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  • Amanda Lo asked a question in Eye Color:
    Vermilion vs. Wildtype eye color in Drosophila adults?

    In Drosophila melanogaster (fruit flies), how significantly different is the vermilion eye color to the wildtype eye color? I was reading that vermilion has a brighter red pigment than the wildtype flies, but was wondering if vermilion and the wildtype red eye look significantly noticeable. In other words, how much brighter? and are the eye colors different to tell apart as the flies age? 

  • Any suggestions on thin layer chromatography and column chromatography?

    i had done tlc for my crude extract as it has been suggested by sv to check the compound and solvent system. i had found only 1 spot for my crude and the best solvent system. my desired pure compound is very polar (contain 3 hydroxyl group). 

    i understand after TLC, i had to do the CC using the best solvent system that i'd found out. But the problem is, the method for CC that i supposed to follow did not use any organic solvent, so i was confused here. Should i do the CC with the solvent system i'd found by TLC or just follow the method without using organic solvent

    Andria Agusta · Indonesian Institute of Sciences

    Okay. Jack already mention couple days ago. Sephadex A-25 is completely different than silica base TLC, it is an anion exchange stationary phase. You can't adjust your CC system using silica base TLC. You can perform your cc using a gradient system of methanol-water or ethanol-water start from 50% methanol/ethanol to 100 %. In my lab I used sephadex LH-20 with ethanol or methanol only to purify bisanthraquinone (possessing more than 3 hidroxy moeity). Other way, probably you can try to use normal phase silica with a solvent system chloroform-methanol-water (6:4:1). This solvent system is widely applied to separate and purify flavonoids. You can also put some amounts of mild acid in your system if your compound is stable enough.

  • Jerry Rhee added an answer in Philosophy:
    Philosophy and Science, what is the connection?
    The connection between science and philosophy has endured for thousands of years. In present-day conditions it has not only been preserved but is also growing substantially stronger. The scale of the scientific work and the social significance of research have acquired huge proportions. For example, philosophy and physics were at first organically interconnected, particularly in the work of Galileo, Descartes, Kepler, Newton, Lomonosov, Mendeleyev and Einstein, and generally in the work of all scientists with a broad outlook.

    At one time it was commonly held that philosophy was the science of sciences, their supreme ruler. Today physics is regarded as the queen of sciences. Both views contain a certain measure of truth. Physics with its tradition, the specific objects of study and vast range of exact methods of observation and experiment exerts an exceptionally fruitful influence on all or nearly all spheres of knowledge.
    Philosophy may be called the "science of sciences" probably in the sense that it is, in effect, the self-awareness of the sciences and the source from which all the sciences draw their world-view and methodological principles, which in the course of centuries have been honed down into concise forms.

    As a whole, philosophy and the sciences are equal partners assisting creative thought in its explorations to attain generalising truth. Philosophy does not replace the specialised sciences and does not command them, but it does arm them with general principles of theoretical thinking, with a method of cognition and world-view. In this sense scientific philosophy legitimately holds one of the key positions in the system of the sciences.


    Can philosophy develop by itself, without the support of science? Can science "work" without philosophy? Has science reached such a level of theoretical thought that it no longer needs philosophy? Or is the connection between philosophy and science so mutual that it is characterised by their ever deepening interaction?

    Lev, I use model-based reasoning in arguing for phi spiral abduction. 

    My point was that a revolution is labeled after the fact...kinda like "innovation".  In the process of becoming, innovation is labeled as either creative or crazy.  That is, the thing comes first, the name comes second. 

  • Joaquim Mª Rius Bartra added an answer in Industry:
    Computational Chemistry & Industry?

    Computational Chemistry has the basic application in academic field. Years ago there was the idea that the application in industry could help a lot to design new products but it seems that this idea didn't work.

    Nowadays, do you think if are there new possibilities? Do you think that a person with this acknowledgement may have value in the actual industry?

    Joaquim Mª Rius Bartra · Autonomous University of Barcelona

    Thank you for all your answers. In few month I will finish may degree. I am specializing in chemical industry, specially inorganic but a theme that fascinate me is computational chemistry and it is a thing that I would like to include  in my professional future but it seems that really it don't have future. Is generalized in my ambient that it is not useful unless for academic purpose.

