Correlation Effects on Transport Through Few-Electrons Systems

We study lateral tunneling through a quantum box including electron-electron interactions in the presence of a magnetic field which breaks single particle degeneracies. The conductance at zero temperature as a function of the Fermi energy in the leads consists of a set of peaks related to changing by one the electron occupancy in the box. We find that the position and heights of the peaks are controlled by many-body effects. We compute the conductance up to 8 electrons for several cases where correlation effects dominate. In the range of intermediate fields spin selection rules quench some peaks. At low and high fields the behavior of the conductance as a function of the number of electrons is very different due to big changes in the many-body ground state wavefunctions.Comment: 9 pages, 2 postscript figures, Latex 3.1

Relationships among tonic and episodic aspects of motivation to eat, gut peptides, and weight before and after bariatric surgery.

yesBackground The interaction between motivation to eat, eating behaviour traits and gut peptides following gastric bypass (GBP) surgery are not fully understood. Setting Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden. Method Appetite and hormone responses to a fixed liquid pre-load were assessed in 12 obese (BMI 45 ± 1.9 kg/m2) participants immediately before, 3 days, 2 months, and 1 year following gastric by-pass (GBP) surgery. Subjective appetite and plasma levels of ghrelin, leptin, insulin and GLP-1 were measured for a 3-hour postprandial period. Eating behaviour traits were also measured using the TFEQR18. Results There was a decrease in TFEQ Emotional Eating (EE) and Uncontrolled Eating (UE) from pre to 1-year post-surgery, but no significant change in Restraint. In addition, there was a reduction in subjective appetite ratings, and alterations in appetite peptides favouring an anorectic response. Pre-surgery EE was significantly related to fasting and AUC ghrelin; UE was associated with AUC desire to eat while there was a significant association between fasting desire to eat and ghrelin (fasting and AUC). 1 year post-surgery, UE was positively related to fasting insulin and Restraint was negatively associated with GLP-1. UE and subjective hunger were positively correlated, while the relationship between desire to eat and ghrelin remained. Conclusion The relationships amongst subjective appetite ratings, eating behaviour traits and appetite peptides in obese patients both before and at one-year post GBP surgery contribute to the reduction in a propensity to over-eat and weight loss

Expressions of climate perturbations in western Ugandan crater lake sediment records during the last 1000 yr

Equatorial East Africa has a complex, regional patchwork of climate regimes, with multiple interacting drivers. Recent studies have focussed on large lakes and reveal signals that are smoothed in both space and time, and, whilst useful at a continental scale, are of less relevance when understanding short-term, abrupt or immediate impacts of climate and environmental changes. Smaller-scale studies have highlighted spatial complexity and regional heterogeneity of tropical palaeoenvironments in terms of responses to climatic forcing (e.g. the Little Ice Age [LIA]) and questions remain over the spatial extent and synchroneity of climatic changes seen in East African records. Sediment cores from paired crater lakes in western Uganda were examined to assess ecosystem response to long-term climate and environmental change as well as testing responses to multiple drivers using redundancy analysis. These archives provide annual to sub-decadal records of environmental change. The records from the two lakes demonstrate an individualistic response to external (e.g. climatic) drivers, however, some of the broader patterns observed across East Africa suggest that the lakes are indeed sensitive to climatic perturbations such as a dry Mediaeval Climate Anomaly (MCA; 1000–1200 AD) and a relatively drier climate during the main phase of the LIA (1500–1800 AD); though lake levels in western Uganda do fluctuate. The relationship of Ugandan lakes to regional climate drivers breaks down c. 1800 AD, when major changes in the ecosystems appear to be a response to sediment and nutrient influxes as a result of increasing cultural impacts within the lake catchments. The data highlight the complexity of individual lake response to climate forcing, indicating shifting drivers through time. This research also highlights the importance of using multi-lake studies within a landscape to allow for rigorous testing of climate reconstructions, forcing and ecosystem response

HSV-1 Targets Lymphatic Vessels in the Eye and Draining Lymph Node of Mice Leading to Edema in the Absence of a Functional Type I Interferon Response

Herpes simplex virus type-1 (HSV-1) induces new lymphatic vessel growth (lymphangiogenesis) in the cornea via expression of vascular endothelial growth factor by virally infected epithelial cells. Here, we extend this observation to demonstrate the selective targeting of corneal lymphatics by HSV-1 in the absence of functional type I interferon (IFN) pathway. Specifically, we examined the impact of HSV-1 replication on angiogenesis using type I IFN receptor deficient (CD118−/−) mice. HSV-1-induced lymphatic and blood vessel growth into the cornea proper was time-dependent in immunocompetent animals. In contrast, there was an initial robust growth of lymphatic vessels into the cornea of HSV-1-infected CD118−/−mice, but such vessels disappeared by day 5 postinfection. The loss was selective as blood vessel integrity remained intact. Magnetic resonance imaging and confocal microscopy analysis of the draining lymph nodes of CD118−/− mice revealed extensive edema and loss of lymphatics compared with wild-type mice. In addition to a loss of lymphatic vessels in CD118−/− mice, HSV-1 infection resulted in epithelial thinning associated with geographic lesions and edema within the cornea, which is consistent with a loss of lymphatic vasculature. These results underscore the key role functional type I IFN pathway plays in the maintenance of structural integrity within the cornea in addition to the anti-viral characteristics often ascribed to the type I IFN cytokine family

