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

5
Can we apply Roland Barthes textual analysis from mythologies to literary texts ?

I need references on this topic for a research article. Empirical analysis would be good.

2
How to define quality in sistematic review and meta analysis?

Please, can someone suggest me what is the best tool to use in a systematic review to determine the quality of each clinical trial included in the review itself? I'd like to use a tool that provide a qualiy score for each included paper. Thanks!

For RCTs the Cochrane Collaboration tool, which grade the random sequence generation, allocation concealment, blinding of participant and personnel, blinding of outcome assessment, incomplete outcome data, selective reporting and other biases. For evaluation of nonrandomized trials the methodological index of non-randomized studies (MINORS), or ACROBAT-NRSi tool, or Newcastle-Ottawa scale.

2
Do you have Filip Stanislavov’s Abagar in your library?

I am looking for information on the whereabouts of copies of Filip Stanislavov’s Abagar, which were printed in Rome in 1651 by the Propaganda Fide (see, for example, http://www.worldcat.org/oclc/500346281, http://en.wikipedia.org/wiki/Abagar). My starting point is the list published in Rajkov’s 1979 monograph Абагар на Филип Станиславов. Рим. 1651 г., but I would be interested in information on copies in any library. My e-mail address is per.ambrosiani (at) umu.se.

+ 1 more attachment

Thank you so much for checking in the Polish libraries. There might well have been copies in Poland, but unfortunately I have not yet seen any references.

7
Why is there differential detection of His tag with Tetra-, Penta- or 6xHis tag antibodies?

I have several his-tagged recombinant, purified proteins that are being detected in varying degrees by differentially his-tagged antibodies.  I understand that sometimes part of the tag can be hidden, so that a 6xHis-tag antibody may not be able to pick up a tag where only 4His residues are available.  What I am unclear on is why (this happened yesterday) a 6xHis-tag antibody would pick up a 6xHis tag well, but a penta-His tag antibody or tetra-His tag antibody used to detect the same protein would give no signal??  All experiments are done under non-denaturing conditions so proteins are in their native state.  Thanks!

Update: I wasn't able to track down the epitope that these antibodies are raised against.  It may be proprietary information for the companies.  I am now trying to understand how the tag can be partially "hidden".  Is this due to some ionic interaction between the tag residues and protein residues? It seems to me that the tag itself should not really have tertiary structure, and should be exposed to the solvent for the most part.  When looking at protein structure in pdb or pymol, I wonder if I should be looking at the water accessible regions for portions where the tag may not be water accessible, or some other category like a space filling model.  Can anyone comment?

5
Is it possible to compare the beta series of 2 groups that completed the same task but with different scanning parameters?

Is it possible to compare the beta series of 2 groups that completed the same task but with different scanning parameters (different TR, TE, pulse sequence), provided that the same preprocessing steps and 1st-level GLM would have been applied to both groups?

Thanks for your much appreciated input!

Yes I think taking all the ideas above lead to good answer to the question.

good luck

• Bertrand Mocquet asked a question in Digital:
New
Which digital device develops most of digital uses in your university? for you ? for the students ?

all digital devices develop the uses of digital technology, what are the most efficient in your university ?

5
How do you change the pixel size of an image using Erdase or GIS?
for a landsat image.

Dear Safinaz Ali

The software Erdas using yellow marked areas that can be changed pixel size (Attached image)

2
What is a best university for a phd in knowledge management?

i am trying to apply for phd scholarship in information system focus on knowledge management.

Dear Ulrich

Thank you very much.

2
Can we make a Linear Polarization Measurement device experimentally?

I am on a research which deals with service life prediction due to chloride laden corrosion. Within my lab experiments, I need to measure the corrosion current density. For that I intend to use the Linear Polarization Resistance method.

But, my lab facility lacks linear polarization device, nor a potentiostat equipment. In that case, would I be able to make one to measure the polarization resistance of the corroding rebar?

I want to measure the current for different polarization values to obtain the Polarization resistance. Please follow the attached plot.

Thanks Stephen.

What you have sent is exposed to gas. Can this be utilized to measure the corrosion current in terms of microAmps/sq.cm ?

