ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.

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  • Who are the stakeholders engaging in disaster risk reduction process? What are the roles they play? And how effective their roles are?

    Academia provides scientific knowledge; governments provide regulations, enforcement, and financial support; organizations bring parties together, advocate and promote participation, etc.; and private sectors innovation and technical support.

    Jayaraman V · Indian Space Research Organization


    thanks. Small correction though. The question was posed by Majeed. I only answered his question. Hope Majeed is reading your answer too

  • Subodh K Sharma added an answer in Scattering:
    Why do elastic electron-electron interactions IN low scattering angle, while electron-nucleus interactions IN higher-angle scattering in TEM ?

    Why do elastic electron-electron interactions usually result in a relatively low scattering angle, while elastic electron-nucleus interactions cause higher-angle scattering in TEM ?

    Subodh K Sharma · S.N. Bose National Centre for Basic Sciences

    Large angle scattering is perhaps due to significant presence of multiple scattering from constituent proton and neutrons

  • Morteza Borhanipour added an answer in Biodiesel:
    How to find the H/C ratio of soot samples with CHN test (elemental analysis)?

    Greetings dear scientists,

    I have soot samples from Diesel and Biodiesel with results of CHN test(elemental analyze). Is it possible to calculate the H/C ratio of each samples with this kinda data or do I need to do FTIR test?

    Morteza Borhanipour · King Mongkut's Institute of Technology Ladkrabang

    Thanks a lot for your kind  answers and guidance 

  • Why Flat Organizations Need Project Management Software?

    Weak project management often results in undefined objectives, poor communication, and missed deadlines. Without managers, can flat organizations remain efficient and organized?

    Manish Puranik · Project Management Institute, USA

    Thank you all for your valuable inputs and insightful suggestions, I sincerely appreciate it and would try to act upon them to the best of my level. However, I need to clarify some points here as I must to support my concern, I believe.

    If you observe closely, I have provided a link below ‘my question’ and its description. This link leads to an article with the title ‘Why Flat Organizations Need Project Management Software?’ on http://Proofhub.com by Jenna Puckett, a staff writer for ‘TechnologyAdvice’, wherein she has tried to discuss this topic with all aspects of it. Although she has tried to make her article as comprehensive as possible, with a subject having a global perspective and local effect, I thought I could get some more views on it from Research Experts who might have deliberated the subject matter from diverse perspectives.

    Secondly, being an Independent Consultant for Organization Development and Project Management, I come across various types of organizations with different structures and process methodologies. To summarize what I have observed in my practice so far is – hierarchical organizations practice a top down approach where there is less communication and more execution without much brainstorming; very common practice in most of the mechanically-operated-workflow-organizations. On the other hand there are so-called flat organizations that strive for inclusion of entire TEAM (or ‘Board’ if you would like to call it) in the decision making process by empowering it with tools like communication and collaboration.

    Nevertheless, there seem to be a dire need of keeping transparent to facilitate the creative process in a flat organization. At the same time, every innovation that is borne in mind needs to be manifested, developed and tracked; not to mention, logged and recorded, as it progresses towards fulfillment. And this entire journey of an idea to its realization and the process of making it possible should must be governed by strict baselines like Cost and Time and regularly checked for Quality and Risks. Here comes the Project Management tool in picture. ‘Project management software empowers employees to self-organize every project from start to finish, meet deadlines with greater precision, and turn innovative ideas into reality…’ as Jenna suggests to conclude her article which I wholeheartedly agree with.

    Now, hoping that I have tried to make the picture a little clearer, I would greatly appreciate if I could get some useful and applicable insights, like the one from Henrique Rocha (Thanks, Henrique), on ‘Having, Employing and Exploiting PM tools in a Flat Organization’, so to say. Although I understand that this platform is academic in nature and emphasis on theory would be its elemental characteristics, I would like to reiterate Albert Einstein here ‘If the facts don't fit the theory, change the facts...!’ Thank you all.

  • In my msc culture in passage 1 I found a contamination that I don't know what it is. Would you help me identifying it, please?

    The black thing in picture.

    I change all of my materials and change my place but I see them after passage 1.they are float amd my cells are alive in that media.

