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  • Aditya Rana asked a question in Penetrance:
    Desirable limits of water penetration in DIN 1048 test

    What are the desirable limits of water penetration in DIN 1048 water permeability test? Up to what measurement of water penetration, a concrete is considered suitable to be used in severe, mild or normal exposure conditions?

  • Japneet Kaur added an answer in Multicollinearity:
    What can be the possible reasons of getting a negative constant value in the multiple regression?

    In my research related to social sciences (human resources) I have 5 independent variables which have a highly significant positive correlation with the dependent variable. But on running the multiple regression, the value of constant is appearing with a negative sign though all the Independent variables have positive beta and relationship. The Adj R square value is also considerably good (greater than .60)

    I have checked the autocorrelation (durbin-watson) and multicollinearity (VIF and tolerance) and the statistical tests suggests that there are no such issues.

    What can be the possible reason of such negative sign, when all are indicators are signifying a good strong effect of the independent variables on dependent.

    If this signifies a problem in data or in the tools of analysis applied then what can be the best possible measure to rectify that.

    Japneet Kaur · Panjab University

    Thank you all for addressing my query and for your insightful suggestions.

    Will surely try to review the Holger and Daniel's study along with attempting the mean centric approach.

  • Which reagent will provide a clean lithiation reaction of 4-(thiophen-2-yl)aniline?

    The commonly used lithiating reagent, BuLi can be used for the thiophene-derivatives having primary amine; e.g. 4-(thiophen-2-yl)aniline. Alternatively which reagents can be used to get the lithiated product without interfering the -NH2. 

    Eric B. J. Harris · Australian National University

    I think making the dianion is your better bet; Use two equivalents of t-BuLi , stir at -40° C for 1hr before rapid addition of a single equivalent of your electrophile in THF. Run the reaction fairly dilute in THF, as the hexanes that t-BuLi invariably comes in can be quite disruptive to dianion solubility.
    The strong electronic communication between the desired thiophene position and the aniline functionality may make dianion formation quite difficult.

    Transmetallation works well for iodides and bromides but it is unlikely that any reaction you do with the resulting anion is faster than proton transfer from the electronegative nitrogen atom of the aniline; which is both kinetically and thermodynamically favourable.

    In terms of a good protecting group I would recommend using 1,2-bis(chlorodimethylsilyl)ethane, known as stabase. Which is stable to n-BuLi

  • Supriya Soni added an answer in Voltage Clamp:
    Why are there current fluctuations in hERG patch clamp assay using port a patch (Nanion)?

    I am doing hERG voltage clamp protocol using Port a patch but I am unable to get a steady current. The current fluctuations are so high that I can't even test a single conc. A brief about Port a Patch- its a semi automated patch clamp instrument where solutions, test compounds/ vehicle/ positive control all are added manually. This patch clamp has been recently installed in our lab and has passed the initial validation tests.  

    I have checked the pulse protocol and other settings but somehow I am not able to rectify this problem. Also I am using inducible CHO-TREx hERG expressing cell line. Kindly suggest..

    Supriya Soni · Advinus Therapeutics

    Thanks Peters. I have read that article and I myself had done some experiments at 30 previously. Currently working temperature is 37. I am planning to buy new cell line (HEK-hERG) from Millipore and hope to see more stable and high amplitude hERG currents and of course will modify my voltage protocol as suggested by you. I colud have done some successful studies after incorporating your suggestions but still current stability is an issue. 

  • Mohammadreza Samaei asked a question in Composting:
    Could you help me about a free model for design and modelling of compost production?

    I need a mathematical model for compost production modelling and optimization.

  • Brother Leith added an answer in Cannabis:
    Should cannabis use be decriminalised?
    Official drug policies in developing countries are pretty disastrous, encouraging organised crime and ruining some developing countries. However, before we abandon the War on Drugs we need to be sure the alternative is better and that there are no unintended consequences. In my opinion, alcohol is a far greater social evil, and that we are in denial over this, but I am not persuaded that cannabis is harmless and that controls on it should be eased.
    Brother Leith · University of Southern Queensland

