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  • Wes Raikowski added an answer in Ontology:
    What are infinitesimals------- a 2500-year suspended problem?

    The newly discovered modern Harmonic Series Paradox is one of family members of ancient Zeno’s Paradox, it discloses relentlessly a fact that we human still don’t know what infinitesimals are: are they with or without numerical meanings, zeros?

    Infinitesimals are there in our science, but what are their positions as numbers or non-numbers or something else theoretically and operationally, ontologically and formally?

    This problem has close relationship with whole fundamental part of infinite related area in our science:
    1, theoretical and practical infinite theory
    2, theoretical and practical limit theory
    3, theoretical and practical infinite related number theory

    Wes Raikowski · Griffith University

    Hi Ellis,

    Re: So, is there a mathematically rigorous statement of a problem in this thread, or not?

    This is my problem too. So far I have not seen one. The author postulates a number of new terms to solve problems which seems to be more apparent than real:

    “Three new infinite related number forms were discovered: (inter-small, indistinct-small), (inter-great, indistinct-great) , (yan). And a new number spectrum was constructed: 0(zero), (infinitesimal), (inter-small, indistinct-small), (finite-number, distinct-number), (inter-great, indistinct-great) , (infinity) , (yan).”

    (by Geng Quhang, “ A Revolution in the “Infinite” Related Foundation of Mathematics...”)

    Neither conceptual nor mathematical basis for the claims is given which makes it difficult for anyone to take stand regarding the proposal. It is not a critique of the theory itself, but its vagueness. To create new terms without telling how they relate to each other and what they have in common is not enough. I need more. 

    Regards to all, Wes

  • Sajjad Nazidizaji added an answer in Prediction:
    How can someone predict the performance of a contractor?

    Can someone really predict the performance of candidate contractors during the precontract stage? How will you do this?

    Sajjad Nazidizaji · Technical University of Lisbon

    Dear Dr Oluwole Alfred Olatunji

    I am not sure that I understood your question well , I think it depends on the size of contractor company , if it is about contractor for big projects , I think the grade of company , well reputation of company in previous projects, quality certificates ,.. can be enough , but about subcontractors the situation is a little bit complicated ,  I think about subcontractor we may ask them to do a very small sample work in our project then we may evaluate their quality of work

  • Rahul Roy added an answer in Spirogyra:
    What is the role of Hemicellulose in spyrogyra?

    Can someone shed some light on the role of hemicellulose in spirogyra ? What kind of hemicellulose is that? Are there any experimental studies available on co-valent/non-covalent interactions between this hemicellulose and cellulose in spirogyra?

    Thanks for your time.

    Rahul Roy · Iowa State University

    Hey, I am not an expert but i found this paper and they think that the xyloglucan helps in cell cell attachment in Spirogyra. Best of luck in finding out more.


  • What is the major problem of the authentication protocols in Wireless sensor networks? To what extent we can improve on them?

    I'm an MSc student conducting an academic research on how to optimise authentication protocol in wireless sensor network. My concern is to know and recognize the best protocol I can select to narrow my work into one single protocol. This is challenging for me to critically understand on the most appropriate and suitable protocol I can choose to improve on my research work.

  • Yuan-Yeu Yau added an answer in Primer:
    Are Mops fx/fx primers especially finicky?

    I'm a tech who's still getting the hang of running PCR. I've been doing it for about 6 months with three different genes (mop3fx, cre, and per2luciferase) and I've noticed that my mop3 primers very rarely give good results. I've been getting very faint bands, or no bands at all, and when I use the same DNA with a different gene I get great bands. I've ordered and re-ordered the primers twice so far. I have a working stock of 10uM and multiple small aliquots to minimize freeze-thawing. Is there maybe some rookie mistake I'm still making?

    Here's the sequences for my primers




    Any tips or advice would be much appreciated.

    Yuan-Yeu Yau · Northeastern State University

    Yes, and please do let us know the results.

    Good luck.

