252 research outputs found
Soil organic carbon stocks in mountain periglacial areas of northern Patagonia (Argentina)
No full textThis study presents a detailed soil organic carbon (SOC) inventory for two areas in the mountain periglacial zone of northern Patagonia (altitude range c. 1,400–2,100 m). We describe plant cover and soil profiles at twenty-seven sites representing the main land cover classes and landform types at and above the treeline. The mean SOC 0–100 cm storage is 2.31 kg C m−2 for the combined study areas, which includes 69 percent of bare ground surfaces with negligible SOC stocks. If we consider the vegetated alpine belt only, mean SOC 0–100 cm storage increases to 6.96 kg C m−2. Solifluction has resulted in areas with dense plant cover and deep soil profiles with mean SOC 0–100 cm of 17.1 to 18.3 kg C m−2 and a maximum total stock of 51.5 kg C m−2. Lowest SOC storages of 0.13 to 0.63 kg C m−2 are found in bare and sparsely vegetated high-elevation areas with shallow and stony soils developed in patterned ground (stripes and sorted circles). Projected future increases in ambient temperature will likely result in an upward shift of the alpine vegetation belt with soil development, creating new areas of ecosystem carbon storage.Fil: Fröjd, Christina. Stockholms Universitet; SueciaFil: Trombotto, Dario Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Scheer, Christopher. Stockholms Universitet; SueciaFil: Pecker Marcosig, Ivanna. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Kuhry, Peter. Stockholms Universitet; Sueci
An Architecture for Art: The new M HKA
No full textAntwerp has a very important port history and the existing lock underneath the new location for the M HKA is a reminder of that. In my design for the new M HKA, the underground lock will be transformed into exhibition and forum spaces, while a new building will be built above ground. Public stairs are positioned in the centre of the building, connecting the spaces under and above ground in one big continuous movement. The stairs come up inside a bay window with a view over the water just outside the main building volume, providing a scenic view of the water and connecting the park side to the waterfront. These stairs connect the park and the water as well as the industrial roughness of the lock space with the domestic intimacy of the gallery spaces and form a focal point in the building.The facade is composed of panels made from offset glass blocks with wooden strips in between. For this facade I designed a new element which doesn't use mortar the connect the blocks and is demountable. Creating a translucent and transparent facade around the building which lets light through during the day and lights up at night.Architecture, Urbanism and Building Sciences | Interiors Buildings Citie
Bax's 'Sea Symphony'
No full textBax's Fourth is the only one of his symphonies that alludes explicitly to an extramusical stimulus: 'a rough sea at flood-tide on a sunny day'. This essay contextualizes Bax's frequent use of sea imagery throughout his oeuvre, noting in particular the peripherality of the composer's observation of the sea from the liminal position of the shore. It then considers how the idea of the sea in the Fourth Symphony is related to several musical features (motivic coherence, thematic expansion, formal anomalies), and how the sea is central to the underlying conflict in the work between nature and humanity
Fin-de-Siècle Britain: Imperialism and Wagner in the Music of Gustav Holst.
No full textScholarship on the life of the composer Gustav Holst has been dominated by the writings of his daughter Imogen, which are increasingly in dispute in light of fresh data and interpretation. The present dissertation offers a fresh view of Gustav Holst’s life in this respect, in relation to two important elements of his cultural environment: British Imperialism, and the music of Richard Wagner.
The first section of the dissertation considers the role of Imperialism in Holst’s formative years in Cheltenham, as well as illustrating his portrayal of the East as both inferior and “other” to the West in King Estmere (1903) and Beni Mora (1910). This demonstrates that Holst’s view of the East was multifaceted and not simply the reverent approach found in Sanskrit inspired works such as Savitri (1908) and The Cloud Messenger (1912).
The second section of the dissertation examines the development of Holst’s personal music idiom through his dynamic relationship with the music of Richard Wagner. Holst’s three operas, Sita (1899-1906), Savitri, and The Perfect Fool (1908-1923), illustrate his progression from emulation, to personalization, and finally to parody of Wagner, questioning received interpretations that Wagner was detrimental to Holst’s development.
