Effective Dielectric Response of Metamaterials

We use a homogenization procedure for Maxwell's equations in order to obtain in the local limit the frequency ($\omega$) dependent macroscopic dielectric response $\epsilon^M(\omega)$ of metamaterials made of natural constituents with any geometrical shape repeated periodically with any structure. We illustrate the formalism calculating $\epsilon^M(\omega)$ for several structures. For dielectric rectangular inclusions within a conducting material we obtained a very anisotropic response which changes along one direction from conductor-like at low $\omega$ to a resonant dielectric-like at large $\omega$, attaining a very small reflectance at intermediate frequencies unrelated to surface plasmon excitation and which can be tuned through geometrycal tayloring. A similar behavior is obtained for other shapes close to the percolation threshold.Comment: 16 pages 7 figures. Accepted in Phys. Rev. B (2009-06-08

Distribución temporal del tamaño de los molariformes de Ursus spelaeus Ros.-Hein.ibérico

[Abstract] This paper deals with a metrical comparison of cheek-teeth length of Ursus spelaeus Ros.-Hein.Iberian population representatives

Dinámicas socioecológicas y ecoturismo comunitario: Un análisis comparativo en el eje fluvial Guayabero-Guaviare

The effects of the ecotourism in the relationships between inhabitants and their environment are complex and multidimensional. To explore these effects, two community ecotourism initiatives in the Guaviare Province were comparatively analyzed. This territory has been historically affected by the armed conflict and today is given priority as a scenery for the peace construction. The analysis herein articulates approaches both from the political ecology and the socio-ecological systems and considers how important it is to understand the power relations emerging in community ecotourism contexts that, in turn, help to measure how this kind of tourism impacts the socio-ecological dynamics and the strategies by the peasant families who try to diversify their economies to made them sustainable. © 2018, Pontificia Universidad Javeriana. All rights reserved

Exploring pig trade patterns to inform the design of risk-based disease surveillance and control strategies

An understanding of the patterns of animal contact networks provides essential information for the design of risk-based animal disease surveillance and control strategies. This study characterises pig movements throughout England and Wales between 2009 and 2013 with a view to characterising spatial and temporal patterns, network topology and trade communities. Data were extracted from the Animal and Plant Health Agency (APHA)’s RADAR (Rapid Analysis and Detection of Animal-related Risks) database, and analysed using descriptive and network approaches. A total of 61,937,855 pigs were moved through 872,493 movements of batches in England and Wales during the 5-year study period. Results show that the network exhibited scale-free and small-world topologies, indicating the potential for diseases to quickly spread within the pig industry. The findings also provide suggestions for how risk-based surveillance strategies could be optimised in the country by taking account of highly connected holdings, geographical regions and time periods with the greatest number of movements and pigs moved, as these are likely to be at higher risk for disease introduction. This study is also the first attempt to identify trade communities in the country, information which could be used to facilitate the pig trade and maintain disease-free status across the country in the event of an outbreak

Improving ANAIS-112 sensitivity to DAMA/LIBRA signal with machine learning techniques

Abstract The DAMA/LIBRA observation of an annual modulation in the detection rate compatible with that expected for dark matter particles from the galactic halo has accumulated evidence for more than twenty years. It is the only hint of a direct detection of the elusive dark matter, but it is in strong tension with the negative results of other very sensitive experiments, requiring ad-hoc scenarios to reconcile all the present experimental results. Testing the DAMA/LIBRA result using the same target material, NaI(Tl), removes the dependence on the particle and halo models and is the goal of the ANAIS-112 experiment, taking data at the Canfranc Underground Laboratory in Spain since August 2017 with 112.5 kg of NaI(Tl). At very low energies, the detection rate is dominated by non-bulk scintillation events and careful event selection is mandatory. This article summarizes the efforts devoted to better characterize and filter this contribution in ANAIS-112 data using a boosted decision tree (BDT), trained for this goal with high efficiency. We report on the selection of the training populations, the procedure to determine the optimal cut on the BDT parameter, the estimate of the efficiencies for the selection of bulk scintillation in the region of interest (ROI), and the evaluation of the performance of this analysis with respect to the previous filtering. The improvement achieved in background rejection in the ROI, but moreover, the increase in detection efficiency, push the ANAIS-112 sensitivity to test the DAMA/LIBRA annual modulation result beyond 3σ with three-year exposure, being possible to reach 5σ by extending the data taking for a few more years than the scheduled 5 years which were due in August 2022

Interacciones en el manejo forestal y las prácticas agrícolas en comunidades originarias del Estado de México, México: el modelo de paisajes bioculturales a escala local: Interactions in forest management and agricultural practices in communities originating from the State of Mexico, Mexico: the biocultural landscape model at a local scale

