Hydrogeology of an alpine rockfall aquifer system and its role in flood attenuation and maintaining baseflow

The frequency and intensity of extreme hydrological events in Alpine regions is projected to increase with climate change. The goal of this study is to better understand the functioning of aquifers composed of complex alluvial and rockfall deposits in Alpine valleys and to quantify the role of these natural storage spaces in flood attenuation and baseflow maintenance. Geomorphological and hydrogeological mapping, tracer tests, and continuous flow measurements were conducted in the Reintal (German Alps), where runoff from a karst spring infiltrates a series of postglacial alluvial/rockfall aquifers. During high-flow conditions, groundwater velocities of 30 m h⁻¹ were determined along 500 m; hydrograph analyses revealed short lag times (5 h) between discharge peaks upstream and downstream from the aquifer series; the maximum discharge ratio downstream (22) and the peak recession coefficient (0.196 d⁻¹) are low compared with other Alpine catchments. During low-flow conditions, the underground flow path length increased to 2 km and groundwater velocities decreased to 13 m h⁻¹. Downstream hydrographs revealed a delayed discharge response after 101 h and peaks damped by a factor of 1.5. These results indicate that alluvial/rockfall aquifers might play an important role in the flow regime and attenuation of floods in Alpine regions

Heterogeneous and opportunistic wireless networks

Recent years have witnessed the evolution of a large plethora of wireless technologies with different characteristics, as a response of the operators' and users' needs in terms of an efficient and ubiquitous delivery of advanced multimedia services. The wireless segment of network infrastructure has penetrated in our lives, and wireless connectivity has now reached a state where it is considered to be an indispensable service as electricity or water supply. Wireless data networks grow increasingly complex as a multiplicity of wireless information terminals with sophisticated capabilities get embedded in the infrastructure. © 2012 Springer Milan. All Right Reserved

Channel morphodynamics on a small proglacial braid plain (Fagge River, Gepatschferner, Austria)

Braid plains are important sediment stores in high mountains, particularly in the glacier forefields of Alpine glaciers. Proglacial braid plains receive sediment input from glacial meltwater and proglacial sediment sources like moraines and glacio-fluvial deposits. The channel morphodynamics on the braid plains are strongly related to the sediment transport and flow regime of the proglacial river. This study deals with channel morphodynamics on a small proglacial braid plain in the European Alps. It focuses on two different time scales. Decadal channel planform changes were assessed by remote sensing approaches. The recent channel bed changes were investigated by cross-sectional surveys and particle counts in 2013. This study is part of the DFG/FWF funded interdisciplinary research project PROSA (High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps)

Receiver-based compensation of transmitter-incurred nonlinear distortion in multiple-antenna OFDM systems

To enable an efficient implementation of multiple-antenna OFDM systems, this paper proposes an approach to reduce the influence of transmitter-induced nonlinearities in such systems. The approach comprises a preamble design, an estimation method and a digital compensation algorithm. Correction for the nonlinearities of the different transmitter branches is applied in the receiver, which requires no extra hardware. A numerical performance evaluation shows that the proposed approach can successfully be applied with minimal performance degradation compared to non-impaired systems

Geographica Helvetica / Spatial and temporal variability of sediment transfer and storage in an Alpine basin (Reintal valley, Bavarian Alps, Gemany)

This paper focuses in particular on clastic sediment fluxes on talus slopes. Using orthophoto interpretation, field measurements and GIS-techniques, a quantification of areas and volumes of active sediment transfer related to specific landform units was achieved for different spatial scales. Closer investigation of a single landform complex, more specifically a talus sheet/ debris cone-complex, brought to light that remobilisation can overbalance sediment input by a factor of 57. This could be an indication of what may be expected in the whole catchment. At present. approximately 9% of the research area (3 km2), comprising talus slopes and valley bottom, is characterised by sediment transfer mainly through gravilational and fluvial processes. A comparison of the vast volumes (117.174 m3) derived from these active areas of recent sediment transfer and the volume of the entire valley fill (0.07 km3) indicates, however, that the largest part must be related to remobilised sediments and cannot be considered as sediment input from the adjacent rockwalls. This conclusion is also supported by direct measurements of sediment input.(VLID)221354

An Ultra-Low Power 28nm FD-SOI Low Noise Amplifier based on Channel Aware Receiver System Analysis

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