ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.
Browse by research topic to find out what others in your field are discussing.
- How can I calculate SD from a mean sample, range, N?
I'm doing meta-analysis in which a paper is reporting outcomes as a mean, range. Instead, I need to calculate the SD to be able to pool the effect in the meta-analysis model.
Yes agree with Klaus. I also cant see how you can go from range to SD, except if you have multiple samples with ranges reported then maybe you can construct an SD, but with one mean and range reported you cant. SD is variance including all the data so from three points (range and the mean) I cant see how you can approximate SD. Cheers.Following
- How achieve the best balance between teaching and research?
Academic life consist of two main components: teaching and research. If you a MSc or PhD student it is also has element of learning the courses. Can you recommend, how correctly divide time in order to save balance between each of these parts? Thank you in advance!
I get less lesson for teaching cos i m still a PhD student. So, outside the course hours, i study and research.Following
- As natural polymers, are fucoidan or chitosan are suitable for nanoencapsulation?
Nanocapsules are usually made with polymers such as PCL and PLA.
I'm new with these type of research and several works do nanoencapsulation with synthetic polymers such as PLA or PCL.
As a natural polymer, why not use chitosan or fucoidan to nanocapsulate? Several works do the concomitant nanoencapsulation (PLA + Chitosan), but not chitosan alone. Why?Following
- Is there anyone that has ever been dealing with "Spatial Behavior" in the context of vernacular settlement?
Spatial behavior research has been frequently used in the context of modern settlement, is there any significant difference between research on both context thank you ...
There is a large environment-behavior literature on spatial behavior, including material on vernacular lifeworlds. One of the most fruitful venues is the work in space syntax. A good bibliography to begin with is available at:
- Who is studying the equivalence between inertial mass and gravitational mass?
In one of our usual daily round table discussions at the Coaltso team we had glimpsed the solution to the problem of equivalence between the inertial mass and the gravitational mass regarding the existence of a physical experiment which can be used to distinguish them.
We think that this problem has a shortcut path. We hope for interested collaboratorsto join us.
This paper solved all the problems in physics regarded to quantization of gravitational The Quantization of General Relativity: Photon Mediates Gravitation http://dx.doi.org/10.14299/ijser.2014.10.002Following
- Any simple tool to use Indoor Air Pollution Level?
Any simple tool to measure Indoor Air Pollution Level?
Indoor pollution will be easily characterised by using passive samplers. They do not require electric power so they rea silent and veryu effective for averaging concentration levels over extended periods of timeFollowing
- Which are the best long term passive sampler methods for outdoor air pollutants (Gaseous & PM)?
We need to monitor air quality in term of SOX, NOX, PM2.5, PM10 and total VOCs pollutants for 2 years with seasonal resolution.In your opinion what is the best feasible option for passive monitoring seasonal concentration (3 month continuous measurement) of SOX, NOX, PM2.5, PM10 and total VOCs?
Personally, I published several papers concerning with the use of passive samplers in atmospheric monitoring. Our best results have been achieved with passive samplers developed at CNR. They are able to monitor ambient pollutants over extended period of time having good reproducibility and time consistency. They have been developed for NO, NO2, NOx, Ozone, SO2, H2S, H-CHO, BTX and VOC. Sampling is very simple and analysis is also easy to perform. I will be pleased (firstname.lastname@example.org) to provide you with more info.
For particulate matter, I would suggest the gravimetric method by sampling with small, yet effective, filter samplers equipped with PM10 or PM2,5 cut size inlets.Following
- Can you recommend me universities in the new EU member states that deal with the influence of low-dose on cells?
It means mutations, genetic damage, epidemiology, or something related to radiation protection research and risk of stochastic effects at low doses. After the Černobil accident we know the dependence of stochastic effect on high-dose exposure. But nowadays, there is a new subject - can we experimentally prove a dependence in the range of low-dosage?
Dear Eva. You can contact any of these institutions withitn the EU. All of them have some research activities in the effects of low dose.
