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.
- What are steps of a national policy development process?
I need some information on the steps that a policy maker needs to take in developing a new national policy, say for solid waste management. I know this is a specialized expertise, still there are experts of solid waste management, for example, in developing the policy.
Appreciate your thoughtful advice or information on the process of initiation, consultation, drafting, and finalization. What is the format for a policy and what generic clauses are essential in a policy?
Read the following articles. A sure it will be of help to you. www.unep.org/.../Waste%20Management/UNEP%20NWMS%20English..., www.unep.org › ... › Information Platform and www.epa.gov/climatechange/wycd/waste/downloads/overview.pdfFollowing
- Are there any available clusters for research?
Ii want to conduct some researches in distributed-big data. I wonder if there are any available clusters ,with online access ,like Amazon?
Indeed Amazon is a good option for big data analysis -but I don't like its changing method ..
If you can suggest other options ,either free ,or low cost ,will be great!
- What are the methods that can prove that polymer segments of a block copolymer are attached to each other or it's just a blend of homo polymers?
Normally during synthesis of a block copolymer I will use combination of NMR and GPC to see if I have a block copolymer or not. But is there any method which really proves the segments of a block copolymer are attached to each other? Is it possible by light scattering?
Thanks a lot Rajasekhar Tota. Yes I know about macro and micro phase separation. But I am not an expert on light scattering. It will be very helpful if you can suggest any literature where I can study in some detail about the light scattering phenomenon which you have described.Following
- Is it possible to know the amount of different phases by XRD?
My Sample is Chitosan/PVA/TiO2/ Na-Titanate. I want to know the ratio of TiO2/ Na-Titanate by XRD
It is not a problem? since, I could not able to open your data file in Panalytical format in FULLPROF program. If you have collected cif files then you can create pcr files and weight fractions can be determined by refinement.
More details are available in Fullprof website.
Alternatively, you can use MAUD program and there are many paid programs.
In panalytical software also you can estimate the quanitity of phases.Following
- Do you know relevant learning theories to design social media for learning?
Recently, there is a lot of literature on designing social media for learning. Not clear, however, is if and to what degree these designs are founded on validated and operational learning theories. In short, can we bridge learning theories and social media technologies?
Seeing the unseen learner: designing and using social media to recognize children's science dispositions in action
Ahn, June ; Clegg, Tamara ; Yip, Jason ; Bonsignore, Elizabeth ; Pauw, Daniel ; Gubbels, Michael ; Lewittes, Charley ; Rhodes, Emily
Learning, Media and Technology, 2014, pp.1-31
Social media tools and platforms in learning environments
Bebo White 1945-; Irwin King 1961-; Philip Tsang
- When is it suitable to restart of population in a Memetic Algorithm?
Let's imagine we are using a memetic algorithm to solve the TSP problem. How would you decide when it is suitable to restart the population?
I am using hyper-heuristics to evolve an Memetic algorithm. These generated Memetic Algorithms are compared against a hard-coded one. Now I have been tuning the restart element of these algorithms and I am concentrated to the hard-coded one. I am not convinced I am doing that correctly.
So I am asking how you would tune the restart of a memetic algorithm.
- Why did UV calculations for Napthol derivatives fail to run?
I am working with naphtol derivatives and when I tried to do UV calculations for them, the job was not running and terminated in the beginning itself. Give me some correct keywords to find the same for DFT methods.
I am using gaussian software and the job was not running even the software is not accepting the input. Give me some keywords and input line to be given for ethanol, DMF and diethyl ether solvents.
- Is anyone familiar with collecting ROS measurements with a plate reader?
hello.. please help me with this.
I do ROS analysis with microplate reader as well. i load the dye to cells after 24 hrs of their growth and wash them after 30 mins, add fresh media 1% FBS and then add the nanoparticles which I'm investigating if they cause ROS production. Then I take fluorescence of the plate at different time points up to 48 hours. I was curious to know if this is a good idea? Do the cells have the dye in them for 48 hours and when the cells grow do the new cells also have the dye in them?
