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  • Does any body Know about PhCH2CH2Br?about its organic properties?

    Hi every body, I want to compare the rate of PhCH2Br and PhCH2CH2Br in reaction with a platinum compound, so I need to know which is more electron withdrowing the phenyl ring or Br?if this molecule attacks to a platinum compound which C is more active?Does any body know about its organic properties?which organic books can help me about it?

    many thanks,best regards

  • A.K. Keshari added an answer in Fluid Flow:
    What is the best characteristic length to calculate Reynolds number?

    What is the best characteristic length to calculate Reynolds number downstream of the block at the red point (as is shown in the schematic)

    A.K. Keshari · Indian Institute of Technology Delhi

    Reynolds number should represent the flow condition. For pipe flow, the characteristic length is taken as D (diameter of pipe). For the free surface flow like channel flow, it is taken as hydraulic depth (R = A/P; A being flow depth and P being wetted perimeter). Thus, for free surface flow in a circular pipe, it is D/4 and y (water depth) for wide rectangular channel. It is not clear from the diagram whether cross-section is circular or rectangular. It seems the flow is channel flow and I guess it is having rectangular cross-section. Thus, you can calculate R for this which will be function of flow depth over the obstacle and obstacle width. 

  • When and where do we use the term drought and water deficit stress?

    Quite often it is said that if we write studies to understand the drought tolerance of coconut or some other crop it is not correct. Please clarify this.

    Heshmat Soliman Aldesuquy · Mansoura University

    Drought can be defined as the absence of adequate moisture necessary for a plant to grow normally and complete its life cycle. Drought is intensively documented to alter almost all metabolic pathways occurring in the plant cells, and thus it can modify plant morphological, ultrastructural, physiological, biochemical and molecular features (Demirevska et al., 2008). The response of plants to drought stress varies greatly depending on the intensity and duration of stress, genetic makeup of plant species and its stage of growth (Parameshwarappa and Salimath, 2008).

    The pattern of water use is crucial for plants grown with a limited amount of water in soil profile because the plant success depends largely on a sustained water use (Kato et al., 2008; Aldesuquy et al., 2014a). However, plants are developmentally and physiologically designed by evolution to reduce water use under drought stress (Blum, 2005). Therefore, the study of water use efficiency (WUE), defined as the ratio of dry matter production to water use, is particularly interesting in situations where growth is affected as a result of limiting water availability (Anyia and Herzog, 2004). The effect of drought on WUE has been investigated in different plant species such as Zea mays (Ashraf et al., 2007).

    Leaf relative water content (RWC) is proposed as a more important indicator of water status than other water potential parameters under drought conditions, as it is believed that RWC is a reliable parameter for quantifying the plant-drought response (Rahbarian et al., 2011). During plant development, water deficiency significantly reduces RWC (Siddique et al., 2000). A decrease in RWC in response to water deficit had been reported in several studies (Aranjuelo et al., 2011; Farshadfar et al., 2012; Hasheminasab et al., 2012). As a practical proof, Shinde et al. (2010) observed that drought considerably reduced RWC in four groundnut varieties. Additionally, water-stressed wheat and rice plants had lower relative water content than non-stressed ones (Farooq et al., 2009). 

  • Radiation damages during EBSD investigation in SiO2 (agate)?

    Did anybody investigated agate and observed radiation damages caused by electrons?

    Attached is one image which displays a forescattered elevtron image. It displays clearly orientation contrast in quartz (big grains) as well as in the fine-grained agate. If I try to scan the agate in EBSD mode, (dwell time in the scale of 20-30ms) the structure obviously collapse the the electron beam interaction. A strong topography change appears always there where agate is assumed. A reduction to 10keV electrons does not help.

    A similar effect I observed at small-grained calcite at a contact zone. Patterns are locally detectable, but only once. Then a clear topography change become visible comparable to agate. Investigating calcite in bigger grain (highly twinned and a few 100µm away) this effect does not appear at all.

