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  • How can I implement security in cloud computing ?

    i have installed cloudsim but i dont know how to implement security in cloud computing . also suggest me if i can use other simulator . please help...

  • Raghuram Tr asked a question in Organic Electronics:
    Could any please suggest texts/materials to learn Organic Field Effect Transistor (OFET) for a beginner in Organic Electronics?


    I am interested to learn about Organic FETs. I am quite new to the area of Organic Electronics, but familiar with the basics of Solid State Devices. Could someone please suggest me books or materials for understanding OFETs for a beginner like me.



  • Mohammadtaghi Heidari asked a question in Comsol:
    I want to simulate multiplication of GEM detecor with COMSOL Multiphysics. Does any one have experience in this field?

    GEM detector can be simulated by solving poisson equation (for electric field) and general form of PDE equation (for particle transport). COMSOL can solve these equations.Does any one know about choosing boundary and subdomain conditions and other problem details?

  • Sayyed Jalil Mahdizadeh asked a question in VMD:
    How can i solvate a structure like a single graphene oxide nanosheet using VMD?

    Dear all 

    I would like to solvate a single graphene oxide nanosheet using VMD. As i checked it out it need a psf and a pdb file of the solute. Can everybody help me with this issue?

  • Donald Myers added an answer in Ground Truth:
    What do you mean by the calibrated data and ground truth data in remote sensing?

    if calibrated data are available, it is possible to
    obtain the explicit semantic meaning of the class transition
    (“from-to”) for a change by matching each single date spectral signature with the standard reference spectra in spectral
    Design of effective unsupervised methods that are independent
    from ground truth data availability is highly attractive in real
    I am getting difficulty to understand this.

    Donald Myers · The University of Arizona

    Two points that need to be emphasized: (1) whether it is "ground truth" data or remotely sensed data there will be a "support" size, i..e. pixel size. The "support" is the shape and magnitude of the area for the measurement and the data value is most often a spatial average over the support. As the support size increases the variability "within" increases whereas the variability "between" tends to decrease (2) the spatial correlation is strongly affected by support size. Hence the spatial (auto) correlation for ground truth data is not the same as that for remotely sensed data.


    2002,M.R.T. Dale, P. Dixon, M.-J. Fortin, P. Legendre and D.E. Myers, Conceptual and mathematical relationships among methods for spatial analysis. Ecography 25, 558-577
    2002 P. Legendre, M.R.T. Dale, M.-J. Fortin, J. Gurevitch, M. Hohn and D.E. Myers The consequences of spatial structure for the design and analysis of ecological field surveys. Ecography 25 601-615

    and also a ms by J. Dungan in the   same  issue, also

    1997 Scaling of Remote Sensing Data D.A. Quattrochi and M. Goodchild (eds), Lewis Publishers,

  • Balázs Kotosz added an answer in Econometrics:
    Could you please tell me what the best reported variable is to measure private savings?

    I am doing a research on remittances and how it impacts the trade balance. I build my theory that remittances in my sample trigger private savings and only small fraction is added to stock of national savings.

    I use gross savings (simply measured as GDP-Consumption) as proxy for stock of savings in the economy, however I received a feedback during a presentation that is is not the best proxy for private savings in the economy.

  • How do you foresee and prevent the outcome of an elective or emergency surgery under anesthesia to end-up in Malignant Hyperthermia?

    Malignant Hyperthermia, was first perceived in 1962 by Denborough et al., characterized by a state of hyper-metabolic syndrome accompanied with high fever and muscular rigidity, due to a hereditary skelelal muscle defect, excited by inhalant anesthetics.    

    Rasheed A. O. Shidi · Clinical Hospital Ribeirão Preto, University of São Paulo-USP & Santa Marcelina - SP.

    So far, specially autossomic dominant hereditary with incidence of 1:15,000 and 1:50,000 respectively in children and adults. 

  • Majid Shahbazi asked a question in Up-Regulation:
    Does any one have experience gene KO and and up-regulation ?

    I  am trying to do gene KO and  up-regulation simultaneously in   in vitro & in vivo

  • Y M A M Wijerathna added an answer in LacZ:
    What is the difference between wild type and commercially available vector LacZ gene?

