Global surface net-radiation at 5 km from MODIS Terra

Reliable and fine resolution estimates of surface net-radiation are required for estimating latent and sensible heat fluxes between the land surface and the atmosphere. However, currently, fine resolution estimates of net-radiation are not available and consequently it is challenging to develop multi-year estimates of evapotranspiration at scales that can capture land surface heterogeneity and are relevant for policy and decision-making. We developed and evaluated a global net-radiation product at 5 km and 8-day resolution by combining mutually consistent atmosphere and land data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on board Terra. Comparison with net-radiation measurements from 154 globally distributed sites (414 site-years) from the FLUXNET and Surface Radiation budget network (SURFRAD) showed that the net-radiation product agreed well with measurements across seasons and climate types in the extratropics (Wilmott’s index ranged from 0.74 for boreal to 0.63 for Mediterranean sites). Mean absolute deviation between the MODIS and measured net-radiation ranged from 38.0 ± 1.8 W∙m−2 in boreal to 72.0 ± 4.1 W∙m−2 in the tropical climates. The mean bias was small and constituted only 11%, 0.7%, 8.4%, 4.2%, 13.3%, and 5.4% of the mean absolute error in daytime net-radiation in boreal, Mediterranean, temperate-continental, temperate, semi-arid, and tropical climate, respectively. To assess the accuracy of the broader spatiotemporal patterns, we upscaled error-quantified MODIS net-radiation and compared it with the net-radiation estimates from the coarse spatial (1° × 1°) but high temporal resolution gridded net-radiation product from the Clouds and Earth’s Radiant Energy System (CERES). Our estimates agreed closely with the net-radiation estimates from the CERES. Difference between the two was less than 10 W•m−2 in 94% of the total land area. MODIS net-radiation product will be a valuable resource for the science community studying turbulent fluxes and energy budget at the Earth’s surface.

Background Traffic Modeling for Large-Scale Network Simulation

Network simulation is an indispensable tool for studying Internet-scale networks due to the heterogeneous structure, immense size and changing properties. It is crucial for network simulators to generate representative traffic, which is necessary for effectively evaluating next-generation network protocols and applications. With network simulation, we can make a distinction between foreground traffic, which is generated by the target applications the researchers intend to study and therefore must be simulated with high fidelity, and background traffic, which represents the network traffic that is generated by other applications and does not require significant accuracy. The background traffic has a significant impact on the foreground traffic, since it competes with the foreground traffic for network resources and therefore can drastically affect the behavior of the applications that produce the foreground traffic. This dissertation aims to provide a solution to meaningfully generate background traffic in three aspects. First is realism. Realistic traffic characterization plays an important role in determining the correct outcome of the simulation studies. This work starts from enhancing an existing fluid background traffic model by removing its two unrealistic assumptions. The improved model can correctly reflect the network conditions in the reverse direction of the data traffic and can reproduce the traffic burstiness observed from measurements. Second is scalability. The trade-off between accuracy and scalability is a constant theme in background traffic modeling. This work presents a fast rate-based TCP (RTCP) traffic model, which originally used analytical models to represent TCP congestion control behavior. This model outperforms other existing traffic models in that it can correctly capture the overall TCP behavior and achieve a speedup of more than two orders of magnitude over the corresponding packet-oriented simulation. Third is network-wide traffic generation. Regardless of how detailed or scalable the models are, they mainly focus on how to generate traffic on one single link, which cannot be extended easily to studies of more complicated network scenarios. This work presents a cluster-based spatio-temporal background traffic generation model that considers spatial and temporal traffic characteristics as well as their correlations. The resulting model can be used effectively for the evaluation work in network studies.

