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.
- How can I explain the ESR of cobalt and how many peaks are obtained?
Thanks in advance for your replies.
Co(II) has a nuclear spin of I=7/2 (100%) so you'd expect 8 lines in the ESR spectrum assuming no other spin active nuclei (like P or F) are present.Following
- What is the difference between productivity and efficiency?
There are two firms A and B
Firm A uses 5 units of raw material, 2 units of labor, 3 units of capital to produce 6 units of output in one year.
Firm B uses 10 units of raw material, 2 units of labor, 3 units of capital to produce 10 units of output in one year.
Would I say, Firm A is more efficient than Firm B because it is using less raw material per unit of output with the same given labour and capital; whereas Firm B is more productive that Firm A, because it is producing more output per given units of labour and capital?
Does efficiency pertain to the exhaustible resource(raw material, or time for that matter) per unit of output, where as productivity pertains to economic resources (labour capital, land)?
Productivity refers to the conversion level of inputs into outputs. A process that can produce more output using less inputs is more proactive.
Efficiency in the economic sense mean that things should be done in an economic way considering that resources are scarce. Efficiency therefore implies doing the right things in a rightful manner. No third party is made worse off.Following
- Which clustering method is the most realistic and descriptive in ecological terms?
I know that both 'Single-linkage' and 'Complete-linkage' clustering are monotonic methods (non-metric), which is great under a theoretical point of view. Nevertheless, 'Group-average' clusters sometimes are easier to describe.
I'm working with Antarctic macrobenthic communities, and I would like to know which of these three methods is the most adequate for an environmental analysis based on your own experience.
Thanks & cheers!
nMDS in PRIMER or R package 'vegan'; PERMANOVA to establish significance of between-groups differences, CCA, PERMDISP or covariate PERMANOVA to examine environmental drivers of assemblage composition or difference; see Howell 'A benthic classification system to aid in the implementation of marine protected area networks in the deep/high seas of the NE Atlantic' Biological Conservation 05/2010 if you are identifying biocoenoses.Following
- Anyone familiar with NMR of Cobalt complexes?
If a cobalt complex (that is expected to be Co(II)) based on functionalized triazole ring didn't give any peaks in HNMR, what could be the reason behind this ?
Thanks in advance for your suggestions
As mentioned by others the spectrum will be very broad but it may be possible to get one. Some examples can be found in Dalton Trans, 2011, 40, 1313 which details the NMR of Co(II) complexes, [TpPh2Co(dtc)].Following
- How can I culture Helicoverpa armigera (Herbst) under laboratory conditions?
I want to make the culture of the Helicoverpa armigera (Fruit worm of Tomato, Tobacco, Cotton) but do not know how can I prepare the culture of it.
Dear Uzair Ahmad rearing Helicoverpa armigera is a little difficult job if you are just using natural diets as larvae eat voraciously. Better you can use any of the artificial diets as many researchers have recommended above. Carola Meierrose have given you detailed note about rearing and diet structure. I suggestion is use antibiotic (amp) and vitamins solution to the diet which will inhibit the bacterial growth and increase the number of healthy generation. As per the facilities and funds available, you can use any of the sophisticated trays for rearing present in market. In other case you may use improvised things for rearing such small injections bottles (after throughly washing and cleaning) for rearing a single larvae each bottle and somthing like inverted stool for rearing adults with diluted honey as food in a small container . I have attached photos for your idea.. in the last i have attached photo of vial for doing an bioassay test. All the best..Following
- How can I verify or validate my dynamic analysis in abaqus: motion of a robotic mechanism with flexible parts?
I've imported a solid model of a parallel robot in abaqus and defined all the constraints, contacts, trajectories in joints and etc. It is moving reasonably. It's end effector has a little deviation from prescribe path. But the stress in some parts during simulation goes very high which seems wrong. I'm using dynamic explicit with automatic increment size in step.
I can't construct such robot and test it now! So how can I verify my results? Is there any similar work? Are flexible multi body dynamics in abaqus have been verified up to now?Following
- Is there an established reason why some patients show evidence of dual pathway electrophysiology in the AV node, and others not?