Please note, that the dye you use may overload your cells, when you do not wash your cells. That could massively affect your results.Following
- What is appropriate media for MSCs culture?
I would like to know using Alpha MEM having ascorbic acid is good idea or not for mesenchymal stem cells culture. I generally use mice/rat bone marrow stromal cells for MSCs. using alpha MEM containing ascorbic acid induces differentiation of MSCs. I would be happy to know which media is best for MSCs culture.
Hi, we used DMEM/F12 + 10%FBSFollowing
- Why does the data speed of IEEE802.11g and n WLAN systems scale down to lower values if an IEEE802.11b WLAN device is introduced into the network?
What adjustments take place in the physical, data link and IP layers to make this so?
Actually, the answer is slightly more articulated. The 802.11g standard expands the set of transmission rates of 802.11b with new modulation schemes that allow for higher bitrates (if the signal to noise power at the receiver is good enough, of course). Now, in a network with only 802.11g terminals, everybody can understand everything, therefore each terminal (and the AP) can transmit using any one of the available rates. The presence of an 802.11b station, instead, yields two effects.
1) For backward compatibility, all packets that are sent or transmitted by 802.11b terminals need to be modulated with a modulation that can be decoded by these terminals, therefore the new modulations brought about by 802.11g cannot be used. However, 802.11g terminals can still use such modulations. Broadcast packets, of course, need to be transmitted at a rate that can be decoded by all terminals in the network. In this respect, the presence of a few 802.11b terminals in the network does NOT impact much on the transmit rate of the other terminals.
2) The second impact of the presence of 802.11b STAs in an 802.11g cell is that, when transmitting at lower rates, 802.11b stations will occupy the channel for a longer time than what needed by a station that, in the same conditions, could use a higher transmit rate. Since only one terminal at a time can transmit over the channel, the presence of slower terminals will somehow affect the long-term throughput of faster ones, which have to wait longer to get access to the channel. This throughout loss, however, is significant only when the traffic generated by 802.11b nodes is very high, i.e., so that they access very often the channel, which is almost "saturated". In normal conditions, however, this extra delay is basically negligible.
You can take a look at this webpage to learn a little bit more about these aspects:
- Can anybody suggest a way to analyse the intensity of brown colour in histological section?
To analyse brown colour formed by the use of DAB in the histological sections produced at the site of protein localisation done by immunohistochemistry procedures.
Hi! Image intensity analysis: http://fiji.sc/Image_Intensity_Processing ( http://fiji.sc/Image_Intensity_Processing#Getting_intensity_values_from_single_ROI ) . Please, do not forget that mean intensity is NOT a quantitative measure, rather it shows an overall quality of the labeling. Potentially, you may need to compare several images (samples) stained with DAB, you may try to adopt quantitative densitometric analysis (comparing "color weights" on images). You can try adopt the method for DAB-stained samples (http://sciencetechblog.files.wordpress.com/2011/05/measuring-cell-fluorescence-using-imagej.pdf ) if you scale raster images from color to greys and do color inversion (Ctrl-Shift-I , or Edit-Invert in ImageJ) .Following
- Does physisorption always exist at enough low temperature? What's the relationship between sticking coefficient and temperature?
About physisorption in UHV conditions, low temperature is usually necessary, but will physisorption always exist when the temperature is low enough? For example, LN2(100K) or even LHe(<20K) Temperature? What I am specially interested is O2 and CO2 adsorption on oxide.
I know that "The sticking coefficient is a function of surface temperature, surface coverage (θ) and structural details as well as the kinetic energy of the impinging particles.", in case that the latters keep constant, is the sticking coefficient linear dependent on the surface temperature?