    What is the difference between wild type and commercially available vector LacZ gene?

    except MCS !!!

    Y M A M Wijerathna · Wayamba University of Sri lanka

    what is Deletion of the amino portion of lacZ (aa 11-41)?

    How it affect? 

  • What is a statistically optimal null filter?

    I am looking for some regions in DNA sequences, a method to do this is the using of statistically optimal null filters. Can anybody inform me about such filters?

    Mohsen Motavaze · University of Tehran

    I am filtering a DNA sequence to find CpG islands, in other words I want to devide the sequence to CpG and non-CpG regions. 

  • What is the best way to calculate the size distribution of nanoparticles ?

    What characterization technique could be the best in that case for instance  we can do the mappping using TEM also. Is there any simulation software to show the size distribution and represent the structure of distribution of particles in the matrix they are embedded in ?

  • Sujit K. Biswas asked a question in Oscilloscope:
    What is the best way to monitor current waveform in a high frequency soft switched converter to be able to verify its proper operation ?

    In the presence of high EMI, normal sensors pick up too much noise which covers up the true waveform on the oscilloscope. Thus Hall effect sensors are not helpful. Resistive voltage drop sensors yield a low signal to noise ratio !

  • What are the possible causes or the predisposing factors for the vaginal cancers?

    We encountered in the camel clinic during gynecological examination of infertile females some cases with vaginal growth. By routine histological examination,   vaginal adenocarcinoma and squamous cell carcimoma were diagnosed. I would like to know the predisposing factors for these cases? Are the mating behavior (frictional for 10-15 min, the penis is fibroelastic type=hard) and the chronic vaginal inflammation contributing factors? What about the condition in women or in the other animals?    

    Ahmed Ali · Qassim University

    Thank you Dr Robert for your interest. I sent you an email for a  future cooperation. 

  • Mahmudunnabi Rabbee asked a question in AutoDock 4:
    "Target.pdbqt" preparation problem?

    During preparation of .pdbqt file I had a warning  like that : Total kollman charge added = -166.952. What's that? explain please.

  • Esteban D. Bonilla added an answer in Dentistry:
    Is there any difference in the success rates of amalgam restorations placed over GIC or Zincphosphate Cement?

    Is there any evidence that the cavity lining (ZnP vs. GIC) influences the success rate of amalgam restorations?

    Esteban D. Bonilla · University of California, Los Angeles

    You are partially wrong and you should be able to correct your proper statement. You are missing the link between tooth structure and the composite resin. This link is the major problem of the most post sensitivity of  all tooth color restorations until now . Composite resin and amalgam are great restorative materials we should know when we can use them. Glass ionomer is a great material to use as a base when we are dealing with deep restorations.

  • Is there any objective standard scale or method to compare the image quality produced by different ultrasound machines?

    In my clinical practice of diagnostic ultrasonography at different health institutes, at primary health care or community level, I have to perform ultrasound using different ultrasound machines from various manufacturers. These machines range from being very very basic to reasonably good one and , thus, have noticeable difference among the image quality obtained. I wish to know is there any method, scale, standard or criteria to measure the image quality produced by these machines objectively.

    Are there any guidelines published by any authority detailing the minimum acceptable level of an ultrasound machine suitable for a given diagnostic work. Say on a scale from 0 to 10, with cut off of (suppose) 4 below which image quality is considered insufficient to provide the minimum information needed for that diagnostic study.

    Sandeep Moudgil · Postgraduate Institute of Medical Education and Research

    @ Nicholas and Christos ( with regards) : I was hesitant to put forth this query of mine but since it was troubling me so i wrote it here.

    I observed that since radiologists graduate from different medical schools there lies gross difference in what they 'perceive' is 'perfect' and secondly the administrators are not radiologists ( and sadly they are to decide while purchasing a machine by any purchase committee). That is why I insisted on an objective criteria. Another point is to define a minimum level of performance ( not worried about what the best is offering after too much of 'algorithms stuff') , as Nicholas mentioned, should be able to do majority of the work up to a acceptable level. Our journals talk of major and big researches (and they should, for the radiology to grow) but such problems which a fresh radiologist faces while practicing radiology at grass root level with the machines which we only see ( if lucky enough) in museums, should be addressed some where. The point is to attain a 'horizontal growth' delivering some basic radiology services to all people. 

