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  • Michael Fitzgerald added an answer in Carbonates:
    The role of BaCl and pH range 8.3 to 3.7 in estimating soil microbial respiration using SIR method.

    Hi All,

    Can some one confirm (in basic terms):

    1.The reasoning behind the addition of BaCl2.

    2.Why its more desirable to record the HCL titrated btw pH 8.3 & 3.7

    My understanding is:

    -Bacl2 precipitates Carbonate  therefore enabling the amount of NAOH consumed during the adsorption of CO2 to be determined 

    -After the addition of Bacl carbonate is locked away and Biocarbonate is more prevalent bwt ph 8.3&3.7 

    Any help would be much appreciated

    Michael Fitzgerald · Elizabeth Macarthur Agricultural Institute

    Some more detail on the question above:

    I am trying to estimate soil microbial using substrate induced respiration. I am using Naoh to absorb carbon dioxide and back titrating with HCL.

  • Do we need to conduct Exploratory Factor Analysis when we are using all standard questionnaires in our study?

    I want to understand the implications of exploratory factor analysis, whether we need to conduct it on standard questionnaires

    Razia Shaukat · COMSATS Institute of Information Technology

    Thanks Mr. Peer van der Helm for your valuable feedback.  This is indeed a great piece of advice.

    Thanks again

  • What do you think about the green building-certification in developed countries?

    A cheaper house price will save you money at the time of your purchase, and a high energy-efficiency rating (EER) will save you cash on each month’s energy bill. One problem is that there are far too many factors in each property to produce a single rating.
    According to the global Energy Efficiency Indicator survey 3 years ago, 44% of the respondents said they wanted a green building-certification, but the process was hindered by the lack of a common EER.

    What do you think about it? Any contribution is greatly appreciated.

  • Yuan-Yeu Yau added an answer in Primer:
    What percent of template can be synthesized during PCR?

    For example, the parameters for PCR are denaturing at 95, annealing at 58 and elongation at 72, while the melting temperatures of primers are around 60.

    Yuan-Yeu Yau · Northeastern State University

    That is an interesting question. I don't exactly know the percentage, but I think if you add tons of DNA template, but an extreme low primers' amount, then I think this will cause a low percentage of templates got amplified (synthesized). For example, you have 10000 copies of templates, and 10 copies of primers. The percentage can be determinate by the amounts of templates and primers you add. DNA polymerase used might also play a role.

  • Thibault G Sana added an answer in Colony PCR:
    Can anybody give some suggestions for knocking out essential genes in Pseudomonas aeruginosa?

    I need to construct a conditional mutant for an essential gene in PA14. At first, I knocked in a copy under pBAD promoter into chromosome via attB site using integration plasmid. Gene expression was confirmed by WB. So, I go ahead to transfer knock-out plasmid by electroporation. This plasmid contains upstream, Gm cassette, and downstream homologous arms. I can get single crossover mutant, which is confirmed by colony PCR with upstream screening primer and Gm internal primer. This PCR product was confirmed by sequencing. This strain was GmrCBCr.

    I am very happy to continue to use 10% sucrose+0.2% arabinose to screen double crossover mutant. I got many GmrCBCs colonies. Unfortunately, the gene seemed to restore to wild type. Colony PCR using screening primers showed the same size as wild type, which should be 500 bp shorter. 

    I am confused. How can a single crossover go back to wild type, but still with Gm resistance? I repeated several times. The same thing happened. what should I do? can anybody give me some suggestions? I appreciate your nice help.

    Thibault G Sana · Stanford University

    Congratulations! Happy to see that I could help.

  • What thickness should Ti Adhesion layer be?

    Making 100 nm wide nanowires to break controllably using electromigration, see DR Strachan et al. for example.

    Previously I've used 2 nm Ti adhesion layer and 14 nm Au; I use ebeam evaporation to deposit the metals in vacuum, into a PMMA negative from EBL. I am concerned however that a 2 nm film of Ti is not continuous, and that 4 nm would be safer.

    I am wary of going too thick however, as when the gap breaks via electromigration, I try to trap a molecule in the gap, connecting two Au electrodes. the Ti can be problematic for two reasons:

    1. If the exposed Ti, which is presumably not oxidized because it was protected by the Au, does not also electromigrate then it will short the ends. Some recent work suggests that Ti can electromigrate however so it is possible that it would do so.
    2. If the Ti does electromigrate, a Ti-Ti tunnel junction would not likely contain the molecule (I use thiolated molecules to form self-assembled monolayers on the Au).

    Previous work, my favorite of which is from Takhee Lee et al. has used 1-2 nm of Ti or Cr, so I am further hesitant to go thicker. It is difficult to test this matter as well.

