463 research outputs found

    Launch Commit Criteria Monitoring Agent

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    The Spaceport Processing Systems Branch at NASA Kennedy Space Center has developed and deployed a software agent to monitor the Space Shuttle's ground processing telemetry stream. The application, the Launch Commit Criteria Monitoring Agent, increases situational awareness for system and hardware engineers during Shuttle launch countdown. The agent provides autonomous monitoring of the telemetry stream, automatically alerts system engineers when predefined criteria have been met, identifies limit warnings and violations of launch commit criteria, aids Shuttle engineers through troubleshooting procedures, and provides additional insight to verify appropriate troubleshooting of problems by contractors. The agent has successfully detected launch commit criteria warnings and violations on a simulated playback data stream. Efficiency and safety are improved through increased automation

    Community perceptions of a malaria vaccine in the Kintampo districts of Ghana.

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    BACKGROUND: Malaria remains the leading cause of morbidity and mortality in sub-Saharan Africa despite tools currently available for its control. Making malaria vaccine available for routine use will be a major hallmark, but its acceptance by community members and health professionals within the health system could pose considerable challenge as has been found with the introduction of polio vaccinations in parts of West Africa. Some of these challenges may not be expected since decisions people make are many a time driven by a complex myriad of perceptions. This paper reports knowledge and perceptions of community members in the Kintampo area of Ghana where malaria vaccine trials have been ongoing as part of the drive for the first-ever licensed malaria vaccine in the near future. METHODS: Both qualitative and quantitative methods were used in the data collection processes. Women and men whose children were or were not involved in the malaria vaccine trial were invited to participate in focus group discussions (FGDs). Respondents, made up of heads of religious groupings in the study area, health care providers, traditional healers and traditional birth attendants, were also invited to participate in in-depth interviews (IDIs). A cross-sectional survey was conducted in communities where the malaria vaccine trial (Mal 047RTS,S) was carried out. In total, 12 FGDs, 15 IDIs and 466 household head interviews were conducted. RESULTS: Knowledge about vaccines was widespread among participants. Respondents would like their children to be vaccinated against all childhood illnesses including malaria. Knowledge of the long existing routine vaccines was relatively high among respondents compared to hepatitis B and Haemophilus influenza type B vaccines that were introduced more recently in 2002. There was no clear religious belief or sociocultural practice that will serve as a possible barrier to the acceptance of a malaria vaccine. CONCLUSION: With the assumption that a malaria vaccine will be as efficacious as other EPI vaccines, community members in Central Ghana will accept and prefer malaria vaccine to malaria drugs as a malaria control tool. Beliefs and cultural practices as barriers to the acceptance of malaria vaccine were virtually unknown in the communities surveyed

    Correct Dosing of Artemether-Lumefantrine for Management of Uncomplicated Malaria in Rural Tanzania: Do facility and Patient Characteristics Matter?

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    Use of artemisinin-based combination therapy (ACT), such as artemether-lumefantrine (AL), requires a strict dosing schedule that follows the drugs' pharmacokinetic properties. The quality of malaria case management was assessed in two areas in rural Tanzania, to ascertain patient characteristics and facility-specific factors that influence correct dosing of AL for management of uncomplicated malaria. Exit interviews were conducted with patients attending health facilities for initial illness consultation. Information about health workers' training and supervision visits was collected. Health facilities were inventoried for capacity and availability of medical products related to care of malaria patients. The outcome was correct dosing of AL based on age and weight. Logistic regression was used to assess health facility factors and patient characteristics associated with correct dosing of AL by age and weight. A total of 1,531 patients were interviewed, but 60 pregnant women were excluded from the analysis. Only 503 (34.2%) patients who received AL were assessed for correct dosing. Most patients who received AL (85.3%) were seen in public health facilities, 75.7% in a dispensary and 91.1% in a facility that had AL in stock on the survey day. Overall, 92.1% (463) of AL prescriptions were correct by age or weight; but 85.7% of patients received correct dosing by weight alone and 78.5% received correct dosing by age alone. In multivariate analysis, patients in the middle dosing bands in terms of age or weight, had statistically significant lower odds of correct AL dosing (p < 0.05) compared to those in the lowest age or weight group. Other factors such as health worker supervision and training on ACT did not improve the odds of correct AL dosing. Although malaria treatment guidelines indicate AL dosing can be prescribed based on age or weight of the patient, findings from this study show that patients within the middle age and weight dosing bands were least likely to receive a correct dose by either measure. Clinicians should be made aware of AL dosing errors for patients aged three to 12 years and advised to use weight-based prescriptions whenever possible

