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  • What is the most important risk factor to predict AF recurrence after catheter ablation?

    What about recurrence risk models? score sheets?

    Adail Almeida · Hospital UNIMEC - Brasil

    I think about another important risk factor not too well recognized: Interatrial block or newly designed Bayés Syndrome.

  • Special relativity: a big Heisenberg's uncertainty principle?

    If you know the coordinates for one referential, you can only know the speed of the other. If this is true, are the Lorentz transformations incomplete? Or do they resolve the Heisenberg's uncertainty principle?


    Andrew Messing · Harvard University

    I know Galilean transformation doesn't work. It doesn't work because there is no absolute uniform motion. Alternatively, it doesn't work because classical "relativity" had assumed an absolute that everything could be seen as moving with respect to, and this assumption was wrong.

    That wasn't my point. My point was that coordinate transformations of any type are irrelevant here. Heisenberg's uncertainty principle is based on the fact that there exist systems so small that any kind of measurement/observation disturbs them. In classical physics, the assumption was that we could measure any "observable" (any measurable property of the system) arbitrarily gently. If you are in a house during a power-outage, and you have a flashlight, turning it on will not cause windows to break, tables to fall over, or poke wholes in walls. Yet light can disturb systems (recall the photoelectric effect). By "disturb", I do not mean effects like shining a light in someone's eye or other obvious effects; I mean something like the photoelectric effect in which the constituent parts of a system are reconfigured or lost the way that under certain conditions we can detect the ways in which light waves "hit" metal, causing the emission of electrons. I am also talking about visible light, not e.g., infrared or UV light (or lasers, for that matter).

    The point is that for a long time light was used as the primary way to measure properties of some system (whether via microscopes, vision, telescopes, etc.). Moreover, the disturbance caused by shining a light on something was so negligible the real source of measurement error was due to our experimental equipment. So there was good reason to believe that no matter how small or "delicate" a system was, we could always make our measurements "gentle" enough so as to not disturb the system any more than shining a flashlight at the moon disturbs the moon.

    Quantum physics changed this. The uncertainty principle is commonly thought of as some kind total cut-off: electrons are so small that anything we want to know about them is limited by this "uncertainty" line we can't cross. In reality, the uncertainty principle is actually more like a way to determine HOW certain (and uncertain) a measurement can be and in particular the relationship between a more "certain" measurement of one property (spin along the x-axis, say) vs. another.

    In fact, a lot of the "uncertainty" in quantum physics has nothing to do with the uncertainty principle. Some would argue almost all of the uncertainty is unrelated to the uncertainty principle. Whatever the case, Lorentz transforms can't suddenly make an electron stay in one place so that we can examine it's spin, measure it's velocity (by measuring its position, trajectory, and the distance traveled over some interval of time), or enable us to perform experiments in which quantum physics is temporarily suspended so that we can make classical measurements of quantum systems.

  • Low Resolution Images For Actinobacteria using microscopy - Suggestions ?

    Hey fellow researchers,

    We seem to be obtaining low resolution images under all magnifications for actinobacteria on transient slides prepared from liquid and solid cultures. Can you suggest any ways to improve the quality of the images, especially in the preparation of slides and toying with the settings of the optical microscope ?

    Your inputs would be greatly appreciated. 

    Best Wishes


    Dilantha Gunawardana · University of Sri Jayewardenepura


    Thank you both for your valuable suggestions. I will try to use these techniques and see whether the focus is stronger and images are of high resolution. 



  • Vikas V Gite added an answer in Composites:
    What are the thermal tests that can be done on Polymer Matrix Composites?


    Attached is a picture of an aircraft graded carbon/epoxy composite. Out of curiosity, what are the possible thermal tests and hence properties that can be investigated from such sample?

    Any contributions will be valued.

    Thank you.


    Vikas V Gite · North Maharashtra University

    For studying degradation of CFRP just go for TGA or STA. TGA is giving thermal degradation with respect to temperature and STA is giving some added information. But TGA is sufficient for you.

  • Firdaus Amri asked a question in Sampling:
    What's the best sampling techniques for online respondents in spesific communitiy?

    your suggestions will be helpful!

  • John Otto added an answer in HPLC Analysis:
    Can anyone suggest a protocol related to the HPLC analysis method of VFA in silages?

