Q&A

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

Browse by research topic to find out what others in your field are discussing.

Browse Topics

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • Ralf Gollmer added an answer in Multiobjective Optimization:
    Model : weighted sum multi objective.Can I use one of the objective in a constraint ?

    The objective of the model is minimizing cost and there is a service level constraint in which the fill rate should exceed a specific target service level.I am trying to convert this model into weighted sum multi objective model with minimizing cost and maximizing fill rate as objectives. I need the service level constraint badly in my model. My question is can I use the fill rate in the objective and also in the service level constraint ?

    Thanks,

    Prasanna

    Ralf Gollmer · University of Duisburg-Essen

    Hi Yihua Li,

    I do not get your pint, why shouldn't the inclusion of the constraint heöp to solve the specific problem? If a minimum level HAS to be attained, the not the full Pareto front is of interest, but only part of it. Exactly that part is feasible wrt. the additonal consstraint.

    Do you also think that the epsilon-objective  method with bounds on the objectives and optimization wrt. to one of these doesn't help to get Pareto-optimal solutions? This method (in theory) is even possible for non-convex problems - but to find non-supported efficient points the feasible region reduces to just one point and is not stable e.g. wrt. rounding errors.

  • Glen L Sumner added an answer in SCD:
    Could anyone please recommend an informant measure for SCI/SCD?

    I am aware that at this early stage informant reports are not that helpful but I am hoping to add it to my battery to explore their impact further.

    Glen L Sumner · The University of Calgary

    Could you clarify precisely what you mean by "informant measure"?  Are you  referring to ascertainment of SCI/SCD or something else altogether?

  • Rami Ben Haj-Kacem added an answer in Human Development Index:
    What is the most appropriate index to use when referring to the poverty levels of a country's population?

    I am discussing issues around fisheries management in Mozambique, in a manuscript and would like to put these issues into context by providing some basic information on the economic status of the country as a whole (and thus of its poorest communities).The UN Development Programme's Human Development Index is one possible way to do this, but are there others that are more relevant or politically correct?

    Rami Ben Haj-Kacem · University of Carthage

    The common index used for discuss the economic status of the country regarding the  poverty level are the Headcount, the Gini index and the HDI.

  • Mutaz Omer added an answer in Lenses:
    What are the best DSLR cameras in the market that have the best lenses in terms of lens distortion (minimum distortion)?

    Camera Calibration

    Lens Distortion

    Mutaz Omer · University of Khartoum

    Hi Ahmed

    I'am interested in surveying measurements ( Close range photogrammetry)

  • Michael P. Weinstein added an answer in Climate Change:
    Is it time we shift emphasis from technological solutions to climate change & focus on the 'Human Dimension'?

    Is it not obvious that nature can heal itself, if only left alone, and it is we humans who need regulation? Many natural parks managers do just that; seal off the area from human interference to let nature heal and recover. It is classified as 'Strict Nature Reserve"by IUCN. Complacency and inaction are not advocated here, as many have misunderstood, but the shifting of focus from technology to the human being. As technology is no match for human greed, isn't introspection & restraining ourselves more relevant than developing more technology, which caused the mess in the first place, by making it easy for a few to consume more? Since technology is only a short term quick fix which fails after a short time, isn't the real problem our addiction to material consumption & our lack of understanding about human nature? Isn't developing more technology sustaining the addiction instead of correcting it, leading to more complex problems later on, needing more complex technological quick fixes like higher drug dosages, more ground troops & equipment, (along with their debilitating side effects) in the future? Isn't this the vicious addiction circle we are trapped in? As researchers, do we merely buy more time with technology OR go to the very root of the problem, the human being?

    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?

    " Our studies must begin with our selves and not with the heavens. "-Ouspensky

    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.

    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 by now, given the amount of money plowed into finding such 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!

    The Mind is the Final frontier.

    Michael P. Weinstein · Montclair State University

    Antonio

    It was quite impassioned.

  • Morton E. O'Kelly added an answer in E-Mobility:
    Is there an assumed relationship between successes of E-bikes and E-car market?

    Does anyone know about studies or discussions about an assumed interrelationship of two-wheeler E-mobility (E-bikes) and four-wheeler E-mobility (E-cars)? Are there suggestions or hypotheses that the success in the sector of E-bikes forecasts possible future success of E-cars?

