2,314 research outputs found
Optimal representation of our knowledge about seismic sources for PSHA in low deformation areas
characterization of the seismic sources, the definition of the attenuation law and the computation of the probabilistic seismic hazard. Our work is focus on the first two steps. Given that most active faults are not characterized well enough, in low deformation areas, seismic sources are generally defined as areal zones, delimited with finite boundary polygons, within which the geological features of active tectonics and the seismicity are deemed homogeneous. Besides the lack of data (e.g., narrow range of recorded magnitudes), the application of this representation generates different problems: 1) a large sensitivity of resulting hazard maps on the location of zone boundaries, while these boundaries are set by expert decision; 2) the zoning can not represent any variation in faulting mechanism; 3) the seismicity rates are distributed throughout the zones and we lose the location of the determinant information used for their calculation. We propose an exploratory study for an alternative procedure in area source modeling. This method allows to obtain a limit, and its uncertainties, between two zones, separated by two different seismic activity rates. Since we obtain this limit, we can recover the seismic activity rates for both zones.The important features for this developed method is the location and magnitude of the largest earthquakes. Given than the largest events are not recorded by instruments,we decide to use the Bakun and Wentworth method (1997) to better characterize the epicentral region and the magnitude of the instrumental earthquakes. Because of the unusual shape of the isoseismal lines of the 1909 Benavente event, we decided to apply this methodology to this event. The result show that the estimated epicenter (Kárnik, 1969) is within all the confidence-level. Because of the low magnitude estimation, we decide to test the sensibility of this method to the attenuation law. A new law is developed using a compilation of macroseismic reports and will be used to re-estimate the epicentral region and the magnitude of the 1909 Benavente event.The logarithmic trends of intensities with the median distance suggests a logarithmic form for the attenuation law. Then, this law will be used to re-evaluate the estimations of both epicentral region and magnitude of the 1909 Benavente event
Recherche sur l'origine des fausses réactions positives dans le diagnostic sérologique de la péripneumonie contagieuse bovine
Des bovins ont été expérimentalement immunisés respectivement avec Mycoplasma (M) capricolum, M. mycoides subsp. mycoides (LC), M. mycoides subsp. capri, M. species groupe 7 de LEACH. Pendant 8 semaines ces animaux ont fait l'objet d'un suivi sérologique vis-à-vis de l'agent de la péripneumon ie contagieuse bovine (PPCB), par le test immunoenzymatique (ELISA), en fixation du complément (FC) et en hémagglutination passive (HAP), l'HAP étant effectuée également vis-à-vis des valences d'immunisation. En FC, utilisée selon la méthode standardisée, des réactions croisées, souvent transitoires, sont notées chez les bovins immunisés par le groupe 7 et les 2 "mycoides" caprins. Ce modèle experimental pourrait expliquer certaines réactions aspécifiques naturelles rencontrées exceptionnellement lors du diagnostic sérologique de la PPC
Extreme Mountain Ultra-Marathon Leads to Acute but Transient Increase in Cerebral Water Diffusivity and Plasma Biomarkers Levels Changes.
Background: Pioneer studies demonstrate the impact of extreme sport load on the human brain, leading to threatening conditions for athlete's health such as cerebral edema. The investigation of brain water diffusivity, allowing the measurement of the intercellular water and the assessment of cerebral edema, can give a great contribution to the investigation of the effects of extreme sports on the brain. We therefore assessed the effect of supra-physiological effort (extreme distance and elevation changes) in mountain ultra-marathons (MUMs) athletes combining for the first time brain magnetic resonance imaging (MRI) and blood parameters. Methods:This longitudinal study included 19 volunteers (44.2 ± 9.5 years) finishing a MUM (330 km, elevation + 24000 m). Quantitative measurements of brain diffusion-weighted images (DWI) were performed at 3 time-points: Before the race, upon arrival and after 48 h. Multiple blood biomarkers were simultaneously investigated. Data analyses included brain apparent diffusion coefficient (ADC) and physiological data comparisons between three time-points. Results:The whole brain ADC significantly increased from baseline to arrival (p = 0.005) and then significantly decreased at recovery (p = 0.005) to lower values than at baseline (p = 0.005). While sodium, potassium, calcium, and chloride as well as hematocrit (HCT) changed over time, the serum osmolality remained constant. Significant correlations were found between whole brain ADC changes and osmolality (p = 0.01), cholesterol (p = 0.009), c-reactive protein (p = 0.04), sodium (p = 0.01), and chloride (p = 0.002) plasma level variations. Conclusions:These results suggest the relative increase of the inter-cellular volume upon arrival, and subsequently its reduction to lower values than at baseline, indicating that even after 48 h the brain has not fully recovered to its equilibrium state. Even though serum electrolytes may only indirectly indicate modifications at the brain level due to the blood brain barrier, the results concerning osmolality suggest that body water might directly influence the change in cerebral ADC. These findings establish therefore a direct link between general brain inter-cellular water content and physiological biomarkers modifications produced by extreme sport
