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  • António Maximiano Fernandes added an answer in Dysuria:
    What are the possible causes for obtaining zero bacterial growth in a urine culture?

    With a high clinical suspicion of pyelonephritis (costa-vertebral pain, fever, chills, dysuria), a urinalysis and urine cultures are obtained, in addition to other diagnostic test. The urinalysis is positive for macro-hematuria, and protein, but negative nitrates. The urine culture showed absolutely no growth. What could the potential reasons for the non-growth be? Can a delay in transport, inadequate storage, or inadequate temperature cause this? Or is there some other explanation? 

    António Maximiano Fernandes

    I really agree with Rajinder. Gram stain is a simple test we can see bacteria in urine

  • Carmen Wrede added an answer in Philosophy of Social Science:
    Praxis versus academic noises?

    Karl Marx states in "Theses on Feuerbach" that "The philosophers have only interpreted the world in various ways; the point, however, is to change it." (Thesis Eleven) I must admit that I'm all the more persuaded by that statement as time goes by. When was the last time you heard voices of conviction and righteousness oozed out from academia and how often do you see an academician get his/her hands dirty?

    If you want to get you hands dirty, here's a link:


    Hm, I guess this post so far has not been qualified as a question. So let me ask this: what do you think of Marx's Thesis Eleven in "Theses on Feuerbach"?

    Carmen Wrede

    Now come on, Mr. Downvoter *kicking a chair* Just do it!


  • Dominique Liger added an answer in Plasmids:
    Hello there, i am doing plasmid restriction digestion to linearize my plasmid for riboprobe synthesis?

    however, my plasmid is hardly visible under AGE after linearized plasmid purification step. I'm using Qiaquick gel extraction kit but it seems to make my plasmid lost a lot during purification. initially, my plasmid intensity was high in AGE band before purifying. do i need to resort to conventional method for purifying my plasmid? do it give better yield? but I also read that this conventional method may not be reliable for downstream application later. and lastly, do precipitation step with sodium acetate is good for plasmid purification or is it optional? please help me.

    Dominique Liger

    Hi there,

    If digestion purpose is only about plasmid linearization (single site digest), gel extraction is not necessary : on-column purification is enough to get pure DNA and yield will be much better.

  • Victor Aguilar asked a question in Word:
    Why is "congruent" but never "equal" used in geometry?

    I use these definitions:

    Equal               Magnitudes that are neither less than nor greater than each other

    Magnitudes are lengths of segments, radii of circles, measures of angles and areas of triangles.

    Congruent     Complicated figures with several characteristics and those that fully define the figures are equal, so we know they all are

    But my survey of extant geometry books indicates that the authors simply never use the word "equal" but have replaced it wholesale with the word "congruent."  This procedure could only be justified if there is something fundamentally different about geometric magnitudes than elsewhere in mathematics.  But what?  Those same textbooks routinely use numbers to measure lengths in meters and angles in degrees, and do so in the same way that physicists and others use numbers.  So why the different terminology for when lengths and angles are the same?

    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: I propose to write a textbook on the subject of Euclidean geometry. It will be divided into two volumes, Geometry without Multiplication and Geometry with Multiplication. In the future I may write a third volume about solid geometry. Geometry without Multiplication ranks high school geometry students as follows: White Belt: Abstract Algebra Orange Belt: Triangle Congruence Green Belt: Quadrilaterals Red Belt: Quadrature Black Belt: Circles I have written the text for white- and orange-belt students and I have written an outline of the remaining textbook. I will update as I progress. I hope to receive comments on my proofs and on my organization of theorems from other geometers during the writing of this book. Why the martial arts analogy? We are under attack from the math haters. Asad Zaman writes: “It is a completely mistaken idea that scientific theory is based on deductions from a series of postulates – that is the description of the methodology of mathematics… There is no science which uses axioms and logical deductions to derive scientific theory. “Mathematics is not a ‘science’ since it is not based in any direct way on observational evidence. Unlike scientific laws, mathematical laws are not affirmed observational evidence. Recognition of the possibility that there are bodies of knowledge which are not science would lead to greater tolerance and pluralism which is currently desperately needed.” Tolerance? No. Such outrageous talk by the World Economics Association has brought war and discord to our once quiet study of triangles. If Asad Zaman were just some crazy man, it would not matter. But Zaman is the editor of the Real World Economics Review. He wields this terrifying power to no other end than to ban all mention of deductive logic. I alone stand in his path. If I falter, then geometry will be excluded from the high school curriculum and a whole generation will be taught only hate for deductive logic. Can you help me fight the Islamic extremists? Intimidating their enemies by cutting off heads and baffling them by slyly redefining dialectical materialism as “ontology” and historical materialism as “processual,” the Islamists and the Marxists have united to rid the world of geometry and to raise a generation of Westerners with only hate for deductive logic. Logic alone can defeat the haters!
      Full-text · Article · Jan 2016
  • Jerry Rhee added an answer in Human Science:
    What should a humanistic science education mean?

