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  • Mário T. S. Rosado added an answer in Gaussian:
    How do we use scaling factors for the Gaussian calculations?

    I am trying to optimize a basis set and a particular level of theory to reach the experimental results for UV-Visible spectrum. Can anyone suggest how to incorporate the scaling factors for Gaussian calculations? 

    Please help me anyone regarding this issue.

    Thank you in advance.

    Mário T. S. Rosado · University of Coimbra

    Scale factor are used for calculated vibrational frequencies, to compensate for the harmonic approximation, finite basis sets and absent or incomplete incorporation of electron correlation in the theory.

    They are important only for the calculation of vibrational frequencies or their dependent properties, like zero point energies or thermodynamic quantities.

    UV-Visible spectra are related to molecular orbital energy differences.

  • Mahmoud Omid added an answer in Energy Efficiency:
    What are the ways to reduce energy intensity?

    By definition Energy Intensity (EI) is a measure of the energy efficiency of a nation's economy. It is calculated as units of energy per unit of GDP. High EIs indicate a high price or cost of converting energy into GDP. Low EI indicates a lower price or cost of converting energy into GDP.
    Current energy trends of the world are obviously unsustainable, socially, environmentally and economically. EI in Iran’s industry sector is more than 4.6 times greater than world average! (See the attached Chart). Yet, the share of industry sector in Iran is 21%, while the world average is 30%! What scenario would you recommend for her? What infrastructure would be necessary to reduce energy consumption? How your country is dealing with EI?

    Mahmoud Omid · University of Tehran

    Dear Juan, Thank you for the clarification, but what about the differences in Energy Content of various energy sources.  How do they come into play?

    Energy Source    Unit                  Energy Content (Btu)

    Electricity        1 kWh                                      3412
    Coal                 1 Ton                                   28000000
    Crude Oil         1 Barrel - 42 gallons               5800000
    Natural Gas     1 Cubic Foot                        950 - 1150

    Fuel Oil no.1         1 Gallon                                          137400

    Diesel Fuel           1 Gallon                                          139000
    Gasoline               1 Gallon                                          124000
    Heating Oil           1 Gallon                                          139000
    Kerosene             1 Gallon                                           135000
    Pellets                  1 Ton                                              16500000
    Butane                   1 Cubic Foot                                    3200

    Propane              1 Cubic Foot                                        2550
    Wood (air dried)     1 pound                                            8000

  • Vincent Geenen added an answer in Morpholino:
    How can you test B cell development in zebrafish embryos?

    Is there any way to test for defects in B cell development in zebrafish embryos (using morpholinos)? If so, how? Or is the timeframe of morpholino defect too short to assess B cell development?

    Vincent Geenen · University of Liège and FSR-NFSR

    Dear Adrian, you should ask to Thomas Boehm who is an expert in the immune system of the zebrafish.

    Best regards.

  • Krishnashish Bose added an answer in Sorting:
    Is there a way to sort a list of {x,y} coordinates based on both x & y values?


    This list has been sorted based on x-values. I can sort them also based on y-values. But I cannot sort them considering both x & y values simultaneously.

    should be arranged as follows:


    u see that neigbouring points allow only one unit of change in either x,y or both

    Krishnashish Bose · Nanyang Technological University

    Can you check this page: http://mathworld.wolfram.com/TravelingSalesmanProblem.html

  • What is the use of the probability calculation in ant colony optimization? And how the new population is generating at new iteration?

    In ant colony optimization, we are calculating probability based on the pheromone. Still, I have confusion how the new population is generating based on probability?

    Raka Jovanovic · Qatar Environment and Energy Research Institute

    Dear Raja,

    The best way to imagine ACO is as a "smart" randomization of a greedy algorithm. The "smartness", or experience of ants is stored in the pheromone. Finally, the pheromone steers the following randomized greedy algorithms in a good direction.  