    This is a good idea to evolve some guidelines stating that 'this should be seen ( fetal skull tables for examples) but till now there are guidelines  or a list of things for radiologist to look for in specific scan ( e.g. ACR guidelines for antenatal usg) but no guidelines for performance of machine. The reasons are obvious- they do not face such problems. And if we can reach a consensus for that 'bare minimum acceptable level' it will be easier to have good quality machines in any future installations or at least retire the out dated systems.

  • Djamel Teguig added an answer in Omnet++:
    How can one activate logs at every node in omnet++?

    I want to ask that how I can activate logs at each node in my simulation in omnet++.

    I want to know that how many packets a node has sent and received?

    Djamel Teguig · Royal Military Academy

    in omnetpp, 

    make help for logged function and it gives you details to how activate logs at nodes

    Best regards

  • Jonathan Edwards added an answer in Psychology:
    Can somebody help me understand reductionism in psychology?

    I have read some journals but having trouble understanding reductionism in psychology. I understand the different stages going from behavioural, cognitive then to biological but what is the importance of this? also what are the issues within reductionism and psychology?

    Jonathan Edwards · University College London

    This is all getting a bit oblique. Who denied God, I wonder? I can guess. But then for Descartes and Leibniz God was not supernatural - He was the reason for everything natural - and nothing else. 

  • Steingrimur Stefansson added an answer in Graphene:
    Is ultra-sonication an effective method to increase the specific surface area of carbon nanopowders?

    Can ultra-sonication be considered as an effective method/treatment in order to increase the specific surface area of carbon powders (e.g. carbon nanotubes, graphene nanoplatelets, etc)?

    Steingrimur Stefansson · HeMemics Biotechnologies Inc

    Hi Nikolaos, as Khosro said, sonication can separate aggregated carbon nanomaterials, but you will have to include detergents like SDS to keep them separated after the sonication.

  • Which is the best tool for analyzing the WSN?

    I am using Ns2 for WSN simulation. Can anyone help me for an alternative efficient tool for the same.

    Djamel Teguig · Royal Military Academy

    I suggest omnetpp. it is easy work with it.

    all OSI layers can be found in it

    Best regards

  • Jean Constant added an answer in Byzantine Art:
    Does anyone know of information on the imaging (murals) enthroned Virgin Mary stepping serpent?

    Seeking for respectively as monuments and symbolism of this visualization in ecclesiastical monuments to the 18th century, with relevant bibliography.

    The Serpent and Crescent Moon at Mary's Feet...


  • Younes BOUALLEGUI added an answer in Protocols:
    Can anyone give me suggessions about qRT-PCR?

    I would like to know if the reverse transcription reaction influence or not the DNA expression, in other way I would say which appropriate protocol to convert RNA to DNAc for real time PCR reaction, because i found many protocol with different time of incubation, could you suggest good and not expensive one, Regards.

    Younes BOUALLEGUI · University of Carthage

    Thanks, Martin!

  • Aldo Dall'Osso added an answer in Reactors:
    Why is the fast and thermal adjoint fluxes are equal in an interface while the forward fluxes are not

    In an infinite Slab with an infinite reflector, the thermal flux is lower (than fast flux) in core and peaks up in moderator.   However the adjoint fluxes are opposite. two questions

    1- why are the magnitude of adjoint fluxes are the inverse of forward flux?

    2- why are the two adjoint flux (fast and thermal ) are exactly equal at the interface (boundary of core and reflector)

    Reference : Figure 7-4 Duderstat&Hamilton (Nucl reactor analysis)

    Aldo Dall'Osso · AREVA

    The above discussion was based on physical considerations. I have no mathematical derivation of the adjoint behavior in the slab reflected reactor. Hopefully someone else will give the answer to that.

    Best regards,


  • Zainab Jaafar added an answer in Public Speaking:
    Starting an English Language Development unit?

