Q&A

ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.

Browse by research topic to find out what others in your field are discussing.

Browse Topics

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • Lin Zhou added an answer in Cognitive Tests:
    Does anyone have experience with Tg CRND8 mouse model for Alzheimer's Disease?

    I'm trying to fix a mouse model for my AD experiment which involves multiple cognitive tests at different stages of the disease. 

    It was mentioned that a considerable amount of CRND8 models don't survive over a year. I don't suppose this should be very common among AD models sine some assays are carried out later. I'm not sure if there are pros and cons worth noticing with this model. Actually I'm wondering how certain models are chosen for particular studies, despite the ones obviously don't fit the experiment design, many models seem to have largely overlapping features. 

    One major problem here is that I may not be able to work on a long term trial for years with this program, thus I have been concentrating on models that exhibit physiological / cognitive symptoms within 6 months. CRND8 model has a relatively aggressive disease onset and has more information on cognition tests in previous studies than other models found in reviews. Not sure if this is the right way to find models since I haven't got much experience in this. 

    Id really appreciate it if you can share your experience with Tg AD models. 

    Thanks. 

    Lin Zhou · South University of Science and Technology of China

    Lynn: thank you! its surely practical to double the group size regarding to the mortality rate, but is there any considerations in experimental outcomes associated with early death of these animals? If substantial number of animals died, shouldn't it imply problems with the ones that survived in the same trail?

  • What is perceived? What are the contents of perception?
    Do we perceive light, sound, and so on? Or, do we perceive the world, as such; the shape, size, location, of things in the world? Or, do we perceive the world in relation to ourselves, and ourselves in relation to the world?
    Richard Atkins · Boston College, USA

    From a philosophical point of view, the answers to this question fall on a continuum, the extremes of which are found in the developments of British Empiricism and the Scottish Enlightenment. The broadest conception is due to Francis Hutcheson, who holds that the “every Determination of our Minds to receive Ideas independently of our Will, and to have Perceptions of Pleasure and Pain, [I call] a SENSE.” C.S. Peirce inherits this view and argues that whatever is stated in involuntary perceptual judgments must be regarded as a content of perception (that is, the percept), even though it need not be veridical. Consequently, Peirce (and Hutcheson, I think) must deny that perception is a success term. On the other end of the continuum is James Mill, who goes so far as to claim that “[i]t is Light alone which enters the eye” and “[s]ome of the things suggested by the sensations of sight, as extension and figure, are suggested so instantaneously that they appear to be objects of sight, things actually seen. But this important law of our nature, by which so many things appear to be seen, which are only suggested by the feelings of sight, it requires the knowledge of other elements of the mental phenomena to explain.” The Millian view predominated until the mid-1990’s, most notably with W.V.O Quine claiming that all of our knowledge depends on “surface irritations.” However, recently Susanna Siegel and Jesse Prinz have called the Millian view into question (though not explicitly calling it the Millian view). Siegel has argued that we perceive natural kinds and Prinz has extended his dual content view of perception to sensation, though an explanation of their view lies outside of this brief answer to the question. Personally, I have a preference for the Hutcheson-Peirce view since it can make better sense of mathematical knowledge on the basis of perception (e.g. proofs of the Pythagorean theorem on the basis of perceiving relations among triangles and squares) and since the Mill-Quine view seems to require an implausible amount of offloading to the “inferential” (scare quotes because it is open question whether “inference” should be limited to refer to self-controlled processes alone) processes of the mind.

  • If its possible to achieve increase in the range of UWB signals by spread spectrum modulation technique?

    What aspect of DSSS is helping in achieving increase in range? Is this related to "Near-Far" problem?

    Steve F. Russell · Iowa State University

    Spread Spectrum Systems are useful for the following applications: 1) interference rejection, 2) ranging (distance measurement), 3) signal hiding (spreading the signal spectrum out so wide that it dissappears in the noise).

    By its very definition, spread spectrum is increasing the information theory bandwidth of a signal spectrum. When you already have an ultra wide bandwidth, and it is operating with sufficient SNR, spread spectrum cannot increase it's inherent range.

