Triggering and modulation of geyser eruptions in Yellowstone National Park by earthquakes, earth tides, and weather

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 119 (2014): 1718–1737, doi:10.1002/2013JB010803.We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful geysers in Yellowstone National Park. We focus our statistical analysis on the response of these geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs of these geysers are insensitive to periodic stresses induced by solid earth tides and barometric pressure variations; (2) Daisy (pool geyser) IBEs lengthen by evaporation and heat loss in response to large wind storms and cold air; and (3) Old Faithful (cone geyser) IBEs are not modulated by air temperature and pressure variations, wind, and precipitation, suggesting that the subsurface water column is decoupled from the atmosphere. Dynamic stress changes of 0.1−0.2 MPa resulting from the 2002 M-7.9 Denali, Alaska, earthquake surface waves caused a statistically significant shortening of Daisy geyser's IBEs. Stresses induced by other large global earthquakes during the study period were at least an order of magnitude smaller. In contrast, dynamic stresses of >0.5 MPa from three large regional earthquakes in 1959, 1975, and 1983 caused lengthening of Old Faithful's IBEs. We infer that most subannual geyser IBE variability is dominated by internal processes and interaction with other geysers. The results of this study provide quantitative bounds on the sensitivity of hydrothermal systems to external stress perturbations and have implications for studying the triggering and modulation of volcanic eruptions by external forces.K. Luttrell and S. Hurwitz were supported by the USGS Volcano Hazards Program, and Michael Manga was supported by NSF grant EAR1114184.2014-09-0

Triggering and modulation of geyser eruptions in Yellowstone National Park by earthquakes, earth tides, and weather

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 119 (2014): 1718–1737, doi:10.1002/2013JB010803.We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful geysers in Yellowstone National Park. We focus our statistical analysis on the response of these geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs of these geysers are insensitive to periodic stresses induced by solid earth tides and barometric pressure variations; (2) Daisy (pool geyser) IBEs lengthen by evaporation and heat loss in response to large wind storms and cold air; and (3) Old Faithful (cone geyser) IBEs are not modulated by air temperature and pressure variations, wind, and precipitation, suggesting that the subsurface water column is decoupled from the atmosphere. Dynamic stress changes of 0.1−0.2 MPa resulting from the 2002 M-7.9 Denali, Alaska, earthquake surface waves caused a statistically significant shortening of Daisy geyser's IBEs. Stresses induced by other large global earthquakes during the study period were at least an order of magnitude smaller. In contrast, dynamic stresses of >0.5 MPa from three large regional earthquakes in 1959, 1975, and 1983 caused lengthening of Old Faithful's IBEs. We infer that most subannual geyser IBE variability is dominated by internal processes and interaction with other geysers. The results of this study provide quantitative bounds on the sensitivity of hydrothermal systems to external stress perturbations and have implications for studying the triggering and modulation of volcanic eruptions by external forces.K. Luttrell and S. Hurwitz were supported by the USGS Volcano Hazards Program, and Michael Manga was supported by NSF grant EAR1114184.2014-09-0

Assessment of agro-ecological influence on the seed quality of groundnut (Arachis hypogaea) in The Gambia

A survey was conducted to assess the quality of groundnut seed produced and stored under ambient environment across various agro-ecologies of The Gambia, with a view to understanding regions with comparative advantage for its production and storage. Seed production activities of 60 seed growers in 26 communities were collected using structured questionnaires, interviews and observations. The Global Positioning System (GPS) coordinates of the communities were geo-referenced to identify the geographical positioning of the production sites. Samples of the groundnut pods were taken from the seed stores, threshed and subjected to seed quality analysis. Descriptive analysis was used to categorize the seed sources, hectarage cultivated, while seed quality data were subjected to analysis of variance of Nested Design. Means of significant factors were separated using Duncan Multiple Range Test (DMRT) at 5% significant level. The study showed that groundnut seed production is better concentrated in regions with optimum and sustainable rainfall that will reduce abiotic stress during seed development like the Lower River Region, West Coast Region and Central River Region. Fleur-11 variety was identified as one of the most promising varieties for groundnut cultivation in The Gambia and Tropical Africa

