Heterotic Non-Kahler Geometries via Polystable Bundles on Calabi-Yau Threefolds

In arXiv:1008.1018 it is shown that a given stable vector bundle $V$ on a Calabi-Yau threefold $X$ which satisfies $c_2(X)=c_2(V)$ can be deformed to a solution of the Strominger system and the equations of motion of heterotic string theory. In this note we extend this result to the polystable case and construct explicit examples of polystable bundles on elliptically fibered Calabi-Yau threefolds where it applies. The polystable bundle is given by a spectral cover bundle, for the visible sector, and a suitably chosen bundle, for the hidden sector. This provides a new class of heterotic flux compactifications via non-Kahler deformation of Calabi-Yau geometries with polystable bundles. As an application, we obtain examples of non-Kahler deformations of some three generation GUT models.Comment: 12 pages, late

Siglec receptors impact mammalian lifespan by modulating oxidative stress.

Aging is a multifactorial process that includes the lifelong accumulation of molecular damage, leading to age-related frailty, disability and disease, and eventually death. In this study, we report evidence of a significant correlation between the number of genes encoding the immunomodulatory CD33-related sialic acid-binding immunoglobulin-like receptors (CD33rSiglecs) and maximum lifespan in mammals. In keeping with this, we show that mice lacking Siglec-E, the main member of the CD33rSiglec family, exhibit reduced survival. Removal of Siglec-E causes the development of exaggerated signs of aging at the molecular, structural, and cognitive level. We found that accelerated aging was related both to an unbalanced ROS metabolism, and to a secondary impairment in detoxification of reactive molecules, ultimately leading to increased damage to cellular DNA, proteins, and lipids. Taken together, our data suggest that CD33rSiglecs co-evolved in mammals to achieve a better management of oxidative stress during inflammation, which in turn reduces molecular damage and extends lifespan

Genetic diversity and character association analysis based on pomological traits in olive (Olea europaea L.)

Thirteen exotic genotypes of olive (Olea europaea L.) were studied for the genetic variability, correlation and path coefficient analysis for fruit quality, yield and yield contributing traits at experimental farm of ICAR-CITH, Srinagar during 2009-2013. Maximum variability was recorded for fruit yield and oil content, however, low differ-ences between the phenotypic and genotypic coefficients of variations indicated low environmental influences on the expression of these characters. High heritability coupled with high genetic advance was obtained with fruit yield per plant, acidity, fruit pulp weight, fruit weight and stone weight. Fruit weight (r=0.329), stone weight (r=0.405) and oil content (r=0.841) were the most important traits, which possessed significant positive association with fruit yield per plant. Path coefficient analysis revealed that among the different yield contributing characters oil content (0.875), fruit weight (0.797) followed by acidity (0.501), peroxides value ( 0.199) and fruit length (0.054) influenced fruit yield per plant directly. The direct effects of these characters on fruit yield were found positive and considerably very high.The selection based on fruit weight, stone weight oil content and yield per plant will be effective for enhancing the fruit and oil yieldand making future olive breeding strategies

Form Finding and structural Optimization of Tensile cable dome using Parametric Modelling Tools

In this paper, a new framework of form finding and structural optimizations for tensile domes was developed using a cutting-edge parametric modelling tool Grasshopper in Rhino. The detailed exploration of this new techniques is presented. It is found that the use of this parametric tool allows a more intuitive, rapid and flexible design. Structural optimisation of the member sizes, topology and surface can be explored easily at an initial design stage in a project. Therefore, the proposed new framework provides a more effective and efficient way for form finding and structural optimization. Based on the new method, a prototype Tensile dome which is to replicate the existing Tensile Dome Georgia dome is designed and analyzed. The structural behavior of the cable domes is investigated. Using this new framework, two ellipse shape Tensile domes with new geometrical configuration are developed. They exhibit enhanced load bearing capacity, therefore can be used the future long span structure projects

Solutions of the Strominger System via Stable Bundles on Calabi-Yau Threefolds

We prove that a given Calabi-Yau threefold with a stable holomorphic vector bundle can be perturbed to a solution of the Strominger system provided that the second Chern class of the vector bundle is equal to the second Chern class of the tangent bundle. If the Calabi-Yau threefold has strict SU(3) holonomy then the equations of motion derived from the heterotic string effective action are also satisfied by the solutions we obtain.Comment: 19 pages, late

Novel ZnO nanorod films by chemical solution deposition for planar device applications

