549 research outputs found
Analysis of navigation performance for the Earth Observing System (EOS) using the TDRSS Onboard Navigation System (TONS)
Use of the Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) was proposed as an alternative to the Global Positioning System (GPS) for supporting the Earth Observing System (EOS) mission. The results are presented of EOS navigation performance evaluation with respect to TONS based orbit, time, and frequency determination (OD/TD/FD). Two TONS modes are considered: one uses scheduled TDRSS forward link service to derive one way Doppler tracking data for OD/FD support (TONS-I); the other uses an unscheduled navigation beacon service (proposed for Advanced TDRSS) to obtain pseudorange and Doppler data for OD/TD/FD support (TONS-II). Key objectives of the analysis were to evaluate nominal performance and potential sensitivities, such as suboptimal tracking geometry, tracking contact scheduling, and modeling parameter selection. OD/TD/FD performance predictions are presented based on covariance and simulation analyses. EOS navigation scenarios and the contributions of principal error sources impacting performance are also described. The results indicate that a TONS mode can be configured to meet current and proposed EOS position accuracy requirements of 100 and 50 m, respectively
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Human gut Bacteroides capture vitamin B12 via cell surface-exposed lipoproteins.
Human gut Bacteroides use surface-exposed lipoproteins to bind and metabolize complex polysaccharides. Although vitamins and other nutrients are also essential for commensal fitness, much less is known about how commensal bacteria compete with each other or the host for these critical resources. Unlike in Escherichia coli, transport loci for vitamin B12 (cobalamin) and other corrinoids in human gut Bacteroides are replete with conserved genes encoding proteins whose functions are unknown. Here we report that one of these proteins, BtuG, is a surface-exposed lipoprotein that is essential for efficient B12 transport in B. thetaiotaomicron. BtuG binds B12 with femtomolar affinity and can remove B12 from intrinsic factor, a critical B12 transport protein in humans. Our studies suggest that Bacteroides use surface-exposed lipoproteins not only for capturing polysaccharides, but also to acquire key vitamins in the gut
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Characterization of Pathogenicity, Virulence and Host-Pathogen Interractions
The threats of bio-terrorism and newly emerging infectious diseases pose serious challenges to the national security infrastructure. Rapid detection and diagnosis of infectious disease in human populations, as well as characterizing pathogen biology, are critical for reducing the morbidity and mortality associated with such threats. One of the key challenges in managing an infectious disease outbreak, whether through natural causes or acts of overt terrorism, is detection early enough to initiate effective countermeasures. Much recent attention has been directed towards the utility of biomarkers or molecular signatures that result from the interaction of the pathogen with the host for improving our ability to diagnose and mitigate the impact of a developing infection during the time window when effective countermeasures can be instituted. Host responses may provide early signals in blood even from localized infections. Multiple innate and adaptive immune molecules, in combination with other biochemical markers, may provide disease-specific information and new targets for countermeasures. The presence of pathogen specific markers and an understanding of the molecular capabilities and adaptations of the pathogen when it interacts with its host may likewise assist in early detection and provide opportunities for targeting countermeasures. An important question that needs to be addressed is whether these molecular-based approaches will prove useful for early diagnosis, complement current methods of direct agent detection, and aid development and use of countermeasures. Lawrence Livermore National Laboratory (LLNL) will host a workshop to explore the utility of host- and pathogen-based molecular diagnostics, prioritize key research issues, and determine the critical steps needed to transition host-pathogen research to tools that can be applied towards a more effective national bio-defense strategy. The workshop will bring together leading researchers/scientists in the area of host-pathogen interactions as well as policy makers from federal agencies. The main objectives of the workshop are: (1) to assess the current national needs, capabilities, near-term technologies, and future challenges in applying various diagnostics tools to public health and bio-defense; (2) to evaluate the utility and feasibility of host-response and pathogen biomarker profiling in the diagnosis and management of infectious diseases; and (3) to create a comprehensive developmental strategy from proof-of-concept, through validation, to deployment of appropriate advanced technology for the clinical/public health and bio-defense environments
MODIS information, data and control system (MIDACS) operations concepts