    Morton E. O'Kelly · The Ohio State University

    Both shared means of transport are a good addition to the spectrum of mobility options. Experience here (in Columbus OH) suggests that the two means of transport may have different end users -- bikes more for recreation and social, whereas cars can be used to fill in some needs in the journey to work.

  • Katie A Clark added an answer in Arabidopsis:
    How we can differentiate col and ler ecotype of Arabidopsis by PCR?

    How we can differentiate col and ler ecotype of Arabidopsis by PCR?

    Katie A Clark · Pacific University Oregon

    I also used SSLP markers for a mapping population of Col and Ler plants.  Since molecular markers are co-dominant, you can easily determine if a plant is homozygous for Col, heterozygous or homozygous for Ler at a specific loci.  Is your DNA from plants that are just one ecotype or the other?  If you are just verifying the origin of your samples, I would think that two markers is enough.  If you are concerned that your plants may have been cross-pollinated at some point, then you should check more markers.

  • Alvah C Bittner added an answer in Sample Size:
    What is the minimum sample for a one group pretest posttest experimental research?

    - is sample size of 15 is sufficient for an in-depth intervention (for one group  pre test- post  research design ?

    - As i am providing intervention through a particular method which permits the maximum number of 15

    - It is for PhD 

    - Can i supplement the information with some case studies ?

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

    time-series -balanced for residual effects-- with an N=1 with no power concerns. You will find such experiments discussed in texts and articles devoted to N=1 research.   In classical perceptual research, one subject would serve as Experimenter and another Observer  for one series and then reverse roles for another [N=2 providing for assessment of the generalization of results].  Both of these are interesting as they can accommodate some reactive effects (e.g., learning and fatigue).  On the other extreme, you may find that you need to evaluate the effects with a control group.   This usually ignores individual differences, but you may be able to give an outcome measure assessment to all -- at enrollment -- then randomize into say 8 Exp and 7 Control, but then apply the initial measurement as a covariate (to control for individual differences and increasing power0.  Subsequently it then might be possible to consider applying the intervention effects to the control group.  Certainly pre-post but results paralleling those in the original experimental -control  comparison would be supportive.   The point is that there may be alternatives in design, and measurement, that will provide the means for your study with 15 subjects total -- and a consultant may be remarkably helpful.

  • Amaechi J. Anyaegbunam added an answer in Bifurcation Analysis:
    Can anyone help me solve a problem of AUTO-07p; to get frequency responses of the following Duffing equation with a softening nonlinearity?

    AUTO can be used to study the continuation of periodic solutions of the system of ODEs.
    When I study the frequency response of the following Duffing equation by using AUTO.

     
    d2u/dt2+2*xi*omega0*du/dt+omega02*u+epsilon*omega02*u3=F*cos(omega*t),

    epsilon=-0.1, xi=0.01,F=0.1,omega0=1


    I found that if epsilon>0 or epsilon<0 but close to zero, say epsilon=-0.01 , it is easy to get the frequency response. However, if epsilon is very small, say epsilon=-0.1 , there will be abnormal termination. I have adjusted DS, DMAX, NTST, NCOL, NMX in the constant file as well as the computation direction, yet still no reasonable results obtained. I wonder whether AUTO-07p can be used to study the frequency response of the strong softening nonlinearity. How can I derive the frequency response using AUTO-07p if epsilon=-0.1 .

    Amaechi J. Anyaegbunam · University of Nigeria

    Hello D.F. Cui

      The forced vibration of a damped Duffing oscillator is a problem that has been extensively studied in the literature. I have investigated this problem using Runge-Kutta 4th order integration scheme and discovered, in agreement with previous research that the amplitude response of the Duffing oscillator with exciter frequency  depends primarily on the following: (i) the initial conditions u(0) and u'(0) where the prime is used to denote time derivative (ii) the magnitude F of the forcing function (ii) the value of epsilon. In my studies abrupt termination of solution occurred due to overflow error because the iteration refused to converge but instead the magnitudes of u and u' grew without bounds.The The response of the Duffing system can be described appropriately as chaotic because the reasons for instability of the iteration process are quite complex and not readily understood. When epsilon is negative I have obtained admissible solutions for epsilon = -.0.4 provided F is small. For the parameters you specified namely epsilon =  -0.1, xi = 0.01,F = 0.1,omega0 = 1 the amplitude-frequency response is as follows

    Umax   0

    omega     0        0.1    0.2     0.4     0.6      0.8     1.0       1.5       2.0      3.0               

  • Rita B. Santos asked a question in Plant Cell:
    What's the best loading control in western blot for plant cell media samples?