  • Does anyone have experience with Longitudinal EM waves and the Maxwell equation?

    I have one problem caused by discrepancy between existence of solution for the EM waves (E ~ 1/R) and the Maxwell equation div E = 0 in free space.

    1. There is Jefimenko's wave equation for the E field (i.e. without introduction of the potentials) [J. D. Jackson, Electrodynamics, 3rd ed. p. 246, Eq. 6.49]. Jefimenko showed that his equation gives a solution containing no terms ~ 1/R corresponding to the longitudinal component. All details of his procedure are given in the textbook of Jackson and for example in [K.T. McDonald. Am. J. Phys. v 65, p. 1074 (1997)]
    But Jefimenko considers too arbitrary dependence of the charge (and current) density on r and t,
    \rho = \rho(r,t)
    and the law of the charge conservation requires the dependence
    \rho = \rho(r -r0(t))
    where r0(t) the law of motion of the charge.
    So this law gives some limitation on Jefimenko's procedure and as a result, it should be a solution for the longitudinal component of the E field ~ 1/R (the longitudinal EM waves). I can explain it in detail but one can read my paper on this subject if she/he wishes: Progress In Electromagnetics Research M, Vol. 34, p.73, (2014).

    2. However, it is known that the longitudinal EM waves cannot exist due to the Maxwell equation div E = 0. It is shown by Zommerfeld [A. Sommerfeld, Elektrodynamik. Leipzig: Akad. Verlagsgesellschaft Geest and Portig, p. 36, (1949)]. Despite Zommerfeld presented his proof for the plane EM waves only and such waves don't exist - there is no such a source that is able to radiate these waves - at far distances the spherical EM waves can be treated as the palne waves with good accuracy. So we can accept Zommerfeld's arguments for the spherical waves too.

    Thus I have a cotradictory resulst:
    - there is a solution of the wave equation for E field ~ 1/R
    - this solution is forbidden by the Maxwell equation.

    If someone could advice how to resolve this contradiction?

    Vladimir Onoochin · Sirius, Moscow, Russia

    On the nuclear bomb explosion as a prototype of the source of spherical symmetry. I hope such explosions (in the air) will not be made in future but it is known that the EM pulse generated by this explosion is very powerful. It damaged electronic devices even they were protected by the metallic shield so crucial units of the equipment should be made with electronic tubes not semiconductors.
    The experimental fact is presence of longitudinal E component.
    Wesley's theory is questionable but he tried to find an explanation of presence of the longitudinal component (Wesley was a person who took part in actual tests so he knew the problem).

    I am not interested in the Maxwell equations (nobody solves these equations but instead uses solutions of the wave equations). However, existing expressions cannot describe the longitudinal component. There is one type of EM radiators, so called Prishchepenko devices. Design of these devices is 'simple enough' but nobody can explain why these devices radiate EM waves in broad band 1 to 10 GHz. Level of power is enough to damage electronics at 50 meters from event of radiation (they are safe for humans). Our spectrometers were supplied to measure parameters of the EM pulses from these devices. Sometimes (despite double shield) our specs were damaged. It is possible if P's devices radiate the longitudinal EM component. 10-50 meters isn't the near zone.
    So when I tried to start from beginning, i.e. from the Maxwell equations, and considered a system containing only longitudinal component, I faced that the Maxwell equations cannot describe propagation of the longitudinal component adequately.

    You can continue to exist that your solution is right (I stated my objections) but it doesn't correspond to the experimental data purified from influence of transverse components.

  • Bill Y Chen added an answer in SPSS:
    Endogeneity problem - How does one solve it using SPSS?

