Análisis de los efectos de intervenciones públicas en la recuperación de centros urbanos : caso de estudio barrio las Cruces, Bogotá 2002-2014

En el presente estudio de caso se hace un análisis de los principales efectos socio-espaciales y económicos que tuvieron intervenciones públicas dirigidas a recuperar el centro de Bogotá, en el territorio específico del Barrio Las Cruces, durante los años 2002-2014. Para lograrlo, en un primer momento se hace un análisis conceptual de las relaciones existentes entre intervenciones urbanas y los efectos que estas producen en lo urbano y lo local; en un segundo se identifican los antecedentes que sirvieron para intervenir el barrio, y las intervenciones públicas que llevadas a cabo en éste durante el 2002 – 2014; y en un el tercero se analizan los efectos y las relaciones que tuvieron dichas intervenciones sobre las variables social, espacial y económica del barrio durante el periodo estudiado. Con el fin de verificar si la política de rehabilitación con la que se viene interviniendo dicha zona es coherente con las realidades locales.

Aproximaciones al concepto de propiedad privada del suelo urbano. Estado del arte en latinoamérica 1990 - 2014

El presente trabajo pretende hacer una revisión de la bibliografía latinoamericana con respecto al concepto de propiedad del suelo urbano. Se explica primero el itinerario del concepto a través de la historia, rescatando los puntos más importantes del debate y las particularidades que cada contexto aportó a la formación del concepto actual, para ahondar después en el análisis de la situación del debate en el contexto latinoamericano desde 1990, explicando los puntos de discusión y las posiciones de los autores con respecto a los mismos, para después intentar intuir el devenir futuro del concepto en nuestro continente. En este trabajo se encontró que las problemáticas particulares de las ciudades latinoamericanas tienen una influencia importante en el devenir de la discusión proporcionándole un enfoque diferente en el tratamiento del concepto.

Informality in the City: a Theoretical Analysis

This thesis theoretically studies the relationship between the informal sector (both in the labor and the housing market) and the city structure.

Análisis de la influencia de la construcción del parque tercer milenio y del intercambiador de la Av. de los Comuneros con Av. Carrera Décima en el proceso de deterioro urbano del barrio San Bernardo (1998 – 2014)

Este trabajo analiza la relación que tuvo la construcción de dos proyectos urbanos (parque Tercer Milenio e intercambiador vial Av. de Los Comuneros con Av. Carrera Décima) en el proceso de deterioro del barrio San Bernardo en Bogotá durante el periodo de 1998 a 2014. Enfatiza en las dimensiones físicas y económicas del deterioro a través del análisis de las condiciones de diseño urbano resultantes de la implantación de los proyectos, así como en el comportamiento de los precios de suelo que permiten identificar procesos de obsolescencia económica dentro del barrio.

Breast cancer incidence and overdiagnosis in Catalonia (Spain)

Early detection of breast cancer (BC) with mammography may cause overdiagnosis and overtreatment, detecting tumors which would remain undiagnosed during a lifetime. The aims of this study were: first, to model invasive BC incidence trends in Catalonia (Spain) taking into account reproductive and screening data; and second, to quantify the extent of BC overdiagnosis. We modeled the incidence of invasive BC using a Poisson regression model. Explanatory variables were: age at diagnosis and cohort characteristics (completed fertility rate, percentage of women that use mammography at age 50, and year of birth). This model also was used to estimate the background incidence in the absence of screening. We used a probabilistic model to estimate the expected BC incidence if women in the population used mammography as reported in health surveys. The difference between the observed and expected cumulative incidences provided an estimate of overdiagnosis.Incidence of invasive BC increased, especially in cohorts born from 1940 to 1955. The biggest increase was observed in these cohorts between the ages of 50 to 65 years, where the final BC incidence rates more than doubled the initial ones. Dissemination of mammography was significantly associated with BC incidence and overdiagnosis. Our estimates of overdiagnosis ranged from 0.4% to 46.6%, for women born around 1935 and 1950, respectively.Our results support the existence of overdiagnosis in Catalonia attributed to mammography usage, and the limited malignant potential of some tumors may play an important role. Women should be better informed about this risk. Research should be oriented towards personalized screening and risk assessment tools

