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  • Masoud Ovissi added an answer in Trace Elements:
    Are there any books or articles about the basalt alteration in the ocean?

    I am willing to do some researches about the different kinds of alterations in the basalt in the ocean. And I want to know if there are some books or articles describing the changes of REE, isotope or major,trace elements during the alteration processes

    Masoud Ovissi

    Dear Chen,
    I think some of these papers can help you finding some useful data.

    Truly Yours,
    Masoud Ovissi

    + 6 more attachments

  • waseem wajih said mansour Mansour asked a question in Chemistry:
    What is catalytic cycle by nickle complexes for NH3 + 3C2H2

    catalytic chemistry

  • Eugene F Kislyakov added an answer in Graphene:
    Why the adiabatic Born–Oppenheimer approximation (BOA) is broken down in graphene?

    I want to know is the broken down of BOA in graphene has been solved or not yet,

    See the link


    what are the other cases where the BOA is also broken down in them and Why

    Eugene F Kislyakov

    Thank You for reference, Erkki. Unfortunately, it is not available for me. To my mind Sadeem (and I also) is interested mainly in software for quantum chemistry. Superconductivity, of course, is interesting, but it is somehow separate topic.

  • Robert Ose added an answer in Fluorescence:
    Is there any membrane-impermeable cell tracker (tracer) which shows fluorescence only inside the cell?

    I'm searching for a cell tracker/tracer which is non-fluorescent outside the cell and cannot cross cell membranes freely. Once the dye is brought inside the cell it should remain there and gain fluorescence.

    Has anyone worked with something like that?

    Thanks in advance

    Robert Ose


    Tank you for your answers.

    But my main problem still exists: I need a cell-impermeant dye which cannot passivly and freely cross membranes.

    When I m not mistaken, the depicted CellTracker Orange is able to cross membranes freely?

    Thanks again and kind regards

  • Ivan Balducci asked a question in Variance:
    The statistics components of variance is useful for what?

    I have read this sentence:

    "The most important statistics from a random effects model are the ‘components of variance’ which estimate the variance associated with each of these sources of variation influencing a measurement."

    Well ...Then, the statistics components of variance is useful for what?



  • Md. Sarwar Hossain added an answer in Human Security:
    How do i plan for finding out the relationship between disasters and human security?

    Actually i want to do a research on how disasters effect on human security? what can be the major solutions to protect human security issues regarding disasters ? 

    Please help me to explore some recommendation for me in this regard. Thanks in advance. :)

    Md. Sarwar Hossain

    After defining the human security and selecting the indicators, you can do some survey r use HIES 2010 to understand the effect. Then possibly you can use literature/ FGD with local people/ stakeholder consultation for the recommendation

    Or you can recommend based on your result from the survey data analysis 

  • Wenya li added an answer in Sheet Metal:
    What are the available techniques of removing cladding materials from metal sheet' surfaces?

    Apart from machining technique, is there any other method through which cladding material can be removed from the surface of metal sheets?

    Wenya li

    grounding with abrasive paper, or sandblasting

  • Elsa Pesca Figueiredo added an answer in Family Caregiving:
    Can you give some good references about Mutual Help Groups for Family Caregivers of People with Dementia?

    I'am interested in study mutual help groups for family caregivers of people with dementia and I need to have a better perspective of beneffits of this peer groups for mental health of family caregivers. Can you give some good references?

    Best regards

    Elsa Pesca Figueiredo

    Dear Margaret,

    I appreciate your personal testimony. Is precious and I'll take it in considerations in my research.

    My personal best regards,


  • Dr. Tajudeen Abdul Hameed added an answer in Bioscience:
    Why we all look different?????????
    Asalam O alikum Hi friends Please disscuss the reasons why we all human beings differe from each other, though we have almost similar genome at exon level and produces phenotypic differnces in all of you..?
    Dr. Tajudeen Abdul Hameed

    What makes us HUMAN --- is that very answer is found --- if then--- we all shall be different in every way and such is the real definition of survival of MANKIND till today. Diversity and differentiation among human have built, destroyed and formed and collapsed and so on,,,,,,,,,,,,,

  • Cate Louise Williams added an answer in cDNA:
    How long does cDNA last at room temperature?

    How long it lasts CDNA at room temperature?