Dual pathway electrophysiology in the AV node is found in 50-90% of patients with AVNRT, and around 10% without AVNRT (see link #1). Since it is the differences in refractory period between the fast and slow pathways which give rise to a discontinuous conduction curve, it is tempting to say that patients with a continuous AV conduction curve have no difference in refractoriness between the fast and slow pathways. However, it has also been suggested that a discontinuous AV conduction curve may be suggestive of longitudinal dissociation of the AV node i.e. a structural change. Is there a definitive answer as to whether it is differences in structure, electrophysiology, or both, which give rise to continuous and discontinuous AV conduction curves? Any references to recent articles would be appreciated.
After my knowledge there is no demonstrable cause for this. No histological difference was demonstrated until now. It seems that 25% of population demonstrate duality, however only in a small part reentrant tachycardia was demonstrated. Some speculation on embryological differences were made but not proven. In somewhat is the same problem asking why some people are prone to AFl and some not (depending on the insulation made by crista terminalis.Following
- Does Phenotypic plasticity play a more significant role in the evolution of novel traits and how does it compare across species?
Often it looks like phenotypic plasticity provides individuals a chance to survive in the wild. Individuals with plastic traits may be more successful than non-plastic ones? If so, is this a ubiquitous phenomenon and what costs does an individual with a plastic trait incur? Do plastic traits have an adaptive value? How does it compare across species?
Thanks to Reinhard for providing a superb list of references.
I don't want to take this thread off on a tangent, but one of the interesting issues to ponder about phenotypic plasticity is how learning -- in particular social learning & "culture" -- fit into concepts of phenotypic plasticity. This is an area for potentially productive discussions between evolutionary biologists and social/behavioral scientists. The unusual attributes of human culture provides some difficult challenges for models of phenotypic plasticity. Apologies for the self-referencing below; easiest way to provide sources in bibliographies.
Flinn, M.V. (2013). The evolutionary biology of culture. In K. Summers & B. Crespi, (Eds.) Foundations of Human Social Evolution, Pp. 94-103. Oxford: Oxford University Press.
Flinn, M.V., Ponzi, D., Nepomnaschy, P. & Noone, R. (2012). Ontogeny of stress reactivity: phenotypic flexibility, trade-offs, and pathology. Current Topics in Neurotoxicity 3, (Mal)adaptive aspects of developmental stress, Laviola, G. & Macrì, S. (Eds.), Pp. 154-172. Berlin: Springer.
Flinn, M.V., Nepomnaschy, P., Muehlenbein, M.P., & Ponzi, D. (2011). Evolutionary functions of early social modulation of hypothalamic-pituitary-adrenal axis development in humans. Neuroscience and Biobehavioral Reviews, 35(7), 1611-1629.
Flinn, M.V. (2006c). Cross-cultural universals and variations: The evolutionary paradox of informational novelty. Psychological Inquiry, 17(2), 118-123.
Flinn, M.V . (2004). Culture and developmental plasticity: Evolution of the social brain. In: Evolutionary perspectives on child development. K. MacDonald & R.L. Burgess (Eds.), chapter 3, pp. 73-98. Thousand Oaks, CA: Sage.
Flinn, M.V. (1997). Culture and the evolution ofsocial learning. Evolution and Human Behavior, 18(1), 23-67.Following
- Any suggestions on In vitro release calculation of SLN?
I am using dialysis bag diffusion technique for in vitro drug release of Solid Lipid Nanoparticle of my drug.My receptor compartment is 300 ml of 70% methanol.My question is when I will calculate percentage of drug release in different time interval, should I multiply my drug concentration with 300 ml every time?
To check the mass balance on either side of your dialysis bag, you need to multiple with the volume.Following
- How can I extract the features from Human x-ray image?
Am working in medical images. I need information to extract the features from human body x-ray image. I alrady extract the skeleton of the X-ray image.
First of all: define in clear language what features you are interested in and for what purpose? Anatomy? Function? Study for example how the algorithms were developed for virtual colonoscopy. In that case a whole range of feature extraction techniques had to be combined. Without a definite goal or purpose, no simple answer can be given. An alternative case-study which is also described extensively and demonstrates a number of feature extraction techniques at work is how myocardial perfusion scintigraphy and CT-angiography of the heart are combined, the 3D-datasetsare merged and how subsequently various features could be derived from such datasetsFollowing
- What is the vertical distribution of soil invertebrates?
I am interested in interactions among soil invertebrates and I would like to have some opinions whereas the localization of soil organisms in the different soil layers may constrain their interactions. Does anyone have some references about this?
Thank you very much!