    Does prohibition stop anything? History suggests that it does not. Right or wrong, people tend to do what ever they choose regardless of fear based control tactics. The death penalty has not stopped murder or drug smuggling into places like Indonesia. Perhaps the better course of action would be for governments to stop treating adults like children by prohibiting that which was given by God. Genesis 1:27 - places man as the highest authority and grants that all seed bearing plants are ours for consumption. It appears that consumption can have many meanings and does not necessarily mean to consume with the intent to get 'high'. If it is true that there are possible benefits from using this plant in an apposite manner, then it should not be illegal to know about them. Queensland law prohibits having any material that holds information about this plant regardless of its standpoint. Squashing the discourse and jailing people has not stopped its use or the proliferation of users and I submit that the resources being used to fight the 'war on dope' would be better spent on providing quality education and health systems. Ban tobacco instead, it seems far more insidious. 

  • Farhad Ilahi Bakhsh added an answer in Inverters:
    How can I implement a space vector pwm for a three phase bridge inverter?

    Currently I am working with research on space vector pulse width modulation. I have simulated svpwm for three phase  bridge inverter. How can I implement its hardware practically? 

    Farhad Ilahi Bakhsh · Indian Institute of Technology Roorkee

    Hello Vinu

    Since you have simulated svpwm for three phase bridge inverter therefore it will be better and easier if you interface the generated control signals to the hardware.

  • Rajiv Kumar added an answer in Flow Cytometry:
    What is the minimal cell number per sample for cell cycle profiling?

    Does anyone of you know how many cells is needed to run a cell cycle distribution analysis using flow cytometry (PI staining)? Mouse ES cells have been treated with a certain agent and I expect the cell cycle distribution of the cells to be affected.

    Thanks in advance,


    Rajiv Kumar · Central Sheep and Wool Research Institute

    10K cells minimum for FACS however 50K-100K wouild be optimum!

  • Does anyone knows about best references for teaching of environmental health?

    I need the best book.

  • How to validate a System Dynamics Model?

    Background of decision modelling and System dynamics

    Evandro do Nascimento Silva · Universidade Estadual de Feira de Santana


    Did you do work on a sensitivity analisys? Some times this is desirable the have a comprehension of the variables that mostly impact the system dynamics. I use Vensim instead of Stella, and sentitivity analisys is easily performed with Vensim. Can you do it with Stella? Did the reviewer say more specifically what he meant by "a more comprehensive approach"?

  • Archie Carroll added an answer in Value Creation:
    Is "Economic value added in the context of corporate social responsibility" a good topic for research?

    I want to incorporate EVA concept to find out the value creation for the Green-Ex index (index consisting of 25 companies' stock, launched with their green activities for protecting the environment). Suggest on the topic selection.

    Archie Carroll · University of Georgia

    Good point. But, it is a neglected aspect of CSR that needs continuing documentation. 

  • How can I upgrade a AS WWTP to use MBBR without much civil investment?

    I currently have an activated sludge (AS) waste water treatment plant (WWTP) on site, and I want to decrease the retention time for the treatment process while improving the results from the plant.

    I am currently designing a disinfection chamber with UV to improve the results, and considering a tertiary filter. But I still need to reduce the retention time because the plant is under-capacity.

    Is it logical to install another tank for MBBR treatment after the clarifiers and before the blending tank? Or should I utilize the biological treatment tank and scrap the AS all together?

    Sameer Kumar Dohare · Sardar Vallabhbhai National Institute of Technology

    If you are storing treated wastewater, then my suggestion is to upgrade chemical dosing system, rather than installing UV disinfection

    For your need, i.e. reduction in retention time, you should utilize the existing ASP as an MBBR, by simply adding the required quantity of the media (approx. 50 to 75 vol % of the reactor) with screens in the aeration tank outlet.

  • Ganesan Ramanathan added an answer in Scintillation:
    What is the difference between Radio-luminescence and Scintillation?

    In a first look, both are fluorescence, giving immediate light emission on irradiation.  Mechanism wise both are similar. If both are same then why different terminology? Or is there any technical difference?   

    Ganesan Ramanathan · Australian Radiation Protection and Nuclear Safety Agency

    Radioluminescence is generally of single photon emissions whereas scintillation is a 'burst' of photons. Radioluminescence may be temperature dependent whereas scintillation is not.

  • Could someone here help in information on the poet A.J. Evelyn?