STUK—Radiation and Nuclear Safety Authority, PO Box 14, 00881 Helsinki, Finland
2 Queen’s University of Belfast, University Road, Belfast BT7 1NN, UK
3 Helmholtz Zentrum M¨unchen, Ingolstaedter Landstraße 1, 85764 Neuherberg, Germany
4 Stockholm University, Centre for Radiation Protection Research, Universitetsvaegen 10, 10691 Stockholm, Sweden
5 Bundesamt f¨ur Strahlenschutz (BfS), Willy-Brandt Straße 5, 38226 Salzgitter, Germany
6 CEA—Commissariat `a l’´energie atomique et aux ´energies alternatives, Bˆatiment Le Ponant D, 25, rue Leblanc, Paris, France
7 IRSN—Institut de Radioprotection et de Sˆuret´e Nucl´eaire, Avenue de la Division Leclerc 31, 92260, Fontenay aux Roses, France
8 SCK-CEN—Studiecentrum voor Kernenergie, Boeretang 200, BE-2400 Mol, Belgium
9 PTB—Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig, Germany.
Perhaps they can provide you with the information that you are asking for.Following
- Could mushrooms survive in the wild on animal stools?
I have found 2 mushrooms in Makkah, Saudi Arabia. I was very astonished to see these mushrooms in very poor soil! After analyzing the habitat, I have found the high rate of camel stools in this area where these mushrooms are growing. Could the mushrooms survive on animal stools?
Please, could anybody identify these mushrooms?
I would like to thank all contributors,
for Dr Anish Joseph: Makkah is one of the hottest places in the world, the temperature now in December is 28-33 C°in the day and 22-25 C° in the night, the temperasture can reach to 52 C° in the summer, the environment is dry but recently the we got the rain, I do not know if these mushrooms are seasonal, but I have seen them for the first time. the camel are migrants, but they pass frequently in this place.Following
- Is Loretnz symmetry conserved for all velocity ranges?
I want to know whether Lorentz symmetry is conserved for all the velocity ranges or not?
Is the Lorentz invariance completely related to Lorentz symmetry; i.e. if Lorentz symmetry conserved then Lorentz invariance is also conserved or there are certain conditions where the Lorentz invariance conserved while Lorentz symmetry is not? what are they if there are such conditions.
Symmetry is important for the Lorentz invariance which lead to the laws of physics to be the same for all observeers in the case of Einstein's interpretation to the Lorentz transformation equations depending on the concept of objectivity which adopted by the classical physics. Objectivity means event occurs, then it must occur for all observers. Reinterpretation of the Lorentz transformation according to the Copenhagen school by refusing objectivity will lead to removing the importance symmetry in the Lorentz invariance. And thus that lead also to remove the reciprocity principle which leads to disappearing all the paradoxes in the SRT; the Twin paradox, Ehrenfest paradox, Ladder paradox and Bell's spaceship paradox. Removing objectivity required to multiply the y-axis and z-axis in the Lorentz transformation by the Lorentz factor to interpret the negative result of the Michelson-Morely experiment. In this case the Light speed remains locally constant and equals to the light speed in vacuum. and the Lorentz factor is equivalent to the refractive index in optics, and the Lorentz transformation equations is vacuum energy dependent not on the relative velocity. According to that there is no spacetime continuum, it is only time responsible for measuring a decrease or increase in the speed depending on observation only, but not locally. And this transformation will lead to the wave-particle duality and Heisenberg uncertainty principle and the observed decrease or increase is not only in the light speed but also in the speed of particles of mass and thus interpreting the red-shift of free falling objects in gravity and solving the momentum energy problem in gravity, and that leading to measuring a faster than light without violation the Lorentz transformation Locally. in each quantum state the Lorentz transformation is linear. Furthermore, according to this interpretation I could reconcile and interpret the experimental results of quantum tunneling and entanglement (spooky action), —Casimir effect, Hartman effect. When we generalize we get there is no curved space-time, it is only time responsible for measuring a decrease in the speed of light in gravity and that leads the universe is flat. Reviiew my paper "The Quantization of General Relativity: Photon Mediates Gravitation" http://dx.doi.org/10.14299/ijser.2014.10.002 Also after that review my paper about "The Exact Solution of The Pioneer Anomaly According to The General Theory of Relativity and The Hubble's Law" http://vixra.org/abs/1109.0058Following
- How might forest and farm producers best be represented in the myriad multi-sectoral platforms that decide things on their behalf?
