Detecting successional changes in long-term empirical data from subalpine conifer forests

In many mountain regions, traditional agriculture and forestry are no longer economically viable and less intense land-use is becoming more and more widespread. Thus, the importance of understanding secondary succession in these abandoned systems increases. This study is based on a comparison of historic (1957) and present tree data (2001) from subalpine forest stands located in the Swiss National Park (SNP), where all management was stopped in 1914. The two data sets contain information on tree and sapling density as well as diameter distribution for all tree species present. Using time-series analyses, space for time substitution and multivariate methods (PCoA, minimum spanning tree analysis), we investigated if successional changes can be detected within the forest stands in the SNP. Our results showed that the stands studied are developing from a stage dominated by mountain pine (Pinus montana Miller) to a late successional stage dominated by Swiss stone pine (Pinus cembra L.) and European larch (Larix decidua Miller). This shift in species composition, which was observed in both the tree and sapling layer, was accompanied by a significant decrease in tree density (stems/ha). We also found that stand disturbances, such as fungal diseases, parasitic insects, ungulate browsing, windthrow or snow pressure, have not prevented succession from mountain pine to Swiss stone pine-larch communities. The minimum spanning tree analysis revealed that the sixteen observed 44-year-time-series cover at least 110 years of succession. This time frame is the shortest possible duration for a successional development starting from a 95 to 125-year-old mountain pine stand. The successional changes depicted in our study indicate how similar areas in the Central European Alps might develop in the near future when management cease

Struktur und Langzeitentwicklung von subalpinen Pinus montana Miller und Pinus cembra L. Wäldern in den zentraleuropäischen Alpen

Summary:: Since traditional agriculture and forestry are no longer economically viable in many regions of the European Alps, subalpine forests will become less managed or completely abandoned in the near future. Therefore, the interest in understanding how forest stands will develop after abandonment has increased considerably over the past two decades. While much is known about stand structure and stand development of Norway spruce (Picea abies L.) forests, almost no knowledge is available about the same processes in forest communities of the Central Alps. In the Swiss National Park (SNP), the forested area is comprised of mountain pine (Pinus montana Miller), Swiss stone pine/larch, (Pinus cembra L./Larix decidua L.). and mixed stands. When the Park was founded in 1914 all management activities were stopped. Therefore, this area offers the opportunity to study stand development and changes in stand structure after abandonment. We compared historic (1957) and present data (2001/02) from 19 stands that were grouped into characteristic stand types: "mountain pine”, "mixed”, and "stone pine”. We detected significant decreases in total tree density (stem/ha) and sapling density (saplings/ha) of 45 to 57%, and 64 to 76%, respectively, over the 45 years of observation for all stand types. These changes were strongly related to decreases in the number of shade intolerant mountain pine trees. Simultaneously, the amount of non-standing woody residue increased from less than 4 t/ha to 36 to67.7 t/ha, and the density of standing dead wood (stems/ha) decreased significantly between 72 and 94%. The biomass of standing dead wood (t/ha), however, changed only slightly between 1957 and 01/02. Our results describe the successional development of continental subalpine forests after abandonment and outlines changes that might take place in similar areas in the near futur

In-situ real-time monitoring of spurious modes in HE11_{11} transmission lines using multi-hole couplers in miter bends

Transmission of high-power millimeter waves for ECRH is often realised with oversized corrugated circular waveguides. Coupling from the gyrotron source to the waveguide is typically done via matching mirrors in free space. Small alignment errors of the system lead to the excitation of higher-order modes inside the waveguide beside the main transmission mode HE$_{11}$. Tose modes have comparably higher losses and can in worst case result in local fields exceeding the breakdown limit of the medium inside the waveguide. For alignment control over the whole pulse duration of the gyrotron, a set of hole-array couplers placed into a miter bend mirror probes the field inside the waveguide. The arrays are designed to detect the marker modes for beam offset and tilt (LP$^{(e=0)}$$_{11}$) as well as for beam waist mismatch (LP$_{02}$). In addition, a main mode coupler sensitive mostly for the HE$_{11}$ content is used as a power monitor. By maximizing the signal of the power monitor and minimizing the content of marker modes, a first-order optimization of the coupling from free space to the waveguide can be achieved. Signal processing of the 140 GHz information is done at kHz range after downmixing, using a frequency shifted part of the power monitor signal. As the measurement system is placed in a miter bend mirror, it can also be easily installed at various locations along the transmission line to check for possible misalignments of the waveguide connections between miter bends. Simulation and low power experimental results will be shown

Yersinia enterocolitica exploits different pathways to accomplish adhesion and toxin injection into host cells.

