548 research outputs found
Study of onboard expert systems to augment space shuttle and space station autonomy
The feasibility of onboard crew activity planning was examined. The use of expert systems technology to aid crewmembers in locating stowed equipment was also investigated. The crew activity planning problem, along with a summary of past and current research efforts, was discussed in detail. The requirements and specifications used to develop the crew activity planning system was also defined. The guidelines used to create, develop, and operate the MFIVE Crew Scheduler and Logistics Clerk were discussed. Also discussed is the mathematical algorithm, used by the MFIVE Scheduler, which was developed to aid in optimal crew activity planning
Space Applications of Automation, Robotics and Machine Intelligence Systems (ARAMIS), phase 2. Volume 1: Telepresence technology base development
The field of telepresence is defined, and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA's plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies over the next decade are included. Several space projects are examined in detail to determine what capabilities are required of a telepresence system in order to accomplish various tasks, such as servicing and assembly. The key operational and technological areas are identified, conclusions and recommendations are made for further research, and an example developmental program is presented, leading to an operational telepresence servicer
Space applications of Automation, Robotics And Machine Intelligence Systems (ARAMIS). Volume 3, phase 2: Executive summary
The field of telepresence is defined, and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA's plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies are included. Several space projects are examined in detail to determine what capabilities are required of a telepresence system in order to accomplish various tasks, such as servicing and assembly. The key operational and technological areas are identified, conclusions and recommendations are made for further research, and an example developmental program leading to an operational telepresence servicer is presented
Space Applications of Automation, Robotics and Machine Intelligence Systems (ARAMIS), phase 2. Volume 2: Telepresence project applications
The field of telepresence is defined and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA' plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies over the next decade are included
Monitoring and modeling infiltration–recharge dynamics of managed aquifer recharge with desalinated seawater
We study the relation between surface infiltration and groundwater
recharge during managed aquifer recharge (MAR) with desalinated seawater in
an infiltration pond, at the Menashe site that overlies the northern part of
the Israeli Coastal Aquifer. We monitor infiltration dynamics at multiple
scales (up to the scale of the entire pond) by measuring the ponding depth,
sediment water content and groundwater levels, using pressure sensors,
single-ring infiltrometers, soil sensors, and observation wells. During a
month (January 2015) of continuous intensive MAR
(2.45  ×  10<sup>6</sup> m<sup>3</sup> discharged to a 10.7 ha area),
groundwater level has risen by 17 m attaining full connection with the pond,
while average infiltration rates declined by almost 2 orders of magnitude
(from  ∼  11 to  ∼  0.4 m d<sup>−1</sup>). This reduction can be
explained solely by the lithology of the unsaturated zone that includes
relatively low-permeability sediments. Clogging processes at the pond-surface
– abundant in many MAR operations – are negated by the high-quality
desalinated seawater (turbidity  ∼  0.2 NTU, total dissolved solids
 ∼  120 mg L<sup>−1</sup>) or negligible compared to the low-permeability
layers. Recharge during infiltration was estimated reasonably well by simple
analytical models, whereas a numerical model was used for estimating
groundwater recharge after the end of infiltration. It was found that a
calibrated numerical model with a one-dimensional representative sediment
profile is able to capture MAR dynamics, including temporal reduction of
infiltration rates, drainage and groundwater recharge. Measured infiltration
rates of an independent MAR event (January 2016) fitted well to those
calculated by the calibrated numerical model, showing the model validity. The
successful quantification methodologies of the temporal groundwater recharge
are useful for MAR practitioners and can serve as an input for groundwater
flow models
Polycystic kidney disease: an unrecognized emerging infectious disease?