La transformació del paisatge litoral de la Costa Brava: Anàlisi de l'evolució (1956-2003), diagnosi de l'estat actual i prognosi de futur

En la tesi es presenta una anàlisi de l'evolució dels canvis succeïts en el paisatge costaner de la Costa Brava (22 municipis litorals) en els darrers cinquanta anys (1956-2003); un estudi de la seva estructura ecopaisatgística, actual i passada, amb una especial èmfasi en la diagnosi de les conseqüències geoambientals de l'esclat urbanístic iniciat a la dècada de 1960, i s'ha determinat quina ha estat la tendència de canvi en els darrers vint-i-cinc anys la qual s'ha utilitzat per a elaborar models explicatius de la dinàmica territorial seguida i projectar-los cap al futur tot dissenyant escenaris probables. A les Bases teòriques s'exposa en quina parcel·la del coneixement científic es situa aquesta recerca i es repassa l'evolució dels diferents corrents i enfocaments que han precedit, dins la Ciència Geogràfica, els estudis sobre transformació del paisatge. Es posa especial en els principis i metodologies que plantegen les dues escoles d'anàlisi del paisatge en que es basa aquesta tesi: la Landscape Ecology i la estructurada a l'entorn del programa internacional Land Use and Land Cover Change (LUCC). S'ha dissenyat una pauta metodològica per a l'anàlisi paisatgística d'un territori a diferents escales: des de l'àmbit regional de tota la Costa Brava (66.230 ha), on es poden detectar les tendències generals, fins l'estudi detallat a escala local, on s'ha pres com a àrea d'estudi tres municipis del centre de la Costa Brava (6.960 Ha): Palamós, Calonge i Castell-Platja d'Aro. Els principals resultats obtinguts són els següents: Una cartografia d'usos i cobertes del sòl de tres períodes temporals i la conseqüent interpretació espacial per a cada etapa: 1957 (situació preturística), 1980 (inici de les actuacions dels ajuntaments democràtics) i 2003 (actualitat). Una anàlisi quantitativa de la transformació del paisatge i de les relacions espacials associades al canvi, a partir de la cartografia d'usos i cobertes del sòl dels tres períodes mapificats (1956, 1980, 2003). Amb l'objectiu d'arribar a definir quina ha estat la dinàmica dels canvis ocorreguts al llarg dels darrers gairebé cinquanta anys. Una anàlisi de l'estructura del mosaic paisatgístic de cadascun dels talls temporals per mitjà de l'aplicació dels principals índexs de l'Ecologia del Paisatge. S'ha analitzat la geometria de la conversió dels usos del sòl i s'han posat de manifest les repercussions ecològiques i paisatgístiques d'aquests canvis. Per una banda, a partir del càlcul i interpretació dels índexos esmentats s'ha analitzat l'evolució de la morfologia i la distribució territorial dels quatre principals usos i cobertes del sòl de la Costa Brava. Per l'altra, per a la Costa Brava centre s'ha analitzat l'estat dels dos sistemes naturals del litoral amb més pressió antròpica: la franja estrictament costanera i les masses forestals. Respecte als tres municipis de la Costa Brava centre s'han tingut en compte en l'anàlisi de l'evolució del paisatge a escala local, les actuacions desenvolupades en l'àmbit urbanístic municipal i les seves conseqüències paisatgístiques i ambientals. A partir de la informació ja processada, s'han detectat les tendències de canvi a partir de models de canvi d'usos i cobertes del sòl. S'han incorporat també els factors biofísics i antròpics, socials i econòmics, condicionants i responsables d'una determinada utilització del territori en cadascun dels tres períodes. Mitjançant l'anàlisi multivariable s'ha intentat descobrir el conjunt de factors que influencien en la taxa i el patró espacial de canvi d'usos i les seves conseqüències territorials. Finalment s'ha aplicat un model de simulació, basat en els automatismes cel·lulars de Markov, per tal de projectar les tendències de canvi i plantejar escenaris futurs, una eina bàsica per a la planificació futura del territori i per al control de les problemàtiques ambientals. Aquestes mesures serveixen per a definir, per a la Costa Brava centre, un patró espacial dels canvis d'usos del sòl a nivell local, i, per al conjunt de la Costa Brava, per a predir, mitjançant models de simulació quantitativa, els possibles desenvolupaments i per estimar els impactes.