    Sankari Dharmlingam · SRM University

    Hi Shirin 

                      You can use the Antibiotic- Antimycotic  (Invitrogen -CAT NO-15240062)

  • Radhika Marwaha added an answer in VANET:
    Can anyone help me in calculating performance metrics like delay,throughout,etc from ns-2 trace file for vanet routing protocols?

    I am not familiar with the scripts.

    Radhika Marwaha · DAV University

    @Abdul Razaque 

    Sir Its very kind of you. Sir I have four trace files for protocols of AODV,AOMDV,DSDV,DSR. I have generated them for 48 nodes. I want graphs for all four protocols for the performance metrics as shown in the research paper attached.Sir please if you can generate these graphs for all the four trace files as soon as possible as I need to submit my project within 1 or 2 days. Thank you.

  • Liang Mi added an answer in Ground Truth:
    We are looking for a localisation/odometry system for indoor mobile robotic (GPS-denied environment)?

    We are looking for an odometry/localization system for indoor mobile system (GPS denied environment) that can be considered as ground truth (accuracy <cm/m).

    The result don't have to be real time, we just need a good accuracy in the path estimation.

    Liang Mi · Arizona State University

    There are two methods I can think of. One is to use WiFi RSS or RSSI. The other is to use accelerometer and gyroscope embedded in the terminal device e.g. smartphone. Fingerprinting is a popular way of using Wifi signal. And using accelerometer and gyroscope doesn't need outside signals. There are plenty of papers talking about this topic. 

  • What is the best definition for the surreal numbers?

    I think that surreal numbers are very important mathematical concepts

    of numbers including all kinds of infinite and infinitesimals,

    We need a simple definition for such concept.

  • Is it time we forget climate change & focus on the 'Human Dimension'? Is it not obvious that nature can heal itself, if only left alone?

    A lot of hue and cry is made about climate change and the environment in general. Public and private money is poured into research to study its effects on the environment, sustainability etc. Should we study nature or ourselves?
    Human activities have been found to have a direct correlation to climate change and its impact on the environment(I=P x A x T, the Ehrlich and Holdren equation), in spite of what some complacent sections say to protect their own self interests. It is pretty obvious that it is human beings who need to be studied. We hardly know about Human nature. We can scarcely predict human behavior. We need to find out why we think like we do and why we do what we do and why, in spite of all knowledge and wisdom, consume more than what we need, in the form of addictions to consumption and imbalance not only ourselves but also the family, society and environment around us..
    Humanity is directly responsible for all the unnatural imbalances occurring on the planet. Yet we refuse to take responsibility and instead focus on climate change, or fool the public exchequer with a 'breakthrough in renewable energy just around the corner'. We scarcely know what drives human beings. If we had known, all the imbalances around us would have had solutions. Are we blindly groping in the dark of climate change because we don't know the answers to our own nature?
    Is it not high time we focus on what makes us human, correct our consumptive behavior and leave nature to take care of climate change? Why focus effort on 'externals' when the problem is 'internal'- 'me'?
    Aren't we addicts denying our addiction and blaming everything else but ourselves?

    " We are what we Think.

    All that we are arises with our thoughts.

    With our thoughts, we make the world." - Buddha 

    IMHO, We don't need to save the World. It is enough if we save ourselves from ourselves. The need of the hour is not vain glorious interventions, but self-restraint and self-correction!

    Raveendra Nath Yasarapu · Technische Universität München

    Dear Antonio,

    If, as you say, the vested interests of the right are in force to keep things in status quo, can we do a "Gandhi" here? A stronger opponent cannot be fought head on. An emaciated, but principled old man brought down the British empire with nothing more than the power & sincerity of his beliefs. What we need is a grassroots movement, so simple, so effective and so easy that it will be emulated all over the globe to bring down the right?

    Gandhi started with the boycott of foreign, British industry made goods. If we want change, we must BE part of the change, not just being scholars. Can the scientific community boycott all products which are seen as a threat to climate change? In THOUGHT-WORD-DEED? It is the hard way but the most effective way. And there are no shortcuts. Anyone game for this bold experiment where the 'lab rat' is yourself?


  • What are pros/cons of combining convenience sample of students with mail sample of residents when the mail sample underrepresents local student pop?
    We conducted a survey in which part of the data was collected via a mail implementation (largely using the Dillman method). We also collected data using the same hard copy instrument with students on campus at the local university - basically a convenience sample.

