Entanglement and alpha entropies for a massive scalar field in two dimensions

We find the analytic expression of the trace of powers of the reduced density matrix on an interval of length L, for a massive boson field in 1+1 dimensions. This is given exactly (except for a non universal factor) in terms of a finite sum of solutions of non linear differential equations of the Painlev\'e V type. Our method is a generalization of one introduced by Myers and is based on the explicit calculation of quantities related to the Green function on a plane, where boundary conditions are imposed on a finite cut. It is shown that the associated partition function is related to correlators of exponential operators in the Sine-Gordon model in agreement with a result by Delfino et al. We also compute the short and long distance leading terms of the entanglement entropy. We find that the bosonic entropic c-function interpolates between the Dirac and Majorana fermion ones given in a previous paper. Finally, we study some universal terms for the entanglement entropy in arbitrary dimensions which, in the case of free fields, can be expressed in terms of the two dimensional entropy functions.Comment: 13 pages, 2 figure

Tropical Grass Growth Functions Modeling by Using Nonlinear Mixed Models

Nonlinear Growth curves are used for modeling plant physiological variables. These models are preferable because the polynomial coefficients of the equations have a biological significance. The response variables of the curves occurs commonly with repeated measurements over time and measurements are on different environments. The traditional statistical analysis does not include a repeated measures approach, which can lead to improper estimation of the error terms. It is important to study the growth of tropical grass (Da Silva and Carvalho 2005)

Predicting distributions of known and unknown reptile species in Madagascar

Despite the importance of tropical biodiversity(1), informative species distributional data are seldom available for biogeographical study or setting conservation priorities(2,3). Modelling ecological niche distributions of species offers a potential soluion(4-7); however, the utility of old locality data from museums, and of more recent remotely sensed satellite data, remains poorly explored, especially for rapidly changing tropical landscapes. Using 29 modern data sets of environmental land coverage and 621 chameleon occurrence localities from Madagascar ( historical and recent), here we demonstrate a significant ability of our niche models in predicting species distribution. At 11 recently inventoried sites, highest predictive success (85.1%) was obtained for models based only on modern occurrence data (74.7% and 82.8% predictive success, respectively, for pre-1978 and all data combined). Notably, these models also identified three intersecting areas of over-prediction that recently yielded seven chameleon species new to science. We conclude that ecological niche modelling using recent locality records and readily available environmental coverage data provides informative biogeographical data for poorly known tropical landscapes, and offers innovative potential for the discovery of unknown distributional areas and unknown species.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62843/1/nature02205.pd

Predicting Distribution of Aedes Aegypti and Culex Pipiens Complex, Potential Vectors of Rift Valley Fever Virus in Relation to Disease Epidemics in East Africa.

The East African region has experienced several Rift Valley fever (RVF) outbreaks since the 1930s. The objective of this study was to identify distributions of potential disease vectors in relation to disease epidemics. Understanding disease vector potential distributions is a major concern for disease transmission dynamics. DIVERSE ECOLOGICAL NICHE MODELLING TECHNIQUES HAVE BEEN DEVELOPED FOR THIS PURPOSE: we present a maximum entropy (Maxent) approach for estimating distributions of potential RVF vectors in un-sampled areas in East Africa. We modelled the distribution of two species of mosquitoes (Aedes aegypti and Culex pipiens complex) responsible for potential maintenance and amplification of the virus, respectively. Predicted distributions of environmentally suitable areas in East Africa were based on the presence-only occurrence data derived from our entomological study in Ngorongoro District in northern Tanzania. Our model predicted potential suitable areas with high success rates of 90.9% for A. aegypti and 91.6% for C. pipiens complex. Model performance was statistically significantly better than random for both species. Most suitable sites for the two vectors were predicted in central and northwestern Tanzania with previous disease epidemics. Other important risk areas include western Lake Victoria, northern parts of Lake Malawi, and the Rift Valley region of Kenya. Findings from this study show distributions of vectors had biological and epidemiological significance in relation to disease outbreak hotspots, and hence provide guidance for the selection of sampling areas for RVF vectors during inter-epidemic periods