The re-urbanization of the city center of Manaus , Brazil - Facing the challenges of informal settlements

Illegal occupation of urban land in Brazil is a widespread phenomenon. Slum dwellers are excluded from the attributes of urban citizenship although they provide the labor force required by low productivity urban services needed by cities. Illegal settlements generate multiple problems for the rest of the city . Its solution is of key relevance to the city in general but also provide an opportunity for the social and economic advancement of slum dwellers. The programs required to attain these results are complex and difficult to implement underscoring the challenges countries will face to attain the Millennium Development Goals of reducing the population living in slums.

Movement of Juvenile Songbirds in Harvested Boreal Forest: Assessing Residency Time and Landscape Connectivity

Little is known about juvenile songbird movement in response to timber harvest, particularly in the boreal forest. If clearcut land cover facilitates movement, the availability of resources may increase. However, if clearcut land cover impedes movement, important post-fledging resources may be rendered inaccessible. Using radio telemetry, we tested the hypothesis that regenerating clearcut land cover would affect the movement of recently independent Yellow-rumped Myrtle Warblers (Dendroica coronata coronata) and Blackpoll Warblers (Dendroica striata) differently than forested land cover owing to intrinsic differences in each land-cover type or in how they are perceived. We found that both species moved extensively before migration. We also found that Blackpoll Warblers were quick to exit local areas composed of clearcut land cover and that both species were quick to exit neighborhoods composed of large proportions of clearcut land cover. However, if individuals encountered clearcut land cover when exiting the neighborhood, movement rate was slowed. Effectively, residency time decreased in clearcut neighborhoods and landscape connectivity was impeded by clearcut land cover. Our results suggest that clearcut land cover may represent low-quality habitat for both species during the post-fledging period. Further research is needed to determine if changes in movement behavior associated with landscape structure affect individual condition and higher-level ecological processes.

Nest Boxes Facilitate Local-Scale Conservation of Common Goldeneye (Bucephala clangula) and Bufflehead (Bucephala albeola) in Alberta, Canada

We tested the general predictions of increased use of nest boxes and positive trends in local populations of Common Goldeneye (Bucephala clangula) and Bufflehead (Bucephala albeola) following the large-scale provision of nest boxes in a study area of central Alberta over a 16-year period. Nest boxes were rapidly occupied, primarily by Common Goldeneye and Bufflehead, but also by European Starling (Sturnus vulgaris). After 5 years of deployment, occupancy of large boxes by Common Goldeneye was 82% to 90% and occupancy of small boxes by Bufflehead was 37% to 58%. Based on a single-stage cluster design, experimental closure of nest boxes resulted in significant reductions in numbers of broods and brood sizes produced by Common Goldeneye and Bufflehead. Occurrence and densities of Common Goldeneye and Bufflehead increased significantly across years following nest box deployment at the local scale, but not at the larger regional scale. Provision of nest boxes may represent a viable strategy for increasing breeding populations of these two waterfowl species on landscapes where large trees and natural cavities are uncommon but wetland density is high.

Effects of Gunnison Sage-Grouse habitat treatment efforts on associated avifauna and vegetation structure