2
Kindly suggest new topics for Research in Accounting and Auditing?

Kindly suggest new topics for Research in Accounting and Auditing?

May be environmental accounting and information tecnologies... I mean the ways of  implementing environmental accounting in ERP's.. Environmental cost measurements...

4
Would you please help me to find prior studies regarding "the relationship between sense of community and communication"?

Hi all, I need some related studies in regard of "the relationship between sense of community and communication" to be reviewed. I need to know what have been done on this topic. I have searched for it but I could not find many of them. Only one!

Would you please let me know if you have already done a similar research or have a similar paper in your archives?

https://www.researchgate.net/publication/258173828

Also check the work of Anita Blanchard

• Source
##### Article: Communication, community, crisis: Mapping uses and gratifications in the contemporary media environment
[Hide abstract]
ABSTRACT: The article analyzes how community members who were evacuated from their homes use various media, and especially the internet, to keep in touch, receive and disseminate information and express their opinions. Of particular interest are the differences between members of various groups, who differ in their decision whether to relocate in Israel with the rest of the original community or not, in media usage patterns and sense of community. The findings demonstrate that evacuees use diversity and multiplicity of media, where various media are used for different purposes according to need. Small media, with a rather limited and local reach (such as pamphlets, SMS, niche websites and small-scale meetings) are predominantly used for most of the needs, overshadowing mass media usage. Correlations were found amongst various media usages, and between the usage of various media and users’ sense of community. The study demonstrates how contemporary media users use a variety of media depending on their circumstances and needs, and how media usage assists in establishing and maintaining a sense of community after the forced transition from the communities of origin.
New Media &amp Society 02/2012; 14(1):98-116. DOI:10.1177/1461444811410401
6
How can I pseudonymize data from media (newspaper) articles without loosing them as a "real" source?

Hello out there! I am struggling withe the pseudonymization of my qualitative data. Hopefully anyone can help, I couldn't find useful literature yet.

My datasets consists of data from semi-structured interviews and articles from daily newspapers.

I want to pseudonymize all data. I understand how it works for the interview transcripts, but I am struggling with the newspaper articles.

What do I "leave" for the reader to make sure that it belongs to a "real source" and I am not just making things up?

Do I keep the newspapers name and date? but than it would be easy to find the

article. If I find pseudonyms, will it be accepted as a source, even if noone can look at the source to prove my findings?

If anyone has some experiences or hints for literature, I would be more than happy!

Thanks!

Yes, that's the point. I am analyzing 20 cases with at least 3 "critical" ones. Do you think  it would be an option to just take the parts of the newspaper articles, I am interested in, pseudonymize them and add them to the annex of my work?

99+
Do you agree with Stephen Hawking's recent conclusion that black holes don't exist?
Black holes don't exist. I published this many years ago. Cantor's Universe doesn't allow the concept.

Stephen Hawking now came up with the same conclusion. Read: http://www.spektrum.de/news/es-gibt-keine-schwarzen-loecher/1222059

In my opinion he is right this time. What is your opinion? Was he right then or is he correct now?

@All

All we seem to know, is that, out there, stars exists that move too fast for the visible mass they encircle. I doubt whether the true reason of this high speed is really known. Let's call it the effect of a black hole, even when we don't know whether these stars are sucked in or spewed out of the BH-centre. Since some time, I wonder whether what is called a (massive) BH comes up to my expectation that it is also a hotspot source of background radiation, is it? It could assist to support my approach. But unfortunately, I have no access to the corresponding data.

Btw, dear Victor, I see neither a mathematical nor an experimental reason to believe that the speed of light within vacuum shouldn't be constant.

Also, I don't see a reason for not-considering Doppler for the frequency of light within a galaxy. However, I see a reason to doubt the validity of the applicability of the effect for other galaxies as far their average frequency is concerned. From this doubt, that has its origin in algebraic (numerical) physics, I dare to conclude that a steady-state universe is  a possibility.

56
What is the role of scientific conferences ?

Meeting, business, tourism or others ! ...

Dear all,

Good day,

Yes dear Napoleon Ono Imaah and all, generally the Scientific conferences have a scientific character role.

You are quite right dear Dr. Nabil many researchers find that the Scientific conferences are nice for tourism.

