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  • Jacek A Koziel added an answer in Wastewater Treatment Plant:
    Can a PUF sampler be used for odour sample collection?

    At wastewater treatment plants (WWTPs), odor can be feel. The most common odor causing compounds at WWTPs are hydrogen sulfide, dimethly sulfied, dimethyl-disulfide, methyl mercaptan, ammonia, trimethyl amine, indole, skatole etc. The most common method to collect ambient air sample for odor analysis is lung sampler or seal canisters and followed by analysis on GC-MS or other instruments for quantification of individual odor causing compound. I wish to use PUF sampler for ambient air sampling, followed by solvent extraction and analysis on GC-MS. But, I am not able get any reference for the same. Can you suggest me some other methods for ambient air sampling?

    Jacek A Koziel · Iowa State University

    Hello Rishu,

    Some of the target compounds at WWTPs you listed can be challenging to quantify with a sorbent-based or whole air sampling followed by GC-MS.  I would recommend quantifying NH3 and H2S separately with (e.g.) some real-time, portable analyzers or colorimetric tubes (inexpensive, yet not very accurate). 

    Measurements of sulfur-containing VOCs can be confounded by catalytic conversion of methyl mercaptan into dimethyl disulfide and dimethyl trisulfide.  Complete deactivation of a sorbent or whole air canister, GC-injector, can minimize this effect.  Animes are also very unstable.  Some researchers had use N-specific and S-specific detectors to overcome separation and detection issues when complex air samples are used. 

    Indole and skatole (and phenolics such a p-cresol) can be quantified with (e.g.,) Tenax-type sorbent-based extractions (via sorbent tubes) and GC-MS.  Additional bonus is the capability to capture volatile fatty acids at the same time. 

    Good luck with your research. 

    Jacek

  • Romuald Pawluczyk added an answer in UV-Visible Spectroscopy:
    Can UV visible spectroscopy be used for determination of concentration of heavy metals?

    Can UV visible spectroscopy be used for determination of concentration of heavy metals ?

    Romuald Pawluczyk · P&P Optica

    Yes, using emission spectroscopy either by introduction of fine powder of tested substance into a plasma torch or by evaporating it with strong laser pulse (LIBS). Each of these materials possess some element specific set of emission spectral lines in UV/VIS spectral range sufficient for their identification and after careful calibration of the instrument also for concentration.

  • Arun Padhye added an answer in Phytophthora:
    What fungus is this?

    Can anyone identify this fungus, as it is growing along with my Phytophthora cultures. It is producing aerial mycelia whereas, Phytophthora is growing towards bottom of the media. I am growing on selective medium PARPH corn meal agar.

    Arun Padhye · Veermata Jijabai Technological Institute

    You go for subculturing. Prepare microculture on PDA/ Mycophil agar/Malt agar with added antibiotics or even Saborauds agar.                                                                 Once desired culture of your interest is available with you, try to maintened it in pure form adjusting the parameters such as pH, O-R potential and temperature in particular so as to increase its stability over longer time span.

  • Nisha S added an answer in Polymer Characterization:
    How to determine the DP value for Cellulose?

    Is any method other than GPC, SEC, fluidity to determine the DP value for Cellulose?

    Nisha S · Anna University, Chennai

    Is it possible to determine using Mass Spectroscopy technique?

  • R. Maheswar added an answer in Energy:
    Wireless Sensor Nework energy consumption matlab code based on event arrival

    Hi,

    I am doing research for highly energy efficient Wireless Sensor Network. May you please see the attchment file and rectify or add the required matlab coding for energy consumtion, like 1. Initial total energy of the network

    2. Total energy of any cluster 3. Residual energy of the networ/cluster. 4. Average energy of the network/cluster/noe. 5. Energy balance factor 

    Thanks .

    E-mail:ferdous@soc.ait.kyushu-u.ac.jp

    R. Maheswar · Sri Krishna College of Technology

    Seen ur code..pls correct the errors and send me... I will tell you what to do with calculations

  • Arunkumar Rengaraj added an answer in Column Chromatography:
    Crude enzyme has to be stored and what precautions should to be taken during the ammonium precipitation and column chromatography?

    ammonium sulphate precipitation and chromatography

    Arunkumar Rengaraj · Inha University

    For long term storing crude enzyme mixture ,u can use sorbital based stabilizer

  • Adam Erickson added an answer in Ecological Niche Modeling:
    Is there any online source for niche modelling of the plant species?

