Homochirality in an early peptide world

A recently proposed model of non-autocatalytic reactions in dipeptide reactions leading to spontaneous symmetry breaking and homochirality is examined. The model is governed by activation, polymerization, epimerization and depolymerization of amino acids. Symmetry breaking is primarily a consequence of the fact that the rates of reactions involving homodimers and heterodimers are different, i.e., stereoselective, and on the fact that epimerization can only occur on the N-terminal residue and not on the Cterminal residue. This corresponds to an auto-inductive cyclic process that works only in one sense. It is argued that epimerization mimics both autocatalytic behavior as well as mutual antagonism - both of which were known to be crucial for producing full homochirality.Comment: 19 pages, 7 figures, 3 boxe

Consolidations and the Sequence of Acquisitions to Monopoly

We examine horizontal merger activity between firms which have differing costs. Upon merging owners can transfer technology to an acquired firm and can decide whether to operate their firms as separate entities in the product market or consolidate their acquisitions. Thus, in our analysis, mergers can exhibit both an efficiency effect and a market power effect. The purchase prices of target firms are determined via a bargaining game. We find that the largest firm is likely to be acquisitive and that the optimal sequence of mergers entails targeting the next largest rival firm. We find that not consolidating an acquired firm can reveal the intention to acquire additional firms. The optimal sequence of mergers with technology transfers and no consolidations is found initially to be welfare improving. Ultimately, however, the acquisitions lead to consolidation and a decrease in total welfare. ZUSAMMENFASSUNG - (Konsolidierungen und die Folge von Akquisitionen zum Monopol) In dem Beitrag werden horizontale Unternehmenszusammenschlüsse zwischen Unternehmen mit unterschiedlichen Kosten analysiert. Für das erwerbende Unternehmen stellt sich die Frage, ob es Technologie zu einer erworbenen Firma transferieren sollte und, ob es das erworbene Unternehmen als getrennte Einheit im Produktmarkt betreiben oder mit dem fusionierten Unternehmen zusammen am Markt operieren will. In der Analyse wird der Effizienzeffekt und der Marktmachteffekt berücksichtigt. Der Kaufpreis des zu erwerbenden Unternehmens wird in einem "bargaining game" ermittelt. Im Ergebnis zeigt sich, daß das größte Unternehmen wahrscheinlich das erwerbende sein wird und daß die optimale Reihenfolge von Fusionen sich auf das nächst größte Konkurrenzunternehmen bezieht. Außerdem zeigt sich, daß die Nichtkonsolidierung mit erworbenen Unternehmen daraufhin deutet, daß eine Intention zum Erwerb weiterer Firmen vorliegt. Die optimale Folge von Fusionen mit Technologietransfer und ohne Konsolidierungen erhöht anfangs die Wohlfahrt. Letztlich aber führen die Erwerbungen zur Konsolidierung und zu einem Absinken der Gesamtwohlfahrt.

Suzaku observations of X-ray excess emission in the cluster of galaxies A3112

We analysed the Suzaku XIS1 data of the A3112 cluster of galaxies in order to examine the X-ray excess emission in this cluster reported earlier with the XMM-Newton and Chandra satellites. The best-fit temperature of the intracluster gas depends strongly on the choice of the energy band used for the spectral analysis. This proves the existence of excess emission component in addition to the single-temperature MEKAL in A3112. We showed that this effect is not an artifact due to uncertainties of the background modeling, instrument calibration or the amount of Galactic absorption. Neither does the PSF scatter of the emission from the cool core nor the projection of the cool gas in the cluster outskirts produce the effect. Finally we modeled the excess emission either by using an additional MEKAL or powerlaw component. Due to the small differencies between thermal and non-thermal model we can not rule out the non-thermal origin of the excess emission based on the goodness of the fit. Assuming that it has a thermal origin, we further examined the Differential Emission Measure (DEM) models. We utilised two different DEM models, a Gaussian differential emission measure distribution (GDEM) and WDEM model, where the emission measure of a number of thermal components is distributed as a truncated power law. The best-fit XIS1 MEKAL temperature for the 0.4-7.0 keV band is 4.7+-0.1 keV, consistent with that obtained using GDEM and WDEM models.Comment: 8 pages, 10 figures, accepted to A&

Biogas from manure – a new technology to close the nutrient and energy circuit on-farm

The Biodynamic Research Institute in Järna developed a two-phase on-farm biogas plant. The plant digests manure of dairy cattle and organic residues originating from the farm and the surrounding food processing units containing 17.7-19.6 % total solids. A new technology for continuously filling and discharging the hydrolysis reactor was developed and implemented. The output of the hydrolysis reactor is separated into a solid and liquid fraction. The solid fraction is composted. The liquid fraction is further digested in a methane reactor and the effluent used as liquid fertiliser. Initial results show that anaerobic digestion followed by aerobic composting of the solid fraction improves the nutrient balance of the farm compared to mere aerobic composting. Composted solid fraction and effluent together contain about 70.8 % of total input nitrogen and 93.3 % of input NH4. The manure that was merely aerobic digested contained about 51.3 % of total input nitrogen and 3.9 % of input NH4. Additionally anaerobic digestion improves the energy balance of the farm producing up to 269 l biogas kg-1 volatile solids or 1.7 kWh heat kg-1 volatile solids

Stuck between Bench and Bedside : Why Non-invasive Brain Stimulation Is Not Accessible to Depressed Patients in Europe

Peer reviewe

UBVRI photopolarimetry of the long period eclipsing AM Herculis binary V1309

We report simultaneous UBVRI photo-polarimetric observations of the long period (7.98 h) AM Her binary V1309 Ori. The length and shape of the eclipse ingress and egress varies from night to night. We suggest this is due to the variation in the brightness of the accretion stream. By comparing the phases of circular polarization zero-crossovers with previous observations, we confirm that V1309 Ori is well synchronized, and find an upper limit of 0.002 percent for the difference between the spin and orbital periods. We model the polarimetry data using a model consisting of two cyclotron emission regions at almost diametrically opposite locations, and centered at colatitude 35 (deg) and 145 (deg) on the surface of the white dwarf. We also present archive X-ray observations which show that the negatively polarised accretion region is X-ray bright.Comment: 11 pages, 12 figures (2 colour), Fig1 and Fig 4 are in lower resolution than in original paper, accepted for publication in Monthly Notices of the Royal Astronomical Societ

Delayed, distant skin lesions after transcranial direct current stimulation

Non peer reviewe