527 research outputs found
Computer simulation of carbonate platform and basin systems
The carbonate platform depositional system is sensitive to many variables, a number of which are interrelated, making it difficult to clarify how each variable affects the growth pattern of a carbonate platform. A simple computer model that simulates the carbonate platform depositional system provides an efficient means of overcoming this problem. Individual variables, such as rates of sediment production and erosion, subsidence, and eustatic sea-level cycles, are changed progressively, whereas all other variables are held constant. Changes in relative sea level (a combination of oscillatory eustatic changes, tectonic subsidence, and sediment loading) appear to exert the strongest control on the growth of carbonate platforms by determining how much sediment can accumulate on the platform top, which to some degree (along with the rate of sediment removal) influences how much sediment is available for progradation of the platform. This quantitative forward-modeling approach provides a valuable learning tool and facilitates a precise understanding of a complicated system. A forward model, such as the one presented here, can provide a basis for creating an inverse model, which can be used to constrain the variables (sediment production rate, subsidence curve, and sea-level history) that led to the cross-sectional geometry observed in the field or in a seismic section
Computer simulation of carbonate platform and basin systems
The carbonate platform depositional system is sensitive to many variables, a number of which are interrelated, making it difficult to clarify how each variable affects the growth pattern of a carbonate platform. A simple computer model that simulates the carbonate platform depositional system provides an efficient means of overcoming this problem. Individual variables, such as rates of sediment production and erosion, subsidence, and eustatic sea-level cycles, are changed progressively, whereas all other variables are held constant. Changes in relative sea level (a combination of oscillatory eustatic changes, tectonic subsidence, and sediment loading) appear to exert the strongest control on the growth of carbonate platforms by determining how much sediment can accumulate on the platform top, which to some degree (along with the rate of sediment removal) influences how much sediment is available for progradation of the platform. This quantitative forward-modeling approach provides a valuable learning tool and facilitates a precise understanding of a complicated system. A forward model, such as the one presented here, can provide a basis for creating an inverse model, which can be used to constrain the variables (sediment production rate, subsidence curve, and sea-level history) that led to the cross-sectional geometry observed in the field or in a seismic section
Differential Relationship between Physical Activity and Intake of Added Sugar and Nutrient-Dense Foods: A Cross-Sectional Analysis
A curvilinear relationship exists between physical activity (PA) and dietary energy intake (EI), which is reduced in moderately active when compared to inactive and highly active individuals, but the impact of PA on eating patterns remains poorly understood. Our goal was to establish the relationship between PA and intake of foods with varying energy and nutrient density. Data from the 2009–2010 United States National Health and Nutrition Examination Survey were used to include a Dietary Screener Questionnaire for estimated intakes of added sugar, fruits and vegetables, whole grains, fiber, and dairy. Participants (n = 4766; 49.7% women) were divided into sex-specific quintiles based on their habitual PA. After adjustment for age, body mass index, household income, and education, intakes were compared between PA quartiles, using the lowest activity quintile (Q1) as reference. Women in the second to fourth quintile (Q2-Q4) consumed less added sugar from sugary foods (+2 tsp/day) and from sweetened beverages (+2 tsp/day; all p \u3c 0.05 vs. Q1). In men, added sugar intake was elevated in the highest activity quintile (Q5: +3 ± 1 tsp/day, p = 0.007 vs. Q1). Fruit and vegetable intake increased (women: Q1-Q4 +0.3 ± 0.1 cup eq/day; p \u3c 0.001; men: Q1-Q3 +0.3 ± 0.1 cup eq/day, p = 0.002) and stagnated in higher quintiles. Dairy intake increased with PA only in men (Q5: +0.3 ± 0.1 cup eq/day, p \u3c 0.001 vs. Q1). Results demonstrate a differential relationship between habitual PA and dietary intakes, whereby moderate but not necessarily highest PA levels are associated with reduced added sugar and increased nutrient-dense food consumption. Future research should examine specific mechanisms of food choices at various PA levels to ensure dietary behaviors (i.e., increased sugary food intake) do not negate positive effects of PA
Australian health policy on access to medical care for refugees and asylum seekers
Since the tightening of Australian policy for protection visa applicants began in the 1990s, access to health care has been increasingly restricted to asylum seekers on a range of different visa types. This paper summarises those legislative changes and discusses their implications for health policy relating to refugees and asylum seekers in Australia. Of particular concern are asylum seekers on Bridging Visas with no work rights and no access to Medicare. The paper examines several key questions: What is the current state of play, in terms of health screening and medical care policies, for asylum seekers and refugees? Relatedly, how has current policy changed from that of the past? How does Australia compare with other countries in relation to health policy for asylum seekers and refugees? These questions are addressed with the aim of providing a clear description of the current situation concerning Australian health policy on access to medical care for asylum seekers and refugees. Issues concerning lack of access to appropriate health care and related services are raised, ethical and practical issues are explored, and current policy gaps are investigated
Visual, Optical and Replica Inspections: Surface Preparation of 650 MHz NB Cavity for PIP-II Linac
Surface preparation of niobium superconducting RF cavities is a critical step
for achieving good RF performance under the superconducting state. Surface
defect, roughness, and contamination affect the accelerating gradient and
quality factor of the cavities. We report surface inspection methods used to
control the surface processing of 650 MHz cavities designated for the
pre-production and prototype cryomodules for PIP-II linac. The cavity surface
was routinely inspected visually, with an optical camera, and by microscopic
scanning of surface replicas. This article covers details on the surface
inspection methods and surface polishing process used to repair the surface
Differential Relationship between Physical Activity and Intake of Added Sugar and Nutrient-Dense Foods: A Cross-Sectional Analysis
A curvilinear relationship exists between physical activity (PA) and dietary energy intake (EI), which is reduced in moderately active when compared to inactive and highly active individuals, but the impact of PA on eating patterns remains poorly understood. Our goal was to establish the relationship between PA and intake of foods with varying energy and nutrient density. Data from the 2009–2010 United States National Health and Nutrition Examination Survey were used to include a Dietary Screener Questionnaire for estimated intakes of added sugar, fruits and vegetables, whole grains, fiber, and dairy. Participants (n = 4766; 49.7% women) were divided into sex-specific quintiles based on their habitual PA. After adjustment for age, body mass index, household income, and education, intakes were compared between PA quartiles, using the lowest activity quintile (Q1) as reference. Women in the second to fourth quintile (Q2-Q4) consumed less added sugar from sugary foods (+2 tsp/day) and from sweetened beverages (+2 tsp/day; all p \u3c 0.05 vs. Q1). In men, added sugar intake was elevated in the highest activity quintile (Q5: +3 ± 1 tsp/day, p = 0.007 vs. Q1). Fruit and vegetable intake increased (women: Q1-Q4 +0.3 ± 0.1 cup eq/day; p \u3c 0.001; men: Q1-Q3 +0.3 ± 0.1 cup eq/day, p = 0.002) and stagnated in higher quintiles. Dairy intake increased with PA only in men (Q5: +0.3 ± 0.1 cup eq/day, p \u3c 0.001 vs. Q1). Results demonstrate a differential relationship between habitual PA and dietary intakes, whereby moderate but not necessarily highest PA levels are associated with reduced added sugar and increased nutrient-dense food consumption. Future research should examine specific mechanisms of food choices at various PA levels to ensure dietary behaviors (i.e., increased sugary food intake) do not negate positive effects of PA
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