    I am working on Viscum and wish to go for niche modelling of the same now. If any body has any knowledge of any online open source which can be used for niche modelling of plant species, please inform 

    Adam Erickson · University of British Columbia - Vancouver

     Hi Harish,

    I think you will run into the classical tradeoff between model specificity and generalizability, as described in Levins (1966) "The strategy of model building in population biology," a seminal paper on the subject. It's important to understand that most models used today are fundamentally correlative multivariate models anologous to the Hutchinsonian niche (a static n-dimensional hypervolume). Machine learning (e.g., MaxEnt or Random Forests) is the most advanced purely statistical approach of modeling this n-dimensional space. While these models are highly generalizable due to their statistical nature, often requiring little to no parameterization, they lack the specificity of biological and ecological processes known to exist. Hence, there is the classical tradeoff.

    Process-based models, such as the Tree and Climate Assessment Germination and Establishment (TACA-GEM) model that I recently worked on with Craig Nitschke, offer an interesting alternative that I believe to be more biologically and ecologically sound. The catch is that these models often require not only greater model design effort, but ample parametric dimensions to maintain generalizability. Yet, as noted by Levins (1966), process-based models can improve modeling efficiency and reduce dimensionality while maintaining a higher level of specificity by focusing on the most salient processes. This balance is one of the most interesting and challenging things in ecological modeling. In general, I think even as machine learning continues to improve, process-based models offer more predictive power.

    I would focus on not only the factors, but also the processes, most important to Viscum distribution and abundance and try to put together a model using data for populations and conditions your area. I hope our publication may offer some insight into how this may be done, as we integrate phenology and regeneration processes to model changes to plant distribution. Although it appears very complex, the model started off much simpler and grew more complex over time with the addition of new sub-processes. I think you may find this approach to modeling the niche(s) of plant species quite interesting. For more general background reading, the works of Miguel Araujo are quite good.

    Cheers,
    Adam

  • Abel ogochukwu Egwu asked a question in Drafting:
    Please, i would really welcome someone helping me with a clue on seismic impact on tailing dams?

    i would love to work on tailing dams, i have to produce a paper on this topic as part of my unit assignments. a draft would be welcomed so as to enhance my research thanks. ABEL

  • Xu Feiyue added an answer in Protein Mass Spectrometry:
    Why do my MS sequencing results not match proteins?

    I cut the gel after the silver staining and sent it to be detected by MS. The results can predicate some proteins. But thesignals for all samples were not very high and protein score C.I % was zero. Almost all the  samples did not show protein matches. The detials can be detected in the attachment. Have someone met the similar questions and can you give me suggestion? Many thanks.

    Xu Feiyue · The Chinese University of Hong Kong

    Dear Jean,

    Sorry to reply you so late. Thanks for your suggestion. I will try to use other proteases. 

    Many thanks

    Feiyue

  • Mohan Kumar S asked a question in Isolation:
    May I Know how to isolate coprinopsis spp from dung?

    Hello researchers may I Know how to isolate coprinopsis spp from dung,from soil,and from spoiled vegetables.

  • Avneet Kumar added an answer in PID Control:
    What is PI controller offset problem?

    In hardware implementation of closed loop control of induction motor d axis and q axis current controller output value keeps on increasing due to offset problem. I have tried low pass filter technique for removing the offset error in voltage model of sensor less control scheme.But for solving this problem in the controller i didn't found any technique. My question is that, is this problem occurs in the controller or not? If yes please suggest the solution.

    Avneet Kumar · Indian Institute of Technology (Banaras Hindu University) Varanasi

     Dear Tzanev 

                      I already modeled total plant with the controller in the simulink nad that is working nicely. My controller value are Kp = 0.22 and Ki = 350 for %kHz PWM switching frequency. But on the other hand when i am going for real time implementation using D-space the term integrator is causing some kind of offset problem which is leading to the instability. I m not getting the solution for this problem.

  • Thoriq Tri Prabowo added an answer in Quantitative Research:
    How can I analyze two different research data measurement scale?

    How to analyze two different research data measurement scale? For example: I am in condition quantitative research, I found 2 variables. But the problem they have different indicators, the one maybe measure by likert scale (1, 2, 3, ...) and the other maybe measure by nominal scale (yes-no scale). So, in this case how to data analyze?