    In the mail survey we had about 6% students. As the students make up about 15-20% of the population of the town we are researching (Boulder, Colorado) we under-represent them in the mail version.

    The student respondents in the mail version also tended to be older, higher income, higher education, I suspect more likely to be grad students than the convenience sample on campus.

    My question is - given the different sampling methods what are the pros and cons of including or not including the convenience sample in our analysis? Do we have a more representative sample including them or excluding them. If we include them in our analysis will our sampling method be defensible.
    James R Knaub · Energy Information Administration

    Jeffrey -

    I see that you wrote your question some time ago, but assuming you may still have some interest in this, now or in the future, I have some comments.

    First, I looked up the "Dillman Method," and it appeared to be a data collection method, only concerned with producing a high response rate, but said nothing about the sample design or estimation and inference you might want to do. Convenience sampling, on the other hand, is a sampling method, but one that, especially with such a small sample of such a large population, is not going to yield much, if anything, that is useable. It is one of many kinds of purposive/nonprobability sampling methods. They may be used to explore some ideas, but cannot be relied upon to be 'representative' under any definition that may involve estimations for a population. The mail survey was larger, but not knowing the survey methodology, I cannot say what can be done with those results.

    For another question on ResearchGate, where someone asked what "representative sampling" meant, I noted that the word "representative" may mean different things to different people, but if you want to say it means you can obtain reasonable estimates for information on populations, say estimated totals or means, there are three basic approaches (well, two plus a 'combined' one):

    (1) design-based (randomized) sampling and estimation methodology, (2) model-based (regression) methodology, and (3) model-assisted design-based methodology.

    The strictly design-based case can, by bad fortune, yield "unrepresentative" results, in a sense, but all three methods yield results for which standard errors can be estimated.

    The strictly model-based approach is a nonprobability sample, or at least it can be, but with regression used for estimation ("prediction") of missing data. This requires regressor data on the entire population, which may not be as difficult as it sounds. For the model-based classical ratio estimator, the regressor data for cases not in the sample can be just a lump-sum, and still obtain variance estimates. For example, if you wanted to know total damage in dollars during a hurricane season, but only had a sample of respondents saying what their damages were and what they paid for a certain prevalent building material, the former would be y and the latter x in (x,y) data points for the sample. If you had the total for all x in the area, X, the value of all of that building material sold, perhaps through some administrative records, then you might do well. You have to consider your situation. Stratification is very important. Each regression model should only be applied to data that follow that given model. Say, you may want to stratify farms and residences separately in the 'example' above. It would be very important to stratify differently, maybe even by a different building material, if say bricks were used one place and wood somewhere else. Maybe plumbing supplies could be another regressor.

    But most nonprobability methods are practiced without regression, and subject to unknown bias and variance. The bias that may be a concern that prompted use of that Dillman data collection method is a big concern in such cases, where nonprobability sampling is used without regressor data. Results could be very misleading.

    Now if your mail survey in your question was a random, or better, stratified random survey (for random, you can do "post-stratification, " and for response rate problems, you can use "response propensity groups"), then you are in business, but you need to at least estimate standard errors. As for the convenience sample, I agree with Seda that this is not something you want to combine with your mail survey. You may find it useful to compare descriptive statistics between the surveys, but I doubt that it would be helpful, except that it might give you an idea for something else you might want to study.

    If your mail survey was a census, you may still want to look into response propensity groups for weighting to deal with nonresponse.

    Finally, comparing your convenience sample survey results for students, stratified by the age and other factors you mentioned, to the mail survey (sample or census) of that stratum, might give you some idea as to whether or not the data collection instrument itself produces bias in the answers. But this would be rather subjective, from what I think I understand of your project.

    Hope this helps.

  • Mahan Jahanbakhti added an answer in Abaqus:
    Pinching effect of cyclic loading in ABAQUS

    how can i see pinching effect of cyclic loading in ABAQUS for a i-shape beam to i-shape column connection?