    The role of cortical sensorimotor oscillations in action anticipation.

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    The human mirror neuron system is believed to play an important role in facilitating the ability of athletes to anticipate the actions of an opponent. This system is often assessed with EEG by measuring event-related changes in mu (8-13Hz) sensorimotor oscillations. However, traditional channel-based analyses of this measure are flawed in that due to volume conduction effects mu and non-mu alpha activity can become mixed. This flaw means it is unclear the extent to which mu activity indexes the mirror system, as opposed to other processes such as attentional demand. As a solution to this problem, we use independent component analysis to separate out the underlying brain processes during a tennis-related action observation and anticipation task. We investigated expertise-related differences in independent component activity. Experienced tennis players (N = 18) were significantly more accurate than unexperienced novices (N = 21) on the anticipation task. EEG results found significant group differences in both the mu and beta (15-25Hz) frequency bands in sensorimotor components, with earlier and greater desynchronization in the experienced tennis players. In particular, only experienced players showed desynchronization in the high mu (11-13Hz) band. No group differences were found in posterior alpha components. These results show for the first time that expertise differences during action observation and anticipation are unique to sensorimotor sources, and that no expertise-related differences exist in attention modulated, posterior alpha sources. As such, this paper provides a much cleaner measure of the human mirror system during action observation, and its modulation by motor expertise, than has been possible in previous work

    Induction of tumor-specific acquired immunity against already established tumors by selective stimulation of innate DEC-205+ dendritic cells

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    Two major distinct subsets of dendritic cells (DCs) are arranged to regulate our immune responses in vivo; 33D1+ and DEC-205+ DCs. Using anti-33D1-specific monoclonal antibody, 33D1+ DCs were successfully depleted from C57BL/6 mice. When 33D1+ DC-depleted mice were stimulated with LPS, serum IL-12, but not IL-10 secretion that may be mediated by the remaining DEC-205+ DCs was markedly enhanced, which may induce Th1 dominancy upon TLR signaling. The 33D1+ DC-depleted mice, implanted with syngeneic Hepa1-6 hepatoma or B16-F10 melanoma cells into the dermis, showed apparent inhibition of already established tumor growth in vivo when they were subcutaneously (sc) injected once or twice with LPS after tumor implantation. Moreover, the development of lung metastasis of B16-F10 melanoma cells injected intravenously was also suppressed when 33D1+ DC-deleted mice were stimulated twice with LPS in a similar manner, in which the actual cell number of NK1.1+CD3− NK cells in lung tissues was markedly increased. Furthermore, intraperitoneal (ip) administration of a very small amount of melphalan (l-phenylalanine mustard; l-PAM) (0.25 mg/kg) in LPS-stimulated 33D1+ DC-deleted mice helped to induce H-2Kb-restricted epitope-specific CD8+ cytotoxic T lymphocytes (CTLs) among tumor-infiltrating lymphocytes against already established syngeneic E.G7-OVA lymphoma. These findings indicate the importance and effectiveness of selective targeting of a specific subset of DCs, such as DEC-205+ DCs alone or with a very small amount of anticancer drugs to activate both CD8+ CTLs and NK effectors without externally added tumor antigen stimulation in vivo and provide a new direction for tumor immunotherapy

