1,528 research outputs found
Supersymmetric Yang-Mills, octonionic instantons and triholomorphic curves
In four-dimensional gauge theory there exists a well-known correspondence
between instantons and holomorphic curves, and a similar correspondence exists
between certain octonionic instantons and triholomorphic curves. We prove that
this latter correspondence stems from the dynamics of various dimensional
reductions of ten-dimensional supersymmetric Yang-Mills theory. More precisely
we show that the dimensional reduction of the (5+1)-dimensional supersymmetric
sigma model with hyperkaehler (but otherwise arbitrary) target X to a
four-dimensional hyperkaehler manifold M is a topological sigma model
localising on the space of triholomorphic maps M -> X (or hyperinstantons).
When X is the moduli space M_K of instantons on a four-dimensional hyperkaehler
manifold K, this theory has an interpretation in terms of supersymmetric gauge
theory. In this case, the topological sigma model can be understood as an
adiabatic limit of the dimensional reduction of ten-dimensional supersymmetric
Yang-Mills on the eight-dimensional manifold M x K of holonomy Sp(1) x Sp(1) in
Spin(7), which is a cohomological theory localising on the moduli space of
octonionic instantons.Comment: 26 pages, LaTeX2e (A comment and a corresponding acknowledgement
added and a reference ammended
Astrophysically sourced quantum coherent photonic signals
Stimulated emission is shown to be robust in stars. Through Bose enhancement
this produces quantum states of aligned, monochromatic photons similar to a
laser. The probability of creating such states is computed. We show that from
the solar corona such quantum states would propagate outside of the solar
region and through the Solar System without decoherence. For a
detector at the distance of the Earth from the Sun we estimate rates of such
quantum states in the few per second thus potentially detectable. The same
process should lead to such quantum states also arriving from stars at
interstellar distances.Comment: 5 page
Acciones de la mezcla de marketing verde incorporadas en medianas y grandes empresas para desarrollar una ventaja competitiva, registradas en artículos científicos desde el año 2001 al 2015 - Una revisión literaria
Este trabajo de investigación aborda una perspectiva teórica con respecto a las acciones
de la mezcla de marketing verde que han incorporado las medianas y grandes empresas para
desarrollar una ventaja competitiva. Este estudio al ser una revisión de literatura se basa en el
repaso y reconstrucción de trabajos ya realizados por otros investigadores, este tiene como fin
detectar, obtener, consultar bibliografías y otros materiales que son útiles para su desarrollo.
En la investigación se utilizó la metodología prisma, y también una matriz de registro para el
análisis de la bibliografía escogida. En la revisión literaria presentada se consideraron artículos
científicos latinoamericanos y europeos, que van desde el año 2001 hasta el 2015.Al final de
la investigación se evidencian las buenas prácticas relacionadas a la mezcla de marketing verde
y como estas pueden mantener una diferenciación, generando así una ventaja sostenible y
competitiva
Cohomological Yang-Mills Theories on Kahler 3-Folds
We study topological gauge theories with N=(2,0) supersymmetry based on
stable bundles on general Kahler 3-folds. In order to have a theory that is
well defined and well behaved, we consider a model based on an extension of the
usual holomorphic bundle by including a holomorphic 3-form. The correlation
functions of the model describe complex 3-dimensional generalizations of
Donaldson-Witten type invariants. We show that the path integral can be written
as a sum of contributions from stable bundles and a complex 3-dimensional
version of Seiberg-Witten monopoles. We study certain deformations of the
theory, which allow us to consider the situation of reducible connections. We
shortly discuss situations of reduced holonomy. Afterdimensional reduction to a
Kahler 2-fold, the theory reduces to Vafa-Wittentheory. On a Calabi-Yau 3-fold,
the supersymmetry is enhanced to N=(2,2). This model may be used to describe
classical limits of certain compactifications of(matrix) string theory.Comment: 32 pages, LaTe
GaHV-2 ICP22 protein is expressed from a bicistronic transcript regulated by three GaHV-2 microRNAs
International audienceHerpesviruses have a lifecycle consisting of successive lytic, latent and reactivation phases. Only three infected cell proteins (ICPs) have been described for the oncogenic Marek's disease virus (or Gallid herpes virus 2, GaHV-2): ICP4, ICP22 and ICP27. We focus here on ICP22, confirming its cytoplasmic location and showing that ICP22 is expressed during productive phases of the lifecycle, via a bicistronic transcript encompassing the US10 gene. We also identified the unique promoter controlling ICP22 expression, and its core promoter, containing functional responsive elements including E-box, ETS-1 and GATA elements involved in ICP22 transactivation. ICP22 gene expression was weakly regulated by DNA methylation and activated by ICP4 or ICP27 proteins. We also investigated the function of GaHV-2 ICP22. We found that this protein repressed transcription from its own promoter and from those of IE ICP4 and ICP27, and the late gK promoter. Finally, we investigated posttranscriptional ICP22 regulation by GaHV-2 microRNAs. We found that mdv1-miR-M5-3p and -M1-5p downregulated ICP22 mRNA expression during latency, whereas, unexpectedly, mdv1-miR-M4-5p upregulated the expression of the protein ICP22, indicating a tight regulation of ICP22 expression by microRNAs
Spatio-temporal assessment of WRF, TRMM and in situ precipitation data in a tropical mountain environment (Cordillera Blanca, Peru)
The estimation of precipitation over the broad range of scales of interest for climatologists, meteorologists and hydrologists is challenging at high altitudes of tropical regions, where the spatial variability of precipitation is important while in situ measurements remain scarce largely due to operational constraints. Three different types of rainfall products - ground based (kriging interpolation), satellite derived (TRMM3B42), and atmospheric model outputs (WRF - Weather Research and Forecasting) - are compared for 1 hydrological year in order to retrieve rainfall patterns at timescales ranging from sub-daily to annual over a watershed of approximately 10 000 km(2) in Peru. An ensemble of three different spatial resolutions is considered for the comparison (27, 9 and 3 km), as long as well as a range of timescales (annual totals, daily rainfall patterns, diurnal cycle). WRF simulations largely overestimate the annual totals, especially at low spatial resolution, while reproducing correctly the diurnal cycle and locating the spots of heavy rainfall more realistically than either the ground-based KED or the Tropical Rainfall Measuring Mission (TRMM) products. The main weakness of kriged products is the production of annual rainfall maxima over the summit rather than on the slopes, mainly due to a lack of in situ data above 3800 ma.s.l. This study also confirms that one limitation of TRMM is its poor performance over ice-covered areas because ice on the ground behaves in a similar way as rain or ice drops in the atmosphere in terms of scattering the microwave energy. While all three products are able to correctly represent the spatial rainfall patterns at the annual scale, it not surprisingly turns out that none of them meets the challenge of representing both accumulated quantities of precipitation and frequency of occurrence at the short timescales (sub-daily and daily) required for glacio-hydrological studies in this region. It is concluded that new methods should be used to merge various rainfall products so as to make the most of their respective strengths
- …