     I am interested in the life and works of the 19th century English poet Alexander John Evelyn, the author (among others) of English Alice and Lyrics of the Sea. Unfortunately I have found no biographical info by Google searching; perhaps someone here happens to know about him? .

    Luisa Isabel Rodríguez-Bello · Universidad Pedagógica Experimental Libertador

    More infrmation at:

    Literature in New South Wales
    By George Burnett Barto

  • Krishnan Umachandran added an answer in Ontology:
    What are infinitesimals------- a 2500-year suspended problem?

    The newly discovered modern Harmonic Series Paradox is one of family members of ancient Zeno’s Paradox, it discloses relentlessly a fact that we human still don’t know what infinitesimals are: with or without numerical meanings, zeros?

    Infinitesimals are there in our science, but what are their positions as numbers or non-numbers or something else theoretically and operationally, ontologically and formally?

    This problem has close relationship with whole fundamental part of infinite related area in our science:
    1, theoretical and practical infinite theory
    2, theoretical and practical limit theory
    3, theoretical and practical infinite related number theory

    Krishnan Umachandran · Professor

    A cartilage growth mixture (CGM) model is linearized for infinitesimal elastic and growth strains. The inherent difficulties in using finite deformation theories, develop a CGM model for infinitesimal strains and seek analytical solutions to specific boundary
    - value problems

  • What is Cuckoo search algorithm?

    In a recent Computer Science Conference (CCSEA-2015) that I chaired at Dubai, there was a nice talk on a paper using Cuckoo search algorithm. I like to share some details about Cuckoo search algorithm from Wikipedia.

    Cuckoo search (CS) is an optimization algorithm developed by Xin-she Yang and Suash Deb in 2009. It was inspired by the obligate brood parasitism of some cuckoo species by laying their eggs in the nests of other host birds (of other species).

    Some host birds can engage direct conflict with the intruding cuckoos. For example, if a host bird discovers the eggs are not their own, it will either throw these alien eggs away or simply abandon its nest and build a new nest elsewhere. Some cuckoo species such as the New World brood-parasitic Tapera have evolved in such a way that female parasitic cuckoos are often very specialized in the mimicry in colors and pattern of the eggs of a few chosen host species.

    Cuckoo search idealized such breeding behavior, and thus can be applied for various optimization problems. It seems that it can outperform other metaheuristic algorithms in applications.

    Cuckoo search (CS) uses the following representations:

    Each egg in a nest represents a solution, and a cuckoo egg represents a new solution. The aim is to use the new and potentially better solutions (cuckoos) to replace a not-so-good solution in the nests. In the simplest form, each nest has one egg. The algorithm can be extended to more complicated cases in which each nest has multiple eggs representing a set of solutions.

    CS is based on three idealized rules:

    1. Each cuckoo lays one egg at a time, and dumps its egg in a randomly chosen nest;
    2. The best nests with high quality of eggs will carry over to the next generation;
    3. The number of available hosts nests is fixed, and the egg laid by a cuckoo is discovered by the host bird with a probability p_a \in (0,1). Discovering operate on some set of worst nests, and discovered solutions dumped from farther calculations.

    In addition, Yang and Deb discovered that the random-walk style search is better performed by Lévy flights rather than simple random walk.

    (Source: Wikipedia)

    Nageswara Rao Posinasetti · University of Northern Iowa

    No. The version 2014b of Global Optimisation Tool box includes PSO besides GA and SA.I did not see Cuckoo there.

  • Chandana Buddhala added an answer in Optimisation:
    How do I remove IgG band covering my protein sample while doing a western blot for ChIP?

    I am optimising ChIP for my protein which is approx. 45kDa in size. Upon doing Western Blot to check my pulldown I see a big IgG band that covers up my protein. Can anyone suggest me how to resolve this? qPCR is another option but I want to first see the pulldown by Western blotting.

    Chandana Buddhala · Washington University in St. Louis

    You could perhaps try the IgG purification kit. I have used this before, but the overall yield is reduced drastically. But you could give this a try. 


    Good luck,


  • Can anyone help me about managing hazardous waste at homes?

    In developing countries managing and collecting of household hazardous wastes is a big problem. Public awareness is low.

  • How are the pulp capping agents tested?