    Mahan Jahanbakhti · Khaje Nasir Toosi University of Technology

    thanks for the tips. I want to model a welded beam to column connection in abaqus, applying AISC cyclic loading and see pinching effect due to local column's flange buckling.

    may be I have to use initial imperfection in my modeling! could you please help me?

  • Manmatha Mahato added an answer in XRD Analysis:
    What are crystallite height and diameter values in XRD analysis?

    I have performed XRD analysis for my oil fly ash samples. I have the results and I want to make a tabular representation of these data such as inter-layer spacing (d), crystallite height (Lc), crystallite diameter (La) values to compare with natural graphite. 

    But I don't see any thing mentioned as Lc or La in my result sheets. I've got the 'd' values and there is a term 'Crystallite size' with values around 13-14 angstrom. 

    I don't understand, which value is this? Is it Lc or La? Plus I would appreciate if you can show me some different analysis with XRD results for my thesis. 

    Thank you very much for your time!!

    Manmatha Mahato · IIT Kharagpur

    Not crystallite height, it may  crystallite size,,,,,,,,,,,,,,,,,

    Use Scherrer equation or.................

    Peakfit software,

  • Cytomophometric analysis of Leishmania donovani?

    Is there anybody experienced with promastigote-like strctures in L.donovani patients?

  • Yingyu Cui added an answer in Necroptosis:
    Apoptosis or Necroptosis?

    When the cell undergoes ATP depletion, apoptosis cannot occur and the cell dies by necroptosis (programmed necrosis). In TNFa -induced necroptosis, activation of Complex IIb ( Ripk1 / Ripk3 ) kills the cell without ATP depletion (I think). If in addition to activation of TNFa pathway another pathway that induces apoptosis is active, how the cell decides to die?

    Yingyu Cui · Tongji University

    Hi, Herman

    Under the situation as you discribe, some cells of the cell pool may perform necroptosis, while some ones of the pool will perform apoptosis, and still others may remain alive but can't divide any more. As for one cell, when it receives death signals from two different origins by different signal pathways, the result may depend on which signal is stronger, which pathway is shorter. Just for reference. Best!

  • What did the placebo mouth spray contain?

    I am assisting in some research which will need a placebo mouth spray to compare to a nicotine mouth spray and was wondering what the best placebo would be. The method section states that capsaicin was added instead of nicotine but to what base solution? How was the mint flavour mimicked? What concentration of capsaicin was used? Any input from other researchers who have used similar placebo procedures would be welcome.

    Thank you,


    Hi Jasmine

    SPRAY III study participants will be randomly assigned (like flipping a coin) to receive either Sativex® or placebo (a mouth spray that does not contain any active medication). There is a 50 percent chance of receiving Sativex® and a 50 percent chance of receiving placebo (a mouth spray that does not contain any active medication).For more please read at the following links and attached paper.

    Have a nice day

  • What are the characteristics of distant large earthquakes?

    The distant large earthquakes located more than 100km far from the sites have any characteristics which influence the ground motion and response spectra of these sites?

    Ali Akbar Shaikhzadeh · Ferdowsi University Of Mashhad

    I think I could not explain well. 

    You know that earthquake is a combination of waves with different periods, that is every wave has a period and thus a frequency (T = 1 / f). One of the main characteristics of near-fault earthquakes is that they have waves with long period (low frequency). These low frequency waves act like pulses and even some isolators like FPS can not mitigate the base displacement and super-structural acceleration due to these pulses and result in amplified seismic responses.

    However, far-field earthquakes do not have such characteristic, that is they do not have low frequency waves.

    Wish it helps.

  • Manohar Sehgal added an answer in CO2:
    Is there an efficient CO2 filter that doesn't eliminate CO?

    I would like to analyse CO using a mass spec however i do have CO2 gas present. So I'm interested in efficient and reliable CO2 filters that eliminate CO2 without affecting CO. Other suggestions are also welcomed. 

    Thank you!

    Manohar Sehgal · DAV College Jalandhar

    After having surveyed literature to the best of my ability, I , humbly, propose two references for your perusal.
    [A]CO2(g) adsorbs while CO(g) leaves:
    Microporous and Mesoporous Materials
    Volume 156, 1 July 2012, Pages 217–223
    Pls. find its resume as:
    For a specified purity of CO2 exiting the packed bed adsorber, the best CO2 removal performance is obtained with CuBTC.

