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  • David Hugh-Jones added an answer in R:
    How can one generate GAM and GAMM models without using R or within R?

    I have been trying to generate generalized additive models (GAM) in R. For some reason, my commands are not working. For instance, a command such as fit <- gam.fit(data[,-1], data[1]); does not run. What is correct way to generate GAM models in R? Can someone give an explicit example of a GAM model. And are there other softwares other than R that can generate GAM models.

    David Hugh-Jones · University of East Anglia

    another possibly useful R package is VGAM (Vector Generalized Additive Models, with gam as special case). Very flexible and quite well documented if I recall.

  • Saman Parvaneh asked a question in HRV:
    How do you report and interpret the frequency-domain analysis of HRV? Do you report both total power and normalized unit?

    I am looking for a suitable approach for reporting HRV parameters extracted in the frequency domain (VLF, LF, and HF) and their interpretation:

    - Do you report both power and normalized unit values for LF and HF?

    - For physiological interpretation, do you use total power or normalized unit?

  • Yazeed Alsharedah added an answer in Soil:
    What causes a slightly curved line of e-log sigma from oedometer tests on normally consolidated materials?

    I have done some Oedometer tests on my fine soil which is normally consolidated clayey silt (It was a slurry and I consolidated it using bottom-perforated mold and a 1.25kPa surcharge). I got an initial curved portion of the best fit line for e-log sigma curve. Do you know what the reason(s) could have been? any suggestions?

    Yazeed Alsharedah · The University of Western Ontario


    Thank you for your response. They were slurry of water content of 62% and I consolidated them in a perforated mold for one day at 1.25kPa. Then, I mix them slurry of reduced water content in the mold  and poured that in the consolidometer ring. Water content at that time was above the LL; therefore, fully saturation is something warranted.

  • 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


    According to your initial claim, the following is what you think happens:

    "...in fact since the membrane is permeable to all kinds of ions and molecules..."

    I was simply being accommodating, thinking about facilitated transport systems that do not require energy (not dependent on consumption of ATP or GTP). 

    If I gave you a list of dozen of such entities, how would you solve the problem at hand?

  • Renee Cordrey added an answer in Surgery:
    Is the use wet-to-dry dressing still in practice for open post-operative wounds?
    If not, what are the latest recommendations for the same? Do we have an effective, evidence based practice for the same?
    Renee Cordrey · George Washington University

    Wet to dry dressings should not be used in open surgical wounds unless it's full of loose slough and you want to debride it.  (And, in that case, it's barbaric and I still don't recommend it.)  They are no longer the standard of care, and in the US, if used in a nursing home without the indication of debridement, the facility can be cited by state surveyors. There are lots of problems with wet to dry dressings, ranging from loose cotton fibers becoming foreign bodies, to not blocking bacteria, to disrupting granulation tissue formation and drying out the wound. I wrote this review paper about the use of gauze.  Cordrey, R. (2010). Gauze, Impregnated Gauzes, and Contact Layers. Advances in Wound Care. C. K. Sen, Mary Ann Liebert, Inc. 1.

    See also:

    Spear, M. (2008). "Wet-to-dry dressings-evaluating the evidence." Plast Surg Nurs 28(2): 92-95.

    Armstrong, M. and P. E. Price (2004). "Wet-to-dry gauze dressings: Fact and fiction." Wounds 16(2): 56-62.

  • Nick Dygert added an answer in Rare Earth Elements:
    Could you please suggest me a book or document about partial melting degree calculation via rare earth elements data?

    I used the Shaw (1970)' s partial melting degree calculation (Ce-La, La/Nd-La) and got some results, and want to compare my results with other calculation methods (Rare Earth Elements). Thanks for your interest.

    Nick Dygert · University of Texas at Austin

    Hello Alican,

    Can you explain what you are trying to model more specifically? It sounds like you already have the equations for modal and non-modal batch and fractional melting, but you might find Lectures 9 and 11 in the attached link useful summaries.

    Nick Dygert

  • Timothy Wiegand added an answer in Dexmedetomidine:
    Does Dexmedetomidine work better than Clonidine for alcohol withdrawal in stable/recovering ICU patients? No formal research yet, any comments?