    However, if you are operating in a hostile RFI environment, with somewhat narrow interfering spectrums, spread spectrum can improve your SNR (and hence range) over what you would obtain without spreading. In essence, it spreads the interference  out so it looks like wideband noise and coherently reconstructs the original signal spectrum, thus reducing the power spectral density of the interference and increasing the SNR at the receiver.

    Good luck.

  • Is realistic wormhole possible in a Unified Field Theory?

    We know that the Unified Field Theory is an elusive dream for theoretical physics. However, there were many proposals of UFT in the past. One interesting proposal is by M.J. Goodband, which he calls as S10 Unified Field Theory (STUFT). His abstract notes: a class of Classical Unified Field Theory was presented ... Where wormhole configuration induces topological transition..."

    So it seems that wormhole is possible in certain UFT. My question is : whether a realistic wormhole possible in UFT, and are there other UFTs which allow wormhole configuration? Your comments are welcome.

    Hi Robert!
    Re: cutting fieldlines:
    Really? Oh. Okay.

    Re: Wormholes breaking SR clock-synch,
    I don't think the SR community would lose much sleep over it. They've dealt with much worse breakdowns in the past.

    In this case, I think they'd just shrug and say, “for more complex geometries you need to use GR, not SR” and refer you to their GR colleague, who'd say “Nowadays, we appreciate that SR is only a local theory. How big is local? In this case. .. if your region of space includes both wormhole mouths, and that would break the theory, then that's obviously too big … “

  • Riki Ramadian asked a question in Molecular Biology:
    I just use protocol but i do not know why use the material, can anyone recommended book for explain general protocol in molecular biology?

    in molecular biology are there book that explain why we use material in every step in that protocol or are there simple book for explain general protocol that often used in molecular biology ? example: In step 4 (bold sentence) , it explain about why we use the protocol but other step no explain,

    1. Inoculate a single colony containing the plasmid of interest in 5 mL of LB medium and  50 μg · mL−1 of appropriate antibiotics, using an inoculation loop or needle. Culture the  bacteria at 37°C for 7 h to overnight with shaking at 250 rpm. For convenience, when preparing multiple cultures, select isolated colonies with autoclaved toothpicks (cut into ∼1 cm pieces) and inoculate cultures by dropping the toothpick directly into the culture tubes. Number each colony and tube correspondingly to assure tracking. If necessary, reincubate  the plate at 37°C for 3–5 h and store the plate at 4°C.
    Notes: (1) Use sterile techniques. Handle the toothpicks with flamed forceps. Alternatively, sterile  pipette tips can be used for inoculation. Wipe the shaft of the pipette clean with ethanol before use.
    (2) Prolonged culture will increase cell density, but at the same time, the number of aged or dead
    cells increases and reduced plasmid yields can result. Rich media, such as Terrific Broth (TB), may
    be used to shorten the culture time required to reach the desired cell density.
    2. Add 1 mL of the overnight culture to a microcentrifuge tube and centrifuge at 12,000 × g for 30 s. Remove the liquid and invert the tube on a paper towel to dry the bacterial pellet  for 4 min.
    3. Resuspend the pellet by adding 0.1 mL of ice-cold plasmid lysis buffer and vortex for  2 min. Incubate the tube for 5 min at room temperature. This step lyses the bacteria by  hyperlytic osmosis and releases the DNA and other contents.
    4. Add 0.2 mL of freshly prepared alkaline solution and mix by inversion. Never vortex.  Incubate the tube on ice for 5 min. The function of this step is to denature the plasmid and chromosomal DNAs and proteins.
    5. Add 0.15 mL of ice-cold potassium acetate solution. Mix by inversion for 20 s and incubate on ice for 5 min. The purpose of this step is to selectively renature the plasmid DNA.  Some chromosomal DNA may be partially renatured and bound by proteins, which will be  extracted by phenol/chloroform in later step

  • Subhasish Mitra added an answer in ANSYS:
    Can anyone help with modeling a solar pond in Ansys?

    I will like to do modeling and simulation of solar pond in Ansys. Can anyone give a guide on how to go about it keeping in mind that solar pond get incident radiation from solar source?

    Thanks.