    Hamida Mohammed Bakr Darwish · King Abdulaziz University

    Hi  Gert

    Should be the beam of electrons does not carry  enough energy  to ionize the sample. So the radiation  of electron should has sufficient energy only for excitation and the movement of an electron to a higher energy state. but if the electron has a higher frequency and shorter wave length than nonionizing radiation and long time of exposure it can burn the sample. These can attributed the answer for Prof Oğurtani   that your sample is rough and not flat enough and therefore the top of the roughness  area of the sample  will be near the beam  of which make some of the sample  burned and damaged and the irradiation with high voltage can caused color changes also. otherwise there is another interpretation for this feature It has been found experimentally  that the exposure to higher the energy of radiation decrease the melting point  of the sample and can escaped   toward the lower  temperature area  and  changed the color. If we have a look to your micrograph it looks like the material moved toward the edge.

    So from my opinion before the experiment there are some requirement have to do first
    1) You have to polish the sample very well.
    2) Also you can do long scan (I.e. the exposure time must be very slowly may it takes hours why not) but you have to decrease the kV.
    May this can help

    Good luck

  • Chitea Florina added an answer in Geology:
    Which geophysical methods or combination of methods can be most appropriate for detecting fractures/fault in a rock formation?

    Hi, I have a course work where I should suggest geophysical methods for the investigation for the construction of the rock tunnel. I know the location of the tectonic zone and I need to investigate soil conditions and bedrock quality.
    Unfortunately I have no previous experience with geology. Hence, would like to get some suggestions, please.
    Tunnel depth will be between 30 and 100 m below the ground. It is known that soil depth is 3 - 10 m and it mainly consists of till, sometimes covered by peat. Minor areas consist of sand and gravel. Gneiss is dominating rock type and it can be cut by amphibolite dykes.

    Chitea Florina · University of Bucharest

    Fractures are different than faults, so the approach (in my opinion) should be different. I associate faults with “jumps” or movements of the affected layers. If this is your case, the first method to be applied is gravimetry. But for sure there is a Bouguer Map of the area, so check first the existing data. Next best option is Seismic.

    Keep in mind, that fractures& faults can modify the porosity & permeability of affected geological formations. Due to this effect, also electrical resistivity or electromagnetic methods can be applied for the top part.

    You should also analyze the groundwater resources!

  • Gopinath. R. added an answer in AMOS:
    There is a relationship between measurement model and path model in AMOS analysis. Which model picture is essential for final Ph.D. Thesis Report?

    There is a relationship between measurement model and path model in AMOS analysis.

    Gopinath. R. · Bharathidasan University

    Dear Dr.Subhash C. Kundu, sir,

    Which one model is essential and enough for Ph.D. thesis report Please.

  • Martin Williams asked a question in Freezing:
    Cryoprotectants, with to use and in wich % ?

    Hello, i want to know wich cryoprotectant is the best and in with % to freeze:

    • Bacteria at -70
    • Eucariotic cells in liquid nitrogen

    And besides that, Is there any protocol to freeze bacteria at -20 ºC? Wich cryoprotectant should i use and in with % ?

    Many thanks!

  • Arezou Nayebi asked a question in VHDL:
    What are the programming syntaxes in VHDL to find maximum and minimum of signals in an array ?

    For example I want to generate 64 8-bit samples in an array then I want to compare every 8 , 16, and then 32 samples to find the minimum and maximum of the chosen packet. 

  • Pooria Moozarm Nia asked a question in Polypyrrole:
    How can I dissolve electrodeposited polypyrrole?

    I use electrochemical polymerization for synthesizing polypyrrole. The main problem for electrodeposition of polypyrrole is that the deposited film does not solve in any way.  I need it to be solved in a solvent in order to obtain TEM or other tests. And also how can I prepare free film of polypyrrole through electrodeposition process?

  • Why does statistics on FDI stocks have negative values?

    I collected data on bilateral FDI from OECDstat http://stats.oecd.org/Index.aspx?DatasetCode=FDI_FLOW_PARTNER

    Many data on FDI positions (stocks) are negative. Can anyone explain this for me?.

    Thank you very much!