Conservation efforts over the last 20 years for the Gunnison Sage-Grouse (Centrocercus minimus) have involved extensive habitat manipulations done predominantly to improve brood rearing habitat for the grouse. However, the effects of Gunnison Sage-Grouse habitat treatments on sympatric avifauna and responses of vegetation to manipulations are rarely measured, and if they are, it is immediately following treatment implementation. This study examined the concept of umbrella species management by retrospectively comparing density and occupancy of eight sagebrush associated songbird species and six measures of vegetation in treated and control sites. Our results suggested that songbird densities and occupancy changed for birds at the extreme ends of their association with sagebrush and varied with fine-scale habitat structure. We found Brewer’s Sparrows (Spizella breweri) decreased in density on treated sites and Vesper Sparrows (Pooecetes gramineus) increased. Occupancy estimation revealed that Brewer’s Sparrows and Green-tailed Towhees (Pipilo chlorurus) occupied significantly fewer treated points whereas Vesper Sparrows occupied significantly more. Vegetation comparisons between treated and control areas found shrub cover to be 26% lower in treated sites. Lower shrub cover in treated areas may explain the differences in occupancy and densities of the species sampled based on known habitat needs. The fine-scale analysis showed a negative relationship to forb height and cover for the Sage Sparrow (Amphispiza belli) indicating, from vegetation measures showing grass and forb cover during a good precipitation year covered significantly more area in the treatment than the control sites, that Sage Sparrows may also not respond favorably to Gunnison Sage-Grouse habitat treatments. While the concept of an umbrella species is appealing, evidence from this study suggests that conservation efforts aimed at the Gunnison Sage-Grouse may not be particularly effective for conserving other sagebrush obligate species of concern. This is probably due to Gunnison Sage-Grouse habitat management being focused on the improvement of brood rearing habitat which reduces sagebrush cover and promotes development of understory forbs and grasses.

Methods and resources for climate impacts research: achieving synergy

The prediction of climate variability and change requires the use of a range of simulation models. Multiple climate model simulations are needed to sample the inherent uncertainties in seasonal to centennial prediction. Because climate models are computationally expensive, there is a tradeoff between complexity, spatial resolution, simulation length, and ensemble size. The methods used to assess climate impacts are examined in the context of this trade-off. An emphasis on complexity allows simulation of coupled mechanisms, such as the carbon cycle and feedbacks between agricultural land management and climate. In addition to improving skill, greater spatial resolution increases relevance to regional planning. Greater ensemble size improves the sampling of probabilities. Research from major international projects is used to show the importance of synergistic research efforts. The primary climate impact examined is crop yield, although many of the issues discussed are relevant to hydrology and health modeling. Methods used to bridge the scale gap between climate and crop models are reviewed. Recent advances include large-area crop modeling, quantification of uncertainty in crop yield, and fully integrated crop–climate modeling. The implications of trends in computer power, including supercomputers, are also discussed.

Predicted soil organic carbon stocks and changes in Jordan between 2000 and 2030 made using the GEFSOC modelling system

Estimates of soil organic carbon (SOC) stocks and changes under different land use systems can help determine vulnerability to land degradation. Such information is important for countries in and areas with high susceptibility to desertification. SOC stocks, and predicted changes between 2000 and 2030, were determined at the national scale for Jordan using The Global Environment Facility Soil Organic Carbon (GEFSOC) Modelling System. For the purpose of this study, Jordan was divided into three natural regions (The Jordan Valley, the Uplands and the Badia) and three developmental regions (North, Middle and South). Based on this division, Jordan was divided into five zones (based on the dominant land use): the Jordan Valley, the North Uplands, the Middle Uplands, the South Uplands and the Badia. This information was merged using GIS, along with a map of rainfall isohyets, to produce a map with 498 polygons. Each of these was given a unique ID, a land management unit identifier and was characterized in terms of its dominant soil type. Historical land use data, current land use and future land use change scenarios were also assembled, forming major inputs of the modelling system. The GEFSOC Modelling System was then run to produce C stocks in Jordan for the years 1990, 2000 and 2030. The results were compared with conventional methods of estimating carbon stocks, such as the mapping based SOTER method. The results of these comparisons showed that the model runs are acceptable, taking into consideration the limited availability of long-term experimental soil data that can be used to validate them. The main findings of this research show that between 2000 and 2030, SOC may increase in heavily used areas under irrigation and will likely decrease in grazed rangelands that cover most of Jordan giving an overall decrease in total SOC over time if the land is indeed used under the estimated forms of land use. (C) 2007 Elsevier B.V. All rights reserved.