    Thoriq Tri Prabowo · Universitas Islam Negeri Sunan Kalijaga Yogyakarta

    Thank you Julia, it was very helpful :)

  • Penny Mary Fisher added an answer in Communication and Media:
    Why do cats get such a bad reputation in popular media and what are the ramifications for animal welfare outcomes?
    We are doing a study of the portrayal of cats in popular culture as background research for a project examining differing responses from stakeholders to issues of cat welfare compared with responses to other animal welfare issues. Cats and dogs are often presented as binary oppositions, with cats more commonly carrying negative connotations. Does this influence response to welfare issues in the real world?
    Penny Mary Fisher · Landcare Research

    I always wonder whether the degree of 'ownedness' ie. their dependence or relationship to people, of a cat (or dog) is a strong influence on how their welfare is perceived? would be interested if you end up addressing this aspect in your study

  • Lee Suetyee asked a question in Final year project:
    May i know which key is the best to identify the sea star?

    And if the samples are froze under -80c and will the thawing process degrades the DNA? I have about 30 samples of sea star and my study is to examine species diversity of asteroid using morphological and molecular data. This is my final year project. So, i would like to hear more from you. Thank you. 

    Thank you.

  • Tousif Ahmed asked a question in Laptop:
    Comsol and Intel Xeon Phi Coprocessor?

    I am using HP Zbook 15 G2 Workstation for Comsol simulations. Though ram on the laptop is quite fine, the processor is not up to the mark for comsol simulations. So, I was wondering if I can use Intel Xeon phi co-processor in my laptop using external express slot? Also, how to run simulations on the Xeon Phi Co-processor?

    Thanks in advance. :)

  • Randy Duckett added an answer in Nursing Education:
    How can we teach empathy to student nurses?

    I would like to get suggestions on what techniques, strategies or activities we as nurse educators can use to help develop empathy in student nurses. 

    Randy Duckett · East Carolina University

    This topic is very VERY close to my heart.  Empathy is something that you do not get taught.  You either have it, or you do not.  That being said, most people (excluding sociopaths) have some level of empathy -- problem being connecting to empathy.

    One of the best exercises I've found in fostering empathy as a nurse and professional and what not as I grow older is removing an impaction from my mother. 

    That activity in particular isn't going to be an activity relevant to the classroom.  PLEASE for the love of all teach your students which way the brief goes on.  However, here is what I can offer up to foster both humility and a sense of connectivity.

    The scenario of ultimate empathy.

    Each student wears an incontinent brief during a clinical or non-clinical.  The student is allowed to remain continent during the clinical but is told before hand, that the person in bed could be them, and that person could be waiting for someone else to change them until they mess themself. 

    It will change their world paradigm.  It did for me.  Perhaps it wasn't or isn't entirely ethical, but I came from a school with a 100% NCLEX pass rate for over 15 years and only the strong survived.  This was secondary to and not ECU which is listed as my alma mater.  ECU would never do this to any student.  I will not identify the school that did this to me. EVER.

  • Feng Shi added an answer in Laplace Transformation:
    Why the z-transform does not follow the same form as the Laplace transform?

    both Laplace and z-transform use the whole complex plane to move from time domain to complex exponential s-domain or z-domain, but z-transform has a different looking from the Laplace, my question is that why z-transform doesn't take the form, for example as the one in the attached image (an imagining one)

    Feng Shi · University of California, Los Angeles

    Thank you Danny, I really appreciated your answer.

  • Prabhat Kumar Upadhyay added an answer in Publications:
    How make to put my papers here?

    I have publications on PaM-Amazônica Newspaper and I would like to know how I make to put this publications here?

    Prabhat Kumar Upadhyay · GLA University

    add mauully from your profile and should show as dataset in your publication...

  • Peter T Breuer added an answer in Modal Logic:
    Can any known modal logic system be built from these 14 truth functions?

    The list is below with the decimal and binary labels.