    Dear Community-Members, I hope I will findy an useful comment for my issue:

    I would like to test two theoretical concepts:

    1. Internalization theory --> Estimation Multinationality = Intercept + B*Intangible Assets + B*Controls + u

    2. Transfer costs approach: Performance = Intercept + B*Multinationality + B*Intangible Assets + B*Multinationality*Intangible Assets + B*Contols + u

    I use a Paneldata over 5 years for firms from 4 European countries. Yet, I wondering, since Multinationality and Intangible Assets (from Model 1) are/will be highly correlated, if there will be an endogeneity problem (in model 2)? And if, how I can handle it (e.g. using SPSS)?

    Thank You for Your commens in adv.


    Bill Y Chen · University of the West

    No. To my knowledge, the instrumental approach is different from 2SLS. For INstructmental estimate, you need to find out enough such Instructmental Variables; but for 2SLS, there is specific software to complete the task directly. What you only need to do is to have all equatiopns and indicate wgich ones are Endogenous variables.

  • Syed Muslim Shah asked a question in Beamforming:
    Beamforming in Matlab/ performance evaluation?

    How to simulate a Beamforming system and what are the performance metrics? I am especially interested in adaptive strategies and if there is any Matlab code, I will be very much thankful.

    Best Regards

  • Yasemin Çakırer Özservet asked a question in Crime:
    Do the dead-end streets facilitate or feed crime in their zone?

    What do you think about dead-end streets? Some believe that guilty people can easily hide themselves in these streets and also they can create a closed circuit are with the help of the dead-end streets. Do you agree with it?

  • How can I estimate the photocarrier concentration in semiconductors?

    I need to evaluate the concentration of photo carriers in illuminated thin film semiconductor, e.g. CdTe.

    Suppose I have given:

    I - irradiance of incident light (set as monochromatic for simplicity) in W/cm2

    Q - quantum yield in # of generated electrons/# of incident photons

    E - energy of the incident photon in J

    R - reflectance

    t - relaxation time of generated photo carriers in s

    Can I estimate the order of photocarrier concentration with equation of such form:

    n = (1-R)*(I/E)*Q*t

    In the case of bulk materials (and light of some wavelength range) resulting in an integral over depth, absorption coefficient, wavelength, etc...

    I'm not much into the subject and want to know how much is missing in the upper relation.

    Leonid A. Skvortsov · Polyus Research & Development Institute

    Dear colleagues!
    I do not agree with the above formula, if only for reasons of dimension. Charge in the final expression should not be! The charge appears in the expression for the current. According to Ohm's law, the photocurrent density is j = eμn (x) E, where E - the electric field strength and μ - mobility of the electron.
    Therefore quote calculation estimating the concentration of photoexcited carriers as a distance x from the surface, and its average value over the sample. We will calculate concentration of the photoexcited carriers in the semiconductor in the form of a plate (lxbxa) at radiation it monochromatic light with a power of P.
    (1-R)P/ℏω – the number of the photons entering in 1 second a plate surface (l, b);
    (1-R)P/ℏω exp(-αx) – the number of photons that will remain at a depth x;
    [(1-R)/ℏω] d[Pexp(-αx)]= [(1-R)P/ℏω] α exp(-αx)dx – the number of photons that are absorbed in a layer of thickness dx;
    [(1-R)P/ℏω] α/lb exp(-αx) – the density of photoelectrons generated in 1 second at a depth x (divided expression 3 into layer volume of lbdx);
    In the steady state rate of recombination and generation must be equal, hence:
    n(x)/τ=[(1-R)P/ℏω] (1/lb) αexp(-αx),
    as P = IS = Ilb, then n(x)=[(1-R)I/ℏω] ταexp(-αx) – carrier concentration at a distance x from the input surface in the volume dV = lbdx.
    We find the total number of photoexcited carriers in the bulk of the plate:
    N=∫n(x)dV= [(1-R)Ilb/ℏω] τη = [(1-R)P/ℏω] τη ,
    where η=α∫exp(-αx)dx - value which takes into account the incomplete absorption; а – sample thickness. Easy to see that if the plate was infinitely thick, the factor η = 1. So there is every reason to call the value of the quantum efficiency η.
    The average concentration of the photoexcited carriers then will be equal:
    n ̅=1/V ∫n(x)dx=[1/abl] [(1-R) P/ℏω] τη=[(1-R)I/ℏω] (1/a) τη.
    As can be seen, the dimension of the resulting expression is: (W c)/(W c M^2 M)=1/M^3

  • Caroline Rose Bennett added an answer in Cracks:
    How can I create a crack in a plate that was already meshed ?