    Anh Nguyen · University of Warsaw

    Im talking about fdi STOCK, not fdi net flow :(

  • Mark Farman added an answer in Microarray:
    What is the best way to compare bisulfite seq data and microarray data for cell lines treated 5-aza?

    So, here's the data I have:

    Microarrays showing DEGs from cell populations treated with 5-aza and untreated cell lines. Bisulfite seq data for the same cell lines with the same treatments.

    My question is: How can I compare/associate methylation +/- 200 bp from start of transcription in DEGs with changes in expression on a genome wide scale without having to look (at least initially) at individual genes at the sequence level? Are there any good programs/approaches for analyzing this type of association on a genome wide scale?

    Ideally, I'd like to identify genes that exhibit both >50% reduction in methylation about the start of transcription, and a greater than 3-fold increase in expression. Doing this for the microarray is fairly straightforward, but pulling all the corresponding sequences individually from the bisulfite data is a daunting task involving thousands of loci. There must be a better way. Is there a better way?

    Mark Farman · University of Kentucky

    Yes, definitely. Continue to grow the cells for as long as is experimentally and scientifically feasible.  Make sure you assess cell growth, so you can estimate the number of doublings.  Most importantly, however, when you do the expression analysis, you should simultaneously analyze the same cell populations using bisulfite sequencing to ensure that the desired alterations in methylation did in fact occur.  Otherwise, you might find that a subclass of 5-aza resistant cells are what continue to grow in the plate, while the cells that are actually inhibited could be arrested.

  • V. T. Toth added an answer in Particle Physics:
    No experiment directly observed Quark particle, why do we think Standard Model is a valid theory?

    The Standard Model of particle physics is a theory concerning electromagnetic, weak, and strong nuclear interactions, which mediate the dynamics of known subatomic particles. The current formulation was finalized based on the existence of quarks. There is no way to proof the existence of quark. It is pretty risky to build a theory one something that may not exist. It neither explains force hierarchy nor predicts the structure of the universe. The Standard Model falls short of being a complete theory of fundamental fields. Mathematically, the standard model is a quantized Yang-Mills theory. Because of its success in explaining a wide variety of experimental results, the Standard Model is sometimes regarded as a "theory of almost everything".

    V. T. Toth · N/A

    I'd like to take argument with the assumption stated in the question, as I believe it reveals some confusion regarding what it means to observe a quark.

    It is true that no free quarks can exist in the Standard Model. However, it does not preclude us from observing confined quarks inside hadrons in high energy experiments.

    The principle of these experiments is no different from the seminal experiments by Rutherford that led to his famous "tissue paper" comment: by firing high energy particles at a proton, for instance, and observing how they scatter, we study the proton's internal structure. Just as Rutherford inferred the existence of a small atomic nucleus from scattering experiments, we infer the existence of quarks inside hadrons the same way. These observations are just as "direct", insofar as observations go, as inferring the existence of the Moon by studying photons reflected and scattered by it amounts to a "direct" observation.

  • Dejenie A. Lakew added an answer in Mathematics:
    Why are mathematically most accurate conclusions?

    Here I mean the mathematics of the 20th century and the 21st century.

    Dejenie A. Lakew · John Tyler Community College

    The truth of things are their most accurate behaviors of natural phenomena in which nature expresses itself. These behaviors can only be logically deduced and explained through mathematics which makes mathematical understanding of things as the best and most closer understanding with most accurate conclusions at a particular timespace.    

  • Rekha Saraswat asked a question in Networking:
    Please help me to choose the best simulator among NETSim, QualNet and OPNet for conducting  experiments by the students in networking lab.?

    I need the tool for simulating the networking concepts in lab for students/by the students, so that they can understand the things well.

  • Arnold Trehub added an answer in Cognitive Systems:
    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.

    Arnold Trehub · University of Massachusetts Amherst

    Marc: "... every organism has its own subjectivity when it has to interact with its environment or to feel its own body (when it has the capacity to). 

    Let's be clear. You are claiming that any reflexive sensory-motor response of an organism is an example of subjectivity. Am I right?