    Subhasish Mitra · University of Newcastle

    Hi Saheed,

    Apology for a late reply. The message unfortunately skipped my notice. I am not sure whether you have come across these following texts which should help you with the simulation methodology of solar pond:

    http://www.cder.dz/download/Jith10_29.pdf

    http://www.sciencedirect.com/science/article/pii/0038092X80904041

    http://www.sciencedirect.com/science/article/pii/S0960148102000253

    And specifically to understand how vaporization model is integrated with VOF CFD, please refer to the following paper:

    Zhang et al. / J Zhejiang Univ-Sci A (Appl Phys & Eng) 2012 13(5):361-374

    Hope it helps,

    SM

  • How can I promote undergraduate research and publication through my taught classes, since my students are not pursuing a final year thesis??

    My students are not pursuing a final year thesis but I would like to expose them to research and even start them off on publishing their papers. What do you do/ what ideas can you suggest to do this is an enjoyable and accessible way?

    Marcia Nathai-Balkissoon · The University of the West Indies, Trinidad and Tobago

    Thank you for your comments, Dr. Kangueane and Dr. Kennedy. I asked my question because I have some second year students not involved in any large projects and wanted to build into my course opportunities to enhance their research and publication skills if possible. 1 in 50 reports eventually finding their way to publication is an interesting statistic. It would be interesting to learn about the statistics from programme to programme and from university to university.

  • Justin Snyder added an answer in Cognitive Modeling:
    Are there any new cognitive models of PTSD?

    I'm looking for explanatory cognitive models of PTSD and dissociation. I'm doing research on the relationship between dissociation and PTSD amongst undergraduate students.

    Thank you for your help.

    Justin Snyder · Saint Francis University, USA

    Gareth,

    You are not over complicating things.  I think what you are suggesting is that "dissociation" over complicates things, and there are easily observable predictors of PTSD.  "Dissociation" is the frankenstein.

    I dig your take on PTSD/dissociation. I 100% agree that "dissociation is an odd and slippery concept."

    Could you elaborate on your criticisms on Foa and Brewin?  I think you are hinting at something very important.

    Justin

  • Does infinity exist or it is a product of human mind?
    What is the philosophical explanation of infinity?

    Dear, Mohammad and Ralph
    The contradictory “potential infinitude” and “actual infinitude” concepts have being accompanying us with a long-drawn-out and ceaseless “potential infinity--actual infinity” debate since antiquity. But can we really have two, three, four or even more contradictory infinitude concepts with different natures in our science? How do the contradictory infinitude concepts with different natures exist theoretically and operationally in our science? These are the questions unavoidable for anyone who studies and works in the field of infinitude.

    Regards,
    Geng OUYANG

  • Steve F. Russell added an answer in Underwater:
    What is the obstacle for underwater optical wireless communications?

    Water have complicated nature, water acts as a big obstacle in the propagation optical light which ends up with reduction of the optical transmittance in very short ranges which can be in the order of a few tens of meters. on the other hand, we can use the visible band of the electromagnetic spectrum (450nm-550nm), where water is relatively transparent to light and absorption takes its minimum value.

    Steve F. Russell · Iowa State University

    Think of it this way. H2O absorbs photons in a wavelength-dependant manner. Salt in H20 causes more absorbtion. Dirt, chemicals, and fine particles absorb and disperse the photons. Think of it as attenuation of the 'signal.' Gert was only half kidding when he said fish! Any large objects will temporarily block the photon beam.

    One of the best ways to design some reliability in the communication system is to use packet transmissions and error detection and correction coding. That way, lost packets can be retransmitted and some error correction can reduce packet loss. This is done is satellite systems.

    I think that practical environments such a sea water are also frequency dispersive which puts a theoretical limit on the bit rate of the water 'channel,' e.g., you might transmit good sharp, high rate, photon pulses but they get smeared out at the reciever.

    Good luck

  • Arpan De added an answer in Microbiology:
    How can I fix Pseudomonas putida cells prior coulter counter?
    I want to fix the cells so I can use them at a later time in the coulter counter. Will ethanol be okay?
    Arpan De · Bowling Green State University

    Ethanol:acetic acid(3:1) is one of the options but 2.5% Glutaraldehyde is certainly a better option. 

  • Can anyone express the mathematical equation for love?
    Although many believe love is a subjective expression, is there an objective mathematical function for it?
    Nelson Orringer · University of Connecticut

    One plus one equals one.

