Coexistence of qubit effects

Two quantum events, represented by positive operators (effects), are coexistent if they can occur as possible outcomes in a single measurement scheme. Equivalently, the corresponding effects are coexistent if and only if they are contained in the ranges of a single (joint) observable. Here we give several equivalent characterizations of coexistent pairs of qubit effects. We also establish the equivalence between our results and those obtained independently by other authors. Our approach makes explicit use of the Minkowski space geometry inherent in the four-dimensional real vector space of selfadjoint operators in a two-dimensional complex Hilbert space

Ultrafast spin dynamics: complementing theoretical analyses by quantum-information measures

Theoretical analyses of ultrafast spin dynamics commonly address and discuss simulated phenomena by means of observables, whereas in quantum information theory one often utilizes measures of quantum states. In this Paper we report on possible benefits of quantum information measures in simulations of ultrafast spin dynamics. For Co/Cu heterostructures illuminated by femtosecond laser pulses, we discuss the general behaviour of quantum information measures, in particular distances in Hilbert space and degrees of mixing in the density matrix. The measures are in particular sensitive to variations of the polarization of a laser pulse and the sample composition. Moreover, they are closely related to magnetization and number of excited electrons

Ultrafast Dynamics of Orbital Angular Momentum of Electrons Induced by Femtosecond Laser Pulses: Generation and Transfer Across Interfaces

The orbital angular momenta (OAM) of electrons play an increasingly important role in ultrafast electron and magnetization dynamics. In this theoretical study, we investigate the electron dynamics induced by femtosecond laser pulses in a normal metal, a ferromagnet, and a ferromagnet/normal metal heterostructure. We analyze the spatio-temporal distributions of the laser-induced OAM and their respective currents. Our findings demonstrate that a circularly polarized laser pulse can induce a sizable and long-lasting OAM component in a normal metal. Furthermore, an interface between a ferromagnet and a normal metal facilitates the demagnetization of the magnet by the OAM contribution to the total magnetization. Finally, to transfer OAM from a ferromagnet into a normal metal, it is advantageous to use a laser setup that induces the desired OAM component in the ferromagnet, but not in the normal metal

Respiratory chain complexes in dynamic mitochondria display a patchy distribution in life cells

Background: Mitochondria, the main suppliers of cellular energy, are dynamic organelles that fuse and divide frequently. Constraining these processes impairs mitochondrial is closely linked to certain neurodegenerative diseases. It is proposed that functional mitochondrial dynamics allows the exchange of compounds thereby providing a rescue mechanism. Methodology/Principal Findings: The question discussed in this paper is whether fusion and fission of mitochondria in different cell lines result in re-localization of respiratory chain (RC) complexes and of the ATP synthase. This was addressed by fusing cells containing mitochondria with respiratory complexes labelled with different fluorescent proteins and resolving their time dependent re-localization in living cells. We found a complete reshuffling of RC complexes throughout the entire chondriome in single HeLa cells within 2–3 h by organelle fusion and fission. Polykaryons of fused cells completely re-mixed their RC complexes in 10–24 h in a progressive way. In contrast to the recently described homogeneous mixing of matrix-targeted proteins or outer membrane proteins, the distribution of RC complexes and ATP synthase in fused hybrid mitochondria, however, was not homogeneous but patterned. Thus, complete equilibration of respiratory chain complexes as integral inner mitochondrial membrane complexes is a slow process compared with matrix proteins probably limited by complete fusion. In co-expressing cells, complex II is more homogenously distributed than complex I and V, resp. Indeed, this result argues for higher mobility and less integration in supercomplexes. Conclusion/Significance: Our results clearly demonstrate that mitochondrial fusion and fission dynamics favours the re-mixing of all RC complexes within the chondriome. This permanent mixing avoids a static situation with a fixed composition of RC complexes per mitochondrion

Accurate and Automated High-Coverage Identification of Chemically Cross-Linked Peptides with MaxLynx

