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  • Dr A. Kumar added an answer in Low-Voltage:
    Can you suggest references on how to measure very low voltage signals in the order of nanovolts?

    I am going to assemble a FMR system but I'm having problem in detect the signal from sample as these are of very low amplitudes. Can you please suggest some ways to measure these low varying signals from the noisy environment? Can you suggest other ways than looking for amplifiers as these are very costly?

    Dr A. Kumar · Harcourt Butler Technological Institute

    Dear Vinay

    Apart from the requirement of measuring equipment, for the measurements of such a small signal you need electromagnetic shielding of the test specimen. For this purpose you have to mount your sample in metallic sample holder with a very high vacuum inside. Proper shielded cable connections have to be used from sample holder to the instrument. Feedthroughs used in the sample holder should be highly insulating. I hope you might be taking care of these points in your experimental set up. As far as the instrument is concerned, you can use Keithley nanovoltmeters or of some other reputed manufacturer.

  • Yahya Alghamdi added an answer in Writing:
    Does writing quality in a first language corellates with writing quality in a second language?

    I am just wondering if ESL learners who write well in their first language will be able to write in the same quality in a second language. Are there any relationships between the writing quality in both languages?

    Yahya Alghamdi · Cleveland State University

    Dear All,

    Thanks so much for sharing your experiences here. I do really appreciate it. And I am so sorry for not particiating with your comments due to my busyness life estyle recently.

    In my opinion, only those who had the opportunity to learn other languages had the ability to judge on whether or not being strong enough in their first language has added smoothness and easiness when learning a second language. And what I mean by being strong is that they should be all ready have the competency and fluency in all language aspects like: reading with criticism; writing formally, academically and fluentely. 

    Most learners who started learning a second language, English language as an example, still haven't acquired the competencies of their mother tongue. Due to that, they found learning a second languge is challenging for them. Once they have acquired  the second language, they found that they become stronger in their mother tongue. For example, lets talk about my first language (Arabic) it shares a great similarities and characteristics of English language, specifically, the written language. We have the same structure of writing paragraphs and essays; the use of punctuations are all the same; we do have a formal and informal, academic and non-academic, language. For this reason I do challenge that if a learner whose first language is Arabic, and really has acquired the formal Arabic language --in a way so he can write academic papers and know a great number of academic vocabulary, he will find learning English language easier. Compared to a learner who is still unaware of his first language aspects.

    All in all, if some one wants to learner a scond language easily and smoothly, he ,first, should be fully aware of his first language aspects, grammatical and rhetorical, and be able to speak and write fluently and academically; if they share similarities. Otherwise, the second language acquisition will help to fill missed gaps in his first language.

    These are my own opinion and might be right or wrong.

  • Can I explore the association between two continuous variables using simple regression?

    Is it fine to explore the association by applying simple linear regression as I could visualize the positive association on regression line using scatter-plot? Also, this analysis would help me to treat one variable as a predictor and another as an outcome variable, it would also help to demonstrate how much variance is explained in the latter by the former. I have rarely encountered this way of analyzing the relationship between two variables, most scholars employ correlation analysis.

    Paul R. Yarnold · Optimal Data Analysis LLC

    Bouncing betas refers to division by zero. For example, when r=1 the SSE is zero, and division by zero (when computing the F statistic from which p is derived) is a problem.

    Assume the opposite in the example: predict height (H) using leadership (L)

    F(1,6)=2.55, p<0.162; R-squared =0.298

    Raw data model: H-hat = 3.640 + 0.423*L

    Z-score data model: z(H-hat) = 0 + 0.546*z(L)

    Thus, as is obvious, in this example X and Y can be "exchanged without problem". I recommend that anyone with a question on this subject should repeat this exercise using the data set that I provided, and should also experiment with their own data, make plots, replicate the findings I report, and so forth.

    It is surprising to me that this isn't common knowledge. This is all easy to work out theoretically by hand, whether algebraically or geometrically. It is enlightening and in my opinion, it is fun. When I took elementary introductory statistics four decades ago, demonstrating these facts was a classroom exercise. In that class, for fun I used geometry with raw scores to deduce the line that bisected y|x and x|y. I learned later that this was the primary eigenvector of the unrotated principal components model. My work revealed that the eigenvalue of the primary eigenvector of a two-attribute principal components analysis solution is [1+ABS(r)]/2, and that the eigenvalue of the minor eigenvector is [1-ABS(r)]/2. I wanted to extend this to problems involving more attributes, but other projects absorbed my time. 