    Distinct Roles of Jasmonates and Aldehydes in Plant-Defense Responses

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    BACKGROUND: Many inducible plant-defense responses are activated by jasmonates (JAs), C(6)-aldehydes, and their corresponding derivatives, produced by the two main competing branches of the oxylipin pathway, the allene oxide synthase (AOS) and hydroperoxide lyase (HPL) branches, respectively. In addition to competition for substrates, these branch-pathway-derived metabolites have substantial overlap in regulation of gene expression. Past experiments to define the role of C(6)-aldehydes in plant defense responses were biased towards the exogenous application of the synthetic metabolites or the use of genetic manipulation of HPL expression levels in plant genotypes with intact ability to produce the competing AOS-derived metabolites. To uncouple the roles of the C(6)-aldehydes and jasmonates in mediating direct and indirect plant-defense responses, we generated Arabidopsis genotypes lacking either one or both of these metabolites. These genotypes were subsequently challenged with a phloem-feeding insect (aphids: Myzus persicae), an insect herbivore (leafminers: Liriomyza trifolii), and two different necrotrophic fungal pathogens (Botrytis cinerea and Alternaria brassicicola). We also characterized the volatiles emitted by these plants upon aphid infestation or mechanical wounding and identified hexenyl acetate as the predominant compound in these volatile blends. Subsequently, we examined the signaling role of this compound in attracting the parasitoid wasp (Aphidius colemani), a natural enemy of aphids. PRINCIPAL FINDINGS: This study conclusively establishes that jasmonates and C(6)-aldehydes play distinct roles in plant defense responses. The jasmonates are indispensable metabolites in mediating the activation of direct plant-defense responses, whereas the C(6)-aldehyes are not. On the other hand, hexenyl acetate, an acetylated C(6)-aldehyde, is the predominant wound-inducible volatile signal that mediates indirect defense responses by directing tritrophic (plant-herbivore-natural enemy) interactions. SIGNIFICANCE: The data suggest that jasmonates and hexenyl acetate play distinct roles in mediating direct and indirect plant-defense responses. The potential advantage of this "division of labor" is to ensure the most effective defense strategy that minimizes incurred damages at a reduced metabolic cost

    The effects of spatial legacies following shifting management practices and fire on boreal forest age structure

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    Forest age structure and its spatial arrangement are important elements of sustainable forestry because of their effects on biodiversity and timber availability. Forest management objectives that include specific forest age structure may not be easily attained due to constraints imposed by the legacies of historical management and natural disturbance. We used a spatially explicit stochastic model to explore the synergetic effects of forest management and fire on boreal forest age structure. Specifically, we examined (1) the duration of spatial legacies of different management practices in the boreal forest, (2) how multiple shifts in management practices affect legacy duration and the spatial trajectories of forest age structure, and (3) how fire influences legacy duration and pattern development in combination with harvesting. Results based on 30 replicates of 500 years for each scenario indicate that (1) spatial legacies persist over 200 years and the rate at which legacies are overcome depends on whether new management targets are in synchrony with existing spatial pattern; (2) age specific goals were met faster after multiple management shifts due to the similar spatial scale of the preceding management types; (3) because large fires can erase the spatial pattern created by smaller disturbances, scenarios with fire had shorter lags than scenarios without fire. These results suggest that forest management goals can be accelerated by applying management at a similar spatial scale as existing spatial patterns. Also, management planning should include careful consideration of historical management as well as current and likely future disturbances

    Comparative Pathogenesis of Three Human and Zoonotic SARS-CoV Strains in Cynomolgus Macaques

