454 research outputs found
Sedimentology-based reconstructions of paleoclimate changes in the Central Andes in response to the uplift of the Andes, Arica region between 19 and 21°S latitude, northern Chile
We focus on the sedimentological record of the Middle Miocene to modern deposits in the Andes of northern Chile between 19 and 21°S. These sediments, deposited at the Western Escarpment of the Central Depression, indicate successively more moisture on the western margin of the Altiplano and the Western Cordillera where the sources are. At the Pacific Coast, 20-Ma-old exposure ages and salic gypsisols reflect an existing and ongoing hyperarid climate. We interpret the increased divergence of climates between the Coast and the Altiplano as consequence of the Andean rise to elevations higher than approximately 2,500m a.s.l., when the topography of the Altiplano was sufficiently high and areally extensive to attract Atlantic moisture. Accordingly, the inferred general increase in run-off was closely coupled with the uplift of the Andes if the steady rise model applies. In case that the rapid rise model for Andean uplift is correct, the inferred changes in sediment transport would have occurred independently of uplift, requiring an alternative, yet unknown drive
Comprehensive Security Research to Contribute to Critical Infrastructure Protection Contributions to Security Governance in Disaster Risk Reduction
Critical infrastructure protection (CIP) has become a major issue in civil security, emergency management and natural hazard management. The all-hazard approach has gained ground on the international scale, and the “comprehensive approach” in security policies and security research has been advanced in order to meet current and future threats based on better integrated information, assessment, policies and capabilities. This paper aims to showcase this “comprehensive approach”, highlighting its character and cross-links to CI and natural hazard and disaster management. The paper also contributes to a broader perspective on CIP by addressing current European political concepts and socio-cultural conditions, as well as possible future EU roles. A focus is put on international critical infrastructure (CI) risks, and results from an Integrated Risk Taxonomy are presented. The paper concludes with proposing socio-cultural aspects for future research topics related to CI risks and security governance
Methods to Integrate Considerations on Culture, Ethics and Citizen Acceptance Into Urban Planning for Resilience Enhancing and Vulnerability Reduction
This paper presents selected relevant research results from the EU FP7 project VITRUV (“Vulnerability Identification Tools for Resilience Enhancements of Urban Environments”), relating to methods to integrate consideration on culture and ethics aspects, including citizen acceptance, into conceptual urban planning. While security aspects do not always figure prominently in urban planning, much of that planning has effects on citizens’ security. Security aspects obviously have an influence on how built environment is changed and developed. Conversely, the way in which built environment is changed and developed influences the security of infrastructures and society as a whole, both in manifest and in latent ways. Putting one focus on ‘soft’, such as cultural, aspects in urban planning, related parts of VITRUV will help urban planners identify how their planning decisions may directly or indirectly affect societal security. In this context, security means a high level of safeguard for the infrastructure, the supply of goods and services as well as for the commonly acquired values of a community. By identifying and validating practical methods to integrate social and cultural aspects in an urban planning tool, project results will facilitate the consideration of the multiple dimensions of threats and vulnerabilities in their context of urban planning. This among other things includes appropriate addressing of gaps between ‘factual’ security and citizens’ ‘felt’ security
Geospatial Web Mining for Emergency Management
Emergency management is a domain where information has to be gathered,
aggrega
ted, and visualized dynamically and quickly. By providing the right
information at the right time, the chaos phase between the occurrence of a disaster and
the start of well
-
organized relief measures can be significantly shortened (Paulheim et
al. 2009).
T
he information needed in an emergency scenario can be quite diverse. For
example, a person planning an evacuation may need to know about companies that can
transport people, and places that can serve as emergency shelters. For the first, bus and
taxi compa
nies, logistics companies as well as rental car providers may be taken into
account. The latter may include hotels and schools as well as sports arenas and concert
venues.
Although all this information is available on the web, it cannot be easily accessed.
Since such non
-
trivial categories such as
buildings that can serve as emergency shelter
are not sharply defined, one cannot simply enter
emergency shelter
into Google and
retrieve a list of emergency shelters. Instead, lots of subsequent manual searches h
ave
to be performed, and the results have to be aggregated by hand. Visual exploration is
even more difficult.