    Looking for some comments on your experience of using these two drugs in the above setting. Benzodiazepines have been recommended, but can sometimes be inadvertently deliriogenic! Despite adequate patient selection, there appears to be some inter-patient variability with Dexmedetomidine and clearly there is a cost implication that comes with it. Although Clonidine is cheaper, it has issues with rebound hypertension and being not as effective in my experience so far. Would be interested to hear your thoughts.  

    Timothy Wiegand · University of Rochester

    Regarding the question on difs between dex/clonidine it seems that it is that dexmedetomidine is titratable but it costs much more than clonidine.  That said clonidine often works just as well as dex e.g. using appropriate oral doses titrated up to effect with a clonidine patch placed to facilitate a wean of the oral doses.  I use these adjunctively to GABAergic agents such as phenobarbital or diazepam or propfofol (although often this is just short-term to facilitate rapid control).  So both work, I think they work best adjunctively,  dex is easily and rapidly titratable but expensive.  A quick pubmed search will uncover quite a few nice articles including reviews, and other publications regarding use of alpha-2 agonists for alcohol w/d.  Using alpha-2 agents adjunctively to PB or benzos allows for less of the more 'deliorgenic' GABAergic agents.  One of the most important aspects in limiting delirium, however,  is rapid control.  Also, I've found that combination of patch and oral clonidine allows for a smoother taper and less rebound.  Use of phenobarbital (getting rapid control)  seems to then allow for an 'autotaper' as the drug redistributes from fat stores slowly and as long as there wasn't an 'overshoot' with the dose (incremental doses given with MD at bedside (e.g. 130 mg increments)  allows for precise dosing to effect.  We have a nice PB protocol that I would be happy to share.  There is some interesting literature in Annals of EMed on use of PB from the ED -rapid control and d/c for only simple w/d patients (1987 Annals EMed paper)  I will look for and post.

  • Whot method of Heavy Oil Recovery is most universal ?

    It all depends on the properties and geology of the particular Oil Deposit. Russkoe World Document uploaded on my personal RG site partially answers this question.

    Other participants may have different opinion. I hope to hear their voice.

    Barbara Sawicka · University of Life Sciences in Lublin

    Thank you Alex, you are great

  • Renee Cordrey added an answer in Hydrogel:
    Which is the best hydrogel material for diabetic foot ulcer treatment?
    I read about application of hydrogels in wound healing. But we can use different materials for hydrogel, out of these materials which one will shows bet healing?
    Renee Cordrey · George Washington University

    Commercial hydrogels are typically glycerine-based, water-based, or a combination.  I doubt you'll find much literature comparing brands or types.  Personally, I prefer the glycerine-based ones since they don't dry out so easily and can stay in place longer, disrupting the wound less often for dressing changes and easing caregiver burden.

  • Russell Linscott added an answer in Antibodies:
    I am looking for an antibody of pax6 and Tbr2 that are not made in rabbit?

    I would like to make a double staining Pax6/Tbr2, but the antibodies for pax6 and Tbr2 that we have in the lab are both made in rabbit. Before I was using a mouse anti Pax6 but the manufacturer has stopped the production.

    Could you help, please?

    Russell Linscott · Independent Researcher

    We list a number of suppliers that offer mouse mAbs and non-rabbit pAbs vs. Pax6 and Tbr2 (EOMES). Just search here: http://www.linscottsdirectory.com/search/antibodies

    and contact the suppliers directly for more details. Good luck!

  • Abhijit Mitra added an answer in Phytogeography:
    How can I evaluate the effect of elevated atmospheric CO2 on the plant distribution pattern?

    I'm trying to access the effect of elevated CO2 on plant distribution but I didn't have any previous distribution data to compare. I'm much delighted to hear any suggestion from other researchers regarding this topic. Tqvm 

    Abhijit Mitra · University of Calcutta

    A long term data on carbon dioxide and AGB, BGB may give you some clues

  • How do you calculate power for given electrical system?

