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  • Otto Brinkkemper added an answer in Sorghum:
    Does anyone have C&N isotope values for sorghum immediately available?

    I'm looking for C & N isotope values for sorghum (conventionally grown) to assist in calculating mass balance corrected food isotope values. I'm struggling to wade through the literature and have all the other "food" values I need; so anyone with these data at their fingertips please respond. (It may result in your paper being cited if I use the values!). Thanks

    Other food items I'm using include; sunflower, maize, beans, sweet potato, butternut, carrot, apple.

    Otto Brinkkemper

    If there don't pop up data for Sorghum, you could consider adding data from a comparable C4 plant (with the same type of photosynthesis that results in a relatively low discrimination against 13C) broomcorn millet (Panicum miliaceum), depending on the error margin you are willing to accept.

    For the Netherlands, an initial project included two millet samples (and a total of 22 archaeological samples of charred plant remains), which were measured for delta13C and delta15N after acid-only, acid-base-acid and no pre-treatment. Both samples date to the Iron Age (800 - 12 BC). I can provide you with the isotopic data on request.

    Our measurements also indicated an interesting trend through time for the total group of cereals, which we are currently investigating further with more samples. If this remains the case, it will be very hazardous to include data from greater distances (in time, but possibly also in space) into models for particular sites.

    With kind regards,

    Otto Brinkkemper

  • Zneidi Salma added an answer in Service:
    How can revisit intention in service sector be measured?

    I am wondering if there are any papers dealing with this topic and what scales have been developed for measuring it. It will be great !

    Zneidi Salma

    Thanks every one ! 

  • Ali A R Aldallal added an answer in LDH Assay:
    How do I standardize the LDH activity to protein content per well for my LDH assay?

    I am going to be running a series of cytotoxic assays one being LDH assay which I have not done before. I have been told that I need to standardize the LDH activity to protein content per well but I am unsure on how I go about doing this any suggestions? 

    Ali A R Aldallal


    Try to use this link......Its free article

    Best wishes

  • Braz Calderano Filho added an answer in Soil Classification:
    What is Inceptisols according to WRB classification?

    In my study site soil classification according to Soil Taxonomy is Inceptisols.

    Soil type is clay-loam.

    Horizon A: Depth= 0-15 cm; Sand= 33%; Silt= 41%; Clay=26%.

    Horizon B: Depth= 15-55 cm; Sand= 29%; Silt= 43%; Clay=28%.

    Horizon C: Depth= 55-85 cm; Sand= 26%; Silt= 42%; Clay=32%.

    The study site have Marl and Limey sand-stone.

    The parent material is calcareous and soil is leached brown forest soil.

    Braz Calderano Filho

    Dear Ahmad,

    As the American System of Soil Classification (Soil Taxonomy, 2006), the suborder Udept refers to Inceptisol (ept of Inceptisol) with údico water regime (ud údico). The ud grouping udico + ept of Inceptisol results in Udept.

    In the American system, the order of Inceptisols correlates with Cambissolos the Brazilian Soil Classification System (Embrapa, 2006) and World Reference Base (WRB).

    The concepts of the Brazilian System of Soil Classification EMBRAPA were based not only on the American System classification system as well as in the FAO classification system. In 2006 it published a revised and expanded edition of the Brazilian System of Soil Classification -Sibcs (Embrapa 2006).

    The order of Cambissolos
    The Cambisol is a land undeveloped, with incipient B horizon. Soils are "young people" who have primary minerals and high silt even in the surface horizons. The high content of silt and shallow depth make these soils have very low permeability.

    Example of framework of cambissolo by US classification systems, Brazil and Internacional (WRB):

    Soil Taxonomy (EUA,1999) = Inceptisol
    Embrapa (2006) = Cambissolo
    WRB (1998) = Cambisol
    Soil Taxonomy (EUA,1999) = Ochrept ou Umbrept
    Embrapa (2006) = Cambissolo háplico
    WRB (1998) = Dystric ou Eutric ou Cromic Cambisol


  • Mark Hahn added an answer in EEG Analysis:
    Can we measure the low frequencies (e.g. Alpha), if we have a high sampling rate (e.g. 2000 samples)?