  • Thaddeus Carvajal added an answer in Bacterial DNA:
    Do you know the Proteinase K Protocol?

    We have extracted bacterial DNA throughout boiling procedure. We want to purify

    extracted DNA by proteinase K.

    Denaturation and sedimentation of residued proteins is the goal.

    Thaddeus Carvajal · Ehime University

     Hi Payam, this is very interesting and we have never done this in our lab. Probably if you have extra samples, you can optimize it by differing number of PK and incubation period. However, just like in QIAGEN, you will need a filtering system to really get pure DNA. Or if you can, try to look at the DNA quality thru nanodrop before and after PK. Please let me know what happens. I will try to ask my colleagues on this matter also. 

  • Go J Yoshida added an answer in Cancer Stem Cells:
    Any suggestions about Laminin - as a chemo-attractant in cultivating cancer stem cells?

    Hello, has any of you done some research on laminin being as a chemo-attractive protein in cultivating cancer stem cells? Could you share your experience about the work you've done?:)

    We are struggling to find the optimum concentration and incubation time of laminin-based-coating and I could really use some advice from more experienced people at this field. We are cultivating the cells in already-coated flasks, but,additionally, we add a coating of poly-L-lysine (1:10) and laminin (1:100), but the cells seem to adhere unevenly and differently.

    Thank you for replies!

    Go J Yoshida · Tokyo Medical and Dental University

    It has been shown that cancer cells show the deposition of laminin gamma-2 chain when they undergo EMT process, in which the number of CSCs dramatically increases. Indeed, 3D culture system using laminin leads to the increased expression of "functional cancer stem cell markers" such as EpCAM and CD44 variant.   

  • Chitra Ravi asked a question in Eyes:
    Which classifier and feature extraction techniques for gender recognition?

    i extracted the features of left eye corner and right eye corner and also nose center point. now i want to crop that region from face and have to classify gender using the extracted region values. which classifier and feature extraction techniques used for gender detection

  • Lester Lipsky asked a question in Correction:
    The scondauthor is NOT Kevin Smith, but Kenneth Smith!

    Please correct the A\author's name.

  • Keerti Potluri added an answer in SNP Analysis:
    Does Software exist that gives SNPs list in two different population?

    Hi all, is there any statistical software that gives SNPs list separately in 2 different population?? May be by putting one population as base and comparing the other population with this base And give SNPs list unique in this population but not the base.

    Thanks in advance.

    Keerti Potluri · Wright State University

    Hi Juan,

    Yes that is what i am looking for. Thank you. And so we need vcf format files for using this tool?

  • Paul M.W. Hackett added an answer in Philosophy:
    Is it possible to provide a simple definition of Aristotle's concept of powers?
    How does this relate to causation in his work?
    Paul M.W. Hackett · Emerson College

    I think your reading of individual power is very different to Aristotle's metaphysical powers.

  • Do you think that people often reveal or use research on phenomena without truly understanding all the details of the underlying mechanisms involved?

    How often results or treatments are published or used before all underlying mechanisms are truly understood?


    Medicine may treat visible signs of symptoms without understanding underlying causes of the symptoms?

  • Marek Turcani added an answer in Butterflies:
    Do we have Monarch Butterflies in Africa? Can we domesticate them any where in the tropics to study their migratory behaviours?

    During Migration, it is believed that four generations of Monarch Butterflies take last. Monarch butterflies are pretty bright and sharp orange and black coloured.

    They will make a nice tourist attraction anywhere they are domesticated

    Marek Turcani · Czech University of Life Sciences Prague

    Hi Aline,

    Monarch butterfly is (as I know) Danaus plexippus. Do You mean this species? Or also African Monarch (Danaus chrysippus)?. Monarch is, I guess, rare in Africa - recorded mainly outside of continental Africa (Macaronesia). Records from the north-west cost are known as well. D. chrysippus is more common and it lives (as several subspecies) accroos Africa. Other species of Milkweed butterflies (Danaidae) should be more common in tropical Africa (however, this is only my personal opinion:-).