  • Shian-Loong Bernard Lew added an answer in Urbanism:
    Is there a certain optimal geometry to the kind of urban agglomeration that we see in the world?

    Scientists have come to observe that the hexagon is the optimal geometric shape for packing within limited spaces. Has there been work done in a likewise manner on urban agglomeration?

    Shian-Loong Bernard Lew · Taylor's University

    Dear Vanessa,

    Indeed the problems with urban form are governance-related and institutional as well. It would be interesting to know how planners have incorporated historical understanding and more formal approaches in their assessments of urbanism.

  • Alex Ravsky added an answer in Number Theory:
    Is there any possibility for the sumset of two sets of integers, which are not arithmetic progressions, to be an arithmetic progression?

    The notion of sumset of two sets is defined as A+B={a+b:a in A, b in B}. If the elements of A and B are not in AP,  then can the elements of A+B be an arithmetic progression? If so, what are the conditions required for that? Please suggest me some good references...

    Thanking you in advance,

    Sudev Naduvath

    Alex Ravsky · Pidstryhach Institute for Applied Problems of Mechanics and Mathematics

    It seems the following.

    The answer is positive. Let n>= 4$ be any natural number, A be the set of all n-digits binary numbers which have 1’s only at the odd indices (for instance, for n=4, A={0000, 0001, 0100, 0101) and B be the set of all n-digits binary numbers which have 1’s only at the even indices (for instance, for n=4, B={0000, 0010, 1000, 1010). Then both A and B are not arithmetic progressions, but A+B={0,1,...,2^n} is an arithmetic progression.

  • Kristin Biris added an answer in Freezing:
    Can anyone suggest me a protocol for snap freezing of mouse stomach/intestine?

    I am interested to look at the histology of mice stomach and intestine. We always do snap freezing of other tissues but have not done on stomach. Can anyone suggest me a protocol for snap freezing? Thanks

  • Ehsan Mohseni added an answer in Abaqus:
    Is it possible to create a multi-turn coil in Abaqus?

    I have not work with Abaqus for a while and I know some electromagnetic features of software are improved recently, I would like to know if there is any possibility  to generate a multiturn coil in abaqus without the need to create each turn separately. I mean is  there any feature or module for this purpose? I really appreciate any help on that.



    Ehsan Mohseni · École de Technologie Supérieure

    Hi Saeed,

    I am hardly trying to avoid creating a spring coil regardless of CAD software, I am wondering if it could be possible to create a simple hollow cylinder in Abaqus and assign coil turns and wire cross section to it.



  • Rahul Roy added an answer in Leaf:
    How can determine the characteristics length of plant leaf?

    I need to estimate the characteristics length of the plant, 

    there have any straight forward methods, not too complicated

    Rahul Roy · Iowa State University

    I would take parameters like length of the petiole, length from base to apex and maximum width with a  ruler.

    You can also try and putting the leaf on a graph paper and outlining with a pencil and then use the markings on graph paper for a much finer measurement.

    Hope that helps. Best of luck. Also make sure that if you are comparing leaves of two different genotypes etc, they should be of same developmental age. 

  • Is the concept of a point-particle compatible with current theories of quantum gravity?

    In the Standard Model leptons and quarks are pointlike with no internal structure. The properties of these particles are then simply labels attached to points. I want to know if such a view of particles is compatible with any quantum gravity theories, in particular loop quantum gravity. In loop quantum gravity the area and volume operators have discrete spectra. Does this imply particles can no longer be considered pointlike?

    In string theory a point particle is replaced by a one dimensional string. Ahluwalia [1] has argued that the notion of a point-particle is no longer viable in a stabilized form of the combination of the Poincare and Heisenberg algebras because the resulting algebra features a modified Heisenberg sector.

    Are there any reasonable approaches to quantum gravity that are consistent with the notion of point-particles?

    [1] Ahluwalia-Khalilova, D. V. "Minimal spatio-temporal extent of events, neutrinos, and the cosmological constant problem." International Journal of Modern Physics D 14.12 (2005): 2151-2165.

