Evaluation of the level of difficulty of patient cases for veterinary problem-solving examination: a preliminary comparison of three taxonomies of learning

An important issue that has received insufficient attention in the use of problem-based learning in the medical curriculum is the mode of assessing the level of difficulty of patient cases. In the present study, the level of difficulty of case-based questions in a veterinary degree final examination in reproduction was evaluated. First, cognitive taxonomies were evaluated to clarify whether qualitative methods such as Bloom's taxonomy, the Structure of the Observed Learning Outcome (SOLO) taxonomy, and the Amsterdam Clinical Challenge Scale (ACCS) differed from each other as evaluation tools for problem-based cases. Using these taxonomies, 30 case-based questions from the final examination in reproduction in the Helsinki veterinary program were initially evaluated to determine which one was best suited to the evaluation of the difficulty of cases. In follow-up, the same cases were also evaluated by an experienced veterinary instructor in reproduction, with the aim of gaining insight into using these approaches to evaluating difficulty. It would appear, from this preliminary assessment, that the SOLO taxonomy may be the most suitable for evaluating the difficulty of patient cases, since the instructor's quality rating resembled more closely the SOLO than the Bloom taxonomy or the ACCS. It is to be emphasized that the purpose of this study was to provide a preliminary evaluation of possible approaches that might be used to assess patient-case difficulty. Resolving all issues will require a greater number of evaluations of all components.     

Fate of phosphorus in soil during a long‐term fertilization experiment in Finland

Accumulation and depletion of soil phosphorus (P) was studied in a long‐term (37 y) field experiment in Southern Finland. The loam soil had a high pH (7.5–7.7) due to an earlier liming. Spring barley, spring wheat, oat, and ryegrass, grown in rotation, were annually fertilized with 0, 32, or 67 kg P ha^?1 y^?1 (P₀, P₁, and P₂K) and sufficient N. The average dry matter grain yield 2,600 kg ha^?1 of the P₀ plots increased by about 500 kg ha^?1 at P₁ treatment and another 600 kg ha^?1 by P₂K. Soil samples were collected in 1978 (beginning), 1995, 2005, and 2015. According to the Chang and Jackson sequential extraction, the P₂K and P₁ treatments increased the inorganic soil P by 732 and 32 kg P ha ^?1 in 37 years, respectively, while the P₀ plots were depleted by –459 kg P ha ^?1. The P₂K treatment increased all four P fractions, extracted with NH₄Cl (easily soluble), NH₄F (Al‐P), NaOH (Fe‐P), and H₂SO₄ (Ca‐P). Continuous depletion (P₀) decreased the NH₄Cl‐P and NH₄F‐P pools, NaOH‐P and H₂SO₄‐P pools remaining stable. None of the P pools changed significantly at P₁. The remarkable gap between the measured change and the balance for the P₂K and P₁ treatments cannot be explained solely by lateral soil movement, meaning that a significant proportion of the applied P was lost either in surface runoff or transported below the investigated depth of 40 cm. Despite large P applications, the degree of P saturation reached only 20% in the P₂K topsoil, assuming a 50% reactivity of Fe and Al oxides. As derived from sorption isotherms, a high EPC₀ (i.e., equilibrium P concentration at zero net P sorption or desorption) of 1.30 mg L^?1 had been built up in the P₂K treatment, while in the P₁ treatment EPC₀ (0.33 mg L^?1) had remained unchanged and P depletion (P₀) had caused a decrease to 0.12 mg L^?1. These results demonstrate that P sorption and desorption properties respond strongly to both P fertilization and null fertilization treatments and that in a long‐term field experiment only a low proportion of the residual fertilizer P can be recovered from soil.     

