What is the best method for alkaloid extraction?

A student of mine is doing her thesis and needs to perform alkaloid extraction from a set of officinal drugs and has asked me for the best way to perform it. Now, the two main methods I can think...

06 November 2020 3,086 5 View

Motivations for Play in Online Item Inventory of Yee (2006) - Spanish Version?

Hello! Is someone aware of if exist a Spanish version of the Motivations for Play in Online item inventory created by Yee (2006)? I found a French version, but not a Spanish one. Yee, N. (2006)....

26 March 2020 2,027 3 View

Why does my PCR not show whether my mice are homozygous or heterozygous for a floxed gene?

So, I am trying to determine whether my mice are homozygous or heterozygous for a floxed gene. I ordered the primers specified by the company which developed the mice and they amplify a 301 bp...

10 March 2020 9,740 4 View

Can anyone identify this microorganism?

My vesicle samples get constantly contaminated by these strange microorganisms, that unfortunately I'm not able to identify. Does anyone know which species is it and how to avoid them? Our samples...

10 November 2018 2,327 6 View

Time trend analysis and sample size?

I am trying to determine if certain contaminants are decreasing in birds over time (1960-Present). Data was pulled from the literature and I've grouped birds based on their dietary habits. When I...

22 June 2018 5,315 3 View

In the Raman spectra, why in some cases band D moves to the left and in other cases moves to the right?

I am analyzing carbon nanotubes by nanocasting (MNC), using SBA15 as a hard template. Composite C-SBA15 is the intermediate material with the carbon precursor within the SBA15 channels. In the...

14 May 2018 5,813 4 View

What are possible substitutes for P2O5 as a desiccant?

I've been using phosphorus pentoxide as the desiccant while drying my enzymes; however, our stockroom has now run out of the chemical. What are other chemicals that can be used as desiccants that...

12 January 2018 8,072 4 View

It is possible to make turmeric/derivates soluble in water? How?

Curcumins, curcuminoids water soluble... it is possible???

20 March 2017 3,468 9 View

How to deal with the ndvi range variation from landsat 7 and landsat 8?

I try to study the vegetation change using NDVI from landsat 7 and landsat 8 wherein the maximum NDVI value for NDVI from landsat 7 is 0.8 whereas for the NDVI from Landsat 8 is only 0.6 but...

21 October 2016 1,158 9 View

Why MLP is not converging?

05 October 2016 3,817 8 View

Am i able to conduct a factor analysis on each of my subscales, as opposed to the whole scale?

My psychometric scale contains 38 items in total, with 4 subscales (20, 6, 6 & 6 items respectively? Can i run a factor analysis for each subscale rather than the scale as a whole for the...

24 February 2021 8,856 8 View

What are alternatives to factor analysis for a small sample?

My sample size is too small to conduct a factor analysis. I created my own psychometric scale for measuring Effectiveness of Support, which contains 38 items (4 sub-scales) Im really struggling...

23 February 2021 9,287 12 View

How do I collect online measures in a same-different task?

The same-different task requires to subjects to indicate whether a pair of stimuli seen or heard are the same (say AA or BB) or different (say AB or BA). Researchers often collect offline measures...

20 February 2021 9,226 2 View

How many indicators do I need to represent a latent construct?

Hi folks! We did a large survey and planned to use 3 indicators to represent a latent construct (Sense of Place/SoP) in a latent regression model (structural equation modeling). However, one of...

15 February 2021 7,705 3 View

How to use PVQ Psychometric Tool?

Hello, I'm doing a research about if psychometric tools can be translated into video games. My main major is video games. So I'm an absolute newbie with psychometric tools. I have chosen PVQ tool...

22 January 2021 5,992 2 View

Cronbach's alpha or McDonald's omega? Which would be more correct and in what cases?

Cronbach's alpha or McDonald's omega? When it comes to reliability, we find different methods for its estimation. Immediately, the name of Cronbach's Alpha coefficient arises, as it is the most...

21 January 2021 330 4 View

How did the tests or exams get to Latin America, specifically the written tests?

I am looking for some bibliographic references that explain how tests or exams (measurement and assessment in education) came to Latin America, specifically written tests. I would like to know if...

13 January 2021 8,607 0 View

In psychometrics, what are some quant. methods to examine several competing operationalizations of the same construct to see which is most 'valid'?

13 January 2021 2,740 3 View

Any free + psychometrically robust I. Q. Test measuring Verbal, Numerical & Logical Reasoning?

Looking for a free + psychometrically robust Intelligence Test that measures the "g" factor + verbal, numerical & logical reasoning abilities to run a Concurrent Validity Study.

20 December 2020 4,301 3 View

Measurement invariance of a bifactor model with categorical indicators. What is the recommended approach?

I have a bifactor model with categorical indicators: 4-option Likert-type items. One of my research objectives involves testing measurement invariance between two groups. I have been doing it as...

16 December 2020 4,601 2 View