ALBERT

Description: Relations between climate change and landscape evolution during the last two millennia in southeastern coastal Tunisia have been documented using high-resolution reconstruction of flood history and fire activity in the Sebkha Mhabeul core. The age model, based on tephrochronology, indicates that the core extends from Roman to modern times and encompasses the well-defined climatic periods of the last two millennia. This record provides a first palaeoecological/palaeoclimatic high resolution reconstruction in North Africa using a cross-disciplinary approach with both physical (grey-scale intensity, quartz particles) and biological (charcoal and pollen) indicators. The flood history shows four wet/dry cycles (ca. AD 550–950, 950–1300, 1300–1570 and 1570–1870) of different duration. Major hydrological instabilities are concentrated during the Medieval Climate Anomalies and the early Little Ice Age, between AD 1000 and 1550. Direct correlation between climate and fire cannot be established suggesting that the fire history of the Sebkha environment is mainly influenced by human activity. This study demonstrates the great value of sebkhas as palaeoenvironmental archives.

Description: Total DNA was extracted and purified from luminal digesta samples (1 g) of 14-week-old (c. 43 kg bodyweight) pigs. Digoxigenin (DIG) labelled PCR products of the beta toxin gene of Clostridium perfringens type C were generated with DIG-11-UTP and chemoluminescent signals of DIG-labelled PCR products were detected on slot blots and recorded with a sensitive charge coupled densitometric camera. Detection limit and correlation of chemoluminescent signals to initial target DNA concentration were evaluated. Detection of the beta toxin gene could be achieved with 100 ag C. perfringens DNA in the presence of 1 μg unspecific DNA. The semiquantitative DIG-PCR assay was used to evaluate the relative abundance of the beta toxin gene of C. perfringens type C in purified DNA extracts from intestinal samples of pigs, which were fed a wheat/barley diet (controls), supplemented with the antibiotic avilamycin (40 mg/kg feed), a xylanase (4000 U/kg feed) or a combination of both feed additives. The antibiotic treatment significantly reduced the amount of PCR product in ileal and colon DNA extracts. Xylanase supplementation significantly reduced the amount of PCR product in colon samples, but led to an increase in jejunal samples. From the results it is concluded, that the antibiotic inhibited growth of C. perfringens type C in the ileum and colon of pigs. The semiquantitative DIG-PCR assay can be used to sensitively monitor the relative abundance of specific pathogens in the intestinal tract.

Description: An optimized spectroscopic method combining quantitative evolved gas analysis via Fourier transform infrared spectroscopy (FTIR-EGA) and qualitative in situ thermal reaction monitoring via diffuse reflectance Fourier transform infrared spectroscopy (in situT DRIFTS) is being proposed to rapidly characterize soil organic matter (SOM) to study its dynamics and stability. A thermal reaction chamber coupled with an infrared gas cell was used to study the pattern of thermal evolution of carbon dioxide (CO2) in order to relate evolved gas to different qualities of soil organic matter (SOM). Soil samples were from three different sites, i.e. (i) the Static Fertilization Experiment, Bad Lauchstädt (Chernozem) from treatments of farmyard manure (FYM), mineral fertilizer (NPK), combination (FYM + NPK) and control without fertilizer inputs, and cropped soils from the (ii) Kraichgau and (iii) Swabian Alb (Cambisols) areas, Southwest Germany. Soils from Kraichgau and Swabian Alb were further fractionated into particulate organic matter (POM), sand and stable aggregates (Sa + A), silt and clay (Si + C), and NaOCl oxidized Si + C (rSOC) to gain OM of different inferred stabilities. Fresh soil samples from the Kraichgau and Swabian Alb were incubated at 20 °C and 50% water holding capacity for 490 days in order to measure soil respiration under controlled conditions. A variable long path length gas cell was used to record the mid-infrared absorbance intensity of carbon dioxide (2400 to 2200 cm−1) being evolved during soil heating from 25 to 700 °C with a heating rate of 68 °C min−1 during an initial ramping time of 10 min and holding time of 10 min. Separately the heating chamber was placed in a diffuse reflectance chamber (DRIFTS) for measuring the mid-infrared absorption of the soil sample during heating. Thermal stability of the bulk soils and fractions was measured via the temperature of maximum CO2 (2400 to 2200 cm−1 evolution (CO2). Results indicated that the FYM + NPK and FYM treatments of the Chernozem soils of Bad Lauchstädt had a lower CO2max as compared to both NPK and CON treatments. On average CO2max in Bad Lauchstädt was much higher (447 °C) as compared to the Kraichgau (392 °C) and Swabian Alb (384 °C) sites. The POM fraction had the highest CO2 (477 °C), while rSOC had a first peak at 265 °C at both sites and a second peak at 392 °C for the Swabian Alb and 482 °C for the Kraichgau. The CO2 was found to increase after 490 day incubation, while the C lost during incubation was derived from the whole temperature range but a relatively higher proportion from 200 to 350 °C. In situT DRIFTS measurements indicated decreases in vibrational intensities in the order of C-OH = unknown C vibration

Description: We used differential scanning calorimetry (DSC) to infer thermal properties of soil organic matter (SOM) in the static fertilization experiment in Bad Lauchstädt, Germany, which has been established in 1902. Four treatments (null N, change from null to manuring in 1978 NM, change from manuring to null in 1978 MN, and permanent manure and mineral fertilization since 1902 M) were sampled in 2004. Soil organic carbon contents were highest for M (2.4%), lowest for N (1.7%), and similar for MN and NM (2.2%). DSC thermograms were characterized by three peaks at around 354, 430, and 520°C, which were assigned to as thermally labile and stable SOM and combustion residues from lignite, respectively. DSC peak temperatures were relatively constant among treatments, but peak heights normalized to the organic C content of the soil were significantly different for labile and stable SOM. Labile C was higher for M〉MN=NM=N, and stable C decreased in the order N=NM〉MN=M, showing that agricultural depletion of SOM increases the share of thermally stable C. Lignite-derived C was not affected by management, suggesting a homogeneous deposition across treatments.