  • Miss Biology asked a question in Fungi:
    How to read OD from minimal salt solution plus with oil and fungus.,for biodegradation of petroleum by using isolated fungi studies?

    The 10ml minimal salt solution + 2ml of petrol(oil) and selected fungi was put in the test tube and being incubated in the incubator shaker(120rpm) for 20 days with 28 degree celsius, and the reading of Optical Density will be taken in 5 days interval at wavelength 540nm..in order to know the degradation rate of oil using fungi. Is this the best way to study the biodegradation rate of oil using isolated fungi?

  • Any good reference for comprehensive numerical modeling of amorphous-crystalline ice irreversible phase transition in a cometary nucleus?

    Solving nonlinear time-dependent systems of PDEs.

  • Kelechi C Ofoleta added an answer in Java:
    Why String is immutable in java ?

    Why String is immutable in java ? Why String is a final class?

    Kelechi C Ofoleta · Victoria University of Wellington

    Writing or creating immutable classes in Java is becoming popular day by day, because of concurrency and multithreading advantages provided by immutable objects. Immutable objects offers several benefits over a conventional mutable object, especially while creating concurrent Java application. Immutable object not only guarantees safe publication of the object’s state, but also can be shared among other threads without any external synchronization.

    As for the question, Why String is immutable in Java? Why String is immutable in Java? Why String is a final class?

    It has been answered many times and I will not necessarily repeat it here, hence I have provided an existing reliable answer, courtesy of www.Kogonuso.com, an article that also appears at javarevisited.blogspot.co.nz/ below:

    Why String is Immutable

    The string is Immutable in Java because String objects are cached in String pool. Since cached String literal is shared between multiple client there is always a risk, where one client's action would affect all other clients. For example, if one client changes value of String "Test" to "TEST", all other client will also see that value as explained in first example. Since caching of String objects was important from performance reason this risk was avoided by making String class Immutable. At the same time, String was made final so that no one can compromise invariant of String class e.g. Immutability, Caching, hascode calculation etc by extending and overriding behaviors. Another reason of why String class is immutable could de due to HashMap. Since Strings are very popular as HashMap key, it's important for them to be immutable so that they can retrieve the value object which was stored in HashMap. Since HashMap works in the principle of hashing, which requires same hash value to function properly. Mutable String would produce two different hashcode at the time of insertion and retrieval if contents of String was modified after insertion, potentially losing the value object in map. If you are an Indian cricket fan, you may be able to correlate with my next sentence. The string is VVS Laxman of Java, i.e. very very special classy. I have not seen a single Java program which is written without using a String. That's why solid understanding of String is very important for a Java developer. Important and popularity of String as data type, transfer object and mediator has also make it popular on Java interviews. Why String is immutable in Java is one of the most frequently asked String Interview questions in Java, which starts with discussion of,  What is String, How String in Java is different than String in C and C++, and then shifted towards what is immutable object in Java , what are the benefits of immutable object, why do you use them and which scenarios should you use them. This question some time also asked as "Why String is final in Java". e

    Why String is Final

    As I said, there could be many possible answer of this question, and only designer of String class can answer it with confidence, I think following two reasons make a lot of sense on why String class is made Immutable or final in Java : 1) Imagine String pool facility without making string immutable , its not possible at all because in case of string pool one string object/literal e.g. "Test" has referenced by many reference variables , so if any one of them change the value others will be automatically gets affected i.e. lets say

    String A = "Test"
    String B = "Test"

    Now String B called "Test".toUpperCase() which change the same object into "TEST" , so A will also be "TEST" which is not desirable.

    2)String has been widely used as parameter for many Java classes e.g. for opening network connection, you can pass hostname and port number as string , you can pass database URL as string for opening database connection, you can open any file in Java by passing name of file as argument to File I/O classes.

    In case, if String is not immutable, this would lead serious security threat , I mean some one can access to any file for which he has authorization, and then can change the file name either deliberately or accidentally and gain access of those file. Because of immutability, you don't need to worry about those kind of threats. This reason also gel with, Why String is final in Java, by making java.lang.String final, Java designer ensured that no one overrides any behavior of String class.