    Two lovers affirm their unity.

    This is the meaning of Aristophanes' myth in Plato´s Symposium, according to which each lover seeks his other half.

  • Xia Chen added an answer in Cement:
    What is the effect of water cement ratio on fresh density of concrete?

    Fresh concrete density and water cement ratio

    Xia Chen · Wuhan University,Changjiang River Scientific Research Institute

    Yes, I do totally agree with Prof. Hisham Qasrawi. The density of concrete depends on many factors and all raw materials per 1m3 varies with water/cement ratio. At the given water/cement ratio, cement content and water content change at the same time which yields different fresh density of concrete. Usually,  initial mix proportion of fresh concrete could be proposed according to design requirements and experience, once appropriate workability  is achieved, then the cement and water content could be determined and fresh density set. Of course, some variations and change might be necessary when performances of hardened concrete are obtained.

  • Xiaohu Deng asked a question in Surf:
    Water wave mechanics

    Why the usual(spilling wave) assumption of the wave height inside the surf zone being proportional to the water depth will conflict with the important matter of the distribution of the applied longshore stress across the surf zone?

  • Parviz Parvin added an answer in Space Science:
    Does god really exist? Or is it just a product of a weak mind?
    Our universe is entirely self-contained, natural selection is controlling our evolution,so the question is what role is there for "god" to play?
    Parviz Parvin · Amirkabir University of Technology

    Furthermore, It is logic to accept that the creator is so intelligent to open the gates for us. Hence,  god  may assign its representative (proxy) on earth. Our duty is to find him in this case. Do you have  this will to look for the god's representative?

  • Arpan De added an answer in CHO Cells:
    PH Increase in CHO cell culture

    It seems weird but there is a bioreactor run here which pH is increasing instead of decreasing. CO2 is constantly injected to the media but seems it can not help. Any suggestion ? 

    Arpan De · Bowling Green State University

    If the medium contains sodium bicarbonate, its concentration is an important factor. Too high a concentration of sodium bicarbonate compared to %CO2 will make the medium more alkaline. For 3.7 g/L sodium bicarbonate, 10% CO2 should be used. For 1.5-2.2 g/L, 5% is good enough. 

  • Louis Brassard added an answer in NATO:
    A referendum on full Scotland's independence is in progress. How will the results of this referendum affect the European Union, NATO ...?

    Scotland's independence could bring some reflections to some European regions such as Catalonia, South Tyrol, Flanders, the Basque Country. Even some ideas of ​​new state of Kurdistan can be dangerous, especially for Turkey who would like to become a member of the European Union. What are your concerns about, if any?

    Dear Perriot,

    The French identity is a relatively recent creation and one that is not totally completed.  Would you be ready to sacrifice part of this identify, to let some local part of France to have referendum?  The European identity was stronger among scientists at the time of Descartes than it is now.  The European identify suffered from the creation of the national languages such as French, English, German, etc.. Going on the road of an greater integration will necessarily means the acceptance  of loosing some national identity or at least find new way to harmonize these.  What do you think?

  • Joshua David Caldwell added an answer in Optics:
    Please any one tell my about software name to buy to calculate optical parameters (optical constants and dispersion parameters)

    Direct and indirect optical gap, tauc tail, carrier concentration to effective mass, refractive index, dielectric constants, dispersion parameters.....e.t.c.

    Joshua David Caldwell · United States Naval Research Laboratory

    www.refractiveindex.info has a lot.  Also, Palik's book is a great resource, even if it is quite old.  Otherwise, just look at all the papers out there for the materials of interest.

  • Abdul Rauf Bhatti added an answer in Plasmonics:
    How can I extract the values of data plotted in a graph which is available in pdf form?
    .
    Abdul Rauf Bhatti · Universiti Teknologi Malaysia

    Please click the link below to download it.

    https://www.dropbox.com/sh/s4jl8rdbi9nfsmd/AAAU2wQ7tg75nnU81orIddZba?dl=0

  • Are students grade-seeking or competence-seeking?
    Are the students in your program more concerned with developing professional competence or are they focused on getting the points they need to get a grade? Are we doing all we can to foster self-directed learning or do we reward 'load and dump' behavior with honors at graduation?
    Mark E Gould · Education Queensland

    Louis, the issue of motivation is a critical aspect of how the system preferences the development of performance goals over learning goals. There are many resons why this is the case, but assessment and reporting styles are a big part.