    Thanks in advance for any advice.

    Darin Bellisario · Massachusetts Institute of Technology

    Whoops of course, SiO2; sorry for the omission.

  • Danielle A. Allessio asked a question in Scoring:
    How do I calculate the Pearson correlation coefficients between individual item scores and total score with SPSS?

    Do I perform a bivariate correlation between the mean of each likert scale variable and the total score mean?  

  • Robert Shuler added an answer in Special Relativity:
    Is relative simultaneity a misinterpretation of Special Relativity?

    I really need a lot of feedback on this particular issue.

    I think that relative simultaneity is a computational effect of no consequences to real temporal relations. This is based on my analysis of simultaneous trajectories.

    My claim of apparent nature of relative simultaneity is based on the assertion that relative lengths of rigid objects or points moving at a constant relative distance to each other in a stationary system are not conserved (in general ) in the moving system after Lorentz transformation when expressing multiple points trajectories in terms of common time of the moving system.

    More details in the linked document and relevant draft article available from my RG profile

    Robert Shuler · NASA

    Valentin, probably you should ask a specific question and start your own thread.  There are many on here who will answer.  I have other things on my mind right now, and after looking at your posts, I think it would take a bit of time.  These questions tend to recur on RG over and over, with new people asking them.  I just think if my approach didn't register with you, then maybe let someone else try.

  • Amar Agarwal added an answer in Trace Analysis:
    How can I conduct the trace analysis?

    I would like to know how can we conduct the trace analysis when we focus on the crystallographic characteristics in TEM or EBSD.

    Amar Agarwal · Indian Institute of Technology Roorkee

    Dear Dr. Nolze,

    Thank you very much for the information. I have given your answer an 'up'.

  • Satwinder Singh added an answer in Glass Ceramics:
    Why the Raman peaks in glasses show decrease in intensity or cease to zero with increase in modifier cations?

    Glass ceramics generally have well defined Raman peaks in Raman spectrum. However with the increase in modifier content, I observed that intensity of the peaks decreased and ceased to even zero with further modifier content increase. Is is related to the exploitation of center of symmetry of glass network, or some other phenomenon is contributing to it???

    Satwinder Singh · Thapar University

    I am thankful to you Dr. Roughani for that much informative discussion. I have got the base to that concept, and now I can go for the literature to strengthen it.

  • Aulia Sukma Hutama asked a question in VASP:
    Too long planewave cutoff?

    I am running calculations in vasp. I have checked the planewave cutoff convergence to 400 eV. However, I also use 550 eV to make sure that it is "safe". In geometry optimization, the one that has 550 eV has lattice parameter longer than experiment by 0.1 Angstrom and the one that has 440 eV has better agreement (0.005 A longer than experiment). How does planewave cutoff energy affect the geometry optimization? 

  • Li-Ming Lee added an answer in Nitrocellulose:
    I would like to know what is prefer BSA or nonfat dry milk in western blot?

    I would like to know which is prefer BSA or nonfat dry milk to block nitrocellulose membrane.

    Li-Ming Lee · TaiGen Biotechnology Co., Ltd.

    Hello there! Personally, I think both of the choice are fine. I used both 5% non-fat milk and 3 % BSA in TBST for blocking for 1 hr before, and there are no significant differentce I think. But BSA is much expensive, so I guess it depends on your situation. Good Luck!

  • Bikramaditya Ghosh added an answer in Raw Materials:
    How to construct price index of raw material for cross section data?

    i have different items in raw material. i need price of raw material for my translog cost function. please guide me.

    Bikramaditya Ghosh · International School of Management Excellence- ISME

    In fact it is more suitable in a cross section scenario. I am attaching an excel here with  a panel data set (dummy), for 3 projects, each with 7 year completion, 3 RM (Raw Material). You can use stata for the Panel data to get an accurate estimation of Price.

  • Ganeshprasad Arunkumar added an answer in Alleles:
    Can anyone explain me about the direct counting method of allele frequencies?

    I am working with some analyses to identify the association of gene alleles with a disease. I found some difficulties in understanding the direct counting method of allele frequencies. What is the principle? How do we do the method? What are the advantages and disadvantages?

    Hope you can help. Thank you 

    Ganeshprasad Arunkumar · SASTRA University

    Gene counting method, as the name implies, is just counting the number of copies of the gene present in an individual and hence a population/study group. In a diploid organism, like humans, the gene counting is done by first assigning the genotype to every sample. All the gene count in a homozygote is 2 while in a heterozygote is 1 for each gene. So if you have two alleles A and B, then gene count for:

    the homozygote AA is 2A and

    BB is 2B and

    heterozygote AB is 1A+1B. 

