Active learning strategies

Since spring I have been participating in the Saltise S4 activities on the development of Active Learning strategies.

While the majority of the work is focused on Organic Chemistry, I am learning a great deal about active and collaborative learning, while being able to contribute strategies for 2-stage assessments.

I am also hoping to contribute Analytical Chemistry questions to an innovative database of questions for (self) assessment and collaborative learning (MYDALITE), which not only asks for the correct answer, but also requires submission of a rationale and provides (correct and incorrect) rationales to students.

EFSA data — coding for analysis using R

Whenever I have a few hours, I work on the data analysis code for the European Food Safety Authority data on mycotoxins that I have received a few months ago.

plyr and dplyr packages (dplyr is part of tidyverse) have been instrumental to get an overview of the data, answering questions like “How many samples from country X? or How many toxins analysed in sample Y…?” Basic boxplotting of subsets (e.g., from a time range, a specific country or for a specific toxin) provide a crucial overview before conducting a detailed analysis.

The new Environmental Chemistry course

Term has started and so has the Environmental Chemistry course that I have been designing during the last few months. The official name is CHEM 298 — Air, water and soil processes and targeted at students, who have at least completed the first of 3 analytical chemistry courses (who have a good knowledge of aqueous phase equilibria in addition to a solid General Chemistry knowledge).

We do a tour of atmospheric, water and soil chemistry followed by interfacial processes and the analytical tools necessary to monitor concentrations and transfer between environmental compartments.

I have quite a few students, who are really interested in the topic with some engaging discussions, quite early in the course. During a brainstorming exercise students have come up with a range of interesting topics that I will try address during the course.

For the term paper and group presentation (which are part of the assessment together with quizzes and a late midterm exam), I have invited the Science Librarian to give a presentation on search strategies, relevant databases and on how to structure search results. Together with peer review sessions of the paper outline (4 weeks into the term) and a draft (2 weeks before the end of term) it should ease students into term paper writing — for all students taking the course it is the first time that they are writing a term paper!

Food safety data from the European Union

I have successfully requested mycotoxin occurrence data from the European Food Safety Authority (EFSA). It’s been a lengthy, but successful process getting the data (but surprisingly transparent and being kept up to date by the legal department of EFSA), but once all member states had approved the release of their data a CD arrived in the mail a few weeks later with more than 500,000 data sets of regulated mycotoxin concentrations in a variety of raw and processes food matrices.

Together with collaboration partners from Europe, I am now in the process of analysing occurrence data for regulated toxin species. I am setting up a series of analysis scripts in R (using the tidyverse, such as dyplyr and ggplot2) to shed light on the contamination of food products with toxins such as Aflatoxins, Deoxynivalenol and Ochratoxin A.

Summer students hard at work

Over the summer, two summer students have been hard at work designing and building an air sampler for volatile organic compounds. The sampler is SPME-based and analysis is performed using GC-MS. Initial testing showed promising results for ambient outdoor air.

An advanced undergraduate students will be testing and characterising the sampler as part of his final year research project!

News on 2-stage assessments

I have now implemented 2-stage exams for all my courses (currently Analytical Chemistry 1 and 2, and Thermodynamics.

It’s been smooth sailing and the feedback from students has been very positive. They like that they know immediately, how they did on the individual exam and the fact that they can review the concepts with other students during the group stage.

There were a few issues to address during the implementation and apart from scheduling and training TAs, accommodating students writing with the Access Office for Students with Disabilities (ACSD) at Concordia has been the most important one. My priority is to have students writing the individual exam with ACSD write the group exam with the rest of the students together so that they can join the group they have been working with during the term. And support from ACSD has been great regarding scheduling individual start times so that all students are on time for the group stage at the common exam room. This has, so far, worked for midterms and finals!

Mycotoxin analysis with laser spectroscopy and machine learning

I have co-authored a paper on portable infrared laser spectroscopy for on-site mycotoxin analysis, which nicely demonstrates future applications of spectroscopy — a combination of new powerful laser light sources (quantum cascade lasers) paired with machine learning allows for extraction of information from spectra of complex samples such as food and environmental matrices.

In this case toxin concentrations of a potent natural carcinogen (Aflatoxin B1) were used to discriminate samples at (the very low, 8 ppb) established legal limits.

Portable sensors are most useful for preliminary large scale screening on site.

http://dx.doi.org/10.1038/srep44028

The full text of the Canadian mercury science assessment…

… is now available online! Check out this link to the catalogue entry or access the full text as PDF directly in English and French.

My contribution on Canadian and Global emissions is part of this report: G. Kos, Y.-F. Li, D. Niemi, M. King, S.A. Smyth, C. Zdanowicz, J. Zheng, Releases of Mercury into Air and Water from Anthropogenic Activities in North America.

New research is out

New research that I was involved in has been published recently — here are the articles that are now available

Y. Nazarenko, R.B. Rangel-Alvarado, G. Kos, U. Kurien, P.A. Ariya, Novel Aerosol Analysis Approach for Characterization of Nanoparticulate Matter in Snow, Environmental Science and Pollution Research (2016), doi: 10.1007/s11356-016-8199-3

This work is a reanalysis of snow samples that I have collected during my Arctic field trips with a focus on nanoparticles.

P. Kovalsky, G. Kos, K. Nährer, C. Schwab, T. Jenkins, G. Schatzmayr, M. Sulyok, R. Krska, Co-occurrence of Regulated, Masked and Emerging Mycotoxins and Secondary Metabolites in Finished Feed and Maize – an Extensive Survey, Toxins 8 (2016), 363, doi: 10.3390/toxins8120363

The manuscript provides an extensive and detailed statistical analysis of 1900+ finished feed, maize and maize silage samples from 40+ countries. 50+ fungal toxins and secondary metabolites were determined and evaluated with a focus on co-occurrence and correlation of concentrations. The analysis was performed using Matlab and R.

G. Kos, M. Sieger, D. McMullin, C. Zahradnik, T. Öner, B. Mizaikoff, R. Krska, A Novel Chemometric Classification for FTIR Spectra of Mycotoxin-contaminated Maize and Peanuts at Regulatory Limits, Food Additives and Contaminants, Part A 33 (2016), 1596-1607, doi: 10.1080/19440049.2016.1217567

As a collaborator on the EU funded Mycospec project, I have modelled mycotoxin contamination levels from mid-infrared data. Focus was the implementation of non-parametric machine learning algorithms such as bagged decision trees and a comparison with standard (and generally accepted) principal component analysis results. The analysis was performed using Matlab.

Two-stage Exams

I have recently successfully tested two-stage exam s as part of the Analytical Chemistry course that I teach at Concordia. I chose the long 2 1/2 hour evening section to have enough time for teach step:

  1. Individual exam (1hr 15 min)
  2. Group exam (30 min)
  3. Discussion of solutions (15 min)

Feedback was overwhelmingly positive and I now work on expanding this assessment to all of the courses I teach, including the 1hr 15 min day sections, where I will most probably opt for a 40 min individual exam, followed by a 25 min group exam.