    I need a detaıled protocol related to the hplc method of vfa analysis in silages.

    John Otto · University of Tasmania

    I have also used GC to measure VFA

  • Daryn Dyer added an answer in Social Theory:
    Finance literacy and its impacts on social preferences?

    Can anyone please send me research papers on the topic "Financial Literacy and its impacts on social preferences"?

    Daryn Dyer · York University

    Hello Mr. Khan, I hope these documents are in the domain of what you are researching. As I went through the journals, I was looking for financial understanding/knowledge and how it impacted social preference....Good luck:

    Riedl, A., & Smeets, P. (2014). Social preferences and portfolio choice.

    Lusardi, A. (2008). Household saving behavior: The role of financial literacy, information, and financial education programs (No. w13824). National Bureau of Economic Research.

    Ackert, L. F., MARTINEZ‐VAZQUEZ, J. O. R. G. E., & Rider, M. (2007). Social preferences and tax policy design: some experimental evidence. Economic Inquiry, 45(3), 487-501.

    Hilgert, M. A., Hogarth, J. M., & Beverly, S. G. (2003). Household financial management: The connection between knowledge and behavior. Fed. Res. Bull., 89, 309.

    Fong, C. (2001). Social preferences, self-interest, and the demand for redistribution. Journal of Public economics, 82(2), 225-246.

    Rettig, K. D., & Schulz, C. L. (1991). Cognitive style preferences and financial management decision styles. Financial Counseling and Planning, 2, 25-54.

  • Jorge Ortiz Pinilla added an answer in Variability:
    Meaning of SD of dummy variables?

    I'm trying to figure out what is the meaning of standard deviation with regard to dummy variables. Standard deviation is the continuous variables' extent of deviation. But does it have the same meaning with regard to dummy variables? The dummy variables are my independent variables (along side continuous variables). Dependent variable is continuous. 

    so if I get the following result (X, Y and Z being the dummies) what do I learn from the value of SD:

    Variables        Obs         Mean   Standard Deviation       Min       Max

    X                   1016         0.70                     0.46                       0            1

    Y                   1016         0.07                     0.26                       0            1

    Z                   1016         0.23                     0.42                       0            1

    Couldn't find the answer anywhere. I'd appreciate the help. 


    Jorge Ortiz Pinilla · Saint Thomas University

    The information given by the SD is so related to the mean (p) that it becomes redundant. Nevertheless, it gives some rapid information about the degree of "balance" in the data from groups coded 0 and 1.

    For example, the mean for X equal to 0.7 means that 70% of your sample are coded 1 and 30% 0. For Z you have 23% of your sample coded as 1 and 77% as 0. If the proportions where 0.5 - 0.5, the SD would attain the maximum of 0.5. 

    For Y, p = 0.07 and SD = 0.26, sensibly lower than those for X or Z, indicating that the data are less "balanced" for the groups determined by the values of Y.

    If this interpretation helps you, :)  If not, :( 

  • Can anyone suggest articles related to the use of the balanced scorecard in higher education?

    I am interested in practical examples of the use of the balanced scorecard framework in higher education (for strategy planning, implementation and evaluation of performance).

    Imanol Ordorika · Universidad Nacional Autónoma de México

    You should follow Estela Bensimon's work at USC. Dr. Bensimon has worked extensively on balancing the scorecard in higher education.

  • Olivier Serrat added an answer in Ecosystems:
    What are the basic elements for a good management of the coastal ecosystem? how about the experiences of countries? articles or any links?

    What are the basic elements for a good management of the coastal ecosystem? how about the experiences of countries? articles or any links?

    Olivier Serrat · Asian Development Bank

    The Coral Triangle, available at http://www.adb.org/news/photo-essays/coral-triangle-book, is a 272-page book that showcases the people, places, and marine ecosystems that make this region truly remarkable. Published by ADB and the World Wide Fund for Nature, the book documents an 18-month expedition by award-winning photographer Jürgen Freund and Stella-Chiu Freund. Searching for "coastal ecosystems" and/or "marine ecosystems" at http://www.adb.org/ brings up numerous related links.

  • Meg Barber added an answer in Wound Healing:
    What is the best analysis model for repeated measures with regard to wound healing (rate of or size reduction) and also time to infection resolution?

    I am writing a research proposal for an undergrad project and I am re-thinking my primary endpoints.