    [B] CO(g) adsorbs while CO2(g) leaves:
    1997, Volume 3, Issue 1, pp 27-32
    Pls. find its resume as:
    Although zeolites such as NaY and 13X adsorb CO2 much more than CO, the adsorption amount of CO2 and CO can be reversed if the zeolites are modified with CuCl. When zeolite NaY or 13X is mixed with CuCl and heated, high CO adsorption selectivity and capacity can be obtained.
    ------------------------------------------------------------------------ Using the adsorbent, a single-stage 4 beds PSA process, working at 70°C and 0.4 MPa to 0.013 MPa, CAN OBTAIN CO PRODUCT WITH A PURITY>99.5% AND YIELD >85%.

  • Mohamed Awad Dadamouny added an answer in AFLP:
    What is the best DNA extraction methods gives a good result with AFLP?

    AFLP requires a highly purified with high quality DNA. In case of plants which are rich in polyphenols and polysaccharides, what is the best methods for DNA extraction?  

    Mohamed Awad Dadamouny · University of Greifswald

    Thanks all! I'm working on genomic DNA extraction from silica-dried leaves for a plant has a high content of phenolic compounds and polysaccharides. There is no problem with the young seedlings of this plant. For the trees, I found the following problems:
    1. For the first extraction, I got a yellowish DNA due to the phenolic compounds even I'm using 2 % CTAB buffer plus urea, boric acid, and Mercaptoethanol. I was precipitating organic compounds with chloroform Isoamyl (24:1) 2 times.

    2. For the second extraction, I tested phenol: chloroform Isoamyl (25: 24:1) and Ammonium acetate but I got a gelatinous pellets. AFLP reaction with this methods wasn't bad but I'm looking forward better results. Based on your great experiences, any other method can be used. 
    Thanks a lot for your interest!

  • Does anyone know the permissible limit of plants heavy metals/micronutrients?

    Several micronutrients such as Cr, Mn, Fe, Cu,Zn, etc. constitute a small fraction of our diet and play animportant role in metabolic processes. Their excess or deficiency may disturb normal biochemical functions of the body.

    Moududur Rahman Khan · University of Dhaka

    Sorry. I meant an individual's average intake of toxic minerals over a reasonable period of time, not the population average. This average also excludes an accidental or deliberate exposure to a megadose on a single day, which should be handled differently.

  • Harish Vuyyuru asked a question in Clerodendrum:
    What would be the best method for separation and purification of Diterpenoids components from plant extract?

    May I know hat would be the best method(HPLC/TLC/CC) for separation and purification of Diterpenoids components from Clerodendrum eriophyllium plant extract? Also is there any generalized protocol?Am completely new to secondary metabolite research area

    Thank you

  • Which one i should use for face recognition MAT lab or Sci lab?why?

    i am doing project for face recognition and i was planned to use mat lab but higher ups tell me to use Sci lab i don't know anything about sci lab if anyone know about it please share with me and sci lab better than mat lab please inform me

    Rajasekar Kalisamy · Sri Krishna College of Engineering and Technology

    thank you, but i want to know more technically about sci lab that is some says that sci lab tools are constraints and costly

  • Paul R. Yarnold added an answer in Survey Analysis:
    Is it correct to map the "means" into "equal intervals" to facilitate the interpretation of the survey results?

    I saw some researchers who used this formula: (n-1) / n, where n is the maximum number in the used scale. For example in five-point Likert scale, n is equal 5. So, the interval size can be calculated as 0.80. I just need a confirmation or precise evidence 

    Paul R. Yarnold · Optimal Data Analysis LLC


    It is clear that ipsative normalization is essential in analysis of longitudinal data, regardless of whether the study is sample-based or a single-case study. I haven't yet considered or investigated the use of an ipsative transformation to normalize responses to different items made by individuals in a sample-based study. Your question has peeked my curiosity. The following article describes and illustrates the approach for a sample-based longitudinal study (citation 3 in my prior post demonstrates this for a single-case longitudinal study). Rather than ipsatizing a series of responses made by an individual on a single measure, the approach is to ipsatize a series of responses made by an individual on different measures with a common domain (as was done in citation 3). The raw ratings of each individual would be replaced by the corresponding ipsative rating.