    I recorded the EEG raw data for 5 minutes. It has 2000 samples and I need all of them to know how the frequencies change during these 5 minutes. So, I converted these raw EEG values to voltage (Micro Volt) and then I got FFT of all these samples. But something abnormal happened. After getting the Fourier Transform of these data samples, it shows me just the frequencies between 4-8 HZ !. It means it just shows the Theta Frequency Band (4-8 HZ)

    Now, I have a serious doubt about sampling rate.

    First : Why I can't get the other frequencies like Alpha (8-12 HZ) or Beta (12-25 HZ)?

    Second : I havea lot about sampling rate but it still seems unclear for me. So, what is the exact meaning of sampling rate? In my data, I have 2000 raw EEG points and I used all these 2000 points to get FFT. So, does it mean that my sampling rate is 2000

    Third: It has always been said that if we want a specific frequency bands, based on Nyquist theorem we need at least 3 times sampling rate of the frequency that we want to observe. So, this is the question : If we want Alpha (8-12), we need 36 (12*3) samples. But what if we have 100 sampling rate? Based on this theorem this sampling rate is sufficient for getting frequency with 30 HZ. So, what about the frequencies less than 30 HZ? By having 100 sample rate, can we observe the lower frequencies like Alpha or Beta?

    Mark Hahn

    When you sample at 100 Hz, you are able to detect a sine wave of up to 50 Hz.  But think about it: that 50 Hz signal has 2 zero-crossings per cycle.  So if you sample at those instants, you'll (falsely) see zero amplitude.  But you'll accurately measure the signal if you sample at 90 and 270 degrees.  Further, suppose the signal is actually at 51 Hz: now you'll see a 1 Hz signal.  This is aliasing, and is why you must not only respect Nyquist (choose a higher sampling rate), but also low-pass filter your raw/analog data before digitizing.

  • Kamar Eleanor Ameen-Ali added an answer in Evans Blue:
    Can I carry out immunohistochemistry on mouse tissue when the mice have been previously injected with evan's blue?

    I would like to use evan's blue to assess blood brain barrier permeability in my Alzheimer's mice, but I would like to know if the same tissue can be processed   for DAB or fluorescent immunohistochemistry using Iba1 or GFAP primarys, for example.

    Kamar Eleanor Ameen-Ali

    Hi Mohamed, thank you that is extremely helpful!

  • Azmi Kamardin added an answer in Argon:
    Why on earth copper-graphite composites expand after conventional sintering process?

    Copper was in powder form, graphite was in fiber form (150microns), uniaxial compacted in 12mm mold under 5 tonnes of load. Sintering at 900 deg C under argon atmosphere. 

    Azmi Kamardin

    Roman Kubrin, thank you for your answer. You just make my day upside down. As crazy as it sounds, Copper acetylide is also a possibility because my sample has high sensitivity and reactivity towards water. 

  • Artur Braun added an answer in Earthquake Seismology:
    Can the same seismogenic fault generate a future earthquake, and what about the energy accumulation along a fault?

    seismic, fault, earthquake

    Artur Braun

    We do not have to predict an earthquake along a fault.

    Let's just look back in history and count the events. The observation is statistically significant and you can tell there are faults which are accompanied by frequent quakes.


  • Emil Berengut added an answer in Manual Therapy:
    Can physical therapists actually break up scar tissue?

    There is much research in pain science that PTs don't actually break adhesions and any manual therapy that causes a release is a neurological function. I'm a little unclear if that's still the case with scar tissue

    Emil Berengut

    Ralph, that appears to be the theory. In addition, I believe that manual therapy enhances therapeutic alliance, increases time spend one on one with the patient and a creates opportunities to educate and relate about their experience. All of which helps to modulate pain perception.