    3)Since String is immutable it can safely shared between many threads ,which is very important for multithreaded programming and to avoid any synchronization issues in Java, Immutability also makes String instance thread-safe in Java, means you don't need to synchronize String operation externally. Another important point to note about String is memory leak caused by SubString, which is not a thread related issues but something to be aware of.

    4) Another reason of Why String is immutable in Java is to allow String to cache its hashcode , being immutable String in Java caches its hashcode, and do not calculate every time we call hashcode method of String, which makes it very fast as hashmap key to be used in hashmap in Java.  This one is also suggested by  Jaroslav Sedlacek in comments below. In short because String is immutable, no one can change its contents once created which guarantees hashCode of String to be same on multiple invocation.

    5) Another good reason why String is immutable in Java suggested by Dan Bergh Johnsson on comments is: The absolutely most important reason that String is immutable is that it is used by the class loading mechanism, and thus have profound and fundamental security aspects. Had String been mutable, a request to load "java.io.Writer" could have been changed to load "mil.vogoon.DiskErasingWriter"

    Security and String pool being a primary reason of making String immutable, I believe there could be some more very convincing reasons as well, Please post those reasons as comments and I will include those in this post. By the way, above reason holds good to answer, another Java interview questions "Why String is final in Java". Also to be immutable you have to be final, so that your subclass doesn't break immutability -

    See more at: http://www.kogonuso.com/2015/03/why-string-is-immutable-or-final-class.html#sthash.VgLU1mDY.dpuf

  • Paul R. Yarnold added an answer in E.G:
    Suppose am analyzing the data collected on "Factors influencing consumers to purchasing online; what will be the appropriate data analysis?

    My aim is to know  technique  for data analysis, e.g ANOVA,CHI-SQUARE or multivariate regression, MANOVA or ........... help me please

    Paul R. Yarnold · Optimal Data Analysis LLC

    Dear Galinoma,

    Without knowing the structure of the problem--the experimental design (outcome and predictor variables, number of observations, a priori hypotheses)--it is impossible to give you advice.

    However, this type of analytic issue is very common, and perhaps your project has the same general character as many other projects. If the outcome variable is whether or not the consumer purchased something online, then this is a binary outcome variable. If you have some combination of variables that can be used to predict the outcome--known as attributes, then you have a problem that is a classical discrimination problem. The most powerful (non)linear method for handling such problems is known as enumerated classification tree analysis (CTA):

    • http://odajournal.com/2013/09/19/62/

    The primary legacy statistical method used for such a design, logistic regression analysis, simply can't compare in terms of accuracy or parsimony, especially when there are categorical attributes having more than two levels:

    • http://odajournal.com/2013/11/11/univariate-and-multivariate-analysis-of-categorical-attributes-with-many-response-categories/

    There are many other articles on CTA in the open access eJournal, Optimal Data Analysis:

    • http://ODAJournal.com

    Many other articles using CTA have been published in other journals (see the Publications Tab at the ODA journal site), and the Gallery Tab presents some of the CTA models that have been published.

    You may be interested in a pair of books that provide an intuitive introduction to multivariable and multivariate legacy statistical methods, as well as worked examples. These books at widely available at academic libraries, and/or through inter-library loan:

    • Grimm, L.G., & Yarnold, P.R. (Eds.).  Reading and Understanding Multivariate Statistics.  Washington, D.C.: APA Books, 1995.
    • Grimm, L.G., & Yarnold, P.R. (Eds.).  Reading and Understanding More Multivariate Statistics.  Washington, D.C.: APA Books, 2000.
  • Mohamad Afifi added an answer in Air Flow:
    What is the design of orifice used to calculate diesel engine air flow rate?

    this orifice is used in calculating air flow rate

    Mohamad Afifi · Universiti Teknologi Malaysia

    Look for vthe dsign in BS :EN standard on Air Flow Measurement....you have vto minstall the orifice at the inlet of an air chamber.....that  will give least inteference to your air flow

  • Adam B Shapiro added an answer in Buffer:
    What are the most likely reasons for low efficiency of a co-immunoprecipitation?