    I am wondering what are the best statistical analysis models for repeated measures in regard to the rate of wound size reduction and also time taken for infection to be resolved? I have considered a two-way repeated measures ANOVA but as my study only has two treatment arms (test and control) so I am unsure if this is correct?

    Many thanks 

    Meg Barber · University of Plymouth

     Thank you Renee, I will definitely look into this in more depth. I was planning to have some form of bacteriological report in regards to the specific bacterial groups present in each treatment arm as I am aware that the number of pathogens is not sufficient to indicate antibacterial efficacy, but in light of what you have pointed out I will definitely include s/s of infection in my outcome measures. One thing I am concerned about however is the fact  that infection s/s may be absent/masked in my target population...would it be plausible to suggest that eradication of infection would be based on clinical observation and supporting culture results? 

    Many thanks

  • Luiz C. L. Botelho added an answer in Prime Numbers:
    Has The Riemann Hypothesis been solved?

    Many proposals for solving RH have been suggested, but has it been splved? What do you

    Luiz C. L. Botelho · Universidade Federal Fluminense

    Dear Thong 

    I am not an expert on Number Theory .But I have heard that what was proved was a result in Algebric Geometry supposedly related to the Fermat Last Theorem .I still think , based on my vast experience of sound  mathematical research , that book thicks 500 pages or more containing just a single mathematical proofs of results that are  only expected to be related to the main problem , must be always seen with a BARREL OF SALT .

  • Hoa Thanh Dang asked a question in Public Procurement:
    Can anyone help with research questions about Australian public procurement for construction?

    I am curious to study about procurement methods those are current applied in Australian public construction, can anyone help me start up with the research questions?

  • What the steps that is to be followed for the synthesis of a targeted drug delivery mechanism using gold nanoparticles?

    I have functionalized gold nanoparticle and i want to targt breast and colon cancer cells using the targeted drug delivery approach.please give me a step by step protocol that i will use and the chemicals that will be required. Thanks

    Ramya Chandrasekaran · Monash University (Australia)


    I am sure you can get lot of references for the targeting part. Folic acid has been commonly used to target many cancer cells. Coming to the drug delivery part, I would suggest you to use a stimuli (pH,temperature,enzyme etc) responsive system- a polymer shell around the gold. This stimuli inside the cell can cause the release of drug. I have to remind you that in this case your folic acid should be attached to the polymer shell to direct the core-shell to cancer cells.

  • Elena Venuti added an answer in Sonication:
    How do I make a stable and reproducible phospholipid/lipid/bile salt emulsion?

    Hi everyone.

    I am trying to make mixed micelles using purified egg phosphatydilcholine (PC) at various concentrations, glycerol tributyrate and Na+ Taurodeoxycholate, in a pH 8 buffer solution of 2mM Tris, 1mM CaCl2 and 150mM NaCl. There is no solvent dehydration, the reagents are simply mixing and sonicated in a waterbath(10 min at room temperature). This has been the method employed previously in my lab, the other variant using crude egg yolk as opposed to purified PC. 

    The suspensions are cloudier after sonication. A white precipitate occurs if I leave it standing for a few minutes after sonication, and suspect it may be some kind of salting out.

    1) How do I know I am actually producing micelles (rather than liposomes/vesicles), and how much of my lipids are in micellar form?

    2) How can I assure these suspensions are stable and reproducible?

    Any suggestions will be very much appreciated


    Elena Venuti · Children's Hospital at Westmead

    Thanks Titus, that is very helpful.

  • Adriano Villarosa Patac asked a question in Statistics:
    Is there any paper in Statistics that deals on Fractal Statistics?

    I am interested in working with Fractal Statistics since its development is more on geometrical rather than statistical. I would like to ask if anyone has been working on this topic?

  • Sai Kalyan asked a question in Labeling:
    How to perform classification using PRtools?

    I have data for two classes, how to label the data and perform classification using PRtools(http://prtools.org/)?

    PS: If possible please post  any sample matlab code

  • Daniel Martinez Krahmer added an answer in Palm Oil:
    What is the most affordable and reasonable way to increase abrasion resistance of carbon steel surface?

    we are in developing abrasion resistance of warm screws which are using for squeezing palm oil fruit ( containing some sand and other hard particle from farming lands). Because of their heavy weight (around 500kg) it is not reasonable to change whole material with high alloy steels or cast irons.