  • Nikolai I. Kobasko asked a question in Quenching:
    Can one successfully use CFD modeling to investigate transient boiling processes?

    In heat treating industry cooling curves analysis is widely used for controlling quenching processes. Special standard probes with one thermocouple at the core  are used to control intensity of cooling. Such analylisis cannot provide enough data for computer simulation of the quenching processes. Many investigators use CFD modeling trying to apply it to transient boiling processes taking place during quenching. Is there any success in this field?

  • Can anyone tell us what the best values for A and E in the Arrhenius integral are?

    When we review the literature we find many different values used, and none disclose where and how they got the A and E values they employ, or why the value they use is different from others. References appreciated.

    Yurii V Geletii · Emory University

    What does "Arrhenius integral" mean? 

    See "Arrhenius plot in": 


  • What is your view about Duplicate Publications?
    Duplicate publication refers to publishing the same intellectual material more than once, and unfortunately, this issue is increasing rapidly these days. Do you consider it a form of plagiarism or academic dishonesty or serious academic misbehavior or something else? What is your suggestion for university and research institution leaders on how to deal with "academician" or "researcher" practicing such thing?
    Selvaraju Sivamani · Kumaraguru College of Technology

    Duplication publication must be avoided in research. If they are in different languages, then it is also considered as duplicate publication.

  • James Wilson added an answer in QRS:
    What QRS duration should be considered abnormal?

    A recent recommendation indicates that the QRS complex on routine ECG should be considered abnormal is its duration is of 120ms or more. I saw a young women of 150cm height and 45kg weight with the QRS duration of 110ms and a men of 195cm height and 100kg weight with the QRS duration of 120ms. Actually, who of them had abnormal QRS duration?

    James Wilson · Texas Heart Institute

    based upon histrorical criteria, any QRS duration greater than 100 ms is a conduction delay and must be defined according to the conduction system involved or as a nonspecific conduction delay. The interpretation of the ECG is separated from the criteria for improvement with pacing. In the interpretation of the ECG, if the QRS duration is abnormal, you must state that. It is the treating physicians decision as to whether additional therapy will be of value.

  • Selvaraju Sivamani added an answer in Ethanol:
    Which is the correct HPLC column to measure ethanol?

    To measure ethanol from yeast fermentation.

    Selvaraju Sivamani · Kumaraguru College of Technology

    What brand HPLC you are having?

  • Rahul Krishna added an answer in Nitric Acid:
    Ho can I remove Al and Cu oxide layers using HNO3 or NaOH?

    I will be etching Al6063 and Cu101 to remove the oxide layer. I will use nitric acid HNO3 or NaOH solution. Is either solution better for a bath containing Al and Cu plates?

    Is Al oxide and Cu oxide soluble in these solutions? Does the oxide layer dissolve, or does the solution only break the bond, still leaving oxide particles suspended in the solution?

    If the Al and Cu plates are allowed to dry with the solution on the surface, and then exposed to a vacuum, would the dried solution continue to etch the surface in the vacuum or is the etching action halted while in a vacuum?

    Thanks for your help!

    Rahul Krishna · University of Aveiro


    First, please tell me yours Al and Cu plates are in same bath solution or separate one. If individually you want to remove oxide from foth metal species there is different protocol for both of them. For Al surface etching ..use HCl with some CuCl2. By this reaction Al will oxidize and Cu will reduce and makes fine particles on surface of Al which you can remove by simple washing. ((((Take care this is highly exothermic  reaction initially in very less amount you should use, better do the one experiment with small piece of Al foil and above reagent (CuCl2 + HCl mix.). By this reaction you will clearly see dissolution of Al metal/foil and formation of Cu particles along with effervescent of H2, temperature increment. Should  do in big open mouth beaker...in fume hood and with careful manner.

    Regarding of Cu try to use Conc. FeCl3 solution. Probably, it will work. This reaction is quite simple no need to very disturb but this will long time around 2 days.

    The use of HNO3 is not a good idea to cleaning of Cu surface because it makes very toxic NO2 gas and really, it is very nervous system. In my experience the minute amount is danger. Any way, please try with FeCl3 if its not work please let me know I will try to say more good options. Best of luck :))))

  • Halil Aslan added an answer in Special Education:
    How to assess effectiveness of counseling services in special education school or center in the turkey?

    As we know that increasing number of school counselors are working in the special education center. we face with many unique obstacles. How to assess effectiveness of counseling services that we provide to studentS with mentally retarded students. 