    I am trying to create a crack in a meshed model and am looking for a way that I can do that without remeshing.

    Caroline Rose Bennett · University of Kansas

    Yes, the Extended Finite Element Method (XFEM) allows you to insert a crack without needing to re-mesh.  The last few Abaqus releases support this.

  • Veerendra K Rai added an answer in Systems Dynamics:
    There are no events in System Dynamics(SD). There are only closed loop continuous processes. But, delays exist. Is it not paradoxical?

    Why delays exist in system dynamics given the fact that nothing is standstill in system dynamics world? When there is a delay between training and its impact on productivity it is not the case that nothing is happening in the duration of 'delay'; nothing is standstill during that period. Delay is only for the purpose of modeling.

    Veerendra K Rai · Tata Consultancy Services Limited

    Cause and Effect are separated in time and hence the delay. However, this holds for every causal link. In that sense every causal link will have delay. The question is what are the considerations we need to take while modeling delays in system dynamics?

  • Are you interested to cooperate in an Int. Reserch project addressed to evaluate the impact of Person Centered Clinical Method on Clinical Practice ?

    Person Centered Medicine is an epochal change of Medicine, Medical Science and Medical Education whose destiny is to change the quality of Health Care delivery as we have seen in the first pilot investigation of Person Centered Medicine Clinical Method on clinical practice which depicted amazing results.

    You could find it in


    The Person Centered Medicine International Academy would like to spread this investigation all over the world.

    If you are interested in it we could cooperate for realizing the research project we made in your country.

    Prof. Giuseppe R.Brera


    Angélica Baptista Silva · Fundação Oswaldo Cruz

    Dr. Giuseppe, I would like to know about your project. The link http://www.unambro.it/html/Person-Centred-Medicine.ht is broken. The Telehealth Laboratory of National Institute of Women, Children and Adolescents Health Fernandes Figueira (IFF) is interested. We have a large discussion and international cooperation about the issue - social determinants of health. Thank you.

  • What is the minimum number of participants in confirmatory factor analysis?

    There are 55 variables in the scale I am using. How do I calculate how many participants are needed for the study to be viable?

    Miguel A Ruiz · Universidad Autónoma de Madrid

    It is important to ensure that the variance-covariance matrix is well estimated. Usually 100-150 participants are enough for 10-20 variables.

    When possible, multigroup analysis will help testing stability in different subsamples at random.

    Also, don't forget that parameter standard errors will be influenced by small sample sizes raising too wide confidence intervals.

  • John H Carlson added an answer in Primer:
    Before adding the restriction sites, my primers have a 9°C Tm difference but after adding them, the Tm values narrowed. How does this affect my PCR?

    The primers that I designed initially had Tm values of 54.26°C (Fwd primer) and 45.53°C (Rev primer) before I added the restriction sites. After I did that, however, I managed to get the Tm adjusted to 68.59°C and 69.54°C for both the forward and reverse primers respectively. This was done using the Primer-Blast tool. I do realize that the difference in the Tm value is quite large, but I'm not sure whether this will severely affect the PCR.

    Would I have to set a lower annealing temperature for a few cycles first before increasing it to the Ta for my complete primers (including the restriction sites)?

    John H Carlson · U.S. Department of Health and Human Services

    Lengthening the complementary region of your lower Tm primer should bring it up closer to the same Tm as the other primer.

