On the relationship between pump chirp and single-photon chirp in spontaneous parametric downconversion

We study the chronocyclic character, i.e. the joint temporal and spectral properties, of the single-photon constituents of photon pairs generated by spontaneous parametric down conversion. In particular we study how single photon properties, including purity and single-photon chirp, depend on photon pair properties, including the type of signal-idler spectral and correlations and the level of pump chirp.Comment: 13 pages, 6 figure

Chiral Perturbation Theory with tensor sources

We construct the most general chirally-invariant Lagrangian for mesons in the presence of external sources coupled to the tensor current \bar{\psi}\sigma_{\mu\nu}\psi. In order to have only even terms in the chiral expansion, we consider the new source of O(p^2). With this choice, we build the even-parity effective Lagrangian up to the p^6-order (NLO). While there are only 4 new terms at the p^4-order, at p^6-order we find 78 terms for n_f=2 and 113 terms for n_f=3. We provide a detailed discussion on the different mechanisms that ensure that our final set of operators is complete and non-redundant. We also examine the odd-parity sector, to conclude that the first operators appear at the p^8-order (NNLO).Comment: 23 pages, one figure; typos corrected, one paragraph added, new section added, references added, published versio

Image inpainting

Trabajo presentado en la 27th Annual Conference on Computer Graphics and Interactive TechniquesInpainting, the technique of modifying an image in an undetectable form, is as ancient as art itself. The goals and applications of inpainting are numerous, from the restoration of damaged paintings and photographs to the removal/replacement of selected objects. In this paper, we introduce a novel algorithm for digital inpainting of still images that attempts to replicate the basic techniques used by professional restorators. After the user selects the regions to be restored, the algorithm automatically fills-in these regions with information surrounding them. The fill-in is done in such a way that isophote lines arriving at the regions’ boundaries are completed inside. In contrast with previous approaches, the technique here introduced does not require the user to specify where the novel information comes from. This is automatically done (and in a fast way), thereby allowing to simultaneously fill-in numerous regions containing completely different structures and surrounding backgrounds. In addition, no limitations are imposed on the topology of the region to be inpainted. Applications of this technique include the restoration of old photographs and damaged film; removal of superimposed text like dates, subtitles, or publicity; and the removal of entire objects from the image like microphones or wires in special effects

Influenza em suínos no Brasil: o problema e o que pode ser feito para manter a infecção controlada nas granjas afetadas.

Projeto/Plano de Ação: 03.07.05.019

Los recursos documentales del Servicio de Información sobre Discapacidad : Documentary sources in the Service of Information on Disability

En este artículo mostramos el contenido de una de las secciones que conforman el Servicio de Información sobre Discapacidad (SID), la de Fuentes Documentales, centrándonos en las tesis y artículos de revistas por considerarlas de mayor interés por su profundidad de análisis, investigación y actualidad. Como ayuda en la búsqueda de información se realizan una serie de productos, como son dossieres documentales, que van a agrupar la información temáticamente, vaciados de diferentes revistas, que nos ofrecen el contenido de las revistas científicas españolas.This article discusses the contents of the Document sources of the Information Service on Disability (DIS) which focuses on dissertations and journal articles as these are considered to be of greater interest on account of their depth of analysis and research and their currency. A series of products are elaborated as information search aids: dossiers of documents grouped according to subject from different journals which offer the contents of the most relevant Spanish scientific journals on disabilities; a quarterly contents page bulletin giving the indexes of the most relevant national and international scientific journals. Thematic grouping of dossiers is carried out according to user demand and reports on issues suggested by users are also prepared periodically

Gravitational waves from galaxy encounters

We discuss the emission of gravitational radiation produced in encounters of dark matter galactic halos. To this aim we perform a number of numerical simulations of typical galaxy mergers, computing the associated gravitational radiation waveforms as well as the energy released in the processes. Our simulations yield dimensionless gravitational wave amplitudes of the order of $10^{-13}$ and gravitational wave frequencies of the order of $10^{-16}$ Hz, when the galaxies are located at a distance of 10 Mpc. These values are of the same order as those arising in the gravitational radiation originated by strong variations of the gravitational field in the early Universe, and therefore, such gravitational waves cannot be directly observed by ground-based detectors. We discuss the feasibility of an indirect detection by means of the B-mode polarization of the Cosmic Microwave Background (CMB) induced by such waves. Our results show that the gravitational waves from encounters of dark matter galactic halos leave much too small an imprint on the CMB polarization to be actually observed with ongoing and future missions.Comment: 9 pages with revtex style, 3 ps figures; to be published in Physical Review

On the Use of Graphs for Node Connectivity in Wireless Sensor Networks for Hostile Environments

