Climatic controls on leaf wax hydrogen isotope ratios in terrestrial and marine sediments along a hyperarid-to-humid gradient

The hydrogen isotope composition of leaf wax biomarkers (δ2Hwax) is a valuable tool for reconstructing continental paleohydrology, since it serves as a proxy for the hydrogen isotope composition of precipitation (δ2Hpre). To yield robust palaeohydrological reconstructions using δ2Hwax in marine archives, it is necessary to examine the impacts of regional climate on δ2Hwax and assess the similarity between marine sedimentary δ2Hwax and the source of continental δ2Hwax. Here, we examined an aridity gradient from hyperarid to humid along the Chilean coast. We sampled sediments at the outlets of rivers draining into the Pacific as well as soils within catchments and marine surface sediments adjacent to the outlets of the studied rivers and analyzed the relationship between climatic variables and δ2Hwax values. We found that apparent fractionation between leaf waxes and source water is relatively constant in humid and semiarid regions (average: −121 ‰). However, it becomes less negative in hyperarid regions (average: −86 ‰) as a result of evapotranspirative processes affecting soil and leaf water 2H enrichment. We also observed that along strong aridity gradients, the 2H enrichment of δ2Hwax follows a non-linear relationship with water content and water flux variables, driven by strong soil evaporation and plant transpiration. Furthermore, our results indicate that δ2Hwax values in marine surface sediments largely reflect δ2Hwax values from the continent, confirming the robustness of marine δ2Hwax records for paleohydrological reconstructions along the Chilean margin. These findings also highlight the importance of considering the effects of hyperaridity in the interpretation of δ2Hwax values and pave the way for more quantitative paleohydrological reconstructions using δ2Hwax

Stromal Hedgehog signalling is downregulated in colon cancer and its restoration restrains tumour growth

A role for Hedgehog (Hh) signalling in the development of colorectal cancer (CRC) has been proposed. In CRC and other solid tumours, Hh ligands are upregulated; however, a specific Hh antagonist provided no benefit in a clinical trial. Here we use Hh reporter mice to show that downstream Hh activity is unexpectedly diminished in a mouse model of colitis-associated colon cancer, and that downstream Hh signalling is restricted to the stroma. Functionally, stroma-specific Hh activation in mice markedly reduces the tumour load and blocks progression of advanced neoplasms, partly via the modulation of BMP signalling and restriction of the colonic stem cell signature. By contrast, attenuated Hh signalling accelerates colonic tumourigenesis. In human CRC, downstream Hh activity is similarly reduced and canonical Hh signalling remains predominantly paracrine. Our results suggest that diminished downstream Hh signalling enhances CRC development, and that stromal Hh activation can act as a colonic tumour suppressor

Stroma-regulated HMGA2 is an independent prognostic marker in PDAC and AAC

Background: The HMGA2 protein has experimentally been linked to EMT and cancer stemness. Recent studies imply that tumour-stroma interactions regulate these features and thereby contribute to tumour aggressiveness. Methods: We analysed 253 cases of pancreatic ductal adenocarcinoma (PDAC) and 155 cases of ampullary adenocarcinoma (AAC) for HMGA2 expression by IHC. The data were correlated with stroma abundance and supplemented by experimental studies. Results: HMGA2 acts as an independent prognostic marker associated with a significantly shorter overall survival in both tumour types. Overall, HMGA2-positivity was more frequent in patients with PDAC than with AAC. The HMGA2 status in tumour cells significantly correlated with the abundance of PDGFRβ-defined stroma cells. In vivo co-injection of Panc-1 cancer cells with pancreatic stellate cells increased tumour growth in a manner associated with increased HMGA2 expression. Furthermore, in vitro treatment of Panc-1 with conditioned media from PDGF-BB-activated stellate cells increased their ability to form tumour spheroids. Conclusions: This study identifies HMGA2 expression in tumour cells as an independent prognostic marker in PDAC and AAC. Correlative data analysis gives novel tissue-based evidence for a heterotypic cross-talk with stroma cells as a possible mechanism for HMGA2 induction, which is further supported by experimental models

Kalign2: high-performance multiple alignment of protein and nucleotide sequences allowing external features

In the growing field of genomics, multiple alignment programs are confronted with ever increasing amounts of data. To address this growing issue we have dramatically improved the running time and memory requirement of Kalign, while maintaining its high alignment accuracy. Kalign version 2 also supports nucleotide alignment, and a newly introduced extension allows for external sequence annotation to be included into the alignment procedure. We demonstrate that Kalign2 is exceptionally fast and memory-efficient, permitting accurate alignment of very large numbers of sequences. The accuracy of Kalign2 compares well to the best methods in the case of protein alignments while its accuracy on nucleotide alignments is generally superior. In addition, we demonstrate the potential of using known or predicted sequence annotation to improve the alignment accuracy. Kalign2 is freely available for download from the Kalign web site (http://msa.sbc.su.se/)

Wirkungen des SGB II auf Personen mit Migrationshintergrund: Projekt IIa1 - 04/06 ; Jahresbericht zum 31.12.2008 - Hauptband

Auf Grundlage von Geschäftsdaten, von repräsentativen telefonischen Befragungen und von qualitativen Interviews mit Betroffenen und Fallmanagern wurden die Wirkungen der "Grundsicherung für Arbeitsuchende" auf Migrant/innen untersucht. Ihr Anteil an allen ALG-II Beziehenden beträgt im bundesweiten Durchschnitt 28 Prozent. Im Vergleich zu denjenigen ohne Migrationshintergrund sind sie im Durchschnitt jünger und haben häufiger keinen, aber auch häufiger höhere (Aus-)Bildungsabschlüsse. Die häufig fehlende Anerkennung ausländischer Abschlüsse wirkt sich auf die Arbeitsmarktchancen ebenso negativ aus wie das Fehlen jeglicher Ausbildung. Migrant/innen erhalten bei den Grundsicherungsstellen im Vergleich zu Deutschen ohne Migrationshintergrund mehr Beratungsgespräche, schließen jedoch seltener Eingliederungsvereinbarungen ab und nehmen seltener an Maßnahmen teil. Einige Herkunftsgruppen werden deutlich häufiger mit Sanktionen belegt, andere Herkunftsgruppen deutlich seltener

Accessing and preserving information:combining ICT4D and archival science to empower marginalized communities

Information and communication technology for development (ICT4D) is a field of research concerned with studying how information and communication technologies (ICTs) can be used to improve the socio-economic situation of marginalized communities in developing countries. The authors identify the preservation of the information provided or accessed during ICT4D projects as a critical gap in ICT4D research. They argue that archival science, an information discipline concerned with the preservation of recorded information, provides theories and models that can help make ICT4D projects more sustainable. They discuss the creation of analog backups by participants in an ICT4D project in Bangladesh as an example of communities taking the initiative to remedy the limitations of an ICT4D project with simple pen and paper technology to preserve the information they wanted to keep. Conversely, they argue that insights on how marginalized communities interact with and preserve information gained through ICT4D projects can enrich archival science and foster the development of more inclusive theories and practices. Finally, they suggest areas for interdisciplinary research between ICT4D and archival science.</p