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  • Harith Al-Moameri added an answer in Foams:
    Physical blowing agent efficiency for polyurethane foams?

    Is there any research that discusses the efficiency of physical blowing agents for polyurethane foams? 

    Harith Al-Moameri · University of Missouri


    I want to thank everyone answer my question.

    I want to give more clarification to my question. The system I have is PU rigid foam and the goal is to find out if there are some research that address the efficiency of the liquid physical blowing agent (LPBA) that is used in the formulation (not specific one).

    I define the efficiency of LPBA as: the number of moles of LPBA that is evaporated and went to foam cells divided by the initial amount in the recipe.

    For the viscosity effect, I did a research to include its effect.

  • Detlef H. Rost added an answer in Child Psychology:
    Which reliability coefficient should I use for test-retest reliability of a cognitive assessment for children?

    I'm looking to measure test-retest reliability for a pair of cognitive assessments for children. I recently came across the article by Vaz et al. (2013) article in which they suggest using indices of absolute reliability (e.g. coefficient of repeatability (CR), smallest real difference (SRD)) over indices of relative reliability (e.g. pearson r, intraclass correlation coefficient (ICC)). Now I'm not sure which to use. I appreciate any guidance!

  • Jeffrey P Jones added an answer in Detoxification:
    Any suggestions with the Interpretation of P450 activity assays?

    I appreciate anyone who has thoughts or commentary about the interpretation of some preliminary P450 activity data, as I am certainly no P450 expert. I've had to resort to using spectrophotometric methods to detect P450 activity as flourometric substrates are very expensive. I am interested in looking at several activities of P450s (as their activities are incredibly variable) so I've used the classic PNOD (O-demethylation) as well as a more obscure method I found (N-demethylation) using 4-chloro-N-methylaniline. It is difficult, but possible, to detect PNOD activity with my insect as that activity is fairly low. However, I can reliably detect product with the N-demethylation assay. So here is where I get to my question. We actually haven't detected compounds in my insect's host that would have this structure (N-CH3; e.g. alkaloids), and we have looked. This doesn't mean there are none, but I don't think it is very likely. So what am I seeing? The insect clearly expresses this activity (much more so than the PNOD activity), am I just detecting some sort of steroid synthesis or other endogenous metabolic process of P450s? Would I actually be safe to refer to this as a "detoxification" activity? Any thoughts would be appreciated, thanks for taking time to read this!

    Jeffrey P Jones · Washington State University

    You have a mix of P450 enzymes.  You are most likely looking at one of the xenobiotic metabolizing enzymes since the P450 enzymes that work on steroids and other endogenous substrates are normally pretty specific. It is difficult to know which one unless you do more experiments.  These xenobiotic metabolizing enzymes are non-specific and you do not need to have any equivalent type of compound that is endogenous.   N-demethylation reactions are one of the easiest reactions and DMA is metabolized by  a number of enzymes in human.   

  • Susan Cormier added an answer in Ichthyology:
    Any recommendations for an aquarium chiller?

    I need a chiller for an aquarium re-cycling system of about 250 L with a temperature range of 14-20 degrees Celsius (room temperature 20-25 degrees Celsius). Any recommendations for a reliable unit? Thanks!

    Susan Cormier · United States Environmental Protection Agency

    Frigid units

  • Synthetic Gray Water formulation?
    Does anyone have a recipe for making a synthetic gray water matrix: surfactants, TSS ~80-160 mg/L, COD 200-400 mg/L, BOD 130 – 380 mg/L? This is for a water reuse study.
    Vukani Mthokozisi Khumalo · University of KwaZulu-Natal

    this is how i made mine for my project!

    Tap water (ℓ)                            19.98
    Soap (g)
    Multi-purpose green bar             14.4
    Body-care soap bar                     4 
    Hand-washing laundry powder 12.8
    Fats and greases

    Cooking oil (g)                            0.3
    Food product (carbohydrate and protein) (g)
    Cake flour                                    2
    Nutrient broth                              2

  • ho sheau chin asked a question in HTML:
    Is total reducing capacity same as total antioxidant activity?

    I wish to use this total antioxidant capacity assay kit - http://www.biovision.com/total-antioxidant-capacity-tac-colorimetric-assay-kit-2834.html 

    And I wish to compare the result for total reducing capacity in http://pelagiaresearchlibrary.com/asian-journal-of-plant-science/vol4-iss2/AJPSR-2014-4-2-31-41.pdf

    So, I want to know is total reducing capacity same as total antioxidant activity? 


  • Amin Ghaderi added an answer in PSCAD:
    Query regarding PSCAD/EMTDC software?

    I m doing my research work by using PSCAD/EMTDC software. I have so many doubts regarding PSCAD software. Please help me If anyone knows details about this software.