Regards

10
How do I fit Fano asymmetric peak?

In the attached paper, fig.3 shows the asymmetric fit using eqn(1), what I can make out is that I is the dependent variable whereas w is the independent variable while w-dwis a constant, while gamma(linewidth) and q are derived from fit (how?)

I need a base to start I am completely blank on this right now and I need your help!

Hello Kai,

Thank you very much for your quick answer! The definition of oscillator strength given by the wikipedia article is exactly what I have in mind: coupling strength between light and exciton excitation.

In fact, I do not need to an absolute value of the o.s., but am looking for a relative measure to see how the o.s. evolves as function of another parameter such as temperature. So I have taken absorption spectra of my sample (a 2D semiconductor, MoS2). Normally for most semiconductor quantum wells (most compareable to a 2D semiconductor), the absorption spectra show a Lorentzian shaped features that can be easily fitted. In this case, the integrated peak intensity (peak area) is taken as a measure for the absorption strength, which in turn is proportional to the os.

However, I can not simply integrate the fano type resonance, because it has very long tails that don't converge within the fitting range. Just taking the amplitude as a measure for the absorption (or o.s.) might not be acceptable either as this approach does not consider the broadening of the fano resonance at higher temperatures. So I though of the product of amplitude and width.

Unfortunately, I still have not identified the origin of the continuum of states that interfer with the discrete exciton resonance. It would be good to know if the q factor is directly proportional to ratio of the dipole matrix elements. Is a q factor of 1.2 telling me that the dipole matrix element of my discrete resonance to the one of the continious resonance is 1.2 to 1?

I will try and see, if can get access to the book you pointed out. Thank you so much so this advice! The main library of the chair for x-ray technology might also have it.

21
In GR, can we always choose the local speed of light to be everywhere smaller that the coordinate speed of light? Can this be used in a theory?

It seems that many, if not all, solutions of Einstein's equations, such as black holes and grav. waves, can be given coordinates x\mu in such a way that the local speed of light is always slower than the coordinate speed of light. Think of gravitational lensing: the index of refraction of a gravitational potential always seems to be >1, in practical examples, so a gravitational potential slows light down, and never speeds it up (if coordinates are chosen carefully). This wouldn't be true for a negative-mass Schwarzschild solution, but that seems to be outlawed in nature.

Now this was only a conjecture, I have not attempted to prove it. How would a rigorous mathematical theorem be formulated? And did anybody - and here I mean a wise person, not the average blogger - ever try to do something interesting with this observation? Like constructing a “hidden medium” for curved space-time?

@Grantham:  the Planck length and time do seem to have a direct interpretation in quantum gravity when you look at the Bekenstein bounds. There is a direct consequence of  Hawking's radiation phenomenon:  from the fact that the derived temperature of a black hole is 1/8 pi M in Planck units one can derive directly that there is one bit of information per Planck-length^2 (up to a simple numerical constant) on a black hole horizon, which determines the quantum microstate a black hole can be in. According to Bekenstein this is an absolute maximum of information one can cram onto any surface. These are rather straightforward arguments. Although there is no super-solid proof of these things, since information is a delicate subject, they do suggest that there is a natural cot-off for information at the Planck scale, and that therefore, space and time are likely to be discrete. My conclusion is, if there's any limit on the information in nature, it's at the Planck scale.

Important note however: if there are extra dimensions, then also the horizon has extra dimensions and since also in that case the total amount of information should be the same per unit of area, the info will be much more dilutely spread over this multi-dimensional horizon ...

26
How can we classify or group oscillators ?

So far I have found that the number of amplifiers may be used as follows:

Oscillators type A:

1 amplifier and a feedback circuit.

This is the Barkhausen topology

Oscillators type B:

2 or more amplifiers and a connection circuit.

This is the Non Barkhausen topology

Oscillators type C:

No amplifiers !

These oscillators are based on a dynamic negative resistance e.g. a tunnel diode

In short

Oscillators are nonlinear electronic circuits

which are searching for a bias-point

.

Oh, for Heaven's sake, Lutz and Erik!  It's time to

throw Heinrich Georg Barkhausen into the ocean

and get on with MODERN design.

.

