Structural Crystallography Development in the 20th Century. Impact in the Biomedical Sciences and Perspectives in this Field

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The City Passing by the River. The San Francisco River Canalization and Construction of Avenida Jiménez de Quesada in Bogota at the Beginning of the 20th Century

The document refers to the San Francisco river canalization and subsequent construction of the Avenida Jiménez de Quesada. Understanding that the project was ascribed to the modernizing policy of the time, the investigation identifies the different stages in the canalization process, and shows its relations with the spatial structure of the city and the local conditions that developed on the river surroundings. The financing of the project through the “property increase duty” permits an illustration of the progress of canalization and construction of the Jiménez Avenue process, providing a less technical and more social meaning to the sequence in which the project executed. Consequently, the document approaches the shaping dynamics of Bogotá´s spatial structure at the beginning of the XX century.

GCSE History : modern world history : 20th century Britain. The revision guide.

Este texto guiado esta dividido en nueve secciones y abarca la historia de Gran Bretaña en el siglo XX. Al final de cada una de las secciones hay un repaso resumido y se formulan preguntas para ayudar a los alumnos a preparar en casa los exámenes del General Certificate Secondary Education (GCSE) y del Oxford, Cambridge and the Royal Society of Arts (OCR), en dististos organismos.

20th Century World History.

Se adapta a los contenidos y enfoques específicos del International Baccalaureate (IB). Incluye las materias y temas de la historia del siglo XX, ruta 2, de este programa de estudios y permita a los estudiantes comparar y contrastar acontecimientos y temas de distintos periodos y regiones. Ofrece, además, gran cantidad de fuentes primarias para el análisis y valoración de los testimonios históricos, así como actividades y puntos de discusión para desarrollar en los alumnos las habilidades de argumentación y redacción de trabajos e investigaciones.

Late-20th-century changes in glacier extent in the Caucasus Mountains, Russia/Georgia

Glaciers occupy an area of similar to 1600 km(2) in the Caucasus Mountains. There is widespread evidence of retreat since the Little Ice Age, but an up-to-date regional assessment of glacier change is lacking. In this paper, satellite imagery (Landsat Thematic Mapper and Enhanced Thematic Mapper Plus) is used to obtain the terminus position of 113 glaciers in the central Caucasus in 1985 and 2000, using a manual delineation process based on a false-colour composite (bands 5, 4, 3). Measurements reveal that 94% of the glaciers have retreated, 4% exhibited no overall change and 2% advanced. The mean retreat rate equates to similar to 8 m a(-1), and maximum retreat rates approach similar to 38 m a(-1). The largest (>10 km(2)) glaciers retreated twice as much (similar to 12 m a(-1)) as the smallest (<1 km(2)) glaciers (similar to 6 m a(-1)), and glaciers at lower elevations generally retreated greater distances. Supraglacial debris cover has increased in association with glacier retreat, and the surface area of bare ice has reduced by similar to 10% between 1985 and 2000. Results are compared to declassified Corona imagery from the 1960s and 1970s and detailed field measurements and mass-balance data for Djankuat glacier, central Caucasus. It is concluded that the decrease in glacier area appears to be primarily driven by increasing temperatures since the 1970s and especially since the mid-1990s. Continued retreat could lead to considerable changes in glacier runoff, with implications for regional water resources.

Glacier shrinkage and climatic change in the Russian Altai from the mid-20th century: An assessment using remote sensing and PRECIS regional climate model

This paper examines changes in the surface area of glaciers in the North and South Chuya Ridges, Altai Mountains in 1952-2004 and their links with regional climatic variations. The glacier surface areas for 2004 were derived from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery. Data from the World Glacier Inventory (WGI)dating to 1952 and aerial photographs from 1952 were used to estimate the changes. 256 glaciers with a combined area of 253±5.1 km2 have been identified in the region in 2004. Estimation of changes in extent of 126 glaciers with the individual areas not less than 0.5 km2 in 1952 revealed a 19.7±5.8% reduction. The observed glacier retreat is primarily driven by an increase in summer temperatures since the 1980s when air temperatures were increasing at a rate of 0.10 - 0.13oC a-1 at the glacier tongue elevation. The regional climate projections for A2 and B2 CO2 emission scenarios developed using PRECIS regional climate model indicate that summer temperatures will increase in the Altai in 2071-2100 by 6-7oC and 3-5oC respectively in comparison with 1961-1990 while annual precipitation will increase by 15% and 5%. The length of the ablation season will extend from June-August to the late April – early October. The projected increases in precipitation will not compensate for the projected warming and glaciers will continue to retreat in the 21st century under both B2 and A2 scenarios.

Is there regime behavior in monsoon convection in the late 20th century?

Mixture model techniques are applied to a daily index of monsoon convection from ERA‐40 reanalysis to show regime behavior. The result is the existence of two significant regimes showing preferred locations of convection within the Asia/Western‐North Pacific domain, with some resemblance to active‐break events over India. Simple trend analysis over 1958–2001 shows that the first regime has become less frequent while the second becomes much more dominant. Both undergo a change in structure contributing to the total OLR trend over the ERA‐40 period. Stratifying the data according to a large‐scale dynamical index of monsoon interannual variability, we show the regime occurrence to be strongly perturbed by the seasonal condition, in agreement with conceptual ideas. This technique could be used to further examine predictability issues relating the seasonal mean and intraseasonal monsoon variability or to explore changes in monsoon behavior in centennial‐scale model integrations.

War, Peace and World Orders from Antiquity until the 20th century

Chapters contributed by experts on each period examine how world views have determined the view of war and peace, and the conduct of war, throughout European history.