Spin effects in strong-field laser-electron interactions

The electron spin degree of freedom can play a significant role in relativistic scattering processes involving intense laser fields. In this contribution we discuss the influence of the electron spin on (i) Kapitza-Dirac scattering in an x-ray laser field of high intensity, (ii) photo-induced electron-positron pair production in a strong laser wave and (iii) multiphoton electron-positron pair production on an atomic nucleus. We show that in all cases under consideration the electron spin can have a characteristic impact on the process properties and their total probabilities. To this end, spin-resolved calculations based on the Dirac equation in the presence of an intense laser field are performed. The predictions from Dirac theory are also compared with the corresponding results from the Klein-Gordon equation.Comment: 9 pages, 6 figure

Lifetimes of Confined Acoustic Phonons in Ultra-Thin Silicon Membranes

We study the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultra-thin free-standing silicon membranes. Using an ultrafast pump-probe technique of asynchronous optical sampling, we observe that the decay time of the first-order dilatational mode decreases significantly from \sim 4.7 ns to 5 ps with decreasing membrane thickness from \sim 194 to 8 nm. The experimental results are compared with theories considering both intrinsic phonon-phonon interactions and extrinsic surface roughness scattering including a wavelength-dependent specularity. Our results provide insight to understand some of the limits of nanomechanical resonators and thermal transport in nanostructures

Real-Time Context-Aware Microservice Architecture for Predictive Analytics and Smart Decision-Making

The impressive evolution of the Internet of Things and the great amount of data flowing through the systems provide us with an inspiring scenario for Big Data analytics and advantageous real-time context-aware predictions and smart decision-making. However, this requires a scalable system for constant streaming processing, also provided with the ability of decision-making and action taking based on the performed predictions. This paper aims at proposing a scalable architecture to provide real-time context-aware actions based on predictive streaming processing of data as an evolution of a previously provided event-driven service-oriented architecture which already permitted the context-aware detection and notification of relevant data. For this purpose, we have defined and implemented a microservice-based architecture which provides real-time context-aware actions based on predictive streaming processing of data. As a result, our architecture has been enhanced twofold: on the one hand, the architecture has been supplied with reliable predictions through the use of predictive analytics and complex event processing techniques, which permit the notification of relevant context-aware information ahead of time. On the other, it has been refactored towards a microservice architecture pattern, highly improving its maintenance and evolution. The architecture performance has been evaluated with an air quality case study

Population Relationship of Three Forestry Species, Aegiphila ferruginea, Oreopanax ecuadorensis, Vallea stipularis; in the Leonan de Llucud Forest, Chambo Canton, Chimborazo Province

The present investigation aims to relate the population of three native forest species of the Andean region of Ecuador: Oreopanax ecuadorensis Seem, Aegiphila ferruginea, and Vallea stipularis in the Leonan de Llucud high montane evergreen forest located in the Chambo canton. Through the inventory and observation of the distribution of these three species in three altitudinal floors, establishing ten plots within which circular subplots of five meters radius were placed, taking the species under study as the center, all individuals with diameter at breast height greater than or equal to 7 cm were selected. For each altitudinal floor, the Importance Value Index, the Simpson and Shannon-Weaver Biodiversity Indices, and the Sorensen Similarity Index were calculated. The results presented below are the result of the data obtained in the field and its interpretation. V. stipularis and O. ecuadorensis Seem show a close relationship, while A. ferruginea has a low population due to the exploitation it is subjected to in this forest, thus asserting the presence of this species in the red book at a near-threatened level. Keywords: evergreen forest, native forest species, altitudinal floors. Resumen La presente investigación pretende relacionar la población de tres especies forestales nativas de la región andina del Ecuador Oreopanax ecuadorensis Seem, Aegiphila ferruginea y Vallea stipularis en el bosque siempre verde montano alto Leonan de Llucud ubicado en el cantón Chambo; mediante la inventariación y observación de la distribución de estas tres especies en tres pisos altitudinales, estableciendo diez parcelas dentro de las cuales se colocaron subparcelas circulares de cinco metros de radio tomando como centro a las especies en estudio, se seleccionaron todos los individuos con Diámetro a la Altura del Pecho, mayor o igual a 7 cm. Para cada piso altitudinal se calculó el Índice de Valor de Importancia, los Índices de biodiversidad de Simpson y Shannon – Weaver y el Índice de similitud de Sorensen. Los resultados que a continuación presentamos son resultado de los datos obtenidos en campo y su interpretación. Teniendo que V. stipularis y O. ecuadorensis Seem presentan gran afinidad; en tanto que A. ferruginea presenta una baja poblacional debido a la explotación a la cual es sometida en este bosque, aseverándose así la presencia de esta especie en el libro rojo en nivel de casi amenazado. Palabras clave: bosque siempre verde, especies forestales nativas, pisos altitudinales

Viral metacommunities associated to bats and rodents at different spatial scales

One of the main goals of community ecology is to measure the relative importance of environmental filters to understand patterns of species distribution at different temporal and spatial scales. Likewise, the identification of factors that shape symbiont metacommunity structures is important in disease ecology because resulting structures drive disease transmission. We tested the hypothesis that distributions of virus species and viral families from rodents and bats are defined by shared responses to host phylogeny and host functional characteristics, shaping the viral metacommunity structures at four spatial scales (Continental, Biogeographical, Zoogeographical, and Regional). The contribution of host phylogeny and host traits to the metacommunity of viruses at each spatial scale was calculated using a redundant analysis of canonical ordering (RDA). For rodents, at American Continental scale the coherence of viral species metacommunity increased while the spatial scale decreased and Quasi-Clementsian structures were observed. This pattern suggests a restricted distribution of viruses through their hosts, while in the Big Mass (Europe, Africa, and Asia), the coherence decreased as spatial scale decreased. Viral species metacommunities associated with bats was dominated by random structures along all spatial scales. We suggest that this random pattern is a result of the presence of viruses with high occupancy range such as rabies (73%) and coronavirus (27%), that disrupt such structures. At viral family scale, viral metacommunities associated with bats showed coherent structures, with the emergence of Quasi- Clementsian and Checkerboard structures. RDA analysis indicates that the assemblage of viral diversity associated with rodents and bats responds to phylogenetic and functional characteristics, which alternate between spatial scales. Several of these variations could be subject to the spatial scale, in spite of this, we could identify patterns at macro ecological scale. The application of metacommunity theory at symbiont scales is particularly useful for large-scale ecological analysis. Understanding the rules of host-virus association can be useful to take better decisions in epidemiological surveillance, control and even predictions of viral distribution and dissemination