Role of the Netrin-like Domain of Procollagen C-Proteinase Enhancer-1 in the Control of Metalloproteinase Activity
The netrin-like (NTR) domain is a feature of several extracellular proteins, most notably the N-terminal domain of tissue inhibitors of metalloproteinases (TIMPs), where it functions as a strong inhibitor of matrix metalloproteinases and some other members of the metzincin superfamily. The presence of a C-terminal NTR domain in procollagen C-proteinase enhancers (PCPEs), proteins that stimulate the activity of astacin-like tolloid proteinases, raises the possibility that this might also have inhibitory activity. Here we show that both long and short forms of the PCPE-1 NTR domain, the latter beginning at the N-terminal cysteine known to be critical for TIMP activity, show no inhibition, at micromolar concentrations, of several members of the metzincin superfamily, including matrix metalloproteinase-2, bone morphogenetic protein-1 (a tolloid proteinase), and different ADAMTS (a disintegrin and a metalloproteinase with thrombospondin motifs) proteinases from the adamalysin family. In contrast, we report that the NTR domain within PCPE-1 leads to superstimulation of bone morphogenetic protein-1 activity in the presence of heparin and heparan sulfate. These observations point to a new mechanism whereby binding to cell surface-associated or extracellular heparin-like sulfated glycosaminoglycans might provide a means to accelerate procollagen processing in specific cellular and extracellular microenvironments
IL-1 beta and TNF alpha Promote Monocyte Viability through the Induction of GM-CSF Expression by Rheumatoid Arthritis Synovial Fibroblasts
Background. Macrophages and synovial fibroblasts (SF) are two major cells implicated in the pathogenesis of rheumatoid arthritis (RA). SF could be a source of cytokines and growth factors driving macrophages survival and activation. Here, we studied the effect of SF on monocyte viability and phenotype. Methods. SF were isolated from synovial tissue of RA patients and CD14+ cells were isolated from peripheral blood of healthy donors. SF conditioned media were collected after 24 hours of culture with or without stimulation with TNFα or IL-1β. Macrophages polarisation was studied by flow cytometry. Results. Conditioned medium from SF significantly increased monocytes viability by 60% compared to CD14+ cells cultured in medium alone . This effect was enhanced using conditioned media from IL-1β and TNFα stimulated SF. GM-CSF but not M-CSF nor IL34 blocking antibodies was able to significantly decrease monocyte viability by 30% when added to the conditioned media from IL-1β and TNFα stimulated SF . Finally, monocyte cultured in presence of SF conditioned media did not exhibit a specific M1 or M2 phenotype. Conclusion. Overall, rheumatoid arthritis synovial fibroblasts stimulated with proinflammatory cytokines (IL-1β and TNFα) promote monocyte viability via GM-CSF but do not induce a specific macrophage polarization
The phase diagram of the lattice Calogero-Sutherland model
We introduce a {\it lattice} version of the Calogero Sutherland model adapted
to describe pairwise interacting steps with discrete positions on a
vicinal surface. The configurational free energy is obtained within a transfer
matrix method. The full phase diagram for attractive and for repulsive
interaction is deduced. For attraction, critical temperatures of faceting
transitions are found to depend on step density.Comment: latex PRBCalogSuth.tex, 6 files, 4 pages [SPEC-S00/900
Применение уравнений Френеля в статистическом анализе эллипсометрических данных - определение оптических показателей анодно полученных плёнок из TiO2
Оптические показатели TI02 плёнок , определены эллилсометрически
при стандартных ех-ситовых условиях в видимой
спектральной области. Плёнки , изготовленные из Ti02, получены
анодным окислением электрополирован:ной титановой поверхности
в области потенциала от О до 100 V. Путём вычисления:,
с помощью измеренных эллипсометрических параметров L1 и Р
и Френеловых уравнений, показано , что численное значение
оптических показателей уменьшае11ся: с изменением т олщины
плёнки, и что у тол·стых плёнок они получают постоянные значения:.
Исползован и ем различных спос обо в выч исления: пок.азано,
каким образом можно получить наиболее точные рез у ль таты,
т. е. самая: маленькая: погрешность при статистической
обработке эллипсометрических д анных
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