    Fuentes J, Armijo-Olivo S, Funabashi M, et al. Enhanced Therapeutic Alliance Modulates Pain Intensity and Muscle Pain Sensitivity in Patients With Chronic Low Back Pain: An Experimental Controlled Study. Physical therapy. April 1, 2014 2014;94(4):477-489.

  • Emilija Jasovic-Siveska added an answer in Analgesics:
    What analgesics can be used for severe pain during pregnancy?

    what  does the literature say about safety of analgesics during 1st and last trimestor of pregnancy? mild pain can be relieved with paracetamol or acetaminophen but for severe pain what to do. 

    Emilija Jasovic-Siveska

    I agree with Dr Svendsen, and I have same thought.

  • Chithan C Kandaswami added an answer in Riboflavin Deficiency:
    What happens when riboflavin is deficient in humans?

    What happens when riboflavin is deficient in humans?

    Chithan C Kandaswami

    Riboflavin deficiency is associated with cheliosis and angular stomatitus (lesions of the mouth) and dermatitis, as Jan stated above. However, many of the deficiency associated symptoms can result from conditions other than the lack of a vitamin. In view of this and and because vitamins are needed only in relatively small quantities,  pathological conditions that are considered to arise from vitamin deficiencies are generally difficult to diagnose.

  • Nancy Wright added an answer in Literacy:
    Can anyone recommend Canadian/Quebecois novels thematizing public primary and high school education and related social services?

    I am interested in Canada's literacy statistics and whether they may be skewed.

    Nancy Wright

    Thank you so much Wolfgang!! This does sound like a fine read and from an immigrant perspective... wonderful!



  • Glen Ellis added an answer in Electronics and Communication Engineering:
    What is the truth about the exotic current feedback amplifier? Is it something new or just a well known old? Is it really a current feedback device?

    When discussing whether there is a connection between the transistor common-base stage and the op-amp inverting amplifier...


    ... Prof. Lutz von Wangenheim gave as an example the so-called "current feedback amplifier" (CFA). I have ever met this weird device, but I did not pay attention to it because I just did not understand what the hell all these absurd connections were (an output to output instead to input?) contradicting the simple engineering logic. Now it was enough to cast a glance at its internal circuit diagram (the attached picture below) to be amazed and admire this great circuit solution! This was a chain of ingenious ideas, a real "necklace of diamonds"! Just to see how beautiful, simple and symmetrical its circuit diagram is enough to admire it!

    It was very interesting for me to see in this "cocktail" of famous circuit solutions some useful implementations of basic circuit ideas that have arisen for consideration in a number of previous questions:

    https://www.researchgate.net/post/Can_we_apply_the_input_voltage_to_the_output_of_a_voltage_follower_instead_to_its_input_and_to_take_the_current_as_an_output_Is_it_correct (the general idea)

    https://www.researchgate.net/post/Can_we_see_the_negative_feedback_principle_in_the_operation_of_the_common-base_stage_Can_we_think_of_it_as_of_a_disturbed_common-collector_stage (the specific transistor idea)

    https://www.researchgate.net/post/Can_we_apply_an_input_current_to_the_collector_of_a_BJT_whose_base_is_held_at_a_constant_voltage_and_to_take_the_collector_voltage_as_an_output (the general dynamic load idea)

    https://www.researchgate.net/go.Deref.html?url=http%3A%2F%2Fwww.circuit-fantasia.com%2Fmy_work%2Fconferences%2Fcs_2005%2Fpaper1.htm (dynamic load implementations)

    http://www.circuit-fantasia.com/my_work/conferences/cs_2005/paper2.htm (the differential dynamic load idea and its implementations)

    https://www.researchgate.net/post/What_does_biasing_mean_and_how_is_it_implemented_in_electronic_circuits (the ubiquitous biasing idea)

    But what was my surprise when browsing through reputable source? I noticed that instead of being made related to the classical tricks widely used in transistor circuits, the current feedback amplifier is presented as something completely new. I have not met even a hint of the existence of such famous circuit ideas like "common-base and common-collector configuration", "dynamic load", "bootstrapping", instead, I read direct statements like "the inverting input is its low-impedance output terminal" (http://www.analog.com/library/analogdialogue/anniversary/22.html). But I would be very interested to see the look on the face of the ordinary (unenlightened in the intricacies of the circuit "handicraft") reader when he/she reads that the input of the circuit is... its output!

