508 research outputs found

    Normalization and Trace Element Contamination of Soils in a Karstic Polje - An Example from the Sinjsko Polje, Croatia

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    Estimation of the anthropogenic over natural contribution in the chemical content of soils and sediments is very important but not easy to measure. Normalization based on either aluminium or iron, as reference conservative elements having supposed natural distributions, is a useful tool in solving this problem. However, several independent factors can influence the normalization procedure, which if not taken into account could lead to completely erroneous conclusions about the origin of the particular elevated concentrations of certain elements. Therefore, a great deal of caution should be exercised during application of the normalization procedure. Analytical data from 95 soil samples from the Sinjsko polje enabled us to critically apply this procedure. Linear regression analysis, evaluation of enrichment factors and trend surface analysis with the construction of appropriate maps were used to test the procedure. Presuming an existing linear dependence between the conservative element and the heavy metal it is possible with the use of linear regression to simultaneously define the heavy metal geochemical background (baseline) and to isolate natural and/or anthropogenic outliers (anomalies). Coupled with geographic plotting facilities this type of outlier-screening is used to locate areas of man made pollution. Statistical treatment of selected elements included the calculation of means, standard deviations and other estimates of basic statistic parameters. Evaluation of enrichment factors reveals the dependence of this parameter upon four main factors: the choice of reference element; the choice of reference material; the homogeneity of reference element distribution in the study area; and correlation of particular element with reference element. Examination of trends is a common procedure in the analysis of geochemical maps. Its purpose is to segregate the underlying trend that possibly pervades the study area, from the local variations, that is, the “noise” or “background”. Statistical analysis, as suggested by the results in this work, would be more properly used over general areas in the karstic terrain, with different geological, geomorphologic and hydrogeological characteristics, rather than being focused on the relatively small phenomena such as poljes, with many local geologic, hydrogeological and geochemical constraints

    Anti-Jo-1 Syndrome presenting as cryptogenic organizing pneumonia

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    AbstractA 50-year-old Chinese lady presented with subacute onset of dyspnoea, bilateral infiltrates on chest X-ray and type I respiratory failure. There were minor symptoms of arthralgia and myalgia. Subsequent investigations confirmed that she had organizing pneumonia, polymyositis and serum anti-Jo-1 antibody. Treatment with corticosteroids resulted in prompt improvement of the respiratory condition and myositis

    Raspodjela elemenata u tragovima u površinskim sedimentima Vranskog jezera i tlima otoka Cresa

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    This paper presents a study of major and trace element distribution and an evaluation of their environmental geochemical aspects in the surface sediments of Vrana Lake and the topsoil within its catchment area. The concentrations of 22 elements were determined in 30 lake sediment samples and 60 topsoil samples covering the lake catchment area and the whole island of Cres. The element to Al ratios fall into three main groups: the group of elements that show no difference in ratios in soils and lake sediments: Ni, Co, Mn, Th, Zn, Ba, Ti, K, V, Na, and H; elements that are enriched in the sediments: Ca, Sr, Cd, Pb, Ba and Mg; and elements that are depleted in the lake sediments: Cu, P, Fe, Cr, and La. Long-range air pollution is probably the main reason why the content of metals, especially lead, is increased in the lake sediments, although a local source, from road transport, as indicated by soil data from the catchment area, could also be an important source of Pb. Some pollutants in the soils of the catchment area, such as Cu and Hg from agro-chemical sources, were not determined in elevated concentrations in the lake sediments. Comparison of element/Al indexes from this study with the other studies of surface materials in the region show mutually similar sources, with loess and flysch as two geochemical end-members.U radu se daje pregled raspodjele glavnih elemenata i onih u tragovima u površinskim sedimentima Vranskog jezera i tlima na otoku Cresu, te se na temelju izra|enih analiza daje pregled mogućih geokemijskih promjena u okolišu. Određene su koncentracije 22 elementa u 30 uzoraka jezerskog sedimenta i 60 uzoraka tla koje pokriva slivno područje jezera i otoka Cresa. Na temelju omjera pojedinih elemenata i aluminija utvrđene su tri geokemijske grupe elemenata; prvu grupu čine elementi koji ne pokazuju razliku u omjerima element/Al u tlima i sedimentima: Ni, Co, Mn, Th, Zn, Ba, Ti, K, V, Na i H; elementi koji pokazuju obogaćenje u sedimentima: Ca, Sr, Cd, Pb, Ba i Mg, te grupa elemenata koja je obogaćena u tlima; Cu, P, Fe, Cr i La. Povišene koncentracije olova u jezerskim sedimentima moguće je tumačiti kao posljedicu atmosferskog taloženja iz udaljenih industrijskih izvora a koncentracije utvrđene u tlima, na lokacijama na širem području prometnice koja prolazi istočnom stranom slivnog područja jezera, upućuju i na mogućnost lokalnog utjecaja automobilskog prometa. Neki potencijalno toksični elementi (Hg i Cu) koji su utvrđeni u povišenim koncentracijama u tlima slivnog područja, nisu utvrđeni kao povišeni u samom jezerskom sedimentu. Usporedbom omjera element/Al dobivenih u ovom radu sa rezultatima istraživanja površinskih materijala drugih autora sa šireg područja pokazuju da detritični materijal potječe iz istih izvora sa lesom i naslagama fliša kao dva krajnja geokemijska člana

