Renormalized Wick expansion for a modified PQCD

The renormalization scheme for the Wick expansion of a modified version of the perturbative QCD introduced in previous works is discussed. Massless QCD is considered, by implementing the usual multiplicative scaling of the gluon and quark wave functions and vertices. However, also massive quark and gluon counter-terms are allowed in this mass less theory since the condensates are expected to generate masses. A natural set of expansion parameters of the physical quantities is introduced: the coupling itself and to masses $m_q$ and $m_g$ associated to quarks and gluons respectively. This procedure allows to implement a dimensional transmutation effect through these new mass scales. A general expression for the new generating functional in terms of the mass parameters $m_q$ and $m_g$ is obtained in terms of integrals over arbitrary but constant gluon or quark fields in each case. Further, the one loop potential, is evaluated in more detail in the case when only the quark condensate is retained. This lowest order result again indicates the dynamical generation of quark condensates in the vacuum.Comment: 13 pages, one figur

Classical Noncommutative Electrodynamics with External Source

In a $U(1)_{\star}$-noncommutative (NC) gauge field theory we extend the Seiberg-Witten (SW) map to include the (gauge-invariance-violating) external current and formulate - to the first order in the NC parameter - gauge-covariant classical field equations. We find solutions to these equations in the vacuum and in an external magnetic field, when the 4-current is a static electric charge of a finite size $a$, restricted from below by the elementary length. We impose extra boundary conditions, which we use to rule out all singularities, $1/r$ included, from the solutions. The static charge proves to be a magnetic dipole, with its magnetic moment being inversely proportional to its size $a$. The external magnetic field modifies the long-range Coulomb field and some electromagnetic form-factors. We also analyze the ambiguity in the SW map and show that at least to the order studied here it is equivalent to the ambiguity of adding a homogeneous solution to the current-conservation equation

Photon emission as a source of coherent behaviour of polaritons

We show that the combined effect of photon emission and Coulomb interactions may drive an exciton-polariton system towards a dynamical coherent state, even without phonon thermalization or any other relaxation mechanism. Exact diagonalization results for a finite system (a multilevel quantum dot interacting with the lowest energy photon mode of a microcavity) are presented in support to this statement

Sintering anisotropy of binder jetted 316L stainless steel: part II–microstructure evolution during sintering

Green density of binder jetted parts are typically equal or lower than the powder tap density. Also, anisotropic green porosity distribution is expected because of the characteristics of the binder jetting (BJ) printing process. In this study, the microstructure evolution in terms of phases and porosity characteristics was studied. A transition from irregular-shape interconnected porosity in pre-sintered samples to closed quasi-spherical porosity for samples sintered at 1370\ub0C was observed. EBSD phase map showed ∼2.73% of δ-ferrite in sample sintered at 1370\ub0C. The anisotropic porosity distribution was revealed by a higher area fraction of aligned large pores (>35 \ub5m), within the cross-section perpendicular to the building direction. Chemical analysis showed an increase of C, O and N on the green sample, while a strong decrease was found after sintering when compared with the powder chemistry. δ-ferrite onset, from phase equilibrium calculations, varies from ∼1250\ub0C (sintered sample chemistry) to ∼1350\ub0C (powder chemistry)

Sintering anisotropy of binder jetted 316L stainless steel: part I–sintering anisotropy

In Binder Jetting (BJ) Additive Manufacturing (AM), green components are usually subjected to sintering process to reach required properties. Owing to the inherent low green density, binder jetted (BJ) parts undergo shrinkages up to 20%. In addition, anisotropic dimensional evolution during sintering is characteristic for BJ, generally caused by the specifics of the arrangement of particles during the printing process. In this study, the multi-axial dimensional evolution of 316L stainless steel cubic samples (10 7 10 7 10 mm3), manufactured using BJ, was characterised by dilatometry experiments. Dilatometry tests were conducted up to sintering temperatures of 1300\ub0C and 1370\ub0C, with a heating rate of 10\ub0C/min and 5\ub0C/min, respectively. Dilatometry results and final dimension measurements showed anisotropic shrinkage behaviour during sintering with about 15% larger shrinkage along the building direction. Shrinkages along the other two orthogonal directions were relatively similar, but a slightly larger final shrinkage along the printhead movement direction was observed. Relative density of 85.0% and 96.4% was obtained after sintering tests at 1300\ub0C and 1370\ub0C, respectively