    Halil Aslan · Middle East Technical University

    thank you very much for your valuable comments, however I took course related to research methodology in this semester. I clearly understood what I would do before conducting this type of research questions.

  • Selvaraju Sivamani added an answer in Universities:
    If you are a university leader, what you will do to promote your university?
    There are many challenges issues faces university leaders to promote their university. These challenges are local, regional and international
    Selvaraju Sivamani · Kumaraguru College of Technology

    Collaborative research outside country

    Best infrastructure

    Best academic heads

    Research publications in refereed journals

    Outreach and extension

    Good administration

    Establishment of research centres

  • What are the factors which facilitate transfer of learning?

    What are the factors which facilitate transfer of learning?

    Larysa V. Lysenko · Concordia University Montreal


    There are a few models that are not limited to adult learning though. For instance, you may like to look into cognitive flexibility theory by Rand Spiro from Michigan State. It is a constructivist view mainly concerned with transfer of knowledge and skills beyond their initial learning situation and pertains to learning in complex and ill structured domains. A "canonical" paper (at least for educational technology people) by Perkins and Salomon on transfer of learning can provide you with an overview of transfer, its mechanisms and conditions. Here is a link https://learnweb.harvard.edu/alps/thinking/docs/traencyn.htm

    My best,


  • Selvaraju Sivamani added an answer in FP7:
    Is there anyone working on producing bio-fuel from algae to join to us in a proposal FP7, 2014?

    Dear colleagues,

    We looking for a partner work on producing bio-fuel from algae. We cultivate algae and need an expert on bio-fuel from Algae.

    Selvaraju Sivamani · Kumaraguru College of Technology

    Which bio-fuel you want to work on, bioethanol or biodiesel?

  • Sajith Dananjaya added an answer in Chitosan:
    Why are chitosan nanoparticles insoluble in acetic acid?

    I prepared chitosan nano particle using following step
    Low Molecular weight Chitosan (Sigma) was dissolved at a concentration of 3 mg/ml in 0.5% acetic acid solution, then raised to pH 4.6 with 10 N NaOH and filtered the solusion using 0.45 filters.
    A solution of TPP at the concentration of 1.0 mg/ml was prepared with deionized water and filtered the solusion using 0.45 filters Then, 10ml of TPP solution was added drop wise under constant stirring to 25 ml of the chitosan solution.
    After that opalescent suspension were separated by centrifugation at 16,000 rpm for a period of 30min at 14 °C.
    The supernatant was discarded and the wet pellet of CS/TPP nanoparticles was collected.
    The pellet was washed with deionized water and freeze drying, and stored at 4 °C for further studies

    Sajith Dananjaya · Chonnam National University

    Dear Shahsavari

    Thank you very much for your answer. I will  follow above steps 

  • Does anyone analyze body construction and (un-)visibility in protest movements?

    I would like to connect with anyone interested into negotiations about the body and body constructions from a gender perspective in protest movements. What interests me most is how to research negotiation processes of (un-)visibility.

    Terrill Nickerson · Walden University

    I do not know if this is helpful, but here goes.  On the evening that the Ferguson indictment announcement was released in Ferguson, MO, CNN was providing a live stream of the crowd and ensuing events.  The helicopter live stream was silent with no editorial comments.  It was just raw footage of the crowd from above.  I watched for four hours, and it turned out to be a tremendous example of complex systems theory (chaos theory).  You might be able to contact CNN ask acquire the footage.  it has a good view of the crowd participants and body un(visibility) estimates might be possible.  I hope this helps.


  • Anna Git added an answer in Western Blot:
    Why do my western blot bands are coming out like this ?

    The extreme right lane is the marker.... rest all samples.... all sample bands are coming in m- shapes.... need expert comments and help in troubleshooting.

    Anna Git · University of Cambridge

    My guess is sample preparation or gel overloading. You do not specify the tissue or lysis buffer. Is the sample fatty/sugary? Is the prep very concentrated? Is there enough SDS in the buffer?

    Also, you can try slowing down the electrophoresis (drop the amperage), it sometimes suffices to straighten ugly bands!

  • Rozita Nasiri asked a question in FTIR Analysis:
    Which type of functional group will appear in FTIR analysis as peaks after covalent conjugation of enzyme?

    The ―COOH of nanoparticles was activated using EDC/NHS and then covalently attached to the ―NH2 of the enzyme, forming ―CO―NH―. Now, which peaks number will show that the conjugation successfully done? 