    I'm planning to start an English language development unit in my work place. It is a scientific research center in which the staff are of varieties of scientific specializations.

    The main purpose behind the unit is to help enhancing their linguistic capabilities as far as the academic use (like in research writing, public speaking, etc).

    I'd appreciate your suggestions for better planning.

    Zainab Jaafar · University of Basrah

    Pls share with experts you know :)

    Thanks in advance

  • Yiou Liu added an answer in PDMS:
    How can I peel off PDMS micro pillar arrays from the casting mold without tearing the pillars apart?

    I fabricate PDMS micropillars with LIGA-made casting mold (Nickel Metal Sheet) consisting sinking holes of 240µm depth and around 18µm diameter. My casting setup is as the figure attached. A cannula with a diameter 5mm is clipped tightly together with the casting sheet with one or two clips. Sylgard 182 Silicone for casting the pillars is moved into the cannula by a pipette. Then after the degassing process and the baking process the silicone becomes cured.

    My question is concerning the peel-off process. Currently I first remove the clips and then put the whole thing into a vibrating bath (the bath is filled with isopropanol) and wait for the cannula with pillars and the casting sheet to become apart. The pillars are expected to be 240µm high (same as the hole depth). However, most pillars I get suffer from not enough height, that is they are torn apart after the silicone get cured. 

    May I ask if anyone has similar experiences and do you have any suggestions concerning the peeling off process? Or maybe anyone has some other ways for peeling them off?

    Thanks very much!

    Yiou Liu · RWTH Aachen University

    Hi Mr. Bahrieh,

    Thank you for your answer. 

    Usually I clean the mold with isopropanol and then water, then dry it with pressured air. Then I put it into fridge for about 10minutes. Afterwards I pour the PDMS. May I ask if you find this process not that OK? Thank you very much!

  • David Aphkhazava asked a question in Cell Death:
    Which model would be best to study molecular mechanisms of ALS?

    I would like to do some research about ALS, mSOD is not a good model, does anyone have some suggestions which model would be good or which novel model of ALS (in vitro and mouse too) would be better than currently existed ones for therapeutic and diagnostic purpose? 

    I would like to study the mechanisms of cell death during ALS, also to test different compounds to use as potential drugs.  

  • Peter Schluessel added an answer in Surface Tension:
    What is the relation between the surface tension and acidity/basicity?

    Surface tension of pure water is 72 mN/m. But it varies with the addition of acids and bases. why?

    Peter Schluessel · European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT)

    Cohesive forces are responsible for the surface tension. Within a liquid these forces on a molecule are equal in all directions, while at the surface the molecules do not have neighbors at all sides, thus creating surface tension. The cohesive force between water molecules are particularly strong as each molecule can make four hydrogen  bonds to other molecules. Other substances may have fewer bonds depending on its molecular structure. Therefore a mixture of water with other liquids can reduce the cohesive forces among the molecules and thus the surface tension.

  • Beno Zerr added an answer in Spectral Analysis:
    How can I compare the frequency spectra of two different audio signals?

    I am currently working on a project which requires me to characterise deviations from baseline using acoustics. I already have generated the frequency spectra of both the signals, but I am having trouble comparing them to see if there is any difference.

    Any help?

    Beno Zerr · Ministère de la Défense


    To compare spectra of 2 signals , you can try magnitude-squared coherence or cross power spectral density

    kind regards

  • Christian O Isichei added an answer in Hepatitis B:
    Is anyone interested in doing data analysis and writing up of a huge set of data about HBV from my work?

    This should make a good paper and you will be an author. This work (the analysis and writing up) should finish in the next two months. If you have time and do not have busy schedule, please contact.  You should be a very good statistician and writer. No time waster please (This is not paid work), the only reward you get is the authorship! 

    Christian O Isichei · University of JosTeaching Hospital

    Since some persons are interested,can we share the work out to all those interested?

  • Can be considered a marine ecosystem of high new primary production (Pnew), as Resilient Ecosystem after passing through a time of low Pnew?

    After several months or seasons that an ecosystem has negative anomalies Pnew, and suddenly that behavior changes positively,... I can refer to the marine system was able to be restored?