  • Stephan Helfer added an answer in Rust Fungi:
    How did Mielke observe the dispersal distances of rust spores? I would appreciate access to the text.
    There is a citation stating that Mielke documented aeciospore "jumps" of 720km. I wish to verify this for a publication on spore dispersal among other themes.
    Stephan Helfer · Royal Botanic Garden Edinburgh

    Thanks Pascal

    I agree.

  • Can anyone suggest poems that deal with Human-Animal conflict, or similar other issues relating to animals / birds?

    I would locate reading of human-animal conflict in the broad purview of eco-aesthetics or ecocriticism. Poems that deal with the animal worls in my view most often contain an ecocentric worldview. When human-animal conflict arises, what actually happens is a conflict between two prominent worldviews, viz., ecocentric and anthropocentric. The changing patterns of urbanization, consumerism and materialism makes our world more susceptible to such conflicts. I think poetry is a suitable literary poem to search for expressions on such conflicts. Can anyone throw more light on this issue? 

    V.P. Anvar Sadhath · The New College

    @ Asma

    Thanks for the suggestion. I have always been impressed by the way Ted Hughes presented his poems on animal/bird. I was particularly searching for his poems on birds of prey, and found the crow series of poems to be of great use. Another poem I liked very much is "Hawk Roosting"

  • Ludovic Duponchel added an answer in FT-Raman:
    How do we acquire FT-Raman for organic acid aqueous solutions?

    We need to analyze samples of organic acids (including quantitatively) using FT-Raman Spectroscopy. We could easily acquire spectra from crystals of the acids, whereas their aqueous solutions give no signal.

    Is it something related to the laser source wavenumber in my equipment? Which kind of tests can I perform to check if this analysis in solution will be possible?

    Ludovic Duponchel · Université des Sciences et Technologies de Lille 1

    Dear Guilherme,

    If you use FT-Raman, I can imagine that the laser wavelength is 1064 nm. Are you sure the laser power is enough? Indeed Raman scattering is lower when the wavelength is higher. What kind of cell you use?


  • Cinta Gomez-Silvan added an answer in cDNA:
    Which kit for cDNA synthesis do you recommend to be used on bacterial RNA from soils? First strand cDNA from Roche, GoScript, High capacity cDNA?

    I used First strand from Roche when working with yeast RNA, but it is too expensive compared with others. GoScript manual indicates that perform high yield RT also in the presence of inhibitors so as now I am working with RNA from environmental bacteria I took it into account.

    Cinta Gomez-Silvan · University of Granada

    Hi, we are using SuperScript II or III from Invitrogen, it's easy and works well with the RNA from soils. Used the obtained cDNA, after purification, for PCR just in the same day or keep it for a couple of days in the fridge, at 4C.

  • In your country what energy source (residential use) is most used:NG or electric energy?Gas network has 100%coverage? What factors determine this?

    In São Paulo, the most important city in Brazil, there is a difference of nearly 100 years between the expansion of the electricity network and natural gas (NG) distribution pipelines.

    The gas only gained momentum since 2000, while the electricity followed the development of neighborhoods.

    The use of electricity Is still the predominant, based on the following factors:
    -The energy matrix based on the use of hydropower and on the electricity that they generated;
    -Electric energy tariff is still lower than gas;
    - Many houses and buildings have no facilities adapted to use gas.

    There are reports / papers on this subject?

    Thank you for helping!

    Ajay Singh · IIT Kharagpur

    In India, Natural gas (LPG) is the most commonly used because of its availability and government support. This is also because it is highly subsidized, which is one of the most important acceptable criteria in a country like India.

  • Does anybody know how to screen all the chemical compounds found in the herbal plant?

    I need a proper method how to prepare the sample before I run them through GC-MS analysis.