    Mohamed El Naschie · Alexandria University Alexanderia Egypt

    agree with maxime. i hop he take some time and look at E-infinity spacetime theory and the Ord- Nottale -El Naschie theory

  • Yuan-Yeu Yau added an answer in Immunofluorescence:
    In the case of detecting the presence of a protein in cells, which is the best method?

    Measuring the mRNA expression using PCR, or immunofluorescence method by targeting the protein itself on the cells? What is your preference?

    Yuan-Yeu Yau · Northeastern State University

    I will prefer the use of (1) Western Blotting + (2) the measurement of the functionality of the specific protein (for example, the enzyme activity of the specific protein etc.) to verify the presence of a specific protein

  • Vivek Kempraj added an answer in Morus:
    How the silkmoth Bombyx mori went on to select mulberry, Morus spp as its host ?

    We know that the silkmoth B. mori feeds on mulberry which is its host, however, it is highly unknown why silkmoth chose mulberry? What is the reason behind choosing mulberry as its host? In evolutionary time there were many plants that the silkmoth could have used as its host, but why specifically mulberry.

    Why has it turned monophagous for mulberry? I would like to know the evolutionary reason behind this choice !!

    I have been working about this from the past 1 year although i have got some idea, i am not finding literature that supports my results! Please help

    Vivek Kempraj · National Fellow Lab, Indian Institute of Horticultural Research

    Thank you for the keen interest in knowing the answer to my question  Dr. Azevedo, however, we have published a paper in Scientific Reports recently regarding the same. It is our initial step to answer this question. We are still working on this aspect. As of now, I do not have a clear answer.


    Vivek Kempraj

  • Matúš Dubecký added an answer in Sulfonic Acids:
    What about Sulfated Graphene ??

    I want to prepare sulfated-graphene but i can't ...

    I want simple methode without fuming sulfonic acid if it is possible , please ?

  • How is it possible to develope uncured photoresist placed inside micro-scale fluidic channels?

    One possible microfabrication approach that bypasses the step of bonding involves only deposition of resists by spinnng, UV photolithography, and cure. Nevertheless, the last step to accomplish such a method requires the development of solid uncured resist which is placed between two (top and bottom) other slides generating microstructures.

    Renato Sousa Lima · Brazilian Nanotechnology National Laboratory

    Another gimmick is related to the use of the SU-8 developer vapour. The top resist tolerates high temperatures. It can be PDMS, PVC, or even cured SU-8.

  • Emilio Abdo asked a question in Bile:
    Bile digestive anastomosis

    propose a discution on the subject. have some ideas.

  • Rahul Roy added an answer in Plant Hormones:
    What are the precursors of the major plant hormones and is there a genetic control?

    What are the precursors of the major plant hormones (auxin, gibberellin, cytokinin, ethylene, and abscisic acid)? What are the major genes that control/interact with them?

    Rahul Roy · Iowa State University

    The synthesis and genetic control of hormones is a large topic, with multiple books and papers worth of information. In concise lets say a multitude of pathways  feed into the diverse hormonal biosynthesis. Most hormone synthesis is under transcriptional control due to interconnected signaling pathways like developmental stage, biotic and abiotic stresses etc. Moreover, other levels of control also exist like the classic case of cellular trafficking of transporter localizations leading to changes in auxin localization. So theres obviously a genetic  component as well as other cellular components that researchers are trying to understand. 

    I highly suggest reading some annual reviews or other review of hormone biosynthesis if you are interested in knowing more 



  • George Stoica added an answer in Complexity:
    Why does limit of function not exist when right hand limit and left hand limit are different?

    If right hand limit and left hand limit exist, that means the limit 'exists'.

    But, this is wrong.... Why??

    Even in complex case, lim (z->0), (x^2y)/(x^4+y^2) does not exist... coz depending on the path, the values of limit changes.

    Why does that mean the limit does not exist?