Atmospheric Mercury Fluxes in a Southern Boreal Forest and Wetland

Total gaseous mercury (TGM) fluxes from the forest floor and a boreal wetland were measured by a flux chamber technique coupled with an automatic mercury vapour analyser. The fluxes were measured at three sampling sites in southern Finland, 61°14′ N, 25°04′ E in summer 2007, with additionally in situ TGM concentrations in the air at one of the sites and mercury bulk deposition at another. Most of the flux data were collected during the daytime. At one of the sites, diurnal flux behaviour was studied, and a clear cycle with an afternoon maximum and a night minimum was observed. The highest emissions (up to 3.5 ng m⁻² h⁻¹) were observed at the forest floor site having a moss and grass cover. At the wetland and litter-rich forest floor sites, the emissions were below 1 ng m⁻² h⁻¹ and sometimes negative (down to −1.0 ng m⁻² h⁻¹), indicating mercury uptake. The measured average fluxes in August were 0.9 ± 1.1 and 0.2 ± 0.3 ng m⁻² h⁻¹ for the forest floor sites and wetland sites, respectively. The flux data were compared with the mercury bulk deposition, which proved to be of the same magnitude, but opposite in sign. At the mossy forest floor site, the extrapolated TGM emissions were 130% of the Hg deposition in August 2007. Comparison with other studies showed that the fluxes in background areas are relatively uniform, regardless of measurement site location and method used. Airborne TGM remained at the background level during the study, with an average value of 1.3 ± 0.2 ng m⁻³; it frequently showed a diurnal cycle pattern.     

Absorption of flavonols derived from sea buckthorn (Hippophaë rhamnoides L.) and their effect on emerging risk factors for cardiovascular disease in humans

Sea buckthorn (Hippopha? rhamnoides L.) is a rich source of flavonols, especially isorhamnetin. Most prospective cohort studies have indicated some degree of inverse association between flavonoid intake and coronary heart disease. Animal and human studies suggest that sea buckthorn flavonoids may scavenge free radicals, lower blood viscosity, and enhance cardiac function. The effects of flavonol aglycones derived from sea buckthorn on the risk factors of cardiovascular disease as well as their absorption were studied in humans. The flavonols, ingested with oatmeal porridge, did not have a significant effect on the levels of oxidized low-density lipoprotein, C-reactive protein, and homocysteine, on the plasma antioxidant potential, or on the paraoxonase activity. Flavonols at two dosages in oatmeal porridge were rapidly absorbed, and a relatively small amount of sea buckthorn oil added to the porridge seemed to have increased the bioavailability of sea buckthorn flavonols consumed at the higher dose.     

Fate of diuron and terbuthylazine in soils amended with two-phase olive oil mill waste

The addition of organic amendments to soil increases soil organic matter content and stimulates soil microbial activity. Thus, processes affecting herbicide fate in the soil should be affected. The objective of this work was to investigate the effect of olive oil production industry organic waste (alperujo) on soil sorption-desorption, degradation, and leaching of diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] and terbuthylazine [N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine], two herbicides widely used in olive crops. The soils used in this study were a sandy soil and a silty clay soil from two different olive groves. The sandy soil was amended in the laboratory with fresh (uncomposted) alperujo at the rate of 10% w/w, and the silty clay soil was amended in the field with fresh alperujo at the rate of 256 kg per tree during 4 years and in the laboratory with fresh or composted alperujo. Sorption of both herbicides increased in laboratory-amended soils as compared to unamended or field-amended soils, and this process was less reversible in laboratory-amended soils, except for diuron in amended sandy soil. Addition of alperujo to soils increased half-lives of the herbicides in most of the soils. Diuron and terbuthylazine leached through unamended sandy soil, but no herbicide was detected in laboratory-amended soil. Diuron did not leach through amended or unamended silty clay soil, whereas small amounts of terbuthylazine were detected in leachates from unamended soil. Despite their higher sorption capacity, greater amounts of terbuthylazine were found in the leachates from amended silty clay soils. The amounts of dissolved organic matter from alperujo and the degree of humification can affect sorption, degradation, and leaching of these two classes of herbicides in soils. It appears that adding alperujo to soil would not have adverse impacts on the behavior of herbicides in olive production.     

Influence of soil pH-sorption interactions on imazethapyr carry-over

Soil pH affects imazethapyr sorption-desorption, which in turn can affect persistence and bioavailability. Long-term imazethapyr carry-over has been observed in soil that is below pH 6.5, resulting in significant sugarbeet damage. Imazethapyr concentration decreased rapidly in field soil, regardless of pH. Despite similar amounts of imazethapyr remaining in aged soils at different pH levels, there were differences in bioavailability, which can be explained by sorption-desorption. At low pH more imazethapyr was sorbed than at high pH, but it readily desorbed. At high pH less imazethapyr was sorbed initially, but it did not readily desorb. Thus, after 3 months, the remaining imazethapyr in low-pH soil was desorbable and bioavailable, resulting in injury to canola and sugarbeet. Liming aged, low-pH soil released bound imazethapyr residues, which would then be degraded and result in less carry-over.     