    091 01.01.10.11 (◇p & ◇q) <---> (p ---> q)
    095 01.01.11.11 ◇p
    106 01.10.10.10 ◇(◇p <---> ~□q)
    111 01.10.11.11 ◇p <---> (q ---> p)
    123 01.11.10.11 q v (◇p & ~□p)
    127 01.11.11.11 ◇p v ◇q
    149 10.01.01.01 □(□~p <---> □~q)
    159 10.01.11.11 ~◇p <---> (~p & ~q)
    167 10.10.01.11 ◇p ---> (p & ◇q)
    175 10.10.11.11 ◇p ---> p
    183 10.11.01.11 ◇p ---> (◇p & ◇q )
    191 10.11.11.11 p <---> (◇p v ◇q)
    213 11.01.01.01 (□p v □q) v ( ~p & ~q)
    234 11.10.10.10 ~□p & ~□q

    Notice that the 2-tuple of "00" does not appear in these base functions.

    Peter T Breuer · Birmingham City University

     OK, well one answer is that you're not using classical propositional  logic. You've got a truth object with 4 elements, so I presume you're talking about the lattice

    .T

    /  \

    0  1

    \ /

    .F

    that is usually used to represent "open circuit/don't know" (F), signals (0, 1), and "the magic blue smoke/short circuit/contradiction" (T).

    If your propositional connectives (conjunction and disjunction) are monotonic with respect to this structure, then they will have the usual values on {0,1} and they MAY have 0&F=F&0=0, 1\/F=F\/1=1 and otherwise F as an argument gives F a result on {0,1,F}. In that case the propositional binary operators are not "flat at the bottom" - they do sometimes raise F as an argument a bit up the hierarchy. They should be flat at the top, however, with T ("contradiction") as a argument forcing T as a result. But you may have decided on the binary operators not being "flat on the top". You need to say! You need to tell whether your binary logical operators are strict (flat) or lazy (not flat). Computational implementations are usually lazy (not flat), but not symmetric either, with for example 0&F=0 but F&0=F. That's for sequential left-to-right computation. Parallel computation of both arguments simultaneously allows for symmetry 0&F=F&0=0. In these implementations F represents the non-terminating computation.

    The aim, whatever your specification, is always to have the binary operators "monotonic". Refining the arguments from F ("unknown") to 0 or 1 to T ("contradiction") ought to refine the outputs. "Flat" refers to the output being constant as one argument is held constant at F or T and the other is varied.

    It's good to get these binary operators to satisfy some sensible axioms beyond monotonicity, like distributivity, idempotence, etc. But you may not have done.

    The binary operators aren't going to be even Intuitionistic conjunction or disjunction however (minimum and maximum of two values respectively in that truth lattice), so you need to be extremely careful.

    In short, until you specify your propositional logic, never mind the modal logic, nobody can be expected to understand a word you say, and you should KNOW that, as a presumably intelligent, thinking, person!

    So the question is really why you aren't doing that ordinary thing that any human being would do, and explain what your symbols mean before going on to talk using them. The model for your propositional logic in the shape of the 4-valued truth lattice and the values taken by the binary logical operators on it is a minimal requirement for a successful conversation. It should not be that it has to be slowly "dragged out".

    Once you have the propositional logic sorted out, then one can ask what your modal operators mean. I suspect that a Kripke model is what you have in mind for them, with each world modelling the 4-valued propositional logic. But maybe not. Anyway, we certainly can't be expected to know until you explain!

  • Goutham Genomics added an answer in Glucosidases:
    What are various high content screening strategies for endoglucanase and glucosidase enzymes in bacillus or any other systems?

    I am constructing a library of mutant endoglucanase and glucosidase and compare their effect on enzyme activity. To screen these enzymes seperately through high content screening, what could be more reliable format.

    I have gone through few like use of CMC AGAR plate format in 96 well plate system and determine zone formation assay in 96 well plate, use of chromogenic conjugates and also use of FACS. But I wish to know your experiences and advice regarding :)

    Kindly attach any references with standard citations.

    Thanking you.

    Goutham Genomics · Madurai Kamaraj University

    Dear Deepti maam,

    Here I am looking for high content screening in 96 well plate format and determining extracellular efficiency within individual clones from a library. So have u tried the same CMC method in 96 well plate format.

  • Yulia A. Strekalova added an answer in Participation:
    What is meaningful participation?

    Since i have been carrying out a local level planning project to answer "what is meaningful participation" and how we could make planning process more inclusive.

    How could we measure it?

    Yulia A. Strekalova · University of Florida

    Great question! You might define it as a participatory behavior, showing up somewhere to volunteer for your local project or donating some (small) amount to support your project, or sharing the information about your project. I think you have many possibilities.