Hi, thank you very much for your contribution. As I can see, not much has been done yet, particularly in relation to trophic interactions among species as constraint by vertical distribution. I think that combined methods of soil stratified sampling and stable isotope analyses will provide additional insights in the future.Following
- Does anyone have a plasmid for Otx5 ISH probe for zebrafish?
I'm performing an In situ Hybridization on zebrafish and would need a probe for zebrafish otx5, expressed in pineal and parapineal. Does anyone have it (or maybe something similar).
Thank you Thierry, I've sent him an email :) I already have probes but this one would perfectly co-localize with the structures I'm looking into :) So hopefully, I'll get it soon :)Following
- Is Chalmers' so-called "hard problem" in consciousness real?
In his 2014 book "Consciousness and the Brain: Deciphering How the Brain Codes Our Thoughts" Stanislas Dehaene wrote "Chalmers, a philosopher of the University of Arizona, is famous for introducing a distinction between the easy and the hard problems. The easy problem of consciousness, he argues, consists in explaining the many functions of the brain: how do we recognize a face, a word, or a landscape? How do we extract information form the senses and use it to guide our behavior? How do we generate sentences to describe what we feel?
“Although all these questions are associated with consciousness,” Chalmers argues, “they all concern the objective mechanisms of the cognitive system, and consequently, we have every reason to expect that continued work in cognitive psychology and neuroscience will answer them. By contrast the hard problem is the “question of how physical processes in the brain give rise to subjective experience … the way things feel for the subject. When we see for example, we experience visual sensations, such as that of vivid blue. Or think of the ineffable sound of a distant oboe, the agony of an intense pain, the sparkle of happiness or the meditative quality of a moment lost in thought … It is these phenomena that poses the real mystery of the mind”."
Stanislas Dehaene's opinion is "that Chalmers swapped the labels: it is the “easy” problem that is hard, while the “hard” problem just seems hard because it engages ill-defined intuitions. Once our intuition is educated by cognitive neuroscience and computer simulations, Chalmers’ “hard problem” will evaporate".
Personally, I agree with Stanislas Dehaene's opinion.
"My theoretical claim is that the retinoid system, with its 3D retinoid space, is competent to provide us lucky humans with this phenomenal/subjective world."
Could easily be short-sighted arrogant... ;)
In different ways and bits and pieces nature is full of example of communications and responding to various inputs... bacteria do it through their sensors and move about through a fantastic molecular motor like mechanism at the base of their flagella and conduct current through pili... (when I was taking courses in microbiology as a student, existence of pili was well known but function was uncertain and speculated to be related to interactions with other cells).Following
- Can the concentrated formic acid damage the TCD?
So I'm trying to figure out how I can analyse a mixture of formic acid (FA) gas, CO2, CO and H2 using a GC equipped with a TCD and FID connected in series. I'm assuming the FID will detect FA much better than the TCD, the rest of the gases of course will be detected by a TCD. Now my challenge is that I have been advised FA can destroy the TCD at higher concentrations and to analyse it I will have to turn off the TCD or completely bypass it, now I need this TCD to be on for the other gases. My question is how destructive is FA and has anyone analysed it in the TCD before? Do you have any suggestions on how I could analyse this mixture without damaging the TCD?
A lot will depend on the alloy's used in the TCD, if - by accident- condensation is formed you will have troubles. Also presence of other species - chlorinated stuff for instance- will enforce the corrosive effect of FA.
You could use a 'dean switch' to select between FID and TCD during the run: best of both worldsFollowing
- Why there are there two spectral bands in phthalocyanine?
Generally there occur two bands in phthalocyanines i.e. B band and Q band. Why are there two bands in phthalocyanines ?Following
- Can we extract parasitic capacitances of a layout without an LVS check?
I have a new device and I have drawn the layout for it. It doesn't have an associated schematic. Would it be possible to extract the parasitic caps for it?
Actually its a new device and it's yet to be modeled at the circuit level and thus I don't have a corresponding schematic to it.Following
- What is the difference bwteeen potassium sources used in internal solutions for whole cell patch clamp?
I am wondering if anyone could give me some clarification on the benefits of using various potassium sources in internal solutions for patch clamp. I am currently using KMeSO4, and have seen research that used KCl, or K-gluconate (or some combination of the two) as the potassium source. I understand that MeSO4 can be a better anion for recordings in neurons, but what about other types of cells?