The consideration of Holst and his music in this way highlights the many questions that characterize our understanding of his life and music, and contributes to the ongoing process of reconnecting Holst to the culture in which he lived.PhDMusic: MusicologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/57706/2/cscheer_1.pd
Determining groundwater velocity with DTS at the Máximakanaal and in the Horstermeerpolder
No full textA suggested approach for determining groundwater flow in unconsolidated aquifers is tested. Performing a heat pulse response test by using a heat- and fibre-optic cable should result in a vertical profile of groundwater velocities. These cables are installed by using direct push ensuring the direct contact between cable and aquifer. The suggested approach is tested with two case studies. The first case study near the Máximakanaal was meant to determine if the canal is leaking. This experiment failed during the installation which was discovered after analyzing the results. The mistakes that were made during this case study have been analyzed and are discussed. The second case study was not performed by the author of this thesis. Nonetheless, the measurements of this case study enabled the completion of retrieving groundwater velocities from distributed temperature sensing and reviewing the approach
Biosphere-atmosphere-exchange of C and N trace gases and microbial N turnover processes in irrigated agricultural systems of the Aral Sea Basin, Uzbekistan
No full textLand-use and agricultural practices affect the soil microbial carbon (C) and nitrogen (N) turnover and hence the biosphere-atmosphere exchange of greenhouse gasses (GHG), namely N2O, CH4 and CO2. In view of the global importance of irrigated agriculture, it is crucial to understand how and to which extent this land-use system interferes with the terrestrial N and C cycles and contributes to the global source strength of atmospheric GHG. Up to now, knowledge of trace gas exchange and N turnover from irrigated agriculture in arid and semiarid regions is much less developed than in other climate zones. Therefore, this study aims at providing more detailed insights into the biosphere-atmosphere exchange of trace gases and the underlying soil microbial transformation processes of the irrigated agricultural systems in the Aral Sea Basin (ASB), Uzbekistan. A two-year field study was carried out to quantify and compare emissions of N2O and CH4 in various annual and perennial land-use systems dominating in the study region Khorezm in western Uzbekistan: irrigated cotton, winter wheat and rice crops, a poplar plantation as well as a natural Tugai (floodplain) forest. Irrigated agricultural production in the ASB was shown to be a relevant source of GHG especially due to high emissions of N2O during the annual cropping of wheat and cotton. Average N2O emissions ranged from 10 to 150 µg N2O N m 2h-1 with highest N2O emissions in the cotton fields, covering a similar range described in previous studies of other irrigated cropping systems. Seasonal variations in N2O emissions were principally controlled by fertilization and irrigation management. Very high N2O emissions of up to 3000 µg N2O-N m-2 h-1 were measured in periods directly following N fertilizer application in combination with irrigation events. These “emission pulses” accounted for 80-95% of the total N2O emissions over the cropping season for cotton and wheat. Cumulated emissions over one season varied from 0.5 to 6.5 kg N2O-N ha-1. The unfertilized poplar plantation showed high N2O emissions over the entire study period (30µg N2O N m 2h-1), whereas only negligible fluxes of N2O (2O N m 2h-1) occurred in the natural Tugai forest. Observations of significant CH4 fluxes were restricted to the flooded rice fields, with mean flux rates of 32 mg CH4 m 2d-1 and a seasonal total of 35.2 kg CH4 ha-1. The global warming potential (GWP) of the N2O and CH4 fluxes was highest under rice and cotton, with seasonal changes between 500 and 3000 kg CO2 eq.ha-1. The biennial cotton-wheat-rice crop rotation commonly practiced in the region averaged a GWP of 2500 kg CO2 eq.ha 1 year-1. In addition, laboratory incubation studies were conducted to assess the aggregated gaseous N losses composed of NO, N2O, and N2 from fertilized and irrigated agricultural