Primordial black hole production during preheating in a chaotic inflationary model

In this paper we review the production of primordial black holes (PBHs) during preheating after a chaotic inflationary model. All relevant equations of motion are solved numerically in a modified version of HLattice, and we then calculate the mass variance to determine structure formation during preheating. It is found that production of PBHs can be a generic result of the model, even though the results seem to be sensitive to the values of the smoothing scale. We consider a constraint for overproduction of PBHs that could uncover some stress between inflation-preheating models and observations.Comment: 6 pages, 5 figures. Prepared for the conference proceedings of the 9th Mexican School on Gravitation and Mathematical Physics : Cosmology for the XXI Century: Inflation, Dark Matter and Dark Energ

A limnological study of Lake Patzcuaro, Mexico with a consideration of the applicability of remote sensing techniques

This thesis presents the results of a hydrobiological study with implications for lake management obtained during six months of field work in Lake Patzcuaro, Michoacan, Mexico. The conventional data are coupled with surveys made with multispectral satellite imagery. Lake Patzcuaro, Michoacan, Mexico is a tropical high altitude freshwater lake located in the southern edge of the Mexican plateau. The lake originated from tecto-volcanic processes associated with the Eje Neovolcanico Transversal during the late Tertiary and Quaternary periods. Data for 25 morphometrical parameters describing the geomorphology of Lake Patzcuaro were derived from an up-to- date bathymetric survey with contour lines at 1.0 m intervals: Maximum depths were observed in the northern part of the lake whereas considerable shallow areas are developing in the south: insulosity is continuously modified due to certain areas becoming part of the mainland and the appearance of new islands with increasing shallowness and man-made channels. The lake is an endorheic basin and the annual water balance is primarily controlled by differences between rainfall and evaporation. Since annual evaporation is higher than rainfall, it is considered that net water inputs to the lake come as seepage from the drainage area. However, by using a simple mass balance simulation model it is illustrated that the contribution of seepage is being reduced due to the continuous deterioration of the catchment area. The lake is well mixed and high oxygen levels are always present from surface to bottom. The lake is alkaline- carbonate with moderate levels of hardness and high concentrations of total phosphorus, chlorophyll-a and suspended solids. By comparing three conventional trophic state indices and input-output phosphorus models, Lake Patzcuaro is considered to be mostly eutrophic with some isolated mesotrophic and, oligo-mesotrophic areas. High turbidities are observed possibly due to volcanic silt, raw sewage and increasing erosion loads. It is considered that Lake Patzcuaro is principally 1ight-1imited due to scattering and attenuation effects from inorganic materials. A predictive model of water quality variables has been developed for SPOT-1 multispectral imagery, and applied.to Lake Patzcuaro. By using canonical and principal component analysis it is shown that, at most, two water quality variables, chlorophyll-a and suspended solids concentration, can be derived from the SPOT data. Having established the independent predictiviness of a set of empirical relations between the SPOT data and the water quality parameters, the whole lake was analysed to reveal the spatial distribution of chlorophyll-a and suspended solids. It is revealed that a very dense algal bloom had occured during the period of study. No bloom of such intensity has ever been observed before in Lake Patzcuaro. The applicability of SPOT imagery to water quality monitoring is clearly demonstrated. The cost-effectiveness of remote sensing techniques for water quality mapping and lake management is discussed using the Lake Patzcuaro as an example