Analysis of the growth of Chetumal grass established in a tropical climate

Objective: To evaluate the growth of Chetumal grass (Urochloa humidicola CIAT 679), in order to determine the optimal moment for the first harvest. Design/Methodology/Approach: A completely randomized experimental block design, with measurements repeated over time, and three repetitions was used. Morphological composition (MC), growth rate (GR), plant height (PH), intercepted radiation (IR), leaf:stem ratio (L:S), leaf:no-leaf ratio (L:NL), and aerial biomass (AB) —as well as leaf biomass (LB), stem biomass (SB), dead material (DM), net growth (NG), and total biomass (TB)— were evaluated every fifteen days, except for the two first samplings, which were carried out on a monthly basis. Data were analyzed using the GLM procedure of the SAS software and Tukey’s mean comparison test (α£0.05). Results: The morphological composition (MC) of the Chetumal grass was statistically different (p<0.05), during the different growth ages. The maximum accumulation of total biomass (TB) (13,324 kg DM ha-1), leaf biomass (LB) (2,569 kg DM ha-1), and growth rate (GR) (99 kg DM ha-1 d-1) was reached at 135 DAS. On that day, the prairie reached a 68 cm plant height (PH) and 100% intercepted radiation (IR). The L:S ratio decreased from 1.62 to 0.31, while L:NL ratio changed from 1.62 to 0.22. Study Limitations/Implications: The Brachiaria humidicola cv. Chetumal grass reached its highest potential during the rainy season. Findings/Conclusions: The first cut of the Urochloa humidicola cv. Chetumal grass can be carried out at 135 DAS, when the highest accumulation of total biomass (TB), leaf biomass (LB), and growth rate (GR) is recorded

Análisis de crecimiento del pasto Toledo Urochloa brizantha (Hochst. ex A. Rich.) R.D. Webster en clima cálido subhúmedo

Objective: Perform a growth analysis of Toledo grass (Urochloa brizantha CIAT 26110) during de rainy season, from sowing to 180 days, to determine the optimum harvesting moment. Design/methodology/approach: The morphological composition (CM), growth rate (GR), plant height, intercepted radiation (RI), leaf / stem ratio (L:S), leaf / non-leaf (L:NL), and biomass accumulation were evaluated every fifteen days during a 180 days period, except for the first two samples (monthly). Data were analyzed using the GLM procedure of SAS, under an experimental design of randomized blocks, with repeated measures over time, with three replicates.  Results: The CM varied significantly (P<0.01) through the different physiological states. The maximum production of aerial biomass (19.9 t DM ha-1) and GR (131.9 kg DM ha-1 day-1) were reached 150 days after sowing (dap) and that of leaves (3.9 t DM ha-1) was at 135 dap. At this time the RI was 100% and the height of plant was 106 cm. Limitations on study/implications: Toledo grass should be planted in the rainy season to be used when the canopy reaches a coverage greater than 80%, because the proportion of leaves decreases as the age of the plant progresses. Findings/conclusions: The highest accumulated total biomass, so it is suggested that the cut be made at 135 days after plantingObjetivo: realizar un análisis de crecimiento del pasto Toledo (Urochloa brizantha CIAT 26110) en la época de lluvias, desde la siembra hasta los 180 días, para determinar el momento óptimo de cosecha. Diseño/metodología/aproximación: Se evaluó la composición morfológica (CM), tasa de crecimiento (TC), altura de planta, radiación interceptada (RI), relación hoja/tallo (H:T), hoja/no hoja (H:NH) y la acumulación de biomasa aérea, a intervalos de quince días, a excepción de los dos primeros muestreos que fueron mensuales. Los datos fueron analizados mediante el procedimiento GLM de SAS, bajo un diseño experimental de bloques al azar, con medidas repetidas en el tiempo, con tres repeticiones. Resultados: La CM varió (P£0.01) a través de los diferentes estados fisiológicos. La máxima producción de biomasa aérea (19.9 t MS ha-1) y TC (131.9 kg MS ha-1 día-1) se alcanzó a los 150 días después de la siembra (dds), y la de hojas (3.9 t MS ha-1) fue a los 135 dds, en este momento la RI fue del 100% y la altura de 106 cm. Limitaciones del estudio/implicaciones: El pasto Toledo debe ser sembrado a inicio de la época de lluvias para ser usado cuando la cobertura del suelo sea mayor a 80 %, debido a que la proporción de hojas decrece conforme avanza la edad de la planta. Hallazgos/conclusiones: La máxima TC coincidió con la mayor biomasa total acumulada a los 135 (dds), por lo que se sugiere realizar el corte en este momento