While several emergency management tools exist (cf. (Paulheim et al. 2009) for a
survey), this concern has not been addressed in this context yet. In this paper, we
introduce a prototype which allows for a
-
priori crawling the web for relevant
information on objects belonging to non
-
trivial categories and provide the aggregated
results as an OGC compliant web feature service for visual exploration
Atrial Natriuretic Peptide Protects against Histamine-Induced Endothelial Barrier Dysfunction in Vivo
Endothelial barrier dysfunction is a hallmark of many severe pathologies, including sepsis or atherosclerosis. The cardiovascular hormone atrial natriuretic peptide (ANP) has increasingly been suggested to counteract endothelial leakage. Surprisingly, the precise in vivo relevance of these observations has never been evaluated. Thus, we aimed to clarify this issue and, moreover, to identify the permeability-controlling subcellular systems that are targeted by ANP. Histamine was used as important pro-inflammatory, permeability-increasing stimulus. Measurements of fluorescein isothiocyanate (FITC)-dextran extravasation from venules of the mouse cremaster muscle and rat hematocrit values were performed to judge changes of endothelial permeability in vivo. It is noteworthy that ANP strongly reduced the histamine-evoked endothelial barrier dysfunction in vivo. In vitro, ANP blocked the breakdown of transendothelial electrical resistance (TEER) induced by histamine. Moreover, as judged by immunocytochemistry and Western blot analysis, ANP inhibited changes of vascular endothelial (VE)-cadherin, β-catenin, and p120ctn morphology; VE-cadherin and myosin light chain 2 (MLC2) phosphorylation; and F-actin stress fiber formation. These changes seem to be predominantly mediated by the natriuretic peptide receptor (NPR)-A, but not by NPR-C. In summary, we revealed ANP as a potent endothelial barrier protecting agent in vivo and identified adherens junctions and the contractile apparatus as subcellular systems targeted by ANP. Thus, our study highlights ANP as an interesting pharmacological compound opening new therapeutic options for preventing endothelial leakage
Theoretical determination of surface roughness during high-speed milling and grinding
Аналитически установлено, что высокоскоростное фрезерование располагает значительными технологическими возможностями с точки зрения уменьшения шероховатости поверхности при одновременном увеличении производительности обработки. Установлено также, что при шлифовании уменьшение шероховатости поверхности связано с уменьшением производительности. Наиболее прогрессивным методом шлифования, обеспечивающим одновременно увеличение производительности и уменьшение шероховатости поверхности, является глубинное шлифование с небольшой скоростью детали, которое характеризуется меньшей производительностью по сравнению с высокоскоростным фрезерованием.The paper presents the results of theoretical studies of the surface roughness during milling and grinding. It is shown that high-speed milling has significant technological capabilities in terms of reducing surface roughness, because cutting data parameters are included in the calculated dependencies obtained to determine surface roughness with higher degrees than during grinding. This applies in particular to the speed of rotation of the cutter. Therefore, with its increase, it becomes possible to significantly reduce the surface roughness while increasing the processing capacity, which opens up broad prospects for the practical use of high-speed milling. It is established that during grinding, a decrease in surface roughness is associated with a decrease in productivity, and this reduces the efficiency of processing. The most progressive method of grinding, providing b oth an increase in productivity and a reduction in surface roughness, is deep-grinding at a low speed of the part. However, it is characterized by lower productivity in comparison with high-speed milling
Extent of posterolateral tibial plateau impaction fracture correlates with anterolateral complex injury and has an impact on functional outcome after ACL reconstruction
PURPOSE
The impact of posterolateral tibial plateau impaction fractures (TPIF) on posttraumatic knee stability in the setting of primary anterior cruciate ligament (ACL) tear is unknown. The main objective was to determine whether increased bone loss of the posterolateral tibial plateau is associated with residual rotational instability and impaired functional outcome after ACL reconstruction.
METHODS
A cohort was identified in a prospective enrolled study of patients suffering acute ACL injury who underwent preoperative standard radiographic diagnostics and clinical evaluation. Patients were included when scheduled for isolated single-bundle hamstring autograft ACL reconstruction. Exclusion criteria were concurrent anterolateral complex (ALC) reconstruction (anterolateral tenodesis), previous surgery or symptoms in the affected knee, partial ACL tear, multi-ligament injury with an indication for additional surgical intervention, and extensive cartilage wear. On MRI, bony (TPIF, tibial plateau, and femoral condyle morphology) and ligament status (ALC, concomitant collateral ligament, and meniscus injuries) were assessed by a musculoskeletal radiologist. Clinical evaluation consisted of KT-1000, pivot-shift, and Lachman testing, as well as Tegner activity and IKDC scores.
RESULTS
Fifty-eight patients were included with a minimum follow-up of 12 months. TPIF was identified in 85% of ACL injuries (n = 49). The ALC was found to be injured in 31 of 58 (53.4%) cases. Pearson analysis showed a positive correlation between TPIF and the degree of concomitant ALC injury (p < 0.001). Multiple regression analysis revealed an increased association of high-grade TPIF with increased lateral tibial convexity (p = 0.010). The high-grade TPIF group showed worse postoperative Tegner scores 12 months postoperatively (p = 0.035).
CONCLUSION
Higher degrees of TPIFs are suggestive of a combined ACL/ALC injury. Moreover, patients with increased posterolateral tibial plateau bone loss showed lower Tegner activity scores 12 months after ACL reconstruction.
LEVEL OF EVIDENCE
III
Techno-Economic Optimization and Benchmarking of a Solar-Only Powered Combined Cycle with High-Temperature TES Upstream the Gas Turbine
This work presents a techno-economic parametric study of an innovative central receiver solar thermal power plant layout that applies the combined cycle (CC) as thermodynamic power cycle and a multi-tower solar field configuration together with open volumetric air receivers (OVARs). The topping gas turbine (GT) is powered by an air–air heat exchanger (two heat exchanger trains in the case of reheat). In order to provide dispatchability, a high-temperature thermocline TES system is placed upstream the gas turbine. The aim is threefold, (i) investigating whether the multi-tower concept has a techno-economic advantage with respect to conventional single-tower central receiver plants, (ii) indicating the techno-economic optimum power plant configuration, and (iii) benchmarking the techno-economic optimum of the CC plant against that of a conventional single-cycle Rankine steam plant with the same receiver and TES technology. It is concluded that the multi-tower configuration has a techno-economic advantage with respect to the conventional single-tower arrangement above a total nominal solar power level of about 150 MW. However, the benchmarking of the CC against a Rankine single-cycle power plant layout shows that the CC configuration has despite its higher solar-to-electric conversion efficiency a higher LCOE. The gain in electricity yield is not enough to outweigh the higher investment costs of the more complex CC plant layout
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