    Daniel Martinez Krahmer · Instituto Nacional de Tecnologia Industrial

    The idea of Ankur is very good too.

  • Dan Gwinn added an answer in Insects:
    What is the easy research methodology to study on species replacement?

    I would like to work on species replacement of indigenous insects in an area where invasive species of insects have become more abundant but population of indigenous insects have become very less infesting in a commodity. What is the easy research methodology to study on species replacement?

    Dan Gwinn · Biometric Research LLC

    The use of occupancy models to evaluate patterns in species co-occurrence is an elegant method. I would take a look at the following papers.




    Hope this helps!

  • Andrey Luchnik added an answer in Risk Factors:
    Cancer a mere matter of luck? Or is there something under-appreciated?

    It has been all over in the news lately: The majority of cancer is obtained by bad luck, not by lifestyle or inheritance. See attached. 

    Really? The data appear solid and they make sense, but the conclusion seems a bit premature: the observations are based on established risk factors in the USA and I assume (let the experts please come forward!) that these risk factors are based on occurrence. This means we do not see all those cases where the patient's immune system adequately takes care of the anomaly. 

    How does occurrence of cancer relate to failure of the patient's immune system, and can we monitor this based on adequate biomarkers? How will the statistics and the conclusions change when this factor is included in the analysis?

    Andrey Luchnik · Russian Academy of Sciences

    Dear Ijaz S. Jamall!

    You ask: "Are you suggesting that there may be a way to tip the balance such that instead of 5-20% of cancer cells, we might be able to increase the fraction that die (necrotic metaphase death)?

    Yes of course! All current methods of cancer therapy do that. Chemotherapy and Radiotherapy are mutagenic. So, because of 'weak chromosomes' of cancer cells they are dying faster than normal cells being attacked by mutagens. So that frequency of dying exceeds 50%. 

    But due to mutagens normal cells as well as surviving cancer cells acquire novel fragile chromosomes. This leads either to novel tumours (formed from normal cells) or metastases (from surviving cancer cells).

    Alternative way of therapy lies in inducing apoptosis (not necrosis) of cancer cells. That can be achieved through hypothalamus and pituitary gland signals for selective apoptosis of cancer cells. (In fact it is one and the same gland, subordinate to emotion). 

    How to achieve proper emotions? Look at the beginning of current discussion about 'happiness'.

  • Could anyone help me with articles that address the construction of a university competitiveness index?
    Create an index to evaluate quality
    Isaac Sánchez-Juárez · Universidad Autónoma de Ciudad Juárez

    Thanks Magdalena.

  • Is there any FLUENT UDF macro to replace the new mesh in each time step?

    I am trying to simulate a model in FLUENT that the geometry shape is varying by time. I was wondering can I generate different geometry/mesh each time step and subsequently replace the new mesh each time steps?  In fact, in the dynamic mesh events, there is option can manually define to replace the mesh in given time but I want to know can I use a UDF to do it automatically (i.e, load the new prepared geometry with new mesh each time step)?

    Soroush Heidari Pahlavian · University of Akron

    Hi Siamak,

    Take a look at the flowing paper. I thing they did similar simulation as the one you are intending to do (CFX was used, but the concept is similar). you might be able to contact the author and ask for details. 


    As another approach, if you have all of your geometries meshed separately (you should have say 1500 .msh files), and if all of them have the same topology (same BC, ...) you can create an event file that loads the new mesh at the end of each time step  and map the data from the previous time step on the new mesh. You can try to do it manually for a couple of time steps and if it works, writing the event (journal) file is not hard. (You need to find a way to automatically generate your mesh files!)   

    And, out of curiosity, how come that your geometry deformation is not harmonic? I am asking this because all biomedical applications that I've encountered with were inherently harmonic (they were somehow linked to cardiac pulsations).

  • Can you give me advice on repeated measures?

    A college counseling center administers assessment measures on a repeated basis (interval) to clients who use mental health services. Students complete a 62-item measure (baseline) at intake, and a brief version of the measure 34-item) at the third, sixth and ninth session (three times). Treatment ranges anywhere from three sessions to ten sessions - so, the same participants are measured over several time periods or waves, but not every participant will have the same number of observations.