Cross-linking combined with mass spectrometry (XL-MS) provides a wealth of information about the three-dimensional (3D) structure of proteins and their interactions. We introduce MaxLynx, a novel computational proteomics workflow for XL-MS integrated into the MaxQuant environment. It is applicable to noncleavable and MS-cleavable cross-linkers. For both, we have generalized the Andromeda peptide database search engine to efficiently identify cross-linked peptides. For noncleavable peptides, we implemented a novel dipeptide Andromeda score, which is the basis for a computationally efficient N-squared search engine. Additionally, partial scores summarize the evidence for the two constituents of the dipeptide individually. A posterior error probability (PEP) based on total and partial scores is used to control false discovery rates (FDRs). For MS-cleavable cross-linkers, a score of signature peaks is combined with the conventional Andromeda score on the cleavage products. The MaxQuant 3D peak detection was improved to ensure more accurate determination of the monoisotopic peak of isotope patterns for heavy molecules, which cross-linked peptides typically are. A wide selection of filtering parameters can replace the manual filtering of identifications, which is often necessary when using other pipelines. On benchmark data sets of synthetic peptides, MaxLynx outperforms all other tested software on data for both types of cross-linkers and on a proteome-wide data set of cross-linked Drosophila melanogaster cell lysate. The workflow also supports ion mobility-enhanced MS data. MaxLynx runs on Windows and Linux, contains an interactive viewer for displaying annotated cross-linked spectra, and is freely available at https://www.maxquant.org/.publishedVersio

Gouvernance de la zone Euro : comment prévenir la défaillance du politique ? – Le point de vue allemand –

Dix ans après sa création, l’Union monétaire traverse une profonde crise, au point même de nourrir, à la fin 2011, la crainte d’un éclatement de la zone Euro. La principale raison évoquée est que, si ses pères fondateurs avaient pu unifier la politique monétaire, ils n’ont pas réussi à sceller une Union politique et encore moins à faire en sorte que les politiques fiscale, budgétaire et économique menées par chacun des membres de la zone Euro respectent suffisamment les engagements liés à la monnaie unique. Malgré l’impossibilité de sceller jusqu’ici une Union politique, l’Union économique et monétaire (UEM) n’est pas pour autant condamnée à l’échec ; la centralisation de ces politiques n’est en effet pas le préalable au succès durable de l’Euro. Car les enseignements tirés de la crise de la dette au sein de la zone Euro – et bien plus encore les réformes qu’elle a suscitées – ont considérablement amélioré les conditions grâce auxquelles une action autonome, non centralisée, des Etats membres suffira pour préserver l’avenir de l’Euro. A l’appui de cette thèse, nous passerons en revue les multiples réformes engagées récemment, souvent d’ailleurs à l’initiative de l’Allemagne. Leur adoption n‘a pas été chose aisée et s’était heurtée parfois à la forte résistance des Etats du sud de la zone Euro, et en partie de la France. Elles s’expliquent par de profondes divergences dans l’approche de la politique économique, de la notion de l’Etat et de son rôle, comme des mécanismes du marché, qui distinguent la France et l’Allemagne et sont particulièrement flagrantes depuis l’alternance politique à la suite des élections présidentielles de mai 2012. L’approche allemande, que cette contribution cherche à rendre plus accessible au lecteur français, repose sur le concept, largement partagé par la coalition actuellement au gouvernement (et même au-delà), de l‘Ordnungspolitik. Ce terme, qui n’a pas d’équivalent en français, désigne le fait que le rôle de l’Etat est de fixer un ensemble de règles (« ordre ») permettant aux forces du marché de fonctionner efficacement. Dans l‘approche ordo-libérale, le défi consiste donc à prévenir la défaillance du marché. Aujourd’hui, ce défi s’étend également à la prévention du risque de défaillance de l’Etat, ce qui amène à considérer sous l’angle des incitations économiques jusqu’à l’action des acteurs politiques eux-mêmes

Effects of 1,25(OH)2D3 on compensatory renal growth in the growing rat

Effects of 1,25(OH)2D3 on compensatory renal growth in the growing rat. Renal compensatory growth after uninephrectomy (UNX) was examined in vitamin D replete male 100g Sprague-Dawley rats. Five days after UNX, the contralateral kidney wet weight increased by 25% with the kidney weight/body weight ratio reaching a plateau by day 7 after UNX. The early weight increase was primarily due to an increased cell number, as evaluated by a stereological technique in perfusion-fixed kidneys. Twenty pmol 1,25(OH)2D3 by daily s.c. injection increased time-averaged 1,25(OH)2D3 concentrations 3.3-fold and reduced the increment in the kidney weight of UNX pairfed rats compared to solvent UNX controls. The number of mitoses (whole kidney and different nephron segments) were significantly reduced by giving 1,25(OH)2D3 to UNX animals at different levels of food intake. The effect was also demonstrable in PTX animals on a constant infusion of exogenous PTH (100 ng/kg/hr 1,34 bPTH by osmotic minipump). The data suggest that changes of 1,25(OH)2D3 concentration within a physiologically relevant range modulate compensatory (and possibly basal) growth of the kidney