  • Ulagapriya Krishnan asked a question in Ants:
    Reg rank based ant system

    Kindly let me know how rank based ant system is more useful than other ACO techniques.Kindly let me know if there are any other materials on rank based ant system

  • Abstract in Meta-analysis: To include or not to include?

    I am performing a meta-analysis and my search was extended to EMBASE.

    As part of the process I have retrieved a few abstracts that were included in some congress abstract books. The results of these congress communications are not yet published as full papers, but still some data is potentially extractable from these abstracts and could be included in the meta-analysis.

    Should I include them and state it in the Materials and methods section?

    I know that they have low quality evidence that could possibly bias the research but wouldn't it be worse to exclude something that could be counted?

    Thank you very much for your suggestions!

    Constantine Kaniklidis · No Surrender Breast Cancer Foundation (NSBCF)

    There have been already some highly insightful and intelligent contributions and observations made on this important issue by the various contributors above, so I will confine my attention to what factual data and robust evidence from relevant studies has to say on this theme, and I will also end with a "modest proposal" that constrains abstract inclusion in, I think, motivated ways that effects a compromise across extremes. In any case, let it serve as food for (further) thought.

    To begin with, the Institute of Medicine (IOM)1 describes grey literature as including trial registries, conference abstracts, books, dissertations, monographs, reports generated and held by academics, business, and industry, and the class of "regulatory documents" (my description), namely reports held by regulatory authorities like the US FDA, the UK NICE, other government agencies. And the IOM Standards for Systematic Reviews (2011) / Standard 3.2.1, recommends searching " . . . grey literature databases, clinical trial registries, and other sources of unpublished information about studies”1, a point as I will show below that is highly arguable.

    Abstract-to-Publication Discordance
    It has been decisively established that fewer than half of all abstracts are consequently published in full, with only about 60 percent of randomized controlled trials (RCTs) described in conference abstracts reaching full publication2. This is cross-confirmed by the review of findings initially presented as abstracts at EGPRN (European General Practice Research Network) meetings where overall just 45 percent of the presentations were subsequently published3.

    In addition, a comparison of Phase III trials presented at ASCO 2000 with their subsequent full publication found that primary and secondary endpoints, primary endpoint results, statistical analysis, and statistical significance of the primary endpoint were frequently not clearly described in the abstract, with the primary endpoint results differing substantially in 42% of the abstract-to-publication comparisons conducted4. And further studies confirmed that abstracts frequently reported only preliminary results often unrepresentative of what was finally observed once all data were collected and analyzed5-7.

    To take some examples outside of oncology in deliberately far-ranging arenas, we observed that the specific topic area can influence the publication rate downward even further: the subsequent publication rate of abstracts presented at medical education conferences was 34.7%8, significantly below the mean (44.5%) reported for biomedical research. Similarly, another recent review9 conducted an assessment of the reporting quality of conference abstracts with their subsequent publication rate as full papers in the domain of sports injury prevention using CONSORT and STROBE criteria, finding that 65% had major inconsistencies (in the arenas of study objective, hypothesis, study design, primary outcome measures, sample size, statistical analysis, results, and SD/CI metrics), with results changing in 90% of the randomized, controlled studies (RCTs) and 68% of the observational studies. And there are dozens and dozens of additional studies showing comparably sobering, even distressing, levels of critical discordance.

    The Claim of Reduction of Publication Bias
    It is often argued that inclusion of abstracts and other gray literature potentially reduces the effect of publication bias. In fact, however, findings and conclusions re publication bias remain unsettled and largely contradictory with some arguing that the inclusion of grey literature reduces risks of publication bias10,11, while others argue at least as compellingly that it actually increases bias12.

