Calculation of supersonic viscous flow over delta wings with sharp subsonic leading edges

Two complementary procedures were developed to calculate the viscous supersonic flow over conical shapes at large angles of attack, with application to cones and delta wings. In the first approach the flow is assumed to be conical and the governing equations are solved at a given Reynolds number with a time-marching explicit finite-difference algorithm. In the second method the parabolized Navier-Stokes equations are solved with a space-marching implicit noniterative finite-difference algorithm. This latter approach is not restricted to conical shapes and provides a large improvement in computational efficiency over published methods. Results from the two procedures agree very well with each other and with available experimental data

Light transmission assisted by Brewster-Zennek modes in chromium films carrying a subwavelength hole array

This work confirms that not only surface plasmons but many other kinds of electromagnetic eigenmodes should be considered in explaining the values of the transmittivity through a slab bearing a two-dimensional periodic corrugation. Specifically, the role of Brewster-Zennek modes appearing in metallic films exhibiting regions of weak positive dielectric constant. It is proposed that these modes play a significant role in the light transmission in a thin chromium film perforated with normal cylindrical holes, for appropriate lattice parameters.Comment: 5 pages, 4 figures. Published versio

Microstructure Bio-Material for Behavioral Analysis

Biological applications have a limitation of creating tissue like structures in order to mimic the advanced real like structures, such as human tissues in a small scale. Conventional methods of using lab mice for cancer behavior have limitations due to observation complications. Fabricating an artificial human tissue which can behave similar to a human body tissue consists of components, such as Laminin and Collagen. Collagen in human tissue has elements, such as integrin and serum. Creating serum based proteins are somewhat challenging due to the conditional requirements. This particular approach will address the primary state of the art technique of observing the interaction with cells by mimicking the organs on a chip with blood circulation using a micro-fluidic pump. Bio-material hydrogel structures implanted on a silicon polymer based chip described in this thesis will overcome the limitations of in-vitro analysis. Water purification has become a vital issue in developing countries of the world. Water pollution due to Ammonia has been one of the major concerns with industrial revolution. Purifications were mainly done by chemical methods that can cause human health concerns. The analytically demonstrated method in this thesis using bio-compatible hydrogel will address a new dimension to the water conservation method without causing health issues and eliminating the environmental pollution due to complicated degradable structures. Filtration and efficiency are among the main concerns of using bacteria types such as AOB/NOB directly without encapsulating. Application of using bio-compatible hydrogel based dual encapsulated single pallet structure described in this thesis will address the issue of filtering capability. Pallets can be removed once nitrified, without letting it grow inside the water contaminating aqua based living breads and plants. The process will improve the efficiency of Ammonia removal due to encapsulation. Drug delivery using micro locomotives in neuro-surgery has become one of the future concerns with the development of science. Conventional delivery systems such as vaccines and open surgeries take longer response time once surgeries become more complex. Moreover there is a risk factor of injuring healthy nerves in the organ. Drug delivery approaches of drug encapsulated microspheres and drug embedded nematodes described in this thesis become more applicable to complex scenarios. Nematodes become useful in the future of microsurgeries, as many biologists are focusing on using their healthy nerves to implant in humans. Therefore, such applications like magnetizing nematodes help move locomotives to targeted locations and capture scan images for future medical approaches

Fluid force and symmetry breaking modes of a 3D bluff body with a base cavity

International audienceA cavity at the base of the squareback Ahmed model at Re 4 × 10 5 is able to reduce the base suction by 18% and the drag coefficient by 9%, while the geometry at the separation remains unaffected. Instantaneous pressure measurements at the body base, fluid force measurements and wake velocity measurements are investigated varying the cavity depth from 0 to 35% of the base height. Due to the reflectional symmetry of the rectangular base, there are two Reflectional Symmetry Breaking (RSB) mirror modes present in the natural wake that switch from one to the other randomly in accordance with the recent findings of Grandemange et al. (2013b). It is shown that these modes exhibit an energetic 3D static vortex system close to the base of the body. A sufficiently deep cavity is able to stabilize the wake toward a symmetry preserved wake, thus suppressing the RSB modes and leading to a weaker elliptical toric recirculation. The stabilization can be modelled with a Langevin equation. The plausible mechanism for drag reduction with the base cavity is based on the interaction of the static 3D vortex system of the RSB modes with the base and their suppression by stabilization. There are some strong evidences that this mechanism may be generalized to axisym-metric bodies with base cavity