    Their is a voltage control device whose input side is connected to mains (in India voltage supply is 220V). The output side of the device is connected to wires of a pump (18W capacity). 

    Now voltage can be controlled to 10, 20, 30 ,40 , 50, or 220V using a voltage control device. How do you determine what power is delivered by the pump at those specific voltages?

    Any info is of great help.

    A.F. Saleh Alshandoli · The Faculty of Engeering, Bani-Wlid, Libya

    P = sqr(3)*I*V*Cos (phi)

  • Do you know of any case in which physicists accepted a basic theory based on a derivation from accepted theories, or its mathematical structure?

    Kuhn says leading physicists accepted Newton's theory of gravitation before astronomical measurements were accurate enough to decide the issue ["Structure of Scientific Revolutions" 1962]. Other than this aged example, is there any case in which physicists accepted a new or modified basic theory of physics based on a mathematical derivation from well-accepted theories, before direct empirical evidence was available? The Higgs boson and cosmic inflation have something of this flavor: these theories had substantial credibility before empirical evidence was available because they explained phenomena that were left unexplained by existing theories, but they were not fully accepted in the canon of physics.

    Of course, the law of gravitation without taking into account the recoil, i.e. the third law, is inconsistent.  The second law is F = ma, bzw F = Ma.  The frames of each mass are not Galilean, Newton's laws aren't valid in them.

  • How can I determine the bacterial strain ?

    Hello everyone,
    I isolated 23 bacterial isolates  from UTI samples. I determined  the species and subspecies name by technique available in my Lab, but I unable to   assign strain name. I do not know whether bacterial strain refer to number of bacterial isolate in my Lab or any thing else like use specific technique. Kindly I need your opinions and suggestions.

    Thank you  

    Brandon M. Bauer · Biolog, Inc.

    Biolog Inc. has a very easy system for Microbial identification with a database of over 2,500 species.  Please let me know if you have any questions.


  • Adam B Shapiro added an answer in Fluorescence:
    What's the equation for corrected AUC calculation of fluorescence spectrum? meaning? its importance?

    I calculated AUC of emission spectrum and i was asked to calculate the corrected AUC. i don't know why and how.

    Adam B Shapiro · AstraZeneca

    The experimentally measured emission spectrum needs to be corrected for the peculiarities of the spectrophotometer, which includes the transmissive properties of the monochromators, and the detector's sensitivity as a function of wavelength. Typically, the instrument manufacturer will supply a correction file, which consists of a set of multiplication factors for each wavelength. After applying that to your measured spectrum, you will have the true emission spectrum. In a fluorescence resonance energy transfer experiment, to calculate the Forster distance Ro you must measure the overlap integral J, the area under the overlapping curves of the normalized emission spectrum of the donor and the absorbance spectrum of the acceptor. You must use the corrected emission spectrum for this purpose.

  • Renee Cordrey added an answer in Pressure Ulcers:
    Does wound care affect informal caregivers?
    I am looking for any extra literature: theoretical, research or practice based, relating to the family, friends that care for someone with slow healing wounds
    Renee Cordrey · George Washington University

    Look at the research from Kiecolt-Glaser, Glaser, and their group.  They have done a lot of work on stress and acute wound healing, including a lot with caregivers for loved ones with Alzheimers (but not wound caregivers).  Also, here are some others:

    Pittman J. The chronic wound and the family. Ostomy Wound Manage. Feb 2003;49(2):38-46. 60.

    Snyder RJ. Venous leg ulcers in the elderly patient: associated stress, social support, and coping. Ostomy Wound Manage. Sep 2006;52(9):58-66, 68.

  • Who should I read for postmodern anthropology? Or applications of postmodernist theory to anthropology?

    Where will I find readings in anthropology which apply postmodern critical theory?

    David Charles Wright-Carr · Universidad de Guanajuato

    This article was just posted on Academia.edu, and I tracked down the original web source:

    Ortiz de Montellano, Bernard, “Post modern culturalism and scientific illiteracy,” in APS Physics (American Physical Society), vol. 7, no. 1, January 1998 (http://www.aps.org/publications/apsnews/199801/backpage.cfm, access: March 6, 2015).