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    The severe acute respiratory syndrome (SARS) epidemic was characterized by increased pathogenicity in the elderly due to an early exacerbated innate host response. SARS-CoV is a zoonotic pathogen that entered the human population through an intermediate host like the palm civet. To prevent future introductions of zoonotic SARS-CoV strains and subsequent transmission into the human population, heterologous disease models are needed to test the efficacy of vaccines and therapeutics against both late human and zoonotic isolates. Here we show that both human and zoonotic SARS-CoV strains can infect cynomolgus macaques and resulted in radiological as well as histopathological changes similar to those seen in mild human cases. Viral replication was higher in animals infected with a late human phase isolate compared to a zoonotic isolate. While there were significant differences in the number of host genes differentially regulated during the host responses between the three SARS-CoV strains, the top pathways and functions were similar and only apparent early during infection with the majority of genes associated with interferon signaling pathways. This study characterizes critical disease models in the evaluation and licensure of therapeutic strategies against SARS-CoV for human use

    Poorer White Matter Microstructure Predicts Slower and More Variable Reaction Time Performance: Evidence for a Neural Noise Hypothesis in a Large Lifespan Cohort

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    Most prior research has focused on characterizing averages in cognition, brain characteristics, or behavior, and attempting to predict differences in these averages among individuals. However, this overwhelming focus on mean levels may leave us with an incomplete picture of what drives individual differences in behavioral phenotypes by ignoring the variability of behavior around an individual's mean. In particular, enhanced white matter (WM) structural microstructure has been hypothesized to support consistent behavioral performance by decreasing Gaussian noise in signal transfer. Conversely, lower indices of WM microstructure are associated with greater within-subject variance in the ability to deploy performance-related resources, especially in clinical populations. We tested a mechanistic account of the “neural noise” hypothesis in a large adult lifespan cohort (Cambridge Centre for Ageing and Neuroscience) with over 2500 adults (ages 18-102; 1508 female; 1173 male; 2681 behavioral sessions; 708 MRI scans) using WM fractional anisotropy to predict mean levels and variability in reaction time performance on a simple behavioral task using a dynamic structural equation model. By modeling robust and reliable individual differences in within-person variability, we found support for a neural noise hypothesis (Kail, 1997), with lower fractional anisotropy predicted individual differences in separable components of behavioral performance estimated using dynamic structural equation model, including slower mean responses and increased variability. These effects remained when including age, suggesting consistent effects of WM microstructure across the adult lifespan unique from concurrent effects of aging. Crucially, we show that variability can be reliably separated from mean performance using advanced modeling tools, enabling tests of distinct hypotheses for each component of performance

    Ageing increases reliance on sensorimotor prediction through structural and functional differences in frontostriatal circuits

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    This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Nature Publishing Group.The control of voluntary movement changes markedly with age. A critical component of motor control is the integration of sensory information with predictions of the consequences of action, arising from internal models of movement. This leads to sensorimotor attenuation – a reduction in the perceived intensity of sensations from self-generated compared to external actions. Here we show that sensorimotor attenuation occurs in 98% of adults in a population-based cohort (n=325; 18-88 years; the Cambridge Centre for Ageing and Neuroscience). Importantly, attenuation increases with age, in proportion to reduced sensory sensitivity. This effect is associated with differences in the structure and functional connectivity of the pre-supplementary motor area (pre-SMA), assessed with magnetic resonance imaging. The results suggest that ageing alters the balance between the sensorium and predictive models, mediated by the pre-SMA and its connectivity in frontostriatal circuits. This shift may contribute to the motor and cognitive changes observed with age.Cam-CAN research was supported by the Biotechnology and Biological Sciences Research Council (BB/H008217/1). JBR and NW were supported by the James S. McDonnell Foundation 21st Century Science Initiative, Scholar Award in Understanding Human Cognition. JBR was also supported by Wellcome Trust [103838] and the Medical Research Council [MC-A060-5PQ30]. DMW was supported by the Wellcome Trust [097803], Human Frontier Science Program and the Royal Society Noreen Murray Professorship in Neurobiology. RNH was supported by the Medical Research Council [MC-A060-5PR10]. RAK was supported by a Sir Henry Wellcome Trust Postdoctoral Fellowship [107392]. LG was funded by a Rubicon grant from the Netherlands Organisation for Scientific Research (NWO)
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