Spatial and temporal scale issues in determining biomass burning regimes in Bolivia and Peru

ATSR-2 active fire data from 1996 to 2000, TRMM VIRS fire counts from 1998 to 2000 and burn scars derived from SPOT VEGETATION ( the Global Burnt Area 2000 product) were mapped for Peru and Bolivia to analyse the spatial distribution of burning and its intra- and inter-annual variability. The fire season in the region mainly occurs between May and October; though some variation was found between the six broad habitat types analysed: desert, grassland, savanna, dry forest, moist forest and yungas (the forested valleys on the eastern slope of the Andes). Increased levels of burning were generally recorded in ATSR-2 and TRMM VIRS fire data in response to the 1997/1998 El Nino, but in some areas the El Nino effect was masked by the more marked influences of socio-economic change on land use and land cover. There were differences between the three global datasets: ATSR-2 under-recorded fires in ecosystems with low net primary productivities. This was because fires are set during the day in this region and, when fuel loads are low, burn out before the ATSR-2 overpass in the region which is between 02.45 h and 03.30 h. TRMM VIRS was able to detect these fires because its overpasses cover the entire diurnal range on a monthly basis. The GBA2000 product has significant errors of commission (particularly areas of shadow in the well-dissected eastern Andes) and omission (in the agricultural zone around Santa Cruz, Bolivia and in north-west Peru). Particular attention was paid to biomass burning in high-altitude grasslands, where fire is an important pastoral management technique. Fires and burn scars from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM) data for a range of years between 1987 and 2000 were mapped for areas around Parque Nacional Rio Abiseo (Peru) and Parque Nacional Carrasco (Bolivia). Burn scars mapped in the grasslands of these two areas indicate far more burning had taken place than either the fires or the burn scars derived from global datasets. Mean scar sizes are smaller and have a smaller range in size between years the in the study area in Peru (6.6-7.1 ha) than Bolivia (16.9-162.5 ha). Trends in biomass burning in the two highland areas can be explained in terms of the changing socio-economic environments and impacts of conservation. The mismatch between the spatial scale of biomass burning in the high-altitude grasslands and the sensors used to derive global fire products means that an entire component of the fire regime in the region studied is omitted, despite its importance in the farming systems on the Andes.

Predicted soil organic carbon stocks and changes in the Brazilian Amazon between 2000 and 2030

Currently we have little understanding of the impacts of land use change on soil C stocks in the Brazilian Amazon. Such information is needed to determine impacts'6n the global C cycle and the sustainability of agricultural systems that are replacing native forest. The aim of this study was to predict soil carbon stocks and changes in the Brazilian Amazon during the period between 2000 and 2030, using the GEFSOC soil carbon (C) modelling system. In order to do so, we devised current and future land use scenarios for the Brazilian Amazon, taking into account: (i) deforestation, rates from the past three decades, (ii) census data on land use from 1940 to 2000, including the expansion and intensification of agriculture in the region, (iii) available information on management practices, primarily related to well managed pasture versus degraded pasture and conventional systems versus no-tillage systems for soybean (Glycine max) and (iv) FAO predictions on agricultural land use and land use changes for the years 2015 and 2030. The land use scenarios were integrated with spatially explicit soils data (SOTER database), climate, potential natural vegetation and land management units using the recently developed GEFSOC soil C modelling system. Results are presented in map, table and graph form for the entire Brazilian Amazon for the current situation (1990 and 2000) and the future (2015 and 2030). Results include soil organic C (SOC) stocks and SOC stock change rates estimated by three methods: (i) the Century ecosystem model, (ii) the Rothamsted C model and (iii) the intergovernmental panel on climate change (IPCC) method for assessing soil C at regional scale. In addition, we show estimated values of above and belowground biomass for native vegetation, pasture and soybean. The results on regional SOC stocks compare reasonably well with those based on mapping approaches. The GEFSOC system provided a means of efficiently handling complex interactions among biotic-edapho-climatic conditions (> 363,000 combinations) in a very large area (similar to 500 Mha) such as the Brazilian Amazon. All of the methods used showed a decline in SOC stock for the period studied; Century and RothC simulated values for 2030 being about 7% lower than those in 1990. Values from Century and RothC (30,430 and 25,000 Tg for the 0-20 cm layer for the Brazilian Amazon region were higher than those obtained from the IPCC system (23,400 Tg in the 0-30 cm layer). Finally; our results can help understand the major biogeochemical cycles that influence soil fertility and help devise management strategies that enhance the sustainability of these areas and thus slow further deforestation. (C) 2007 Elsevier B.V. All rights reserved.