    If a population/group of 100 individuals (total chromosomes/gene copies = 100x2=200, diploid genome) have 70AA, 10AB and 20BB then the gene count is:

    Count of A = 2x70+10 = 150

    Count of B  = 2x20+10 = 50

    This is an easy way to see if there are any differences in the frequencies of the alleles between groups. In the above example the group had an excess of A compared to B.

  • Sajjad Jannesar Malakooti added an answer in Copper:
    In which conditions that must AM2A oxide collector reagent be maintained to have high recovery?

    This is used in Copper flotation. I am performing lab tests but there are just a lot of unknown factors like what pH should I use or how much conditioning time I need.

    Sajjad Jannesar Malakooti · Islamic Azad University

    Dear Risa Mar Santes


    The important parameteres in copper flotation are (collector type and dosage, pH modifiers and adjusted pH, dispersing and depressing agents, conditioning and frothing times and so on. please pre-study such as mineralogical and characterisation studies, then you find effective parameters and up and down level in parameter.

    Finally, you can use the experimental design with DX7 software and optimised the tests.


  • What is the definition of people-centered of ASEAN or EU or any region? Is there any official definition?

    Regionalism, Politics, International Relations, Human Rights, Human Security, Governance

    Sharifah Syahirah SS · Kolej Poly-Tech Mara

    Hi Paul, Thank you so much for your feedback. From my point of view (human rights perspective), there is an urgent need to define and have an official definition of people-centered of ASEAN.

  • Can anyone suggest how to measure employee engagement?

    employee engagement with regards to gen Y work performance

    Sharifah Syahirah SS · Kolej Poly-Tech Mara

    Salam Prof,

    From my point of view, employee engagement can be measure in  terms of reciprocity, platform to engage, eagerness to achieve company's objectives and empowerment level. However, when we are discussing about Gen Y (a product of developing towards developed country), there's an urgent need for us to learn and implement best practices of advanced countries policies and rules (in our own mold). Some of our work policies not compatible with Gen Y because this generation why of thinking and expectation are different than the previous Gen.

  • Tarkes Dora added an answer in Elastic Modulus:
    How do I assign viscoelastic material properties into Abaqus?

    i am simulating the behavior of tissue on Abaqus

    i want to assign those material properties please:

    time-dependent viscoelastic properties were assigned to the cytoplasm using this model (E0 = 6.5 kPa, E∞ = 4.3 kPa, ν = 0.5, τ = 15.4 s), where E0 is the instantaneous elastic modulus, E∞ is the equilibrium elastic modulus, ν is poisson’s ratio, and τ is the characteristic relaxation time.

    anyone can help

    thanks in advance

  • Is there ana nti-Lubricin antibody with cross reactivity to human or human plus rat?

    Pl provide me cat log number of working anti-body for localizing LUBRICIN (PRG-4) in HUMAN TISSUE  or in Human and Rat tissues both  for Immunohistochemistry.

    Many thanks,

    Subhash C. Juneja · Toronto Western Hospital

    Thanks, Magali, I e-mailed to him,

    Best, Subhash

  • Daniel Davis added an answer in Wittgenstein:
    Is is possible to view space as a substance, on a par with material substances, distinct in its nature but also possessing causal efficacy?

    Following Kant Hume, Wittgenstein and most Western philosophers, the majority view is that this effort would be foolish metaphysical speculation, flights of fancy that we might want to pursue but should not.

    I argue that their epistemology-based approach leads Western culture to overlook the space between things, as it focuses on the details of the observables and ignores the ubiquitous, non-material substance with which all particular things must coincide. 

    Daniel Davis · Strayer University


    Thanks for your reply. I'll put you down in the NO column.

    I fear  you do miss the point, however, that space might be quite observable, just not particulate. Kant would deny space is a substance, since he views it as a category of the mind. Hume certainly denies it's substantial nature (and that of matter, too) and, to Wittgenstein, a spatial substance would be one of those things whereof we cannot speak, so we should be silent about it.


  • Alok Nahata added an answer in Soxhlet Extraction:
    What happens to the mass of extract and yield of extract for varying raw material mass and solvent quantity?

    Material : LEAF material 

    Mass: 2g, 3g, 4g

    Solvent (ethanol): 250 ml, 275ml, 300ml 

    Temp. :75 deg C

    Soxhlet extraction time : 3 hrs

    Alok Nahata · Dr. Harisingh Gour University

    Dear Ananth

    If you keep the solvent volume constant, then also the yield would increase as every time you are getting the same solvent coming in contact of the drug again and again. Normally in a 500 ml soxhlet apparatus, we keep a solvent volume around 300-350 ml. Solvent should be sufficient to extract the drug for it is evaporating and condensing, not the extract. 

