5 results
Search Results
2. Deep low velocity layer in the sublithospheric mantle beneath India.
- Author
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Kumar, M Ravi, Singh, Arun, and Saikia, Dipankar
- Subjects
SLABS (Structural geology) ,MELTWATER ,MANTLE plumes ,DISCONTINUITIES (Geology) ,BODY composition - Abstract
Globally, there is now a growing evidence for a low velocity layer in the deeper parts of the upper mantle, above the 410 km discontinuity (hereafter called LVL-410). The origin of this layer is primarily attributed to interaction of slabs or plumes with a hydrous mantle transition zone (MTZ) that results in dehydration melting induced by water transport upward out of the MTZ. However, the ubiquitous nature of this layer and its causative remain contentious. In this study, we use high quality receiver functions (RFs) sampling diverse tectonic units of the Indian subcontinent to identify Ps conversions from the LVL-410. Bootstrap and differential slowness stacking of RFs migrated to depth using a 3-D velocity model reveal unequivocal presence of a deep low velocity layer at depths varying from 290 to 400 km. This layer appears more pervasive and deeper beneath the Himalaya, where detached subducted slabs in the MTZ have been previously reported. Interestingly, the layer is shallower in plume affected regions like the Deccan Volcanic Province and Southern Granulite Terrane. Even though a common explanation does not appear currently feasible, our observations reaffirm deep low velocity layers in the bottom part of the upper mantle and add to the list of regions that show strong presence of such layers above the 410 km discontinuity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Investigating the effects of species niche shifts on the potential distribution of Tuta absoluta (Lepidoptera: Gelechiidae) by using global occurrence data.
- Author
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Yuan, Xuejiao, Zhang, Yuanyuan, Hu, Luyi, Sang, Weiguo, and Yang, Zheng
- Subjects
GELECHIIDAE ,LEPIDOPTERA ,ECOLOGICAL niche ,PRINCIPAL components analysis ,SPECIES - Abstract
Invasive species may occupy quite different environments in their invaded areas to native ones, which may intensively interfere with predicting potential distribution through ecological niche modeling (ENM). Here, we take the tomato leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), a tomato pest, as an example to investigate this topic. We analyzed niche expansion, stability, unfilling, and Schoener's D by principal component analysis (PCA) ordination method to examine its realized niche shifts and to explore how ENM approaches are affected by niche shifts. We used 5 datasets: Asian, African, European, South American, and global occurrence records in this study. Results showed that high niche unfilling for the species' invaded areas in Asia (20%), Africa (12%), and Europe (37%), possibly due to T. absoluta being in the early stages of invasion. High niche expansion was observed in Asia (38%) and Europe (19%), implying that some European and Asian populations had reached new climatic areas. African niche had the most niche stability (94%) and was equivalent to the native one in climate space (PCA ordination method), but the n -dimensional climate space framework showed that they were different. When projecting the native model to Asia and Europe, the native model performed poorly, implying that the niche shifts affected the transferability of the native model. ENM based on global data outperformed than other models, and our results suggested that T. absoluta has a large potential distribution in Asia, Mexico, South Europe, the United States, and Australia. Meanwhile, we recommend updating ENMs based on the species' invasion stage. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
4. Population Enumeration and Household Utilization Survey Methods in the Enterics for Global Health (EFGH): Shigella Surveillance Study.
- Author
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Dodd, Ryan, Awuor, Alex O, Bardales, Paul F Garcia, Khanam, Farhana, Mategula, Donnie, Onwuchekwa, Uma, Sarwar, Golam, Yousafzai, Mohammad Tahir, Ahmed, Naveed, Atlas, Hannah E, Bhuiyan, Md Amirul Islam, Colston, Josh M, Conteh, Bakary, Diawara, Manan, Dilruba, Nasrin, Elwood, Sarah, Fatima, Irum, Feutz, Erika, Galagan, Sean R, and Haque, Shahinur
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SHIGELLOSIS ,SHIGELLA ,WORLD health ,HOUSEHOLD surveys ,HEALTH facilities ,WATERSHEDS - Abstract
Background Accurate estimation of diarrhea incidence from facility-based surveillance requires estimating the population at risk and accounting for case patients who do not seek care. The Enterics for Global Health (EFGH) Shigella surveillance study will characterize population denominators and healthcare-seeking behavior proportions to calculate incidence rates of Shigella diarrhea in children aged 6–35 months across 7 sites in Africa, Asia, and Latin America. Methods The Enterics for Global Health (EFGH) Shigella surveillance study will use a hybrid surveillance design, supplementing facility-based surveillance with population-based surveys to estimate population size and the proportion of children with diarrhea brought for care at EFGH health facilities. Continuous data collection over a 24 month period captures seasonality and ensures representative sampling of the population at risk during the period of facility-based enrollments. Study catchment areas are broken into randomized clusters, each sized to be feasibly enumerated by individual field teams. Conclusions The methods presented herein aim to minimize the challenges associated with hybrid surveillance, such as poor parity between survey area coverage and facility coverage, population fluctuations, seasonal variability, and adjustments to care-seeking behavior. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
- View/download PDF
5. A Systematic Review of the Therapeutic Outcome of Mucormycosis.
- Author
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Sigera, L Shamithra M and Denning, David W
- Subjects
MUCORMYCOSIS ,AMPHOTERICIN B ,MYCOSES ,ANTIFUNGAL agents ,SURGICAL excision - Abstract
Background Mucormycosis is a potentially lethal mycosis. We reviewed peer-reviewed publications on mucormycosis to assess therapeutic outcomes. Methods A systematic literature search using the Ovid MEDLINE and EMBASE databases identified manuscripts describing human mucormycosis diagnosed according to European Organization for Research and Treatment of Cancer and the Mycoses Study Group criteria with therapeutic outcomes published from 2000 to 2022. Results In 126 articles, 10 335 patients were described, most from Asia (n = 6632, 66%). Diabetes was the most frequent underlying disease (n = 6188, 60%); 222 (2.1%) patients had no underlying diseases. The dominant clinical form was rhino-orbitocerebral (n = 7159, 69.3%), followed by pulmonary (n = 1062, 10.3%). Of 5364 patients with outcome data, amphotericin B monotherapy (n = 3749, mortality 31.5%) was most frequent, followed by amphotericin B + azole (n = 843, mortality 6.6%; P <.0001), amphotericin B followed by azole (n = 357, mortality 13.7%; P <.0001), posaconazole only (n = 250, mortality 17.2%; P <.0001), and isavuconazole only (n = 65, mortality 24.6%; P =.24). Duration and dose of antifungals varied widely. Documented outcomes from surgical resections in 149 patients found that 47 of 125 died (37.6%), compared with 16 of 24 (66.7%) patients who did not undergo surgery (P =.008). Conclusions Mucormycosis is more frequently reported in Asia than in Europe and is often linked to diabetes. Antifungal therapy, usually with surgery, is frequently effective for mucormycosis. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
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