The Forest Farm Facility is strengthening forest farm producer organisations - in part to help them engage in decision-making (see attached report) - but what experience do you have about which platforms it is best to engage and how (Food Security, REDD+, FLEGT, landscapes etc) ?
We have worked in several countries where farmer based on organizations and the NGOs participate in the multisector platform. the challenge is the FBO have several objectives - food security, sustainability, climate smart agriculture, land reforms and so on. So it is important to identify the priorities of the these producer organizations and empower them for the specific purposes they need to participate in the consultations. Such capacity strengthening will in the due course make the FBOs work more towards specific goals and cause and with specific groups they address the issues at the national and local levels. Our recent work in Myanmar indicates that food security networks and Land utilization networks have overlapping members but have distinct role to play in multi-stakeholder platforms.Following
- Are there evidences that all humans descended from a single population of ancestors in Africa?
I read somewhere concerning this hypothesis. Do you know any evidence?
Thank you very much Victor. I already knew this book. It is always refreshing going back to Lefkowitz. Kind regardsFollowing
- Are there any work about the use of statistic survival models (for example, hazard Cox) in health sciences ?
I'm looking for a method to evaluate the vitality of the research group in the field of health sciences (with exception of the estimated mortality). Does anyone know where I can find works that use the statistical method of survival in the natural sciences.Following
- What happens to smallholder farmers who take out microloans from banks then the crop fails?
Was talking to a smallholder farmer in rural Kenya. He took a loan from a local bank to do maize (corn). Unfortunately the crop failed. The Bank is on his neck.
do you think there could be a better way to design these loans to smallholder farmers so that financial tools like loans, meant to empower them do not turn out as torment.
In the context of India - two things happen - one when the crop fails and the loan is form institutional sources, government bails out farmers by scraping the loans. If it is through the local money lender who charges exorbitant rates of interests, farmers loses out part or whole of his land eventually. Farmer suicides are partly a result of such market failures at the grassroots levels where financial markets do not function. well. Strengthening rural financial institutions including provision of insurance options is key for helping the farmers who face frequent crop failures. This attached paper may help.Following
- Why there should be finite number of discontinuities for existence of Fourier Series?
Why there should be finite number of discontinuities for existence of Fourier Series?
For a detailed exsposition of examples of L1 functions with a.e. divergent resp. everywhere divergent Fourier series (two theorems of Kolmogorov), I would recommend the relevant sections of N.K. Bary: A Treatise on Trigonometric Series.Following
- How does color in healthcare environments impact patient experiences?
Colour is believed to be a fundamental element of environmental design, especially in healthcare spaces as it is linked to psychological, physiological, and social reactions of human beings, as well as aesthetic and technical aspects of human-made environments. Choosing a color palette for a specific setting may depend on several factors including geographical location, characteristics of potential users (dominant culture, age, etc.), type of activities that may be performed in this particular environment in specific wards/hospitals in hospitals according to each function (paediatric wards/ cancer hospitals etc) , the nature and character of the light sources, and the size and shape of the space (Ruth et al., 2004).
See a TED Talk about the use of colur in the report of laboratory values for patients by Thomas Goetz, Jan 2011Following
- How can I formulate model on impact of Foreign Aids Reduction?
This question based on developing countries that depend on foreign Aids to support there economic projects.
