A simple method to construct Flat Band lattices

We develop a simple and general method to construct arbitrary Flat Band lattices. We identify the basic ingredients behind zero-dispersion bands and develop a method to construct extended lattices based on a consecutive repetition of a given mini-array. The number of degenerated localized states is defined by the number of connected mini-arrays times the number of modes preserving the symmetry at a given connector site. In this way, we create one or more (depending on the lattice geometry) complete degenerated Flat Bands for quasi-one and two-dimensional systems. We probe our method by studying several examples, and discuss the effect of additional interactions like anisotropy or nonlinearity. At the end, we test our method by studying numerically a ribbon lattice using a continuous description.Comment: 11 pages, 11 figure

Las mujeres Mapuche como productoras agrícolas, 1930-1950

Este artículo examina el papel de la mujer Mapuche como productora agrícola en la economía familiar, mediante el acceso y manejo de capitales agrarios que se invierten en asociatividad con labradores varones, delineando la presencia de una pauta de acumulación de riqueza agropecuaria a nivel femenino paralela a la desplegada por los hombres. Variable que contribuirá al fortalecimiento de la economía familiar y el incremento de las explotaciones prediales en las reservas indígenas del período 1930-1950.Palabras claves: Agricultura Mapuche, economía Mapuche, Chile, historia agraria.AbstractThis article assesses the role played by Mapuche women as agricultural producers in the Mapuche’s family economy, through access and management of agrarian capital, which was invested in association with male farmers. It shows that female’s agricultural wealth accumulation followed a similar pattern to male’s agricultural wealth accumulation. This contributed to the strengthening of the family economy and to an increase in the exploitation of agricultural plots in the Mapuche’s reservations during the period 1930-1950.Keywords: Mapuche agriculture, Mapuche economy, Chile, agrarian history

Familia y vida cotidiana en poblados indígenas rurales. Cacicazgo de Codpa (1774-1820)

The colonial history of the family has been mainly written taking into consideration multi-ethnic urban villages, and downplaying the specific dynamics observed in rural indigenous populations. Based on marriage information from the doctrines of Belén and Codpa, I analyze the peculiarities of everyday life in the Indian villages of the chiefdom of Codpa as it relates to the cycle of life and the configuration of the family.La historia colonial de la familia se ha escrito preferentemente desde poblados urbanos pluriétnicos, restando importancia a las dinámicas particulares que se observan en las poblaciones indígenas rurales. Basándome en las informaciones matrimoniales de las doctrinas de Belén y Codpa, analizo las particularidades de la vida cotidiana que se desarrolla en los poblados indígenas del cacicazgo de Codpa, relacionadas con el ciclo vital y la conformación de la familia

Do different levels of fishing pressure, through spatial management, influence communities and ecological interactions in seagrass meadows in South Western Australia?

Marine Protected Areas (MPAs) are internationally recognised as a significant spatial management and cost-effective strategy to restore and conserve the marine ecosystems structure and function from human impact. MPAs have been declared with the aim to address a single or a set of management objectives in response to anthropogenic threats, such as fishing, which can have repercussions on biodiversity through indirect interactions or top-down control within an ecosystem or across ecosystems where consumers migrate to forage. However, this indirect impact of fishing remains poorly understood, and as a consequence, the effectiveness of MP As in conserving those ecological processes and broader biodiversity is also poorly understood. Therefore, this study investigated the potential effects of sanctuary zones (no-take MPAs) on higher-order consumers and their effects on benthic assemblage structure both on the reef and in adjacent seagrass meadows. Consumer assemblages were examined using underwater visual census (UVC) on reefs and seagrass meadows at a range of sites in sanctuary and fished zones in Marmion Marine Park (MMP) and Rottnest Island Marine Reserve (RIMP) over three seasons between July 2009 and March 2010. Epibenthic fauna and flora were also sampled using quadrats on reefs and at set distances away from reefs in adjacent Amphibolis seagrass meadows over the same period. Sanctuary zones had higher mean total abundance and biomass of fish compared to adjacent fished zones, and while not significant, there was also a trend of higher means rock lobsters abundance in sanctuary zones. However, there was a high degree of variability among sites nested in zone, and among seasons. Kingston Reefs sanctuary zone contained the highest rock lobster and fish abundance, biomass, and species richness across all seasons. In addition, there was a trend of decreasing mean abundance, biomass, and species richness of fish with increasing distance away from the reef in Amphibolis meadows. In terms of epibenthic fauna and flora assemblages, there was no significant difference in their abundances and taxa richness between zones, but as with consumers, there was high variability among sites within zone and among seasons. As sanctuary zones ii had substantially higher densities of consumers in close proximity to reefs than fished zones, it was expected that predation levels would be higher in sanctuary zones and would decrease with increasing distances away from the reef. However, there were no clear trends of decreasing epibenthic abundance and diversity with distance away from the reef. Furthermore, tethering experiments with gastropods, a major prey item for some consumer species, showed no significant differences in gastropod mortality between sites or with increasing distances away from the reef. Thus, a top-down effect caused by different abundances of consumers in sanctuary versus fished zones was not evident from the results. Much of the variability in higher-order consumers and epibenthic assemblage could be due to site-specific characteristics, including the age, size, and the geographical location of sanctuary zones, and the structural complexity of the habitat. The detection of consumers\u27 direct influence on prey abundance, richness, and distribution could be partly masked by their feeding habits, and the level of mobility of higher-order consumers. This study highlights the level of complexity of food web structures with consideration of other environmental and biological factors. It also provides important baseline of biological data on marine ecosystems in marine parks of southwest temperate waters of W A for future assessments of those marine parks. To meet a MPAs objective of biodiversity conservation, it is crucial for managers to acknowledge all natural variations in marine ecosystems, such as the life-history traits of individuals, when setting objectives for a MPAs performance, as protection may be suitable for some species and inadequate for others

