13 research outputs found
Benefits of Power and Propulsion Technology for a Piloted Electric Vehicle to an Asteroid
NASA's goal for human spaceflight is to expand permanent human presence beyond low Earth orbit (LEO). NASA is identifying potential missions and technologies needed to achieve this goal. Mission options include crewed destinations to LEO and the International Space Station; high Earth orbit and geosynchronous orbit; cis-lunar space, lunar orbit, and the surface of the Moon; near-Earth objects; and the moons of Mars, Mars orbit, and the surface of Mars. NASA generated a series of design reference missions to drive out required functions and capabilities for these destinations, focusing first on a piloted mission to a near-Earth asteroid. One conclusion from this exercise was that a solar electric propulsion stage could reduce mission cost by reducing the required number of heavy lift launches and could increase mission reliability by providing a robust architecture for the long-duration crewed mission. Similarly, solar electric vehicles were identified as critical for missions to Mars, including orbiting Mars, landing on its surface, and visiting its moons. This paper describes the parameterized assessment of power and propulsion technologies for a piloted solar electric vehicle to a near-Earth asteroid. The objective of the assessment was to determine technology drivers to advance the state of the art of electric propulsion systems for human exploration. Sensitivity analyses on the performance characteristics of the propulsion and power systems were done to determine potential system-level impacts of improved technology. Starting with a "reasonable vehicle configuration" bounded by an assumed launch date, we introduced technology improvements to determine the system-level benefits (if any) that those technologies might provide. The results of this assessment are discussed and recommendations for future work are described
A profusion of upstream open reading frame mechanisms in polyamine-responsive translational regulation
In many eukaryotic mRNAs one or more short ‘upstream’ open reading frames, uORFs, precede the initiator of the main coding sequence. Upstream ORFs are functionally diverse as illustrated by their variety of features in polyamine pathway biosynthetic mRNAs. Their propensity to act as sensors for regulatory circuits and to amplify the signals likely explains their occurrence in most polyamine pathway mRNAs. The uORF-mediated polyamine responsive autoregulatory circuits found in polyamine pathway mRNAs exemplify the translationally regulated dynamic interface between components of the proteome and metabolism
Adapting Agriculture to Climate Change: A Synopsis of Coordinated National Crop Wild Relative Seed Collecting Programs across Five Continents
The Adapting Agriculture to Climate Change Project set out to improve the diversity,
quantity, and accessibility of germplasm collections of crop wild relatives (CWR). Between 2013 and
2018, partners in 25 countries, heirs to the globetrotting legacy of Nikolai Vavilov, undertook seed
collecting expeditions targeting CWR of 28 crops of global significance for agriculture. Here, we
describe the implementation of the 25 national collecting programs and present the key results. A total
of 4587 unique seed samples from at least 355 CWR taxa were collected, conserved ex situ, safety
duplicated in national and international genebanks, and made available through the Multilateral
System (MLS) of the International Treaty on Plant Genetic Resources for Food and Agriculture (Plant
Treaty). Collections of CWR were made for all 28 targeted crops. Potato and eggplant were the most
collected genepools, although the greatest number of primary genepool collections were made for
rice. Overall, alfalfa, Bambara groundnut, grass pea and wheat were the genepools for which targets
were best achieved. Several of the newly collected samples have already been used in pre-breeding
programs to adapt crops to future challenges.info:eu-repo/semantics/publishedVersio
The draft genome of the hyperthermophilic archaeon Pyrodictium delaneyi strain hulk, an iron and nitrate reducer, reveals the capacity for sulfate reduction
Abstract Pyrodictium delaneyi strain Hulk is a newly sequenced strain isolated from chimney samples collected from the Hulk sulfide mound on the main Endeavour Segment of the Juan de Fuca Ridge (47.9501 latitude, −129.0970 longitude, depth 2200 m) in the Northeast Pacific Ocean. The draft genome of strain Hulk shared 99.77% similarity with the complete genome of the type strain Su06T, which shares with strain Hulk the ability to reduce iron and nitrate for respiration. The annotation of the genome of strain Hulk identified genes for the reduction of several sulfur-containing electron acceptors, an unsuspected respiratory capability in this species that was experimentally confirmed for strain Hulk. This makes P. delaneyi strain Hulk the first hyperthermophilic archaeon known to gain energy for growth by reduction of iron, nitrate, and sulfur-containing electron acceptors. Here we present the most notable features of the genome of P. delaneyi strain Hulk and identify genes encoding proteins critical to its respiratory versatility at high temperatures. The description presented here corresponds to a draft genome sequence containing 2,042,801 bp in 9 contigs, 2019 protein-coding genes, 53 RNA genes, and 1365 hypothetical genes
Health literacy, cognitive function, proper use, and adherence to inhaled asthma controller medications among older adults with asthma.
BACKGROUND: We sought to investigate the degree to which cognitive skills explain associations between health literacy and asthma-related medication use among older adults with asthma. METHODS: Patients aged ≥ 60 years receiving care at eight outpatient clinics (primary care, geriatrics, pulmonology, allergy, and immunology) in New York, New York, and Chicago, Illinois, were recruited to participate in structured, in-person interviews as part of the Asthma Beliefs and Literacy in the Elderly (ABLE) study (n = 425). Behaviors related to medication use were investigated, including adherence to prescribed regimens, metered-dose inhaler (MDI) technique, and dry powder inhaler (DPI) technique. Health literacy was measured using the Short Test of Functional Health Literacy in Adults. Cognitive function was assessed in terms of fluid (working memory, processing speed, executive function) and crystallized (verbal) ability. RESULTS: The mean age of participants was 68 years; 40% were Hispanic and 30% non-Hispanic black. More than one-third (38%) were adherent to their controller medication, 53% demonstrated proper DPI technique, and 38% demonstrated correct MDI technique. In multivariable analyses, limited literacy was associated with poorer adherence to controller medication (OR, 2.3; 95% CI, 1.29-4.08) and incorrect DPI (OR, 3.51; 95% CI, 1.81-6.83) and MDI (OR, 1.64; 95% CI, 1.01-2.65) techniques. Fluid and crystallized abilities were independently associated with medication behaviors. However, when fluid abilities were added to the model, literacy associations were reduced. CONCLUSIONS: Among older patients with asthma, interventions to promote proper medication use should simplify tasks and patient roles to overcome cognitive load and suboptimal performance in self-care