39 research outputs found
Working Group 11F Opening Comments NASA Planning for NASA's Future Ground Systems
These are simple charts for the introductory comments to be made at the start of a panel session at the Ground System Architecture Workshop (GSAW2016). It is not meant as a formal paper, but rather contains information to prompt further discussion of the panel members and audience. The panel topic is: Embracing Change via the Use of Service-Based Frameworks and Products in an Enterprise
Using Publish-Subscribe Messaging for System Status and Automation
The NASA Goddard Mission Services Evolution Center (GMSEC) system is a message-based plug-and-play open system architecture used in many of NASA mission operations centers. This presentation will focus on the use of GMSEC standard messages to report and analyze the status of a system and enable the automation of the system's components. In GMSEC systems, each component reports its status using a keep-alive message and also publishes status and activities as log messages. In addition, the components can accept functional directive messages from the GMSEC message bus. Over the past several years, development teams have found ways to utilize these messages to create innovative display pages and increasingly sophisticated approaches to automation. This presentation will show the flexibility and value of the message-based approach to system awareness and automation
Best Practices for Operations of Satellite Constellations
This paper presents the best practices used by several commercial and government operators of satellite constellations. These best practices were identified through a series of seminars and discussions held at NASA Goddard Space Flight Center (GSFC). The best practices are arrived through many years of experience and improvements made in the operations procedures and the operational systems with the primary drivers as mission safety and cost effectiveness. This paper discusses the operational aspects associated with how different organizations manage complexities of constellation operations. For the purposes of this paper, satellite constellations are groups of similar spacecraft with more than one spacecraft needed to fully accomplish the constellation's missio
A Successful Component Architecture for Interoperable and Evolvable Ground Data Systems
The National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) has adopted an open architecture approach for satellite control centers and is now realizing benefits beyond those originally envisioned. The Goddard Mission Services Evolution Center (GMSEC) architecture utilizes standardized interfaces and a middleware software bus to allow functional components to be easily integrated. This paper presents the GMSEC architectural goals and concepts, the capabilities enabled and the benefits realized by adopting this framework approach. NASA experiences with applying the GMSEC architecture on multiple missions are discussed. The paper concludes with a summary of lessons learned, future directions for GMSEC and the possible applications beyond NASA GSFC
Intriguing X-ray and optical variations of the gamma Cas analog HD45314
A growing number of Be and Oe stars, named the gamma Cas stars, are known for
their unusually hard and intense X-ray emission. This emission could either
trace accretion by a compact companion or magnetic interaction between the star
and its decretion disk. To test these scenarios, we carried out a detailed
optical monitoring of HD45314, the hottest member of the class of gamma Cas
stars, along with dedicated X-ray observations on specific dates.
High-resolution optical spectra were taken to monitor the emission lines formed
in the disk, while X-ray spectroscopy was obtained at epochs when the optical
spectrum of the Oe star was displaying peculiar properties. Over the last four
years, HD45314 has entered a phase of spectacular variations. The optical
emission lines have undergone important morphology and intensity changes
including transitions between single- and multiple-peaked emission lines as
well as shell events, and phases of (partial) disk dissipation. Photometric
variations are found to be anti-correlated with the equivalent width of the
H-alpha emission. Whilst the star preserved its hard and bright X-ray emission
during the shell phase, the X-ray spectrum during the phase of (partial) disk
dissipation was significantly softer and weaker. The observed behaviour of
HD45314 suggests a direct association between the level of X-ray emission and
the amount of material simultaneously present in the Oe disk as expected in the
magnetic star-disk interaction scenario.Comment: Accepted for publication in A&
Nationwide randomised trial evaluating elective neck dissection for early stage oral cancer (SEND study) with meta-analysis and concurrent real-world cohort
BACKGROUND: Guidelines remain unclear over whether patients with early stage oral cancer without overt neck disease benefit from upfront elective neck dissection (END), particularly those with the smallest tumours. // METHODS: We conducted a randomised trial of patients with stage T1/T2 N0 disease, who had their mouth tumour resected either with or without END. Data were also collected from a concurrent cohort of patients who had their preferred surgery. Endpoints included overall survival (OS) and disease-free survival (DFS). We conducted a meta-analysis of all six randomised trials. // RESULTS: Two hundred fifty randomised and 346 observational cohort patients were studied (27 hospitals). Occult neck disease was found in 19.1% (T1) and 34.7% (T2) patients respectively. Five-year intention-to-treat hazard ratios (HR) were: OS HR = 0.71 (p = 0.18), and DFS HR = 0.66 (p = 0.04). Corresponding per-protocol results were: OS HR = 0.59 (p = 0.054), and DFS HR = 0.56 (p = 0.007). END was effective for small tumours. END patients experienced more facial/neck nerve damage; QoL was largely unaffected. The observational cohort supported the randomised findings. The meta-analysis produced HR OS 0.64 and DFS 0.54 (p < 0.001). // CONCLUSION: SEND and the cumulative evidence show that within a generalisable setting oral cancer patients who have an upfront END have a lower risk of death/recurrence, even with small tumours. // CLINICAL TRIAL REGISTRATION: NIHR UK Clinical Research Network database ID number: UKCRN 2069 (registered on 17/02/2006), ISCRTN number: 65018995, ClinicalTrials.gov Identifier: NCT00571883
Subspecialty surveillance of long-term course of small and moderate muscular ventricular septal defect: heterogenous practices, low yield
Toward a Comprehensive Approach to the Collection and Analysis of Pica Substances, with Emphasis on Geophagic Materials
Pica, the craving and subsequent consumption of non-food substances such as earth, charcoal, and raw starch, has been an enigma for more than 2000 years. Currently, there are little available data for testing major hypotheses about pica because of methodological limitations and lack of attention to the problem.In this paper we critically review procedures and guidelines for interviews and sample collection that are appropriate for a wide variety of pica substances. In addition, we outline methodologies for the physical, mineralogical, and chemical characterization of these substances, with particular focus on geophagic soils and clays. Many of these methods are standard procedures in anthropological, soil, or nutritional sciences, but have rarely or never been applied to the study of pica.Physical properties of geophagic materials including color, particle size distribution, consistency and dispersion/flocculation (coagulation) should be assessed by appropriate methods. Quantitative mineralogical analyses by X-ray diffraction should be made on bulk material as well as on separated clay fractions, and the various clay minerals should be characterized by a variety of supplementary tests. Concentrations of minerals should be determined using X-ray fluorescence for non-food substances and inductively coupled plasma-atomic emission spectroscopy for food-like substances. pH, salt content, cation exchange capacity, organic carbon content and labile forms of iron oxide should also be determined. Finally, analyses relating to biological interactions are recommended, including determination of the bioavailability of nutrients and other bioactive components from pica substances, as well as their detoxification capacities and parasitological profiles.This is the first review of appropriate methodologies for the study of human pica. The comprehensive and multi-disciplinary approach to the collection and analysis of pica substances detailed here is a necessary preliminary step to understanding the nutritional enigma of non-food consumption