    Cate Louise Williams

    cDNA is essentially the same as DNA, DNA is quite stable and can probably be left out of the fridge/freezer for up to 24 hours without any significant denaturation occurring. Freeze-thaw cycles should be minimal, and for short term storage (less than 8 hours say) use the fridge.

  • Ridha Djebali added an answer in Turbulence:
    Which turbulence model is best to predict reattachment length of flow over a step?

    I have few questions if any one can add to it:

    1. I want to run a simulation with experiments done in free surface water tunnel. Which model you think can predict good reattachment length.

    2. I am using turbulent length scale 6mm and turbulent intensity of 5%. If the reattachment length is not close which parameter should i adjust.

    3. I am using 0 pressure gauge as outlet boundary condition. However experiment was conducted in close recirculating water tunnel. Is it correct? or should i use outflow as boundary conditions.


    Looking forward to hear from you soon.

    Ridha Djebali

    1/ LES (SGS) models may be, in general,  the more useful and that I know in many case that K-w , k-eps and their hybrid models < LES < DNS models: '<' means less accurate but inversely for the CPU time, the DNS take much more.

    2/ You should, over the choice of the turbulence model, you may have more accurate results for Xr by streching the mesh in the boundary layers along all the bottom surface.

    3/ For the LES, there are dynamic models which are more accurate then the classic LES _ smagorinsky one.

    4/ LES is more useful for 3D problems and is "unsteady".

  • Miroslav Fišera added an answer in ICP-MS:
    How reliable is the direct spectrophotometric determination of ions (not colorimetric) in water samples and / or biological extracts?

    I need to measure some ions concentrations, like phosphate, sulphate, bicarbonate, calcium, magnesium, ammonium, potassium, sodium ... but generally literature has reported colorimetric methods by direct reaction and / or by complexing. The main disadvantage of these methods is the cost of many specific reagents and / or access to modern devices for more accurate spectrophotometric determinations such as ICP-MS and atomic absorption techniques.
    On the other hand I would be interested in non invasive methods that do not destroy the biological samples for furthers determinations.
    Who can help with articles, methodologies and/or bibliographic references?

    Thanks in advance for any collaboration!!!

    Miroslav Fišera

    Spectrophotometry is generally molecular spectrometry method, which we may measured (quantify) molecules present in the solution (their concentrations). Metalic ions and some anions are analogues of atoms, so we have to use methods of atomic spectrometry (AAS, OES and ICP-MS). If we wanted to determine ions by molecular spectroscopy methods we have to convert them to the appropriate molecules (reactions with specific reagents) and use their absorption in the relevant region of the spectrum. As a non-destructive method for measuring elements and ions could be used X-ray fluorescence spectrometry method with some limitations of this method.

  • David Smith added an answer in Protein Overexpression:
    Is 2.5 mg of total secreted proteins in 1 L of colture media a reasonable yield for yeast protein expression? If not, how can I increase it?

    Hello everyone,

    I'm trying to purify a recombinant protein overexpressed in yeast and secreted in the colture media, 1 L ultrafiltrated and concentrated to about 40 ml. I know that expression yield in yeast is lower than in bacteria, but I don't know how much it should be and I still have very low yield of both my protein and total secreted proteins. The Bradford assay gives values of about 60 microgr/ml in 50ml, that is about 2.5 mg protein total, while for my protein I can only use the enzymatic assay for now, and calculate the U/ml.

    Is 2.5 mg of total secreted proteins in 1 L of colture media a reasonable yield for yeast protein expression? If not, how can I increase it?

    Thank you so much, you are always really helpful to me :)

    David Smith

    In our lab we produce various proteins in a yeast expression system and some proteins have high production (20-40mg from 1 L), whereas others have low production (0.3-1mg from 1 L). For some of our proteins, it is a good result to get as high as 1 mg. In my personal experience, I have found it easier to produce low molecular weight proteins in high quantity, compared to higher molecular weight proteases that I tend to find give a lower yield.

    We are more interested in the purity of the protein, as the yeast culture can easily be scaled up to increase our yield.

    Provided your expressed protein is coming out very clean, then I would be happy with a 2.5mg/L yield, as like I say, if you needed more you can simply up scale.