    Amin Ghaderi · University of South Carolina

    PSCAD/EMTDC is a professional power system simulation software. It is very powerful in time-domain analysis of the power system. Different aspects of power systems, such as, protection, line design, renewable energy resources, etc., could be easily simulated using the PSCAD. Reading its user manual could profoundly help you understand the PSCAD features.
    Please find the following link:


  • David Spector added an answer in Anxiety Disorders:
    Chronic stress leads to anxiety or depression?

    Chronic stress can lead to anxiety in some people, while it can lead to depression in others. Some people with chronic stress may experience both anxiety and depression. It seems not clear how stress, anxiety, and depression contribute to each other. How can we interpret these different combinations of co-morbidity?

    David Spector · Natural Stress Relief, Inc.

    Dear Mariam Ahmad,

    I must apologize that I fell into a bad habit of generalizing the clinical experience as it happens in my country (USA). I did not even think that perhaps another country could possibly be so dramatically different in how patients are treated. But now that I have read your response, I realize how ignorant I was, which is why I apologize for making assumptions.

    I can understand how limitations of budget and of personnel could make a big difference in patient treatment options.

    But I wonder if the difference here is more in history, belief, and institutional politics rather than in economics. I say this because the cost to cure or manage a PTSD patient by putting them into inpatient care is enormous as compared with the very low cost of teaching them transcending, which is a simple and natural mental technique, and enrolling them in a peer-support or similar supportive situation.

    The USA Veteran's Administration is currently investigating whether transcending (using Transcendental Meditation in this case) can serve as an effective therapeutic intervention for the management or cure of PTSD. If the government of our country can pay attention in this way to research results and economics, why cannot the government of your country likewise consider this low-cost alternative?

    Similarly, the cost of several rounds of ECT is much higher than outpatient procedures common in our country, such as medication, psychotherapy, and, again, inexpensive alternatives such as learning the practice of transcending.

    I teach transcending to a variety of clients around the world as a nonprofit organization for less than fifty dollars per client. This is a truly cost-effective intervention. Several doctors and mental health professionals in my country send some of their patients to me for instruction in transcending, and they testify to the effectiveness of this technique for directly dissolving stored stresses.

    If you are correct, and economics is the guiding principle in your country for the very specific treatment practices you have described, then questions and concerns arise that would not arise if the reasons for these choices are determined instead by history, beliefs, and politics.

    In any case, I find it interesting that treatment approaches are so different in different parts of the world, and I hope that the patient and his or her recovery come first in your medical system's list of priorities. People and their recovery should come first, in my opinion. I apologize for my expressing my opinion so openly and readily, and hope again that you will accept my apology for my behavior and my passion for patients.

  • Shikder Saiful Islam added an answer in Shrimp:
    How is sperm alive in thelycum of female penaeid shrimp until shed off exoskeleton during next moulting ?

    Penaeid shrimp physiologist/biologist

    Shikder Saiful Islam · Ghent University

    It is Penaeid shrimp, Penaeus monodon. They are closed thelycum species and sperms remains protected there. Evolutionary sperms are capable to be alive a long time and sequentially fertilize the eggs up to several spawning. But after first spawning the viability of sperm going to be reduced gradually.

  • Guy Roemer added an answer in Oil Palm:
    Are there any research details or studies relevant to water quality and ground water table affected by oil palming?

    Any publications related to water contamination or reduction by oil Palming?

    Guy Roemer · Tetra Tech

    I would start with this paper:


  • Angus Chu added an answer in Bioremediation:
    Is there any kinetic model relating bioremediation rate to temperature, pH, Depth & Nutrient?

    Good day all.Is there an established single kinetic model relating bioremediation rate to temperature, pH, Depth & Nutrient? If not how can I model one?

    Angus Chu · The University of Calgary

    No there is not a single one.  Temperature can use arrhenius relationship.  It predicts a rough double reaction rates with every 10C rise in temperature.  We proved that comparing crude oil degradation in column studies camparing 5 and 20 C, the rates were essentially the same.  pH affects reaction rates dependent on whether the population are acidophiles or not.  Most bacterial populations prefer neutral conditions for optimal activity.  Nutrients are basically modelled using monod kinetics.  I have no idea of how you would go about modelling depth.

  • How do I analyze differences in cumulative mortality in treated and control insects?

    We assessed the impact of disturbance on captive insects over time. Mortality occurred in 2 species in both control and disturbed conditions. 

    The cumulative mortality rates vs time for controls and treatments are clearly separated. Hence we think they suggest the disturbance has had a negative impact.

    This was an undergraduate pilot study and whilst 24 insects were in each treatment and each control we were unable to provide replication due to lack of resources. We tried following individuals for e.g. body wt as a proxy for condition but this proved unreliable. 