    I think, it is not necessary to introduce butterfly species to the tropics:-) Better should be to use (show) local species - which might be also attractive to tourism:-)


  • Paul M.W. Hackett added an answer in Society:
    Are you optimists or pessimists for the future of humanity?
    There are many readings for the same set of data for our evolution as human beings. Others read the circular growth and recession times by a pessimistic mood while others believe that humanity after having tried different systems finally will converge to a stable and viable status for all of us and not for a small subset of us.
    What do you think about?
    Paul M.W. Hackett · Emerson College

    Pessimism seems to me to be rather like nihilism: both ring true but take us nowhere. It is not exactly a useful doctrine to believe that there is little meaning to anything and that most things are negative. However, to believe anything else is irrational. 

  • Can I use a logistical regression for this type of problem?

    I want to test whether better off people are more likely to receive a specific good (=good X) than less well off people. Thus, my independent variable (wealth, measured in US$) is continuous. My independent variable (did they receive good X: yes/no) is dichtomous.

    Is the logisitical regression the best test for this? 

    And if so, do I interpret the results correctly? I interprete them as follows:

    Prob > chi2 = 0.0001: thus, one of my variables (or in my case, my one and only variable) does contribute to explaining the dependent variable.

    P>|z|=0.000: thus, wealth does contribute to explaining the likelihood of benefitting (or not)

    HOWEVER: Pseudo R2 = 0.0091: thus, my model fits very poorly, and I have left out lots and lots of other explanatory variables

    And also, running a "fitstat" on Stata resulted in an Adj Count R2: -0.004. Thus, using the independent variable wealth only leads to a 0,4% improved prediction of whether people receive good X than not attempting to explain anything using the variable wealth. 

    Thus, if all of the assumptions of a logistic regression are met, in conclusion, one can say that a person's wealth does NOT have an influence on whether or not they will receive good X. Is this right?!??

    And second question: is there a better test I could use for this? 

    Thanks so much for any help!!


  • Heba Mohamed asked a question in Risk:
    Hi, does anyone know if E-views 8 do panel VAR or not because I keep getting different answers?

    I got the following:

    1-Credit Risk

    2-Market Risk


    4-Loan Growth rate

    5-GDP growth rate


    7-Efficiency Ratio

    8-Total Assets

    9-Return on Assets

    I want to see if Credit and market risk affect each other not 

  • Gamal Seedahmed added an answer in Development:
    Are information technologies a key catalyst to success and development of non-developed countries?
    We are more than ever trying to convince the young that professions dealing with IT technologies are not just for genius people, but for everyone. Right after they graduate, there is a prospect of finding jobs with monthly wages well over the average in Serbia. All they need is to be hardworking and ready to learn and move forward. IT technologies are a great way for the developing countries to advance, promote and use for the benefit of everyone. All that is needed for taking "IT steps" is: a few computers, a little space and a lot of "brain" space. What are your experiences of this?
    Gamal Seedahmed · University of Khartoum

    Yes, with no doubt IT is a key driver for development in non-developing countries. But we have to qualify this statement by this one "If there is there is will & determination to use it to develop the economy of this particular country". For IT to flourish in any place, it should be connected with a true economy and with a true productivity. IT should be part of the economical cycle of the particular country. This is could be realized by two ways. IT products that are developed by a particular country are good enough to compete in the international market and they are a source of income of hard currency. Or IT products are part of an internal economical activity/s, which are connected with the international economy. In other words, IT as a standalone service industry in particular country could be a burden rather than a bless.

  • What kind of internationalisation strategy does your university pursue?

    In my PhD thesis I identified the most commonly employed implementation strategies with regard to internationalisation efforts. It was found that most HEI use either add-on, infusion and transformative approaches.

    While the first approach is market-driven with a clear aim to enhance transparency and reputation, the second one is an across-the-curriculum approach that seeks to implement some elements of international education; it also goes hand in hand with a mission statement of the school. The last approach is a genuine wish to educate internationally minded students that become global citizens. I wonder how these approaches look like around the world and whether there are also other strategies. Thanks for your contributions.