A simple estimation of the temperature dependence of sticking probability S(T) can be made by means of the adsorption energy Eads: S(T) ~ exp(-Eads/RT). For physisorbed CO2 a value of 20 to 25 kJ/mol is a good first guess. Usually you can expect adsorption of CO2 at temperatures below 80 K if the sample is exposed to a CO2 partial pressure of 1E-8 mbars.Following
- How do you increase the strength of instrumental motivation of the adult EFL learners?
There are so many adult EFL learners in Saudi universities who study to get a Bachelors certificate in English even with a very bad grade. They think that a personal link with an influential person is much more important than a good grade to get a standard job. They are not interested in co-curricular activities also.
How can they be motivated to learn English as a Foreign Language (EFL)?
I agree totally with Brahim Bouali. He has hit the nail on the head. I would go further, there is often no sociocultural pressure that motivates students to learn English successfully. No matter how hard you try, there is nothing you can do to motivate them. My students all state that they want to learn English but they are not willing to make the effort because society demands Maths, Physics, Chemistry etc. before English. They also associte English with Anglo-Saxon culture instead of as an instrument for global communication.Following
- What is the significance of design point in case of turbo machines ?
How to determine the design point for a turbo-machines. What is its significance,How does it play a role ?
Are the characteristics point and design point the same ?
Turbomachine (example: rotary compressor) is to be desined for maximum effciency. Pressure-ratio is varied with mass flow, in order to find maximum efficiency. Pressure ratio increased with increase of mass flow rate and reaches maximum and beond that it decreased due to losses. A rotary compressor is not to be operated within surging limit, ie when the flow through the compressor is less than a predetermined value, a surge or pulsation begins and air surges fro and to through the compressor instead of giving steady stream in one direction ar . Hence design point and charcteristic points are not the same for a turbomachine.Following
- How to select a suitable material for design chassis for hand truck or trolley?
Anyway to calculate the minimum yield strength needed? Software?
I am doing material selection for designed chassis. I has been thinking is there a way to calculate or generate the young modulus or yield strength needed according to our chassis design for hand truck or trolley in order to select the suitable material for the metal tube? Or is there another way to perform this?
Well, the mechaics of materials theories may be used to determine, e.g., Youngs Modulus or strength requirement for a given loading situation. But it is important to remember that materials selection is a much complex undertaking. Following a holistic approach to materials selection is a way forward, i.e., factors such as weight (density of materials), cost, etc. should be considered holistically.Following
- Is the clock rate of free falling clocks the same?
In a gravitational field of a homogeneous spherical mass M, a sufficiently small mass B, compared to M, is left free in the gravitational field of M at a certain distance H from the center of mass, outside his surface. B gains speed, relative to the center of mass M, because of gravitational attraction. Many small objects like B free fall from different heights or from the same height at different instants.
Every object has an atomic clock on board. Would these clocks have the same clock-rates during the free fall?
A reference, master clock has to be adopted, otherwise the problem is ill posed. Clock-rates are refererred to an atomic clock on the surface of M for example (negligible M rotation speed).
The time elapsed for each body to go from the same starting and ending point counted by the atomic clocks on board is certainly the same (UFF).
Their clock rate should be different, in general, unless they start from the same position and instant. Not because, , the speed of light takes less time to reach the closest, since they are in different positions, but because of the relation between the very small object and the massive object.
I would like your opinion regarding this problem.
There is no such thing as "the influence of gravitational potential on clock rates" - a nonsensical phrase that comes from a misunderstanding of the gravitational red shift in GR.
I don't share this point of view...Following
- Could anyone suggest a kit for MnSOD assay in tissue? I am going to measure mitochondrial SOD in tissue extract. Can anyone suggest a kit that can give me precise results? Also, an extraction method to measure MnSOD only, without Cu/ZnSOD.
You also can have a look to the protocols of Weydert/Cullen published in Nature Protocols. They have nice applications for in-gel activity of SOD.Following
- Do you know a wearable device (wrist or arm) to measure physiological response (ECG and EDA)?