    Majid Mohammadhosseini · Islamic Azad University of Shahrood

    To screen all the chemical compounds found in the herbal plant, there are so methods in the literature. To identify the chemical profiles found in the extracts of the medical plants, I can mention the diverse chromatographic methods. However, as it is customary in the literature, to recognize and characterize the profiles of the essential oils, undoubtedly the GC-MS is the best approach. In short, we can refer to three main criteria in this field involving:
    1) Matching their indexes
    2) Matching their MS fragmentation patterns
    3) The reports of the GC- MS library with a resemblance more than 85%

  • Aleksandra Stańska asked a question in Mannitol:
    Does anyone know something about cognitive functions in patients treated with chemotherapeutics and mannitol which is disrupting blood brain barrier?

    Hello everyone! I'm really curious how does it work and how does it improve some cognitive functioning in patients with brain tumors. Thanks in advance. 

  • Rahul Agarwal added an answer in Gene Ontology:
    How do you perform a gene ontology with topGO in R with a predefined gene list?


    I was wondering if the following approach is correct:

    - I have a predefined list of the Ensembl gene IDs (n=28) and I want to perform Gene Ontology using topGO in R.

    - I don't need to use expression values, but I do need to set a universe of genes. For that I chose all gene IDs available in Ensembl (n=64769)

    If needed, the code can be provided.


    Rahul Agarwal · GenXPro GmbH

    Easy alternative is Amigo GO db.

  • Hao Li added an answer in Ames Test:
    Why is my compound soluble in DMSO, but precipitating with subsequent dilutions?

    I am doing an enzyme assay and am testing a few compounds. When I dissolve the compound in DMSO (100% DMSO), the compound dissolves, but subsequent dilutions made in water or buffer lead to precipitation.

    Even when the dilutions are done in DMSO, and subsequently added to my reagent mix, it turns milky white (precipitates). Thus, I am not able to take readings (absorbance @ 340nm) for such compounds. I am however using controls for every experiment.

    Could you please suggest any solution for this?

    Hao Li · Stanford Medicine

    One possible way would be to increase the concentration of DMSO in your assay. In general, we try to keep it to <1% of total assay volume, as excess DMSO could interfere with enzyme activity. However, some enzymes can tolerate DMSO quite well (for example, the proteasome) and so you can add DMSO up to 10% assay volume. You should titrate in DMSO for your enzyme before trying this to make sure the activity is not killed.

    Another way would be to try different assay buffers. I don't know what enzyme or conditions you're testing so I can't make specific suggestions. 

  • How do you increase the visibility of published article?

    I'm curious to learn about any additional PR steps you can take to increase the visibility of your published articles. Here are some steps I try to take (in various combinations, depending on the nature of the article):

    • Cite the paper whenever appropriate
    • Post preprint/postprint on arXiv/similar repository
    • Bring a pile of reprints to the next conference
    • Write a press release together with the press office of my university
    • Send announcements out on an appropriate email list
    • Put a paper copy in any academic lunch room I happen to visit

    What am I missing? What are your tricks and secrets?



    David Seamon · Kansas State University

    I disagree that academia.edu is not taken seriously. I also think it is the most useful site to share articles. The site is easy to use, one can post first drafts of work, and receive feedback accordingly. It is also "open source" in the sense that the site is open to everyone. One of the best things about academia.edu is that the thematic-interest lists are generated at ground level--in other words, one identifies key words or phrases, which then become an interest grouping. These groupings are not arbitrarily imposed "from above" but arise from "below." Thus one finds accurate topical interests--in my case, for example, "space and place" or "phenomenology of space and place." I've gained some useful contacts through academia.edu I would have not ever known about otherwise.

    So, I think the comment above suggesting academia.edu is superficial is inaccurate.

    What we as academics are beginning to realize in this digital age is that we do our research and writing NOT to get published but to extend knowledge and understanding. Our main aim should be getting information out, and academia.edu does this in a way that is simple and helpful.

  • Rahul Agarwal added an answer in Exome Sequencing:
    How to perform trio analysis using CLC genomics workbench 7.5 ?

