6,465 research outputs found
Effects of Hypothetical NO\u3csub\u3ex\u3c/sub\u3e Sources in East Tennessee on the Ozone Concentrations Impacting the GSMNP
This thesis studied the effects of hypothetical NOx sources located in East Tennessee on the ozone concentrations impacting the Great Smoky Mountains National Park (GSMNP). The product of this study is a technique of assessing the potential impact of a new or modified large NOx source on ozone concentrations within a Class I area, without requiring an up-to-date detailed emissions inventory. The study evaluates the MAP-03 model as a screening tool for selecting the day to be modeled by the Urban Airshed Model (UAM) for each hypothetical source location. The four source locations selected to be studied in East Tennessee were: Chattanooga, Crossville, Knoxville, and the Tri-Cities area. The results of MAP-03 simulations were compared to UAM simulation results in determining that the MAP-03 model was effective in selecting the modeling scenarios for which the UAM would predict incremental increases of ozone in the GSMNP due to the potential source. The study also investigates the effects of using EPA default concentrations along the boundary of the modeling domain on predicted ozone concentrations within the modeling domain. It was found that the use of default boundary conditions may significantly affect ozone concentration predictions in the domain, so a technique was developed to minimize these effects by utilizing temporally varying concentrations along the boundary that were predicted during modeling scenarios
Chemokine-induced secretion of gelatinase B in primary human monocytes
Chemokines help control normal leukocyte trafficking as well as their infiltration into tissues during acute and chronic inflammation. Matrix metalloproteinases (MMPs) help support the extravasation and infiltration of leukocytes through limited proteolysis of basement membranes and matrix material. The effect of the chemokines RANTES/CCL5, MCP-1/CCL and SDF-1 /CXCL12 on secretion of the matrix metalloproteinase B and its endogenous inhibitor TIMP-1 was studied. RANTES/CCL5 and SDF-1/CXCL12 were found to induce MMP-9 secretion in primary human monocytes while TIMP-1 secretion was not affected. RANTES/CCL5 effects were mediated through CCR1 because the CCR1 antagonist BX471 was found to effectively block RANTES/CCL5-induced MMP-9 secretion
Plankton community composition, organic carbon and thorium-234 particle size distributions, and particle export in the Sargasso Sea
Measurements of plankton community composition (eight planktonic groups), particle size-fractionated (10, 20, 53, 70, and 100-μm Nitex screens) distributions of organic carbon (OC) and 234Th, and particle export of OC and 234Th are reported over a seasonal cycle (2006–2007) from the Bermuda Atlantic Time-Series (BATS) site. Results indicate a convergence of the particle size distributions of OC and 234Th during the winter-spring bloom period (January–March, 2007). The observed convergence of these particle size distributions is directly correlated to the depth-integrated abundance of autotrophic pico-eukaryotes (r = 0.97, P \u3c 0.05) and, to a lesser extent, Synechococcus (r = 0.85, P \u3c 0.14). In addition, there are positive correlations between the sediment trap flux of OC and 234Th at 150 m and the depth-integrated abundance of pico-eukaryotes (r = 0.94, P \u3c 0.06 for OC, and r = 0.98, P \u3c 0.05 for 234Th) and Synechococcus (r = 0.95, P \u3c 0.05 for OC, and r = 0.94, P \u3c 0.06 for 234Th). An implication of these observations and recent modeling studies (Richardson and Jackson, 2007) is that, although small in size, pico-plankton may influence large particle export from the surface waters of the subtropical Atlantic
Evidence of high bed net usage from a list randomization experiments in rural Gambia.
