307 research outputs found

    Geometrical construction of quantum groups representations

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    We describe geometrically the classical and quantum inhomogeneous groups G_0=(SL(2, \BbbC)\triangleright \BbbC^2) and G_1=(SL(2, \BbbC)\triangleright \BbbC^2)\triangleright \BbbC by studying explicitly their shape algebras as a spaces of polynomial functions with a quadratic relations.Comment: 16 pages, 1 figur

    Incipient continental rifting: insights from the Okavango Rift Zone, northwestern Botswana

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    In this dissertation aeromagnetic, gravity, and Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) data from the Okavango Rift Zone in northwest Botswana are used to map the distribution of rift and basement structures. The distribution of these structures provide useful insights into the early stages of continental rifting. The objectives of this study are (1) assessing the role of pre-existing structures on rift basin development, (2) characterizing the geometry of the nascent rift basins, (3) documenting fault growth and propagation patterns, and (4) investigating the border fault development --Abstract, page iv

    The Exact Hausdorff Measure of the Zero Set ofFractional Brownian Motion

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    Let {X(t), t∈ℝN} be a fractional Brownian motion in ℝd of index H. If L(0,I) is the local time of X at 0 on the interval I⊂ℝN, then there exists a positive finite constant c(=c(N,d,H)) such that mϕ(X−1(0)∩I)=cL(0,I),m_\phi\bigl(X^{-1}(0)\cap I\bigr)=cL(0,I), where ϕ(t)=tN−dH(log⁥log⁥1t)dH/N\phi(t)=t^{N-dH}(\log\log\frac{1}{t})^{dH/N} , and m φ(E) is the Hausdorff φ-measure ofE. This refines a previous result of Xiao (Probab. Theory Relat. Fields 109: 126-197, 1997) on the relationship between the local time and the Hausdorff measure of zero set for d-dimensional fractional Brownian motion on ℝ

    Hölder properties of local times for fractional Brownian motions

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    We study the local times of fractional Brownian motions for all temporal dimensions, N, spatial dimensions d and Hurst parameters H for which local times exist. We establish a Hölder continuity result that is a refinement of Xiao (Probab Th Rel Fields 109:129-157, 1997). Our approach is an adaptation of the more general attack of Xiao (Probab Th Rel Fields 109:129-157, 1997) using ideas of Baraka and Mountford (1997, to appear), the principal result of this latter paper is contained in this articl

    The Exact Hausdorff Measure of the Zero Set of Fractional Brownian Motion

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    Let {X(t), t is an element of R-N} be a fractional Brownian motion in R-d of index H. If L(0,I) is the local time of X at 0 on the interval I subset of R-N, then there exists a positive finite constant c(=c(N,d,H)) such tha

    Holder properties of local times for fractional Brownian motions

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    We study the local times of fractional Brownian motions for all temporal dimensions, N, spatial dimensions d and Hurst parameters H for which local times exist. We establish a Holder continuity result that is a refinement of Xiao (Probab Th Rel Fields 109:129-157, 1997). Our approach is an adaptation of the more general attack of Xiao (Probab Th Rel Fields 109:129-157, 1997) using ideas of Baraka and Mountford (1997, to appear), the principal result of this latter paper is contained in this article

    Fault Growth and Propagation During Incipient Continental Rifting: Insights from a Combined Aeromagnetic and Shuttle Radar Topography Mission Digital Elevation Model Investigation of the Okavango Rift Zone, Northwest Botswana

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    Digital Elevation Models (DEM) extracted from the Shuttle Radar Topography Mission (SRTM) data and high-resolution aeromagnetic data are used to characterize the growth and propagation of faults associated with the early stages of continental extension in the Okavango Rift Zone (ORZ), northwest Botswana. Significant differences in the height of fault scarps and the throws across the faults in the basement indicate extended fault histories accompanied by sediment accumulation within the rift graben. Faults in the center of the rift either lack topographic expressions or are interpreted to have become inactive, or have large throws and small scarp heights indicating waning activity. Faults on the outer margins of the rift exhibit either (1) large throws or significant scarp heights and are considered older and active or (2) throws and scarp heights that are in closer agreement and are considered young and active. Fault linkages between major fault systems through a process of fault piracy have combined to establish an immature border fault for the ORZ. Thus, in addition to growing in length (by along-axis linkage of segments), the rift is also growing in width (by transferring motion to younger faults along the outer margins while abandoning older faults in the middle). Finally, utilization of preexisting zones of weakness allowed the development of very long faults (\u3e100 km) at a very early stage of continental rifting, explaining the apparent paradox between the fault length versus throw for this young rift. This study clearly demonstrates that the integration of the SRTM DEM and aeromagnetic data provides a 3-D view of the faults and fault systems, providing new insight into fault growth and propagation during the nascent stages of continental rifting