    What is the best that has been thought and said about humanism, science and education?

    Jerry Rhee

    Thanks for that, George,

    What you say sounds very common sense and reflects some good aspects of complete theories.

    Since we’re trying to get at the best of a humanistic science education, would you mind offering some leaders who have influenced your view so we can reflect on its potential weaknesses, please?

  • Lotfi Zeghadnia added an answer in Special Functions:
    How to compute Lambert Function (W)?

    Lambert function has been proposed by Jean-Henri Lambert, some times called Omegat function (W).

    the equation can be written as following:

     xexp(x) = z  this means that x= W0(z)

    So the question is , how can I compute W0?

    Lotfi Zeghadnia

    Dear Ken Roberts:

    Thank you very much forthe  care of the question. Your paper present a great idea, i'll try to benifit from it. thank you again.

  • Sobhan San Mohammadi added an answer in Heat Treatment:
    How to tailor magnetic texture of Ni-Fe alloys?

    Hi, does anyone have exact Methods to tailor the texture of 50Ni-50Fe alloys, to get the best possible magnetic properties?

    I know a little that it is possible to engineer the texture by Alloying elements and heat treatments, but how exactly?
    Your input is highly appreciated.

    Sobhan San Mohammadi

    Dear Dr. Radovan Bures
    thank you for your answer. You are absolutely right, i should've mentioned that it is sheet, and casting process is carried out in a vacuum induction furnace.
    When you mentioned that " Mo is grain grow suppresor e.g. Si create nano-crystalline phase which induce domain wall pinning," these effects are related to powder particles right? can i use this for my research?
    my goal, here, is to get a final sheet with a low coercivity and high  permeability. in doing so, i need your help, if you can recommend me a reference or any input to understand the effect of alloying elements and relevant heat treatments on domain structure of 50Ni-50Fe.


  • Fatma-Elzahraa Eid asked a question in Illumina:
    Is the allele phase maintained in SNP data output by affymetrix and illumina?

    Examining a data file reporting the SNPs for each individual using some illumina chip, each SNP position has two values for each allele. For SNPs S1 and S2, the first alleles have values v1 and v2, and the second alleles have values v3 and v4. Must v1 and v2 really lie on the same allele, or the order is not maintained?

  • Anton Schober added an answer in Quantum Mechanics:
    Show that linear momentum is not quantised?

    quantum mechanics

    Anton Schober

    same with not perfectly relecting walls.

  • Amy Zhu asked a question in Ligation:
    Have you ever had the same experience of a puzzling targeting vector?

    I'm making a targeting vector now to make a knocking mouse, after I ligated my fragment(gene of interest) into the vector, I found one of the stop element between the Loxp sites was missing when I sequencing the plasmid. The original plasmid have three stop elements(SV40_PA) between the two Loxp sites, while after my ligation, there's are only two left. My question is how this happened? and is this plasmid still working for making my knockin mouse? Thank you very much.

  • Gerges Youssef added an answer in Structure Analysis:
    I am trying to perform structural analysis of a viscoelastic plate using ANSYS Transient Structural Solver. How can I model the damping properties?

    The plate is excited at the base, plunging motion. 

    Gerges Youssef

    I used a software called ViscoData to compute the Prony Series Coefficients. I entered this set of data to Prony Shear (in the Viscoelastic section).
    The procedure I followed resulted in getting accurate results.

  • Erkki J. Brändas added an answer in General Relativity:
    Universe is static!!! Yes or no?

    Space of Universe is static! Yes or no?

    Question: Are there any observations that do not fit into the model static space of Universe, are there any theoretical obstacles to the existence of such a model?