Gene flow estimation with microsatellites in a Malagasy seed orchard of Eucalyptus grandis

International audienceEucalyptus grandis has a mixed-mating repro- ductive system. Malagasy Eucalyptus seed orchards were established 15 years ago with two aims both based on panmixia: open-pollinated seed production and genetic improvement. The panmixia hypothesis has never been confirmed in the seed orchard. From a seedling seed- orchard stand comprising 349 trees and using data obtained with six selected microsatellite markers, pater- nity analysis was performed for 724 offspring collected on 30 adult trees. Paternity assignment, based on exclu- sion procedures and likelihood-ratio method, was achieved with high accuracy; the exclusion probability value was 0.997. The outcrossing rate was very high (96.7%). More than 50% of potential male trees (199 out of 349) in the seed orchard contributed to pollination for 440 offspring of 30 progenies (8.6% of the basic population). The pollination rate from outside the seed orchard was high (39.2%), but might be due to the small size of this seed orchard. This study showed that "panmixia-like pollination" can be assume

Distinct regions of RPB11 are required for heterodimerization with RPB3 in human and yeast RNA polymerase II

In Saccharomyces cerevisiae, RNA polymerase II assembly is probably initiated by the formation of the RPB3–RPB11 heterodimer. RPB3 is encoded by a single copy gene in the yeast, mouse and human genomes. The RPB11 gene is also unique in yeast and mouse, but in humans a gene family has been identified that potentially encodes several RPB11 proteins differing mainly in their C-terminal regions. We compared the abilities of both yeast and human proteins to heterodimerize. We show that the yeast RPB3/RPB11 heterodimer critically depends on the presence of the C-terminal region of RPB11. In contrast, the human heterodimer tolerates significant changes in RPB11 C-terminus, allowing two human RPB11 variants to heterodimerize with the same efficiency with RPB3. In keeping with this observation, the interactions between the conserved N-terminal ‘α-motifs’ is much more important for heterodimerization of the human subunits than for those in yeast. These data indicate that the heterodimerization interfaces have been modified during the course of evolution to allow a recent diversification of the human RPB11 subunits that remains compatible with heterodimerization with RPB3

Nonlinear Blind Parameter Estimation

This note deals with parameter estimation of nonlinear continuous-time models when the input signals of the corresponding system are not measured. The contribution of the note is to show that, with simple priors about the unknown input signals and using derivatives of the output signals, one can perform the estimation procedure. As an illustration, we consider situations where the simple priors, e.g., independence or Gaussianity of the unknown inputs, is assumed

Une Approche par Décomposition pour la Découverte de Motifs sur Données Séquentielles

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A human RNA polymerase II subunit is encoded by a recently generated multigene family

BACKGROUND: The sequences encoding the yeast RNA polymerase II (RPB) subunits are single copy genes. RESULTS: While those characterized so far for the human (h) RPB are also unique, we show that hRPB subunit 11 (hRPB11) is encoded by a multigene family, mapping on chromosome 7 at loci p12, q11.23 and q22. We focused on two members of this family, hRPB11a and hRPB11b: the first encodes subunit hRPB11a, which represents the major RPB11 component of the mammalian RPB complex ; the second generates polypeptides hRPB11bα and hRPB11bβ through differential splicing of its transcript and shares homologies with components of the hPMS2L multigene family related to genes involved in mismatch-repair functions (MMR). Both hRPB11a and b genes are transcribed in all human tissues tested. Using an inter-species complementation assay, we show that only hRPB11bα is functional in yeast. In marked contrast, we found that the unique murine homolog of RPB11 gene maps on chromosome 5 (band G), and encodes a single polypeptide which is identical to subunit hRPB11a. CONCLUSIONS: The type hRPB11b gene appears to result from recent genomic recombination events in the evolution of primates, involving sequence elements related to the MMR apparatus

A Decomposition Approach for Discovering Discriminative Motifs in a Sequence Database

Short paperInternational audienceThis paper addresses the discovery of discriminative nary motifs in databases of labeled sequences. We consider databases made up of positive and negative sequences and define a motif as a set of patterns embedded in all positive sequences and subject to alignment constraints. We formulate constraints to eliminate redundant motifs and present a general constraint optimization framework to compute motifs that are exclusive to the positive sequences. We cast the discovery of closed and replication-free motifs in this framework and propose a two-stage approach whose last stage reduces to a minimum set covering problem. Experiments on protein sequence datasets demonstrate its efficiency