899 resultados para iconographics sources


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The aim of this paper is to provide a review of general processes related to plasma sources, their transport, energization, and losses in the planetary magnetospheres. We provide background information as well as the most up-to-date knowledge of the comparative studies of planetary magnetospheres, with a focus on the plasma supply to each region of the magnetospheres. This review also includes the basic equations and modeling methods commonly used to simulate the plasma sources of the planetary magnetospheres. In this paper, we will describe basic and common processes related to plasma supply to each region of the planetary magnetospheres in our solar system. First, we will describe source processes in Sect. 1. Then the transport and energization processes to supply those source plasmas to various regions of the magnetosphere are described in Sect. 2. Loss processes are also important to understand the plasma population in the magnetosphere and Sect. 3 is dedicated to the explanation of the loss processes. In Sect. 4, we also briefly summarize the basic equations and modeling methods with a focus on plasma supply processes for planetary magnetospheres.

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We measured carbon, nitrogen, protein, bacterial and microalgal abundance, and mineral-specific surface area in sediments from the feeding zone of undisturbed Saccoglossus kowalewskyi, as well as in their fresh egesta. Comparison of results using surficial material 1 mm) and the top 3 mm of sediments indicated ingestion of surficial material by the enteropneusts. Assuming the surficial sediment as a food source results in apparent absorption efficiencies of 15% for TOC, 35% for TON, 60% for protein and 86% for microalgae. The C:N ratio of the apparently absorbed material was 4.2, consistent with an amino acid-rich diet. Protein- nitrogen uptake, however, accounted for only about 28% of total nitrogen absorption, indicating a dominant use of non-protein nitrogen . Bacterial and microalgal contributions to dietary nitrogen uptake were no more than 3% and 4% respectively. Active worms maintain 2 foraging areas with an average total foraging volume of 0.9 cm3 and a volume ingestion rate of 0.06 to 0.12 cm3 ind.-1 h-1. If the preferred feeding zone of these enteropneusts is the nitrogen -enriched surficial layer, we estimate that their feeding activities will deplete the available food resources every 8 to 16 h and they may rely on biological and tidal redistribution of surface material.

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There is a lack of plant response to fertilizer K in some sandy soils even though routine soil tests for soil available K are shown to be low. This lack of plant response to K fertilizer application may be explained by K release from nonexchangeable forms. Greenhouse and laboratory experiments were conducted to evaluate (a) response of bentgrass (Agrostis palustris [Agrostis stolonifera var. palustris]) cv. Pencross grown in rootzones with different sand sources to K fertilizer application and (b) K release from nonexchangeable forms from the different sand sources as an index to K availability. Experimental variables in the greenhouse were 2 K levels (0 and 250 mg K/kg soil) and 8 sand rootzone sources. Rootzone soils were sub-irrigated to ensure no K loss from leaching. Two laboratory methods (boiling 1 M HNO3 extraction and continuous leaching with 0.01 M HCl) and total K uptake by the bentgrass were employed to index K release from nonexchangeable forms for each rootzone source. K fertilizer application significantly increased bentgrass yield growing in one rootzone source and root weight in 3 rootzone sources. K uptake by bentgrass and the 2 laboratory methods showed important differences in K release from the sand rootzones. The K removed by the 2 laboratory methods was closely related to leaf tissue K and K uptake, with the 1 M HNO3 extraction method providing the closest fit. The release of K from primary minerals in some rootzones with high sand content is proceeding at rates to satisfy bentgrass requirements for K. The 1 M HNO3 extraction method may provide an alternative to the routine laboratory procedures presently being used to measure the extractable K in sand-based constructed putting greens by measuring K contributed by nonexchangeable forms.