    I assume that the Universe is eternal, infinite and static, it is not expanded and not curved, it is possible to construct a preferred inertial frame of reference in which the CMBR is most isotropic. The matter in this space evolves, but the average density of matter and energy (in large enough volumes) fluctuate within a rather broad range.
    The light in this model is "tired", the speed of light depends on the optical density intergalactic medium. Gravity is also "tired" t.i. weakens a little faster R2. The energy of destroying matter goes into the surrounding vacuum. The excess energy from the vacuum give rise to new particles of matter.

    I state that all the observed cosmological effects can be explained in such a Static Model of the Universe.
    See attached "Basic_Cosmological_Formula_1_En.pdf"

    Dear colleagues, I do not ask, what are the problems faced by other theories (though I would be interested in your opinion on that. The General theory of relativity is not applicable to the entire space of the Universe).

    Erkki J. Brändas

    Dear Azzam,

    Your proofs in your previous postings are wrong.

    If you are going to show that LT is invariant under scaling you need to demonstrate that scaling of the coordinates x,y,z,t by an arbitrary positive constant S you only need to show that the scaled coordinates Sx, Sy, Sx, St transforms to Sx1, Sy1, Sz1, St1, under LT. This follows trivially since the Lorentz factor (1-v2/c2)-1/2 is invariant. The same is also true for the eigentime.

    In addition the weak gravitational field approximation does not apply since the factor (1-GM/rc2)-1 is not invariant under scaling of r, i.e. r ⟶Sr.

    As I told you before in another thread, STR does only account for half the lightbending and the perihelion of Mercury. Your inclusion of QM in GR is a mistake and full of errors!

  • Clemens Glombitza added an answer in Biological:
    What is meant by the terms “selectivity” and “sensitivity” in the context of measurement of biological chemicals.

    Is it better to have one compared to the other?

  • Waldemar Koczkodaj added an answer in Fuzzy Logic:
    Do you have a case for homework assignment to solve by using FuzzyCLIPS ?

    I need a problem specification and its solution

    Waldemar Koczkodaj

    test msg was sent

  • Johanna Rafaela Ortega Briones asked a question in Source Coding:
    Compare routing protocols with energy efficient in ns2?

    I want compare routing protocols with energy efficient. I picked up around 19 routing protocols (EAR, APTEEN, LEACH-C, BCDCP, SHPER, CHIRON, A-LEACH, HEERP, U-LEACH, HSEP, GEM, GeRaF, MERR, EAGRP, LEAR, EEMRP, REER, SAR, QEMPR) but I don't have source code of this protocolos.
    Do you know where I can find the source code in ns-2 of all these? or can you help me? Thanks a lot...

  • Köksal Banoğlu added an answer in Logit:
    Is it weird to get a very big odds ratio in logistic regression?

    I estimated logit using enter method and one of the odds is of 3962.988 with sig. 0.000.

    And another model, estimated using forward stepwise (likelihood ratio), produced odds ratio of 274.744 with sig. 0.000.

    Total N is 180, missing 37. The model is fitted based on Omnibus and Hosmer & Lemeshow. 2LL is ok.

    Is there anything wrong? Please assist.

    Köksal Banoğlu

    Hello Roslina,

    I am dealing with a similar problem and I wondered whether  you found probable reasons of your problem?

  • Eranthi Chathurika added an answer in Standard Deviation:
    What are the different types of applications of variance and standard deviation?

    The standard deviation is the square root of the variance. I am confused about the meaning of variance and SD in terms of a distribution.

    Eranthi Chathurika

    Thank you Nisha Arora, and  Ilya B. Gertsbakh. Actually I was certain about the mathematical explanation of SD and variance. 

    Thanks a lot Khurshid Ahmad Bhat and Shweta Mehrotra for explain me the logical explanations of SD and variance. That is what I really needed to know. 

  • Sefakor Magdalene Fummey added an answer in Small Business:
    I am studying the role of Business Advisory Centres in the retention of micro & small businesses in Ghana. Pls suggestions of works to consult?

    Pottery is an age long occupation of the people of Vume of the Volta Region of Ghana. However, the production process, nature of work environment and medium of display or advertisement seem to suggest it is unnecessary to  expand operations which hitherto could bring in fresh capital, expertise and also creating employment opportunities within the Cluster.

    Sefakor Magdalene Fummey

    I am grateful for the wealth of information provided.

    Thank you for making time to compile and attached those documents.

  • Yasser Awad asked a question in Specialist:
    Crystalline amphetamine and its relation in creating psyhotic symptoms, i was searching for a suitable tool to match this study? any help?

    psychiatric specialist and clinical nurse specialist

  • Sofia D. Wechsler asked a question in Raising and lowering operators:
    What is the relationship between lowering (raising) operators for identical particles from different sources?

