Pyrogenic carbon soluble fraction is larger and more aromatic in aged charcoal than in fresh charcoal

Recent studies show that pyrogenic matter is one of the most stable compounds in the soil but less inert than previously expected. One potential pathway yielding losses from soil is solubilisation of pyrogenic compounds. In batch experiments, we estimated the proportion and molecular composition of soluble (<0.45 μm) and colloidal fractions (0.45-5 μm) extractable from a freshly pyrolysed charcoal and a 10 year old wildfire charcoal. These fractions represented a very small fraction (<2.7 g kg⁻¹) of chars. The benzene polycarboxylic acids (BPCA) pattern indicated that 40-55 times more condensed structures were released from the aged char than from the fresh char. This study shows that the soluble fraction of the char is small, and tends to increase with the residence time in the soil.     

Nordic dairy farmers’ threshold for contacting a veterinarian and consequences for disease recording: Mild clinical mastitis as an example

Previous studies have addressed the differences in registered disease incidence between the Nordic dairy disease recording systems. The main objective of this study was to investigate whether Nordic dairy farmers have varying intention to contact a veterinarian the same day as detecting signs of mild clinical mastitis (MCM) in a lactating dairy cow. This is the first, and necessary, step in the process leading to a disease event being recorded. The second objective was to study underlying behavioural components influencing this threshold for action.A questionnaire-based survey was carried out in Denmark, Finland, Norway and Sweden. The questionnaire was based on the Theory of Planned Behaviour from the field of social psychology. After performing qualitative face-to-face elicitation interviews a set of statements about treatment of MCM was identified. These were grouped into behavioural, normative and control beliefs. The most frequently mentioned beliefs were rephrased as questions. Behavioural intention, a proxy for the behaviour of interest, was assessed using case scenarios. The target and eligible herds were in milk recording and had an average herd size of at least 15 cows. The questionnaire was distributed to 400 randomly sampled dairy producers per included country. The response rate was around 50% in all four countries.The hypothesis of differences in behavioural intention between the countries was tested using Wilcoxon's rank-sum tests. Multivariable linear regression was used to estimate the country-specific variability in behavioural intention as explained by attitude, subjective norm or perceived behavioural control alone, or in combination. The Spearman rank correlations between behavioural intention and each belief, weighted by its outcome evaluation or the motivation to comply, were estimated to find the most important drivers, constraints and social referents for the behaviour of interest.There were significant (p < 0.01) differences in behavioural intention between all countries except Denmark and Norway. Swedish farmers had the weakest behavioural intention and Finnish farmers the strongest. Attitude explained most of the variability in behavioural intention in all four countries. The most important driver in all countries was to achieve a quick recovery for the cow.The varying behavioural intention partly explain the differences in completeness of disease data in the Nordic countries: if farmers have different thresholds for contacting a veterinarian the registered incidence of clinical mastitis will be affected. Knowledge about the importance of attitudes and specific drivers may be useful in any communication about mastitis management in the Nordic countries.     

Effect of bacitracin on tetracycline resistance in Escherichia coli and Salmonella

Tetracyclines and bacitracin are used extensively as a growth promotant and a therapeutic, respectively in livestock. In this study, we test whether there is an interaction between bacitracin and tetracycline that can select for an increase in microbial tetracycline sensitivity, using Escherichia coli and Salmonella as a model. We found via in vitro studies that bacitracin at sublethal concentrations preferentially selects for outgrowth of tetracycline-sensitive bacteria from among a population of tetracycline-resistant and tetracycline-sensitive E. coli and Salmonella strains. Most of the bacterial strains employed in our study were shown by PCR to possess the tetracycline resistance gene tet(A) or tet(C), either of whose activity is associated with tetracycline efflux. Bacitracin could be substituted for the lipophylic chelator, fusaric acid, used as a positive selective agent for tetracycline sensitivity. Together, these observations suggest that bacitracin-mediated selection for tetracycline sensitivity alters the function of tetracycline efflux proteins. Using bacitracin and tetracycline simultaneously may improve the effectiveness of the antibiotics, while decreasing the risk of selecting for a population of tetracycline-resistant microorganisms.     

Melanin pigmentation: an in vivo model for studies of melanosome kinetics within keratinocytes

The phagocytosis of latex beads by epidermal cells is proposed as a model for stludies on melanosome kinetics within the epidermis. Large latex beads (0.8 micrometer) are ingested singly, whereas, small beads (0.1 micrometer) are taken up in groups, results showing that the uptake mechanism depends on the size of thze indlividual particles. This size-dependency may explain the different distribution patterns of melanosomes and thus the differences of skin color in the Caucasoid and Negroid races.     

