61 research outputs found

    Intra-Crater Eruption Dynamics at Nyiragongo (D.R. Congo), 2002–2021

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    Nyiragongo is one of the rare volcanoes on Earth hosting a lava lake. However, the understanding of its plumbing and lava lake systems remains limited, with, until recently, only sporadic or time-limited historical observations and measurements. Combining dense accurate lava lake and crater floor level measurements based on 1,703 satellite radar images and topographic reconstructions using photogrammetry, we obtain the first reliable picture and time evolution of intra-crater erupted lava volumes between the two last flank eruptions in January 2002 and May 2021. The filling of the crater by lava, initiated in 2002 and continued up to May 2021, is seen as an evidence of a long-term pressure build up of the magmatic system. This filling occurs through irregular pulsatory episodes of rising lava lake level, some of which overflow and solidify on the surrounding crater floor. Pauses of stable molten lava lake level and sudden numerous level drops also marked the summit's eruptive activity. The joint analysis with seismic records available since 2015 revealed that the largest lava lake drops are synchronous with seismic swarms associated with deep magma intrusions, generally preceded by an increase of extrusion rate within the crater. The appearance of a spatter cone in the summit crater in 2016, most likely superficially branched to the lava lake, was a clear marker of the change in eruption dynamics. This first long-term time series of Nyiragongo's crater topography between two hazardous flank eruptions might further help to better decipher Nyiragongo's past and future behavior using multi-parameter observations

    Role of flow cytometry immunophenotyping in the diagnosis of leptomeningeal carcinomatosis

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    PURPOSE: To explore the contribution of flow cytometry immunophenotyping (FCI) in detecting leptomeningeal disease in patients with solid tumors. EXPERIMENTAL DESIGN: Cerebrospinal fluid (CSF) samples from 78 patients who received a diagnosis of epithelial-cell solid tumors and had clinical data suggestive of leptomeningeal carcinomatosis (LC) were studied. A novel FCI protocol was used to identify cells expressing the epithelial cell antigen EpCAM and their DNA content. Accompanying inflammatory cells were also described. FCI results (positive or negative for malignancy) were compared with those from CSF cytology and with the diagnosis established by the clinicians: patients with LC (n = 49), without LC (n = 26), and undetermined (n = 3). RESULTS: FCI described a wide range of EpCAM-positive cells with a hyperdiploid DNA content in the CSF of patients with LC. Compared with cytology, FCI showed higher sensitivity (75.5 vs 65.3) and negative predictive value (67.6 vs 60.5), and similar specificity (96.1 vs 100) and positive predictive value (97.4 vs 100). Concordance between cytology and FCI was high (Kp = 0.83), although misdiagnosis of LC did not show differences between evaluating the CSF with 1 or 2 techniques (P = .06). Receiver-operator characteristic curve analyses showed that lymphocytes and monocytes had a different distribution between patients with and without LC. CONCLUSION: FCI seems to be a promising new tool for improving the diagnostic examination of patients with suspicion of LC. Detection of epithelial cells with a higher DNA content is highly specific of LC, but evaluation of the nonepithelial cell compartment of the CSF might also be useful for supporting this diagnosis

    Naive and memory CD4+ T-cells in the cerebrospinal fluid of children with aseptic meningitis following measles-mumps-rubella vaccination and enteroviral meningitis

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    We investigated the distribution of memory (CD45RO+) and naive (CD45RA+CD62L+) CD4+ T-cells as well as CD8+ T-cells and total T-cells in the CSF of children with aseptic meningitis following measles-mumps-rubella (MMW) vaccination and those with enteroviral meningitis. Flow cytometric analysis of CSF cells was performed in 12 children with MMR vaccine-associated meningitis and 11 children with enteroviral meningitis. Percentages of total T-cells, CD4+ and CD8+ T-cells and monocytes in CSF of patients from the two groups were not significantly different. The majority of CD4+ T-cells in the CSF of both patient groups were of memory phenotype. Percentages of CSF naive CD4+ T-cells were increased in children with aseptic meningitis following MMR vaccination. Further studies focused on the more detailed immunophenotyping of CSF cells are needed to fully establish the usefulness of flow cytometry in the diagnostic workup of inflammatory CNS diseases in children

    The Development of Occupational Aspirations and Expectations among Inner-City Boys

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    The occupational aspirations and expectations of two populations of boys in grades 2, 4, 6, and 8 were examined in order (1) to describe what is unique about the development of job preferences among urban ghetto children who live in settings where many adult males are not well attached to the labor force and (2) to examine 6 reasons for any age- and population-dependent patterns there might be in job aspirations and job expectations. Findings show that boys tend to be more realistic about occupational aspirations and expectations the older they are; that from second grade on the occupational expectations of inner-city boys mirror existing race and class differences in adult job holdings; that the gap between occupational aspirations and expectations is greater for the ghetto boys and remains roughly constant in size across the grades examined; and that the lower occupational expectations of the inner-city boys are strongly related to their lower educational expectations, with these educational expectations being associated with fewer poor boys having a biological father at home and with more of these boys seeing obstacles to success in the local social setting. But, the lower occupational expectations of the ghetto boys are not due to having fewer positive role models or believing that schooling will not pay off for them in the future as it does for others
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