  • Selvaraju Sivamani added an answer in Lactic Acid:
    How can I estimate volumetrically malic acid and lactic acid?

    Is there any titration method  for estimation of malic acid that may check the malolactic fermentation?

    Selvaraju Sivamani · Kumaraguru College of Technology

    Titrimetry is used to estimate malic and lactic acids volumetrically.

  • Rahul Krishna added an answer in Mesh:
    What is the logic behind carrying out disintegration test through 10 mm mesh and uniformity of dispersion through 22 mm mesh?

    any specific reason/ logic? Physiological relation ?? plese, help me out

    Rahul Krishna · University of Aveiro


    This is very simple. First, the mesh size define the number of opening in per inch of screen. So in case of low number as 10... big particles easily shorten refer as disintegration. When mesh size is increase such as 22 the opening is small and only fine sieving can occur that can  refer as dispersion.

  • Anna Git added an answer in microRNA:
    What is the range of miRNA concentration in blood or serum?

    There are several methods to study miRNAs from blood samples and most commnly PCR. To compare the concentration we use deltaCt as their unit to compare references. But I am wondering what is the expected range of miRNA concentration in Molars in the blood. Is there any comperative study?

    Anna Git · University of Cambridge

    I am not convinced that a proper answer exists. Firstly, there is too little miRNA to be quantified directly. For example, in 10 micrograms of brain total RNA (very little RNase activity, so no smear), I can visualise 1-2 nanograms of miRNAs using SYBR Gold staining. In blood, the quantities are even lower, the RNA is degraded and the miRNAs may be found in exosomes or similar structure, rendering a molar expression inaccurate.

    To do a direct quantification, one should use dilution curves of synthetic RNA in conjunction with RT-qPCR. Delta Ct by itself assumes perfect priming, perfect logarithmic amplification etc, and does not satisfy the miQE standards that should be met for reliability and publication. Moreover, while qPCR is usually fairly robust, RT is far from it. Try it yourself - input half and double the amount of RNA into your RT reaction and see if you get 1 Ct difference at the end!

    I wish I could be more helpful!

  • duc an ho asked a question in Abaqus:
    Uniaxial tensile and compressive tests for hardened cement paste?

    I'm using the damaged plasticity concrete law implemented in Abaqus to model the behavior of the hardened cement paste (with a ratio water/cement between 0.35 and 0.5) in the application of grouted rockbolt. It's necessary to identify the hardening/softening rules for the plastic behavior of the hardened cement paste, which can be determined from the unixial tensile and compressive tests. Could you please give some references, where I can find the stress-strain curves of these tests. Thank you very much.

  • James Wilson added an answer in PCI:
    Is new left bundle branch block no longer a class 1 indication for emergent reperfusion?
    ST elevation and new/presumed new LBBB were the indications for emergent reperfusion (in the thrombolysis era). Is LBBB no longer an indication in the PCI era? Could anyone point me to evidence for or against?
    James Wilson · Texas Heart Institute

    as we and others have published, LBBB is not a surrogate for STEMI outside of clinical indications and should not be a solo indication for a trip to the cath lab

  • Imre Tóth added an answer in Organic Synthesis:
    Why it is necessary to used deuterated solvents for NMR experiments?




    Imre Tóth · University of Pannonia, Veszprém

    Everybody gave correct answers except Somnath!

  • Rahul Krishna added an answer in Reducing Agents:
    Do palladium nanoparticles can be synthesized by dissolving PdCl2 in NH4OH aqueous solution without reducing agents ?

    I have read an article which the palladium(ll) solution is reduced without reducing reagent in  ammonia solution , whether is it true? Do
    Palladium(ll) oxide formed in the ammonia solution ?

    Rahul Krishna · University of Aveiro


    Try to use microwave synthesis under inert atmosphere. It will decompose Pd complex and probably, you will get Pd NPs. However, I am not sure by this method some oxide formation because the extra hydroxide ions definitely dominant the reduction process. Moreover, can you say about how you dissolve PdCl2 in water because this salt solubility at pH 7 is negligible also in basic condition.  

  • Shaina Alysa Kelly added an answer in PECVD:
    What is a good RIE etching formula for generating smooth structures in SiO2?

    I am etching quartz substrates with a March Plasma RIE machine (but also have access to a PECVD Oxford PlasmaLab80 if necessary) and would like to produce 60-100nm deep trenches in the areas not covered by a copper mask. I also would like these trenches to be as smooth as possible with minimized sidewall tapering.  