    I have recently been trying to optimize co-immunoprecipitation in K562 cells. I have tried 6 different antibodies for my protein of interest (all compatible with IP) and am using Protein G-PLUS agarose beads (Santa Cruz) and following their recommended protocol (20ul of beads, 2ug of antibody). I have tried increasing antibody concentrations, increasing bead amount and am still not getting a very good efficiency (ususally lies between 2 and 20 %). I am using cyotosolic fractions in CHAPS buffer and have also tried the C buffer from C/N fractionation kit. What would people think is the most likely next step to try? Is it p[ossible that the beads themselves are the issue and I should try some others?

    Adam B Shapiro · AstraZeneca

    Low affinity could be the problem, either of the two proteins you are trying to co-immunoprecipitate or of the antibody for its ligand. If so, it might help to keep the solutions as concentrated as possible and minimize the number and volume of washes. Changing the salt concentration could also be helpful, either higher or lower, depending on the nature of the interaction (hydrophobic or ionic, respectively). You might even go so far as to try chemical crosslinking to keep the two proteins together. A disulfide-reversible crosslinker could be used to separate them at the end.

  • Soo-Jin Jeong added an answer in Orthogonalization:
    What are the best parameters to check mesh quality ?


    I am getting good orthogonality and skewness in Gambit, but fluent shows bad orthogonality up to 10^-4. But my simulation results are very good match with experimental data ! So what should i do ? discard the mesh or continue with it for further simulations. Also my y+ are and <1.


    Soo-Jin Jeong · Korea Automotive Technology Institute

    Orthogonality mainly affects diffusion error like false diffusion which is accumulated along downstream. If your mesh orthogonality in the region of bulk flow is little bit poor, it does not generate too much error by convection and diffusion. However, mesh quality including orthogonality is very important in the region of curvature and near wall. 

  • Van-Huy Nguyen added an answer in Photocatalysis:
    How does light intensity and wavelength, (UV light vs visible light) effects product yield for photocatalysis process?

    How can we relate the light source to the product yield? I found a few papers that briefly explains that UVC light emits higher power that visible light, thus product yield will decrease with increase in light wavelength. Is there any better and detailed explanation on this?

    Van-Huy Nguyen · National Taiwan University of Science and Technology

    Dear Khozema:
    In addition to the emitting higher power of UV-C, in compare with visible light; you may also can compare the effect of photon absorption based on the spectra of different lamps and/or filters. Since not all the light delivered to the photocatalyst can be absorbed, our recent work defined the normalized light utilization (NLU) to explain about this correlation.

  • Mayiji Nyikosa asked a question in Finance:
    Any Development Finance/Economics research topics?

    With particilar interest in Environmental Finance, Infrastructure Finance, Entrepreneurship, Unemployment, Regional Trade and Investments

  • Natalia S Duxbury asked a question in Aeronautics:
    Do you feel that enough appreciation was given to K. E. Tsiolkovsky as the founder of aeronautics?

    K. E. Tsiolkovsky as the founder of aeronautics.

  • Han Ping Fung added an answer in AMOS:
    For performance improvement and evaluation in SMEs which software has the most effect?

    I found several software for performance evaluation and improvement like SPSS, AMOS,ANOWA, SEM, T Test for single and Multivariate Etc. I want to choose my local region industries like in Madhya pradesh, India and will take various parameters for performance improvement then what should I do? please help me.

    Han Ping Fung · Hewlett-Packard

    It is good to know various software tools that can perform different / overlapped quantitative data analyses.  However, don't let the tools dictate how we conduct a research.  In quantitative research context, a research should be driven by the research problem, then research objective(s) or research question(s), conceptual framework / research model, hypotheses then research method.  E.g. if a research model consists of few Independent variables (IVs) that are individually & directly influencing SME's performance improvement, then SPSS multiple regressions can be used.  If your research objective is to comparing the performance improvement etc across different groups of SMEs, then SPSS ANOVA etc can be adopted.  If your research model is getting more complex e.g. consists of many IVs interconnected with arrowed-lines in different layers and point to one or more than one dependent variable (DV) then SEM like SPSS AMOS, SmartPLS etc can be used.  In summary, research problem dictate research model then dictate research method and lastly the statistical software tools that we should adopt.  Wishing you all the best.