    It also depends on the application of your protein. If you want to simply run something like a fluorogenic assay to generate some biochemical data or demonstrate protein products on a protein gel, then a yield of 2.5mg/L should be absolutely fine. Whereas if you're generating protein for vaccine trials, or for crystallography studies, then you will have to upscale your production.

    Although my response is quite anecdotal, I hope you find it useful nonetheless.

  • Elek Telek asked a question in Current - Voltage:
    Does anyone have an idea what kind of parameters/compounds can influence the current and voltage during Western Blot?

    I have performed several times Western blot but in this case the current does not go up around 25-30 mA even if I adjusted 300 V, however, I did everything as the same like last few times when the current went up around 25-30 mA, as we expected even at lower voltage. Despite I did everything as the same  don't know  what kind of compounds or parameters or something can influence the protein transfer to the membrane. I guess that if the current is low that means proteins can not transfer to the membrane quite well, isn't it?

    How could I gain better protein transformation on the membrane?

    Thank you in advance!

  • Ahmed Elazab added an answer in SIFT:
    Could any one suggest how to reduce the size of descriptor and key-point on sift?

    I am using the SIFT for extract the local feature. The size of the obtained feature and description is very high, i wanna compress it's size. Can you suggest me, how to compress the size of the obtained feature. Thank you!   

    Ahmed Elazab

    You may try to do feature selection for simplification and reducing the computational costs.

  • Ashok KR Pradhan added an answer in Spinel Structure:
    How can I find the lattice parameter from 2theta intensity data of a ferrite sample?

    Ferrites have inverse spinel structure. I am giving the datasheet in attachment.

    Ashok KR Pradhan

    thanks but how to get FWHM from origin ?

  • Tapan Chatterji added an answer in Ferromagnetic Materials:
    What is the order parameter for ferrotoroidic materials?

    As we know that materials having more than one order parameters are called multiferroics. For ferromagnetic materials it is "spontaneous magnetization". Like this what is the order parameter for ferrotoroidic materials.

    Tapan Chatterji

    Ferrotoroidic domain walls have been observed in LiCo(PO4)3 using second harmonic generation technique [8] and a symmetry classification of such domains has been given recently [9]. Spontaneous toroidal moments have been attributed to exist in the multiferroic phase of Ba2CoGe2O7 (BCG) [10] and may be related to theobserved unusual magnetoelectric effects [11, 12]. Single crystalline thin films of MnTiO3 with an ilmenite struc- ture also exhibit a ferrotoroidic structure [13]. Neutron polarimetry indicates that the magnetoelectric MnPS3 is a viable candidate for ferrotoroidicity [14]. The magnetic phase transition in BiFeO3 implies the appearance of a toroidal moment [15] Ab initio calculations suggest that the olivine material Li4MnFeCoNiP4O16 is possibly fer- rotoroidic [16].
    A sequence of possibly two ferrotoroidal phase transi- tions has been considered phenomenologically for Ni-Br boracites [17]. Another physical realization of toroidal or- der has been considered as an interacting system of discs with a triangle of spins on each disc [18]. Both charge and spin currents can lead to a toroidal state [19]. Recent observation of orbital currents in CuO through resonant x-ray diffraction provides a direct evidence of antiferro- toroidic ordering [20] Ferrotoroidic materials exhibit lin- ear magnetoelectric effect; in fact, the toroidic moment is related to an antisymmetric component of the mag- netoelectric tensor (αij ≠ αji). Moreover, the toroidic moment can be viewed as a quantum geometric phase [21]. Beyond the magnetoelectric applications toroidic materials can also act as novel metamaterials [22].

    Note that the references are listed in my answer before.

  • Huiqun Xu added an answer in Rheology:
    Do you know any studies about the thickness / areal extent / volume relationship of sandstone injectites?

    Do you know any studies about the thickness / areal extent / volume relationship of sandstone injectites? I wonder if anyone used analogies of big scale fracturing processes to map injectite geometries and host rock / sand rheology.

    Huiqun Xu

    About fluid unit? You can use seismic attributes. I am now working on the carbonate fluid unit. Attached paper maybe help you.

  • Samran Naveed added an answer in Genetic Algorithm:
    Any ideas about SQLI Detection with Genetic algorithms?

    I Need ideas about the following :

    HOW we can apply genetic algorithm (GA) on web application vulnerabilities detection ? (what do you think about this ) 
    ideas about sql injection detection on web application..
    could we combine decision tree with genetic algorithm ? and how ?