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by Howard Hensman

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To determine the association of food sources of calcium with weight class in adolescent girls, the major food sources of calcium were determined for 718 sixth grade girls at three different time periods during an 18 month school-based health intervention program using a FFQ. To determine weight class, the BMI of each girl was stratified using CDC age and gender specific criteria at each time period. The percent contribution of the major food sources of calcium to total calcium intake was compared among the different weight classes at each time period, among those girls who had changed weight class at the different time periods and for those girls who did not change weight class at the different time periods. The mean total calcium intake increased by 20% between the first two time periods and by 12% between the first and last time periods with the intervention despite baseline total calcium intake already being greater than the recommended 1300 mg/day. The percent contribution of the major food sources of calcium were highly correlated among the weight classes that were compared throughout the study. Those girls who remained in the normal weight class throughout the study had the most consistent intake of food sources of calcium. Their top four food sources of calcium were different types of milk which provided greater than 50% of their total calcium intake. Despite there being no significant differences in the major food sources of calcium among the different weight classes, these data show a successful intervention for increasing calcium intake among adolescent girls. ^

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When compared to other types of occupational injuries, radiation overexposure events are somewhat rare, so health care providers may not be familiar with the actual clinical care to be provided when such an event occurs. Radiation overexposure treatment decisions are predicated on the amount of radiation dose received, which is a value many health care providers may not have the knowledge or expertise to either calculate or even estimate. Even the different units of measure for radiation exposure and dose received can be a source of confusion. The prompt treatment of radiation overexposure victims could be enhanced and facilitated through the creation of a single, simple protocol that consists of the various means of dose measurement and estimation, correlated to the corresponding appropriate clinical care measures. This culminating experience will assemble essential information currently maintained in disparate references to create a single, simplified protocol to facilitate the treatment of victims of acute external radiation overexposure. ^

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Non routine hospital settings are those that are infrequently used in hospitals and that often do not come to mind when sanitation and disinfection practices are used. These settings are a major source of nosocomial, or hospital acquired, infections, and are often overlooked. Data on these sources are often scattered and scarce, but these sources are significant such that they warrant equal attention of commonly recognized nosocomial infection sources in order to help reduce incidence of nosocomial infections. ^

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The occurrence of waste pharmaceuticals has been identified and well documented in water sources throughout North America and Europe. Many studies have been conducted which identify the occurrence of various pharmaceutical compounds in these waters. This project is an extensive review of the documented evidence of this occurrence published in the scientific literature. This review was performed to determine if this occurrence has a significant impact on the environment and public health. This project and review found that pharmaceuticals such as sex hormone drugs, antibiotic drugs and antineoplastic/cytostatic agents as well as their metabolites have been found to occur in water sources throughout the United States at levels high enough to have noticeable impacts on human health and the environment. It was determined that the primary sources of this occurrence of pharmaceuticals were waste water effluent and solid wastes from sewage treatment plants, pharmaceutical manufacturing plants, healthcare and biomedical research facilities, as well as runoff from veterinary medicine applications (including aquaculture). ^ In addition, current public policies of US governmental agencies such as the Environmental Protection Agency (EPA), Food and Drug Administration (FDA), and Drug Enforcement Agency (DEA) have been evaluated to see if they are doing a sufficient job at controlling this issue. Specific recommendations for developing these EPA, FDA, and DEA policies have been made to mitigate, prevent, or eliminate this issue.^ Other possible interventions such as implementing engineering controls were also evaluated in order to mitigate, prevent and eliminate this issue. These engineering controls include implementing improved current treatment technologies such as the advancement and improvement of waste water treatment processes utilized by conventional sewage treatment and pharmaceutical manufacturing plants. In addition, administrative controls such as the use of “green chemistry” in drug synthesis and design were also explored and evaluated as possible alternatives to mitigate, prevent, or eliminate this issue. Specific recommendations for incorporating these engineering and administrative controls into the applicable EPA, FDA, and DEA policies have also been made.^