La colonización minera y agrícola en la ciudad Imperial del Sur de Chile: 1551-1561

Study of the economic organization of the Imperial city district established since 1551 in southern Chile. We analyze the characteristics of the Spanish colonization around gold mining production, agricultural production of wheat, commercial traffic in connection with the port of Valdivia and the volume of the indigenous workforce, in the initial stage of the Spanish settlement in the region of rivers and Toltén Cautín.Estudio de la organización económica en el corregimiento de la ciudad Imperial establecida desde 1551 en el Sur de Chile. Se analizan las características de la colonización hispana en torno a la producción minera de oro, la producción agrícola de trigo, el tráfico mercantil en su conexión con el puerto de Valdivia y el volumen de la población laboral indígena, en la etapa inicial del asentamiento español en la comarca de los ríos Cautín y Toltén

Malas noticias para el Plan AUGE

Indexación: ScieloEn el reciente discurso del 21 de mayo, el Presidente Piñera ha ratificado su compromiso con subir a 80 los problemas de salud de los chilenos, que están cubiertos en las Garantías Explícitas de Salud (GES), mejor conocidas como AUGE, a partir de Julio de este año 2013. Sin embargo, lo que parece ser una muy buena noticia para el común de nuestros ciudadanos e inclusive para los médicos y profesionales de la salud de nuestro país, en realidad es más bien una pésima señal y muestra cómo los dos últimos gobiernos, independientemente de su color político, en realidad están matando el AUGE o GES, poniendo en jaque a una de las más exitosas políticas públicas de los últimos 23 años en nuestro país

The Effects of Vouchers on Academic Achievement: Evidence from Chile’s Conditional Voucher Program Juan A. Correa David Inostroza Francisco Parro Loreto Reyes Gabriel Ugarte Universidad Andrés Bello Marzo

Indexación: UNAB JEL Classi cation: H4; I2Abstract We use data from Chile's conditional voucher program to test the e ects of vouchers on academic achievement. Conditional vouchers have delivered extra resources to low-income, vulnerable students since 2008. Moreover, under this scheme, additional resources are contingent on the completion of speci c scholastic goals. Using a di erence-in-di erences approach, we nd a positive and signi cant e ect of vouchers on standardized test scores. Additionally, our results highlight the importance of conditioning the delivery of resources to some speci c academic goals when frictions exist in the education market

Quantum localized states in photonic flat-band lattices

The localization of light in flat-band lattices has been recently proposed and experimentally demonstrated in several configurations, assuming a classical description of light. Here, we study the problem of light localization in the quantum regime. We focus on quasi one-dimensional and two-dimensional lattices which exhibit a perfect flat-band inside their linear spectrum. Localized quantum states are constructed as eigenstates of the interaction Hamiltonian with a vanishing eigenvalue and a well defined total photon number. These are superpositions of Fock states with probability amplitudes given by positive as well as negative square roots of multinomial coefficients. The classical picture can be recovered by considering poissonian superpositions of localized quantum states with different total photon number. We also study the separability properties of flat band quantum states and apply them to the transmission of information via multi-core fibers, where these states allow for the total passive suppression of photon crosstalk and exhibit robustness against photon losses. At the end, we propose a novel on-chip setup for the experimental preparation of localized quantum states of light for any number of photons.Comment: 12 pages, 5 figure