Label: BACKGROUND NlmCategory: BACKGROUND content:
Recording behaviours that have the potential to impact health
can be doubly challenging if the behaviour takes place in
private spaces that cannot be observed directly, and where
respondents answer what they think the recorder may want to
hear. Sleeping under a long-lasting insecticidal net (LLIN) is
an important intervention for malaria prevention, yet it is
difficult to gauge the extent to which coverage (how many nets
are in the community) differs from usage (how many people
actually sleep under a net). List randomization, a novel method
which partially obscures respondents' answers to sensitive
questions, was employed to estimate LLIN usage in The Gambia. -
Label: METHODS NlmCategory: METHODS content: "802
heads-of-household from 15 villages were recruited into a
randomized controlled trial assessing the effect of a housing
intervention on malaria. These houses were randomly assigned to
a housing intervention versus control, with stratification by
village so as to ensure balance between arms. From these, 125
households (63 intervention, 52 control) were randomly selected
for participation in the list randomization experiment, along
with 68 households from the same villages but which were not
part of the housing improvement study, resulting in a total of
196 households for the list randomization experiment.
Approximately half (n\xE2\x80\x89=\xE2\x80\x8997) of the 196
study participants were randomly assigned to the control group
and received a four-question list about non-sensitive
behaviours; the intervention group
(n\xE2\x80\x89=\xE2\x80\x8999) received the same list, with the
addition of one question on a sensitive behaviour: whether or
not they had used a bed net the previous night. Participants
were read the list of questions and then said how many of the
statements were true. Bed net usage was estimated by calculating
the difference in means between the number of affirmative
responses between the two groups." - Label: RESULTS NlmCategory:
RESULTS content: The mean number of affirmative responses in the
control group was 2.60 of four statements (95% confidence
interval, 95% CI 2.50-2.70), compared with 3.68 (95% CI
3.59-3.78) in the intervention group. Such difference (1.08; 95%
CI 94.9-100%) suggests near universal bed net usage. - Label:
CONCLUSIONS NlmCategory: CONCLUSIONS content: Bed net usage by
household heads in these rural villages was found to be high.
Though not entirely unexpected given other studies' estimates of
high bed net usage in the area, the list randomization method
should be further validated in an area with lower coverage
The representation of scientific research in the national curriculum and secondary school pupils’ perceptions of research, its function, usefulness and value to their lives
Young people’s views on what research is, how it is conducted and whether it is important, influences the decisions they make about their further studies and career choices. In this paper we report the analysis of questionnaire data with a particular focus on pupil perceptions of research in the sciences and of the scientific method. The questionnaire was a 25-item Likert Scale (1-5) distributed to seven collaborating schools. We received 2634 returns from pupils across key stages 3, 4 and 5. We also asked teachers to complete the questionnaire in order to explore how they thought their pupils would respond. We received 54 teacher responses. Statistically significant differences in the responses were identified through a chi-square test on SPSS. As what is being taught influences secondary pupil views on research we also consider how the term ‘research’ appears in the national curriculum for England and Wales and the three main English exam boards. The main theoretical construct that informs our analysis of the questionnaire data and the national curriculum is Angela Brew’s 4-tier descriptor of perceptions of research (domino, trading, layer, journey). We use this framework in order to map what, when and how research is presented to school pupils in England and Wales. We also use this framework in order to highlight and discuss certain pupil views that emerged from the questionnaire data and which indicate areas where curriculum and pedagogy intervention may be necessary: pupils seem less confident in their understanding of research as involving the identification of a research question; and, they often see research as a means to confirm one’s own opinion. They do however understand research as involving the generation of new knowledge and the collection of new data, such as interviews and questionnaires as well as laboratory work, field trips and library searches and they appear relatively confident in their statements about their ability to do research, their school experiences of research and the importance of research in their future career choice