fields in the ASB. NO3- fertilizer and irrigation water were applied to the incubation vessels to assess its influence on the gaseous N emissions. Under the soil conditions, naturally found after concomitant irrigation and fertilization, denitrification was the dominant process and N2 the main gaseous product of denitrification. Based on the results of these laboratory incubation studies, the magnitude of N2 emissions for the different field research sites of irrigated cotton could be estimated to be in the range of 24±9 to 175±65 kg-N ha-1season-1, while emissions of NO were only of minor importance (between 0.1 and 0.7 kg-N ha-1 season-1). The findings demonstrate that under the current agricultural practices in the irrigated dryland soils of the ASB, denitrification is a major pathway of N losses and that beside N2O extensive amounts of N fertilizer are lost as N2 to the atmosphere. Moreover, the experimental design of this study allows assessing the potential for reducing GHG emissions from these land-use systems. It is argued that there is wide scope for reducing the GWP of this agroecosystem by (i) optimization of fertilization and irrigation practices and (ii) conversion of annual cropping systems into perennial forest plantations, especially on less profitable, marginal lands.Biosphäre-Atmosphäre Austausch von C/N Spurengasen und mikrobielle N Umsetzungsprozesse in bewässerten, landwirtschaftlichen Produktions-systemen des Aralseebeckens, Usbekistan Die mikrobiellen Umsetzungsprozesse von Kohlenstoff (C) und Stickstoff (N) in Böden und der damit verbundene Austausch von Treibhausgasen zwischen Biosphäre und Atmosphäre werden maßgeblich von der Landnutzung und den landwirtschaftlichen Methoden beeinflusst. Angesichts der weltweiten Bedeutung von bewässerter Landwirtschaft ist es äußerst wichtig zu verstehen, in wie weit diese landwirtschaftlichen Systeme die globalen N und C Kreisläufe beeinflussen und zu den globalen Treibhausgasemissionen beitragen. Im Gegensatz zu den landwirtschaftlichen Systemen der temperaten Klimazonen ist über N und C Spurengasemissionen aus bewässerter Landwirtschaft in ariden und semiariden Gebieten nur sehr wenig bekannt. Um einen wesentlichen Beitrag zur Schließung dieser Forschungsdefizite zu leisten, konzentrierte sich diese Studie auf den Austausch von strahlungsaktiven Spurengasen zwischen Biosphäre und Atmosphäre und die hiermit assoziierten mikrobiellen N Umsetzungsprozesse in den Böden der bewässerten landwirtschaftlichen Systeme im Aralsee-Becken (ASB) von Usbekistan. Dafür wurde über einen Zeitraum von zwei Jahren in verschiedenen einjährigen und mehrjährigen Landnutzungssystemen die Emissionen der Treibhausgase Lachgas (N2O) und Methan (CH4) untersucht. Ausgewählt wurden Landnutzungsysteme die typisch für das Untersuchungsgebiet Khorezm, in West-Usbekistan, sind: bewässerter Baumwoll-, Winter Weizen- und Reisanbau sowie eine Pappel-Plantage und der natürliche „Tugai“ Auenwald entlang des Amu Darya Flusses. Es konnte festgestellt werden, dass der bewässerte Landbau im ASB insbesondere aufgrund von hohen N2O Emissionen aus dem Baumwoll- und Weizenanbau eine maßgebliche Quelle von Treibhausgasen darstellt. In den einjährigen Anbausystemen wurden mittlere N2O Emissionsraten zwischen 10 und 150 µg N2O N m-2h-1 festgestellt, wobei die höchsten Emissionen in Baumwollfeldern gemessen wurden. Über die gesamte Saison wurden die N2O Emissionen hauptsächlich von Düngung und Bewässerung beeinflusst. Dabei traten extrem hohe N2O Emissionen (bis zu 3000 µg N2O-N m-2 h-1) auf, wenn mineralischer N-Dünger direkt vor der Bewässerung appliziert wurde. Diese „Emissionsspitzen“ hatten einen Anteil von 80-95% an den Gesamtemissionen von N2O bezogen auf die Vegetationsperiode von Baumwolle und Weizen. Insgesamt variierten die N2O Emissionen über eine Saison von 0,5 bis 6,5 kg N2O-N ha-1. In der ungedüngten Pappel-Plantage wurden über den gesamten Messzeitraum hohe N2O Emissionen (30 µg N2O N m-2h-1) gemessen, wohingegen in dem Tugai Wald lediglich äußerst kleine Flüsse von N2O (2O N m-2h-1) festgestellt wurden. Bedeutende CH4 Emissionen traten nur in den gefluteten Reisfeldern auf, mit einer durchschnittlichen Flussrate von 32 mg CH4 m-2d-1 und einer Gesamtemission über die Vegetationsperiode von 35,2 kg CH4 ha-1. Das Treibhauspotenzial