    If you are changing the amount of solvent, I don't think it is going to have a significant impact unless it is very less in quantity which makes extraction difficult. Effect would be with the quantity of the drug as the more the drug comes in contact with the solvent, the more it penetrates the leaf tissues and more is the extraction. So it is the surface area that matters and not the solvent. Packing of the drug should be uniform and optimum, just sufficient for the solvent to easily pass through the drug. If you pack too heavily, then also extraction would get affected as the cycle might run without efficient extraction. Time is an important factor which you have kept constant. So in your case, drug load would be more important. You will see a higher yield with the 4g drug sample.


  • Dachuri Vinay asked a question in Yellow:
    Estimation of bacterial pigment concentration?


    can any one tell me the method, how to measure the pigment concentration. my pigments are yellow and orange pigments from symbiotic bacteria. 

    thank you.

  • How can I evaluate the cytotoxic text result with structure-activity relationship (SAR)?

    How can I evaluate the cytotoxic text result with structure-activity relationship (SAR) ? but not the QSAR. Does anyone have the link or procedure for this analysis?


    Siow-Ping Tan · Universiti Pendidikan Sultan Idris (UPSI)

    Thank you for your kind help. I got the problem solved. :)

  • Edson Araújo asked a question in Soil:
    Does anyone have a chapter book named Relations Between Iron Oxides, Soil Color, and Soil Formation by U. Schwertmann?

    Is achapter from the book soil color

  • How to conduct validation and reliability test for interview questions which is in more easier and fast way?

    I have a plan to conduct validation and reliability test for my interview questions regarding the governance in SWM, but i still searching for the best method. I hope anyone can help me. Thanks. 

  • Abhijit Mitra added an answer in Crabs:
    Can anyone identify this crab ?

    Please help us by identifying this freshwater crab attached with proper scientific name 

    Abhijit Mitra · University of Calcutta

    State the place of collection

  • Jamie Farren added an answer in Tephra:
    What could have caused colouration of dairy industry effluents after it has gone through allophanic soil filters?

    Tephra subsoil (allophanic) columns are used to determine the soils phosphorus (P) sorption capacity to remove P from dairy industry wastewater (pH = 8). The effluents collected had shown colouration in which the influent was colourless where the effluents were pale yellow to intense yellow. Could it be due to the presence of iron? If so how do I quantify iron in aqueous solution? Thanks!  

    Jamie Farren · West Texas A&M University

     Although you are correct that Iron can cause an effluent stream to turn yellow...a lot of other things can do that as well. Given that your are using allophanic filters, it doesn't seem likely that the cause of your issue here is the presence of iron. 

       Tannin is one thing that could be producing this effect, but accumulation of Tannin will lower the pH of your wastewater. While it is true that an allophanic filter should reduce this sort of issue, it isn't quite as effective at that than for stopping say, heavy metals like iron. In my experience, the sort of filter you are using would deal with a maximum of about 80% of Tannin-lignin attempting to move through it.

    If you haven't already, I would check the pH of your discolored effluent and compare it with the influent and effluent that is not yellow. If the pH of the discolored effluent stream is much lower than 8, you should probably consider applying a chemical test for tannin or, more generally, phenolics.

      With all that said, I will mention one more thing about the possibility of iron: if you do not currently have a system in place to add air or some other oxidizing agent to your waste stream (pre-filter), then any iron in the stream won't have enough time to become insoluble (Fe3+).   If that is the case, then your filter won't matter much. 

  • Alok Nahata added an answer in Ferula:
    How can you deal with Ferula Asafoetida?

    Can anyone provide me with information on Ferula Asafoetida. I believe the scientific name may have recently changed. I encountered a huge invasion in Central Asia rangelands and I am not sure how to deal with it from an ecological point of view. I learned that it has medicinal benefits. However, it is avoided and not grazed by animals. Its smell is strong and unpleasant.

    Alok Nahata · Dr. Harisingh Gour University

    Ferula asafoetida is a widely used spice. Besides it is a very useful medicinally. Best quality is believed to be from Afghanistan and Iran. It is an oleo gum resin which exudes out of the rhizomes. Normally it is used as an antiflatulent, digestive aid. Pharmacologically used as antimicrobial, antiasthmatic, antiepileptic and also reported to have contraceptive/abortifacient activity.  

    The strong smell is inherent and characteristic of the oleogum resin. You cannot mask its smell when it is around you. Those who sell it have a strong smell in their shops and later they become adapted to it. I mean to say it is strong but not unbearable.