Scaling relations between trabecular bone volume fraction and microstructure at different skeletal sites

In this study, we investigated the scaling relations between trabecular bone volume fraction (BV/TV) and parameters of the trabecular microstructure at different skeletal sites. Cylindrical bone samples with a diameter of 8mm were harvested from different skeletal sites of 154 human donors in vitro: 87 from the distal radius, 59/69 from the thoracic/lumbar spine, 51 from the femoral neck, and 83 from the greater trochanter. μCT images were obtained with an isotropic spatial resolution of 26μm. BV/TV and trabecular microstructure parameters (TbN, TbTh, TbSp, scaling indices (< > and σ of α and αz), and Minkowski Functionals (Surface, Curvature, Euler)) were computed for each sample. The regression coefficient β was determined for each skeletal site as the slope of a linear fit in the double-logarithmic representations of the correlations of BV/TV versus the respective microstructure parameter. Statistically significant correlation coefficients ranging from r=0.36 to r=0.97 were observed for BV/TV versus microstructure parameters, except for Curvature and Euler. The regression coefficients β were 0.19 to 0.23 (TbN), 0.21 to 0.30 (TbTh), −0.28 to −0.24 (TbSp), 0.58 to 0.71 (Surface) and 0.12 to 0.16 (<α>), 0.07 to 0.11 (<αz>), −0.44 to −0.30 (σ(α)), and −0.39 to −0.14 (σ(αz)) at the different skeletal sites. The 95% confidence intervals of β overlapped for almost all microstructure parameters at the different skeletal sites. The scaling relations were independent of vertebral fracture status and similar for subjects aged 60–69, 70–79, and >79years. In conclusion, the bone volume fraction–microstructure scaling relations showed a rather universal character.

Glauben als Grundlage - Die Rezeption Michael Polanyis im Gespräch von Theologie und Naturwissenschaften

Das Konzept des „Glaubens“ ist eine zentrale Grundlage von Polanyis Wissenschaftstheorie, und schon früh hat er sich explizit mit dem Verhältnis von Religion und Wissenschaft beschäftigt. Entsprechend wohlwollend ist seine Philosophie im Gespräch von Theologie und Naturwissenschaften aufgenommen worden. Seine deutschsprachige Rezeption blieb dabei bislang recht spärlich, während er in dem angelsächsischen Gespräch der Wissenschaften früh reiche Wirkung entfaltet und nahezu paradigmatische Bedeutung gewonnen hat. Die 2005 erschienene umfangreiche Polanyibiographie von William T. Scott und Martin X. Moleski, S.J. informiert auch über die Facetten von Polanyis eigenen Glauben. Sie stellt damit eine wesentliche Interpretationshilfe da, wie man eine Streitfrage der angelsächsischen Polanyi-Rezeption betreffs der Realität des Gegenstandes der Religion in seiner Philosophie beurteilen kann. Es ist davon auszugehen, dass er mit Tillich den Existenzbegriff in seiner Anwendung auf Gott abgelehnt hat und die Gelwick/Torrance-Prosch-Debatte, die um die Frage der unabhängigen Existenz Gottes in Polanyis Denken kreist, deswegen mehr oder weniger sinnlos ist.

Conservation of threatened habitat types under future climate change – Lessons from plant-distribution models and current extinction trends in southern Germany

A higher risk of future range losses as a result of climate change is expected to be one of the main drivers of extinction trends in vascular plants occurring in habitat types of high conservation value. Nevertheless, the impact of the climate changes of the last 60 years on the current distribution and extinction patterns of plants is still largely unclear. We applied species distribution models to study the impact of environmental variables (climate, soil conditions, land cover, topography), on the current distribution of 18 vascular plant species characteristic of three threatened habitat types in southern Germany: (i) xero-thermophilous vegetation, (ii) mesophilous mountain grasslands (mountain hay meadows and matgrass communities), and (iii) wetland habitats (bogs, fens, and wet meadows). Climate and soil variables were the most important variables affecting plant distributions at a spatial level of 10 × 10 km. Extinction trends in our study area revealed that plant species which occur in wetland habitats faced higher extinction risks than those in xero-thermophilous vegetation, with the risk for species in mesophilous mountain grasslands being intermediary. For three plant species characteristic either of mesophilous mountain grasslands or wetland habitats we showed exemplarily that extinctions from 1950 to the present day have occurred at the edge of the species’ current climatic niche, indicating that climate change has likely been the main driver of extinction. This is largely consistent with current extinction trends reported in other studies. Our study indicates that the analysis of past extinctions is an appropriate means to assess the impact of climate change on species and that vulnerability to climate change is both species- and habitat-specific.