Kolloidale Nanokristalle in epitaktischen Halbleiterstrukturen

von Christof ArensPaderborn, Univ., Diss., 200

Global climate

This report lays out the major developments in Durban and assesses the main outcomes. It is structured along the Bali roadmap for a future climate agreement that was agreed at the Bali climate conference in 2007. The Bali roadmap comprises negotiations under two tracks. First, the Ad Hoc Working Group on Further Commitments by Annex I Countries under the Kyoto Protocol (AWG-KP), established at the conference in Montreal in 2005, has been negotiating future emission targets for developed countries (listed in Annex I of the United Framework Convention on Climate Change (UNFCCC) and hence called Annex I countries). As the Kyoto Protocol's first commitment period expires in 2012, the AWG-KP is to agree on new targets for a second commitment period post-2012 as well as associated rules for accounting emissions. Second, the Ad Hoc Working Group on Long-term Cooperative Action under the Convention (AWG-LCA) has also been negotiating commitments for Annex I countries, intending to cover those that have not ratified the Protocol - that is, the USA. In addition, the LCA negotiates "Nationally appropriate mitigation actions" of developing countries, which are to be supported by Annex I countries with technology, financing and capacity-building. Both the actions and the support are to be "measurable, reportable and verifiable". The LCA also negotiates how such support for developing countries' mitigation actions may be delivered as well as how developing countries may be supported in adapting to the impacts of climate change

Sands are running out for climate protection : the Doha Climate Conference once again saves the UN climate process while real climate action is shelved for later

This report analyses the international climate negotiations at the UN climate conference in Doha in December 2012. The report is structured along the three main tracks of the negotiations: the agreement on a second commitment period under the Kyoto Protocol, the closure of the Ad-hoc Working Group on Long-Term Cooperative Action under the Convention, and the start of negotiations on a new comprehensive climate agreement that are to be concluded by 2015

Hepatocyte-Targeted Expression by Integrase-Defective Lentiviral Vectors Induces Antigen-Specific Tolerance in Mice with Low Genotoxic Risk

Lentiviral vectors are attractive tools for liver-directed gene therapy because of their capacity for stable gene expression and the lack of preexisting immunity in most human subjects. However, the use of integrating vectors may raise some concerns about the potential risk of insertional mutagenesis. Here we investigated liver gene transfer by integrase-defective lentiviral vectors (IDLVs) containing an inactivating mutation in the integrase (D64V). Hepatocyte-targeted expression using IDLVs resulted in the sustained and robust induction of immune tolerance to both intracellular and secreted proteins, despite the reduced transgene expression levels in comparison with their integrase-competent vector counterparts. IDLV-mediated and hepatocyte-targeted coagulation factor IX (FIX) expression prevented the induction of neutralizing antibodies to FIX even after antigen rechallenge in hemophilia B mice and accounted for relatively prolonged therapeutic FIX expression levels. Upon the delivery of intracellular model antigens, hepatocyte-targeted IDLVs induced transgene-specific regulatory T cells that contributed to the observed immune tolerance. Deep sequencing of IDLV-transduced livers showed only rare genomic integrations that had no preference for gene coding regions and occurred mostly by a mechanism inconsistent with residual integrase activity. Conclusion: IDLVs provide an attractive platform for the tolerogenic expression of intracellular or secreted proteins in the liver with a substantially reduced risk of insertional mutagenesis. (hepatology 2011;

Leave no stone unturned: individually adapted xerotolerant Thaumarchaeota sheltered below the boulders of the Atacama Desert hyperarid core