    So, my suggestion is to try unveiling the clever secrets behind CFA as we go back in the past and try to recreate, step-by-step, the way its creators (David Nelson, Kenneth, Saller Bill Gross etc) have thought when inventing it. If you allow me, I can start the discussion by exposing below my story about the possible reasons for originating this clever circuit solution.

    Glen Ellis

    De Nada.  
    It has been the great pleasure of this geeky geezer 
    to read the thinking of men more talented than himself ,
    and to comment without consequence. 

    Point well made.  
    We casually speak of the "dominant" entity. 

    I only felt that "Rule Number Zero"  
    needed to be brought to the front
    ... if only for a moment. 

  • Ahmed Abdel-Latif Mohamed added an answer in Neutrons:
    How can I verify that the mass attenuation and neutron removal cross section are correlated with a specific element in different compositions?

     I have calculated both of them and made a plot with the chromium  contents and found from the graph that the mass attenuation  and removal  cross section are decreasing. This yield that both of them decreasing with Chromium contents.

    Can I verify  this with another method.

    + 1 more attachment

    Ahmed Abdel-Latif Mohamed

    The iron

  • Mateusz Olczak asked a question in Potassium:
    What is the process and the reaction of potassium sulphate production?

    I need some information about the manufacture of potassium sulphate by the reaction: 2KCl + MgSO4 <-> K2SO4 + MgCl2

    Anyone know some publication or book?

  • Neeraj Srivastava asked a question in Crystallography:
    What is space group ,wyckoff position and occupancy of gamma alumina (cubic).I want to these data for create the phase in ebsd analysis?


  • Austin Brown added an answer in Child Abuse:
    Does anyone know of any studies which link long term recovery from substance abuse and individual improvement in socioeconomic status?

    I am looking at public policy dealing with child abuse and neglect, specifically the role of DCF in dealing with opiate-dependent parents. What I am wanting to show is that long term abstinence-based recovery is linked to an improvement in socioeconomic status if the treatment is comprehensive. And that recovery improves not only the person and their family, but that recovery helps lift families out of poverty.

    Austin Brown

    This is excellent. Thank you.

  • Jaime González-Gómez asked a question in Odontometry:
    Who is the first anthropologist or researcher who used the term odontometry?

    We know of many pioneering researchers in the use of odontometry as a tool, but do you know, what person established this term ? and the first context of its use? Are there references of this?


  • Amirmohammad Pasdar added an answer in CloudSim:
    How can I simulate Rack in CloudSim simulator?

    The is no good resource for learning or unfortunately i cant find , i want to simulate real data center so I need to create rack but i don't know how ?

    Amirmohammad Pasdar

    Dear Yahya,

    In the first step you need to find out the rack characteristics then based on them extend your class. If you can provide more information about your plan, you will get more accurate answers.



  • Ronán Michael Conroy asked a question in Mefloquine:
    Is anyone doing research into long-term incidence of psychiatric disorders and use of Mefloquine (lariam)?

    There seems to be quite a bit of short-term research, but I wonder if anyone out there is doing long-term research – 20-year or 10-year incidence of serious psychiatric disorder.

  • Sergey Bombin asked a question in Mortar:
    What formula could I use to calculate H2O2 based on absorbance?