    Samran Naveed

    did you find any solution of your problem???

  • Ehsan Nozad added an answer in Xanthine:
    Did anyone try (and succeed) to encapsulate xanthines into nanoparticles? Can't obtain appreciable entrapment efficiencies, any idea why?

    I have been trying to encapsulate caffeine within nanoparticles but, so far, without success. I tried double emulsion technique for SLN and ionic gelation for chitosan and for alginate nanoparticles. I am pretty sure that nanoparticles have appropriate size and morphology since I have already performed SEM and DLS analysis but, somehow, entrapment efficiency of caffeine is null! Does anybody have any suggestion? Thank you very much!

    Ehsan Nozad

    Why don't you use an in-situ method?

  • Diego García-Gusano added an answer in Climate Change:
    Can a “green tax” be an incentive to reduce pollution in your country?
    “Green taxes” (also called "environmental taxes" or "pollution taxes" or “eco taxes”) are excise taxes on environmental pollutants or on goods whose use produces such pollutants. “Green taxes” are meant to improve the environment or reduce the negative impact on the environment or create an environmentally sustainable environment. “Green taxes” are a kind of economic instruments to address environmental problems. It is generally believe that “green taxes” will reduce environmental harm in the least costly manner, by encouraging changes in behaviour by firms, organisations, communities and households and individuals etc. Taxes on pollution provide clear incentives to polluters to reduce emissions and seek out cleaner and sustainable alternatives.

    One “green tax” that has recently gained favour is a carbon tax. Australia introduced carbon tax (July 2012), which is an excise levy on the carbon-based content of fossil fuels (coal, petroleum, gas) as a means of reducing greenhouse gas emissions that contribute to global warming and climate change. The carbon tax may encourage development and use of clean energy sources in Australia (renewable or green energy such as wind, hydro, and solar). India and Japan has also introduced carbon tax. In Europe, a number of countries have imposed energy taxes or energy taxes based partly on carbon content. There is apparently no “green tax” in the USA; however “green tax” supporter often cite the gasoline tax as a “green tax”. Many European countries have used pollution taxes imposing taxes on emissions of common air pollutants such as sulfur dioxide and nitrogen oxides. To combat the negative environmental effects, several states in India (Maharashtra, Andhra Pradesh, Himachal Pradesh, and Karnataka- August 2010) have implemented/going to implement a new “green tax” to fight pollution from old vehicles (commercial vehicles over 8 years old and private vehicles over 15 years old) and creating better public transportation. Very recently, Bangladesh imposed green tax (June 2014) to force polluting factories (principally tanneries) to pay extra levies to clean up the country's increasingly dirty rivers and reducing impacts on the aquatic environment.

    Everyone may not agree with “green taxes” however, “green taxes” can be seen as an incentive to lessen environmental burden and preserve the environment. The revenues generated by “green taxes” can also be used for other environmental preservation projects or to cut other taxes. Nevertheless, everyone for sure would like to see an environmentally sustainable future and a healthy natural and living environment in their country.

    Question: Can a “green tax” be an incentive to reduce pollution in your country?
    Diego García-Gusano

    Dear Golam,

    We carried out an analysis using an energy optimisation model at country level (Spain) considering taxes on pollutants and ceilings derived from European policies. This could be helpful:



    • Source
      [Show abstract] [Hide abstract]
      ABSTRACT: Even though significant NOx and SO2 emissions reductions have been observed in Spain during last decade, there is a strong commitment to keep reducing the levels of pollution in order to improve air quality standards. This work has been carried out to ease the lack of National Emission Ceilings Directive (NECD) assessments at country level. The Spanish case has been used as illustrative of the European Union. The evolution of NOx and SO2 emissions has been analysed in depth using the TIMES-Spain energy optimisation model. The work has been structured into three parts. First, the implementation of the NECD and the consequences both on the evolution of NOx and SO2 emissions, and the electricity production mix; second, taxation on these pollutants has been modelled and discussed; and finally, the proposed “2013 EU Clean Air Package” ceilings to update NECD have been assessed. Results showed that meeting NECD targets would involve a high contribution of renewable sources to the electricity system, mainly wind and solar. In addition, NOx and SO2 taxation has been assessed. Results showed that taxes on pollutants led to lower emissions than using NECD. Hence, current ceilings are not strict enough to internalise all the environmental damages associated to those pollutants. In consequence, the suitability of the NECD has been discussed by means of the new ceilings included in the EU Clean Air Policy Package. Results showed that proposed reductions are insufficient to compensate the environmental damages especially in the short term.
      Clean Technologies and Environmental Policy 02/2015; 17(7):1997-2011. DOI:10.1007/s10098-015-0923-z
  • Andrea Paz Donoso Youlton added an answer in Diagnostic Methods:
    How can I get rid of non-specific amplification in a LAMP assay?
    I am trying to develop a LAMP assay for a fungal plant pathogen using HNB as the indicator. However, I am getting amplification even in negative controls without any DNA template added. I have changed reagents and rooms where I set up the assay, varied reagent concentrations and also checked all the reagents for contamination. I have also used different primer sets (all HPLC purified) for the LAMP assay but I still get this non-specific amplification in the negative controls. Is there anything else that I am supposed to look out for to prevent non-specific amplification in a LAMP assay?
    Andrea Paz Donoso Youlton

    Hi guys! Finally in my case i think it was a pair of primers that got contaminated so i just ordered new ones and now it has been working perfectly :). Rosa! yes I have been using higher concentrations of MgSO4 at it gets more violet .. also these days i have been using MgCl instead of MgSO4 and i think the colours look much better or easier to differentiate. Hey.. just realize you are in cambridge, I will be there monday and tuesday next week... any chance to meet you or visit your lab?? 

    Best regards 


  • Nurbol Mendaliyev asked a question in Laboratory Equipment:
    Can anybody help me with methods to evaluate downtime of clinical laboratory equipment and reagents?

    I going to evaluate rational using of laboratory equipment and reagents

  • Lluc Canals Casals added an answer in Battery:
    Why is there an increase in terminal voltage of battery in every new cycle of profile while the same current is applied?

    I am currently working on Flooded battery (maintenance free) . I applied a current profile on the battery in which its SOC moves from 50 % to 80 % SOC range in every cycle. Its a constant profile for 440 hours. But in every new cycle terminal voltage is increasing ( or we can say expanding in both upper and lower side ). Also if we notice the OCV after 30 mints of resting , it is also increasing in every new cycle which means this issue is not because of increase in internal impedance of battery as effect of internal impedance vanishes in 3 to 5 minutes. Increase of OCV is also shown in attached figure.Now i need to estimate the SOC of this profile. As the current is same in every cycle but OCV and terminal voltage is increasing , so SOC estimation is different for every next cycle while it should be same as current is same. I would be really thankful if someone help me by telling the reason of this phenomenon. 

    P.S. in the current graph , positive current means discharging and negative current means charging. Also capacity of battery is 90 Ah and 4.5A current pulses are used for 1 hour with 30 mints resting between each pulse. I am using a Bipolar power supply for applying current.

    + 3 more attachments

    Lluc Canals Casals

    If you are applying always the same amount of current it may occur that the battery capacity is fading. Batteries degrade with each cycle a little bit. If you charge 10 Ah in a new battery that has 20 Ah you would increase the SOC by a 50%. However, as battery cycles, the capacity gets lower and lower, so in the end, if the State of health is about a 75% you'll have a 15Ah of capacity and then the 10Ah charged would represent a 75% SOC increase. From the images, wheat I think is that each time you have less and less capacity in the battery, so every each cycle it increases a little bit more.

    What surprises me is the 16V max stabilisation. Is there a top voltage limit somewhere? For what I see, when the voltage reached this maximum, it is the minimum voltage that gets lower and lower at each discharge cycle. It may be the same thing, the battery ageing.

    It is not easy to contorl SOC in batteries :)


  • Sherlin Prem Nishold Selvaraj asked a question in Waves:
    What is the transfer function used to find wave height (amplitude) from wave spectrum ?
    • How to find wave height from amplitude spectrum or from FFT Data.
  • Robin Edward Jarvis added an answer in Agricultural Marketing:
    Which mathematical tools are suitable for modelling intra-community economic production flows over several periods?