    Also, I want to compare three interventions (IVs): Counseling only, Psychiatric Medication only, Counseling and Psychiatric medication

    By looking at the scores on the clinical assessment measure (DV).

    Will the mismatch in time or waves cause me problems?


    Is the 62 item baseline measure valid or standardized? What is the DV clinical assessment measure?

  • Joshua K. Hughey added an answer in RAW 264.7:
    The minimum change of amino acids and glutamine on culture media, can generate change/adverse effect/alterate cells?

    The minimum change of amino acids and glutamine on culture media (DMEM) of diferent companies, can generate substantial change/adverse effect/alterate macrophages RAW 264.7?

    Because every company have an specific formula...

    Joshua K. Hughey · North Carolina Central University

    If you're asking if a minimal change in concentration of media components can affect macrophage stasis, the answer is yes.  I've even found that the macs I work with seem to do better with certain brands of media components, particularly FBS.  I'd start with the formula recommended by the company, then just experiment with component concentrations and/or various brands.

  • Song L added an answer in GPR:
    Is there any model for estimating the strength of unbound pavement layers using GPR?

    A model which is using dielectric or any parameters that could be measured by GPR 

    Song L · China University of Mining Technology

    Acoustic velocity has been accepted as a effective parameters to estimate the Strength of cement world widely. Is there any relation between acoustic velocity and dielectric constant ? If you can find it, then ...

  • Does the central government spending play a significant role on the regional growth?

    There is a number of central government expenditure which the implementation is done in province scope such as capital expenditure, I would like to analyze the implications of the central government spending on regional economic growth and poverty.

    David Fields · Salt Lake City Community College

    It depends on the extent to which the central bank purchases regional bonds, if the central government provides necessary fiscal transfers, and the extent to which the country, as a whole, has monetary sovereignty.

  • Uwe Römer added an answer in Hydra:
    Did my Hydra detach from the tank after feeding Artemia because it became contaminated?

    I fed my hydra with newly hatched artemia, and half of them become detached and less responsive to stimulus. I took some artemia under microscope and found these tiny spheric creatures eating artemia, and could it be these guys attacking my hydra? Does anyone know what they are? 


    Uwe Römer · Universität Trier

    Hallo Thomas,

    I had the same problem irregularely turning up over the last 30 years. The microscopic photograph is not the best, but it reminds me to those problems. In all cases that we were able to back-check, we detected various species of Sporozoa. They were feeding on either naupli of the Artemia that we fed to our experimental fish or, worse, on the skin of the fish as well as on their eggs and larvae. The major problem is the rapid population growth of the parasites. This has repeatedly caused total loss of experimental groups. In fact (after 3 decades!) we have not yet found any reasonable way to strictly keep those parasitic Sporozoa out of our system. We are sure that they allready come with the vacumized cysts as harvesting contaminant. To make sure that the Sporozoa do not make it to the system, we have set up a standardized protocol to check every new can of Artemia for contamination before the naupli are used in the system. If we find Sporozoa in the test hatchin unit, we thermicly destroy the cans content and use an other one. This minimizes the risk of contamination, but of course can not exclude it.

    best regards,


  • Saurabh Dhuri asked a question in 3D:
    How to mesh a tubular frame structure such as a Formula SAE car frame in hypermesh?

    I am working on a design project which involves the analyses of a Formula SAE frame. I have modeled the frame in solidworks using weldment structures feature. The geometry is fairly simple with intersecting tubes which have been trimmed at the intersections. I imported this geometry into hypermesh in the .STEP format. I was successful in creating the 2D mesh. But when I perform the 3D tetrahedral mesh it gives me error elements and the 3D mesh is inconsistent, hypermesh is unable to choose the volume of the thickness of the tubes, instead it chooses the hollow volume inside the tubes for the 3D tetramesh. How can I solve this problem. Is there an alternative?

    I wish to perform static loading analysis and torsion analysis of the frame

  • Son The Le added an answer in Quantum Dots:
    How to calculate molarity of as synthesised quantum dots?

    i have synthesised quantum dots but I'm not able to calculate its molarity. to prepare solution of particular molarity what shall i do?

    Son The Le · Korea Institute of Science and Technology

    In my though, you should determine the concentration of QDs when you did synthesizing. For example: if you make CdSe/ZnS quantumdot, you must determine concentration right after you have CdSe core. if ZnS shell was formed, we can't calculate exactly anymore.