    Want to demonstrate that my protein concentration is higher in some samples despite sample having the same total soluble protein. Does anyone know a good loading control for plant cell media samples?

  • Sudev Naduvath added an answer in Astrology:
    Can a scientist has two faces - realistic and superstitios?

    Several scientists conducting researches on clone or on space or sea are found to knock the door of astrologers. How do you see it?

    Sudev Naduvath · Vidya Academy of Science & Technology

    There are some scientists who are realistic as well as superstitious some times. We can see a lot of scientists who are religious and practice religious rituals even if they are baseless. I have experiences with some scientists who wear certain particular colour dresses with a belief that that colour dresses will bring fortune and good results in their research or activities. I have also seen many scientists who believe in astrology and numerology.

  • Rami Ben Haj-Kacem asked a question in Quantile Regression:
    What are your recommendations in the censored quantile regression?

    In the case of a censored quantile regression, the choice of the quantile is important and the estimation results depends on this choice. According to your expertise, what are your recommendations about the choice of the quantile and the interpretation of the estimators.

  • Waleid Shakweer added an answer in Molecular Biology:
    Did any body produced GH in bacteria DH10B?

    molecular biology and microbiology

    Waleid Shakweer · National Research Center, Egypt

    Thank alot Brian Bower for your contribution to answer my question and as I far as I know, The GH protein is not toxic for DH10B cells.
    I used an expression vector contains CMV promoter

  • Eduardo I. Faúndez added an answer in Scientific Communication:
    Why do researchers in the tropics not support journals published in the tropical regions of our world?

    It is often the case that  researchers who work  on topics unique to the tropical regions of the world try to publish their work in journals based in the developed temperate countries. This frequently leads to their papers being rejected on grounds that they are only of regional interest. Hence, its best if we support our own regional journals so that these journals will become better known and of high quality by having good papers submitted and published in them.

    Eduardo I. Faúndez · North Dakota State University

    That's true however years ago you don't have as many publishing options as today; and the whole market situation (i.e. granting, publishing costs, etc.) was different. Additionally there was a visibility factor, that today with open access and internet is totally different. In other words, you may say no significant changes in Journal selection or preference; but the reasons of these selections are not the same

  • Faranack Nader Benz added an answer in Questionnaire:
    What can affect the results of a questionnaire in different cultures?

    When we use a questionnaire in different societies, its results and answers are different too.What can effect on the results of a questionnaire in different culture?

    Faranack Nader Benz · Niagara University

    If the questionnaire is in the society's language (no language barrier), the factor of education stays ahead of two considerable variables of gender related issues, and the belief system. On the other hand, if the questionnaire appears to be in a different language, the linguistic familiarity (corralations & confidence) could be a precedence element over the education, gender, and religion.   

  • David Wolovsky added an answer in Curriculum Design:
    Does anyone have any useful information for online curriculum design?

    Dear all,

    I a interested in learning how to design an online class and would like to know practical steps to creating one.

    Thank you,

    Mary Freeman

    David Wolovsky · Wesleyan University

    This is pretty good and free. http://blog.teachery.co/how-to-build-an-online-course/

  • Shawna Warehime added an answer in Trout:
    Does the size of a fish greatly affect the amount of cortisol that is released into the water?

    I am looking at cortisol levels in rainbow trout (as an indicator of stress) after being exposed to different anesthetics for immediate release in the field. However, the size of the rainbow trout we received were much smaller than we had anticipated. The fish are about 7.62 centimeters (three inches), when we needed about 12.7 minimum (five inches). Therefore, what I am wondering is that since they are so small, will they release enough cortisol in the water for me to detect it?

    Shawna Warehime · Eastern Washington University

    Thank you!

  • Wolfgang F. Schwarz added an answer in Cultural Anthropology:
    What text would you recommend as a basic introduction to the concept of culture as a system or whole?

    I need to sugest a reading for somebody who is not anthropologist nor student of anthropology, to understand that elements of a culture doesn´t have intrinsic meaning or value, but that it stems from the system and that every element is related to every other element. I don´t want to recomment a big book such as "Man and his works", but an easier reading. I use to have a bad time to remember what text helped me to understand this basic ideas that now are common anthropological sense for me, but are not obvious for other people. Any sugestions?

  • Artur Burzynski added an answer in Bioinformatic Tools:
    Softwares used for cluster analysis of protein sequences? Tool which can blast protein seq. against each other and provide e value as a output?

