Affine bundles are affine spaces over modules

We show that the category of affine bundles over a smooth manifold M is equivalent to the category of affine spaces modelled on projective finitely generated C^\infty(M)-modules. Using this equivalence of categories, we are able to give an alternate proof of the main result of [13], showing that the characterization of vector bundles by means of their Lie algebras of homogeneous differential operators also holds for vector bundles of rank 1 and over any base manifolds.Comment: 13 page

Natural and Projectively Invariant Quantizations on Supermanifolds

The existence of a natural and projectively invariant quantization in the sense of P. Lecomte [Progr. Theoret. Phys. Suppl. (2001), no. 144, 125-132] was proved by M. Bordemann [math.DG/0208171], using the framework of Thomas-Whitehead connections. We extend the problem to the context of supermanifolds and adapt M. Bordemann's method in order to solve it. The obtained quantization appears as the natural globalization of the $\mathfrak{pgl}({n+1|m})$-equivariant quantization on ${\mathbb{R}}^{n|m}$ constructed by P. Mathonet and F. Radoux in [arXiv:1003.3320]. Our quantization is also a prolongation to arbitrary degree symbols of the projectively invariant quantization constructed by J. George in [arXiv:0909.5419] for symbols of degree two

Quantifications en supergéométrie

Le poster présente de façon vulgarisée certaines idées sous-jacentes à la recherche de quantifications invariantes en supergéométrie

Geodesics on a supermanifold and projective equivalence of super connections

We investigate the concept of projective equivalence of connections in supergeometry. To this aim, we propose a definition for (super) geodesics on a supermanifold in which, as in the classical case, they are the projections of the integral curves of a vector field on the tangent bundle: the geodesic vector field associated with the connection. Our (super) geodesics possess the same properties as the in the classical case: there exists a unique (super) geodesic satisfying a given initial condition and when the connection is metric, our supergeodesics coincide with the trajectories of a free particle with unit mass. Moreover, using our definition, we are able to establish Weyl's characterization of projective equivalence in the super context: two torsion-free (super) connections define the same geodesics (up to reparametrizations) if and only if their difference tensor can be expressed by means of a (smooth, even, super) 1-form.Comment: 20 page

Affine bundles are affine spaces

We show that the category of affine bundles over a smooth manifold M is equivalent to that of affine spaces modeled on locally free modules over the algebra of smooth functions on M

Integrated Circuits Based on 300 GHz fT Metamorphic HEMT Technology for Millimeter-Wave and Mixed-Signal Applications

Advanced circuits based on metamorphic HEMT (MHEMT)technologies on 4 ”GaAs substrates for both millimeter-wave,and mixed- signal applications are presented.Extrinsic cut-off frequencies of ft =293 GHz and fmax =337 GHz were achieved for a 70 nm gate length metamorphic HEMT echnology.The MMIC process obtains high yield on transistor and circuit level.Single-stage low-noise amplifiers demonstrate a small signal gain of 13 dB and a noise figure of 2.8 dB at 94 GHz.An amplifier MMIC developed for D-Band operation features a gain of 15 dB at 160 GHz.The achieved results are comparable to state- of-the-art InP-based HEMT technologies.In order to realize 80 Gbit/s digital circuits,a process with 100 nm gate length enhancement type HEMTs with a transit frequency of 200 GHz is used.Three metalization layers are available for interconnects.The parasitic capacitance of the interconnects is kept low by using BCB and plated air bridge technology.Based on this process,static and dynamic frequency dividers achieve a maximu toggle frequency of 70 GHz and 108 GHz,respectively

Electron transport and optical properties of shallow GaAs/InGaAs/GaAs quantum wells with a thin central AlAs barrier

Shallow GaAs/InGaAs/GaAs quantum well structures with and without a three monolayer thick AlAs central barrier have been investigated for different well widths and Si doping levels. The transport parameters are determined by resistivity measurements in the temperature range 4-300 K and magnetotransport in magnetic fields up to 12 T. The (subband) carrier concentrations and mobilities are extracted from the Hall data and Shubnikov-de Haas oscillations. We find that the transport parameters are strongly affected by the insertion of the AlAs central barrier. Photoluminescence spectra, measured at 77 K, show an increase of the transition energies upon insertion of the barrier. The transport and optical data are analyzed with help of self-consistent calculations of the subband structure and envelope wave functions. Insertion of the AlAs central barrier changes the spatial distribution of the electron wave functions and leads to the formation of hybrid states, i.e. states which extend over the InGaAs and the delta-doped layer quantum wells.Comment: 14 pages, pdf fil

DNA double-strand break resection occurs during non-homologous end joining in G1 but is distinct from resection during homologous recombination

Canonical non-homologous end joining (c-NHEJ) repairs DNA double-strand breaks (DSBs) in G1 cells with biphasic kinetics. We show that DSBs repaired with slow kinetics, including those localizing to heterochromatic regions or harboring additional lesions at the DSB site, undergo resection prior to repair by c-NHEJ and not alt-NHEJ. Resection-dependent c-NHEJ represents an inducible process during which Plk3 phosphorylates CtIP, mediating its interaction with Brca1 and promoting the initiation of resection. Mre11 exonuclease, EXD2, and Exo1 execute resection, and Artemis endonuclease functions to complete the process. If resection does not commence, then repair can ensue by c-NHEJ, but when executed, Artemis is essential to complete resection-dependent c-NHEJ. Additionally, Mre11 endonuclease activity is dispensable for resection in G1. Thus, resection in G1 differs from the process in G2 that leads to homologous recombination. Resection-dependent c-NHEJ significantly contributes to the formation of deletions and translocations in G1, which represent important initiating events in carcinogenesis