    I have a exome sequencing data of parents and their child. We are trying to identify the candidate genes responsible for some abnormality.I have never used CLC genomics workbench.

    Do I need a licensed version for the trio analysis ?

    Rahul Agarwal · GenXPro GmbH

    I recommend to use open source tools for exome sequencing data like bowtie,bwa-mem, freebayes,gatk,etc. 

  • Manohar Sehgal added an answer in Ammonia:
    Is it possible to decompose ammonia gas by UV Radiation?

    N1mmonia gas has Lambda Max between 212-215 nm. Is it possible to decompose Ammonia [2NH3 + hv ---> N2 + 3H3] using Ultraviolet radiation? If it is possible, how much (power) watt will be required to decompose one liter of ammonia in one minute? How we can increase the rate of decomposition of ammonia?

    Manohar Sehgal · DAV College Jalandhar

    Three parts of this question are:
    [A]Whether 215 will decompose NH3(g)?

    1 kJ/mol = 1.1963*10^5nm
    So 215nm= 1.1.1963.10^5/215=556.42 kJ/mol
    Now heat of formation of NH3(g)[ from lilerature]= -46.1 kJ/mol
    So heat of dissociation of NH3(g) [Reverse of formation]= 46.1 kJ/mol
    Again 215 nm which falls in UV region can decompose NH3(g)
    So the answer to this part is YES.This part ends here.

    [B] Power required to decompose one liter of NH3(g)

    46.1 kJ value is for 22.4 L of NH3(g)
    Heat required/ L= 46.1/22.4=2.058 kJ
    Convert kJ into into kW
    Use the converter below [Reported in the literature].
    1 Kilojoule = 0.000 277 777 778 Kilowatt Hour (Kwh)
    Kilojoule is metric system energy unit (electrical,mechanical,thermal) and equals to 1000 times of amount of work done by a force of one newton to move an object one meter.
    Kilowatt hours is one kilowatt amount of power delivered in one hour. One of the most common usage is billing the amount of energy delievered by electric utilities. The abbreviation is "kWh".
    So 1 Kilojoule = 0. 277 777 778 watt Hour
    And 2.058 kJ = 0.571667 watt hour
    So you need 0.571667 watt to decompose one L of NH3 in one hour .But you want to decompose one L of NH3 in one minute, supply0.571667.60= 34.30 watt in one minute.
    In a way , it is = 0.571667 watt hour= 34.30 watt in one minute

    [C] Conditions to increase rate of decomposition of NH3.

    As it is a photochemical reaction, it is not expectected to be affected by temperature/ pressure [Lechatelier’s principle is not applied]. . Had it been a thermal reaction,we would have applied Lechatelier’s principleand there by it would have been affected by temperature/ pressure
    Again 215 nm energy is more than sufficient to decompose it.

  • Daniel Page added an answer in Discrete Mathematics:
    What attributes should an algorithm have for you to say that it is a natural way of mapping two different structures?

    Suppose you look in a new way at the structure of some mathematical object.
    Given the simplicity and universality of that object, you wonder whether its disclosed structure fits (as a model) the result of a certain function f or algorithm over another structure patterns from another scientific domain.

    Now suppose that through that function/algorithm's lens you find something that might be a common feature between those structures. But it probably is just a misleading coincidence...

    Knowing that maybe you can always find a function f that transforms anything into anything, and that this kind of inquiry can be a time consuming process (program the algorithm, calculate mappings, ajust the algorithm to fit the results, etc..)
    what criteria would you use to decide whether it is worthwile pursuing such tentative matching (through f or a) between the math structure and the pattern from your scientific domain, so that if you do get to find a final algorithm/function that works you can expect it to reveal a natural "law" of nature and not just a coding procedure?

    Would the apparent function/algorithm have to be quite simple/small and look natural?

    Would the apparent function/algorithm have to be totally absent of arbitray steps so that it seems to capture a "logical" map between both structures that you realize it could be no other way, or no smarter way?

