36 research outputs found

    Joint inversion of teleseismic and GOCE gravity data: application to the Himalayas

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    Our knowledge and understanding of the 3-D lithospheric structure of the Himalayas and the Tibetan Plateau is still challenging although numerous geophysical studies have been performed in the region. The GOCE satellite mission has the ambitious goal of mapping Earth's gravity field with unprecedented precision (i.e. an accuracy of 1-2 mGal for a spatial resolution of 100 km) to observe the lithosphere and upper-mantle structure. Consequently, it gives new insights in the lithospheric structure beneath the Himalayas and the Tibetan Plateau. Indeed, the GOCE gravity data now allow us to develop a new strategy for joint gravimetry-seismology inversion. Combined with teleseismic data over a large region in a joint inversion scheme, they will lead to lithospheric velocity-density models constrained in two complementary ways. We apply this joint inversion scheme to the Hi-CLIMB (Himalayan-Tibetan Continental Lithosphere during Mountain Building) seismological network which was deployed in South Tibet and the Himalayas for a 3-yr period. The large size of the network, the high quality of the seismological data and the new GOCE gravity data set allow us to image the entire lithosphere of this active area in an innovative way. We image 3-D low velocity and density structures in the middle crust that fit the location of discontinuous low S-velocity zones revealed by receiver functions in previous geophysical studies. In the deeper parts of our velocity model we image a positive anomaly interpreted to be the heterogenous Indian lithosphere vertically descending beneath the centre of the Tibetan Platea

    Eosinophil cationic protein and interleukin-8 levels in bronchial lavage fluid from children with asthma and infantile wheeze

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    It has been shown previously that airway eosinophils characterize childhood asthma and neutrophils contribute to the pathophysiology of both infantile wheezing and asthma. Therefore, eosinophil cationic protein (ECP) and interleukin-8 (IL-8) levels in bronchoalveolar lavage fluid (BALF) from asthmatics (n = 16) and infantile wheezers (n = 30) were analyzed as markers of eosinophil- and neutrophil-mediated inflammation. To aid the interpretation, a control group of children (n = 10) with no lower airway pathology were included. Disease severity was assessed by using a symptom score. Surprisingly, no significant difference was found in IL-8 or ECP levels among asthma, infantile wheeze, and control groups. Asthma was characterized by: a correlation between ECP levels and eosinophil counts (r = 0.618, p = 0.014); a correlation between neutrophil number and IL-8 levels (r = 0.747, p = 0.002); and increasing IL-8 levels with symptom score (p = 0.03). In infantile wheezers, IL-8 levels were poorly related to neutrophil number but were significantly increased when neutrophils were > 10%. Although detectable levels were found in all but one symptomatic infant, IL-8 concentrations did not reflect the symptom score in infantile wheeze. ECP was unexpectedly correlated to neutrophil percentages (Rho = 0.832, p = 0.001), and a threshold of ECP > 20 ng/ml was associated with persistent symptoms in these infantile wheezers. Hence, in accordance with BALF cellularity, activation of eosinophils was suggested by raised levels of ECP in childhood asthma, but not in infantile wheeze. Neutrophil-mediated inflammation appeared to better reflect the severity of asthma than that of infantile wheeze. Although its meaning remains to be elucidated, ECP was suggested to be a helpful indicator of persistent infantile wheeze. However, its utility as a marker predicting ongoing asthma remains to be established
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