  • Virginia Picanco added an answer in iPSC:
    Problems with iPSC transduction

    I am trying to do transduction with lentivirus to ipsc on mefs. However, I recieve an excelent transduction to mefs and zero transduction to my ipsc. Its look like the ipsc colonies have some defense mechanism.

    I put 100 moi of virus with GFP on first day that I passed my cells for 24h and I also tried to put 100 moi 2 days after passaging. both of the working but only for mefs cells and not for my ipsc.
    Do you have some protocols or explanation what I am doing wrong?
    Thank you,


    Virginia Picanco · University of São Paulo

    Hi Anna, we also have problems to generate our iPS cells. We use stemcca viruses and we use the MOI 2. The efficiency is very low. now we are using plasmids to generate iPS from blood cells, and it is working better. If you want I can send you this protocol.

    Good look,


  • How can I do qualitative and quantitative analysis using IMAGE ANALYZERS?

    Can anybody explain how to analyze bio analytical data qualitatively and quantitatively using image analyzers?

    David Glyn Roberts · University of Melbourne

    If you want an example of one qualitative analysis I suggest you have a look at Tarr & Thomas (2011) "Mapping Embodiment: methodologies for representing pain and injury" Qualitative Research 11(2): 141-157

  • Stasa Tumpa asked a question in Sodium Lactate:
    Disadvantages of activity stain ? Poor bands distinction when performing gel electrophores on lactate dehydrogenase form different tissue?

    The gel electrophoresis was performed using the 1% agarose, pH=8.6 on lactate dehydrogenase from heart and skeletal muscle samples. The results obtained were quite poor, no clear bands. I was wondering how could I explain this?

    Also I know what the advantages of activity stain are, but could you tell me what are possible disadvantages of  activity stain (the one used in this experiment was: 100mM sodium lactate 0.2% NAD 0.6% tetrazolium dye (MTT) 0.005% medola blue pH 7.5)

  • Is it possible to derive the constant & uniform velocity of light & the Lorentz transform without starting from the principle of relativity?
    Originally the Lorentz transform was developed to explain the Michelson-Morley experiment in terms of length contraction due to motion through an ether. Some work was done on how this might produce distortions of electromagnetic forces and interatomic bonds to produce length contraction. Einstein postulated a fully symmetric (i.e. relative) form with no preferred frame of reference, and gave a different derivation based on the principle of relativity, that the laws of physics including the velocity of light should be the same in all inertial frames. It is a pretty large assumption and gives no insight into mechanisms.

    In years of searching I've found only two papers that claim to derive something like the relativistic Lorentz (not the ether one) from more fundamental principles, one by Yilmaz using de Broglie waves which has received no follow up discussion that I can find, and one by Matthew Brown using pseudo-measurement interaction counting which is only on arXiv (and RG in his profile). Are there any others?

    Does it make any difference if relativity can be derived from some mechanism-like postulates? Does it have any implications for understanding things like spooky action at a distance (entanglement)? Or inertia/gravity?
    Hugo Alberto Fernández · National University of Technology

    Dear Halim & Charles, Shuler’s question is:
    Is it possible to derive the constant & uniform velocity of light & the Lorentz transform without starting from the principle of relativity?
    The answer to Shuler's question is
    Yes, it is possible, accepting that physical space-time is pseudo-Euclidean.

    Every physical theory requires at least one postulate and often admits several different treatments. The deepest formulation is one that has fewer postulates (Logunov formulation needs only one postulate).
    Anyway, depending on your target you may have preference for one particular formulation or another.

