Life cycle-based environmental impacts of energy system transformation strategies for Germany: Are climate and environmental protection conflicting goals?

In the development of climate-friendly energy system transformation strategies it is often ignored that environmental protection encompasses more than climate protection alone. There is therefore a risk of developing transformation strategies whose climate friendliness comes at the expense of higher other environmental impacts. Consequently, an assessment of environmental impacts of energy system transformation strategies is required if undesired environmental side effects of the energy system transformation are to be avoided and transformation strategies are to be developed that are both climate and environmentally friendly. In this paper, ten structurally different transformation strategies for the German energy system were re-modeled (in a harmonized manner). Five of these scenarios describe pathways for a reduction of direct, energy related CO$_2$ emissions by 80%, the other five by 95%. Life cycle-based environmental impacts of the scenarios were assessed by coupling the scenario results with data from a life cycle inventory database focusing on energy and transport technologies. The results show that the transformation to a climate-friendly energy system reduces environmental impacts in many impact categories. However, exceptions occur with respect to the consumption of mineral resources, land use and certain human health indicators, which could increase with decreasing CO$_2$ emissions. The comparison of environmental impacts of moderately ambitious strategies (80% CO$_2$ reduction) with very ambitious strategies (95% CO$_2$ reduction) shows that there is a risk of increasing environmental impacts with increasing climate protection, although very ambitious strategies do not necessarily come along with higher environmental impacts than moderately ambitious strategies. A reduction of environmental impacts could be achieved by a moderate and – as far as possible – direct electrification of heat and transport, a balanced technology mix for electricity generation, by reducing the number and size of passenger cars and by reducing the environmental impacts from the construction of these vehicles

Integrated multidimensional sustainability assessment of energy system transformation pathways

Sustainable development embraces a broad spectrum of social, economic and ecological aspects. Thus, a sustainable transformation process of energy systems is inevitably multidimensional and needs to go beyond climate impact and cost considerations. An approach for an integrated and interdisciplinary sustainability assessment of energy system transformation pathways is presented here. It first integrates energy system modeling with a multidimensional impact assessment that focuses on life cycle-based environmental and macroeconomic impacts. Then, stakeholders’ preferences with respect to defined sustainability indicators are inquired, which are finally integrated into a comparative scenario evaluation through a multi-criteria decision analysis (MCDA), all in one consistent assessment framework. As an illustrative example, this holistic approach is applied to the sustainability assessment of ten different transformation strategies for Germany. Applying multi-criteria decision analysis reveals that both ambitious (80%) and highly ambitious (95%) carbon reduction scenarios can achieve top sustainability ranks, depending on the underlying energy transformation pathways and respective scores in other sustainability dimensions. Furthermore, this research highlights an increasingly dominant contribution of energy systems’ upstream chains on total environmental impacts, reveals rather small differences in macroeconomic effects between different scenarios and identifies the transition among societal segments and climate impact minimization as the most important stakeholder preferences

Seeing like the international community: how peacebuilding failed (and survived) in Tajikistan

Post-print version. 18 month embargo by the publisher. Article will be released April 2010.The international community claims transformative power over post-conflict spaces via the concept of peacebuilding. International actors discursively make space for themselves in settings such as the Central Asian state of Tajikistan which endured a civil war during the 1990s and has only seen an end to widespread political violence in recent years. With the work of James C. Scott, this paper challenges the notion that post-conflict spaces are merely the objects of international intervention. It reveals how, even in cases of apparent stability such as that of Tajikistan, international actors fail to achieve their ostensible goals for that place yet make space for themselves in that place. International peacebuilders may provide essential resources for the re-emergence of local forms of order yet these symbolic and material resources are inevitably re-interpreted and re-appropriated by local actors to serve purposes which may be the opposite of their aims. However, despite this ‘failure’ of peacebuilding it nevertheless survives as a discursive construction through highly subjective processes of monitoring and evaluation. So maintained, peacebuilding is a constitutive element of world order where the necessity of intervention for humanitarian, democratic and statebuilding ends goes unchallenged. This raises the question of what or where – in spatial terms – is the locus of international intervention: the local recipients of peacebuilding programmes (who are the ostensible targets) or ‘the International Community’ itself (whose space is re-inscribed as that of an imperfect but necessary regulator of world order)

Beyond BMI for self-estimates of body size and shape: A new method for developing stimuli correctly calibrated for body composition

Accurate self-assessment of body shape and size plays a key role in the prevention, diagnosis, and treatment of both obesity and eating disorders. These chronic conditions cause significant health problems, reduced quality of life, and represent a major problem for health services. Variation in body shape depends on two aspects of composition: adiposity and muscularity. However, most self-assessment tools are unidimensional. They depict variation in adiposity only, typically quantified by the body mass index. This can lead to substantial, and clinically meaningful, errors in estimates of body shape and size. To solve this problem, we detail a method of creating biometrically valid body stimuli. We obtained high-resolution 3D body shape scans and composition measures from 397 volunteers (aged 18–45 years) and produced a statistical mapping between the two. This allowed us to create 3D computer-generated models of bodies, correctly calibrated for body composition (i.e., muscularity and adiposity). We show how these stimuli, whose shape changes are based on change in composition in two dimensions, can be used to match the body size and shape participants believe themselves to have, to the stimulus they see. We also show how multivariate multiple regression can be used to model shape change predicted by these 2D outcomes, so that participants’ choices can be explained by their measured body composition together with other psychometric variables. Together, this approach should substantially improve the accuracy and precision with which self-assessments of body size and shape can be made in obese individuals and those suffering from eating disorders

SecA, a remarkable nanomachine

Biological cells harbor a variety of molecular machines that carry out mechanical work at the nanoscale. One of these nanomachines is the bacterial motor protein SecA which translocates secretory proteins through the protein-conducting membrane channel SecYEG. SecA converts chemically stored energy in the form of ATP into a mechanical force to drive polypeptide transport through SecYEG and across the cytoplasmic membrane. In order to accommodate a translocating polypeptide chain and to release transmembrane segments of membrane proteins into the lipid bilayer, SecYEG needs to open its central channel and the lateral gate. Recent crystal structures provide a detailed insight into the rearrangements required for channel opening. Here, we review our current understanding of the mode of operation of the SecA motor protein in concert with the dynamic SecYEG channel. We conclude with a new model for SecA-mediated protein translocation that unifies previous conflicting data

Topogenesis of membrane proteins at the endoplasmic reticulum

Most eukaryotic membrane proteins are cotranslationally integrated into the endoplasmic reticulum membrane by the Sec61 translocation complex. They are targeted to the translocon by hydrophobic signal sequences, which induce the translocation of either their N- or their C-terminal sequence. Signal sequence orientation is largely determined by charged residues flanking the apolar sequence (the positive-inside rule), folding properties of the N-terminal segment, and the hydrophobicity of the signal. Recent in vivo experiments suggest that N-terminal signals initially insert into the translocon head-on to yield a translocated N-terminus. Driven by a local electrical potential, the signal may invert its orientation and translocate the C-terminal sequence. Increased hydrophobicity slows down inversion by stabilizing the initial bound state. In vitro cross-linking studies indicate that signals rapidly contact lipids upon entering the translocon. Together with the recent crystal structure of the homologous SecYEbeta translocation complex of Methanococcus jannaschii, which did not reveal an obvious hydrophobic binding site for signals within the pore, a model emerges in which the translocon allows the lateral partitioning of hydrophobic segments between the aqueous pore and the lipid membrane. Signals may return into the pore for reorientation until translation is terminated. Subsequent transmembrane segments in multispanning proteins behave similarly and contribute to the overall topology of the protein