    Are the odontoblast cell lines available?

    Have anyone worked on the odontoblast cell lines? Can you recommend me either collaborators or laboratories anywhere in the world?

    Angela Quispe-Salcedo · Niigata University

    Pulp capping agents are usually tested using histological approaches. Yes, they are odontoblast cell lines, but i have little references regarding its use. Please refer to Dr. Mary McDougall papers for more information. 

  • Gokul Raja T S added an answer in Circuits:
    I have fabricated a DSSC. how to find the fill factor (FF), Short circuit current (Isc) and Open Circuit Voltage using Electrochemical workstation?

    Using multimeter i measured the output voltage and output current while exposing in sunlight. I cant able to find the fill factor using that. We have an electrochemical workstation with us. How to calculate the fill factor of the solar cell? 

    Gokul Raja T S · Mepco Sclenk Engg. College

    thank you sir

  • Selena Hunter asked a question in Patient Experience:
    Do physicians underestimate the degree of post-operative pain patients experience?

    As the study I am doing also investigates this.

    Any other papers looking at this would be gratefully received.

  • Mohammadreza Samaei added an answer in Groundwater:
    Is there any low cost treatment techniques for groundwater withTDS level is around 10000mg/l for secondary uses?

    In general clayey aquifer is yielding poor quality water i.e saline. Which method is feasible to control the TDS ,chloride and Sodium level?

    Mohammadreza Samaei · Shiraz University of Medical Sciences

    I think RO (Reverse Osmosis) is a suitable method.

  • Can any one direct me to resources with information about ground vehicle control system?
    I want to design the drive control system for a ground vehicle but I have not found materials about the block diagrams and electrical diagrams for a ground vehicle.
    I want to design using simulink in matlab, so knowing the state space equations will be helpful.
    Zol Bahri Razali · Universiti Malaysia Perlis

    Here the related article


  • Soheil Soroushnia added an answer in Abaqus:
    Can someone suggest various numerical models for studying fracture process in concrete?

    Can anyone help me in listing out various fracture models for modeling concrete fracture using softwares like ABAQUS. I do also need various numerical models available for studying the fracture process of concrete mathematically. Thanks in advance.

  • Vedamani Basil Hans asked a question in CSR:
    What is the ideal framework for a CSR study in the IT industry?

    CSR and IT emloyees

  • Sharmin Ahmed asked a question in MIMO Systems:
    How to examine is a decentralized control is applicable to a certain MIMO system?

    For the simplicity and convinience of the analysis of the MIMO system i want to decentralize the system into SISO systems.
    But the confusion is,how should i know,is it applicable or not.in simple words,the analysis for SISO systems will be as reliable as of the whole MIMO system.
    if i analyse g11,g12,g22,g21 separately..then can i give  a conclusion for the whole system G???
    any help will be highly appreciated

  • Zol Bahri Razali added an answer in Computer Aided Design:
    Which software is capable to simulate a kinematic collision between tiny particles?
    I want to simulate more than 10^4 particles and figure how they set upon each other
    Zol Bahri Razali · Universiti Malaysia Perlis

    Refer to this


  • Alex Ignatov added an answer in Cancer Cells:
    Are E.coli mortal or immortal?

    In philosophy, there is no immortal individual life. But people used to say that cancer cells are immortal. The question is how to define lifespan limitation of the cells which proliferate by division.  Do you think the bacteria immortal or not?

    Alex Ignatov · Федеральный исследовательский Центр фундаментальных основ биотехнологии (Federal Research Center of Fundamental of Biotechnology)

    Rui-An, theoretically, we can provide E. coli such condition that it multiplies and stays alive for long time. We also can find condition that preserves it alive for very long time. But, from the point of view of probability for such conditions in real live there is no immortal bacteria.

  • Zol Bahri Razali added an answer in Control Theory:
    Can someone help me find this passage from "Automatics and Informatics '06"?
    The passage is: Diop S, Chorukova E, Simeonov I (2006) "Identifiability and observability of some anaerobic digestion models". Proc. of Int. Conf. “Automatics and Informatics’06”, Sofia, October 03-06, 85-88.
    Zol Bahri Razali · Universiti Malaysia Perlis

    Proceeding in http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=1684683&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D1684683