    And on this issue we must be chary of a potential illogic: many authors argue that inclusion of grey literature serves to modulate the conclusions of systematic review or meta-analysis when drawn solely from "black literature" (peer-reviewed fulltext publication), and that that must be construed as a good thing. But this is problematic: it is not the case that we want grey literature findings to modulate and substantively amend our SR/MS results of black literature, but rather we should want only the findings of grey literature that are content-evaluable, by which I mean methodological-quality-assessable and critically appraisable, to have that influence, and if and only if the appraisal and methodological quality score (MQS) represents sufficiently high-quality content to meet stringent quality assurance demands (for RCTs I use the Heyland Methodological Quality Score (MQS) which I have adopted and annotated (available on my ResearchGate profile)). But as I note below, it is quite atypical for the usual conference abstract to be so assessable, an issue I take up immediately below.

    Assessable Quality
    Not only are abstract results often significantly different from final publication (the issue of discordance, as shown above), but abstracts have also typically not undergone any rigorous peer review process as generally required for journal articles, which the likelihood that unidentified bias will influence the results of the systematic review, and the mere fact of an abstract’s brevity may fundamentally interfere with both the accurate assessment of the quality of the study’s methodology and with the interpretation of its results13, while the relatively greater ease of writing an abstract as opposed to a full publication can further reduce the accuracy and quality of its content14.

    Another comprehensive review15 in oncology compared final published articles and abstracts of RCTs on systematic therapies for discordance in sample size, median follow-up, results, and conclusions, finding a discordance of 63% of the abstracts in critical data points (patient number, duration of follow-up, and results) when compared with articles, leading to the conclusion that "the majority of RCT abstracts presented at major oncology conferences include important data discrepancies compared with their subsequent published articles".

    These concerns about quality and quality assessability have led some authorities like the Agency for Healthcare Research and Quality (AHRQ) to advise against use: "We do not recommend using conference and meeting abstracts for assessing selective outcome reporting and selective analysis reporting, given the variable evidence of concordance between conference abstracts and their subsequent full-text publications"16.

    So we are left with a more nuanced and narrow principle than the blanket injunction to incorporate abstracts into the evaluative process of systematic reviews and meta-analyses, namely that abstracts - and indeed any species of grey literature - should be included if and only if they are methodological-quality-assessable and critically appraisable (and in fact, by virtue of those evaluations, found to be of overall high quality for the intent of the SR/MA being conducted). If those conditions cannot be met - and given the intrinsic nature of most abstracts not followed by peer-review publication, they are rarely met, as suggested above - then abstracts should not substantively modulate any conclusions drawn solely from black literature regardless of opinions on publication bias and other associated issues. Notice this does NOT enjoin against searching for relevant robust quality grey literature nor does this enjoin against its inclusion in SR/MAs, where high quality data should in fact always be included and welcomed, but it does temper the process to be bounded by quality-assessable and appraisable content of stringent methodological quality, with the recognition that even in this event we may nonetheless anticipate a large and significant discordance - including some fundamental inconsistencies - between the abstracts we include today, and the findings reported in final peer-reviewed fulltext publication "tomorrow", namely at some point in the future, a recognition that should sober but not eradicate our enthusiasm for abstracts (and some but not all species of grey literature) with proper and circumspect caution.