  • Michael S Hofman added an answer in SPECT-CT:
    What is the PET/CT and SPECT/CT acquisition protocol for post-Y-90 radioembolisation imaging?

    Our centre using GE Discovery ST scanner with an 8-slice CT unit for PET/CT - 3D acquisition; and Philips Brightview XCT for SPECT/CT. Our images was grainy and full of scattered photon. 

  • Adam B Shapiro added an answer in Heat:
    How can I neglect heat of dilution from heat of reaction in Isothermal Titration Calorimetry?

    In my ITC run (Nano ITC, TA instruments), the heat of reaction is less than heat of dilution. For e.g. the heat of reaction for 1st and 2nd titrations was 4.17uJ and 6.23uJ respectively whereas heat of dilution were 135.7uJ and 142.4uJ for the same. Both protein and ligand were prepared in same buffer. How to neglect the heat of dilution from heat of reaction?

    Adam B Shapiro · AstraZeneca

    I don't know the answer from experience, but it occurs to me that the heat of dilution measurement may be different at the start of a titration than at the end because the dilution factor is greater at the beginning than at the end. If that is true, then a better way to subtract the heat of dilution is to do a blank titration. Unfortunately, the precision of the subtraction will be problematic if two large numbers are subtracted to obtain a small difference. To improve precision, you should do several replicates and subtract the averages.

  • What is the desired resolution of a protein crystal after heavy metal soaking?

    Hi all, I am a newbie on crystallography. Currently I am working on a protein which we had one set of data around 2.5 angstrom. My supervisor suggested me to do heavy metal soak to solve the phase problem. I am just wondering what is the desired resolution after heavy metal soak in order to solve the structure?

    Thanks in advance!

    Heng Zhang · The University of Waikato

    Hi Antonio, 

    Thank you very much for you brilliant explanation. Can you tell me more about anomalous resolution? I am not quite understand what it is. Do you have any recommended sources for me to read? 

  • How to plot p/p0 vs x/H in paraFOAM ?

    How to plot the non dimentional graph in paraFoam.

    Victor Hugo HIDALGO DIAZ · Tsinghua University

    Dear Pratik,

    Sometimes paraview shows problems to plot graphs than you explained because paraFoam is only a way to interpret foam results. So that, my advise is transform the openFOAM result to VTK format, which is a native format of paraview by using "foamToVTK", then you can get the plot that you want or you can also export the data to csv.

  • Adam B Shapiro added an answer in Plate Reader:
    With regards to FITC casein, what is the correlation between fluorescence and protein concentration?

    Hi guys. I have been having some inconsistencies  with the reading of the initial fluorescence value of FITC casein (ex 490 em 520) when I am using it at 1 mM. When I use 1 mM of the substrate, sometimes the plate reader gives me the initial fluorescence of 3000+, but sometimes it gives me 7000+. I was wondering if anyone of you have ever come across this problem, and is able to enlighten me with the reasons as to why could this be happening. Thanks.

    Adam B Shapiro · AstraZeneca

    If you are really using 1 mM FITC-casein, and there is at least one FITC fluorophore per casein molecule, then you will definitely observe the inner filter effect, in which the fluorescence intensity increases sub-linearly with increasing fluorophore concentration. As Dominque Liger pointed out, the suitable range of fluorophore concentration is low-nM to, at most, low-micromolar.

    However, this is probably not the explanation for the variability you are seeing if you are using a consistent concentration of FITC-casein. Plate reader-based measurements of fluorescence intensity are strongly influenced by the geometry of the solution - the volume in the well, the shape of the meniscus, the type of plate. Any change in the plate reader settings, especially gain and focal height, will also change the measured intensity.

    Finally, FITC is highly prone to photobleaching, permanent loss of fluorescence upon exposure to light. Two samples that were exposed to light differently could have different intensities because of photobleaching.

  • Is anyone familiar with a protein concentration method for western blotting?