    Do you have any other attributes in mind?

    Is this just something that you should never try for being against scientific methodology or even common sense (pick up a model and see where it fits?)

    Daniel Page · University of Manitoba

    I'm assuming you aren't looking at "efficient" algorithms.  Several things come to mind:

    1)  How can you encode or describe a mathematical object?  For example graphs can be described in numerous ways.  

    2)  Does the object involve numbers?  If a description isn't a simple "one-to-one" encoding/decoding, it sometimes works for or against you.  Some algorithms can be build upon reductions that will preserve objects sitting within your entire set (of the structure) but you have to include additional feasibility checks.  For example, if your problem has anything to do with 0-1 Knapsack, try to exploit its Dynamic Programming algorithm.  If not, one common trick is to turn it into a graph or design, if possible.

    3)  From experience and what I normally see in generation algorithms or enumeration algorithms (as this is used all the time there) is that a correspondence is found (you want an IFF relationship usually).  Sometimes (2) can throw a wrench in this step.

    4)  The algorithm exploits (3).  People like myself that do research in this area will try to come up with new ways to do (3), or ways to exploit (1).  If you can do (1) well, your algorithm may be very efficient.  A class of algorithms I want to point out are loopless algorithms.  Take O(n) steps to construct the first object, then O(1) for each consecutive object.  So the running time (if exponential in size) will depend on the size of the set typically---which is pretty efficient if you want the whole object.  There are trade-offs even with this approach.

    Keep in mind the intuition involved with finding the mapping does not always come in the order I gave.  Personally when it comes to attributes, some of the points I made in (4) are relevant, but fundamentally I am not sure if you are talking about properties problems have, or attributes as in a subjective construct that I can't prove something about.  I had a bit of trouble interpreting your question as it was not as concrete as we could make this (entire areas of Combinatorics and Theoretical Computer Science work in this area), but I hope this helps. 

    In closing, here are two handy references that may help you some more.  They cover most concepts ranging from brute-force-and-ignorance to many loopless algorithms:

    1)  (my favourite, very straight to the point and lays out a lot of common and classic techniques these days, a bit harder to get your hands on though) Combinatorial Algorithms,  Reingold et al., 1977.

    2) (a standard text in the area of combinatorial algorithms, very accessible) Combinatorial Algorithms: Generation, Enumeration & Search, Kreher and Stinson, 1998. 

  • Evgueni Ivakine added an answer in CRISPR/Cas:
    Can lentivirus or adeno-associated virus mediated transfer of RNA or DNA be made in plant cell?

    Can viral gene delivery methods be employed in plants? Is there an alternate way to introduce RNA or DNA in plants for genome engineering by CRISPR-Cas system. If a model plant where to be made which already expresses the Cas9 enzyme. So is there anyway by which guided RNA can be transferred to these plant cells already containing Cas enzyme. 

    Evgueni Ivakine · SickKids

    Neither lenti nor AAV can infect a plant cell, however, there should be plant viruses that can be used for this application. 

  • Adhidesh Kumawat added an answer in BET:
    What is the difference between total surface area and BET surface area?

    Pleas explain what the difference is between total surface area and BET surface area. Which one is more accurate?

    Adhidesh Kumawat · Indian Institute of Technology Bombay


    Total surface area is the actual "total" surface area regarding the substance you might be talking of, and as in BET, it provides you with the surface area that it calculates based on the adsorption of a gas on the substance exposed surface, withholding some assumptions:

    1. the adsorption is monolayer,

    2. the adsorption is specific to one molecule per adsorption site,

    3. all the adsorption sites have equal accessibility to the adsorbing gas molecules and the adsorption of all molecules is identical, and so on.

    ..it is only because of these assumptions the total "actual" surface area may deviate from the determined BET surface area, but as far as the physical restrictions to find out the surface area of samples, BET has been proven to be very close to the actual value and dearly accurate.