Cosmopolitan Imperialism: Mann, Sarmiento, and the Origins of Universal Education in Nineteenth-Century Boston and Buenos Aires

To reveal the theories and practices that linked education to the development within the cities of Boston and Buenos Aires, and in turn to the development of US and Argentina nationalism, “Cosmopolitan Imperialism” centers on two education reformers, Horace Mann (1776-1859) and Domingo Faustino Sarmiento (1811-1888). Mann and Sarmiento formed part of a supra-national community where liberal intellectual elites created a republic of letters, or perhaps better said, a republic of schools. As different versions of education branched out from a common Atlantic origin during the nineteenth century, Mann and Sarmiento searched for those ideas that better fit their national projects, a local project that started in the cities and moved to the interior parts of the country. In Boston and Buenos Aires, modern nationalism intertwined with imperial projects. This dissertation thus analyzes nationalism and reform in the nineteenth-century as an imperial project led by cosmopolitan intellectual elites. While we might expect to find Mann and Sarmiento’s ideas on education to be centered on their national experiences, looking to Europe for inspiration, this dissertation shows that it was quite the opposite. Educational ideas developed within an interconnected network and traveled within the North-South axis connecting Boston with Buenos Aires. This framework moves the focus from the interchange of ideas between America and Europe and places it within the American continent. At the same time, it allows us to consider Latin American and the US as both creators and recipients of educational ideas. There is a traditional way of talking about nationalism and reform in the nineteenth-century, especially in terms of education and educational policies. It is common to imagine that in the US, and even more certainly in Latin America, educated elites looked to the so-called West for inspiration. The argument is that they ended up adapting foreign models to their local and internal contexts. This dissertation challenges that idea and shows that different versions of education developed from a shared Atlantic milieu in which reformers in certain cities saw themselves as part of the same cosmopolitan empires.

Iridium concentrations and abundances of meteoritic ejecta from the Eltanin impact in sediment cores from POLARSTERN cruise ANT-XII/4

The abundances of meteoritic ejecta from the Eltanin asteroid impact have been examined in seven sediment cores recovered by the FS Polarstern during expedition ANT XII/4 using elemental concentrations of iridium and weights of coarse (>500 ?m) ejecta debris. Three cores with well-preserved impact deposits, PS2704-1, PS2708-1, and PS2709-1, each contain Ir and ejecta fluences similar to those found previously in USNS Eltanin core E13-4. Small Ir anomalies and traces of ejecta were found in cores PS2706-1 and PS2710-1, but since these cores lack well-defined deposits, these are considered to be reworked and not representative of the fallout. No evidence of ejecta was found in cores PS2702-1 and PS2705-1. These results confirm earlier speculation that the Eltanin impact resulted in deposits of ejecta with up to 1 g/cm**2 of debris over a wide area of the ocean floor. However, there are still large uncertainties over the actual regional or global extent of this unique sediment deposit.

Color reflectance and XRF drill core scanner data of ANDRILL core AND-2A

The compositional record of the AND-2A drillcore is examined using petrological, sedimentological, volcanological and geochemical analysis of clasts, sediments and pore waters. Preliminary investigations of basement clasts (granitoids and metasediments) indicate both local and distal sources corresponding to variable ice-volume and ice-flow directions. Low abundance of sedimentary clasts (e.g., arkose, litharenite) suggests reduced contributions from sedimentary covers while intraclasts (e.g., diamictite, conglomerate) attest to intrabasinal reworking. Volcanic material includes pyroclasts (e.g., pumice, scoria), sediments and lava. Primary and reworked tephra layers occur within the Early Miocene interval (1093 to 640 metres below sea floor mbsf). The compositions of volcanic clasts reveal a diversity of alkaline types derived from the McMurdo Volcanic Group. Finer-grained sediments (e.g., sandstone, siltstone) show increases in biogenic silica and volcanic glass from 230 to 780 mbsf and higher proportions of terrigenous material c. 350 to 750 mbsf and below 970 mbsf. Basement clast assemblages suggest a dominant provenance from the Skelton Glacier - Darwin Glacier area and from the Ferrar Glacier - Koettlitz Glacier area. Provenance of sand grains is consistent with clast sources. Thirteen Geochemical Units are established based on compositional trends derived from continuous XRF scanning. High values of Fe and Ti indicate terrigenous and volcanic sources, whereas high Ca values signify either biogenic or diagenic sources. Highly alkaline and saline pore waters were produced by chemical exchange with glass at moderately elevated temperatures.

