Nitrogen Gain and Loss Along an Ecosystem Sequence: From Semi-desert to Rainforest

Plants and microorganisms, besides the climate, drive nitrogen (N) cycling in ecosystems. Our objective was to investigate N losses and N acquisition strategies along a unique ecosystem-sequence (ecosequence) ranging from arid shrubland through Mediterranean woodland to temperate rainforest. These ecosystems differ in mean annual precipitation, mean annual temperate, and vegetation cover, but developed on similar granitoid soil parent material, were addressed using a combination of molecular biology and soil biogeochemical tools. Soil N and carbon (C) contents, δ15N signatures, activities of N acquiring extracellular enzymes as well as the abundance of soil bacteria and fungi, and diazotrophs in bulk topsoil and rhizosphere were determined. Relative fungal abundance in the rhizosphere was higher under woodland and forest than under shrubland. This indicates toward plants' higher C investment into fungi in the Mediterranean and temperate rainforest sites than in the arid site. Fungi are likely to decompose lignified forest litter for efficient recycling of litter-derived N and further nutrients. Rhizosphere—a hotspot for the N fixation—was enriched in diazotrophs (factor 8 to 16 in comparison to bulk topsoil) emphasizing the general importance of root/microbe association in N cycle. These results show that the temperate rainforest is an N acquiring ecosystem, whereas N in the arid shrubland is strongly recycled. Simultaneously, the strongest 15N enrichment with decreasing N content with depth was detected in the Mediterranean woodland, indicating that N mineralization and loss is highest (and likely the fastest) in the woodland across the continental transect. Higher relative aminopeptidase activities in the woodland than in the forest enabled a fast N mineralization. Relative aminopeptidase activities were highest in the arid shrubland. The highest absolute chitinase activities were observed in the forest. This likely demonstrates that (a) plants and microorganisms in the arid shrubland invest largely into mobilization and reutilization of organically bound N by exoenzymes, and (b) that the ecosystem N nutrition shifts from a peptide-based N in the arid shrubland to a peptide- and chitin-based N nutrition in the temperate rainforest, where the high N demand is complemented by intensive N fixation in the rhizosphere

Since 2015 the SinoGerman research project SIGN supports water quality improvement in the Taihu region, China

The Taihu (Tai lake) region is one of the most economically prospering areas of China. Due to its location within this district of high anthropogenic activities, Taihu represents a drastic example of water pollution with nutrients (nitrogen, phosphate), organic contaminants and heavy metals. High nutrient levels combined with very shallow water create large eutrophication problems, threatening the drinking water supply of the surrounding cities. Within the international research project SIGN (SinoGerman Water Supply Network, www.water-sign.de), funded by the German Federal Ministry of Education and Research (BMBF), a powerful consortium of fifteen German partners is working on the overall aim of assuring good water quality from the source to the tap by taking the whole water cycle into account: The diverse research topics range from future proof strategies for urban catchment, innovative monitoring and early warning approaches for lake and drinking water, control and use of biological degradation processes, efficient water treatment technologies, adapted water distribution up to promoting sector policy by good governance. The implementation in China is warranted, since the leading Chinese research institutes as well as the most important local stakeholders, e.g. water suppliers, are involved

Effects of Personalized Banner Ads on Visual Attention and Recognition Memory

Internet companies collect a vast amount of data about their users in order to personalize banner ads. However, very little is known about the effects of personalized banners on attention and memory. In the present study, 48 subjects performed search tasks on web pages containing personalized or nonpersonalized banners. Overt attention was measured by an eye-tracker, and recognition of banner and task-relevant information was subsequently examined. The entropy of fixations served as a measure for the overall exploration of web pages. Results confirm the hypotheses that personalization enhances recognition for the content of banners while the effect on attention was weaker and partially nonsignificant. In contrast, overall exploration of web pages and recognition of task-relevant information was not influenced. The temporal course of fixations revealed that visual exploration of banners typically proceeds from the picture to the logo and finally to the slogan. We discuss theoretical and practical implications. Copyright (c) 2014 John Wiley & Sons, Ltd

Auditory Information Supports the Learning Transfer from L2 to L3 Tonal Languages

While the acquisition of three or more languages becomes steadily more important in modern societies, the underlying cognitive and linguistic processes of multi-linguistic language acquisition are not well understood. This study investigates how a formerly acquired second language (L2) can facilitate the acquisition of a third language (L3). Thirty-two native German speakers with proficient knowledge in either a tonal L2 (Chinese) or a non-tonal L2 (English) learned vocabulary of a tonal L3 (Thai), while the information of the target L3 was either presented visually or both visually and auditorily. Additional auditory information improved later recognition of L3 vocabulary for participants with a tonal L2 (Chinese) but not for those with a non-tonal L2 (English). These results suggest that the L2 to L3 learning transfer can be improved when the similarities between both languages, such as tonal information, are accentuated in the learning process