    With reference about behavior of nature, by which the phenomena are as they are because of the "symmetries" of space-time, we have a wonderful example that holds that conjecture; it is the Emmy Noether theorem, showing that Universal Principles of conservation are consequence (theorems) of space-time properties. The correspondence between conservation laws and symmetries is as follow:
    - Energy <--> Time uniformity
    - Momentum <--> Space homogeneity
    - Angular momentum <--> Space isotropy
    It is important to remark that such symmetries are present in Minkowski space and in the Galileo-Newton space-time, so the conservation laws are valid in both theoretical frames. However, In Minkowski space the conservation laws are directly obtained from space-time geometry, while in Galileo-Newton space-time it is necessary another assumption (Galileo transformations) because space and time have different separate metrics.
    In order to describe dynamical processes derived from geometrical properties of space-time, the mathematical space should contain space and time in its own metric. Otherwise there are not possibilities to have a correspondence between phenomenon and space-time geometry (and symmetries).
    The Galileo-Newton absolute space (Euclidean) and the absolute time are independent, they have different unrelated metrics, so none physical law which has (x,y,z,t) or derivatives, can be deduced from symmetries of space and/or time.

  • Ahmad Hussain added an answer in Higher Education:
    How do you deal with colleagues that try to hold you back and bring you down?
    While you try to do your work and "go the extra mile" in teaching and research, some of your colleagues try to hold you back and bring you down. This may be due to their complex of inferiority, unethical upbringing, jealousy, etc. How can you convince them that if you succeed in some endeavor, then the whole department/faculty/university succeeds? While you always try to be a good team player and try a constructive approach always keeping in mind how to get to a win-win situation, all the politics they do is a destructive practice where they only think about themselves and their personal benefits! How do you deal with this type of colleagues?
    Ahmad Hussain · King Abdulaziz University

    Dear Krishnan

    I liked your sentence "7 Smart Ways to Deal with Toxic People"

  • Adam B Shapiro added an answer in Folding:
    Flow Cytometry MFI: divide or subtract?

    Hello Flow people: I have a question about interpreting my results by Flow Cytometry.

    Let’s say I have a background level of staining of Isotype-FITC at 100 MFI units. Then, let’s say I have protein A-FITC, which stains at 20,000 MFI units, and Protein B-FITC which stains at 10,000 MFI units. Assume that the staining for A and B are of equivalent affinity and kinetics.

    To find the relative levels, do I divide numbers, like this:
    A/bkgd = 20,000/100 = 200; B/bkgd = 10,000/100 = 100; A-B = 200-100 = 100 unit difference, and A/B = 2.00 fold difference

    Or do I subtract numbers to quantify changes in protein levels, like this:
    A- bkgd: 20,000-100 = 19,900; B-bkgd = 10,000-100 = 9,900; A-B = 19,900 - 9,900 = 10,000 unit difference, and A/B = 2.01 fold difference

    Also, is there a reference for this?

    Adam B Shapiro · AstraZeneca

    I agree with Govinda. You should subtract the background.

    The only reason to divide by the background would be if you wanted to make a statement about the signal-to-background ratio, as a measure of the sensitivity of detection for each of the antibodies.

  • What is the energy density of the vacuum?

    John Archibald Wheeler said: “Empty space is not empty.” However, there are many different models of the energy content of the vacuum. One extreme position is that the only energy density present in the vacuum is dark energy which is about 6x10-10 J/m3. The standard model has 17 named particles and each particle has its own field which fills all of spacetime. For example, the Higgs field is one of these fields and the energy density of this field has been estimated at about 1046 J/m3. Quantum chromodynamics also requires energy density at least this high. Field theory has zero point energy where the vacuum is assumed to have harmonic oscillators with energy E = ½ ħω where all frequencies up to Planck frequency are represented. This implies Planck energy density equal to about 10113 J/m3. This is often assumed to be impossible, but the argument can be made that general relativity implies that spacetime has impedance equal to c3/G ≈ 4x1035 kg/s. This tremendously large impedance is consistent with the vacuum having Planck energy density. http://onlyspacetime.com/QM-Foundation.pdf  

     We do not interact directly with the energy of the vacuum, but something is giving the vacuum properties such as constants G, c, εo, µo, ħ, etc. Therefore, how do you view the energy density of the vacuum?