Polycystic kidney disease (PKD) is one of the most common genetic diseases in humans. We contend that it may be an emerging infectious disease and/or microbial toxicosis in a vulnerable human subpopulation. Use of a differential activation protocol for the Limulus amebocyte lysate (LAL) assay showed bacterial endotoxin and fungal (1-->3)-beta-D-glucans in cyst fluids from human kidneys with PKD. Fatty acid analysis of cyst fluid confirmed the presence of 3-hydroxy fatty acids characteristic of endotoxin. Tissue and cyst fluid from three PKD patients were examined for fungal components. Serologic tests showed Fusarium, Aspergillus, and Candida antigens. IgE, but not IgG, reactive with Fusarium and Candida were also detected in cyst fluid. Fungal DNA was detected in kidney tissue and cyst fluid from these three PKD patients, but not in healthy human kidney tissue. We examine the intertwined nature of the actions of endotoxin and fungal components, sphingolipid biology in PKD, the structure of PKD gene products, infections, and integrity of gut function to establish a mechanistic hypothesis for microbial provocation of human cystic disease. Proof of this hypothesis will require identification of the microbes and microbial components involved and multifaceted studies of PKD cell biology
Clinical validation of a targeted methylation-based multi-cancer early detection test using an independent validation set
BACKGROUND: A multi-cancer early detection (MCED) test used to complement existing screening could increase the number of cancers detected through population screening, potentially improving clinical outcomes. The Circulating Cell-free Genome Atlas study (CCGA; NCT02889978) was a prospective, case-controlled, observational study and demonstrated that a blood-based MCED test utilizing cell-free DNA (cfDNA) sequencing in combination with machine learning could detect cancer signals across multiple cancer types and predict cancer signal origin (CSO) with high accuracy. The objective of this third and final CCGA substudy was to validate an MCED test version further refined for use as a screening tool. PATIENTS AND METHODS: This pre-specified substudy included 4077 participants in an independent validation set (cancer: n = 2823; non-cancer: n = 1254, non-cancer status confirmed at year-one follow-up). Specificity, sensitivity, and CSO prediction accuracy were measured. RESULTS: Specificity for cancer signal detection was 99.5% [95% confidence interval (CI): 99.0% to 99.8%]. Overall sensitivity for cancer signal detection was 51.5% (49.6% to 53.3%); sensitivity increased with stage [stage I: 16.8% (14.5% to 19.5%), stage II: 40.4% (36.8% to 44.1%), stage III: 77.0% (73.4% to 80.3%), stage IV: 90.1% (87.5% to 92.2%)]. Stage I-III sensitivity was 67.6% (64.4% to 70.6%) in 12 pre-specified cancers that account for approximately two-thirds of annual USA cancer deaths and was 40.7% (38.7% to 42.9%) in all cancers. Cancer signals were detected across >50 cancer types. Overall accuracy of CSO prediction in true positives was 88.7% (87.0% to 90.2%). CONCLUSION: In this pre-specified, large-scale, clinical validation substudy, the MCED test demonstrated high specificity and accuracy of CSO prediction and detected cancer signals across a wide diversity of cancers. These results support the feasibility of this blood-based MCED test as a complement to existing single-cancer screening tests. CLINICAL TRIAL NUMBER: NCT02889978
Managed aquifer recharge with reverse-osmosis desalinated seawater: modeling the spreading in groundwater using stable water isotopes
The spreading of reverse-osmosis desalinated seawater (DSW) in the Israeli
coastal aquifer was studied using groundwater modeling and stable water
isotopes as tracers. The DSW produced at the Hadera seawater reverse-osmosis
(SWRO) desalination plant is recharged into the aquifer through an infiltration pond at the managed
aquifer recharge (MAR) site of Menashe, Israel. The distinct difference in isotope composition between DSW
(δ18O  =  1.41 ‰;
δ2H  =  11.34 ‰) and the natural groundwater
(δ18O  =  −4.48 ‰ to −5.43 ‰;
δ2H  =  −18.41 ‰ to −22.68 ‰) makes
the water isotopes preferable for use as a tracer compared to widely used
chemical tracers, such as chloride. Moreover, this distinct difference can be
used to simplify the system to a binary mixture of two end-members:
desalinated seawater and groundwater. This approach is validated through a
sensitivity analysis, and it is especially robust when spatial data of stable
water isotopes in the aquifer are scarce. A calibrated groundwater flow and
transport model was used to predict the DSW plume distribution in the aquifer
after 50Â years of MAR with DSW. The results suggest that after 50Â years,
94 % of the recharged DSW was recovered by the production wells at the
Menashe MAR site. The presented methodology is useful for predicting the
distribution of reverse-osmosis desalinated seawater in various downstream
groundwater systems.</p
A Systematic Review and Meta-Analysis to Inform Cancer Screening Guidelines in Idiopathic Inflammatory Myopathies
OBJECTIVES: To identify clinical factors associated with cancer risk in the idiopathic inflammatory myopathies (IIMs) and to systematically review the existing evidence related to cancer screening. METHODS: A systematic literature search was carried out on Medline, Embase and Scopus. Cancer risk within the IIM population (i.e. not compared to the general population) was expressed as risk ratios (RR) for binary variables and weighted mean differences (WMD) for continuous variables. Evidence relating to cancer screening practices in the IIMs were synthesised via narrative review. RESULTS: Sixty nine studies were included in the meta-analysis. Dermatomyositis subtype (RR 2.21), older age (WMD 11.19), male gender (RR 1.53), dysphagia (RR 2.09), cutaneous ulceration (RR 2.73), and anti-transcriptional intermediary factor-1 gamma positivity (RR 4.66) were identified as being associated with significantly increased risk of cancer. Polymyositis (RR 0.49) and clinically amyopathic dermatomyositis (RR 0.44) subtypes, Raynaud's phenomenon (RR 0.61), interstitial lung disease (RR 0.49), very high serum creatine kinase (WMD -1189.96) or lactate dehydrogenase (WMD -336.52) levels, and anti-Jo1 (RR 0.45) or anti-EJ (RR 0.17) positivity were identified as being associated with significantly reduced risk of cancer. Nine studies relating to IIM-specific cancer screening were included. Computed tomography (CT) scanning of the thorax, abdomen and pelvis appeared to be effective in identifying underlying asymptomatic cancers. DISCUSSION: Cancer risk factors should be evaluated in patients with IIM for risk stratification. Screening evidence is limited but CT scanning could be useful. Prospective studies and consensus guidelines are needed to establish cancer screening strategies in IIM patients
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