510 research outputs found

    Overview of lunar-based astronomy

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    The opportunities along with the advantages and disadvantages of the Moon for astronomical observatories are carefully and methodically considered. Taking a relatively unbiased approach, it was concluded that lunar observatories will clearly be a major factor in the future of astronomy in the next century. He concludes that ground based work will continue because of its accessibility and that Earth orbital work will remain useful, primarily for convenience of access in constructing and operating very large space systems. Deep space studies will feature not only probes but extensive systems for extremely long baseline studies at wavelengths from gamma rays through visible and IR out to radio is also a conclusion drawn, along with the consideration that lunar astronomy will have found important permanent applications along lines such as are discussed at the present symposium and others quite unsuspected today

    A very low frequency radio astronomy observatory on the Moon

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    Because of terrestrial ionospheric absorption, very little is known of the radio sky beyond 10 m wavelength. An extremely simple, low cost very low frequency radio telescope is proposed, consisting of a large array of short wires laid on the lunar surface, each wire equipped with an amplifier and a digitizer, and connected to a common computer. The telescope could do simultaneous multifrequency observations of much of the visible sky with high resolution in the 10 to 100 m wavelength range, and with lower resolution in the 100 to 1000 m range. It would explore structure and spectra of galactic and extragalactic point sources, objects, and clouds, and would produce detailed quasi-three-dimensional mapping of interstellar matter within several thousand parsecs of the Sun

    Planetary astronomy

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    Lunar-based astronomy offers major prospects for solar system research in the coming century. In addition to active advocacy of both ground-based and Lunar-based astronomy, a workshop on the value of asteroids as a resource for man is being organized. The following subject areas are also covered: (1) astrophysics from the Moon (composition and structure of planetary atmospheres); (2) a decade of cost-reduction in Very Large Telescopes (the SST as prototype of special-purpose telescopes); and (3) a plan for development of lunar astronomy

    Applications of active microwave imagery

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    The following topics were discussed in reference to active microwave applications: (1) Use of imaging radar to improve the data collection/analysis process; (2) Data collection tasks for radar that other systems will not perform; (3) Data reduction concepts; and (4) System and vehicle parameters: aircraft and spacecraft

    Radiation modeling in the Earth and Mars atmospheres using LRO/CRaTER with the EMMREM Module

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    Abstract We expand upon the efforts of Joyce et al. (2013), who computed the modulation potential at the Moon using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft along with data products from the Earth-Moon-Mars Radiation Environment Module (EMMREM). Using the computed modulation potential, we calculate galactic cosmic ray (GCR) dose and dose equivalent rates in the Earth and Mars atmospheres for various altitudes over the course of the LRO mission. While we cannot validate these predictions by directly comparable measurement, we find that our results conform to expectations and are in good agreement with the nearest available measurements and therefore may be used as reasonable estimates for use in efforts in risk assessment in the planning of future space missions as well as in the study of GCRs. PREDICCS (Predictions of radiation from REleASE, EMMREM, and Data Incorporating the CRaTER, COSTEP, and other solar energetic particles measurements) is an online system designed to provide the scientific community with a comprehensive resource on the radiation environments of the inner heliosphere. The data products shown here will be incorporated into PREDICCS in order to further this effort and daily updates will be made available on the PREDICCS website (http://prediccs.sr.unh.edu). Key Points We model GCR dose and dose equivalent rates in Earth and Mars atmospheres Dose rates are in reasonable agreement with nearby measurements Data products will soon be made available on PREDICCS website

    Outcomes in heart failure patients with preserved ejection fraction Mortality, readmission, and functional decline

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    AbstractObjectivesWe evaluated the six-month clinical trajectory of patients hospitalized for heart failure (HF) with preserved ejection fraction (EF), as the natural history of this condition has not been well established. We compared mortality, hospital readmission, and changes in functional status in patients with preserved versus depressed EF.BackgroundAlthough the poor prognosis of HF with depressed EF has been extensively documented, there are only limited and conflicting data concerning clinical outcomes for patients with preserved EF.MethodsWe prospectively evaluated 413 patients hospitalized for HF to determine whether EF ≥40% was an independent predictor of mortality, readmission, and the combined outcome of functional decline or death.ResultsAfter six months, 13% of patients with preserved EF died, compared with 21% of patients with depressed EF (p = 0.02). However, the rates of functional decline were similar among those with preserved and depressed EF (30% vs. 23%, respectively; p = 0.14). After adjusting for demographic and clinical covariates, preserved EF was associated with a lower risk of death (hazard ratio [HR] 0.49, 95% confidence interval [CI] 0.26 to 0.90; p = 0.02), but there was no difference in the risk of readmission (HR 1.01, 95% CI 0.72 to 1.43; p = 0.96) or the odds of functional decline or death (OR 1.01, 95% CI 0.59 to 1.72; p = 0.97).ConclusionsHeart failure with preserved EF confers a considerable burden on patients, with the risk of readmission, disability, and symptoms subsequent to hospital discharge, comparable to that of HF patients with depressed EF

    Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

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    Abstract The Sun and its solar wind are currently exhibiting extremely low densities and magnetic field strengths, representing states that have never been observed during the space age. The highly abnormal solar activity between cycles 23 and 24 has caused the longest solar minimum in over 80 years and continues into the unusually small solar maximum of cycle 24. As a result of the remarkably weak solar activity, we have also observed the highest fluxes of galactic cosmic rays in the space age and relatively small solar energetic particle events. We use observations from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter to examine the implications of these highly unusual solar conditions for human space exploration. We show that while these conditions are not a show stopper for long-duration missions (e.g., to the Moon, an asteroid, or Mars), galactic cosmic ray radiation remains a significant and worsening factor that limits mission durations. While solar energetic particle events in cycle 24 present some hazard, the accumulated doses for astronauts behind 10 g/cm2 shielding are well below current dose limits. Galactic cosmic radiation presents a more significant challenge: the time to 3% risk of exposure-induced death (REID) in interplanetary space was less than 400 days for a 30 year old male and less than 300 days for a 30 year old female in the last cycle 23–24 minimum. The time to 3% REID is estimated to be ∼20% lower in the coming cycle 24–25 minimum. If the heliospheric magnetic field continues to weaken over time, as is likely, then allowable mission durations will decrease correspondingly. Thus, we estimate exposures in extreme solar minimum conditions and the corresponding effects on allowable durations

    Formation of the oxygen torus in the inner magnetosphere: Van Allen Probes observations

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    We study the formation process of an oxygen torus during the 12–15 November 2012 magnetic storm, using the magnetic field and plasma wave data obtained by Van Allen Probes. We estimate the local plasma mass density (ρL) and the local electron number density (neL) from the resonant frequencies of standing Alfvén waves and the upper hybrid resonance band. The average ion mass (M) can be calculated by M ∼ ρL/neL under the assumption of quasi-neutrality of plasma. During the storm recovery phase, both Probe A and Probe B observe the oxygen torus at L = 3.0–4.0 and L = 3.7–4.5, respectively, on the morning side. The oxygen torus has M = 4.5–8 amu and extends around the plasmapause that is identified at L∼3.2–3.9. We find that during the initial phase, M is 4–7 amu throughout the plasma trough and remains at ∼1 amu in the plasmasphere, implying that ionospheric O+ ions are supplied into the inner magnetosphere already in the initial phase of the magnetic storm. Numerical calculation under a decrease of the convection electric field reveals that some of thermal O+ ions distributed throughout the plasma trough are trapped within the expanded plasmasphere, whereas some of them drift around the plasmapause on the dawnside. This creates the oxygen torus spreading near the plasmapause, which is consistent with the Van Allen Probes observations. We conclude that the oxygen torus identified in this study favors the formation scenario of supplying O+ in the inner magnetosphere during the initial phase and subsequent drift during the recovery phase

    An analytical method for total heavy metal complexing agents in water and its application to water quality studies

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    The principle research accomplishment on this project was the development of several methods of analysis for low levels of complexing agents, particularly chelating agents. These species are very important in water quality. It is only very recently that their importance has become very apparent in areas such as heavy metal transport, algal growth, and toxicity of heavy metals. The first method developed, was an atomic absorption analysis of strong heavy metal chelating agents. This method is based upon the fact that when copper ion is added to a water sample and the pH adjusted to 10, the only copper that remains in solution is that which is in a complexed or chelated form. The precipitate which comes out of the solution at pH 10 contains the copper which is not complexed or chelated and is removed by filtration. The copper remaining in solution is measured by atomic absorption. This copper concentration is a measure of the amount of chelating agent in the water and is called the copper equivalent chelating capacity of the water. The method was used on a number of natural water samples. It was found, for example, that normal creek water contains about one milligram per liter copper equivalent chelating capacity. Water supporting algal growth typically contains about the same level. Raw sewage from a nonindustrial source typically contains around 3 milligrams per liter copper equivalent chelating capacity, whereas properly treated sewage effluent contains 1 milligram per liter or less. The method was extended to the analysis of cyanide ion, a water pollutant found in mining and metal processing effluents. It is applicable to cyanide and provides a simple and convenient method for the analysis of this pollutant. In the final few weeks of the project, a new method was developed in which the copper is solublized from a copper-containing chelating ion exchange resin. This method is much more rapid than the first method described, though somewhat more subject to interferences. It is applicable to automated procedures and as a detection system for chelating agents separated by liquid chromatography. It is extremely sensitive and can detect as little as 5x10^-7 millimoles of NTA. These applications of the method are being pursued under a USDI-OWRR matching grant starting on July 1, 1973.Project # A-056-MO Agreement # 14-31-0001-382
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