we internalize the environmental costs of the latter?
    Nizar Matar · An-Najah National University

    Renewable energy technologies are not really green & clean from (A) to (Z). At present, transition from fossil fuels is suggested to proceed towards either more clean synthetic fuels such as methane and/or methanol "derived from coal the last fossil fuel to be depleted" or into using renewable energy sources including solar, wind, geothermal, hydropower, biofuels, and waste-to-energy technologies. The current state of knowledge in these alternatives is not (as we wish) and each one of them has its own negative side effect(s). I am not aware of any research into "fully green" technologies, and what really goes on is the logic of "something is better than nothing" with many concerned persons hoping for close to greenish achievement. The significant problem, here, is the lack of true serious political decision from the most influential countries to go green & to stop the ongoing harm to the environment.   

  • Nicolas Clercin added an answer in Water Supply:
    Anyone know that what is the relationship between high algal bloom and bacterial population?

    in the water tank of my lab i found high algal bloom. when i call an expert for this problem he said i have to test my water supply for bacteria population.... i want to know that what is the relation between high algal bloom and bacterial population.....

    Nicolas Clercin · Indiana University-Purdue University Indianapolis

    If your algal bloom is made of Cyanobacteria, you already have a lot of bacteria in your water.

    From my personal experience in freshwater systems, the relationship in average is for one eukaryotic cell there are x10 more bacteria; and x10 more viruses than bacterial cells. This ratio may be shifted under different bloom conditions if you assume intense competition for resource per small unit of volume.

  • Go J Yoshida asked a question in Mutation:
    Whether or not sulforaphane (SFN), activator of Nrf2 signaling, promotes or suppresses tumor progression???

    Redox stress is maintained at low level in cancer cells. Not a few types of cancer including non-small cell lung cancer (NSCLC) has constitutive activation of KEAP1-Nrf2-ARE signaling pathway due to loss-of-functional mutation of KEAP1 or amplificative mutation of Nrf2

    Sulforaphane (SFN) is widely known to promote nuclear translocation of Nrf2 in normal cells, thereby many people believe that broccoli, a good source of the glucosinolate precursor of SFN, is beneficial to prevent carcinogenesis. 

    However, I am not sure whether or not SFN, activator of Nrf2 signaling, promotes or suppresses tumor progression???

    Activation of Nrf2 signal possibly worsens the malignant potential of cancer cells. Nrf2 prevents cancer development while promoting during the progression including invasion and metastasis.

  • Adrian Ioan Petrariu added an answer in HFSS:
    How can I increase the real part of an microstrip antenna impedance using lumped elements?

    I need to match in impedance an microstrip antenna using HFSS. The real part of the impedance varies too much when I change the antenna structure. Is any way using lumped elements to give a certain value for the antenna impedance in order to match it with a known IC impedance? Lumped elements for normal structure of an antenna can be used for a microstrip antenna too? Thanks!

    Adrian Ioan Petrariu · Stefan cel Mare University of Suceava

    Thanks all for the answers!

    Aditya I've used in the past ADS but now we have license for HFSS and I try to resolve my questions with this software. There is a tool called Smith Tool that can match easily the impedance with the desired component, but this will give me only a practical approach. I need to find a match between the results obtained and the theoretical approach (which I don't have it for my requirements). Now, the method that I've used is the Smith Tool and with the values obtained I've make lumped elements (without having a math background on it).

    If anyone have knowledge where I can find a relation between the simulated results for microstrip lumped elements and the theoretical meaning of this please let me know!


  • Bartosz Trzaskowski added an answer in Gaussian (Software):
    How do I optimize a molecule by multi layered ONIOM Model (high and low) with Gaussian 09?

    Dear all

    I am doing an optimization of a molecule with multi layered ONIOM Model using a Gaussian 09. The calculation ends in normal termination only. But when we visualize the log file (output), it shows the Warning error message. i.e

    connection Glog:: parse_Gauss_charges()

    Error reading ESP atomic charge data

    Line number 563136.

    Not able to visualize as high and low layer in the output file.

    Thanks in advance

    Bartosz Trzaskowski · University of Warsaw

    1. Are you sure that the calculations finished properly (no errors in the output)? You can check the log/out file in the text editor.

    2. Are you using pop=mk, pop=chelp or something similar? GaussView is known to have problems with proper display of ESP charges - but this is a purely display-related problem. You can try displaying in GaussView the checkpoint file (instead of log/out file) or use a different software to visualize the structure (molekel, molden)

  • Priyanka Garg asked a question in Acetonitriles:
    What is the pKa value of methanol, water and HCl in acetonitrile solvent ?

    I can't find this if anyone know this, so please help me.

  • Verena Hoelzer added an answer in Mangroves:
    Can anyone help with a Shannon Index comparison among different habitats?

    For my study I am comparing diversity of mangrove epibiont communities among estbalished, reforested and deforested mangrove sites.

    Asking a question to the theoretical background of the Shannon Index: In which extend can I use the comparison of Shannon-Indeces in-between sites with different environmental settings ? Do habitats need to be similar to a certain degree to apply and compare the Indeces

    Verena Hoelzer · Leibniz Center for Tropical Marine Ecology

     Dear Andrey, thank you for you help, this is the kind of information I am looking for..

  • Joydeep Bhadury added an answer in qRT-PCR:
    What is the reason of such abnormous amplification curves in qPCR(see attachments)?

    Briefly, I get strange amplification curves (see picture below, both linear and log amplification curves. But melting curves are OK, and I checked on electrophoresis that I have the right product in the right wells. I already had changed the concentrations of the template and some components in the reaction mix with zero success. I assume smth is wrong with the program settings. I use ABI StepOne Plus system, other people use it as well and get good results. I have previously worked with ABI Fast7500 and Bio-Rad systems in another lab and never had such a problem.

  • Stam Nicolis added an answer in Special and General Relativity:
    In GTR does the metric determinant have to be less than zero for every reference frame or it is applicable only for galilean frames of reference?

    if gik is the metric tensor in general ,is the determinant g always less then 0 or it is right only for galilean frames of reference?

    Stam Nicolis · University of Tours

    Indeed-but I'm thinking, for instance, of situations like horizons-where things get tricky and, as shown by the singularity theorems, coordinate singularities are generic and, therefore, can't be excluded in advance.