Towards convection-resolving, global atmospheric simulations with the Model for Prediction Across Scales (MPAS) v3.1: an extreme scaling experiment, links to sourcecode of model and grides

The Model for Prediction Across Scales (MPAS) is a novel set of Earth system simulation components and consists of an atmospheric model, an ocean model and a land-ice model. Its distinct features are the use of unstructured Voronoi meshes and C-grid discretisation to address shortcomings of global models on regular grids and the use of limited area models nested in a forcing data set, with respect to parallel scalability, numerical accuracy and physical consistency. This concept allows one to include the feedback of regional land use information on weather and climate at local and global scales in a consistent way, which is impossible to achieve with traditional limited area modelling approaches. Here, we present an in-depth evaluation of MPAS with regards to technical aspects of performing model runs and scalability for three medium-size meshes on four different high-performance computing (HPC) sites with different architectures and compilers. We uncover model limitations and identify new aspects for the model optimisation that are introduced by the use of unstructured Voronoi meshes. We further demonstrate the model performance of MPAS in terms of its capability to reproduce the dynamics of the West African monsoon (WAM) and its associated precipitation in a pilot study. Constrained by available computational resources, we compare 11-month runs for two meshes with observations and a reference simulation from the Weather Research and Forecasting (WRF) model. We show that MPAS can reproduce the atmospheric dynamics on global and local scales in this experiment, but identify a precipitation excess for the West African region. Finally, we conduct extreme scaling tests on a global 3?km mesh with more than 65 million horizontal grid cells on up to half a million cores. We discuss necessary modifications of the model code to improve its parallel performance in general and specific to the HPC environment. We confirm good scaling (70?% parallel efficiency or better) of the MPAS model and provide numbers on the computational requirements for experiments with the 3?km mesh. In doing so, we show that global, convection-resolving atmospheric simulations with MPAS are within reach of current and next generations of high-end computing facilities.

Dinoflagellate cysts in western equatorial Atlantic surface sediments

In contrast to the wide range of studies carried out in temperate and high-latitude oceanic regions, only a few studies have focused on recent and Holocene organic-walled dinoflagellate cyst assemblages from the tropics. This information is, however, essential for fully understanding the ability of species to adapt to different oceanographic regimes, and ultimately their potential application to local and regional palaeoenvironmental and palaeoceanographic reconstructions. Surface sediment samples of the western equatorial Atlantic Ocean north of Brazil, an area greatly influenced by Amazon River discharge waters, were therefore analysed in detail for their organic-walled dinoflagellate cyst content. A diverse association of 43 taxa was identified, and large differences in cyst distribution were observed. The cyst thanatocoenosis in bottom sediments reflects the seasonal advection of Amazon River discharge water through the Guyana Current and the North Equatorial Countercurrent well into the North Atlantic. To establish potential links between cyst distribution and the environmental conditions of the upper water column, distribution patterns were compared with mean temperature, salinity, density and stratification gradients within the upper water column (0-100 m) over different times of the year, using correspondence analysis and canonical correspondence analysis. The analyses show that differences in these parameters only play a subordinate role in determining species distribution. Instead, nutrient availability, or related factors, dominates the distribution pattern. The only possible indicators of slightly reduced salinities are Trinovantedinium applanatum and Lingulodinium machaerophorum. Four assemblage groups of cyst taxa with similar environmental affinities related to specific water masses/currents can be distinguished and have potential for palaeoenvironmental reconstruction.

The European Union Foreign Policy in the Caucasus and Central Asia: The Limitations of the Opening towards the East

This article intends to study the evolution of the European Union foreign policy in the Southern Caucasus and Central Area throughout the Post-Cold War era. The aim is to analyze Brussels’ fundamental interests and limitations in the area, the strategies it has implemented in the last few years, and the extent to which the EU has been able to undermine the regional hegemons’ traditional supremacy. As will be highlighted, the Community’s chronic weaknesses, the local determination to preserve sovereignty and an increasing international geopolitical competition undermine any European aspiration to become a pre-eminent actor at the heart of the Eurasian continent in the near future.