Different Responses to Drug Safety Screening Targets between Human Neonatal and Infantile Heart Tissue and Cardiac Bodies Derived from Human-Induced Pluripotent Stem Cells

Aims. Induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) have become a promising tool in cardiovascular safety pharmacology. Immaturity of iPS-CMs remains an ongoing concern. We compared electrophysiological and contractile features of cardiac bodies (hiPS-CBs) derived from human-induced pluripotent stem cells and human neonatal and infantile myocardial slices relevant for drug screening. Methods and Results. Myocardial tissue slices were prepared from biopsies obtained from patients undergoing surgery for hypoplastic left heart syndrome (HLHS) and tetralogy of Fallot (TOF). Electrophysiological features and response to I-k,I-r blockade as well as contractile properties were investigated using microelectrodes and isometric force measurements and were compared to hiPS-CBs. Both native myocardial tissue slices as well as hiPS-CBs showed action potential prolongation after I-k,I-r blockade, but early afterdepolarisations could be observed in native myocardial tissue slices only. The force-frequency relationship (FFR) varied at lower frequencies and was negative throughout at higher frequencies in hiPS-CBs. In contrast, native myocardial tissue slices exhibited positive, negative, and biphasic FFRs. In contrast to native myocardial tissue slices, hiPS-CBs failed to show an inotropic response to ss-adrenergic stimulation. Although all groups showed ss-adrenergic induced positive lusitropy, the effect was more pronounced in myocardial tissue slices. Conclusion. hiPS-CBs were able to reproduce AP prolongation after I-k,I-r blockade, but to a lesser extent compared to human neonatal and infantile myocardial tissue slices. Early afterdepolarisations could not be induced in hiPS-CBs. Contractile force was differently regulated by -adrenergic stimulation in hiPS-CBs and the native myocardium. If used for cardiotoxicity screening, caution is warranted as hiPS-CBs might be less sensitive to pharmacologic targets compared to the native myocardium of neonates and infants

Effects of drying/rewetting on soil aggregate dynamics and implications for organic matter turnover

Drying and rewetting (D/W) of soil have significant impacts on soil organic matter (SOM) turnover. We hypothesised that frequent D/W cycles would release the labile organic matter locked away in soil aggregates, increasing the priming effect (PE) (acceleration or retardation of SOM turnover after fresh substrate addition) due to preferential utilisation by microbes. C-13-labelled lignocellulose was added to the soil, and the effects of 0, 1, or 4 cycles of D/W were evaluated at 5 degrees C and 25 degrees C after a 27-day incubation of undisturbed soil cores from a temperate forest (Araucaria araucana). Following the incubation, macroaggregates (> 250 mu m), microaggregates (250-53 mu m), and silt + clay materials ( 2.0 g cm(-3)) were determined. D/W cycles caused macroaggregates to increase and a decrease in microaggregates (> 15%) at warm temperatures, and preferential use of the novel particulate organic matter (C-13 labelled), formerly protected fPOM. CO2 efflux was three times higher at 25 degrees C than at 5 degrees C. The D/W cycles at 25 degrees C had a strong negative impact on cumulative CO2 efflux, which decreased by approximately - 30%, induced by a negative PE of -50 mg C kg(-1) soil with 1 D/W cycle and - 100 mg C kg(-1) soil with 4 D/W cycles, relative to soil under constant soil moisture receiving C-13-labelled lignocellulose, but no cycles. Increasing the temperature and the number of D/W cycles caused a decrease in substrate use efficiency of particulate lignocellulose. In conclusion, D/W cycles at warm temperatures accelerated OM turnover due to preferential use from fPOM, increasing macroaggregates at the expense of microaggregates. A novel pathway of OM release and PE due to the D/W cycles is discussed.German Research Foundation (DFG) SPP-1803 KU 1184/36-1 CONICYT of Chilean government 21160957 National Commission of Research of Science and Technology FONDECYT 1170119 Network for Extreme Environmental Research (NEXER), Universidad de La Fronter

Element contents and stable isotope analysis in plants from a nitrogen and potassium tracer experiment in the Chilean Coastal Cordillera