Description: We used differential scanning calorimetry (DSC) to infer thermal properties of soil organic matter (SOM) in the static fertilization experiment in Bad Lauchstädt, Germany, which has been established in 1902. Four treatments (null N, change from null to manuring in 1978 NM, change from manuring to null in 1978 MN, and permanent manure and mineral fertilization since 1902 M) were sampled in 2004. Soil organic carbon contents were highest for M (2.4%), lowest for N (1.7%), and similar for MN and NM (2.2%). Three heat flow peaks at around 354°C, 430°C, and 520°C, which were assigned to as thermally labile and stable SOM and combustion residues from lignite, respectively, characterized DSC thermograms. DSC peak temperatures were relatively constant among treatments, but peak heights normalized to the organic C content of the soil were significantly different for labile and stable SOM. Labile C was higher for M〉MN=NM=N, and stable C decreased in the order N=NM〉MN=M, showing that agricultural depletion of SOM increases the share of thermally stable C. Lignite-derived C was not affected by management, suggesting a homogeneous deposition across treatments.

Description: An optimized spectroscopic method combining quantitative evolved gas analysis via Fourier transform infrared spectroscopy (FTIR-EGA) in combination with a qualitative in situ thermal reaction monitoring via diffuse reflectance Fourier transform infrared spectroscopy (in situT DRIFTS) is being proposed to rapidly characterize soil organic matter (SOM) to study its dynamics and stability. A thermal reaction chamber coupled with an infrared gas cell was used to study the pattern of thermal evolution of carbon dioxide (CO2) in order to relate evolved gas (i.e., CO2) to different qualities of SOM. Soil samples were taken from three different arable sites in Germany: (i) the Static Fertilization Experiment, Bad Lauchstädt (Chernozem), from treatments of farmyard manure (FYM), mineral fertilizer (NPK), their combination (FYM + NPK) and control without fertilizer inputs; (ii) Kraichgau; and (iii) Swabian Alb (Cambisols) areas, Southwest Germany. The two latter soils were further fractionated into particulate organic matter (POM), sand and stable aggregates (Sa + A), silt and clay (Si + C), and NaOCl oxidized Si + C (rSOC) to gain OM of different inferred stabilities; respiration was measured from fresh soil samples incubated at 20 °C and 50% water holding capacity for 490 days. A variable long path length gas cell was used to record the mid-infrared absorbance intensity of CO2 (2400 to 2200 cm−1) being evolved during soil heating from 25 to 700 °C with a heating rate of 68 °C min−1 and holding time of 10 min at 700 °C. Separately, the heating chamber was placed in a diffuse reflectance chamber (DRIFTS) for measuring the mid-infrared absorbance of the soil sample during heating. Thermal stability of the bulk soils and fractions was measured via the temperature of maximum CO2 evolution (CO2max). Results indicated that the FYM + NPK and FYM treatments of the Chernozem soils had a lower CO2max as compared to both NPK and CON treatments. On average, CO2max of the Chernozem was much higher (447 °C) as compared to the Cambisol sites (Kraichgau 392 °C; Swabian Alb 384 °C). The POM fraction had the highest CO2max (477 °C), while rSOC had a first peak at 265 °C at both sites and a second peak at 392 °C for the Swabian Alb and 482 °C for the Kraichgau. The CO2max increased after 490 day incubation, while the C lost during incubation was derived from the whole temperature range but a relatively higher proportion from 200 to 350 °C. In situT DRIFTS measurements indicated decreases in vibrational intensities in the order of C-OH = unknown C vibration 〈 C-H 〈 −COO/C =C 〈 C = C with increasing temperature, but interpretation of vibrational changes was complicated by changes in the spectra (i.e., overall vibrational intensity increased with temperature increase) of the sample during heating. The relative quality changes and corresponding temperatures shown by the in situT DRIFTS measurements enabled the fitting of four components or peaks to the evolved CO2 thermogram from the FTIR-EGA measurements. This gave a semi-quantitative measure of the quality of evolved C during the heating experiment, lending more evidence that different qualities of SOM are being evolved at different temperatures from 200 to 700 °C. The CO2max was influenced by long-term FYM input and also after 490 days of laboratory incubation, indicating that this measurement is an indicator for the relative overall SOM stability. The combination of FTIR-EGA and in situT DRIFTS allows for a quantitative and qualitative monitoring of thermal reactions of SOM, revealing its relative stability, and provides a sound basis for a peak fitting procedure for assigning proportions of evolved CO2 to different thermal stability components.

Description: The Interleaved Frequency Division Multiple Access (IFDMA) scheme is a candidate for next generation mobile radio systems. IFDMA is based on compression, repetition and subsequent user dependent frequency shift of a modulated signal. As in OFDMA, multiple access is enabled by the assignment of overlapping but mutually orthogonal subcarriers to each user. It provides various advantages such as low peak to average power ratio, orthogonality of the signals of different users even for transmission over a time dispersive channel and low complexity. However, IFDMA is sensitive to frequency offsets. In this paper, a derivation of IFDMA based on a generalised OFDMA signal model with specific precoding and specific subcarrier allocation is presented. Moreover, simulation results showing the robustness properties of IFDMA against frequency errors are given.