    Which mathematical tools/approaches would be useful, or have been found to be useful, in modelling a 'manual agricultural' market economy amongst a closed group of ten to fifty households totalling up to 500 individuals in which a range of tools, crops and infrastructural facilities might be produced, maintained and exchanged across any desired number of periods and in which arbitrary individual propensities for each behaviour type of each individual can be expressed as temporal vectors, as can externalities such as climate, soil fertility, erosion and arrivals of itinerant sellers of externally produced trade goods?

    My background suggests to me that Tensor Calculus is the point at which one should start looking for the means with which to achieve this.  I suspect that the application of such tools to modelling the 'fluid' economic behaviour of social groups is not at an advanced stage of development. Has anybody any information or suggestions?  Are 'game avatars' likely to be a fruitful source of useful algorithms?  Thank you for any assistance or guidance...

    Robin Edward Jarvis

    Dear Vanda,

    My degree, admittedly only at BA level, is one of Econometrics with specialisation in multivariate correlation and I-O Analysis using matrix algebra and linear programming.  I find that although these techniques are suited to identifying and exploiting correlations between time series of data points so as to provide a descriptive analysis of 'state' snapshots along a time line.

    I did not make myself very clear in my question for the sake of brevity.  The need is, in fact complex.  I do not wish to only discover significant correlations by building a matrix of independent equations.  This is part of the preparatory work which would be necessary, it is true.  My goal is to build a modelling system which is essentially a simulation exercise. One which can follow the interactions of a set of independent agents which are themselves described by sets of interrelated behavioural functions the output of which at one point in time feeds into the next.

    The difficulty is to stop short of designing it as a 'hard problem' which cannot be practicably computed, but sufficiently complex that it can be realistic enough to have useful output.  And to be a system of computing that is sufficiently general that it can be applied across sets of interrelated groups of sub-problems so that the 'hard problem' difficulty can be avoided as the problem scope is scaled to the real world need.  I might also add that I am a real world computer system engineer and analyst.  I can see that this task is as much one of mathematical tools as it of computational process design.  But it needs the skills and knowledge of mathematical experts working together with subject theorists to design a pragmatic approach.

    The tool set you mention does not seem to me to be capable of providing a suitable mathematical framework for modelling multiple interacting 'processes' which are taking place between multiple agents with potentially independent goals along a time line.  Such that the inter-agent interactions that are effected in between one 'point of state' and the next are not a finite set but can themselves be subject to the effects generated by point values contained in multiple 'time series of externalities', each point of which  may have a different resultant level of 'effect' upon the 'state' value established for each next 'point of state' of any of the behaviour functions of each individual agent.  The coefficients in these agent behaviour functions would indeed most likely be determined by multivariate correlation analyses.  However, the particular coefficient value applied to a particular B-function of a particular agent would be allocated according to a desired distribution across the agents from specific coefficient values drawn from sampling the set of values representative of the probability curve characteristic of the 'best value' estimate for the coefficient which the behavioural correlation analysis stage has produced.

    I don't know if that is clear, or helpful to you.  Israr knows too well how convoluted my thinking can get!

    Best regards,


  • Debra Sharon Ferdinand added an answer in Soft Skills:
    How can we inculcate better communications skills in ICT graduates ?

    ICT professionals need good communication skills especially if they are interfacing with customers. However, with increasing need for more technical skills, there are less and less soft skills in ICT programmes. Please share your experiences.

    Debra Sharon Ferdinand


    Perhaps communication skills can be incorporated into the Customer Service or Marketing aspect of the course in which they would have to deal with customer complaints or sell computer products.

    Many thanks,


  • Shyam Moghe added an answer in Cockroaches:
    How can we control insects in children hospitals that are a sensitive group?

    I would like to know what is the safe method to control insects?

    what is the best poison that can be used to control cockroach?

    what methods use in developed countries to control cockroaches in children hospitals?

    Shyam Moghe

    Hi Farideh ,

    1. Correct identification of insect is very important as the control strategy depends upon the habit & habitat, that differs from  differs insect to insect. 
    2. In current scenario, Fipronil based cockroach baits are proving quite effective since it has a cascading effect. However only use of any poison would not  help in a sustainable control. This must be carried out by other preventive measures like Sanitation, Exclusion and Monitoring
    3. Pheromone traps with Sex Pheromone or Aggregation pheromone or Food based attractants are available and all of them are Non-toxic, odorless & hence safe to use in conjunction with preventive measures for long term pest free situation.in any   Pediatric Hospitals.