    I am trying to calculate H2O2 in plant tissue based on this protocol:

    Fresh leaves (0.5 g) were homogenized using a
    cold mortar and pestle in precooled acetone (5 ml) and the
    homogenate was centrifuged at 12,000g for 5 min. One
    milliliter of the supernatant was mixed with 0.1 ml of 5%
    Ti(SO4)2 and 0.2 ml of 19% ammonia. After a precipitate
    was formed, the reaction mixture was centrifuged at
    12,000g for 5 min. The resulting pellet was dissolved in
    3 ml of 2 MH2SO4 and the absorbance was read at 415 nm
    using a spectrophotometer. The H2O2 concentration was
    calculated according to a standard curve of H2O2 that was
    prepared by using H2O2 ranging from 0 to 10 lM.

    But I do not have H2O2 to make a curve. Does it possible to use some formula?

  • Omar S Barnaby asked a question in Oligonucleotides:
    Nucleases/methods for cleaving phosphorothioate modified oligonucleotides?

    I know my question is counterintuitive since these linkages are specifically engineered to prevent nuclease activity. Does anyone know of a method (enzymatic or not) for cleaving these oligonucleotides into predictable fragments? 

    Am not so much worried about the yield, just trying to get an idea of methods at this point

  • Sandile Jabulane Magagula added an answer in Banking:
    The pecking order theory or the static trade off theory, which of these theories are more evident in capital structure decision making?
    Theories of capital structure
    Sandile Jabulane Magagula

    It's a little complicated to pinpoint with great precision. There is evidence in the recent capital structure literature raving about  non-mutual exclusiveness between these theories, The trade-off and information based theories. I further suspect it all depends in a lot of firm specific and institutional factors reflecting macro level conditions in the economy. The choice whether firms follow trade off or information based theories depends on the quality of the stock market firms operate in and of course firm unique condition such as creditworthiness,type of assets held,size of tangible and quantity and quality of intangible assets just to mention a few. Oftentimes ,in high growth prospect , semi-efficient and inefficient capital markets information based theories tend to outclass trade-off theories. Not to mention,there is no definite proxy for such theory tests.

  • Jaime Ramiro Santin added an answer in Air Quality:
    Does anyone know a methodology to measure oxygen production from plants?

    I am trying to measure how much oxygen produce a plant (urban trees) and I need a methodology to do it. Then I want to compare if the quantity of oxygen produced by the plants in a urban area  is enough for the people that live in the urban area. Considering that this place has few trees and many cars. I am assuming the air quality is low due to pollution from cars. 

    I hope someone can help with some methodology, instruments o others similar works that have been done.


    Jaime Ramiro Santin

    Dear Bachir

    I appreciate for your information. By any chance, do ha have a paper where I can find this info. 


  • Hossein Mohammadhassanzadeh added an answer in Software Validation:
    How can I find a software for validating knowledge based systems?

     I implement a fuzzy expert system and i want to validate knowledge base system,

    Is there any free software for validating knowledge based systems ?

    Hossein Mohammadhassanzadeh

    First you need to identify the criteria you want to study. For example, if you want to investigate the performance of your system, they might be some software out there you can use. But, if you want to validate the advice/recommendations that your system provides you usually need an expert for the validation.

    So, your question is so general. First decide what aspects of your system needed to be evaluated and then find the relevant approach/technique/software for the evaluation.

  • Elham Bahrami added an answer in Methods:
    What method of extracting apoplastic and Symplast sap of root cell, suggest me?

    which method is better for extract sap of symplast and apoplast ?

    Elham Bahrami

    Dear Raj

    specials thanks for your attention

    best regards

  • Martine Anne Jaworski added an answer in Pathway Analysis:
    Does anyone else see highly ranked false positives in pathway analysis in their field- is this a systemic problem?