Background: The hyperarid core of the Atacama Desert is an extremely harsh environment thought to be colonized by only a few heterotrophic bacterial species. Current concepts for understanding this extreme ecosystem are mainly based on the diversity of these few species, yet a substantial area of the Atacama Desert hyperarid topsoil is covered by expansive boulder accumulations, whose underlying microbiomes have not been investigated so far. With the hypothesis that these sheltered soils harbor uniquely adapted microbiomes, we compared metagenomes and geochemistry between soils below and beside boulders across three distantly located boulder accumulations in the Atacama Desert hyperarid core. Results: Genome-resolved metagenomics of eleven samples revealed substantially different microbial communities in soils below and beside boulders, despite the presence of shared species. Archaea were found in significantly higher relative abundance below the boulders across all samples within distances of up to 205 km. These key taxa belong to a novel genus of ammonia-oxidizing Thaumarchaeota, Candidatus Nitrosodeserticola. We resolved eight mid-to-high quality genomes of this genus and used comparative genomics to analyze its pangenome and site-specific adaptations. Ca. Nitrosodeserticola genomes contain genes for ammonia oxidation, the 3-hydroxypropionate/4-hydroxybutyrate carbon fixation pathway, and acetate utilization indicating a chemolithoautotrophic and mixotrophic lifestyle. They also possess the capacity for tolerating extreme environmental conditions as highlighted by the presence of genes against oxidative stress and DNA damage. Site-specific adaptations of the genomes included the presence of additional genes for heavy metal transporters, multiple types of ATP synthases, and divergent genes for aquaporins. Conclusion: We provide the first genomic characterization of hyperarid soil microbiomes below the boulders in the Atacama Desert, and report abundant and highly adapted Thaumarchaeaota with ammonia oxidation and carbon fixation potential. Ca. Nitrosodeserticola genomes provide the first metabolic and physiological insight into a thaumarchaeal lineage found in globally distributed terrestrial habitats characterized by various environmental stresses. We consequently expand not only the known genetic repertoire of Thaumarchaeota but also the diversity and microbiome functioning in hyperarid ecosystems. Conclusion: We provide the first genomic characterization of hyperarid soil microbiomes below the boulders in the Atacama Desert, and report abundant and highly adapted Thaumarchaeaota with ammonia oxidation and carbon fixation potential. Ca. Nitrosodeserticola genomes provide the first metabolic and physiological insight into a thaumarchaeal lineage found in globally distributed terrestrial habitats characterized by various environmental stresses. We consequently expand not only the known genetic repertoire of Thaumarchaeota but also the diversity and microbiome functioning in hyperarid ecosystems.EC/FP7/339231/EU/Habitability of Martian Environments: Exploring the Physiological and Environmental Limits of Life/HOM

The clean development mechanism : a tool for financing low carbon development in Africa?

Purpose - Since the registration of the first clean development mechanism (CDM) project in 2004, the CDM has seen a dynamic expansion: the CDM pipeline currently comprises 6,725 projects generating 2.73 billion certified emission reductions (CERs) up to 2012. These CERs result in a substantial financial flow from Annex I to Non-Annex I countries. But CDM projects also result in investments in low carbon technologies, a substantial share of which is focused on the energy sector. The total installed capacity of all CDM projects amounts to 288,944 MW. However, the CDM is not widely taken up in Africa. This holds true for Africa's share in the CDM project pipeline (2.62 per cent), for Africa's share in CERs generated up to 2012 (3.58 per cent) and for the normalized CERs per capita, per country. Two hypothesizes are commonly discussed: first, the continent features low per capita emissions and low abatement potentials. Second, African countries may be hampered by weak institutional frameworks. This article reviews both hypotheses and presents new empirical data. The paper aims to discuss these issues. Design/methodology/approach - Investigating the greenhouse gas (GHS) abatement potential of 16 energy-related sectors for 11 selected least developed countries in sub-Saharan Africa shows a total theoretical CDM potential of 128.6 million CERs per year. Analyzing investment indicators confirms that most countries are impeded by below average investment conditions. Findings - It is concluded that Africa offers a considerable range of substantial abatement potentials. However, the weak institutional framework is limiting the uptake of the CDM in Africa. This is underpinned by an analysis which shows if a CDM sector has high investment cost, Africa will have a low share in the sector. If the sector has low investment needs per CER, Africa's share in the CDM sector will be bigger. Investment needs and Africa's share in the pipeline feature a negative correlation. Research limitations/implications - Supporting CDM development in Africa should not be constraint to technical assistance. It will be crucial to develop an integrated financing approach, comprising the CDM as a co-financing mechanism, to overcome the institutional challenges. Originality/value - Until today, there are few empirical studies that use concrete criteria and indicators to show why the CDM is underrepresented in Africa. The work presented here contributes to filling this gap

Positive results, no negative consequences : no-harm options for article 6

The objective of this paper is to analyse and make recommendations on a safeguard system for Article 6 that aims at preventing potential harm that mitigation activities may cause on the ground to local stakeholders and the environment. Following some definitory aspects of what and how to safeguard, the paper analyses a number of safeguard systems and do no harm principles as well as tools to implement them. It then gives an overview on Parties' views on the matter, as uttered in their latest submissions on Art. 6 options, as well as an overview of the references in the UNFCCC's SBSTA Chair's text with respect to sustainable development, safeguards, and human rights issues. The paper closes with recommendations on a possible safeguard system for Article 6