I am searching for a device to measure ECG and EDA. Ideally the device should be worn on the wrist or the arm. I prefer not to use chest band or similar.
There are several devices on the market. It would help to know what scientific question you are asking, e.g. arrhythmia versus heart rate variability and metabolic demand versus blood flow parameters. This will help determine what parameters are best for your purposes.Following
- Is anyone familiar with the removal of DMAP?
I am aiming to protect the amine in 3,3-iminobis dimethylpropylamine by ditert butylcarbonate (boc) and using DMAP as a catalyst. However, when I check the Hnmr, I always see a signal around 8 resonating for DMAP. How will I be able to remove it from the reaction? Also, will the reaction proceed slowly without?
If you're going to do acid washes, you just need to be careful since BOC is acid sensitive and HCl (pKa -9.3) is much stronger an acid compared with TFA (pKa 0.23) which is normally used to deprotect BOC. A wash with aq. weak acid, such as AcOH like Yuvaraj suggest, should be fine.Following
- Terminologies based on ‘observations’ or ‘interpretations of observations’: any thoughts?
When scientists describe (natural) phenomena during oral presentations or in publications, they often replace the description of these phenomena by interpretations of what the phenomena are without having sufficient background knowledge of how and why these phenomena exist. Consequently, exactly the same behavioral expression (e.g. birds approached the feeder) can be defined in different ways (e.g. risk-taking, feeding response, boldness or shyness, exploration behavior, etc..). Should science terminology be based on what is observed or the interpretation of what is observed?
What is the truth in this biology-based world? There are as many visions of the biological world as there are biology-based living beings. How can Greek philosophers make statements about the truth when they never left their garden/ city/ region? Their world was flat or round or what else?Following
- Why does 5' Phosphate come out of binding pocket during equilibration?
While simulating a protein-ligand complex, during equilibration the 5'-phosphate group of it is coming out of its binding pocket. Few water molecules are crawling in. I have performed two independent simulations in GROMACS and NAMD with the charmm36 force-field for the protein as well as for the ligand and observed the similar scenario. What could be the possible cause(s) for this event?
In the minimization - does the ligand stay in place ? What do the energy values look like if you do a selected analysis of the binding pocket only?
Is the binding pocket oppositely charged ?
Few ps means almost at the start. This would mean that either the minimization pushed it out of its energy minimum or the charge complementarity is not working out for you.
How many steps do you minimize for? One way of being sure is not to do any minimization at all. Try this.
If you used VMD, did you use psfgen (script based) or autopsf (gui based). If you used automatic psf builder, it be defaults read charmm27. Look into that as well.
- What could be a reason for Poor PCR product intensity on EtBr gel?
How can the intensity of a PCR product band be increased? it seems to be of 30ng concentration currently
Can there be any tweak in my protocol to help with that?
30 ng is only a few times above the detection limit, so if this is the amount of DNA in a lane, the signal is expected to be weak. It could be further weakened by EtBr migrating in the opposite direction as the DNA, particularly with small fragments that don't bind so tightly to the dye, and this can be solved by adding a little bit of EtBr to the buffer close to the positive electrode. The signal can also be quenched if your desired band runs close to the Bromophenol blue, and this can be solved by using loading dye with less Bromophenol blue (faint blue, enough to see, but diluted enough to stop quenching the signal). Finally, could it be that you can do a few more cycles in the PCR reaction and get more than 30 ng? All of this can be explored, good luck !! :)Following
- How do you calculate the dew point for different tar compounds in different dilution and temperature environments?
I would like to calculate on my own but need help in using the basic formulae.
You can analyse your tar sample using GC-MS and obtain the concentration of each tar compound (aromatics and/or oxygenated). Once you have this information the general tar dewpoint can be calculated by the sum of the partial pressure of each compound considering the concentration of each one. I will try to find useful equations and send it to you but initially you need to know the influence of each compound in your tar, this mean the concentration. Normally tar can be analysed using GC-MS or GC-FID instruments.