Surely, in this day and age, we understand that

what he wrote, some 80 years ago, we of today

regard as nothing more than a self-evident truth.

If one really, deeply, passionately understands

circuits, feeling the life-pulse of the components

in one's heart, has electrons flowing in his veins....

there is NO NEED FOR RULES OLD OR NEW.

'

.

Barrie

8
I am looking for scholarly articles on the effects of unofficial social media communications on emergency management, does anyone know of any?

There is an official process that is commonly followed in posting on line communications about emergency events. However, when unofficial social media communications are involved many things result such as Conspiracy Theories. I am looking for empirical evidence which shows the negative effects of unofficial social media communications on emergency situations/management.

Shannon,

The Ferguson, Missouri riots of a year ago are a textbook example of how NOT to do official emergency communications.  I will not call it a "conspiracy" but there was an agenda motivating many of the general public posts about the death in Ferguson.  By the time the police and city began trying to tell its version of what happened, a large number of people had already been persuaded that the official information was covering up the truth and was not trustworthy.

Rather than a "conspiracy" I think this was more "crowdsourcing" the facts and socially defining "the truth."

• Gareth Healy asked a question in Dissertations:
New
What would be the best way & what are the key factors should i be looking at when testing a subject with blood flow restriction (occlusion) training?

I am wanting to write a dissertation on this subject and what other professional opinions on how to go about it

99+
If any coordinates will do in General Relativity, is spatial curvature necessary? Is GR more complex than necessary, and is curvature verified?

GR was introduced along with the principle that not only is no coordinate system preferred, but that any arbitrary coordinate system would do.  The complex mathematical machinery of covariance was introduced (including tensors) to express the laws of physics, any of the laws not just GR, in arbitrary coordinates.  This allows coordinate systems in which the distances vary with position and orientation, and in which the speed of light is non-isotropic (varies by direction), and such coordinates are routinely used in famous solutions such as Schwarzschild.

So, it is not just the curvature of Riemannian geometry that requires complexity, but most of it is required by independence from coordinates.  And if indeed physics is independent of coordinates, can coordinates be found for solving GR problems in which space (if not spacetime) is flat and therefore graspable to the ordinary intuition?

For an introduction to analysis of orbits using only time dilation, not  spatial curvature, see paper linked below.  GR was derived from the equivalence principle on the assumption that curvature was the only way to explain equivalence, but this is an argument not a proof according to GR verification authority Cliff Will.  If another method is available, it becomes a weak argument.  Is there empirical proof of curvature?

• Source
##### Article: Hamiltonian analysis using time dilation
[Hide abstract]
ABSTRACT: Frequency and therefore time dilation is a function of potential in a gravitational field, as in for example "gravitational redshift." We consider using time dilation as a proxy for potential in a Hamiltonian. Thought experiments illustrate that redshift, or time dilation differences, account for the total energy potential difference between locations in a gravitating system. Unlike the weak field limit or so-called linearized-GR, we use a time dilation formulation of all motion. Therefore one might expect that a Hamiltonian so formulated gives the full and correct equations of motion within such a system, and we find that it does, but only up to coordinate singularities and not including rotational effects unrelated to potential such as Lense-Thirring.

Ah, Klaus, I'm very sorry, but I have been editing my post extensively, and I see that you answered the early version.  I have trouble seeing and reviewing the smaller text in the limited size edit window, so I post and then review.  I did not really get much out of your reply.  I would not suggest you spend any more time on it.  Unless maybe to read the final section where I analyze whether I made a couple of mistakes in my comments, made in great haste because I was really not motivated to make a post, only responding to Stefano's request.  I will be more resistant to Stefano's urgings in the future, because I agree with the majority of editors that now there is no more to be got out of this problem.

I stand by my final conclusion that if Dick and Jane's journeys are identical, except for who is in the lead, then when they finally stop they will again see Mom and Dad's clocks synchronized, and identical amounts of time elapsed on their own clocks, and therefore are the same age. And that without such a final comparison, any apparent differences in age are due merely to conventions of simultaneity.

1
Opinion on statitics?

My new "read" number is lower than my former "viewed" number but higher than my former "downloaded" number.