    Unfortunately, there are no real grounds for dark energy besides trying to patch up the big bang theory. Since the big bang theory has so many issues, more or less conflicting with a large amount of observational data, there’s simply no reason to rely on such assumptions. Over-reliance on confirmation rather than serious attempts at refutation is known as pseudoscience because it can lead to false conclusions. The facts are that the CMB does not perfectly fit big bang predictions, but instead that of a non-homogenous universe (smoothness, hemispherical power asymmetry, large-scale structure, alignments, ect.). Furthermore, angular-scales and volume element measurements fully support a static metric rather than one undergoing accelerated metric expansion; you can only have one or the other and these issues are far from being resolved in big bang frameworks (and no, I do not support tired light; only Doppler and gravitational redshift are needed for a fully consistent theory).


    Without considering the possibility that dark energy does not exist and that vacuum energy density could vary with underlying fields, many viable solutions are being excluded. Furthermore, most physicist are stuck on the assumption that event horizon or curvature singularities exist in nature when such hasn’t been proven (and will never result in a consistent quantum theory due to problems with renormalization), further impeding exploration into alternatives. QFT is perhaps the closest to properly describing vacuum energy density, but the problem is very open at this point.

  • Paul Koszarny added an answer in Geolocation:
    Do we need a new definition of fractals for big data? Or must fractals be based on power laws?

    So far definitions of fractals are mainly from mathematical point of view for the purpose of generating fractal sets or patterns, either strictly or statistically; see illustrations below (Figure 1 for strict fractals, while Figure 2 for statistical fractals; Fig. 4 for fractals emerged from big data):

    Big data are likely to show fractal because of the underlying heterogeneity and diversity. I re-defined fractal as a set or pattern in which the scaling pattern of far more small things than large ones recurs multiple times, at least twice with ht-index being 3. I show below how geographic forms or patterns generated from twitter geolocation data bear the same scaling property as the generative fractal snowflake.

    Jiang B. and Yin J. (2014), Ht-index for quantifying the fractal or scaling structure of geographic features, Annals of the Association of American Geographers, 104(3), 530–541, Preprint: http://arxiv.org/ftp/arxiv/papers/1305/1305.0883.pdf
    Jiang B. (2015), Head/tail breaks for visualization of city structure and dynamics, Cities, 43, 69-77, Preprint: http://arxiv.org/ftp/arxiv/papers/1501/1501.03046.pdf

    The new definition of fractals enables us to see the fractals emerged from big data. The answer to the question seems obvious. Yes, we need the new definition. BUT, some of my colleagues argued that the newly defined fractals are not fractal anymore, because they do not follow power laws.

    Paul Koszarny · Almamer

    Dear Arturo, fractals emerge from nonlinearities and feedback loops in open systems with a floating entropy. We cannot make an assumption that the energy is decreasing for some reason as the energy comes from the sun in natural systems. In financial systems the energy is in the form of capital inflow. Why do fractals emerge and not something else? It is a difficult question in fact. Assuming an exponential growth is taking place in a system, why it always ends somewhere and does not evolve to infinity? Take a fern leaf, one could imagine it growing more and more until we would not be able to discern it as a whole from the arising complexity. It never happens so. Chaotic systems (deterministic chaos) have the ability of creating self-organized structures and soon some chaotic borders emerge at some universal distances from the initial perturbation. If one knows the energy of the perturbation, one can calculate those borders before they emerge. The energy of perturbation is contained in the trigger. For example it the size of the trigger is 10, then the standard Feigenbaum border and a critical place is at 4.669 times 10=46.69. The catastrophic (exponential) expansion 14.208 yields 142.08 for the same trigger.  Nikkei225 crashed exactly to the 14.208 border in 2011 and bounced back from the invisible line. Fractals emergence is due to the existence of stretching, squeezing and folding forces present in the system. Topologically they cover all possible forces which names may remain completely opaque to us. Please note that squeezing forces and dissipative forces are not the same thing. Dissipative forces will always be there, squeezing forces may be locally absent. Fractals remain contained in their bounded phase space due to those forces mentioned above and also due to the spontaneous emergence of triggers in  opposite directions. So in nature we deal with complexities with a number of active triggers in opposite directions even when the interactions between the agents are quite simple. What we eventually  see is a beautiful balance of linearities and nonlinearities and the intermittance of order and chaos, simplicity and complexity which ensure an overall and structural stability. Fractals are tokens of structural stability, self-organization and well behaving holistic systems which once they have come into being, will strive to survive and fight for their existence by reorganizing themselves when they face new threats or feel more stressors.  What are those triggers? They may emerge as a pre-planned development (willed) or due to some randomness or both. Recall that randomness is our unknowledgable part of nature.