    We want to write a short communication for zoo keepers about this, as literature searches show very little research in this area for inverts/insects. We know the work has flaws but the audience are likely to be non-scientists, and we want to raise awareness of possible impacts and present the data in an appropriate way. It is unlikely to receive the rigor of peer review of e.g an entomological journal, but nevertheless we'd like it to be presented as best we can, and to encourage further research.  

    Any comment would be gratefully received, including target publications

    Ravikumar Jayachandran · Regional sericultural Research station

    Henderson and Tilton's formula would be appropriate to nullify the mortality in control also so as to find exact corrected mortality in the treated one.

  • Anyone familiar with Null Hypothesis in Granger Causality Wald Test with THREE series ?

    How to pose Null Hypothesis with three time series while carrying out Granger Causality Test ?


    Raja Fawad Zafar · Pakistan Institute of Development Economics

    it same like two series test. Third series is included just as a control variable, so its inclusion does not change hypothesis

  • Manuel Rodríguez Medina added an answer in ANOVA:
    I need help on DOE Analysis. Why are there no significance factors among them?

    I had design an experiment and it is a 2k matrix approach, 2^4(4 factors,2levels) x 3 replications = 48 runs. Total output is my response in study. The range of output falls in between 5000-8000. The analysis using minitab shows that there is no significance factor among each combination and individual factors. Any way I could change the situation ?

    Manuel Rodríguez Medina · Instituto Tecnológico de Ciudad Juárez, Ciudad Juárez, Chihuahua.

    you must remove the analysis less meaningful interactions and will return to perform the ANOVA.

  • Is graphene quantum dot fluorescence will be completely turned off after immobilization of enzymes on it?

    We want to measure the protein inhibitor of the enzymes used.i need to know after enzyme immobilization graphene quantum dot will be completely turn off?

  • Ana Calobra asked a question in Arteries:
    Can anybody tell me good articles about the difference between complications observed in PCI via transradial artery and femural artery?

    I want articles that compare the most significant complications observed between percutaneous coronary intervention (PCI), and articles that study what complications are more related to the PCI via the radial artery and the femoral artery. Also what strategies could we (nurses) use to prevent those complications in our patients. 

  • 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.

    Bernd Schmeikal · University of Vienna

    How perceive the other?

    "We can see other people's behaviour, but not their experience. This has led some people to insist that psychology has nothing to do with the other person's experience, but only with his behaviour.
    The other person's behaviour is an experience of mine. My behaviour is an experience of the other. The task of social phenomenology is to relate my experience of the other's behaviour to the other's experience of my behaviour. Its study is the relation between experience and experience: its true field is inter-experience." (Politics of Experiece, RDLaing)

  • Sadeem Fadhil added an answer in General Relativity:
    Can the light postule in General Relativity be seen in a different light?

    In General Relativity there are only two basic concepts that run the logical path to the theory.

    1) The principle of Relativity: The was first put forward in the late 1500's and early 1600's by Galileo Galilei.  It is a statement of the understanding of science to be the same for all freely moving bodies.  Einstein imbedded this in the social network of science and it seems the logical conclusion.

    2) The light postulate:  Einstein carefully crafted this definition to match what he thought about light and its unusual property of always being seen at the same speed no matter where you were or how fast you were going with respect to its starting point.       Simply: The speed of light is constant in a vacuum because the speed is independent of the source that emitted the light and therefore always constant.  This changes time to be variable.

    The implications of course where that time and space as the variants and light is the constant.

    Could not this be stated much differently?

    Gravity affects light.

    Many ideas are needed but the theories ability to calculate and or predict things traveling through space and time are not changed by these ideas.  It however does change the understanding of space and time to more closely match reality.  The twins paradox will go away.

    The affects of space are still warped by heavy objects moving through it.  Time is still affected by our ability to measure it in the presents of gravity.  

    However, it changes the perception of time being warped to time being harder to read accurately.    It also raises more questions about why we see light at this speed.  Are there simple answers to this question?  

    Sadeem Fadhil · Al-Nahrain University

    Dear George

    I think both SR and GR need a real modification to interpret many phenomna in physics not to count many, Vacuum Cherenkov radiation, EPR paradox, Unification between GR and QM. .. etc

    I have answered the second in my paper which is found in my profile in RG. In addition I have answered the first in another paper, but I really facing a strong opposition from editors to accept it in spite of giving them real evidences. The third one I believe the new theory can achieve it in a simplified way. The only problem is with the stone minds that do not accept any think new. I think this will be changed soon after realizing that the physics should also develop as well as other branches in science. Its physics right  to be developed!