    References

    1. Committee on Standards for Systematic Reviews of Comparative Effectiveness Research. Institute of Medicine. Finding What Works in Health Care: Standards for Systematic Reviews. Natl Academy Pr; 2011.
    2. Scherer RW, Langenberg P, von Elm E. Full publication of results initially presented in abstracts. Cochrane Database Syst Rev. 2007;(2):MR000005.
    3. Van Royen P, Sandholzer H, Griffiths F, et al. Are presentations of abstracts at EGPRN meetings followed by publication? Eur J Gen Pract. 2010;16(2):100–5.
    4. Tam VC, Hotte SJ. Consistency of phase III clinical trial abstracts presented at an annual meeting of the American Society of Clinical Oncology compared with their subsequent full-text publications. J Clin Oncol. 2008 May 1;26(13):2205–11.
    5. 5. Chokkalingam A, Scherer R, Dickersin K. Agreement of data in abstracts compared to full publications. Controlled Clinical Trials. 1998;19(3):S61–S2-S-S2.
    6. Hopewell S, Clarke M, Askie L. Reporting of trials presented in conference abstracts needs to be improved. J Clin Epidemiol. 2006;59(7):681–4.
    7. Toma M, McAlister FA, Bialy L, et al. Transition from meeting abstract to full-length journal article for randomized controlled trials. JAMA. 2006;295(11):1281–7.
    8. Walsh CM, Fung M, Ginsburg S. Publication of results of abstracts presented at medical education conferences. JAMA 2013 Dec 4; 310(21):2307-9.
    9. Yoon U, Knobloch K. Assessment of reporting quality of conference abstracts in sports injury prevention according to CONSORT and STROBE criteria and their subsequent publication rate as full papers. BMC Med Res Methodol 2012; 12:47.
    10. Benzies KM, Premji S, Hayden A, Serrett K. 2006. State-of-the-evidence reviews: advantages and challenges of including grey literature. Worldviews on Evidence-Based Nursing 3: 55–61.
    11. Hopewell S, McDonald S, Clarke MJ, Egger M. 2007. Grey literature in meta-analyses of randomized trials of health care interventions. Cochrane Database of Systematic Reviews (Issue 2). Art. No.: MR000010.
    12. Martin JL, Pérez V, Sacristán M, Alvarez E. 2005. Is grey literature essential for a better control of publication bias in psychiatry? An example from three meta-analyses of schizophrenia. European Psychiatry 20: 550–3.
    13. Hoag CC, Elterman DS, Macneily AE. Abstracts presented at the American Urological Association Annual Meeting: determinants of subsequent peer reviewed publication. J Urol. 2006;176(6 Pt 1):2624-2629.
    14. Autorino R, Quarto G, Di Lorenzo G, De Sio M, Damiano R. Are abstracts presented at the EAU meeting followed by publication in peer-reviewed journals? A critical analysis. Eur Urol. 2007;51(3):833-840.
    15. Booth CM, Le Maître A, Ding K, et al. Presentation of nonfinal results of randomized controlled trials at major oncology meetings. J Clin Oncol 2009 Aug 20; 27(24):3938-44.
    16. 16. Balshem H, Stevens A, Ansari M, et al. Finding Grey Literature Evidence and Assessing for Outcome and Analysis Reporting Biases When Comparing Medical Interventions: AHRQ and the Effective Health Care Program. Agency for Healthcare Research and Quality. AHRQ Methods for Effective Health Care. Nov 18, 2013. At: http://www.ncbi.nlm.nih.gov/books/NBK174882/?report=printable.
  • Steve F. Russell added an answer in Wavelet:
    How can I find the best wavelet for a determined problem?
    I did some research to find that answer and so far I got nothing. The closest answer that I found is: Trial-and-Error. Is that right? Any other suggestions?
    Steve F. Russell · Iowa State University

    Naresh and Aparna are asking good questions. It really depends on what you are trying to do. The problem is generally covered under the broad topic of approximation theory which basically says you want to take data and use some orthogonal basis 'vector' set to represent the data. For example, if you are working with the output of a stationary process, the Fourier Transform can give you orthogonal coefficients that represent the 'signal' you are approximating. Where I have seen the wavelet transform work best is in the area of image compression. The JPG standard uses the wavelet transform very effectively. You can vary the accuracy of the wavelet respresentation of an image by changing the degree of the transform. That is why image processing software usually lets you choose a 'quality factor' for the transform representation. In essence, the high-spacial-frequency information in the image is removed and the image gets more blurred as you increase the compression.

    So, ask your question again with more specifics about what you are trying to do and we might be able to offer suggestions.

    Good luck

  • Jelena Milic asked a question in Factor Analysis:
    Can anyone suggest good examples of social sciencies surveys where factor analysis were conducted using SAS software?

    I plan to prepare a survey on the quality of housing, user satisfaction and future expectations. Personally, I have never used SAS, but got few suggestions that this software is better (and more accurate) for this kind of analysis, especially in the field of the architectural research. Currently am searching for successfully conducted studies in order to find more about the process and how to prepare a questionnaire.

  • Fozle Khoda added an answer in Research Methodology:
    w

    w

    Fozle Khoda · University of Western Sydney

    thanks

  • Geng Ouyang asked a question in Tortoise:
    Is the divergent proof of Harmonious Series a modern version of Zeno’s Paradox?