    I have 300 protein sequences which encodes laccase gene. Sequences are from different bacteria and fungi. I want to do cluster analysis to see which laccase sequences form clusters and how many clusters forms. Is there any software or tool that can do blast of all the sequences against each other and generate e value or something meaningful number which I can use to do cluster analysis in Cytoscape like softwares.

  • Hugh Lachlan Kennedy asked a question in Pain Threshold:
    How does the 'maximum achievable' heart-rate change as cardiovascular fitness increases?

    Let's say a person undertakes a program of high-intensity interval training (HIIT) on an exercise bike, with a heart-rate monitor, in a gym. This program involves 30 min sessions every day. The objective of each session is to reach the maximum achievable heart rate at the end of the 30 min period. By 'maximum achievable' I mean the rate at which a highly motivated individual is able to reach (while being yelled at by a trainer, for instance). I think this limit is effectively determined by the person's ability to tolerate pain/discomfort - it would be around say 85% of a person's 'maximum' heart rate, which is determined using the 220-age_in_years rule-of-thumb. At this limit the person is a 'mess' (lost all inhibition, sweating profusely, short of breath, grunting involuntarily, etc.).    

    My question is - How would this 'maximum achievable' rate change as the program progresses and as the person (who is already reasonably fit) becomes fitter? Would it increase or decrease? And what determines this discomfort/pain threshold anyway, if it is not heart rate? Furthermore, what is the significance of the 'maximum' heart rate if it is not reachable/achievable in reality?   

    Thanks in advance for your help.

  • Emily Forsberg added an answer in Insecticide:
    Does anyone know the effect of insecticides on hyperspectral "profiles" of plants?

    Specifically, my Russet Burbank potatoes were accidentally infected with thrips and were recently sprayed with Overture 35 insecticide, twice. My latest hypserspectral reflectance measurements show a rise in reflectances for both controls and inoculated plants, when I should expect a drop in reflectances for my inocluated plants. Has anyone else seen this after using Overture, or know of research articles examining the effects of insecticides?

    Emily Forsberg · University of Idaho

    Agreed, Thanks Timothy.

  • Jere Charles Harrison added an answer in Plasma Etching:
    How to reduce the bubbles on SPR surface which is coated on polymer substrate?

    Hello everyone,


    I tried to coat 15um of SPR on silicon wafer with 2in in diameter. The SPR is used as an etching mask, for a plasma dry etching.

    The SPR isexposed under broad UV light (365nm) with 500 mJ/cm2 and bake at 115°C after a waiting time of few hours.

    Lot of bubbles appear during the plasma etching. this may be due to the plasma UV light.

    Does anyone have a solution for avoiding that kind of problem ?

    Thank you in advance.

    Jere Charles Harrison · University of California, Los Angeles

    If the problem is with micro-bubbles or dissolved gas in the photoresist:

    I've addressed similar problems when pulling hard vacuum (<1mTorr) by incorporating a vacuum bake step in my process.

    For serious photoresist bubble problems, such as spinning resist over high-aspect ratio topology, I use a vacuum (not bake) step between pouring the resist and spinning. Pulling 30 mTorr vacuum on the sample for 10 seconds will expand all of your bubbles and float them to the surface. The subsequent spin will remove them from the wafer. The downside of this approach is that you need to pour significant thickness of resist, which is quite wasteful. It is very effective, however.

  • Alberto Leguina-Ruzzi added an answer in Stromal Cells:
    Is there a known stable factor for standardizing supernatant?

    We are culturing different types of primary stroma and we want to use the supernatants in some experiments. But how can we equalize the supernatants? For westernblotting you can use b-actin, is there a stable factor in supernatant that we can use to compare to? All ideas and suggestions are welcome!

    Alberto Leguina-Ruzzi · Pontifical Catholic University of Chile

    Usually around 60-70ug quantified by bradford or BCA, that would be around 40uL, it depends. The BSA loading control works as a standard westerblot using anti BSA antibodies, there are several comercial ones with very good results.

  • Reginald L. Bell added an answer in Reputation:
    Do you have any experience or explanation regarding continued gradually decrease of reputation rate ?

    I am faced with continued decrease of my RG without any explanation,

    taken into account growing downloads,upvoting questiones,new questiones and participation into discussiones- etc – all components required for RG calculation ? Thank you in advance.