    Granulocyte-targeted therapies for airway diseases

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    The average respiration rate for an adult is 12–20 breaths per minute, which constantly exposes the lungs to allergens and harmful particles. As a result, respiratory diseases, which includes asthma, chronic obstructive pulmonary disease (COPD) and acute lower respiratory tract infections (LTRI), are a major cause of death worldwide. Although asthma, COPD and LTRI are distinctly different diseases with separate mechanisms of disease progression, they do share a common feature – airway inflammation with intense recruitment and activation of granulocytes and mast cells. Neutrophils, eosinophils, basophils, and mast cells are crucial players in host defense against pathogens and maintenance of lung homeostasis. Upon contact with harmful particles, part of the pulmonary defense mechanism is to recruit these cells into the airways. Despite their protective nature, overactivation or accumulation of granulocytes and mast cells in the lungs results in unwanted chronic airway inflammation and damage. As such, understanding the bright and the dark side of these leukocytes in lung physiology paves the way for the development of therapies targeting this important mechanism of disease. Here we discuss the role of granulocytes in respiratory diseases and summarize therapeutic strategies focused on granulocyte recruitment and activation in the lungs

    Modeling reaction time within a traffic simulation model

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    Human reaction time has a substantial effect on modeling of human behavior at a microscopic level. Drivers and pedestrian do not react to an event instantaneously; rather, they take time to perceive the event, process the information, decide on a response and finally enact their decision. All these processes introduce delay. As human movement is simulated at increasingly fine-grained resolutions, it becomes critical to consider the delay due to reaction time if one is to achieve accurate results. Most existing simulators over-simplify the reaction time implementation to reduce computational overhead and memory requirements. In this paper, we detail the framework which we are developing within the SimMobility Short Term Simulator (a microscopic traffic simulator), which is capable of explicitly modeling reaction time for each person in a detailed, flexible manner. This framework will enable modelers to set realistic reaction time values, relying on the simulator to handle implementation and optimization considerations. Following this, we report our findings demonstrating the impact of reaction time on traffic dynamics within several simulation scenarios. The findings indicate that in the incorporation of reaction time within microscopic simulations improves the traffic dynamics that produces more realistic traffic condition.Singapore-MIT Alliance for Research and Technolog

    SimMobility Short-Term: An Integrated Microscopic Mobility Simulator

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    This paper presents the development of an integrated microscopic mobility simulator, SimMobility Short-Term (ST). The simulator is integrated because its models, inputs and outputs, simulated components, and code base are integrated within a multiscale agent- and activity-based simu- lation platform capable of simulating different spatiotemporal resolutions and accounting for different levels of travelers’ decision making. The simulator is microscopic because both the demand (agents and its trips) and the supply (trip realization and movements on the network) are microscopic (i.e., modeled individually). Finally, the simulator has mobility because it copes with the multimodal nature of urban networks and the need for the flexible simulation of innovative transportation ser - vices, such as on-demand and smart mobility solutions. This paper follows previous publications that describe SimMobility’s overall framework and models. SimMobility is an open-source, multiscale platform that considers land use, transportation, and mobility-sensitive behavioral models. SimMobility ST aims at simulating the high-resolution movement of agents (traffic, transit, pedestrians, and goods) and the operation of different mobility services and control and information systems. This paper presents the SimMobility ST modeling framework and system architecture and reports on its successful calibration for Singapore and its use in several scenarios of innovative mobility applications. The paper also shows how detailed performance measures from SimMobility ST can be integrated with a daily activity and mobility patterns simulator. Such integration is crucial to model accurately the effect of different technologies and service operations at the urban level, as the identity and preferences of simulated agents are maintained across temporal decision scales, ensuring the consistency and accuracy of simulated accessibility and performance measures of each scenario.Singapore. National Research Foundation (CREATE program)Singapore-MIT Alliance. Center. Future Urban Mobility Interdisciplinary Research Grou

    A comparative study of arbitration algorithms for the Alpha 21364 pipelined router

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    Interconnection networks usually consist of a fabric of interconnected routers, which receive packets arriving at their input ports and forward them to appropriate output ports. Unfortunately, network packets moving through these routers are often delayed due to conflicting demand for resources, such as output ports or buffer space. Hence, routers typically employ arbiters that resolve conflicting resource demands to maximize the number of matches between packets waiting at input ports and free output ports. Efficient design and implementation of the algorithm running on these arbiters is critical to maximize network performance.This paper proposes a new arbitration algorithm called SPAA (Simple Pipelined Arbitration Algorithm), which is implemented in the Alpha 21364 processor's on-chip router pipeline. Simulation results show that SPAA significantly outperforms two earlier well-known arbitration algorithms: PIM (Parallel Iterative Matching) and WFA (Wave-Front Arbiter) implemented in the SGI Spider switch. SPAA outperforms PIM and WFA because SPAA exhibits matching capabilities similar to PIM and WFA under realistic conditions when many output ports are busy, incurs fewer clock cycles to perform the arbitration, and can be pipelined effectively. Additionally, we propose a new prioritization policy called the Rotary Rule, which prevents the network's adverse performance degradation from saturation at high network loads by prioritizing packets already in the network over new packets generated by caches or memory.Mukherjee, S.; Silla Jiménez, F.; Bannon, P.; Emer, J.; Lang, S.; Webb, D. (2002). A comparative study of arbitration algorithms for the Alpha 21364 pipelined router. ACM SIGPLAN Notices. 37(10):223-234. doi:10.1145/605432.605421S223234371
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