Thank you all very much for you help!Following
- Does anyone have a method for isolating guard cells from plant leaves?
I wish to isolate guard cells from plant leaves, If anyone knows a good method or a reference for such a method it would be greatly appreciated. .
You can find a protocole in the paper
Nisita Obulareddy, Shweta Panchal, and Maeli Melotto(2013) Guard Cell Purification and RNA Isolation Suitablefor High-Throughput Transcriptional Analysis of Cell-Type Responses to Biotic Stresses / Molecular Plant-Microbe Interactions 26 (8), pp. 844–849.
Tamara Kruse, Gary Tallman, Eduardo Zeiger (1989) Isolation of Guard Cell Protoplasts from Mechanically Prepared Epidermis of Vicia faba Leaves Plant Physiol. 90(4), 1382-6.
I hope this helps.
- Does anybody have any experience using variables lags (I mean F(GDP, Export, Patent(-1)) testing cointegration with Johansen cointegration test?
Can we estimate a model like F(Gdp,Export, Patent(-1) this? I found some publication which are shortly saying it needs to be used for patent lags. But I can not find any publication to show whether I can use variable lag in Johansen Cointegration test.
Cointegration vectors are estimates of long-run relationships or equilibria. Such situations are solutions where all short-run dynamics, i.e., lagged responses, have worked themselves out. Therefore, one does not specify lags for some variables relative to other variables for estimating the cointegration vectors themselves as you wrote in your F function. But in the Johansen and other approaches, one almost always does specify a lag order for short-run dynamics, which is a lag order for first differences that will be included during estimation. Thus, some lagged patent effects will be accounted for in that way. Note also that any and all long-run relationships such as (GDP - b1*exports - b2*patents) are lagged in the model. So you have lagged patents in that sense as well in the dynamics. The elimination of non-zero values for (GDP - b1*exports - b2*patents) is the error correction process.Following
- What is the best way to patch clamp an oligodendrocyte progenitor?
I am attempting a whole cell patch clamp on cultured mouse oligodendrocyte progenitor cells, and am having difficulty breaking in to the cell after making the initial seal (which forms very rapidly). Can anyone offer some advice on how to achieve a stable whole cell configuration in these cells? Would a perforated patch be appropriate here?
Thank you all for you help! It is very much appreciated!
The internal solution I am currently using is (in mM) 135 KMeSO4, 10 HEPES, 2 MgATP, 0.1 MgGTP, 8 NaCl, 0.1 BAPTAK4.Following
- What kind of response is observed when the bulk is made to act like gate and there is NO GATE in MOS??
There are double gated FETs. I want to see how is the response when the voltage is given to bulk,source grounded and drain is applied a voltage without second gate.
In standard bulk FETs you don't have any oxide layer in between the bulk and the region (as opposite to the gate) where the channel should form so it's pretty hard to form a channel! Applying a voltage to the bulk will probably polarize the p-n Source/Bulk and Bulk/Drain junctions.Following
- Any suggestions on GCaMP expression in the hippocampus?
I am injecting a virus (AAV9.Syn.GCaMP6s.WPRE.SV40) to express GCaMP6s in the mouse hippocampus. I am using young animals (around P20), and as most of the atlases I know base their stereotaxic coordinates in P56 animals, I cannot use them, so I'm injecting with no coordinates.
So, the first question would be: is there any atlas for young animals that I can use to inject more precisely? I haven't been able to find any so far.
Even though I am using no coordinates, I'm not having problems to hit the hippocampus. However, I almost exclusively see expression in the DG. Is this something common? Discussing this with colleagues, we came to the conclusion that even though the virus infects non-diving cells, it might be more effective infecting dividing cells, and in that case that would explain why the granule cells are more effectively expressing the protein. Does this make sense to you?
My last question (sorry this is getting so long) is regarding two-photon microscopy. I am trying different wavelengths for imaging the GCaMP (I know 920 nm is the optimal, but this is part of my experiment) and I think the shapes of the cells look different when I image them at different wavelengths. I don't really understand why this could happen. Does any one know anything about this?
Needless to say, I will be really grateful for any opinion or information regarding any of the points. Thank you for taking the time for reading the post. I hope to be able to help you in the future.
Thank you very much for your useful comments. I will check the literature for the coordinates.
Regarding the power, I didn't mention this but I am using three different power levels. But I only see differences when I change the wavelengths, no matter the power of the laser.
Thank you very much for your help!!