: Smooth and continuous ZnO films consisting of densely packed ZnO nanorods (NRs) were synthesized using hydro-thermo-chemical solution deposition method which can be used for electronic device fabrication. These devices would have the novelty of high performance benefiting from the unique properties of the nanomaterials and can be fabricated on these films using conventional low cost planar process, as they have very smooth surfaces. Photoluminescence measurements showed that the nanorod films have much stronger band-to-band emissions than those from discrete ZnO NRs, hence have the potential for the development of ZnO light emission diodes and lasers etc. The nanorod films have been used to fabricate large area planar surface acoustic wave devices by conventional photolithography and demonstrated two well-defined resonant peaks and their potential for large area device applications. The chemical solution deposition method is a simple, reproducible, scalable and economic method. These nanorod films are suitable for large scale production and synthesis on cost-effective substrates promising for various fields such as sensing systems, renewable energy and optoelectronic applications

Construction of innovation : contributions of tecnosinos in the city of São Leopoldo

Os parques científicos e tecnológicos constituem-se, nos seus diferentes modelos e arranjos, em destacada estratégia para a construção da inovação, experimentando expressiva expansão tanto nos países desenvolvidos quanto nos emergentes, em décadas recentes. A proposta do artigo é explorar efeitos da implantação do TECNOSINOS no desenvolvimento produtivo na cidade de São Leopoldo. Os dados resultam de pesquisa exploratória realizada junto à bibliografia especializada e à documentação disponível na internet, além de depoimentos colhidos em visitas realizadas ao Parque e sua incubadora. Constata-se que a formação do parque resulta de um contexto em que se combina a experiência institucional do Programa Porto Alegre Tecnópole, nos anos 1990, e a crise da indústria coureiro-calçadista que obrigou a cidade e região a buscar alternativas de desenvolvimento econômico e social, no mesmo período. A implantação e evolução do parque implicaram em mudanças na própria universidade e na expansão da importância das empresas e empregos no setor de informática na cidade.Scientific and technological parks are, in their different models and arrangements, an outstanding strategy for the construction of innovation, experiencing significant expansion in developed and emerging countries in recent decades. The purpose of this article is to explore the effects of the implementation of TECNOSINOS in the productive development in the city of São Leopoldo. The data are the result of an exploratory research carried with the specialized bibliography and the documentation available on the Internet, as well as testimonies collected on visits to the Park and its incubator. It can be seen that the formation of the park results from a context which combined in the 1990s the institutional experience of the Porto Alegre Tecnopolis Program and the crisis of the leather-footwear industry, which forced the city and region to seek alternatives for economic and in the same period. The implantation and evolution of the park implied in changes in the own university and in the expansion of the importance of the companies and jobs in the sector of informatics in the city

A noniterative design procedure for supplemental brace-damper systems in single-degree-of-freedom systems

SUMMARY: In this paper, a method for designing supplemental brace-damper systems in single-degree-of-freedom (SDOF) structures is presented. We include the effects of the supporting brace stiffness in the dynamic response by using a viscoelastic Maxwell model. On the basis of the study of an SDOF under ground excitation, we propose a noniterative design procedure for simultaneously specifying both the damper and the brace while assuring a desired structural performance. It is shown that to increase the damper size beyond the value delivered by the proposed criteria will not provide any improvement but actually worsen the structural response. The design method presented here shows excellent agreement with the FEMA 273 design approach but offers solutions closer to optimality. © 2013 John Wiley & Sons, Ltd

CFHTLS weak-lensing constraints on the neutrino masses

We use measurements of cosmic shear from CFHTLS, combined with WMAP-5 cosmic microwave background anisotropy data, baryonic acoustic oscillations from SDSS and 2dFGRS and supernovae data from SNLS and Gold-set, to constrain the neutrino mass. We obtain a 95% confidence level upper limit of 0.54 eV for the sum of the neutrino masses, and a lower limit of 0.03 eV. The preference for massive neutrinos vanishes when shear-measurement systematics are included in the analysis.Comment: 10 pages. Published versio

Epitaxially strained [001]-(PbTiO3_3)1_1(PbZrO3_3)1_1 superlattice and PbTiO3_3 from first principles

The effect of layer-by-layer heterostructuring and epitaxial strain on lattice instabilities and related ferroelectric properties is investigated from first principles for the [001]-(PbTiO$_3$)$_1$(PbZrO$_3$)$_1$ superlattice and pure PbTiO$_3$ on a cubic substrate. The results for the superlattice show an enhancement of the stability of the monoclinic r-phase with respect to pure PbTiO$_3$. Analysis of the lattice instabilities of the relaxed centrosymmetric reference structure computed within density functional perturbation theory suggests that this results from the presence of two unstable zone-center modes, one confined in the PbTiO$_3$ layer and one in the PbZrO$_3$ layer, which produce in-plane and normal components of the polarization, respectively. The zero-temperature dielectric response is computed and shown to be enhanced not only near the phase boundaries, but throughout the r-phase. Analysis of the analogous calculation for pure PbTiO$_3$ is consistent with this interpretation, and suggests useful approaches to engineering the dielectric properties of artificially structured perovskite oxides.Comment: 8 pages, 5 figure