    The principle of the Hanbury-Brown and Twiss experiment (see picture) says that the joint amplitude of probability that a particle from the source A be detected in the detector 1 and a particle from the source B in the detector 2, undergoes superposition with the joint amplitude of probability that a particle from A be detected in 2, and a particle from B in 1.

    I am not sure on a couple of things when we do operatorial treatment. 

    Let âA1 , âB1 , âA2 and âB2 , represent the raising operators that create a particle of type A at the position of the detector 1, a particle of type B at the position of the detector 1, and so on.

    If I construct the two-particle field operator (see picture)

    (1) Ȃ = |pA1> âA1  |pB2> âB2 + |pB1> âB1 |pA2> âA2 

    and calculate <Ȃ Ȃ>, one of the terms will be

    (2) <pA1|<pB1| x |pB2>|pA2> <âA1 âB2 âB1 âA2> .

    where by  x  I denoted direct product.

    I suppose that âB1 commutes with âB2 because they act at different places, s.t. I may write the average in (2) as <âA1 âB1 âB2 âA2>.  But, assume now that the sources A and B are identical. May I say that the operator  âA1 âB1  is equal to the number operator n̂1 because the two particles are identical?

  • Pierlorenzo Brignoli added an answer in Orphanages:
    Who is an orphan? How do you deal / help or treat orphans in your city/ country? Do you have enough orphanages in your city/ country?

    Orphans are relatively rare in developed countries, because most children can expect both of their parents to survive their childhood. Much higher numbers of orphans exist in war-torn nations such as Afghanistan, Iraq and Syria. 

    Pierlorenzo Brignoli

    I live in northern Italy where the orphanages are sufficient although in recent months we have had many rifugees. The italian authorities have so far handled the situation well and we have not serious problems at the moment. We know that there are countries where the situation is very different. Personally I try to do my best by giving maximum support with donations to international organizations that are helping orphans in the needy countries.

    from mobile

  • Ryszard Soluch added an answer in Restriction Enzyme:
    How can I find PCR reactions using certain restrictases?

    I have some restriction enzymes (HpaII, BsmAI, Hind III, BsiI, Hin6I, MspI).
    Haw I can find all PCR reactions using this restrictases?

    Ryszard Soluch

    You could look for sequence containing restriction sites of these enzymes to find whole matching sequence. Though I do not see much sense in blindly looking for DNA to cut.

  • Manuel Herrera added an answer in Urban Environment:
    Urban climate change resilience assessment framework

    Hello!!! I would like to have your views and thoughts on what to include in a climate change resilience assessment framework for urban environments. Thank you

    Manuel Herrera

    Hi Asimina!

    Studying the effect of "summer years" and the extreme weather events associated with climate change could be a good starting point. In addition, taking into account the urban heat island effect could also improve the accuracy of your proposal. 

  • Abdallah chabane-chaouche added an answer in Quantum ESPRESSO:
    Parallel compilation of quantum-espresso

    hi every one, I am using the 5.1 version of quantum-espresso and i want to compile theme with openmpi (parallel) but i dont now hwo to do that

    I have a linux system (ubuntu 14.04 64bit) which installed in HP Z800 workstation

    any help .............? 

    Abdallah chabane-chaouche

    Dear Pradhan 

    thanks for your help. 

  • Younos Aboulnaga added an answer in Empirical Research:
    Is it even theoretically possible that we infer that a set of conditions are sufficient, using empirical methods?

    I am not in the Medical field myself, but I really admire it. However, as a person who uses stats in my job, it boggles my mind how we keep hearing that the folks doing medical studies have discovered "the gene responsible for X" or the "cause of Y". I really wonder how causation inference work in medical studies. Here is how I think about it:

    It is safe to say that we can observe sets of conditions that frequently occur along with a phenomenon (correlation), and let's now focus on preconditions only (greatly simplifying the problem). I think that for a set of conditions to cause the phenomenon, they must each be necessary for the phenomenon and, together, they must be sufficient. Now, let's see if we can infer necessity and sufficiency. Necessity means that there is not a single observation of the phenomenon where the condition was missing. So, arguably we can infer necessity, albeit being a tough job and the result must be labelled by the infamous "to the best of our knowledge". Sufficiency is the one I am struggling with. Is it even theoretically possible that we infer that a set of conditions are sufficient, using empirical methods?