    These pathways were ranked as follows in a reputable journal publishing an article about epilepsy related-genes, with -log (p-value) in bold; followed by p values in parentheses:

    1. (top rank) Molecular Mechanisms of Cancer 9.66 ( 2.188 x 10-10)

    8. Type II Diabetes Mellitus Signaling 6.14 (7.244 x 10-7)

    11. Pancreatic Adenocarcinoma  5.7 (1.995 x 10-6)

    A plausible pathway related to the Central Nervous System (CNS) appeared lower down:

    12. Axonal Guidance Signaling 5.67 ( 2.13 x 10-6)

    Does anyone else see highly ranked false positives in pathway analysis in their field- is this a systemic problem? Do you think it is a significant problem? How do you get around it? (It is possible to run several different pathway analyses, but they are often contradictory, and it should not be necessary to cherry-pick).

    Do you think the problem lies in the realm of biological classification and annotation, and/or the algorithms used, and/or the statistics?

    If this is an important issue, what do you think are potential solutions

    Martine Anne Jaworski

    I notice in an otherwise excellent  paper by a reputable group, the following results in regard to Bipolar Disorder, a neuropsychiatric condition, that their pathway analysis yielded the following in Table 1: (their top 10 pathways, listed by p value) 

          1)   1.01 × 10−6    0.005    GO:51568        Histone H3-K4 methylation                        

          2)   3.82 × 10−5   0.093    path:hsa05218     Melanoma                                         

           3)   1.16 × 10−4    0.093    GO:7129 Chromosomal synapsis genes                                     

           4)  1.27 × 10-4      0.093    path:hsa05213     Endometrial cancer

           5)  1.34 × 10−4    0.093  P00003 Alzheimer disease–amyloid secretase pathway      

           6) 1.35 × 10−4    0.093    path:hsa05215     Prostate cancer                                  

           7)  1.50 × 10−4    0.093    path:hsa05216     Thyroid cancer                                  

            8)    1.59 × 10−4    0.093    GO:90066          Regulation of anatomical structure size           

             9)   1.81 × 10−4    0.093    path:hsa05214     Glioma

             10)    1.87 × 10−4    0.093    GO:70192         Chromosome organization involved in meiosis    

    I can see the potential relationship of glioma, a brain tumor (ranked 9th), but I fail to see the relationship between  bipolar disease and the more highly ranked melanoma (2nd), endometrial cancer (4), prostate cancer(6)  and thyroid cancer (7).  I can see a potential relationship with some of the other ranked pathways. But why do several tumors not even in the CNS rank so high? Something is amiss here.

    Nature Neuroscience 2015 doi:10.1038/nn.3922

  • Flavious Bobuin Nkubli added an answer in Radiography:
    How can we establish paediatric computed radiography technique chart or guides?

    Radiography technique charts or radiography exposure guides have been used over the years as a means of minimizing rejection of radiographs in conventional film-screen paediatric radiography. How useful is this practice with the introduction of new image receptor technology (CR, DR)?

    Flavious Bobuin Nkubli

    Hi Tommy, I am grateful for the lecture materials and additional literature. They are quite rich. I sincerely appreciate. 

  • Daniel Adesse added an answer in Methods:
    DNA ladder apoptosis-no ladder formation
    Hello Everyone,
    I once tried performing the DNA ladder test as a measure for apoptosis. I isolated the DNA using a kit and also quantified it, it was ok back then even purity seemed ok. However when I ran d samples in 1.5% agarose-gel TAE buffer system. I could not see the ladder form. I am wondering about where may I have gone wrong. It should be a simple assay and the whole method is relatively easy but then still got stuck at it. So would like to get some idea as to why might this have happened? Please pass on ur ideas....
    Daniel Adesse

    Hi there,

    I too tried many times the ladder assay using genomic DNA extracted with the DNeasy kit (Qiagen) and loaded 3ug of DNA in 1.8% gel in Orange G buffer. I got the same result as Sanjaya: strong bands on top of the gel and no fragmentation. I did positive control incubating the cells with Staurosporine and still no laddering was observed...

    Any suggestions?

    Thank you!