If you want to know the influence of the temperature you also need the dewpoint for each compound, then you can predict if it will be in gaseous or liquid form.
Hope this will be useful...I dealt with the same problem. You can also use some of the online tools. For example in the Energy Research Centre (ECN) of Netherlands, webpage there is a tool to calculate this, I will also look for the link to send it to you :)Following
- How can I calculate the zeta potential of particle if I know the particle size, mobility?
How can I calculate the zeta potential of particle if I know the particle size, mobility? Thanks.
These problems have been worked out for quite some time. Rather than me just giving you the expression, I would suggest you consult any text in physical chemistry covering colloidal systems. The book by R. Hunter “Zeta potential in colloid science: principles and applications”, cover this in great detail. I’m sure your university’s library must have this.Following
- Is it possible to analyze for Chloride using ICP-OES (iCAP 6300 radial; Thermo)?
It is highlighted with red color although other researchers said it is possible as long as one has the required wavelength detection technology
I am sending 2 paper for determination of Cl by ICP-OES. The prominent line of Cl is 134.72 nm. The ICP-OES equipment has to give possibilities for determination of elements in this spectral region.Following
- I ask for an applicated method to elaborate a bifonctionnal electrod using a disponible substrate ( either to vitral carbon ) ?
to characterize an bifonctionnal electrod we use substrate + powder oxyde + liant ( elaboration of work electrod), in this aim we use vitarl carbon as substrate, i have not vitral carbon
with what metal can i remplace it ?Following
- How can Scientists and researchers measure Insecticide resistance in insect field populations directly?
The assessment of insecticides efficiency and monitoring insecticides resistance in insect field strains is very important to Scientists and Researchers
You may find some responses in articles from Rodrigiez et al. You can find it here: ww.researchgate.net/profile/Jesus_Avilla/contributions?ev=brs_actFollowing
- I am using HPLC Auto sampler 717 plus and it seems that the syringe keeps on adding certain amounts of the sample, don't know why this is happening?
I just changed the valve(solenoid valve v3).
How much is the loop volume? May be, the volume set in auto sampler syringe is greater than the loop volume!!Following
- Is temperature invariant in Lorentz Transformation?
Arguments supporting or opposing the statement.
In a very general sense the concept of temperature arises from the notion of thermalization of a system. By thermalization I mean the inaccessibility of the microscopic degrees of freedom of the system under observation e.g. no knowledge and control over the microscopic degrees of freedom of a gas of microscopic particles gives the notion of temperature of the gas. As one may notice that this is intimately related to the concept of entropy, which is the measure of lack of information about a system. Now, all these concepts depend on how we coarse grain a system and this is of course observer dependent. Hence, the notion of temperature is not Lorentz invariant. For example, in Unruh effect, the local acceleration of an observer is proportional to the temperature of the heat bath which he feels to be embedded into. Hence, observers with different local accelerations see different temperature. However, as far as my understanding is concerned, all the (classical) physical laws governing any dynamical physical process are observer independent, which forms the basis of general relativity. This would mean e.g. the first law of thermodynamics will remain observer independent (covariant under general coordinate transformations including local Lorentz transformations), although the individual quantities like temperature or entropy may be observer dependent. (I conclude with my sincere apology if I have written something wrong.)Following
- Can someone please explain the mechanism of superoxide dismutase activity assay?
I am currently working on enzyme assays on tumor cell, n the protocol i use for SOD is incubating sample, PMS, NBT and NADH for 90secs at 30C and adding acetic acid + butanol + absorbance at 560 nm. I want to know whether the absorbance of the blank (distilled water instead of tumor cell) should be highest or lowest. Plus whether high absorbance signifies high activity or low activity?and what are the functions of PMS, NBT and NADH?
instead of more or less expensive commercially availabe kits, why don`t you try the method described by Flohè/Ötting. This method works well and is much cheaper.
-> PubMed-ID: 6328209Following