    Younos Aboulnaga

    Thank you very much David [@David_Roberts56] and Alrik [Alrik_Thiem]. Such a wonderful discussion, that left me speechless with gratitude for the amount of effort you put into answering my question. It also left me with so much reading to do; not the answers, but the references. In particular I will be reading about QCA and CNA, Mill's methods of Agreement and Difference, as well as Pearl's Do(x) calculus. I will not be able to finish all this and catch up during the weekend, but I will try to read more during my daily commute to catch up. Thanks again.

  • Aparna Murthy added an answer in WDS:
    How do you understand the coexistence in Wireless Communication Systems?

    The coexistence of wireless devices (WDs) represent an important challenge. As far I understand the coexistence concept considers at least two considerations - spectrum (frequency) & coverage area- and I include other one: time. With these three 'parameters' I can describe, in wide sense, the coexistence but I do not know if my context is complete, then I would like to know your idea,

    -How do you define Coexistence of WDs?     

    -What parameter must I consider to define it?

    Your comments are important for me.


    Aparna Murthy

    I am sure , you know this :

     Device Identification - there are unique identifying signatures /IDs when devices come in a given radius say Eg: Bluetooth devices (for smaller networks)  ; 802.11 physical layer or RF (front-end) for device identification

    Co-existence - ISM band , Eg: I guess 802.11 and Bluetooth operate @ 2.4G but use different coding schemes for the transceivers can be configured as slave for establishing the communication link.

    As you have said coverage (SNR)

    Time ?? not sure because these links (especially Bluetooth you are not paying ) , 802.11 (yes - service provider will charge you !!)

    I guess this is an issue that is addressed already and that is load !! How much is the traffic and if network is clogged due to one device so that all other in the network are allowed to transmit and receive by giving fair chance...

    Signal based: clock (embedded) , differential signals , BW/baud rate

    mipi.org (has specs for RF front end)

  • Silburn Clarke added an answer in SMEs:
    What are the pros and cons of the EFQM Business Excellence Model versus the ISO model for SMEs ?

    Both the European Foundation for Quality Management and the International Standards Organisation have quality standard frameworks for enhancing the business practices of outward-looking export-oriented SMEs. Are they competing frameworks? Am interested in uncovering the pros and cons of these two frameworks? 

    Silburn Clarke

    Prof Sardana,

    The call should for forth for the development of a Global Business Excellence Model (GBEM)


  • Dominique Liger added an answer in Yeast Transformation:
    What is the probability of getting revertants after yeast transformation?

    Hi, I am working with a yeast strain which is knockout for a gene of interest (AMP Deaminase) (gene replaced by g418 casette). this strain cannot grow on S-adenosyl methionine (SAM). I transformed this yeast strain with a PCR product coding for the same gene from different organism so that the G418 casette is replaced by homologus recombination. I select for the transformants on minimal media plate containing SAM. i get colonies after two days. but though these colonies are growing on SAM plate when i streak on G418 plate, they grow there as well. And PCR indicates the presence of G418 casette even after transformation. If G418 casette has not been replaced why do i see growth on SAM plates. are these some mutants that are unable to take up SAM? what might be happening? the strain and the reagents have been checked multiple times and the controls are working fine. Thanks in advance

    Dominique Liger

    Hi there,

    Reversion is very unlikely as you perform gene knockout by full deletion. Therefore I think insertion of the PCR product might happen elsewhere in the genome explaining the persistence of resistance as well as the "reversion" of SAM use deficiency. PCR screens on transformants for location of G418 cassette and the presence of foreign gene would actually tell you.

  • Deborah Jean Verran added an answer in Behavior Change:
    What are existing approaches to design of behavioral interventions supported by web, mobile, and sensor technologies?

    I am very much interested in the field of behavioral intervention research where much work has been done in order to decompose interventions into behavior change techniques in order to find out what techniques do help achieve the desired behavior change. 

    I am interested in design and deployment of eHealth and mHealth solutions that are in fact behavior change interventions. For this, I would like to see, what existing frameworks exist that bring together knowledge from different sciences that is eventually used to inform the design of these solutions.

    I would also like to collect information about existing platforms that support more than one intervention.

    Thank you!

    Deborah Jean Verran

    You may be interested in this online report via NHS Blood and Transplant in the UK outlining their approach to for achieving community engagement via social media on organ donation-


    This is supported by evidence accumulated via online registrations and came about via insights gained from behavioural economics.