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Abstract Background We expect a difference in drug cost between private drug plans and the Public Drug Plan (PDP) because the dispensing fee is fixed and regulated by the PDP for publicly insured patients, whereas it is determined freely by the pharmacy owner for privately insured patients. This study compared the drug cost of Quebec residents covered by private drug plans with those covered by PDP. Methods We used a sample of prescriptions filled between 1 January 2015 and 23 May 2019 selected from reMed, a database of Quebecers’ drug claims. We created strata of prescriptions filled by privately insured patients and matched them with strata of prescriptions filled by publicly insured patients based on the Drug Identification Number, quantity dispensed, number of days of supply, pharmacy identifier, and a date corresponding to the publication of List of Medications of Régie de l’Assurance Maladie du Québec. The differences in drug cost between private plans and the PDP were analyzed with linear regression models using prescription strata as the unit of analysis. Results Based on 38 896 prescription strata, we observed that privately insured patients payed $9·35 (95% confidence interval [CI]: 5·58; 13·01) more on average per drug prescription than publicly insured patients, representing a difference of 17·6%. Conclusions This study showed that, on average, drug cost is substantially higher for privately insured Quebecers. Knowing that adherence to treatment is affected by drug cost, these results will help public health authorities to make informed decisions about drug policies.

Agricultural practices determine the level of soil organic C by influencing the amount of residue returned to, and retained by, soil. We conducted field experiments on four soils in Ontario and Quebec to test the hypothesis that short-term changes in soil organic C and the proportion of corn (Zea mays L.)-residue C retained in soils are affected by soil texture, fertility, and tillage management. We measured the amount of stover to estimate C input into the soils, and total soil C and 13C natural abundance to determine the soil C derived from corn residues. Only the sandy clay loam exhibited changes in total soil C, related to levels of fertilizer N and quantity of residues returned to the soil. The proportion of soil C derived from corn residues varied from 4 to 19%, depending on the time under continuous corn. Our data indicate a rapid increase in the proportion of corn-derived C in the early stage of cropping to corn, but a markedly reduced rate of increase beyond 12 yr. Measured [[Delta].sup.13]C of archived samples of two soils with different clay contents (71 and 28% clay) but similar residue inputs (11 Mg stover [ha.sup.-1] [yr.sup.-1]) indicated that the rate of increase in the proportion of corn-derived C was higher in the soil with higher clay content (2.4 vs. 1.9% [yr.sup.-1]). The results of this study are consistent with the hypothesis that the quantity of crop residue inputs and soil texture greatly influence the retention and turnover of crop residue C.

To uncover possible chemical differences between stockpiled and composted dairy manures, water extracts of these manures were analyzed by 13C nuclear magnetic resonance (NMR) and by pyrolysis-field ionization mass spectrometry (Py-FIMS). Judging from the 13C NMR, which took into consideration all of the organic C present, aliphatic and aromatic C in the composted and stockpiled manure extracts were similar but the composted manure extract appeared to be richer in protein C, phenolic C, and carboxylic C and poorer in carbohydrate C than the stockpiled manure extract. Major components of the extract of the stockpiled manure extract determined by Py-FIMS, which measured only volatile organics, were N compounds > phenols + monolignins > carbohydrates > alkylaromatics > peptides = lipids > lignin dimers > sterols > fatty acids > suberins. On the other hand, the quantitative order of organic components of the composted manure extract was phenols + monolignins > N compounds > carbohydrates > peptides > alkylaromatics > lipids > fatty acids > sterols = lignin dimers > suberins. The relatively low total ion intensity of the water extract of the composted manure and its greater aromaticity suggested that composting increased polymerization and cross-linking and so led to the formation of larger molecules. Water-soluble organic C (DOC) extracted from the manures was used to study adsorption isotherms on soils varying in clay content from 3 to 54%. The adsorption of the DOC by the soils increased as the clay and organic matter contents and the surface areas of the soils increased. Increased adsorption of the DOC extracted from the composted manure appeared to be due to increased molecular weights of the major DOC components.

Pyrolysis-field ionization mass spectrometry (Py-FIMS) helps estimate the carbon content and total amount of starting minerals in fulvic acid (FA) and five other FA-mineral mixtures. Py-FIMS identifies six groups of FA components and examines the influence of minerals on the thermal evolution of these compounds during pyrolysis. The relation between FA-mineral mixture and thermal evolution and the retention of FA-component in different FA-complexes are discussed.

The application of pyrolysis-field ionization mass spectrometry to whole soils, humic acid, fulvic acid and humins extracted from these soils is discussed. Soil samples were pyrolyzed under vacuum directly in the ion source of the mass spectrometer. Field ionization mass spectrometry identified volatile components. Results indicate that whole soils are most suitable for the analysis of organic matter in soils.

Possible interactions between the organic and inorganic components in particle-size isolates were investigated. No conclusive interrelationships between organic and inorganic soil components was found. The composition of the inorganic soil components appeared to influence the type of organic matter which accumulated in the various soils used. Preferential deposition of the various carbon and nitrogen compounds was also observed.