Reversibility of Arctic Sea Ice Retreat - A Multi-Scale Modeling Approach

Arctic summer sea ice has been retreating rapidly over past decade. Climate model projections show further retreat under typical forcing scenarios. The mode of the retreat is a matter of debate. Low-order models show reversible and irreversible retreat depending on the shape of the albedo parametrization. Climate models do not show irreversible sea ice losses, but generally underestimate the current trend of retreat

To what extent does productivity drive the dollar?

The continuing strength of the dollar has fueled interest in the relationship between productivity and exchange rates. An analysis of the link between the dollar's movements and productivity developments in the United States, Japan, and the euro area suggests that productivity can account for much of the change in the external value of the dollar over the past three decades.Foreign exchange rates ; Labor productivity ; Dollar, American

Laboratory rotational ground state transitions of NH3_3D+^+ and CF+^+

Aims. This paper reports accurate laboratory frequencies of the rotational ground state transitions of two astronomically relevant molecular ions, NH3D+ and CF+. Methods. Spectra in the millimeter-wave band were recorded by the method of rotational state-selective attachment of He-atoms to the molecular ions stored and cooled in a cryogenic ion trap held at 4 K. The lowest rotational transition in the A state (ortho state) of NH$_3$D$^+$ ($J_K = 1_0 - 0_0$), and the two hyperfine components of the ground state transition of CF$^+$($J = 1 - 0$) were measured with a relative precision better than $10^{-7}$. Results. For both target ions the experimental transition frequencies agree with recent observations of the same lines in different astronomical environments. In the case of NH$_3$D$^+$ the high-accuracy laboratory measurements lend support to its tentative identification in the interstellar medium. For CF$^+$ the experimentally determined hyperfine splitting confirms previous quantum-chemical calculations and the intrinsic spectroscopic nature of a double-peaked line profile observed in the $J = 1 - 0$ transition towards the Horsehead PDR.Comment: 7 pages, 2 figure

Globalization, markups and the natural rate of interest

In this paper, we investigate how, in a stylised theoretical framework, an increase in the degree of globalization - modelled as a deline in trade costs - affects the real natural rate of interest by impacting firms markups. Outlining a two- country dynamic general equilibrium model with endogenous elasticity of substitution between goods, we suggest two main propositions: 1) Globalization - via the impplied variation in markups - has a potentially significant impact on the natural rate of interest. 2) Simple, plausible markup dynamics may have contributed to explain the recent "conundrum" of world interest rates.globalization, natural interest rate, trade costs

EcoDesign for Production Plants

AbstractDue to rising energy prices and stricter regulations of carbon dioxide emissions, it is not sufficient to optimize energy consumption only during the utilization of products; production has to become more energy efficient, too. In order to reduce the energy demand, energy concerning aspects must be considered early in the development process of the production plants. In these phases, attributes that are responsible for the later energy consumption are predetermined. But the energy demand is often not in focus of the development process. For that reason a methodology for the development of energy efficient production plants is currently being developed by the authors

The generation of resonant turbulence for a premixed burner

Is it possible to optimize the turbulent combustion of a low swirl burner by using resonance in turbulence? To that end an active grid is constructed that consists of two perforated disks of which one is rotating, creating a system of pulsating jets, which in the end can be used as a central blocking grid of a low swirl burner. The turbulence originating from this grid is studied by hot wire anemometry to see if there is a frequency for maximal response. Although no resonant enhancement of the turbulent kinetic energy or the dissipation rate is observed, the results for the two different sets of disks show that significant turbulent fluctuations are introduced mainly in the energy containing range and partially in the inertial sub range. These fluctuations represent up to 25% of the total turbulent energy and are not caused by pulsations of the mean flow

Synthesis of bacteriophage lytic proteins against Streptococcus pneumoniae in the chloroplast of Chlamydomonas reinhardtii.

There is a pressing need to develop novel antibacterial agents given the widespread antibiotic resistance among pathogenic bacteria and the low specificity of the drugs available. Endolysins are antibacterial proteins that are produced by bacteriophage-infected cells to digest the bacterial cell wall for phage progeny release at the end of the lytic cycle. These highly efficient enzymes show a considerable degree of specificity for the target bacterium of the phage. Furthermore, the emergence of resistance against endolysins appears to be rare as the enzymes have evolved to target molecules in the cell wall that are essential for bacterial viability. Taken together, these factors make recombinant endolysins promising novel antibacterial agents. The chloroplast of the green unicellular alga Chlamydomonas reinhardtii represents an attractive platform for production of therapeutic proteins in general, not least due to the availability of established techniques for foreign gene expression, a lack of endotoxins or potentially infectious agents in the algal host, and low cost of cultivation. The chloroplast is particularly well suited to the production of endolysins as it mimics the native bacterial expression environment of these proteins while being devoid of their cell wall target. In this study the endolysins Cpl-1 and Pal, specific to the major human pathogen Streptococcus pneumoniae, were produced in the C. reinhardtii chloroplast. The antibacterial activity of cell lysates and the isolated endolysins was demonstrated against different serotypes of S. pneumoniae, including clinical isolates and total recombinant protein yield was quantified at ~1.3 mg/g algal dry weight. This article is protected by copyright. All rights reserved