    I'm using a new protocol for subcelular fractioning for rat striatum and frontal cortex. Unfortunately, I'm obtaining little protein in fractions (nuclear, sinaptosomal and non-sinaptosomal), especially in the striatum. I already used a pool of the cerebral regions but it's not enough.

    Thank you

    Inês Pita

    Christopher Bradley · Lattice Biologics, Inc.

    It's somewhat difficult to quantify protein that's been TCA-precipitated because most people go directly into SDS-loading buffer. TCA-precipitated pellets can be very difficult to solubilize. I would search around and see if there are alternative protocols where the TCA-precipitated pellet is solubilized in something that is compatible with a protein quantification assay later. There are detergent-compatible protein quantification assays, but in that case, make up SDS loading buffer without Coomassie blue (and maybe without reductant) for use in resolubilizing your pellet. Then add that stuff to your sample before loading onto a protein gel. Hope this helps...More later if I can dig up my old notes.

  • Dan Spanton asked a question in Drug Release:
    Would Cumulative drug release graph Ever show a decrease ? Figure 7 of the following paper says it can! ?

    Would Cumulative drug release graph show a decrease ? My understanding is that cumulative release should never go down simply because it is an addition process, so if no release then add zero, thus it will stay the same as previous level/time-point.. Figure 7 on the following paper shows a decrease in the cumulative drug release graph! Can anyone comment on this as is this even possible? and/or do the authores have an explanation for this ? "Preparation and Characterization of a Novel Smart Polymeric Hydrogel for Drug Delivery of Insulin " Link : http://bi.tbzmed.ac.ir/Portals/0/BI-2011-1-2/Jafari-BioImpacts-2011-1-2.pdf

  • Why am I getting two bands after PCR amplification of my aptamer sequence?

    I get two band in Agarose gel I also used PAGE too...my target band 100 bp but  other band that is unwanted is about 300 bp

    my reaction is :

    Buffer 2.5u

    dntp 1u  (10mM)

    Mg (50 mM) 0.4-.075u

    Forward and reverse 0.75-0.6u

    Taq polymerase 0.2u

    Tempelet 2-3.5 u

    I used gradient PCR 54-64 

    my programe

    94 - 5min

    denaturation 94-30 sec

    anneal(54-64) 30 sec

    extention 72-  30  sec

    final exten  72 - 5min

     I also change the cycle :35-30-25

    Vinayakumar reddy Gedi · Hanyang University

    I had similar problems when i used Taq polymerase. Not sure how, it works fine with Pfu polymerase for random aptamer library. Try with Pfu and also try with different template concentrations. 

  • Zouhair Hanani asked a question in E.G:
    Silver nanoparticles (AgNPs)/polymer matrix (e.g PCL)?

    Hello everybody!

    We all know that Silver nanoparticles (AgNPs) has an antibacterial proprieties. When added to a polymer matrix (e.g PCL), what's is the maximum percentage of this antibacterial charge (AgNPs), to have a better antibacterial properties ?

    Thank you!

  • Heba Huessin added an answer in Sample Size:
    How to calculate sample size using Altman's monogram?

    I know there are different methods to calculate sample size, but I need this one, please! 

    Heba Huessin · Cairo University

    Thanx all

  • Suggest a technique for purification of protein (150kDa) and it's PEGylated conjugates (appx. 170 to 200 kDa) other than Automated SEC- superdex 200?

    In my lab i am unable to separate it manually and donot have the facility for automated SEC. Is there any other effective technique like Ultrafiltration by which i can achieve desired narrow separation with less polydespersity. 

    Adam B Shapiro · AstraZeneca

    Ultrafiltration is unlikely to be useful for separating the forms of the protein. Hydrophobic interaction chromatography, such as with phenyl-Sepharose may be useful in this situation. I would think that PEGylation would have a substantial effect on the salt-dependent binding of the protein to the column. Another method that might work is ammonium sulfate fractionation, which might separate the forms on the basis of precipitating at different ammonium sulfate concentrations.

  • Tuan Tran added an answer in Silver Nanoparticles:
    What is the mechanism of sonoelectrochemical progress?