  • Nebi Caka added an answer in Resonator:
    What are the advantages and disadvantages of Stable versus unstable resonator?

    Laser with stable resonator creates the axial and traverse modes. The mode frequency is a function of mirror radii and the resonator length as well as  the effect of transverse modes. What about the laser properties using unstable resonator? Those are beam profile, bandwidth , spatial and temporal coherence...

    Which are the domain of applications for stable and unstable resonators?

    Nebi Caka · University of Prishtina

    The main advantages and disadvantages of unstable resonators versus stable resonators

    Advantages of Unstable Resonators

    • The mode volume is usually wider and controllable.
    • Transverse modes are easily discriminated.
    • All mirrors can be perfectly (100%) reflecting, that is particularly attractive in the infrared region, where metallic mirrors can be used.

    Disadvantages of Unstable Resonators

    • The output beam cross-section is in the form of a ring, i.e. has a dark hole at its center.
    • The beam has diffraction rings.
    • The laser is more sensitive to the cavity perturbations.
  • William Michael Taylor added an answer in Parrots:
    Does anyone know what is the success of Candidiasis treatment in parrots?

    I tried to find some information about Candidiasis skin infections in AGP and in these literatures they mention only crop and GI infection. Does anyone has some informations about skin infection because it is very peristent?

    William Michael Taylor · University of Guelph

    Candidal infections of the skin are very uncommon in Grey parrots on a good plane of nutrition and with a normal immune response. As others have noted is is highly opportunistic, yet in psittacines is rarely a cause of superficial dermatoses. certainly, treatment with systemic and topical fluconazole, and/or topical enniconazole should eliminate the Candida sp. Does this bird have a circoviral infection? This is a common cause of immunosuppression in Grey parrots.

  • Any advice on Fluorescent in situ hybridization in suspension (FISH-IS) with Locus- specific probes (LSI) ?

    I am struggling with detecting 17p deletion in Chronic lymphocytic leukemia (CLL) by FISH - IS using BAC ( bacterial artificial chromosome) with ImageStream X (Amnis), otherwise centro-mere probes works well.

    Many thanks,



    Cuc Hoang Do · Flinders University

    Thanks for your advice.

    I should be clearer. I have fixed CLL cells with Carnoy's solution( Methanol:Acid Acetic 3:1) before pepsin treatment but they 're still distorted. Could you please show me your protocol if possible? I am wondering the concentration of pepsin using? 

  • How can one resolve a linear programming optimization problem in MATLAB?

    While using MATLAB linear programming for optimization the following error occured

    ''One or more of the residuals, duality gap, or total relative error
    has grown 100000 times greater than its minimum value so far:
    the dual appears to be infeasible (and the primal unbounded).
    (The primal residual < TolFun=1.00e-008.)''

    I tried to change large scale algorithm to simplex algorithm using





     and then MATLAB showed an error

    LINPROG only accepts inputs of data type double.

    Please tell me where I am wrong?Or is there any other way to resolve the problem

    ''One or more of the residuals, duality gap, or total relative error
    has grown 100000 times greater than its minimum value so far:
    the dual appears to be infeasible (and the primal unbounded).
    (The primal residual < TolFun=1.00e-008.)''

    Mongi Ben Gaid · IFP Energies nouvelles

    I used the MATLAB interface for ILOG CPLEX during my PhD. It worked well for the problems I had to solve. May be you can try it.

  • Has Ajzen's Theory of Planned Behaviour (TPB) been used in HRM studies?

    I am working on a paper and require applications of the theory of planned behaviour, specifically those used in organizational settings or Human Resource Management contexts.

    Daryn Dyer · York University

    So far the feedback has been excellent, thank you. More sources welcome!