The current paradigm suggests that Yersinia enterocolitica (Ye) adheres to host cells via the outer membrane proteins Yersinia adhesin A (YadA) or invasin (Inv) to facilitate injection of Yops by the type III secretion system. In this process Inv binds directly to β1 integrins of host cells while YadA may bind indirectly via extracellular matrix proteins to β1 integrins. Here we challenged this paradigm and investigated the requirements for Yop injection. We demonstrate that Inv- but not YadA-mediated adhesion depends on β1 integrin binding and activation, and that tight adhesion is a prerequisite for Yop injection. By means of novel transgenic cell lines, shRNA approaches and RGD peptides, we found that YadA, in contrast to Inv, may use a broad host cell receptor repertoire for host cell adhesion. In the absence of β1 integrins, YadA mediates Yop injection by interaction with αV integrins in cooperation with yet unknown cofactors expressed by epithelial cells, but not fibroblasts. Electron microscopic and flow chamber studies revealed that a defined intimate contact area between Ye and host cells resulting in adhesion forces resisting shear stress is required for Yop injection. Thus, the indirect binding of YadA to a broad extracellular matrix (ECM) binding host cell receptor repertoire of different cell types makes YadA a versatile tool to ensure Yop injection. In conclusion, given the differential expression of the outer membrane proteins Inv and YadA in the course of Ye infection and differential expression of integrins by various host cell populations, the data demonstrate that Ye is flexibly armed to accomplish Yop injection in different host cell types, a central event in its immune evasion strategy

Age and gender specific estimation of visceral adipose tissue amounts from radiological images in morbidly obese patients OPEN

Best predictions were found at intervertebral spaces L3-L4 for females (σ 5 = 688 ml, σ 1 = 832 ml) and L1-L2 for males (σ 5 = 846 ml, σ 1 = 992 ml), irrespective of age. In conclusion, VAT volumes in morbidly obese patients can be reliably predicted by multiplying the segmented VAT area at a gender-specific lumbar reference level with a fixed scaling factor and effective slice thickness. Obesity is a worldwide increasing healthcare problem. In the United States, for example, over two thirds of the adult population are either overweight (33%, BMI: 25-30 kg/m 2 ), obese (35%, 30-40 kg/m 2 ) or morbidly obese (6%, > 40 kg/m 2 ) 1 . While prevalence of obesity is still rising, in particular the morbid form 2 , more and more is known about its association with an increased overall mortality, often caused by cardiovascular diseases, diabetes or hypertension Quantification of abdominal VAT volumes by cross-sectional imaging, typically by computed tomography (CT) or magnetic resonance imaging (MRI), however, is generally time-consuming 7-9 . Various methods have already been proposed to estimate total VAT volumes from simple measurements on a limited number of slices. Studies using single or five slice VAT areas for VAT volume prediction have mainly focused on patients with BMI values below 40 kg/m 2 and data for the morbidly obese are lackin

Patterns and universals of mate poaching across 53 nations : the effects of sex, culture, and personality on romantically attracting another person’s partner

As part of the International Sexuality Description Project, 16,954 participants from 53 nations were administered an anonymous survey about experiences with romantic attraction. Mate poaching--romantically attracting someone who is already in a relationship--was most common in Southern Europe, South America, Western Europe, and Eastern Europe and was relatively infrequent in Africa, South/Southeast Asia, and East Asia. Evolutionary and social-role hypotheses received empirical support. Men were more likely than women to report having made and succumbed to short-term poaching across all regions, but differences between men and women were often smaller in more gender-egalitarian regions. People who try to steal another's mate possess similar personality traits across all regions, as do those who frequently receive and succumb to the poaching attempts by others. The authors conclude that human mate-poaching experiences are universally linked to sex, culture, and the robust influence of personal dispositions.peer-reviewe

Die gegenwärtige Bedeutung des mathematisch-physikalischen Unterrichts an Gymnasien

von Harald SchützProgr.-Nr. 36