Late-career international migration and reproductive work. A comparison between Peruvian and Ukrainian women in the Southern Europe

Research on the relationship between reproductive work and women´s life trajectories including the experience of labour migration has mainly focused on the case of relatively young mothers who leave behind, or later re-join, their children. While it is true that most women migrate at a younger age, there are a significant number of cases of men and women who move abroad for labour purposes at a more advanced stage, undertaking a late-career migration. This is still an under-estimated and under-researched sub-field that uncovers a varied range of issues, including the global organization of reproductive work and the employment of migrant women as domestic workers late in their lives. By pooling the findings of two qualitative studies, this article focuses on Peruvian and Ukrainian women who seek employment in Spain and Italy when they are well into their forties, or older. A commonality the two groups of women share is that, independently of their level of education and professional experience, more often than not they end up as domestic and care workers. The article initially discusses the reasons for late-career female migration, taking into consideration the structural and personal determinants that have affected Peruvian and Ukrainian women’s careers in their countries of origin and settlement. After this, the focus is set on the characteristics of domestic employment at later life, on the impact on their current lives, including the transnational family organization, and on future labour and retirement prospects. Apart from an evaluation of objective working and living conditions, we discuss women’s personal impressions of being domestic workers in the context of their occupational experiences and family commitments. In this regard, women report varying levels of personal and professional satisfaction, as well as different patterns of continuity-discontinuity in their work and family lives, and of optimism towards the future. Divergences could be, to some extent, explained by the effect of migrants´ transnational social practices and policies of states.

La ética hacker frente al capitalismo netárquíco: software libre y peer production en las iniciativas de Economía Colaborativa en Andalucía

En los últimos años el término Economía Colaborativa se ha popularizado sin que, hasta el momento, haya sido definido de manera inequívoca. Bajo esta denominación se engloban experiencias tan diversas como bancos de tiempo, huertos urbanos, startups o grandes plataformas digitales. La proliferación de este tipo de iniciativas puede relacionarse con una multiplicidad de factores tales como el desarrollo tecnológico, la recesión económica y otras crisis superpuestas (medioambiental, de cuidados, de valores, de lo político) y un cierto cambio en los valores sociales. Entre 2014-2015 se han realizado dos investigaciones en Andalucía de manera casi paralela y con una metodología similar. La primera de ellas pretendía identificar prácticas de Economía Colaborativa en el entorno universitario. La segunda investigación identificaba experiencias de emprendimiento a nivel autonómico. A luz de los resultados obtenidos se plantea la siguiente cuestión sobre la naturaleza misma de la Economía Colaborativa: ¿nos encontramos ante prácticas postcapitalistas que abren el camino a una sociedad más justa e igualitaria o, más bien, estamos ante una respuesta del capital para, una vez más, seguir extrayendo de manera privada el valor que se genera socialmente? Este artículo, partiendo del análisis del conjunto de iniciativas detentadas en Andalucía, se centra en aquellas basadas en el software libre y la producción digital concluyendo cómo, gracias a la incorporación de ciertos aspectos de la ética hacker y las lógicas del conocimiento abierto, éstas pueden situarse dentro de un escenario de fomento de los comunes globales frente a las lógicas imperantes del capitalismo netárquico. 

Characterisation of Large Disturbance Rotor Angle and Voltage Stability in Interconnected Power Networks with Distributed Wind Generation

Wind generation in highly interconnected power networks creates local and centralised stability issues based on their proximity to conventional synchronous generators and load centres. This paper examines the large disturbance stability issues (i.e. rotor angle and voltage stability) in power networks with geographically distributed wind resources in the context of a number of dispatch scenarios based on profiles of historical wind generation for a real power network. Stability issues have been analysed using novel stability indices developed from dynamic characteristics of wind generation. The results of this study show that localised stability issues worsen when significant penetration of both conventional and wind generation is present due to their non-complementary characteristics. In contrast, network stability improves when either high penetration of wind and synchronous generation is present in the network. Therefore, network regions can be clustered into two distinct stability groups (i.e. superior stability and inferior stability regions). Network stability improves when a voltage control strategy is implemented at wind farms, however both stability clusters remain unchanged irrespective of change in the control strategy. Moreover, this study has shown that the enhanced fault ride-through (FRT) strategy for wind farms can improve both voltage and rotor angle stability locally, but only a marginal improvement is evident in neighbouring regions.