    With best regards


  • Michael Ferreyros asked a question in QIAGEN:
    What is the best Long PCR Kit? Life, Qiagen or NEB?

    I am looking to amplify a roughly 12kb amplicon and want to know which kit requires the least amount of optimization. Any advice is welcomed!!

  • Joshua Lobo added an answer in Standard Deviation:
    How do I normalize 2 grayscale images so that they are equivalent to each other?

    I have 2 grayscale images which have the same maximum and minimum values and are represented by 256 grey levels. the averages of two images are different.The standard deviations of the two images are also different .Is there a statistical method where I can make the averages ,standard deviations as well as both the minimum and maximum values the maximum values the same so that the 2 images become equivalent?

    Joshua Lobo · Virginia Commonwealth University

    So just to clarify what I want to do and what I did

    I have two grayscale images say G1 and G2 and I have the values of minimum ,maximum mean and SD for both. I am trying to make G2 comparable to G1 for which I used an arithmetic scaling method and was able to get the min and max values of G1 and G2 to match but not their mean and SD.

    I think for them to be comparable I would have to match their mean along with their max and min at the least and min,max,mean and SD as the best case scenario.

    @Sambasivarao how would you suggest I make the min max and mean the same for my 2 images ? .

  • Does anyone have any references for the environmental performance of tall office buildings ?

    Am also interested in the following with respect to tall buildings in urban situations:

    cost/benefit analysis of development,

    MFA analysis over lifespan of construction/operation/demolition,

    macroeconomic analysis of development and operation,

    infrastructural upgrades within existing urban contexts?

    Marco Antonio Benavides López · National University of Colombia

    Stephen, the structural synthesis to make a building part efficient and independent from the design process; First, the orientation to the sun (stations) for maximum use of natural light, adequate ventilation; important energy saving from LED system; use of materials that capture heat or prevent the facades; covered with photovoltaic panels, natural systems refiregarción from concpeto of a green building. Fundamentally, the location, orientation, materials and the will of the owners bet on the construction of a sustainable building. Hits. 

  • What is the structure in this image?

    I am saying this as a nanoporous

    Manikandan Mayilmurugan · Bharathidasan University

    thanks for your suggestion sir, can you say the structure of this?

  • Lang Peng asked a question in Computation:
    Partially solve an equation?

    suppose I have an equation of M unknowns, but I only need very small part of it, like sqrt(M), Is there an efficient way of solving this small part of unknowns without solving the whole equations then pick up those unknowns. As we know, solving an M unknown equation take O(M^3) operation. I was hopping to lower to computational cost radically since I only need sqrt(M) unknowns.

  • Tim Peters added an answer in Troponin:
    What is the best time point to assess PKA target phosphorylation after stimulation with isoproterenol?

    I would like to assess phosphorylation of PKA targets like phospholamban and troponin in isolated rat cardiomyocytes after stimulation with isoproterenol. Is there an optimal duration for stimulation to get detectable but not yet maximal phosphorylation?

    Tim Peters · Maastricht University

    Thank you very much for your suggestions. I did not consider activation of phosphatases. Thanks for the hint, Kenneth. Making a time course with increments of 30 seconds is a good idea.

  • Fakiha Komal Arshad added an answer in Curcumin:
    How can I perform DPPH test using ascorbic acid and curcumin?

    I would like to know the procedure. Does it work with water taken as solvent?

    there are many protocol available on online paper. brands-william protocol is one f them. follow it, i think DPPH is not soluble in water, yes methanol is the best solvent for DPPH.

  • Bikram Keshari Senapati asked a question in Sex:
    Irrespective of age, sex, religion or geography, why man is abnormally exhibiting sex related behavior in professional and public life?

    Sexual behavior is one of the universal factor for selection of a successful partner. This is for normal partners for rearing family. Evolution has put an ultimate directive to the life form to perpetuate so that environmental interaction will try with the best gene-pool left by a species for successful inheritance.

    But sexual exploitation is becoming rampant in different walks of life whether public or professional, whether developing or developed countries, and creating sociological problems. Does it indicate something for future success or failure? Is it a desperate attempt to survive through stressed environment or a warning bell for a dooms day?

  • Can any one identify this species?

    I have collected this species from the coastal areas of Gujarat state which is located on the north western corner of India. 

    Shikder Saiful Islam · Ghent University

    it is a hermit crab.

  • Letian Wang added an answer in Grain Boundaries:
    How can one find out the chemical composition of the thin film in grain and the grain boundary region?

    How one can find out chemical composition of al doped ZnO thin film on Glass substrate in grain and grain boundary region?

    Letian Wang · University of California, Berkeley

    for the grain boundary in a thin film, I recommend the EBSD (electron backscatter diffraction).