    George Stoica · University of New Brunswick

    Dear Chanwoo,

    It works like that in one dimension, but there's a complete different story in two or three dimensions, hence in the complex case as well. Instead, go with the topological definition, it works equally well for all these cases listed above.



  • Diego M. Gil added an answer in Dimerization:
    Is geometry optimization needed before running single point energy calculation in gaussian09 for high-resolution crystal structure coordinates?

    I have a crystal structure where there are pairs of molecules interacting strongly through hydrogen bonds. Experimentally, the molecule has been shown to form similar dimers in solution. I want to calculate the interaction energy for this dimer. Since I already have a good crystal structure showing all the interactions, should I perform geometry optimization before calculating interaction energy using counterpoise?

    Diego M. Gil · National University of Tucuman

    With the optimized structures of the dimer you can evaluate the hydrogen bonds interactions by means AIM analysis with the AIM2000 program. If you have more information about the program write me an e-mail. Best wishes.

  • Google scholar for systematic reviews: what limit on search returns?
    Are any researchers who are undertaking systematic reviews also adding a search of google.scholar? And if so, what numerical limit are you putting on results that you inspect? In some earlier trials, I found that scholar returned in the order of at least 10x more results than did the more usual sources (like Medline) which I feel would then artificially distort the number of excluded articles in your flow diagram of articles to be included.
    Wichor M Bramer · Erasmus Universiteit Rotterdam

    Google scholar does add relevant unnique articles to systematic rviews. I do over 250 sr searches a year and track all includes from those that are published, to see from which databases i retrieved them. Since one and a half year i am now using GS for every SR i search coordinate. And in half of the cases at least one unique ref is found in GS. Of the 4000 includes i traced up to now, from 80+ SRs, 100+ includes were unique from GS. data will be publishes eventually.

    I usually take the first 200 hits, that i exatract using pubslih or perish, and then export to endnote, and dedupe with my other refs. Normally of those first 200 50% is non duplicates. 

  • What are the existing studies or good instruments for studying academic procrastination?

    I am carrying out a study on the predictors, moderators and mediators of procrastination among students in Ghana. Can anyone assist me some suggestions of studies, instruments or gaps to look at?

    Jordan A. Litman · Florida Institute for Human and Machine Cognition

    There may be multiple motives that underlie procrastination besides avoiding something expected to be unpleasant or result in failure, such as the excitement of getting done under the wire. I think the jury is out to date on this one, but  check out work by Freeman http://link.springer.com/article/10.1007/s12144-011-9123-0

    And also a nice meta-analysis by Steel https://www.researchgate.net/publication/222402939_Arousal_avoidant_and_decisional_procrastinators_Do_they_exist

    On a relate note, you might also look into planning biases in initiating and completing tasks, and aspects of personality that might predict their degree, direction, and magnitude -- see further in the two Pezzo & Litman papers http://drjlitman.net/?page_id=156

  • Dominic Kornu asked a question in Mobile Commerce:
    Is anyone researching on mobile communication security in mobile commerce?

    I am investigating the security of mobile communication channels, limitations of mobile phones, and use the information got to design a conceptual securiity framework for mobile commerce (m-payments).

  • Peter Petros added an answer in Obstetrics:
    Post tumour surgery complications
    Female of age 45: Had a fibroid uterus and underwent a hysterectomy surgery of 2 years before. From that surgery she took many medications for 2 years, but has pain in the right and left hypochondrial, hypogastrial, iliac fossa as well as irritation along the line of suture.
    How can it be cured?
    Please help!
    Peter Petros · University of New South Wales

    Hi Karthik

    What you report is not uncommon after hx.

    If she also has some other symptoms such as urgency, nocturia, frequency, abnormal micturition (see ref 2 below) , she probably has posterior fornix syndrome which is a consequence of the lax uterosacral ligaments which often occur after hysterectomy.

    Treatment: (see ref 1). Make a transverse incision 3-4 cm below the hysterectomy scar and plicate the uterosacral ligaments with 2-3 non-absorbable sutures.  This approximates and tightens lax USLs. Initial cure rate is good, sometimes up to 70-80%, but it decreases over time because USL iigaments loosen again.