der N2O und CH4 Flüsse, dargestellt als CO2-Äquivalent, war am höchsten für den Reis- und Baumwollanbau, wobei auf den verschiedenen Messflächen die Gesamtemission einer Saison von 500 bis zu 3000 kg CO2 eq.ha-1 variierte. Für eine zweijährige Rotation von Baumwolle-Weizen und Reis, wie sie typisch für das Untersuchungsgebiet ist, konnte ein durchschnittliches Treibhauspotenzial von 2500 kg CO2 eq.ha-1 Jahr-1ermittelt werden. Zusätzlich wurden im Labor Inkubationsversuche an intakten Bodensäulen durchgeführt um die gasförmigen Stickstoffverluste, bestehend aus NO, N2O, und N2, der gedüngten und bewässerten Anbausysteme des ASB zu erfassen. Ammoniumnitrat Dünger wurde zusammen mit Wasser auf die Bodensäulen appliziert, um den Einfluss von gleichzeitiger Düngung und Bewässerung zu simulieren. Es konnte gezeigt werden, dass nach synchroner Düngung und Bewässerung Denitrifikation der vorherrschende Prozess in den Böden ist, und dass der größte Teil des Nitrats vollständig zu molekularem Stickstoff (N2) denitrifiziert wird. Aufgrund dieser Ergebnisse war es möglich für Baumwolle die Größenordnung der gasförmigen N Verluste von den verschiedenen Messflächen abzuschätzen. Demnach wurden von den einzelnen Baumwollfeldern zwischen 24±9 und 175±65 kg-N ha-1Saison-1 als N2 emittiert, während nur geringe Mengen von NO freigesetzt wurden (zwischen 0,1 und 0,7 kg-N ha-1 Saison-1). Diese Studie konnte somit zeigen, dass unter den gegenwärtigen landwirtschaftlichen Methoden im ASB, erhebliche Mengen von Stickstoff durch Denitrifikation als N2 an die Atmosphäre abgegeben werden. Ferner erlaubte das experimentelle Design dieser Studie Möglichkeiten einer Reduktion des Ausstoßes von Treibhausgasen aus diesen Anbausystemen abzuschätzen. Abschließend kann festgestellt werden, dass durch (i) eine Optimierung der Dünge- und Bewässerungsmethoden und (ii) einen Wechsel von einjährigen Feldfrüchten auf mehrjährige Baumplantagen, insbesondere auf unrentablen, marginalen Boden, das Treibhauspotential dieses landwirtschaftlichen Produktionssystems wesentlich reduziert werden kann.</p
Methane and nitrous oxide fluxes in annual and perennial land-use systems of the irrigated areas in the Aral Sea Basin
No full textLand use and agricultural practices can result in important contributions to the global source strength of atmospheric nitrous oxide (N2O) and methane (CH4). However, knowledge of gas flux from irrigated agriculture is very limited. From April 2005 to October 2006, a study was conducted in the Aral Sea Basin, Uzbekistan, to quantify and compare emissions of N2O and CH4 in various annual and perennial land-use systems: irrigated cotton, winter wheat and rice crops, a poplar plantation and a natural Tugai (floodplain) forest. In the annual systems, average N2O emissions ranged from 10 to 150 μg N2O-N m−2 h−1 with highest N2O emissions in the cotton fields, covering a similar range of previous studies from irrigated cropping systems. Emission factors (uncorrected for background emission), used to determine the fertilizer-induced N2O emission as a percentage of N fertilizer applied, ranged from 0.2% to 2.6%. Seasonal variations in N2O emissions were principally controlled by fertilization and irrigation management. Pulses of N2O emissions occurred after concomitant N-fertilizer application and irrigation. The unfertilized poplar plantation showed high N2O emissions over the entire study period (30 μg N2O-N m−2 h−1), whereas only negligible fluxes of N2O (<2 μg N2O-N m−2 h−1) occurred in the Tugai. Significant CH4 fluxes only were determined from the flooded rice field: Fluxes were low with mean flux rates of 32 mg CH4 m−2 day−1 and a low seasonal total of 35.2 kg CH4 ha−1. The global warming potential (GWP) of the N2O and CH4 fluxes was highest under rice and cotton, with seasonal changes between 500 and 3000 kg CO2 eq. ha−1. The biennial cotton–wheat–rice crop rotation commonly practiced in the region would average a GWP of 2500 kg CO2 eq. ha−1 yr−1. The analyses point out opportunities for reducing the GWP of these irrigated agricultural systems by (i) optimization of fertilization and irrigation practices and (ii) conversion of annual cropping systems into perennial forest plantations, especially on less profitable, marginal lands
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