Quantization of massive scalar fields over static black string backgrounds

The renormalized mean value of the corresponding components of the Energy-Momentum tensor for massive scalar fields coupled to an arbitrary gravitational field configuration having cylindrical symmetry are analytically evaluated using the Schwinger-DeWitt approximation, up to second order in the inverse mass value. The general results are employed to explicitly derive compact analytical expressions for the Energy-Momentum tensor in the particular background of the Black-String spacetime. In the case of the Black String considered in this work, we proof that a violation of the weak energy condition occur at the horizon of the space-time for values of the coupling constant, that include as particular cases the most interesting of minimal and conformal coupling.Comment: 4 page

Estudio microscópico de la hoja de thymus baeticus boiss. Ex lacaita in vivo e in vitro

We performed an histologic study comparing "in vivo" and "in vitro" leaves of Thymus baeticus Boiss. ex Lacai ta. "In vitro" leaves were obtained through organ culture, whereas wild material -"in vivo" leaves- was collected in Lanjar6n (Granada, España) . Both samples showed similar oil-glands, which resembled the general pattern in Labiatae; however, we noticed remarkable differences as far as shape and hairs were concerned. These facts are thought to be caused by the environment: cultured plants grow in optimum conditions, so they do not develope their defensive mechanism as much as wild plants do. These conclusions are reinforced by the study of powdered l eaves .Hemos realizado un estudio histológico de las hojas de Thymus baeticus Boiss. ex Lacaita, tanto "in vivo" como "in vitro". Para el esLudio de las hojas "in vitro" se utilizaron las procedentes de cultivo de órganos. En cambio las hojas "in vivo" fueron las recolectadas en Lanjarón (Granada). Ambas muestras poseen glándulas oleosas similares, que recuerdan el tipo general de las Labiatae; en cambio, hemos observado notables diferencias en cuanto a los pelos. Se estima que este hecho se debe al entorno: las plantas cultivadas crecen en condiciones óptimas, por lo que no desarrollan sus mecanismos de defensa, como han de hacerlo las plantas silvestres. Estas conclusiones se ven reforzadas por el estudio de las hojas en polvo

Estudio microscópico de la hoja de thymus baeticus boiss. Ex lacaita in vivo e in vitro

Hemos realizado un estudio histológico de las hojas de Thymus baeticus Boiss. ex Lacaita, tanto "in vivo" como "in vitro". Para el esLudio de las hojas "in vitro" se utilizaron las procedentes de cultivo de órganos. En cambio las hojas "in vivo" fueron las recolectadas en Lanjarón (Granada). Ambas muestras poseen glándulas oleosas similares, que recuerdan el tipo general de las Labiatae; en cambio, hemos observado notables diferencias en cuanto a los pelos. Se estima que este hecho se debe al entorno: las plantas cultivadas crecen en condiciones óptimas, por lo que no desarrollan sus mecanlsmos de defensa, como han de hacerlo las plantas silvestres. Estas conclusiones se ven reforzadas por el estudio de las hojas en polvo.We performed an histologic study comparing "in vivo" and "in vi tro" leaves of Thymus baeticus Boiss. ex Lacai ta. "In vi tro" leaves were obtained through organ culture, whereas wild material -"in vivo" leaves- was collected in Lanjar6n (Granada, Espa ña) . Both samples showed similar oil-glands, which resembled the general pattern in Labiatae; however, we noticed remarkable differences as far as shape and hairs were concerned. These facts are thought to be caused by the environment: cultured plants grow in optimum conditions, so they do not develope their defensive mechanism as much as wild plants do. These conclusions are reinforced by the study of powdered l eaves

On the uniqueness of the surface sources of evoked potentials

The uniqueness of a surface density of sources localized inside a spatial region $R$ and producing a given electric potential distribution in its boundary $B_0$ is revisited. The situation in which $R$ is filled with various metallic subregions, each one having a definite constant value for the electric conductivity is considered. It is argued that the knowledge of the potential in all $B_0$ fully determines the surface density of sources over a wide class of surfaces supporting them. The class can be defined as a union of an arbitrary but finite number of open or closed surfaces. The only restriction upon them is that no one of the closed surfaces contains inside it another (nesting) of the closed or open surfaces.Comment: 16 pages, 5 figure

3D morphological features and antibiotic resistance in L. monocytogenes - Pseudomonas sp. biofilms

1 poster presented at Biofilms 7, Porto, 26-28 June 2016This research was financially supported by the Spanish Research Council (Project ref.201670 E008)N