- Plasma from frozen blood samples?
We have blood samples from patients stored at -80°C. I need to separate plasma from the blood (for ELISA) and need the blood cells for DNA Isolation. I have already tried centrifuging but due to RBC lysis, it cannot be separated. Is there any other way to get both- the plasma and cells for DNA isolation??
The more appropriate way for the future would be to spin down the patient blood sample and separate the plasma from the RBCs in separate tubes before the freezing process. I wonder if you add the glycerol or any cryo protective agent to the RBC to be frozen. If you do, then the frozen RBC needs to be washed before you could use it for your study. This way, it will prevent a severe degree of RBC hemolysis as you thaw the sample out.Following
- How would you validate an e-learning degree as an employer?
Would you hire a person if he would be self-taught by e-learning courses. How would you perceive his accreditation if he states that he has conducted the same research and had the same level of education but by utilizing e-learning instead of attending an official university. Would that be depending on the source of the e-learning? In that case could you name any e-learning suppliers that you feel are valid for stating that you have gained sufficient knowledge towards a certain field?
Believe me! E-learning is fast being the mode for educating oneself. It takes many forms of distance learning. However, e-learning is mainly used for self fulfillment studies at a higher level by majority. The main reason being that a lot of commitment will have pilled up on an individual i.e going to work to earn a living, family responsibility among others. Such factors cause someone to change the mode of education, to the more appropriate one in a flexible manner. E-learning is just equivalent to any other form. The eagerness of one to learn is very crucial in an organization. Some people learn through self sponsoring, and hence have to balance work and education, and most of such go for e-learning. Most PhD candidates choose e-learning as it is the most flexible mode at that time, when someone has a family and a work to partake...................................... Its all about the organization in question. How they view such studies. But for me all is well.Following
- What are the basic differences between FFT and DFT and DCT?
I am new in Signal Processing, specially on speech signal analysis. so need to know about the discrete fourier transform and discrete cosine transform easily.
DFT is the discrete general version, slow. FFT is a super-accelerated version of the DFT algorithm but it produces the same result. The DCT convolutes the signal with cosine wave only, while the DFT/FFT convolutes with the complete complex wave e^ix = cos x + i sin xFollowing
- To what extent does an HIV/AIDS service integrate into primary Health care?
due to accelerating roll-out of ARV , HIV/AIDS services are integrated into PHC in order to increase the access of ARV by people living with HIV. however there is ongoing shortage of material and human resource
Intergration of HIV care in primary health setting is achievable. In dveloping countries where nurses are the core health care providers at primary health facilities, capacity building is vital. This does not only speak to giveng them didactic training, but also providing mentorship. In that way, since they come in contact with more patients than a doctor would, they can then provide comprehensive, holistic care in a one stop model. Integration has proven to be much easier between TB and HIV and SRH and HIV. All HIV patients maust be screened for TB and all TB patients offered HIV test. Those identified to be positive should be prepared to start HAART since TB is an AIDS defining illness. they should also be screened for other condition communicable and non-communicable and treated accordingly. With SRH, as women and hopefully together with their spouses/partners access SRH services, they should also be offered HIV test and if found to be HIV positive, counselled and evaluated for other conditions and prepared to start HAART. I think really having learnt from these, any client who present at the health facility should go through the same process.
Task sharing has also made it much easier for trained non-professional cadres to be able to offer double rapid tests and this facilitates diagnosis and referal of patients to professional cadres for further evaluation to start HAART.Following
- Can anyone suggest where i get CIF file for (Na0.8K0.2)Bi0.5TiO3 ceramics
I searched the CIF file for the refinement of NKBT ceramics, but i cant find.Following
- If i have a mixture of enzymes and proteins, is it possible to characterize and quantify all proteins at the same time?
If i have a mixture of unknown proteins (extracellular, membrane bounded and intracellular enzymes; regulatory proteins...you may briefly call it as a metaproteome), is it possible to characterize and quantify all proteins at the very same time? Or may i pin point UP n DOWN regulation of some specific protein/enzyme??
What may be the possible and reputed methodology?
Are you talking about quantification or about qualifying proteins? Maliha's last comment refers to quantification but Masood comment is focused on protein identification.
All the techniques mentioned above are reaaly good to characterise proteins but they are not good if you try to quantify proteins. For protein quantification there are several colormietric methods: Lowry, Biuret, Bradford, etc.Following