  • Prabhat Kumar Upadhyay added an answer in Acetazolamide:
    What is the ideal solvent for Acetazolamide for intravenous injection in rats?

    I need to inject Acetazolamide intravenously (single dose at 21 mg/kg) in anesthetised rats, while maintaining a pH at a non-harmful level. 

    For my desired concentration of 20mg/ml, it does not dissolve in saline or 0.1M NaOH, and 1M NaOH is too alkaline (pH 11), despite good solubility.

    If I were to choose an intermediate strength NaOH, can HCl be used to lower the pH?

    Thanks.

    Prabhat Kumar Upadhyay · GLA University

    NaOH is corrosive, always use very dilute solutions and use basic polar and nonpolar solvents for solubility and go to solution form then it will easily administered.....

  • Fadzli Ibrahim added an answer in Particle Size Distribution:
    How do I calculate particle size distribution function?

    Through my simulation work, there are results plotted for particle size (in diameter), particle mass fraction and also particle size distribution function (PSDF) but I'm not quite familiar with PSDF so I can't relate each of them. Is PSDF showing any relationship between size and mass fraction? How? Please help, thanks.

    Fadzli Ibrahim · Science and Technology Research Institute for Defence

     Dunxi Ju, thanks for the answer. So I just wondering why it is important to have an information of the particle mass fraction at each particle size (bin)? Is it not sufficient just to have an average size or mass for the whole domain? (p/s: sorry if this is a silly question...)

  • Lisa M. McEwen added an answer in Blood Sampling:
    Can I use EZ DNA Methylation-Direct kit for methylation studies in whole blood sample?

    Do I need to extract DNA from the whole blood first? or can I use the kit in whole blood with RBC?

    Lisa M. McEwen · University of British Columbia - Vancouver

    Yes, you can skip the DNA isolation step using that kit. However, volume required will depend on what technology you are using to assess your bisulfite converted DNA (450k, pyrosequencing, etc.)

    Indeed, cellular heterogeneity would need to be addressed, which you are hopefully aware of if you are analyzing whole blood...

    Jones, M. et al. 2015. Adjusting for Cell Type Composition in DNA Methylation Data Using a Regression-Based Approach. Methods Mol Biol. PMID: 26126446

  • Yulia A. Strekalova added an answer in Investors:
    Can anyone suggest me some paper/ literature reference for prediction/ forecasting the behaviour of Individuals?

    Human behaviour prediction elements: factors playing key role in decision making 

    Yulia A. Strekalova · University of Florida

    I would start with the classics, ELM or Chaiken's heuristic-systematic processing.

    Petty, R. E., & Cacioppo, J. T. (1986). The elaboration likelihood model of persuasion (pp. 1-24). Springer New York.

    Then, the prospect theory:

    Kahneman, D., & Tversky, A. (1979). Prospect theory: An analysis of decision under risk. Econometrica: Journal of the Econometric Society, 263-291.

    Then, possibly, fuzzy-trace theory or regulatory focus literature.

    Reyna, V. F., & Brainerd, C. J. (1991). Fuzzy‐trace theory and framing effects in choice: Gist extraction, truncation, and conversion. Journal of Behavioral Decision Making, 4(4), 249-262.

    Higgins, E. T. (1998). Promotion and prevention: Regulatory focus as a motivational principle. Advances in experimental social psychology, 30, 1-46.

    If your question goes beyond the classics, I think, you ought to narrow it to a topical or focused application. 

  • Himayatullah Khan asked a question in Kurtosis:
    How do we know which test to apply for testing normality? Different sources say different things regarding this.

    Statistical methods include diagnostic hypothesis tests for normality, and a rule of thumb that says a variable is reasonably close to normal if its skewness and kurtosis have values between –1.0 and +1.0. 

     If the sample size is larger than 50, we use the Kolmogorov-Smirnov test.  If the sample size were 50 or less, we would use the Shapiro-Wilk statistic instead.(Reference: www.utexas.edu/courses/.../AssumptionOfNormality_spring2006)

    For dataset small than 2000 elements, we use the Shapiro-Wilk test, otherwise, the Kolmogorov-Smirnov test is used. (Reference: . For dataset small than 2000 elements, we use the Shapiro-Wilk test, otherwise, the Kolmogorov-Smirnov test is used.)