The MODIS Information, Data, and Control System (MIDACS) Operations Concepts Document provides a basis for the mutual understanding between the users and the designers of the MIDACS, including the requirements, operating environment, external interfaces, and development plan. In defining the concepts and scope of the system, how the MIDACS will operate as an element of the Earth Observing System (EOS) within the EosDIS environment is described. This version follows an earlier release of a preliminary draft version. The individual operations concepts for planning and scheduling, control and monitoring, data acquisition and processing, calibration and validation, data archive and distribution, and user access do not yet fully represent the requirements of the data system needed to achieve the scientific objectives of the MODIS instruments and science teams. The teams are not yet formed; however, it is possible to develop the operations concepts based on the present concept of EosDIS, the level 1 and level 2 Functional Requirements Documents, and through interviews and meetings with key members of the scientific community. The operations concepts were exercised through the application of representative scenarios
MODIS information, data and control system (MIDACS) level 2 functional requirements
The MODIS Information, Data and Control System (MIDACS) Level 2 Functional Requirements Document establishes the functional requirements for MIDACS and provides a basis for the mutual understanding between the users and the designers of the EosDIS, including the requirements, operating environment, external interfaces, and development plan. In defining the requirements and scope of the system, this document describes how MIDACS will operate as an element of the EOS within the EosDIS environment. This version of the Level 2 Requirements Document follows an earlier release of a preliminary draft version. The sections on functional and performance requirements do not yet fully represent the requirements of the data system needed to achieve the scientific objectives of the MODIS instruments and science teams. Indeed, the team members have not yet been selected and the team has not yet been formed; however, it has been possible to identify many relevant requirements based on the present concept of EosDIS and through interviews and meetings with key members of the scientific community. These requirements have been grouped by functional component of the data system, and by function within each component. These requirements have been merged with the complete set of Level 1 and Level 2 context diagrams, data flow diagrams, and data dictionary
MODIS Information, Data, and Control System (MIDACS) system specifications and conceptual design
The MODIS Information, Data, and Control System (MIDACS) Specifications and Conceptual Design Document discusses system level requirements, the overall operating environment in which requirements must be met, and a breakdown of MIDACS into component subsystems, which include the Instrument Support Terminal, the Instrument Control Center, the Team Member Computing Facility, the Central Data Handling Facility, and the Data Archive and Distribution System. The specifications include sizing estimates for the processing and storage capacities of each data system element, as well as traffic analyses of data flows between the elements internally, and also externally across the data system interfaces. The specifications for the data system, as well as for the individual planning and scheduling, control and monitoring, data acquisition and processing, calibration and validation, and data archive and distribution components, do not yet fully specify the data system in the complete manner needed to achieve the scientific objectives of the MODIS instruments and science teams. The teams have not yet been formed; however, it was possible to develop the specifications and conceptual design based on the present concept of EosDIS, the Level-1 and Level-2 Functional Requirements Documents, the Operations Concept, and through interviews and meetings with key members of the scientific community
A qualitative study of factors related to cardiometabolic risk in rural men
Abstract Background Rural men are known to have poor health behaviors, which contribute to their elevated burden of cardiometabolic disorders in the United States. Although regular physical activity, healthy eating, and avoiding tobacco can reduce cardiometabolic risk, little is known about how to engage rural men in health promotion programs. To bridge this gap in evidence, we investigate knowledge of modifiable cardiometabolic risk factors among rural men in the western United States, identify their concerns related to heart health and motivation to reduce risk, and explore individual, social, and community-level influences on heart-healthy behaviors, specifically diet, physical activity, and tobacco use. Methods We conducted seven focus groups with 54 sedentary, overweight/obese men (mean body mass index [BMI] = 31.3 ± 4.6) aged 43–88 residing in government-designated “medically underserved” rural Montana towns in September and October 2014. All sessions were audio-recorded and transcribed verbatim. Transcripts were coded and analyzed thematically using Nvivo software. Participants also completed a brief questionnaire about personal characteristics and health behaviors. These data were explored descriptively. Results Despite being classified as overweight/obese and sedentary, no participants reported to be in poor health. Many men described health relative to self-reliance and the ability to participate in outdoor recreation; concern with health appeared to be related to age. Participants were generally knowledgeable of heart-healthy behaviors, but many felt fatalistic about their own risk. Catalysts for behavior change included a serious medical event in the household and desire to reduce aging-associated functional decline. Barriers to adopting and maintaining healthy eating and physical activity habits and abstaining from tobacco included normative beliefs around masculinity and individual liberty, the limited social universe of small towns, winter weather, time constraints, and preferences for unhealthy foods. Facilitators included behavioral self-monitoring, exercising with a partner, and opportunities for preferred activities, such as hunting and team sports. Conclusions These findings provide important insight about influences on rural men’s health behaviors and provide guidance for possible intervention strategies to promote cardiometabolic health. Trial registration ClinicalTrials.gov NCT02499731 . Registered 1 July 2015