Association of intestinal helminthic infection and nutritional status of primary school children in Gombe State, Nigeria

Background: Intestinal helminthic infections are among the commonest infections worldwide. It often affects the poorest communities and has similar geographic distribution with malnutrition. Intestinal helminthic infection contributes to undernutrition through subtle reduction in digestion and absorption of food, chronic inflammation and loss of nutrients. The objective of this study is to determine the prevalence of intestinal helminthic infection and its relationship with nutritional status of primary school children in Gombe, Gombe State, Nigeria. Methodology: This was a cross sectional study of 350 pupils selected through multistage random sampling technique from 24 primary schools in Gombe, Gombe State, Nigeria from July 2018 to January 2019. Demographic information including age, gender, height, and weight were collected from each participant with a designed collection form. The data were analysed using SPSS version 24.0, and presented as frequency distribution and mean ± SD. The Chi-square test (with Odds ratio and 95% confidence interval) was used to test for association between prevalence of helminthiasis and factors such as gender, age group and school type. A p value of less than 0.05 was considered statistically significant at 95% confidence interval. Results: The prevalence of intestinal helminthic infection was 23.7% (83/350). Eighty (96.4%) of the 83 infected pupils were in public schools while only 3 (3.6%) were in private schools (p<0.001). The prevalence of helminthiasis was significantly higher in underweight pupils (34%, OR=2.113, p=0.0065)) and significantly lower (5.4%, OR=0.1637, p=0.0037) in overweight pupils while the prevalence was not significantly associated with normal weight (p=0.5482) or obesity (p=1.000). Conclusions: Intestinal helminthic infection is a public health problem in children with adverse significant relationship with nutritional status. Provision of toilet facilities in schools and periodic de-worming of pupils aimed at reducing loss of nutrients from intestinal helminthiasis are recommended

Alloantibodies, Anti-D, Childbearing age, Women, Cameroon

We conducted a cross sectional retrospective study to determine anti-D and D-negative phenotype rates among Cameroonian women of reproductive age (15 – 44 years), in order to evaluate the importance ofD alloimmunization. Analysis of the haematology laboratory records from January 2006 to December 2007 harvested 225 results for red blood cell alloantibody screening and 2460 D phenotypes. Anti-D rate was found to be high at 4% and not linked to women’s parity. Three hundred and fifty two (14.3%) women were found to be D-negative. Anti-D rates significantly decreased with age from 18.8% among teenagers (15-19) to 7.8% among older women (35-44) (p = 0.001). The number of women submitted to both irregular antibody screening and type D phenotype determination was not strong enough (50) to analyse the link between anti-D rate and antigen D distribution in our study (Afr J Reprod Health 2009; 13[3]:47-52)

Epilepsy in rural South African children prevalence, associated disability and management

Objective. To determine the prevalence of epilepsy and its associated disabilities in rural South African children aged 2 - 9 years.Setting. Eight villages in the district of Bushbuckridge, Northern Province, South Africa_Design. A two-phase design was used_ The first phase involved screening children on a house-to-house baSis by interviewing mothers or caregivers using an internationally validated questionnaire for detecting childhood disability in developing countries. The second phase consisted of a paediatric/ neurodevelopmental assessment of the children who screened positive.Results. A total of 6692 children were screened; 722 (10.8%) had a paediatric evaluation and 49 (0.73%) had epilepsy. The· lifetime and active prevalences of epilepsy in these children were 7.3/1 000 and 6.7/1 000 respectively. Associated developmental disability was recorded in 35 affected children (71.4%), including 8 (16.3%) in whom this was moderate to severe. More than a half of the children with epilepsy (57.1%) did not receive anticonvulsant medication.Conclusion. The prevalence of epilepsy in the rural childhood population investigated is higher than that recorded in most similar studies from sub-Saharan Africa, and the poor utilisation of 'appropriate anticonvulsant treatment is cause for concern. This study highlights the paucity of relevant information on the epidemiology of epilepsy in South Africa and that the system available for its management, especially in rural areas, appears to have functional deficiencies. Appropriate research is needed to identify the problems in service delivery and to enable the planning and implementation of an appropriate primary health care-based system for the diagnosis and management of epilepsy in children