  • Manthan Brahambhatt added an answer in Consumer Satisfaction:
    Can anyone suggest a good scale related to customer satisfaction in case of online shopping ( E-commerce)?

    I am trying to test the factors which influences consumers satisfaction in case of online shopping in Indian context. 

    Manthan Brahambhatt · St. Francis Institute of Technology

    hello ramendra pratap singh

    As per my Knowledge, I think you are asking for the scale to be used for customer satisfaction survey of a particular e-commerce websites. In that context, you can always use saaty scale or likert scale. with the help of those scale you can have data for your any particular context.

    Eg.:-

    The format of a typical five-level Likert item,  could be:

    Strongly disagree
    Disagree
    Neither agree nor disagree
    Agree
    Strongly agree

    so if your question stands like

    flipkart delivers the product on time as mentioned during the placement of order ? (delivery being one of the important factor for satisfaction in e-comm websites) -- because there is always a positive relation between service quality and customer satisfaction

    1.Strongly disagree
    2.Disagree
    3.Neither agree nor disagree
    4.Agree
    5.Strongly agree

    then according to click of radio buttons you input will be given to your particular database.

    In case if you dont want to use predefined scales you can use your own defined scale with properly stated hypothesis.

    I hope this may help you for your research

  • Waraphan Toniti added an answer in Tertiary Protein Structure:
    What are softwares to predict tertiary and quarternary protein structure from a sequence and how to validate it?

    I have the sequence of a protein and I want to predict the structure. Any suggestions

    Waraphan Toniti · Mahidol University

    You may try Phyre2 server or ModWeb for tertiary structure prediction.

    http://www.sbg.bio.ic.ac.uk/phyre2/html/page.cgi?id=index

    https://modbase.compbio.ucsf.edu/modweb/

  • Geng Ouyang added an answer in Quantum Mechanics:
    Are natural sciences reasonably effective in modern mathematics ?

    It is true that mathematics is reasonably effective in describing physical phenomena and to become a working lingua-franca of natural sciences. For that reason it is called the queen of sciences. No science, does well which is devoid of mathematics in its discourse. Therefore mathematics is reasonably effective in natural sciences.  

    Galileo Galilei (1564-1642) described the natural imperative to know mathematics in order to have an understanding of the universe we live in. His famous quote says it all “The universe cannot be read until we have learnt the language and become familiar with the characters in which it is written. It is written in mathematical language, and the letters are triangles, circles and other geometrical figures, without which means it is humanly impossible to comprehend a single word”.

    Eugene Wigner, in his 1960 well quoted short essay, “The unreasonable effectiveness of mathematics in the natural sciences”, treatise the beyond belief accomplishments mathematics displays in describing natural phenomena and working in natural sciences very effectively.

    I recently watched a public lecture by Robert Dikgraaf of the Institute of advanced studies at Princeton with his title of talk “The unreasonable effectiveness of quantum mechanics in modern mathematics” arguing the contribution quantum mechanics brings to the growth of mathematics. He quoted that Richard Feynman said “If mathematics disappears today, physics will be set back only by one week” but I will say, not set back by one week but it will collapse like a black hole.

    He himself, a mathematical physicist argued that mathematical rigor and physical intuition go in a kind of twins or conjoins of scientific discourse. A physicist with an extraordinary physical intuition will bear a physical result or proof of his intuitions only when verified by mathematical arguments or rigor. It is this physical intuition that emanates from quantum theory in particular that forces mathematics to stretches its  domain larger.

    It is known since the advent of science and the working of mathematics, that all sciences make tremendous contributions for enlargement and development of mathematics itself, as mathematics does for itself.  Biological sciences, neuroscience, weather, economic phenomena, physics and quantum processes are few such examples of sciences. 

    Do you agree with Feynman that a disappearance of mathematics is a one week setback to physics or a complete lose of power for it and turned it to state of existence of a black hole ?    

    Geng Ouyang · MinNan Normal University

    If we understand “how does mathematics come from?” and “what mathematics is?”, the answer is no doubt: natural sciences are reasonably effective in modern mathematics. There are many threads on these two questions.

  • Bryan Sigel added an answer in Butterflies:
    Some help researchers, on "the declining diversity of butterflies due to human activites?

    human activities that have escalated the problem