I assume that this changed because NOW, when you look at a publication, the abstract or full text automatically downloads, if available. Therefore, the "viewed" and "downloaded" metrics are no longer separate.

1
How may I prepare 100ml Tris-Urea Buffer for protein extraction?

I have prepared some stock solutions which are required for Tris-Urea Buffer (0.05M Tris HCl, 2% SDS, 5M Urea, 1% B-merceptoethnol). Each stock solution are about 100ml volume.

Now I need to know which amounts would be taken from these stock solutions to make 100 ml Tris-Urea Buffer.

there are two ways to prepare 100ml Tris-Urea Buffer.

1. you have to calculate volume of each chemical which is required, for this use dilution equation: M1V1=M2V2.

M1=concentration in molarity (moles/Liters) of the stock solution

M2=concentration in molarity of the dilute solution (after more solvent has been added)

V1=volume of the stock solution (unknown), and

V2=volume of the dilute solution.

(here you do not show the concentrations of stock solutions)

2. you can calculate the amount of each chemical for 100ml (required concentration or molarity) and dissolve all in little amount of DW and then add more DW to make final volume100ml.

• Abdul Hamidu asked a question in Article Writing:
New
Does any one have articles or write ups on Community Power Structure of Rurals? or Impacts of Community Power Structure on Community Development?

it could be a thesis or an article.

2
How to calculate gap between grain size in thin film?

I have XRD pattern of thin film. I have calculated structural properties from the XRD spectra. I have also SEM micrograph of these film. The shape of grain size is hexagonal. Now, I want to calculate the gap between the garin size. Please guide me. Thanks.

try to use SPIP software on you SEM image( better to have AFM(3D) image) and compare them with XRD result

chose particle and pore analysis

38
Is there a book in English where one can find characterizations of zero-derivative (stationary) points ?

In non-English literature two  such characterizations for C2 functions of the single variable can be found in the text Neralic, Sego: Matematika (second edition), Element, Zagreb, 2013 (ISBN 978-953-197-644-2) but they do not seem to be widely known. They appear to be important in analysis, calculus, optimization and other areas.  Where can one find such results in functional analysis ?

Dear Sanjo,

At first glance I can say the following:

Case 1. If $f'(x^*)=0$, it seems that f has the quadratic envelope property. For example let $x > x^*$. By Lagrange $|f(x) - f(x^*)|= |f'(c)| |x- x^*|$, where $x^*< c< x$ and by Lipschitz derivative property of f'

$|f'(c)|= |f'(c)- f'(x^*)|\leq L |c - x^*|\leq L |x- x^*|$. Hence f has the quadratic envelope property.

Case 2. $f'(x^*)>0$. Then f has no "Morse property".

In further discussion we can see whether I overlook something.
Cheers,
Miodrag

30
Within the framework of quantum mechanics, what accounts for the apparent irreversibility of time?

Within the framework of quantum mechanics, what accounts for the apparent irreversibility of time?

A brief note clarifying why clocks and rulers are different. Once one accepts that the flow of time is irreversible, then the measurement of temportal duration must be based on some kind of periodic motion. That is to say, clocks measurements  must be inherently discrete, just as Quantum Mechanics is. Straight rulers can be treated aas a continuum. Thus one is dealing with the distinction between the discrete and the continous. There are some issues involved with using a particle in moving with a uniform velocity as a clcock. This does not of course work in the rest frame of the particle itself. Also, measurements based on the arrival of this particle at various places must involve some loss of energy, such as a light signal which goes from the marker to the particle.

Fortunately, uniform velocity (eg the path of the electron) is not available in quantum mechanics. The only universal way of setting up a "continous" as opposed to a "discrete" clock is through a translation from "time" to "space" and that is accomplished by relativity, which tuns time into a spatial dimension.

3
Any suggestions on research topic in the field of digital image processing?

I am interested in image enhancement, sentiment analysis and image depth estimation. Also I am reading up about high efficiency video codec.

Thank you for your suggestions. I am trying to decide my thesis dissertation topic and I did not find a better forum than researchgate as there is a vast research experience here. I am currently brainstorming myself to decide on a topic. I am very keen on image characteristics, features and processing. Certainly the fields suggested are quite good to start my thesis in.