[EN] Wireless sensor networks (WSNs) have been extensively studied in the literature. However, in hostile environments where node connectivity is severely compromised, the system performance can be greatly affected. In this work, we consider such a hostile environment where sensor nodes cannot directly communicate to some neighboring nodes. Building on this, we propose a distributed data gathering scheme where data packets are stored in different nodes throughout the network instead to considering a single sink node. As such, if nodes are destroyed or damaged, some information can still be retrieved. To evaluate the performance of the system, we consider the properties of different graphs that describe the connections among nodes. It is shown that the degree distribution of the graph has an important impact on the performance of the system. A teletraffic analysis is developed to study the average buffer size and average packet delay. To this end, we propose a reference node approach, which entails an approximation for the mathematical modeling of these networks that effectively simplifies the analysis and approximates the overall performance of the system.The authors wish to thank the Consejo Nacional de Ciencia y Tecnologia (CONACyT), the Comision de Operacion y Fomento de Actividades Academicas, Instituto Politecnico Nacional (COFAA-IPN, project numbers 20196225 and 20196678), and the Estimulos al Desempeno de los Investigadores del Instituto Politecnico Nacional (EDI-IPN) for the support given for this work. The work of V. Pla was supported by Grant PGC2018-094151-B-I00 (MCIU/AEI/FEDER, UE).García-González, E.; Chimal-Eguía, JC.; Rivero-Angeles, ME.; Pla, V. (2019). On the Use of Graphs for Node Connectivity in Wireless Sensor Networks for Hostile Environments. Journal of Sensors. 2019:1-22. https://doi.org/10.1155/2019/7409329S1222019Eren, T. (2017). The effects of random geometric graph structure and clustering on localizability of sensor networks. International Journal of Distributed Sensor Networks, 13(12), 155014771774889. doi:10.1177/1550147717748898Clauset, A., Shalizi, C. R., & Newman, M. E. J. (2009). Power-Law Distributions in Empirical Data. SIAM Review, 51(4), 661-703. doi:10.1137/070710111Hakimi, S. L. (1962). On Realizability of a Set of Integers as Degrees of the Vertices of a Linear Graph. I. Journal of the Society for Industrial and Applied Mathematics, 10(3), 496-506. doi:10.1137/011003

NGC1600 - Cluster or Field Elliptical?

A study of the galaxy distribution in the field of the elliptical galaxy NGC1600 has been undertaken. Although this galaxy is often classified as a member of a loose group, all the neighbouring galaxies are much fainter and could be taken as satellites of NGC1600. The number density profile of galaxies in the field of this galaxy shows a decline with radius, with evidence of a background at approximately 1.3 Mpc. The density and number density profile are consistent with that found for other isolated early-type galaxies. NGC1600 appears as an extended source in X-rays, and the center of the X-ray emission seems not to coincide with the center of the galaxy. The velocity distribution of neighbouring galaxies has been measured from optical spectroscopic observations and shows that the mean radial velocity is approximately 85 km/s less than that of NGC1600, indicating that the centre of mass could lie outside the galaxy. The velocity dispersion of the `group' is estimated at 429 km/s. The inferred mass of the system is therefore of the order of 10^14 solar masses, a value that corresponds to a large group. NGC1600 therefore shares some similarities, but is not identical to, the `fossil clusters' detected in X-ray surveys. Implications of this result for studies of isolated early-type galaxies are briefly discussed.Comment: 8 pages, 5 figures and 2 table, accepted for publication in the Ap

Novel compatibilizers and plasticizers developed from epoxidized and maleinized chia oil in composites based on PLA and chia seed flour

[EN] Novel compatibilizers and plasticizers derived from epoxidized chia seed oil (ECO) and maleinized chia seed oil (MCO) have been applied in composites based on poly(lactic acid) (PLA) and 15 wt% chia seed flour (CSF). Results obtained have been compared to conventional silane coupling agent, (3-glycidyloxypropyl) trimethoxysilane (GPS), and a petroleum-based compatibilizer, poly(styrene-co-glycidyl methacrylate) copolymer (Xibond, (R)). The compatibilization effect of green composites were assessed by FTIR. The addition of all four compatibilizers improved the ductile mechanical and thermal properties of the composites. The morphology analysis revealed an improvement of interfacial adhesion of the CSF particles into the PLA matrix. In particular, ECO and MCO composites showed a roughness with long filaments in their morphology which plays a crucial role in improving the ductile properties highly. The elongation at break was 10 and 8 times higher using ECO and MCO, respectively, compared to uncompatibilized composite. Moreover, the composites manufactured showed low values (<9%) in the water uptake assay and a negligible compostability delay. The use of novel compatibilizers based on modified vegetable oils could mean an interesting proposal to obtain an entirely environmentally friendly composite with a remarkable ductile property.This research work was funded by the Ministry of Science and Innovation-¿Retos de la Sociedad¿. Project references: PID2020-119142RA-I00. I. Dominguez-Candela wants to thank Universitat Politècnica de València for his FPI grant (PAID-2019-SP20190013) and Generalitat Valenciana-GVA (ACIF/2020/233). J. Gomez-Caturla wants to thank Generalitat Valenciana-GVA, for his FPI grant (ACIF/2021/185) and grant FPU20/01732 funded by MCIN/AEI/10.13039/ 501100011033.Domínguez-Candela, I.; Gómez-Caturla, J.; Cardona, SC.; Lora-García, J.; Fombuena, V. (2022). Novel compatibilizers and plasticizers developed from epoxidized and maleinized chia oil in composites based on PLA and chia seed flour. European Polymer Journal. 173(111289):1-14. https://doi.org/10.1016/j.eurpolymj.2022.11128911417311128