HopScotch - a low-power renewable energy base station network for rural broadband access
The provision of adequate broadband access to communities in sparsely populated rural areas has in the past been severely restricted. In this paper, we present a wireless broadband access test bed running in the Scottish Highlands and Islands which is based on a relay network of low-power base stations. Base stations are powered by a combination of renewable sources creating a low cost and scalable solution suitable for community ownership. The use of the 5~GHz bands allows the network to offer large data rates and the testing of ultra high frequency ``white space'' bands allow expansive coverage whilst reducing the number of base stations or required transmission power. We argue that the reliance on renewable power and the intelligent use of frequency bands makes this approach an economic green radio technology which can address the problem of rural broadband access
Cerebrospinal fluid neopterin: an informative biomarker of central nervous system immune activation in HIV-1 infection
HIV-1 invades the central nervous system (CNS) in the context of acute infection, persists thereafter in the absence of treatment, and leads to chronic intrathecal immunoactivation that can be measured by the macrophage activation marker, neopterin, in cerebrospinal fluid (CSF). In this review we describe our experience with CSF neopterin measurements in 382 untreated HIV-infected patients across the spectrum of immunosuppression and HIV-related neurological diseases, in 73 untreated AIDS patients with opportunistic CNS infections, and in 233 treated patients
Effect of antiretroviral treatment on blood-brain barrier integrity in HIV-1 infection
Background Blood-brain barrier (BBB) injury is prevalent in patients with HIV-associated dementia (HAD) and is a frequent feature of HIV encephalitis. Signs of BBB damage are also sometimes found in neuroasymptomatic HIV-infected individuals without antiretroviral therapy (ART). The aim of this study was to investigate the integrity of the BBB before and after initiation of ART in both neuroasymptomatic HIV infection and in patients with HAD. Methods We determined BBB integrity by measuring cerebrospinal fluid (CSF)/plasma albumin ratios in archived CSF samples prior to and after initiation of ART in longitudinally-followed neuroasymptomatic HIV-1-infected individuals and patients with HAD. We also analyzed HIV RNA in blood and CSF, IgG Index, CSF WBC counts, and CSF concentrations of beta 2-micoglobulin, neopterin, and neurofilament light chain protein (NfL). Results We included 159 HIV-infected participants; 82 neuroasymptomatic individuals and 77 with HAD. All neuroasymptomatic individuals (82/82), and 10/77 individuals with HAD, were longitudinally followed with a median (interquartile range, IQR) follow-up of 758 (230-1752) days for the neuroasymptomatic individuals, and a median (IQR) follow-up of 241 (50-994) days for the individuals with HAD. Twelve percent (10/82) of the neuroasymptomatic individuals and 80% (8/10) of the longitudinally-followed individuals with HAD had elevated albumin ratios at baseline. At the last follow-up, 9% (7/82) of the neuroasymptomatic individuals and 20% (2/10) of the individuals with HAD had elevated albumin ratios. ART significantly decreased albumin ratios in both neuroasymptomatic individuals and in patients with HAD. Conclusion These findings indicate that ART improves and possibly normalizes BBB integrity in both neuroasymptomatic HIV-infected individuals and in patients with HAD
Immobilisation of Higher Activity Wastes from Nuclear Reactor Production of 99
A variety of intermediate- and low-level liquid and solid wastes are produced from reactor production of 99Mo using UAl alloy or UO2 targets and in principle can be collectively or individually converted into waste forms. At ANSTO, we have legacy acidic uranyl-nitrate-rich intermediate level waste (ILW) from the latter, and an alkaline liquid ILW, a U-rich filter cake, plus a shorter lived liquid stream that rapidly decays to low-level waste (LLW) standards, from the former. The options considered consist of cementitious products, glasses, glass-ceramics, or ceramics produced by vitrification or hot isostatic pressing for intermediate-level wastes. This paper discusses the progress in waste form development and processing to treat ANSTO’s ILW streams arising from 99Mo. The various waste forms and the reason for the process option chosen will be reviewed. We also address the concerns over adapting our chosen process for use in a hot-cell environment
Artificial Intelligence and Human Error Prevention: A Computer Aided Decision Making Approach: Final Report
Coordinated Science Laboratory was formerly known as Control Systems LaboratoryFederal Aviation Administration / FA79-WA-436
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