Eco-archaeological excavation techniques reveal snapshots of subterranean truffle growth

Despite its status as a highly-prized and coveted fungi in gastronomy, many aspects of the subterranean life cycle of the Burgundy truffle (Tuber aestivum) are still unknown, because in situ observations of the formation and maturation of truffle fruitbodies remain difficult. Here, we adopted a suite of archaeological fine-scale excavating techniques to provide unique spatiotemporal snapshots of Burgundy truffle growth at three sites in southern Germany. We also recorded the relative position, fresh weight, maturity level and genotype composition of all excavated fruitbodies. Varying by a factor of thousand, the fresh weight of 73 truffle ranged from 0.1 to 103.2 g, with individual maturity levels likely representing different life cycle stages from completely unripe to fully ripe and even decaying. While only a slightly positive relationship between fruitbody weight and maturity level was found, our results suggest that genetically distinct specimens can exhibit different life cycle stages at the same period of time and under the same environmental conditions. We therefore argue that truffles are likely able to grow, mature and ripe simultaneously between early summer and late winter of the following year. Our case study should encourage further eco-archaeological truffle excavations under different biogeographic settings and at different seasons of the year to gain deeper insights into the fungi's subterranean ecology. The expected cross-disciplinary findings will help truffle hunters and farmers to improve their harvest practices and management strategies.     

Cavity construction by reintroduced populations of Red‐cockaded Woodpeckers (Dryobates borealis)

Although species reintroduction attempts are now common, monitoring of reintroduction attempts rarely extends beyond initial population establishment. This short timespan likely fails to document long‐term population stability, subtle changes in behavior, and the potentially larger effects that some reintroduced species may have on other species. The Red‐cockaded Woodpecker (RCW; Dryobates borealis) is an important habitat specialist and ecosystem engineer that excavates cavities in living trees. Excavation of natural RCW cavities can take years to complete, but they also persist for many years and are used by many other species. We quantified characteristics of cavity trees excavated by RCWs (n = 44) in two populations that were reintroduced to unoccupied areas more than 10 years earlier. We measured features associated with heartwood rot and used generalized linear mixed effects regression to determine whether these features differed for trees selected for cavity excavation compared with random neighboring trees. We also assessed population trends for cavity‐nesting species that commonly used RCW cavities on one of the sites. Height of first live limb was the only factor distinguishing natural RCW cavity trees from control trees. Four of six cavity‐nesting species monitored increased significantly following RCW establishment. The increases may relate to the many natural and artificial cavities created during the reintroduction effort. Future reintroductions of the RCW should lead to successful natural cavity excavation if sufficiently large trees with smaller live crowns are present. Future efforts may also benefit the broader community of cavity‐nesting birds.     

Testing for Absence of Qualitative Interactions Between Risk Factors and Treatment Effects

The problem of investigating qualitative interactions (QI's) between subsets of patients defined by means of some risk factors, and treatment effects in clinical trials is considered from a viewpoint which leads to interchanging the hypotheses of the testing problem dealed with in the existing literature on QI's. A natural way of approaching this reverse problem is to apply one of the tests available for the original problem of detecting QI's at level 1 — α and to reject the null hypothesis of the new problem if and only if this test accepts. Unfortunately, this would require unbiasedness of the level 1 — α test for existence of QI's to start with, a property which exhibits neither the likelihood ratio procedure derived in the seminal paper of GAIL and SIMON (1985), nor the test based on the extreme order statistics which was introduced by several authors in 1993. Nevertheless we show that there is a valid test for absence of QI's which depends on the extreme values only and coincides with the maximum likelihood ratio procedure for the same problem. Furthermore, the procedure is generalized to the problem of testing for absence of relevant QI's, i.e. of qualitative interactions exceeding some specified tolerance ε > 0.     

Tables for Testing the Equality of Two Proportions when Prior Information on their Common Value May be Available

In testing the equality of two proportions, one may define a rejection point T? such that if the test statistic T (in this paper, the ordinary Pearsonian chi-squared) exceeds T? then the hypothesis may safely be rejected, whatever the common value p of the two proportions may be; and similarly define an acceptance point A? such that if T ≦ T? then one may safely accept. These points may be refined if prior information is available, for example that p must lie in the central interval (c, 1 – c) or one of the extremal intervals (v, w) and (1 – w, 1 – v). Smallsample tables are provided both for the unrestricted case and for situations where one has such prior information.     

Zero crossing rate of electromyograms during occupational work and endurance tests as predictors for work related myalgia in the shoulder/neck region

The relationship between electromyographic signs of fatigue (ESF) during work and occupation-related myalgia in the shoulder/neck region was investigated in a longitudinal study. Forty-three healthy female assembly workers were studied over 2 years. Measurements were performed at the start of the study with follow-up measurements after 1 and 2 years. The ESF were estimated as the zero crossing rate of electromyograms (EMG) detected during short test contractions performed during short breaks in normal work. As a complement, an endurance test using EMG records was performed and analysed with the zero crossing technique. The occurrence of shoulder/neck disorders was assessed by a clinical investigation and a questionnaire. No significant relationship between ESF during work in year 0 and deterioration of the disorder was seen. On the other hand, the absolute zero crossing rate and the time constant of the zero crossing decline from the endurance test showed a significant relationship with deterioration of the disorder. The ESF during work year 2, showed a significant relationship with disorder year 2, while the endurance test parameters year 2 did not. It was concluded that ESF during work was not a predictor of muscle injury, whereas it could be useful as a diagnostic tool.