A High-Density Linkage Map of the Ancestral Diploid Strawberry, Fragaria iinumae, Constructed with Single Nucleotide Polymorphism Markers from the IStraw90 Array and Genotyping by Sequencing
Fragaria iinumae Makino is recognized as an ancestor of the octoploid strawberry species, which includes the cultivated strawberry, Fragaria ×ananassa Duchesne ex Rozier. Here we report the construction of the first high-density linkage map for F. iinumae. The F. iinumae linkage map (Fii map) is based on two high-throughput techniques of single nucleotide polymorphism (SNP) genotyping: the IStraw90 Array (hereafter “Array”), and genotyping by sequencing (GBS). The F2 generation mapping population was derived by selfing F. iinumae hybrid F1D, the product of a cross between two divergent F. iinumae accessions collected from Hokkaido, Japan. The Fii map consists of seven linkage groups (LGs) and has an overall length of 451.7 cM as defined by 496 loci populated by 4173 markers: 3280 from the Array and 893 from GBS. Comparisons with two versions of the Fragaria vesca ssp. vesca L. ‘Hawaii 4’ pseudo-chromosome (PC) assemblies reveal substantial conservation of synteny and colinearity, yet identified differences that point to possible genomic divergences between F. iinumae and F. vesca, and/or to F. vesca genomic assembly errors. The Fii map provides a basis for anchoring a F. iinumae genome assembly as a prerequisite for constructing a second diploid reference genome for Fragaria
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Transition-ready technologies and expertise from the Chemical and Biological National Security Program at LLNL
HSARPA has initiated a new Bioinformatics and Assay Development solicitation, BIAD2 (BAA 06-01), to address a number of technology gaps and requirements for biodetection (www.hsarpabaa.com). This solicitation will leverage the vast research and development capabilities of the private sector and academia in order to meet the needs of HSARPA and Homeland Security. In order to meet these requirements, this solicitation will: (1) Develop and validate actionable assays for the public and private sector; (2) Develop and validate new assays and novel assay methodologies to enhance existing detection systems and enable future detection platforms; (3) Develop next generation assays which are robust against novel, emerging and engineered threats; (4) Develop novel assays that detect low levels of ribonucleic acid (RNA)-based viral threats in complex backgrounds; (5) Develop novel assays to characterize the viability, degree of virulence or toxicity, and countermeasure resistance of a biological agent; and (6) Develop new bioinformatics tools to support assay development and assay validation The Lawrence Livermore National Laboratory (LLNL) Bioassays and Signature Program (BSP) develops nationally-validated detection and identification assays to cover the full range of biological threat agents, starting from human, animal, and plant pathogens on the Select Agent list. The assays that have been co-developed by the CDC and the BSP are used internationally and represent the gold standard for molecular detection of select agent pathogens for the public health community. They are also used in the DHS environmental monitoring operations such as BioWatch and DHS National Security Special Events support. These reagents have been used to process and analyze more than 5 million samples and have delivered exceptional performance for the end users, with zero false positives since their deployment. Currently, highly-multiplexed nucleic acid assays that represent the ''next-generation'' in BioWatch assays have been developed at LLNL and are in final evaluation at CDC. LLNL is a full partner to the LRN network, as well as a formal LRN member, sanctioned to perform these diagnostics on field samples. The Program has assay extensive experience developing, testing, validating, deploying, and commercializing biodetection assays and instrumentation. The following pages contain additional descriptions of our Program's capabilities. We have a demonstrated track record of established collaborations and look forward to partnering with offerers to the HSARPA BAA to continue to meet the national needs and requirements
Preliminary Design Considerations for Access and Operations in Earth-Moon L1/L2 Orbits
Within the context of manned spaceflight activities, Earth-Moon libration point orbits could support lunar surface operations and serve as staging areas for future missions to near-Earth asteroids and Mars. This investigation examines preliminary design considerations including Earth-Moon L1/L2 libration point orbit selection, transfers, and stationkeeping costs associated with maintaining a spacecraft in the vicinity of L1 or L2 for a specified duration. Existing tools in multi-body trajectory design, dynamical systems theory, and orbit maintenance are leveraged in this analysis to explore end-to-end concepts for manned missions to Earth-Moon libration points
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