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Breast and cervical cancer, though less common in Mexican-American than in Anglo women, are more likely to go undetected in Mexican-American women, leaving them more vulnerable to advanced disease and death. Although highly effective screening tests--the Pap smear and the mammogram--can detect these cancers early, many Mexican-American women do not regularly undergo these preventive screening tests.^ To explore the differential influence of encouraging sources of health information, this investigation examined the relationship between encouragement from a "peer"--husband or partner, child or children, other family members, or close friends--and a "health professional"--a doctor, a nurse, or another health professional--on Mexican-American women's cancer screening intentions and behaviors. Furthermore, this research explored whether the sources' influence on cancer screening intentions and behaviors differed depending on level of acculturation.^ One thousand seven hundred eleven surveys of Mexican-American women were analyzed to identify the source that most effectively encourages these women to participate in cancer screening. The data provided evidence that health professionals strongly influenced this population's cancer screening intentions and behaviors. Evidence for peer influence was also found; however, it was usually weaker, and, in some cases, negligible. Peer encouragement was related to Pap test behaviors and mammogram intentions, but not to Pap test intentions or mammogram behaviors. Consistently, women reported greater intentions and screening behaviors when encouraged from a health professional than from a peer. Acculturation was not found to be a modifying variable related to the relationship between sources of information and Pap test or mammogram intentions and behaviors.^ Because health professionals were identified as strongly influencing both intentions and behaviors for Pap tests and mammograms, further efforts should be undertaken to urge them to encourage their clients to obtain cancer screening. Failure to provide this encouragement leads to missed opportunities. Enlisting support from peers also may help to increase cancer screening participation in urban Mexican-American women; however, the consistently greater intentions and behaviors related to a health professional's encouragement indicated the greater power of the latter. ^

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The geographic distribution of average annual age-adjusted mortality rates (1964-1976) for four types of cancer (all cancer sites combined, gastrointestinal, urinary, and lung cancer) were compared by sources of drinking water for 254 Texas counties and county rural areas and 301 Texas cities. Exposure variables considered were surface versus ground water, public water supplies versus individuals wells, and trihalomethane levels in municipal water supplies. Each general source of "surface" and "ground" water was further divided by aggregating ground water using areas by aquifers and surface water using study areas by river basins. Potential confounding variables taken into account included median education, employment in cancer risk industries, population mobility, ethnicity, and urbanicity. A pattern of higher and lower cancer mortality rates was found for populations using some aquifers and river basins. Further study is required to determine whether the differences in cancer mortality rates that were observed are related to drinking water content or are coincidental with differences in personal characteristics which could not be taken into account in this ecologic study design. ^

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With continuous new improvements in brachytherapy source designs and techniques, method of 3D dosimetry for treatment dose verifications would better ensure accurate patient radiotherapy treatment. This study was aimed to first evaluate the 3D dose distributions of the low-dose rate (LDR) Amersham 6711 OncoseedTM using PRESAGE® dosimeters to establish PRESAGE® as a suitable brachytherapy dosimeter. The new AgX100 125I seed model (Theragenics Corporation) was then characterized using PRESAGE® following the TG-43 protocol. PRESAGE® dosimeters are solid, polyurethane-based, 3D dosimeters doped with radiochromic leuco dyes that produce a linear optical density response to radiation dose. For this project, the radiochromic response in PRESAGE® was captured using optical-CT scanning (632 nm) and the final 3D dose matrix was reconstructed using the MATLAB software. An Amersham 6711 seed with an air-kerma strength of approximately 9 U was used to irradiate two dosimeters to 2 Gy and 11 Gy at 1 cm to evaluate dose rates in the r=1 cm to r=5 cm region. The dosimetry parameters were compared to the values published in the updated AAPM Report No. 51 (TG-43U1). An AgX100 seed with an air-kerma strength of about 6 U was used to irradiate two dosimeters to 3.6 Gy and 12.5 Gy at 1 cm. The dosimetry parameters for the AgX100 were compared to the values measured from previous Monte-Carlo and experimental studies. In general, the measured dose rate constant, anisotropy function, and radial dose function for the Amersham 6711 showed agreements better than 5% compared to consensus values in the r=1 to r=3 cm region. The dose rates and radial dose functions measured for the AgX100 agreed with the MCNPX and TLD-measured values within 3% in the r=1 to r=3 cm region. The measured anisotropy function in PRESAGE® showed relative differences of up to 9% with the MCNPX calculated values. It was determined that post-irradiation optical density change over several days was non-linear in different dose regions, and therefore the dose values in the r=4 to r=5 cm regions had higher uncertainty due to this effect. This study demonstrated that within the radial distance of 3 cm, brachytherapy dosimetry in PRESAGE® can be accurate within 5% as long as irradiation times are within 48 hours.