The answer depends on what are you modeling. Modeling Aid Effectiveness is relatively new field and Foreign Aid can work through various pathways to have an impact on an economy. One of the pathways - depends on for what is spent on - capacity building of the local professionals and institutions. This approach to modeling is carried out in the paper attached. Best wishesFollowing
- What is the cloud point in ternary system containing nonsolvent/solvent/polymer?
what is the cloud point in ternary system containing nonsolvent/solvent/polymer?
Yes, if you're measuring cloud point by starting from high temperature where the ternary blend is determined to be miscible (assuming UCST or "upper critical solution temperature" behavior), and then cooled slowly (or else in small temperature steps isothermally), then your cloud point will trace the binodal or coexistence surface (since it's a ternary diagram) on a Temperature-Composition1-Composition2 plot.
Measurement of the spinodal surface is a lot more challenging, since the spinodal curve comes from a kinetic phenomenon (rate dependence) as opposed to thermodynamic origins (not rate dependent -- ergodic) for the coexistence surface. See for example http://journals.aps.org/pr/abstract/10.1103/PhysRev.185.219Following
- Is Methotrexate contra-indicated in a patient with psoriatic arthritis who has long standing CMV hepatitis?
Is Methotrexate contra-indicated in a patient with psoriatic arthritis who has long standing CMV hepatitis with persistant transaminitis ( ALT & AST 2.5 x ULN) who has a normal liver biopsy?
It seems the hepatotoxicity is direct instead of metabolic, since there's no cyp450 metabolism involved. However I am not 100% sure, I could be wrong. The article could help though.Following
- Do you think obese people tend to have acute pancreatitis without having any etiologic factor fsuch as gallstone, hypertrigliseridemia?
If obesity is an inflammatory condition and can be accepted as a causative condition for acute pancreatitis why all obese people dont have İt?
This review demonstrates that obesity has a clinically relevant impact on the course and outcome of acute pancreatitis.
Premkumar R, Phillips AR, Petrov MS, Windsor JA. The clinical relevance of obesity in acute pancreatitis: Targeted systematic reviews. Pancreatology. 2014 Oct 27. pii: S1424-3903(14)01003-5. doi: 10.1016/j.pan.2014.10.007. [Epub ahead of print].Following
- Does high risk HPV means its seen more frequently in cervical cancers than low risk counterparts?
If so, what is the cut-off level for HPV types to be defined as high risk?Following
- Why do we have to use undifferentiated erythrocytes in micronucleus assay, and why more micronuclei formation indicates more DNA damage ?
plz help T_T
one of the sensitive methods for detecting effects of genotoxicants, is the comet assay.Following
- How can I access comments and critiques to the WEEE directive and its recast (EU)?
I'm particularly interested in the legal debate on this topic, that is, how were the regulations evaluated as presenting feasible strategies, viable procedures and methods for a successful implementation.
Jacobs, Greg: The Implementation of the Regulation of Electrical and Electronic Products (WEEE and RoHS Directives) — An evaluation of the Belgian situation in light of the review of Directive 2002/96/EC and 2002/ 95/EC, European Energy & Environmental Law Review. Aug2008, Vol. 17 Issue 4, p199-212
Watson, Eluned; Crowhurst, Georgina: The Implementation of the WEEE Directive in the UK — A Critical Analysis, European Environmental Law Review. Jun2007, Vol. 16 Issue 6, p163-175
Hristev, Iliyana: RoHS and WEEE -- The New European Directives: Do They Work and Why (Or Why Not)? Current Application and Development in the EU and USA, European Environmental Law Review. Mar2006, Vol. 15 Issue 3, p62-74
Martin, A. D.; Mayers, C. K.; France, C. M.: The EU Restriction of Hazardous Substances Directive: Problems arising from Implementation Differences between Member States and Proposed Solutions, Review of European Community & International Environmental Law. Jul2007, Vol. 16 Issue 2, p217-229Following
- How to define a community garden? Can its characteristics be outlined as a grassroots movement for urban food production regardless its ways of management and participants motivation?