Expressions of climate perturbations in western ugandan crater lake sediment records during the last 1000 years

Equatorial East Africa has a complex regional patchwork of climate regimes, sensitive to climate fluctuations over a variety of temporal and spatial scales during the late Holocene. Understanding how these changes are recorded in and interpreted from biological and geochemical proxies in lake sedimentary records remains a key challenge to answering fundamental questions regarding the nature, spatial extent and synchroneity of climatic changes seen in East African palaeo-records. Using a paired lake approach, where neighbouring lakes share the same geology, climate and landscape, it might be expected that the systems will respond similarly to external climate forcing. Sediment cores from two crater lakes in western Uganda spanning the last ∼1000 years were examined to assess diatom community responses to late Holocene climate and environmental changes, and to test responses to multiple drivers using redundancy analysis (RDA). These archives provide annual to sub-decadal records of environmental chang

Supersymmetric Field-Theoretic Models on a Supermanifold

We propose the extension of some structural aspects that have successfully been applied in the development of the theory of quantum fields propagating on a general spacetime manifold so as to include superfield models on a supermanifold. We only deal with the limited class of supermanifolds which admit the existence of a smooth body manifold structure. Our considerations are based on the Catenacci-Reina-Teofillatto-Bryant approach to supermanifolds. In particular, we show that the class of supermanifolds constructed by Bonora-Pasti-Tonin satisfies the criterions which guarantee that a supermanifold admits a Hausdorff body manifold. This construction is the closest to the physicist's intuitive view of superspace as a manifold with some anticommuting coordinates, where the odd sector is topologically trivial. The paper also contains a new construction of superdistributions and useful results on the wavefront set of such objects. Moreover, a generalization of the spectral condition is formulated using the notion of the wavefront set of superdistributions, which is equivalent to the requirement that all of the component fields satisfy, on the body manifold, a microlocal spectral condition proposed by Brunetti-Fredenhagen-K\"ohler.Comment: Final version to appear in J.Math.Phy

Evidence for a bi-partition of the Younger Dryas Stadial in East Asia associated with inversed climate characteristics compared to Europe

The Younger Dryas Stadial (YDS) was an episode of northern hemispheric cooling which occurred within the Last Glacial Interglacial Transition (LGIT). A major driver for the YDS climate was a weakening of the Atlantic Meridional Overturning Circulation (AMOC). It has been inferred that the AMOC began to strengthen mid-YDS, producing a bipartite structure of the YDS in records from continental Europe. These records imply that the polar front and westerlies shifted northward, producing a warmer second phase of the YDS in Europe. Here we present multi-proxy data from the sediments of Lake Suigetsu (Japan), as evidence that a related bi-partition of the YDS also occurred in East Asia. Besides showing for the first time that the bi-partition was not limited to the North Atlantic/European region, the data also imply a climatic dipole between Europe and East Asia since the cold-warm characteristics are reversed at Lake Suigetsu. We suggest that changes in eastward moisture transport from the North Atlantic are the primary mechanism by which the teleconnection can be explained

Spatial updating in narratives.

Across two experiments we investigated spatial updating in environments encoded through narratives. In Experiment 1, in which participants were given visualization instructions to imagine the protagonist’s movement, they formed an initial representation during learning but did not update it during subsequent described movement. In Experiment 2, in which participants were instructed to physically move in space towards the directions of the described objects prior to testing, there was evidence for spatial updating. Overall, findings indicate that physical movement can cause participants to link a spatial representation of a remote environment to a sensorimotor framework and update the locations of remote objects while they move

Numerical semigroups with large embedding dimension satisfy Wilf's conjecture

We give an affirmative answer to Wilf's conjecture for numerical semigroups satisfying 2 \nu \geq m, where \nu and m are respectively the embedding dimension and the multiplicity of a semigroup. The conjecture is also proved when m \leq 8 and when the semigroup is generated by a generalized arithmetic sequence.Comment: 13 page

On manifolds with nonhomogeneous factors

We present simple examples of finite-dimensional connected homogeneous spaces (they are actually topological manifolds) with nonhomogeneous and nonrigid factors. In particular, we give an elementary solution of an old problem in general topology concerning homogeneous spaces