Metsulfuron methyl sorption-desorption in field-moist soils

Pesticide sorption coefficients (K(d)) are generally obtained using batch slurry methods. As a consequence, the results may not adequately reflect sorption processes in field-moist or unsaturated soil. The objective of this study was to determine sorption of metsulfuron methyl, a weak acid, in field-moist soils. Experiments were performed using low density (i.e., 0.3 g mL(-)(1)) supercritical fluid carbon dioxide (SF-CO(2)) to convert anionic metsulfuron methyl to the molecular species and remove it from the soil water phase only, thus allowing calculation of sorption coefficients (K(d)) at low water contents. K(d) values for sorption of the metsulfuron methyl molecular species on sandy loam, silt loam, and clay loam soil at 11% water content were 120, 180, and 320 mL g(-)(1), respectively. Using neutral species K(d) values, the pK(a) of metsulfuron methyl, and the pH of the soil, we could successfully predict the K(d) values obtained using the batch slurry technique, which typically has a predominance of anionic species in solution during the sorption characterization. This application of supercritical fluid extraction to determine sorption coefficients, combined with sulfonylureas' pK(a) values and the soil pH, will provide an easy method to predict sorption in soil at different pH levels.     

Freezing of stallion semen with addition of glycine betaine

The effect of addition of glycine betaine to a lactose-EDTA freezing medium on the post-thaw motility of stallion semen was determined. The first three semen-rich fractions of nine stallions were collected with an open-end Krakow artificial vagina on consecutive weekdays. Semen was frozen using the Hannover method with freezing media containing glycine betaine in various concentrations from 0 to 5%. After thawing, sperm motility was analysed both by a light microscope and by a Hamilton-Thorn Motility Analyser. Total and progressive post-thaw motilities of semen containing 0.25-3% glycine betaine did not differ significantly from the total and progressive post-thaw motilities of semen frozen without glycine betaine. The total and progressive post-thaw motilities of semen containing 4 or 5% glycine betaine were significantly lower (P < 0.001) than those of semen without glycine betaine. In conclusion, glycine betaine did not show any beneficial effect on the post-thaw motility of stallion semen when semen was frozen using the Hannover method.     

Knotwood and bark extracts: strong antioxidants from waste materials

The antioxidant properties of hydrophilic extracts of knotwood of several industrially important tree species were evaluated by lipid-peroxidation inhibition and peroxyl-trapping capacity tests. The results were compared with the antioxidant properties of hydrophilic extracts of bark, and pure lignans and flavonoids isolated from knotwood extracts. The knot extracts from several tree species were stronger antioxidants than the bark extracts, which can, however, also be classified as strong antioxidants. In addition, the antioxidant properties of most of the knotwood extracts are stronger than the pure compounds. It is concluded that knotwood is a rich source of natural antioxidants.     

Biodiversity policies in commercial boreal forests: Optimal design of subsidy and tax combinations

This paper examines the first-best instruments for biodiversity maintenance in commercial boreal forests when landowners behave either in Faustmannian or Hartmanian way. Using an extended Hartman model, we show that biodiversity conservation requires both prolonged rotation age and leaving retention trees. While the former promotes some old growth species, the latter create new structural elements of decaying and dead wood, which can sustain a variety of saprolyxic species. A fully synchronized combination of retention tree subsidy and tax instrument is needed both to lengthen the privately optimal rotation period and to provide an incentive to leave retention trees. Using Finnish data we illustrate empirically the sizes of instruments. When combined with a harvest tax, the retention tree subsidy is 1000 and 750 € in the Faustmann and in the Hartman model, respectively. When used with a timber subsidy or a site value tax, the retention tree subsidy is 1700 €/ha in both models. The harvest tax rate varies over the range 40–65% in the Faustmann model and 20–40% in the Hartman model, while timber subsidy is between 0.5–1.0% and site value tax is about 1.75%.