Biomonitoring studies evaluating air quality via airborne element accumulation patterns in lichens typically control variability by focusing on narrow geographic regions and short time windows. Using samples of the widespread "rock-posy" lichen sampled across the Intermountain Region of the United States, we investigate whether accumulation patterns of generic pollution sources are detectable on broad geographic and temporal scales. We develop a novel Bayesian multivariate receptor modeling (BMRM) approach that sharpens detection and discrimination of candidate pollution sources through (i) regularization of source contributions to each sample and (ii) incorporating estimated lichen secondary chemistry as a factor. Through a simulation study, we demonstrate a distinct advantage in shrinking contributions when they are truly sparse, as would be expected with heterogeneous samples from dispersed collection sites. We contrast analyses employing both standard and sparse BMRMs, and positive matrix factorization (PMF). The sparse model better maintains source identity, as specified though informative prior distributions on elemental profiles. We advocate quantitative profile matching, which reveals that PMF primarily captures variations of the baseline profile for lichen secondary chemistry. Both PMF and BMRM results suggest that the most detectable signatures relate to aeolian dust deposition, while spatial patterns hint at sporadic anthropogenic influence.

Schlüsselwörter: Sommerekzem / Pferdekauf / Empirik / FragebogenEmpiric questionnaire study on purchase behavior of horses suffering from summer eczemaThe occurrence of summer eczema ("sweet itch") after the purchase of a horse often leads to legal proceedings between salesperson, purchaser and the involved veterinarian. In this study details of the purchase behavior of horses suffering from summer eczema and the further development of the disease after the purchase were evaluated by a questionnaire. The primary focus of the study was the clinical status of the skin at the time of purchase and the prepurchase examination. These aspects were analyzed in detail to find out, if dermatological findings were noticed at the time of purchase, which were not diagnosed as summer eczema. Overall, 399 questionnaires were available for statistical analysis. Surprisingly, 41% of horses already presented with symptoms of summer eczema at the time of purchase. 32% presented with pruritus and 30% showed hairless spots in the coat. Horses that presented with numerous hairless spots at the time of purchase, developed summer eczema significantly more severe than horses without or only few hairless spots. Horses suffering from severe pruritus at the time of purchase also developed a significantly more severe course of summer eczema compared to individuals without to moderate pruritus (p < 0.05). In 25% of cases (n=101) a prepurchase examination was performed, but dermatologic findings were only documented in 4% of examination protocols. In 28% of cases the previous owner informed the purchaser about a dermatologic problem. The results of our study show that many horses suffering from summer eczema present with typical symptoms at the time of purchase, but these are not diagnosed as summer eczema or were not assumed to develop into summer eczema later on.Keywords: Summer eczema / sweet itch / pre-purchase examination / questionnaire / empiric Zitation: Gehlen H., Grimm T., Müller-Klein I., Brunner M. (2014) Kaufverhalten bei Pferden mit Sommerekzem -Ergebnisse einer empirischen Fragebogenstudie. Pferdeheilkunde 30,[275][276][277][278][279][280][281][282]