    1. Petros PE Severe chronic pelvic pain in women may be caused by ligamentous laxity in the posterior fornix of the vagina. Aust NZ J Obstet Gynaecol. 1996; 36:3: 351-354.

     2. Petros PEP, Inoue H Letter - Pelvic pain may be caused by laxity in the uterosacral ligaments as part of the “Posterior Fornix Syndrome”. ANZJOG 2013; 53(3):325-6. DOI:10.1111

  • H.G. Callaway added an answer in French Revolution:
    What is the crucial difference between establishment and caste?

    De Tocqueville's theory of the social-political establishment follows his analysis of the Old Regime and the French Revolution; and he argued that violent revolution came to France because the nobility degenerated into a caste and refused to absorb new people of power, affluence and influence--the rising middle class. The British upper class, led by the Whig establishment, in contrast, absorbed the new middle class, avoided revolution and remained a ruling establishment. (The Whigs were later displaced by the British Liberal party.) The French nobility retained their privileges at the expense of power and authority, while the British Whig establishment shared their privileges precisely in order to rule. The argument is, then, that one better maintains a free and stable society by maintaining a balance between the liberal democratic and the authoritative, established aspects of society. Extending De Tocqueville's ideas a bit, it seems clear that the danger of caste is especially prominent whenever the boundaries of the establishment are drawn on ethnic lines in a multi-ethnic society. 

    H.G. Callaway · Temple University

    Philadelphia, PA

    Dear Daugherty, 

    Perhaps this is my oversight, and I do not want to bring up old difference to no point. However, you have to realize that I have no control over how postings are displayed when I or others look up the question to see if there have been additions. 

    It looked to me, as RG displayed the thread, and I revisited the display on-line, that yours had been the last posting on the thread. So, I added my little note in reply, in the interest of the continuation of the thread. 

    In any case, I stand by my point that strident, ideological politics is a kind of social excess productive of divisiveness and new versions of old castes. 

    H.G. Callaway

  • Tausif Alam 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.

    Tausif Alam · University of Wisconsin–Madison


    "Topological mappings depend only on the neighborhood relation of cells and are invariant to normal spatial deformations, i,e, compression, stretching, etc. This is well understood."

    You are correct, but if taken as Ursula states, her model cannot accommodate any spatial deformations.

  • Leonard Goeirmanto added an answer in Textbooks:
    Is there anyone actively creating their own textbooks and if so, how are they creating them?
    Open source is being seen more and more as an avenue to refocus course content and deliver exactly what is needed to the learner. It is an economical solution but also it provides a more meaningful product.
    Leonard Goeirmanto · Universitas Mercu Buana

    just add another service in web to create simple and interesting books for student, tools in www.blurb.com are helpful

  • Carly Smith added an answer in Paracoccus:
    Can anyone recommend some helpful books, manuals and/or guides covering microbiology, bacteriology and methods?

    Something I can keep for a quick reference to pull off the shelf while I'm learning labortory techniques and methods for working with bacteria.  Research is focused on Paracoccus denitificans (gram-negative facultative anerobe).

    Carly Smith · National Heart, Lung, and Blood Institute

    Thank you so much for all the suggestions! I will be doing some cloning in the future.  But for now basic culturing, biochemistry, and some physiological and metabolic studies are the first endeavors.  Greatly appreciate the replies, and welcome anymore!

  • Rachel L Robbins added an answer in HTML:
    I am not able to download articles, please help?

    I am not able to download articles - the download link on all articles goes to a html document of nonsense instead of a PDF? Any advice?

    Rachel L Robbins · The Commonwealth Scientific and Industrial Research Organisation

    Thanks I'll try that!

  • Malek Alghdeir added an answer in Conductivity:
    How do I determine the conductivity of transparent thin films?

    I have been fabricating TCO of Zinc and its doped variants.But I have not come across any method of conductivity measurement,just conductance values in literature.