Aprendizaje y Construcción de Capacidades Tecnológicas

The aim of this article is to provide an overview of the literature on learning and the building of technological capabilities processes at the firm’s level in both, developing and developed countries. It also briefly reviews some works dealing with these issues at the level of sectors and countries. After analyzing the strengths and weaknesses of the existing approaches, the paper attempts to identify the research themes that seem to be emerging (such as new indicators of technological capabilities, building capabilities in the services sector and learning networks) and advances some ideas about the areas that require further research to be done.El objetivo de ese artículo es revisar la literatura y proporcionar una visión general acerca del aprendizaje y construcción de las capacidades tecnológicas dentro de las empresas en países desarrollados y en vías de desarrollo. También repasa algunos trabajos que se ocupan de algunos sectores y países. Después de revisar las fortalezas y debilidades se identifican algunos temas de investigación que parecen ser emergentes (como por ejemplo los indicadores de capacidades tecnológicas, del sector de servicios, aprendizaje de redes) y algunas ideas acerca de aquellos sectores que requieren una investigación adicional.The aim of this article is to provide an overview of the literature on learning and the building of technological capabilities processes at the firm’s level in both, developing and developed countries. It also briefly reviews some works dealing with these issues at the level of sectors and countries. After analyzing the strengths and weaknesses of the existing approaches, the paper attempts to identify the research themes that seem to be emerging (such as new indicators of technological capabilities, building capabilities in the services sector and learning networks) and advances some ideas about the areas that require further research to be done

Una historia del campo: Fosca memoria e historia 1940-1970

A través del relato de la abuela Tulia emprenderemos un viaje a Fosca, un pueblo ubicado en una zona montañosa en el oriente de Cundinamarca, este lugar conserva su tradición campesina y alberga la memoria de un sinnúmero de historias de las gentes del campo. La historia de vida de la abuela, junto a otros relatos, nos enseñaran aspectos relevantes de la vida campesina hace 50 años.By telling the story of grandma, we are oing to take to Fosca, a litter village located in a mountainnous región at the Eastern part of Cundinamarca, Colombia. This place preserves its rural traditions and keeps the memory within countless tales about other coutry people. Along with other stories, the granma s life story will show us the main aspects of rural life 50 years ago.Historiador (a)Pregrad

Variation in yellowfin tuna (Thunnus albacares) catches related to El Niño-Southern Oscillation events at the entrance to the Gulf of California

Fishery catch data on yellowfin tuna (Thunnus albacares) were examined to study the effects of El Niño events between 1990 and 1999 for an area in the northeastern tropical Pacific (18−24°N, 112−104°W). The data were extracted from a database of logbook records from the Mexican tuna purse-seine f leet. Latitudinal distribution of the catches increased from south to north for the 10-year period. Highest catches and effort were concentrated between 22°N and 23°N. This area accumulated 48% of the total catch over the 10year period. It was strongly correlated with El Niño-Southern Oscillation (ENSO) events. At least two periods of exceptionally high catches occurred following El Niño events in 1991 and 1997. Peaks of catches were triggered by the arrival of positive anomalies of sea surface temperature (SST) to the area. A delay of two to four months was observed between the occurrence of maximum SST anomalies at the equator and peaks of catch. Prior to these two events, negative SST anomalies were the dominant feature in the study area and catch was extremely low. This trend of negative SST anomalies with low catches followed by positive SST anomalies and high catches may be attributed to northward yellowfin tuna migration patterns driven by El Niño forcing, a result that contrasts with the known behavior of decreasing relative abundance of these tuna after El Niño events in the eastern Pacific. However, this decrease in relative abundance may be the result of a local or subregional effect