    Hi everyone!
    I have successfully synthesized silver nanoparticles by sonoelectrochemical methods. In my experiments, the positive electrode is made of silver, the negative electrode is made of platinum. Trisodium Citrate is used as the electrolyte solution. In the electrolysis process, a conventional ultrasonic cleaning tank was used to dislodge the silver nanoparticles from the negative electrode surface. The silver nanoparticles have mean size 22 nm.
    However, I do not understand the mechanism of sonoelectrochemical process.
    So can anyone suggest me the answers to the following questions?
    1. How much is the magnitude of the interaction force between the silver and platinum?
    2. What is the effect of Ultrasound? I only use conventional ultrasonic cleaning tank. I do not use ultrasonic horn.
    3. The growth of silver nanoparticles on the electrode surface occurs like?
    4. How to calculate the critical size of silver nanoparticles on the electrode surface?
    5. Do the silver nanoparticle still grow after be detachment from the negative electrode surface?
    Thanh you so much!

    Tuan Tran · University Of Transport Technology

     Thank mrs. Swapnali Dhanayat so much!

  • Javad Seif asked a question in Citations:
    How do you cite a Maintenance and Operations Manual?

    To what category (books, standards,...) does a manual of an equipment belong and how should it be cited?

  • Paul Louangrath added an answer in Time Series:
    Is there a difference between a discrete time series on a positive domain and temporal point process?

    I am pretty confused. Is a temporal point process of {t0, t1, ...,tN} is consider a time series? In my understanding a temporal point process is a subset of time series. Many articles e.g. "Time series, point processes, and hybrids* by David  Brillinge in 1995 seems to give a clear distinction between the two. Example of data such as a spike train which are consider a point process, can one describe it in term of a time series?

    Paul Louangrath · Bangkok University

    TIME: Assume that we conventionally denote time as t0, t1, ..., tn where t0 = start time and i + 1 subsequent periods with modulus of equidistance, i.e. hour, day, week, month, year, etc. These are NOT series in the context of "time series data." They are discrete time periods, just as 9:00 AM, 10:00 AM are discrete periods where one has an appointment at 9:00 AM would not show up at 10:00 AM because they are discrete (distinctive) different period. The periods t0, t1, ..., tn are "serial" in a sense that one comes after another in predictable fashion, but the term "series" does not carry the same meaning as in context of time series data set. Time by itself without a corresponding observable event is just called "period." An observable event with corresponding time without subsequent repetition cannot be called time series set. It is only a point in time-space.

    TIME SERIES: When event occurs at a particular time by which the observed event is accounted for with time period corresponding to it, i.e. GDP per year; wage per hour; heart beats per minutes---when there is an event occurrence express in frequency over time period, we call it "time series" data---hence, Xt0, Xt1, ... Xtn for observed value  X at period ti.

  • Does anyone know a functioning predictable Quantum Computer?

    latest Highlights:

    Andrew D. Greentree · RMIT University

    Great question and there are actually quite a few examples. @Remi's answer is actually rather good (not just in jest) because of course we can view all quantum systems as being quantum computers.  Although I'd hazard to say that the Universe doesn't count as being 'predictable' (at least not at the quantum level ;)).  More generally however, any chemical reaction or polarisation experiment is a quantum computation that IS (usually) predictable.

    Quantum key distribution via BB84 is an example of the operation of one-qubit quantum computers (used as required), and as we look at ever increasing complexity of quantum computer experiments (multi-qubit ion traps and even liquid-phase NMR) we are definitely seeing small-scale quantum computation.  D-Wave two (as has been mentioned) is still controversial, but I think that the consensus is moving towards this being a working quantum computer, albeit not a conventional circuit-driven quantum computer.

    But of course we don't want predictable quantum computers, at least not in the sense of being classically simulable.  Everything mentioned above can be solved classically.  It would appear to be one of complexity and we should be soon able to do computations that are not efficiently classically simulable.

    The other big frontier at the moment is boson sampling, which is a form of quantum computation (although not obviously a useful form) which it appears we will very soon be able to solve quantum mechanically and not classically.  Certainly we'll be in the non-classical regime much faster than we will with factorisation or Hamiltonian simulation.