    Reginald L. Bell · Prairie View A&M University

    Colleagues,

    I agree with the above accounts that journal (Thomson Reuters listed journals) impact points and constant activity answering questions are what sustains one's score. I checked out a few of your RG Scores and found that beyond a certain threshold, RG Scores level off, and there is precisely no variation in the scores after a RG Score of 54.0 is achieved; there is a certain point of academic success which is the same for all members regardless of their contributions.

    In this chain we find six RG Scores from contributors to this discussion, but the meaning is mostly at the lower end of the score spectrum and no variation exists at the top.

    The six scores are followed by the statement, "Your RG Score is higher than 00.0% of RG members'. Publishing in the Thomson Reuters list of journals is the fastest way to increase and hold your RG Score.

    For example, in this discussion chain, RG Score = higher than % of RG members'

    14.82 = higher than 55%...

    17.04 = higher than 62.5%...

    20.04 = higher than 70%...

    37.26 = higher than 95%...

    54.00 = higher than 97.5%...

    105.68 = higher than 97.5%...

  • Carlos Reynoso added an answer in Employee Engagement:
    Why is there low ROI from employee engagement programs?

    While much is expected of Employee Engagement initiatives, i sense that the ROI is doubtful, at best low.

    Of the many possible reasons for this, one major aspect which i think we miss out on while strategising/devising Engagement,  is the lack of wemloyee involvement in devising enagement programs. We need to customise engagement to the employee expectations. The offerings may be categorised broadly into a few buckets but the exact measures within each bucket needs to be democratised / customised

    DO you think this could be a research topic ?  

    Carlos Reynoso · Universidad Popular Autónoma del Estado de Puebla (UPAEP)

    Sankalp Hi:

    Most of the times, the company don´t think in the person, they think in the organizations results.

    In other situations, when the recruit is in the same way of the employees that is more easy to obtain ROI.


    And another idea is, the program of recruit will be changed constantly because the future worker will constantly change.

  • Adel Hamada added an answer in Transition Metal Complexes:
    What XRD software is used to index unknown compounds?

    what the XRD software used to indexing of unknown compound?. I prepared anew transition metal complex and i want to deduce the structure of its whether cubic or tetragonal or hexagonal etc... What is the XRD software used for this purpose?

    Adel Hamada

    dear sir

    many software

    as

    mercury CCDC

    Diamond

    Ortep,......

    WingX

  • Rolando Biere Arenas added an answer in Sustainable Urban Development:
    Does anyone have solid evidence for institutions that prove to be beneficial for realizing sustainable urban waterfront areas?

    I am preparing to study the impact of planning policy instruments on the behaviour of private sector stakeholders in the sustainable development of urban waterfront locations.

    Rolando Biere Arenas · Polytechnic University of Catalonia

    Hi Erwin:

    In general you could look articles or books of Rinio Brutomesso, for example “Waterfronts. A new frontier for cities on water” (1993) or "Complexity on the urban waterfront”, in “Waterfronts in Post-Industrial Cities” (2001), among others.

    At the same time in the Portus Journal (http://portusonline.org) you will find interesting articles concerning your specific question.

    Considering your last clarification, maybe you could read about the economic information in Forum zone in Barcelona, developed in the framework of The Forum of Cultures 2004.

    Other example that involve a different public and private institutions in the process is the Liverpool experience, including the Liverpool Waterfront Business Partnership http://www.visitliverpool.biz/industry/industry-network-contacts/liverpool-waterfront-business-partnership

    Best regards.

    Rolando.

  • Abhishek Shrivastav asked a question in Simulators:
    Is anyone using the Spectracom GSG-5 or 6 series GNSS simulator in a real time environment to simulate GPS satellites?

    I have been working on a GNSS Simulator from the past few days and would like to simulate a position in a real time mode along with RTK corrections from the simulator itself (Virtual) and an existing Base station. Would be great to find someone who has already played with the simulator.

    Thanks

  • AR Reddy asked a question in Antennas:
    What is antenna modulation ?

    What is antenna modulation ?

  • Francesco Pomponi added an answer in Pricing:
    How can I model the pricing indices for specific project type within uncertainty conditions?

    best modelling approach for uncertainty of pricing indices of construction project

    Francesco Pomponi · University of Brighton

    Dear Abbas,

    I agree with Floris that more specific help could be given with more specific details. Depending on which data you have, something you might also want to consider is Monte Carlo simulation.

    Best wishes,

    Francesco