Increases in the completeness of disease records in dairy databases following changes in the criteria determining whether a record counts as correct

Background

The four Nordic countries: Denmark (DK), Finland (FIN), Norway (NO) and Sweden (SE), all have national databases in which mainly records of treated animals are maintained. Recently, the completeness of locomotor disorder records in these databases has been evaluated using farmers’ recordings as a reference level. The objective of the present study was to see how previous estimates of completeness figures are affected by the criteria determining whether a recording in the database is to be judged correct. These demands included date of diagnosis and disease classification. In contrast with the previous study, a period of time between the date of disease recording in the database and by the farmer was allowed. Further, the calculations were brought to bear on individual locomotor diagnoses instead of a common locomotor disease complex code.

Methods

Randomly selected dairy herds (≥ 15 cows) were invited to participate. During two 2-month periods in 2008 the farmers recorded the diseases they observed on the farm and their recordings constituted a farmer database (FD). These recordings were compared to disease recordings in the National Databases (ND). Earlier calculations of completeness for locomotor complex cases assuming an exact match on date were compared with ±7 day and ±30 day discrepancies calculated in this study.

Results

The farmers in DK, FIN, NO and SE recorded 426, 147, 97 and 193 locomotor disorders, respectively. When a window of ±7 days was allowed there was a relative increase in completeness figures lying in the range of 24–100%. Further increases were minor, or non-existent, when the window was expanded to ±30 days. The same trend was seen for individual diagnoses.

Conclusion

In all four of the Nordic countries a common pattern can be observed: a further increase in completeness occurs when individual locomotor diagnoses recorded by the farmer are permitted to match any locomotor diagnosis recorded in the ND. Completeness increased when both time span and different diagnoses within the locomotor complex were allowed.     

Completeness of metabolic disease recordings in Nordic national databases for dairy cows

The four Nordic countries Denmark (DK), Finland (FI), Norway (NO) and Sweden (SE) all have national databases where diagnostic events in dairy cows are recorded. Comparing and looking at differences in disease occurrence between countries may give information on factors that influence disease occurrence, optimal diseases control and treatment strategies. For such comparisons to be valid, the data in these databases should be standardised and of good quality. The objective of the study presented here was to assess the quality of metabolic disease recordings, primarily milk fever and ketosis, in four Nordic national databases. Completeness of recording figures of database registrations at two different levels was chosen as a measure of data quality. Firstly, completeness of recording of all disease events on a farm regardless of veterinary involvement, called 'Farmer observed completeness', was determined. Secondly, completeness of recording of veterinary treated disease events only, called 'Veterinary treated completeness', was determined. To collect data for calculating these completeness levels a simple random sample of herds was obtained in each country. Farmers who were willing to participate, recorded for 4 months in 2008, on a purpose made registration form, any observed illness in cows, regardless of veterinary involvement. The number of participating herds was 105, 167, 179 and 129 in DK, FI, NO and SE respectively. In total these herds registered 247, 248, 177 and 218 metabolic events for analysis in DK, FI, NO and SE, respectively. Data from national databases were subsequently extracted, and the two sources of data were matched to find the proportion, or completeness, of diagnostic events registered by farmers that also existed in national databases. Matching was done using a common diagnostic code system and allowed for a discrepancy of 7 days for registered date of the event. For milk fever, the Farmer observed completeness was 77%, 67%, 79% and 79%, and for Veterinary treated completeness 88%, 71%, 80% and 82%, in DK, FI, NO and SE, respectively. For ketosis, the Farmer observed completeness was 77%, 55%, 70% and 46%, and for Veterinary treated completeness 84%, 75%, 79% and 56%, in DK, FI, NO and SE, respectively. The differences observed in some of these completeness figures indicate that metabolic disease frequency measures when calculated from these four national databases do not accurately reflect the true difference in metabolic disease occurrence in dairy cows between countries. Further standardisation of disease registrations is necessary for valid between-country assessments.     

Influence of the lethal yellow (Ay) gene on estrous synchrony in mice

Introduction of an adult male induces partially synchronous estrus in female laboratory mice that have been caged in groups. In the inbred YS/ChWf strain, this effect was observed only when the male was nonyellow (aa), while males heterozygous for the lethal yellow allele (A(y)a) failed to induce synchrony.