    Increased use of malaria rapid diagnostic tests improves targeting of anti-malarial treatment in rural Tanzania: implications for nationwide rollout of malaria rapid diagnostic tests.

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    ABSTRACT: BACKGROUND: The World Health Organization recommends parasitological confirmation of all malaria cases. Tanzania is implementing a phased rollout of malaria rapid diagnostic tests (RDTs) for routine use in all levels of care as one strategy to increase parasitological confirmation of malaria diagnosis. This study was carried out to evaluated artemisinin combination therapy (ACT) prescribing patterns in febrile patients with and without uncomplicated malaria in one pre-RDT implementation and one post-RDT implementation area. METHODS: A cross-sectional health facility surveys was conducted during high and low malaria transmission seasons in 2010 in both areas. Clinical information and a reference blood film on all patients presenting for an initial illness consultation were collected. Malaria was defined as a history of fever in the past 48 hours and microscopically confirmed parasitaemia. Routine diagnostic testing was defined as RDT or microscopy ordered by the health worker and performed at the health facility as part of the health worker-patient consultation. Correct diagnostic testing was defined as febrile patient tested with RDT or microscopy. Over-testing was defined as a febrile patient tested with RDT or microscopy. Correct treatment was defined as patient with malaria prescribed ACT. Over-treatment was defined as patient without malaria prescribed ACT. RESULTS: A total of 1,247 febrile patients (627 from pre-implementation area and 620 from post-implementation area) were included in the analysis. In the post-RDT implementation area, 80.9% (95% CI, 68.2-89.3) of patients with malaria received recommended treatment with ACT compared to 70.3% (95% CI, 54.7-82.2) of patients in the pre-RDT implementation area. Correct treatment was significantly higher in the post-implementation area during high transmission season (85.9% (95%CI, 72.0-93.6) compared to 58.3% (95%CI, 39.4-75.1) in pre-implementation area (p=0.01). Over-treatment with ACT of patients without malaria was less common in the post-RDT implementation area (20.9%; 95% CI, 14.7-28.8) compared to the pre-RDT implementation area (45.8%; 95% CI, 37.2-54.6) (p<0.01) in high transmission. The odds of overtreatment was significantly lower in post- RDT area (adjusted Odds Ratio (OR: 95%CI) 0.57(0.36-0.89); and much higher with clinical diagnosis adjusted OR (95%CI) 2.24(1.37-3.67) CONCLUSION: Implementation of RDTs increased use of RDTs for parasitological confirmation and reduced over-treatment with ACT during high malaria transmission season in one area in Tanzania. Continued monitoring of the national RDT rollout will be needed to assess whether these changes in case management practices will be replicated in other areas and sustained over time. Additional measures (such as refresher trainings, closer supervisions, etc) may be needed to improve ACT targeting during low transmission seasons

    Role of stigmasterol treatment in alleviating the adverse effects of salt stress in flax plant

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    Abstract The results revealed that application of stigmasterol to salt -stressed flax plants causing significantly increased in growth parameters, membrane stability index, photosynthetic pigment and carbohydrate contents compared with salt-stressed plants untreated with stigmasterol. The level of antioxidant system components (catalase, ascorbic acid peroxidase) and reduced glutathione with increased in response to stigmasterol treatment. Enhanced antioxidant activities helped to decrease oxidative damage from salt and develop tolerance against salt stress in stigmasterol -treated flax plants. Stigmasterol treatment increase in the degree of salt tolerance by improvement of the membrane stability index, photosynthetic activity and carbohydrate contents. The data provided evidence that seeds soaking in stigmasterol reduced the adverse effects of salt stress on flax plants by stimulation of the antioxidant system as a stress protection mechanism
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