We were dealing with community gardens in two researches, first in Barcelona, Spain and also in Christchurch, New Zealand, within the scope of urban agriculture. You might find some useful information or references in the research reports attached. Good luck with your reviews.
Cheers from Vienna
- Why about 20% of cervical cancer patients are anti-HPV protein negative?
For cervical cancer, it is infected by human papillomavirus that contain two structural proteins and other oncoproteins. But there are about 20% of patients are anti-HPV16 E7 negative. However HPV16 E7 protein is oncoprotein. Why is it? Could anyone give me the answer? Thanks.
HPV may not have a causal relationship with cervical cancer but there is an association exist for sure.Following
- Is there any research on services to agriculture?
I am interested in theoretical frameworks to understand why services to agriculture are increasing and what role services play in improving the competitiveness of small farmers.
I look to different types of services: operational services (machinery,..) and also knowledge-based services (advice, extension...).
We have worked on Extension services and their reforms in several developing countries. A major finding is that knowledge can increase the productivity and hence the competitiveness of smallholder farmers. However, as knowledge intensity increases the extension services need to increase proportionately without which the technologies will not be fully adopted. In fact the adopted technologies will be eventually abandoned. Hope this attached study of System of Rice intensification helps.Following
- What is the biggest scientific coincidence that you know? For me the two more important are:
1. The phase transition liquid-solid for the water is that the solid state is less dense.
2. The dielectric screening in metals is such that the Coulomb interaction among the electrons falls at a distance of the Bohr radius.
The first one has many important applications as the one of allowing the live in rivers during winter or so on. On the other hand, there are also very interesting electric and thermodynamic phase transitions for this material
The second, thanks to have a so local electric interaction it allows to have almost free electrons at quite high electronic density in matter and therefore to apply theories so useful as the bands in solids. Over all in metals
How can a black hole grow? This is an important thing to consider. I think Oppenheimer-Snyder collapse helps answer this question for realistic situations. If you are specifically asking about what happens to the event horizon when a particle falls towards an eternal black hole then I doubt that analytical solutions are possible. However, using basic inferences from the Oppenheimer-Snyder situation we can make an educated guess as to what is likely to happen. General relativity has time-reversal symmetry. This means that event horizons are sensitive not only to the distribution of matter in the past but also in the future (and equally so). This gives them a teleological quality. They can grow in anticipation of the arrival of matter, but not necessarily so that the matter is captured. Rather, I think the the event horizon of an eternal BH would expand just enough to ensure that any additional infalling matter experiences sufficient time dilation to prevent ingestion.
The Schwarzschild metric is of course invalid at the event horizon due to a coordinate singularity and you're right that there is nothing unusual about the curvature there. The event horizon is defined as the surface from within with no events can influence the exterior region. Notice that events in other universes (should any others exist) cannot influence events in this universe either. Do we really need physics to describe other universes?Following
- How can I search a nucleotide database for a given conserved domain?
In a genome database (nucleotide sequence) located in my computer, I would like to identify a given conserved domain, e.g., a given PSSM or a given Pfam.
For this purpose, I looked at PSI-BLAST and DELTA-BLAST, but they are protein-protein search tools, while I need searching a nucleotide database. Similarly, http://pfam.xfam.org/ allows searching protein-protein.
Is there any tool suitable for me to be used locally on my computer?
We also do not have a tradition to use paid software, and as there are good old versions in some places on line, freeware is possible sometimes :) Din't work only for PEAKS, we lost it in Russia, as it is not only impossible for key-treatment but even stubborn to sit in only one computerFollowing
- How can I simulate the majority rule for cooperative sensing of cognitive radio networks in MATLAB?
How can the majority rule be simulated using the AWGN channel and energy detection?
Are you trying to implement a causal or non-causal cognitive behaviors?
Which case do you consider? Interference Avoiding, Controlling, or Mitiagating?Following