Range-only SLAM schemes exploiting robot-sensor network cooperation

Simultaneous localization and mapping (SLAM) is a key problem in robotics. A robot with no previous knowledge of the environment builds a map of this environment and localizes itself in that map. Range-only SLAM is a particularization of the SLAM problem which only uses the information provided by range sensors. This PhD Thesis describes the design, integration, evaluation and validation of a set of schemes for accurate and e_cient range-only simultaneous localization and mapping exploiting the cooperation between robots and sensor networks. This PhD Thesis proposes a general architecture for range-only simultaneous localization and mapping (RO-SLAM) with cooperation between robots and sensor networks. The adopted architecture has two main characteristics. First, it exploits the sensing, computational and communication capabilities of sensor network nodes. Both, the robot and the beacons actively participate in the execution of the RO-SLAM _lter. Second, it integrates not only robot-beacon measurements but also range measurements between two di_erent beacons, the so-called inter-beacon measurements. Most reported RO-SLAM methods are executed in a centralized manner in the robot. In these methods all tasks in RO-SLAM are executed in the robot, including measurement gathering, integration of measurements in RO-SLAM and the Prediction stage. These fully centralized RO-SLAM methods require high computational burden in the robot and have very poor scalability. This PhD Thesis proposes three di_erent schemes that works under the aforementioned architecture. These schemes exploit the advantages of cooperation between robots and sensor networks and intend to minimize the drawbacks of this cooperation. The _rst scheme proposed in this PhD Thesis is a RO-SLAM scheme with dynamically con_gurable measurement gathering. Integrating inter-beacon measurements in RO-SLAM signi_cantly improves map estimation but involves high consumption of resources, such as the energy required to gather and transmit measurements, the bandwidth required by the measurement collection protocol and the computational burden necessary to integrate the larger number of measurements. The objective of this scheme is to reduce the increment in resource consumption resulting from the integration of inter-beacon measurements by adopting a centralized mechanism running in the robot that adapts measurement gathering. The second scheme of this PhD Thesis consists in a distributed RO-SLAM scheme based on the Sparse Extended Information Filter (SEIF). This scheme reduces the increment in resource consumption resulting from the integration of inter-beacon measurements by adopting a distributed SLAM _lter in which each beacon is responsible for gathering its measurements to the robot and to other beacons and computing the SLAM Update stage in order to integrate its measurements in SLAM. Moreover, it inherits the scalability of the SEIF. The third scheme of this PhD Thesis is a resource-constrained RO-SLAM scheme based on the distributed SEIF previously presented. This scheme includes the two mechanisms developed in the previous contributions {measurement gathering control and distribution of RO-SLAM Update stage between beacons{ in order to reduce the increment in resource consumption resulting from the integration of inter-beacon measurements. This scheme exploits robot-beacon cooperation to improve SLAM accuracy and e_ciency while meeting a given resource consumption bound. The resource consumption bound is expressed in terms of the maximum number of measurements that can be integrated in SLAM per iteration. The sensing channel capacity used, the beacon energy consumed or the computational capacity employed, among others, are proportional to the number of measurements that are gathered and integrated in SLAM. The performance of the proposed schemes have been analyzed and compared with each other and with existing works. The proposed schemes are validated in real experiments with aerial robots. This PhD Thesis proves that the cooperation between robots and sensor networks provides many advantages to solve the RO-SLAM problem. Resource consumption is an important constraint in sensor networks. The proposed architecture allows the exploitation of the cooperation advantages. On the other hand, the proposed schemes give solutions to the resource limitation without degrading performance

‘Yes-in-my-backyard’: Spatial differences in the valuation of forest services and local co-benefits for carbon markets in México

Forests provide many and large benefits, including cost-efficient climate change mitigation. However international carbon markets have not stimulated the demand for forestry offsets. Domestic market-mechanisms are emerging inmany countries and forests could be highly valued through these policies asmost of the benefits produced by forests are enjoyed locally. Here, a choice experiment explores drivers of valuation and willingness to pay for forest carbon services in voluntary markets in Mexico by comparing the valuation of citizens from four regions to test geographical preference for projects (n = 645). Findings from multinomial-logit models show valuation of forest carbon services is transferable and citizens would pay more for offsets from projects closer to their homes. Proximate forests provide a range of co-benefits to local users, including environmental services and opportunities for recreation. Factors related to valuation include sense of responsibility, previous knowledge of carbon emissions, previous visits to the sites, regional identification and the valuation of local environmental services (e.g. improvements in local air quality). Knowledge of spatial heterogeneity in valuation of the use of forest services can help to design market-based instruments by identifying highly valued areas for environmental services programs and carbon markets