Spatial heterogeneity of habitat suitability for Rift Valley fever occurrence in Tanzania: an ecological niche modelling approach

Despite the long history of Rift Valley fever (RVF) in Tanzania, extent of its suitable habitat in the country remains unclear. In this study we investigated potential effects of temperature, precipitation, elevation, soil type, livestock density, rainfall pattern, proximity to wild animals, protected areas and forest on the habitat suitability for RVF occurrence in Tanzania. Presence-only records of 193 RVF outbreak locations from 1930 to 2007 together with potential predictor variables were used to model and map the suitable habitats for RVF occurrence using ecological niche modelling. Ground-truthing of the model outputs was conducted by comparing the levels of RVF virus specific antibodies in cattle, sheep and goats sampled from locations in Tanzania that presented different predicted habitat suitability values. Habitat suitability values for RVF occurrence were higher in the northern and central-eastern regions of Tanzania than the rest of the regions in the country. Soil type and precipitation of the wettest quarter contributed equally to habitat suitability (32.4% each), followed by livestock density (25.9%) and rainfall pattern (9.3%). Ground-truthing of model outputs revealed that the odds of an animal being seropositive for RVFV when sampled from areas predicted to be most suitable for RVF occurrence were twice the odds of an animal sampled from areas least suitable for RVF occurrence (95% CI: 1.43, 2.76, p < 0.001). The regions in the northern and central-eastern Tanzania were more suitable for RVF occurrence than the rest of the regions in the country. The modelled suitable habitat is characterised by impermeable soils, moderate precipitation in the wettest quarter, high livestock density and a bimodal rainfall pattern. The findings of this study should provide guidance for the design of appropriate RVF surveillance, prevention and control strategies which target areas with these characteristics

Campaña de sensibilización para el proyecto Ciudad Amigable con los mayores en Guadalajara, Jalisco: Equipo de producción

El presente reporte se enfoca en la creación de materiales audiovisuales para transformar la percepción actual de las y los adultos mayores, esto a partir de un eje rector que fue la diversidad en las formas de envejecer. El objetivo fue crear una campaña de sensibilización a partir de contenidos que se habían hecho en periodos anteriores del PAP, y con estos, mostrar una imagen digna de las y los adultos mayores para generar una transformación de los estereotipos que giran en torno a ellos. El trabajo se realizó a partir de un diagnóstico para conocer las formas en que se estaban siendo representados los adultos mayores en distintos medios de comunicación; y a partir de ahí se identificaron los recursos y elementos que ayudaban a generar una imagen digna e íntegra de ellos y los que no para usar como referencia de lo que se debía hacer y lo que no. Dentro de los resultados, encontramos distintos productos audiovisuales y gráficos que forman parte de una campaña de sensibilización y en los que se construye una imagen digna de los adultos mayores teniendo en cuenta las distintas formas de envejecer.ITESO, A.C

Ecology and Geography of Plague Transmission Areas in Northeastern Brazil

Plague in Brazil is poorly known and now rarely seen, so studies of its ecology are difficult. We used ecological niche models of historical (1966-present) records of human plague cases across northeastern Brazil to assess hypotheses regarding environmental correlates of plague occurrences across the region. Results indicate that the apparently focal distribution of plague in northeastern Brazil is indeed discontinuous, and that the causes of the discontinuity are not necessarily only related to elevation—rather, a diversity of environmental dimensions correlate to presence of plague foci in the region. Perhaps most interesting is that suitable areas for plague show marked seasonal variation in photosynthetic mass, with peaks in April and May, suggesting links to particular land cover types. Next steps in this line of research will require more detailed and specific examination of reservoir ecology and natural history