    The problem disclosed by Zeno’s Paradox is still there and the exactly same idea is still working well. Let’s see one of the modern versions of Zeno’s Paradox
    1+1/2 +1/3+1/4+...+1/n +...                                  (1)
    =1+1/2 +(1/3+1/4 )+(1/5+1/6+1/7+1/8)+... (2)
    >1+ 1/2 +( 1/4+1/4 )+(1/8+1/8+1/8+1/8)+...         (3)
    =1+ 1/2 + 1/2 + 1/2 + 1/2 + ...------>infinity                        (4)

    Such an antique proof (given by Oresme in about 1360), though very elementary, can still be found in many current higher mathematical books written in all kinds of languages. There are two explanations for it:
    1, Infinite brackets can be placed into the infinite items of series (1) to change it into a new infinite series (3), which is an infinitely increasing series of Sn ------>infinity . Then series (l) is said to be divergent because of the divergence of the new series (3).
    2. Finite brackets can be placed into the finite items of series (1) to get Sn bigger than or equal to Kx1/2 (where k is bigger than any positive number presented). Now to get the limit when n------>infinity then k------>infinity , so Sn------>infinity and series (1) is divergent.

    We meet a modern version of Zeno’s Paradox------- Harmonious Series Paradox: the runner in Zeno’s Paradox is exactly that of “brackets-placing rule", while the tortoise’s walk is exactly those items in harmonious series. Although the runner can run very fast, the tortoise is surely in front of him theoretically --------although the “brackets-placing rule" uses up plenty of items in the infinite harmonious series, there still be unlimited items in the infinite harmonious series awaiting to be treated theoretically. So, the runner can never catch up with the tortoise in Zeno’s Paradox while the “brackets-placing rule" can produce infinite numbers bigger than 1/2 and easily change an infinitely decreasing series with the property of un into an infinitely increasing series with the property of un .


    We are facing a strange thing: the result of Zeno’s Paradox has been acting as a negative example troubling people for more than 2500 years but the result of Harmonious Series Paradox has been acting as a basic theory of mathematics producing many mathematical conclusions.

  • What are your views, perceptions about magic?

    magic is used to describe an influence, effects, to express our feelings towards beautiful things such as music, literature.,,,etc.

    what is the realty of magic? is it a concept of our brains? can be learnt? is it a science? or a myth?

    please share your valued opinions 

    Gerald Vineyard · The University of York

    This answer may belie stupidity, but there can be a valid explanation.

    I think magic is real in terms of it is something we do not understand yet, when we have a valid explanation or operationalisation of the phenomena. It ceases to be magic, but becomes a form of science. 

    So, what I should describe it as should be a pre-science, an idea before experimentation begins. After the idea has been tested and passed through the "rigours" of science, remember journals are not as rigorous as they used to be, then it may become a "fact", yet if there is no explanation it could be become a myth. 

    Remember legends and myths have some fine-grained truth or fact from reality in them.

    Regarding, whether magic is a concept of our brain and can magic be learnt? Ipso de facto is an interesting question. I think the concept of magic can be learnt, but at the same time it depends on the learning history  and if we do not have an explanation for such a phenomenon like why do some people may be able to fly when mediating, then we would assume it is a form of magic and it has been constructed through the mind or brain, whichever one may be enjoyed. 

    I hope this answers your question.

  • Orders about ANSYS mass matrix and stiff matrix - any thoughts?
    I can get mass matrix and stiff matrix of whole system by ANSYS. Assume one system has 100 nodes and each node only has two degrees (x, y). How can I get the rows in mass and stiff matrices corresponding 30th node's x direction?
    Paul Augustine · University of Wisconsin - Milwaukee

    Try this code:

    FINI

    /AUX2
    FILE,'file name','full'
    HBMAT,Stiff_HB,txt,,ASCII,STIFF,NO,YES
    HBMAT,Mass_HB,txt,,ASCII,MASS,NO,YES

    FINI

    Include this code in your APDL code. After running the code check your ansys directory . You will find both and stiffness matrix there in txt format. The "file name" in the second command line must match with your file name. And you must include the code for  full modal analysis prior to this. Sorry for the late reply, Hope this helps ,if you couldn't find an answer to your question.