  • Sardar Ali asked a question in MATLAB:
    I want to wite a program for low density parity check codes in Matlab, and trying to analyse SNR and BER. But I don't know from where to start with?

    Forward Error Correction

  • In your institution, what are the strategies and/or approaches in generating funds for your research projects?

    The common problem being encountered by universities and other institutions in developing countries is the lack of funds to conduct research projects.  Financial deficiency results to lack of incentive for researchers, absence of high-end technologies, instruments and materials for laboratory works as well as poor dissemination of outputs.  As a consequence of a poor monetary support, research outputs seldom find its way to globally-recognized and standard scholarly journals.  Thus, without a reasonable amount of funds, research has become an exercise of futility and mediocrity.

    Ade Olaiya · University of the West of England, Bristol

    Doctoral research students at the University of the West of England can apply for a limited number of bursaries offered by the university. Research funding may also be applied for from subject  specific research councils e.g. ESRC and AHRC in England. Furthermore,  funding can be sought from other government sources in the form of student loans and grants for a limited number of disciplines e.g. law and architecture.

  • I. L. Zhogin added an answer in Physics Theory:
    Irrespective of whether (human) beings model it, can the Universe escape self-reference or logical circularity?

    Will this be the final incarnation of this question?

    My purpose in asking these questions is to motivate the kind of physical theory that accepts that Physical Laws are part of The Universe, as opposed to standing outside it. And that rules governing The Universe must stem form The Universe itself. Otherwise, we should be asking: Where do the Physical Laws come from?

    I. L. Zhogin · Bourevestnik, Inc

    Well, it seems that the Universe should simply be a sort of (nontrivial) perpetuum mobile (i.e., with trivial solution being unstable).

  • Barbara Sawicka added an answer in Tamil:
    What are the steps taken in your country to control the ragging in the Educational institutions?

    Dear Professor, RG Members, friends,

    Ragging in India is a damaging form of interaction of the seniors in college or school with the juniors, newcomers or first years. it is not an initiation. It involves insults (simple or suggestive sexual, sarcastic and even physical), running errands for seniors, and many other complex activities. Highly reputed Indian colleges have a wistful history of ragging especially Medical colleges. It has become increasingly unpopular due to several complaints of serious injury to the victims and strict laws regarding ragging. Ragging is now defined as an act that violates or is perceived to violate an individual student's dignity.

    Tamil nadir is the first state in India to pass an anti ragging ordinance and later this ordnance was formalised as the Tamil Nadu Prohibition of Ragging Act, 1997. Supreme Court orders a National Anti-Ragging Helpline was launched by the Indian Government.

    Dr. Shanmugasundaram P

    Barbara Sawicka · University of Life Sciences in Lublin

    In my country there is no such phenomenon among students. Similar behavior meets while in the army as a "wave", although it is prohibited.

  • How is the protocol to use KN-62?

    Inhibition of calcium/calmodulin-dependent protein kinase II.

    Nathaniel Weygant · University of Oklahoma Health Sciences Center

    Hi Ximena,

    Are you going to be treating cells with this drug? What kind of analyses do you need to do? Typically you would dissolve the drug in a carrier solvent and treat your cells at different concentrations and/or for different lengths of time and then perform various analyses.

  • Irfan Ali added an answer in FC:
    What is basic difference between ZFC and FC curves? and what type of information we can be obtained from these curves?

    My question is, what is basic difference between ZFC and FC curves? and what type of information we can obtained from these curves?

    Irfan Ali · University of Science and Technology of China

    Dear lakhan

    Well thanks a lot for such a detailed guide line.

  • Eric Nallon added an answer in Bioinformatics:
    Python modules: LibSVM or SciKit-Learn SVM?
    I'm going to do SVM using Python 2.73 and I wanted to know if anyone has used these packages before and what their experiences were. What are some of the strengths/disadvantages of each one? Also what would you suggest as far as anything that does optimization of the parameter space?
    Eric Nallon · RDECOM The United States Army

    Sklearn has a GridSearchCV function which accepts a classifier and its parameters (e.g. C and gamma for rbf SVM) and then performs exhaustive type search to produce the best classification.  You can then get the parameters that produced these results.