A secure authentication and key management scheme for Wireless Sensors Network

In recent years, the adaptation of Wireless Sensor Networks (WSNs) to application areas requiring mobility increased the security threats against confidentiality, integrity and privacy of the information as well as against their connectivity. Since, key management plays an important role in securing both information and connectivity, a proper authentication and key management scheme is required in mobility enabled applications where the authentication of a node with the network is a critical issue. In this paper, we present an authentication and key management scheme supporting node mobility in a heterogeneous WSN that consists of several low capabilities sensor nodes and few high capabilities sensor nodes. We analyze our proposed solution by using MATLAB (analytically) and by simulation (OMNET++ simulator) to show that it has less memory requirement and has good network connectivity and resilience against attacks compared to some existing schemes. We also propose two levels of secure authentication methods for the mobile sensor nodes for secure authentication and key establishment.

Macroinvertebrate Diversity in Urban and Rural Ponds: Implications for Freshwater Biodiversity Conservation

Ponds are among the most biodiverse freshwater ecosystems, yet face significant threats from removal, habitat degradation and a lack of legislative protection globally. Information regarding the habitat quality and biodiversity of ponds across a range of land uses is vital for the long term conservation and management of ecological resources. In this study we examine the biodiversity and conservation value of macroinvertebrates from 91 lowland ponds across 3 land use types (35 floodplain meadow, 15 arable and 41 urban ponds). A total of 224 macroinvertebrate taxa were recorded across all ponds, with urban ponds and floodplain ponds supporting a greater richness than arable ponds at the landscape scale. However, at the alpha scale, urban ponds supported lower faunal diversity (mean: 22 taxa) than floodplain (mean: 32 taxa) or arable ponds (mean: 30 taxa). Floodplain ponds were found to support taxonomically distinct communities compared to arable and urban ponds. A total of 13 macroinvertebrate taxa with a national conservation designation were recorded across the study area and 12 ponds (11 floodplain and 1 arable pond) supported assemblages of high or very high conservation value. Pond conservation currently relies on the designation of individual ponds based on very high biodiversity or the presence of taxa with specific conservation designations. However, this site specific approach fails to acknowledge the contribution of ponds to freshwater biodiversity at the landscape scale. Ponds are highly appropriate sites outside of protected areas (urban/arable), with which the general public are already familiar, for local and landscape scale conservation of freshwater habitats.

Redes interorganizacionais e inovação: o caso do pólo joalheiro de Belém

This work is a case study based on Belém Jewelry Pole, whose main issue is to understand how the social network (which the Pole is inserted) influences on innovation process on this area. The main objective is to analyze how interorganizational networks impacted/impact on the potential for innovation, creating both limits and opportunities for the companies development. The adopted method analyzed the historical jewelry industry trajectory since the beginning of mineral extraction in the city of Itaituba (in the Pará State) until nowadays. Primary and secondary data were used allowing the view of the dynamics of the network during transformation periods of the main involved actors in the process. The prospect of embeddedness structural as analysis technique allowed verifying the quality of interactors ties, as well as the visualization of their structures. During the jewelry industry trajectory was verified a change in the quality of social relations, modifying the information flow, trust and associations of various links in the production chain. Both direct and indirect ties facilitated the access to remote networks entering new information related to new products, processes and market aspects. This interaction has led to raising the innovation potential causing a qualitative and quantitative improvement in competitiveness of organizations. Some embedded ties allowed the formation of partnerships bringing various economic earnings for those involved in the relationship. Thus, it is understood how aspects related to the position, architecture and quality of ties in a wide social network influenced on the innovation process and eventual jewelry industry trajectory

Adsorption Calorimetry for Energy Conversion Technologies: Applications in Organic Photovoltaics, Catalysis, and Atomic Layer Deposition

Thesis (Ph.D.)--University of Washington, 2016-07