Time filter

Source Type

Hortnagl L.,University of Innsbruck | Hortnagl L.,ETH Zurich | Wohlfahrt G.,University of Innsbruck | Wohlfahrt G.,European Academy of Bolzano
Biogeosciences | Year: 2014

The methane (CH4) and nitrous oxide (N2O) exchange of a temperate mountain grassland near Neustift, Austria, was measured during 2010-2012 over a time period of 22 months using the eddy covariance method. Exchange rates of both compounds at the site were low, with 97% of all half-hourly CH4 and N2O fluxes ranging between ±200 and ±50 ngm-2 s-1, respectively. The meadow acted as a sink for both compounds during certain time periods, but was a clear source of CH4 and N2O on an annual timescale. Therefore, both gases contributed to an increase of the global warming potential (GWP), effectively reducing the sink strength in terms of CO2 equivalents of the investigated grassland site. In 2011, our best guess estimate showed a net greenhouse gas (GHG) sink of -32 g CO2 equ. m-2 yr-1 for the meadow, whereby 55% of the CO2 sink strength of -71 g CO2 m-2 yr-1 was offset by CH4 (N2O) emissions of 7 (32) g CO2 equ. m-2 yr-1. When all data were pooled, the ancillary parameters explained 27 (42)% of observed CH4 (N2O) flux variability, and up to 62 (76)% on shorter timescales in-between management dates. In the case of N2O fluxes, we found the highest emissions at intermediate soil water contents and at soil temperatures close to 0 or above 14°C. In comparison to CO2, H2O and energy fluxes, the interpretation of CH4 and N2O exchange was challenging due to footprint heterogeneity regarding their sources and sinks, uncertainties regarding post-processing and quality control. Our results emphasize that CH4 and N2O fluxes over supposedly well-aerated and moderately fertilized soils cannot be neglected when evaluating the GHG impact of temperate managed grasslands. © Author(s) 2014.

Janko M.,Ludwig Maximilians University of Munich | Zink A.,Ludwig Maximilians University of Munich | Zink A.,European Academy of Bolzano | Gigler A.M.,Ludwig Maximilians University of Munich | And 2 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2010

Skin protects the body from pathogens and degradation. Mummified skin in particular is extremely resistant to decomposition. External influences or the action of micro-organisms, however, can degrade the connective tissue and lay the subjacent tissue open. To determine the degree of tissue preservation in mummified human skin and, in particular, the reason for its durability, we investigated the structural integrity of its main protein, type I collagen. We extracted samples from the Neolithic glacier mummy known as 'the Iceman'. Atomic force microscopy (AFM) revealed collagen fibrils that had characteristic banding patterns of 69±5 nm periodicity. Both the microstructure and the ultrastructure of dermal collagen bundles and fibrils were largely unaltered and extremely well preserved by the natural conservation process. Raman spectra of the ancient collagen indicated that there were no significant modifications in the molecular structure. However, AFM nanoindentation measurements showed slight changes in the mechanical behaviour of the fibrils. Young's modulus of single mummified fibrils was 4.1±1.1 GPa, whereas the elasticity of recent collagen averages 3.2±1.0 GPa. The excellent preservation of the collagen indicates that dehydration owing to freeze-drying of the collagen is the main process in mummification and that the influence of the degradation processes can be addressed, even after 5300 years. © 2010 The Royal Society.

Lodde M.,General Hospital of Bolzano | Mian C.,General Hospital of Bolzano | Mayr R.,General Hospital of Bolzano | Comploj E.,General Hospital of Bolzano | And 6 more authors.
International Journal of Urology | Year: 2014

Objective: To test the prognostic value of multicolor fluorescence in situ hybridization analyses of tumor cells in urine for prediction of the recurrence and progression of tumor in patients with intermediate risk non-muscle invasive bladder cancer. Methods: A total of 168 patients with non-muscle invasive bladder cancerwere included in the study. Fluorescence in situ hybridization was carried out on the bladder wash urine collected before resection. Tumors were classified as low molecular grading if they had a diploid chromosomal pattern or only a loss of p16 or ch3 aneuploidy, and as high molecular grading if they showed aneuploidy of ch7 or 17. Cox regression models assessed the added prognostic value of fluorescence in situ hybridization for primary tumor recurrence or progression, respectively. Results: Median follow up was 67 months. A total of 57% of tumors were classified as low molecular grading. The 2- and 5-year recurrence-free survival was 68% and 49% for low molecular grading, and 47% and 30% for high molecular grading, respectively. The 2- and 5-year progression-free survival was 95% and 84% for low molecular grading, and 79% and 58% for high molecular grading tumor patients, respectively. Molecular grading (hazard ratio 1.60; P = 0.03) was associated with recurrence, when also accounting for histopathology and a patient's characteristics. Both cancer severity score (hazard ratio 1.51; P < 0.01) and molecular grading (hazard ratio 2.53; P < 0.01) independently and positively predicted progression in multivariable models. The C-index for predicting recurrence increased from 0.58 to 0.61 when molecular grading fluorescence in situ hybridization was included in the model, and from 0.68 to 0.72 when predicting progression. Conclusions: Fluorescence in situ hybridization-based molecular grading increases the accuracy of a prognostic model, predicting both recurrence and progression in patients with intermediate risk non-muscle invasive bladder cancer. © 2014 The Japanese Urological Association.

Wohlfahrt G.,University of Innsbruck | Tasser E.,European Academy of Bolzano
International Journal of Biometeorology | Year: 2015

We present a mobile device for the quantification of the small-scale (a few square meters) spatial variability in the surface energy balance components and several auxiliary variables of short-statured (<1 m) canopies. The key element of the mobile device is a handheld four-component net radiometer for the quantification of net radiation, albedo and infrared surface temperature, which is complemented with measurements of air temperature, wind speed, soil temperature and soil water content. Data are acquired by a battery-powered data logger, which is mounted on a backpack together with the auxiliary sensors. The proposed device was developed to bridge between the spatial scales of satellite/airborne remote sensing and fixed, stationary tower-based measurements with an emphasis on micrometeorological, catchment hydrological and landscape–ecological research questions. The potential of the new device is demonstrated through four selected case studies, which cover the issues of net radiation heterogeneity within the footprint of eddy covariance flux measurements due to (1) land use and (2) slope and aspect of the underlying surface, (3) controls on landscape-scale variability in soil temperature and albedo and (4) the estimation of evapotranspiration based exclusively on measurements with the mobile device. © 2014, The Author(s).

Wohlfahrt G.,University of Innsbruck | Wohlfahrt G.,European Academy of Bolzano | Gu L.,Oak Ridge National Laboratory
Plant, Cell and Environment | Year: 2015

Gross photosynthesis is a key term in plant biology and carbon cycle science, however has been used with different meanings by different communities We review the history of this term and associated concepts to clarify the terminology and make recommendations about a consistent use of terms in accordance with photosynthetic theory. We show that a widely used eddy covariance CO2 flux partitioning approach yields estimates which are quantitatively closer to the definition of true photosynthesis despite aiming at estimating apparent photosynthesis. © 2015 John Wiley & Sons Ltd.

Discover hidden collaborations