La implementación del modelo de paisajes bioculturales a escala local en los pueblos originarios de México podría conducir a la resignificación de dichos paisajes bioculturales, ya que permite la integración de prácticas y saberes para su gestión sostenible. El objetivo de este estudio fue identificar las dimensiones que caracterizan a los aspectos de los paisajes bioculturales, así como las interacciones en el manejo forestal y las prácticas agrícolas en comunidades originarias del Estado de México, México, para relacionarlas con los objetivos a escala local del modelo de paisajes bioculturales. Con un enfoque cualitativo, se realizó un taller participativo dirigido a miembros de Organizaciones No Gubernamentales (ONG) y académicos especialistas en el tema, que constó de dos etapas. En la primera etapa, por equipos de trabajo, se identificó las dimensiones que caracterizan a los aspectos de los paisajes bioculturales de comunidades originarias, así como las tres dimensiones más importantes de cada aspecto; en la segunda etapa, de manera grupal, se identificaron las interacciones bosque-agricultura, bosque y agricultura, así como su relación con los objetivos locales de la implementación del modelo de paisajes bioculturales. Concluyendo que la identificación de las interacciones en el manejo forestal y las prácticas agrícolas en comunidades originarias podría facilitar el diseño e implementación de los diferentes objetivos a escala local de dicho modelo. The implementation of the biocultural landscapes model at a local scale in the indigenous peoples of Mexico could lead to the resignification of said biocultural landscapes, since it allows the integration of practices and knowledge for their sustainable management. The objective of this study was to identify the dimensions that characterize the aspects of biocultural landscapes, as well as the interactions in forest management and agricultural practices in communities originating from the State of Mexico, Mexico, to relate them to the local-scale objectives of the biocultural landscape model. With a qualitative approach, a participatory workshop was held aimed at members of Non-Governmental Organizations (NGOs) and academics specializing in the topic, which consisted of two stages. In the first stage, by work teams, the dimensions that characterize the aspects of the biocultural landscapes of native communities were identified, as well as the three most important dimensions of each aspect; In the second stage, in a group manner, the forest-agriculture, forest and agriculture interactions were identified, as well as their relationship with the local objectives of the implementation of the biocultural landscape model. Concluding that the identification of interactions in forest management and agricultural practices in native communities could facilitate the design and implementation of the different objectives at the local scale of said model

Tectonic denudation and topographic development in the Spanish Sierra Nevada

The denudation history of the rapidly uplifting western part of the Spanish Sierra Nevada was assessed using apatite fission track (AFT) ages and 10Be analyses of bedrock and fluvial sediments. Major contrasts in the denudation history are recorded within the 27 km2 Río Torrente catchment. Upland areas are characterized by low-relief, low slope angles, and locally the preservation of shallow marine sediments, which have experienced <200 m of erosion in the last 9 Myr. However, AFT age determinations from samples collected close to the marine sediments imply >2 km of denudation since circa 4 Ma. The minimum denudation rates of 0.4 mm yr−1 derived from AFT also contrast with the slow medium-term (104 years) erosion rates (0.044 ± 0.015 mm yr−1) estimated from 10Be measurements at high elevations. The local medium-long-term contrasts in denudation rates within the high Sierra Nevada indicate that much of the unroofing occurs by tectonic denudation on flat-lying detachments. In lower elevation parts of the catchment, rapid river incision coupled to rock uplift has produced ∼1.6 km of relief, implying that the rivers and adjacent hillslopes close to the edge of the orogen are sensitive to normal-fault-driven changes in base level. However, these changes are not transmitted into the low-relief slowly eroding upland areas. Thus the core of the mountain range continues to increase in elevation until the limits of crustal strength are reached and denudation is initiated along planes of structural weakness. We propose that this form of tectonic denudation provides an effective limit to relief in young orogens

Improving ANAIS-112 sensitivity to DAMA/LIBRA signal with machine learning techniques

The DAMA/LIBRA observation of an annual modulation in the detection rate compatible with that expected for dark matter particles from the galactic halo has accumulated evidence for more than twenty years. It is the only hint of a direct detection of the elusive dark matter, but it is in strong tension with the negative results of other very sensitive experiments, requiring ad-hoc scenarios to reconcile all the present experimental results. Testing the DAMA/LIBRA result using the same target material, NaI(Tl), removes the dependence on the particle and halo models and is the goal of the ANAIS-112 experiment, taking data at the Canfranc Underground Laboratory in Spain since August 2017 with 112.5 kg of NaI(Tl). At very low energies, the detection rate is dominated by non-bulk scintillation events and careful event selection is mandatory. This article summarizes the efforts devoted to better characterize and filter this contribution in ANAIS-112 data using a boosted decision tree (BDT), trained for this goal with high efficiency. We report on the selection of the training populations, the procedure to determine the optimal cut on the BDT parameter, the estimate of the efficiencies for the selection of bulk scintillation in the region of interest (ROI), and the evaluation of the performance of this analysis with respect to the previous filtering. The improvement achieved in background rejection in the ROI, but moreover, the increase in detection efficiency, push the ANAIS-112 sensitivity to test the DAMA/LIBRA annual modulation result around 3$\sigma$ with three-year exposure, being possible to reach 5$\sigma$ by extending the data taking for a few more years than the scheduled 5 years which were due in August 2022

La cueva de el Sidron (Borines, Piloña, Asturias) : primeros resultados

Se exponen los resultados preliminares de las excavaciones arqueológicas llevadas a cabo en la Cueva de El Sidrón entre 2000 y 2002, de acuerdo con los tres objetivos principales que conciernen al registro fósil humano: las características antropológicas, cómo y cuándo llegaron allí y la relación entre fósiles y cultura. Las primeras conclusiones obtenidas son que los restos humanos pertenecen al Neandertal, que el registro arqueológico corresponde a un tecno-complejo del Paleolítico Medio y que están en posición secundaria.We expose the preliminary results ofthe archaeological excavations developed between 2000-2002 in Sidrón's Cave, according to the three main objectives that concern the human fossil record: the anthropological characteristics, how and when they arrived there and the relation between fossils and culture. We conclude preliminarily that the record belongs to Horno Neanderthalensis, archeological remains to the Middle Paleolithic techno-complex, and they are in a secondary [email protected]