    I know there are many RIE formulas out there, but was wondering if anyone had some they knew worked particularly well for these machines and the desired output? Thank you in advance!

    Shaina Alysa Kelly · University of Texas at Austin

    Thank you for the suggestion. I will try the etching process with the PECVD!

    ~ Shaina

  • Can we obtain the number of generators of a free group without Reidemeister-Schreier Index Formula?

    If so, how?

    This is particularly crucial for getting the torsion-free normal complements of units in group rings in case of non-abelian groups.

    James F Peters · University of Manitoba

    This is a good question.

    In addition to the incisive answer given by @Collin Bleak, consider

    J. Mangahas, Uniform exponential growth of subgroups of the mapping class  group:


    See Theorem 1.1 p. 2, for the generation of a rank two free group.

  • James Wilson added an answer in Cardiology:
    Why does a heart attack hurt? How is the pain mediated?
    As the myokardium itself is not or hardly innervated by afferent nerves, I wonder how the pain in a heart attack is generated? Is it mediated by visceral innervation of the coronary vessels or by afferent nerves of the perikard?
    James Wilson · Texas Heart Institute

    A simple version is that the heart is hooked to the brain through nerve pathways that developed when we survived the dinosaurs. Their primitive and don't localize very well. That's why people with heart attacks often say, it wasn't pain or, it wasn't in my chest. The nerve pathways hooked to the brain just tell you that something is badly wrong. They just don't always tell you where. that's why every ER doc everywhere will ask for an ECG for any adult who looks sick. The above description is nice and correct but the short version is protopathic pain, c fibers and thalamic transmission.

  • Adolfo Alarcon Campos asked a question in Intonation:
    Is it convenient to record with a wireless microphone in intonation descriptive works?

    Hi everybody. I'm working in intonation and I'd like to know what you think about recording with a wireless recorder. Do you think that I could lose valuable information on my recordings? Should I take account anything about wireless signals? I'm using a TASCAM DR-40 recorder and my micro is a electric condenser micro Shure pg30 and its frequency response is 60 Hz to 20,000 Hz and it's cardiod (Output impedance 1200 Ω@ 1Khz) and I also use a wireless microphone system Shure SVX (details in the attached image). On the other hand, are there papers about suitable microphones (or suitable microphone systems) that I should use in intonation (or in phonetics, at least). Could anybody help me? Thanks for any information.

  • Ella Pavlotskaya added an answer in Phonology:
    Are minimal pairs and auditory discrimination grouped within phonological awareness?

    I want to know if I can group minimal pairs and auditory discrimination in phonological awareness category or these three are totally different?

    Ella Pavlotskaya · Florida Hospital, Tampa

    My understanding of phonological awareness is the ability to correctly link phonemes to graphemes, as in reading acquisition. A child is aware, for example, that the letter x signifies the sound combination /ks/.  This is why words like "xylophone" to illustrate the concept are confusing, and some modern dyslexia remediating methodologies use words like "fox" instead.   Minimal pairs are sounds that are different from each other in voicing, whereas the same in placement (e.g., /b/ and /p/ are both bilabial sounds, but one of them is produced with vocal fold vibration and the other is a silent burst of air; similarly, /g/ and /k/ are both velar sounds, but one is voiced and the other is voiceless).  Auditory discrimination is a very early on process.  I believe babies acquire this skill by 6 months of age.  If your question is whether phonological awareness may be used as an "umbrella term" for both auditory discrimination and minimal pairs, I would say probably not.  To my understanding, phonological awareness is a metalinguistic skill, learned much later in development, than auditory discrimination, which is a developmental process. However, when there is a breakdown, and a child lacks the auditory discrimination skills and is unable to hear (and/or produce) sounds correctly, he/she requires remediation, where awareness of the difference between the sounds is explicitly taught via minimal pairs, often before the child is even able to read.  I hope this was helpful.

  • Rahul Krishna added an answer in TiO2 Nanotubes:
    Mechanical property of anodic TiO2 nanotube?

    Please tell me about the mechanical property of anodic tio2 nanotubes, are they fragile, if they are how can I make them rigid?

    Rahul Krishna · University of Aveiro


    Yes, anodic TiO2 nanotubes are very fragile. Take care at the time of handling. I have some experience it is very tough job to handle it. However, i have used  scotch tape to provide the support on back side for electrical resistivity measurement. However, this also have some problem after the measurement to get rid of tape and contamination. Any way, best of luck,,, and if I will have any other idea surely i will tell.