A tracer experiment was conducted in three study sites along a continental transect from arid to humid-temperate conditions in the Chilean Coastal Cordillera. The objective was to determine the short-term (<1 year) plant nitrogen (N) and potassium (K) acquisition from topsoil (A-Bw horizons), subsoil (Bw-BCw horizons), and saprolite (below BCw horizon). In February and March 2016, δ¹⁵N (as Na¹⁵NO₃, 99 at%) and the K analogs rubidium (as RbCl) and cesium (as CsCl) were injected in three soil depths around the focal plants: Gutierrezia resinosa (H.&A.) B. in the northernmost site (arid shrubland), Aristeguietia salvia (C.) K.&R. in the intermediate site (mediterranean woodland), and Araucaria araucana (M.) K. in the southernmost site (temperate rainforest). The injection holes were drilled with an auger and the excavated soil material was collected to determine soil N, K, Rb, and Cs contents. In November 2016, shoot and root material of labeled and unlabeled plants was collected. The N, K, Rb, and Cs contents and the stable isotope ratios of N (expressed as δ¹⁵N) in plant tissue were measured. The tracer recovery by plants was determined by the δ¹⁵N enrichment and the shift of Rb and Cs contents normalized to the K content between reference plants and labeled plants.The data set contains the N, K, Rb, and Cs contents as well as the stable isotope ratios of N in plant biomass

Potassium, rubidium, and cesium contents in soil along a continental transect in the Chilean Coastal Cordillera

A tracer experiment was conducted in three study sites along a continental transect from arid to humid-temperate conditions in the Chilean Coastal Cordillera. The objective was to determine the short-term (<1 year) plant nitrogen (N) and potassium (K) acquisition from topsoil (A-Bw horizons), subsoil (Bw-BCw horizons), and saprolite (below BCw horizon). In February and March 2016, ¹⁵N (as Na¹⁵NO₃, 99 at%) and the K analogs rubidium (as RbCl) and cesium (as CsCl) were injected in three soil depths around the focal plants: Gutierrezia resinosa (H.&A.) B. in the northernmost site (arid shrubland), Aristeguietia salvia (C.) K.&R. in the intermediate site (mediterranean woodland), and Araucaria araucana (M.) K. in the southernmost site (temperate rainforest). The injection holes were drilled with an auger and the excavated soil material was collected to determine soil N, K, Rb, and Cs contents. In November 2016, shoot and root material of labeled and unlabeled plants was collected. The N, K, Rb, and Cs contents and the stable isotope ratios of δ¹⁵N (expressed as δ¹⁵N) in plant tissue were measured. The tracer recovery by plants was determined by the ¹⁵N enrichment and the shift of Rb and Cs contents normalized to the K content between reference plants and labeled plants. The data set contains the K, Rb, and Cs contents in soil

Effect of annealing and cobalt content on relaxation and crystallization behavior of zirconium based bulk metallic glasses

The effects of annealing and cobalt content on relaxation and the crystallization process of Zr64Ni10Al7Cu19 bulk metallic glasses were investigated. β-relaxation occurs during annealing, leading to increased endotherm before crystallization. α-relaxation during high temperature annealing (higher than Tg) affects the crystallization process. The introduction of cobalt leads to an inhomogeneous amorphous structure and two-step crystallization due to the positive mixing enthalpy between cobalt and copper. Non-affine thermal strain arising from low temperature annealing of heterogeneous structure leads to a reduced endotherm phenomenon during relaxation on the DSC curves and a reduction in hardness

Mesenchymal Stem Cells and Their Conditioned Medium Improve Integration of Purified Induced Pluripotent Stem Cell-Derived Cardiomyocyte Clusters into Myocardial Tissue

Induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) might become therapeutically relevant to regenerate myocardial damage. Purified iPS-CMs exhibit poor functional integration into myocardial tissue. The aim of this study was to investigate whether murine mesenchymal stem cells (MSCs) or their conditioned medium (MScond) improves the integration of murine iPS-CMs into myocardial tissue. Vital or nonvital embryonic murine ventricular tissue slices were cocultured with purified clusters of iPS-CMs in combination with murine embryonic fibroblasts (MEFs), MSCs, or MScond. Morphological integration was assessed by visual scoring and functional integration by isometric force and field potential measurements. We observed a moderate morphological integration of iPS-CM clusters into vital, but a poor integration into nonvital, slices. MEFs and MSCs but not MScond improved morphological integration of CMs into nonvital slices and enabled purified iPS-CMs to confer force. Coculture of vital slices with iPS-CMs and MEFs or MSCs resulted in an improved electrical integration. A comparable improvement of electrical coupling was achieved with the cell-free MScond, indicating that soluble factors secreted by MSCs were involved in electrical coupling. We conclude that cells such as MSCs support the engraftment and adhesion of CMs, and confer force to noncontractile tissue. Furthermore, soluble factors secreted by MSCs mediate electrical coupling of purified iPS-CM clusters to myocardial tissue. These data suggest that MSCs may increase the functional engraftment and therapeutic efficacy of transplanted iPS-CMs into infarcted myocardium