159 research outputs found
Future Missions to the Giant Planets that Can Advance Atmospheric Science Objectives:Space Science Reviews
Other papers in this special issue have discussed the diversity of planetary atmospheres and some of the key science questions for giant planet atmospheres to be addressed in the future. There are crucial measurements that can only be made by orbiters of giant planets and probes dropped into their atmospheres. To help the community be more effective developers of missions and users of data products, we summarize how NASA and ESA categorize their planetary space missions, and the restrictions and requirements placed on each category. We then discuss the atmospheric goals to be addressed by currently approved giant-planet missions as well as missions likely to be considered in the next few years, such as a joint NASA/ESA Ice Giant orbiter with atmospheric probe. Our focus is on interplanetary spacecraft, but we acknowledge the crucial role to be played by ground-based and near-Earth telescopes, as well as theoretical and laboratory work. © 2020, Springer Nature B.V
Prediction of Severe Complications and Mortality in Patients Admitted to a Coronary Care Unit
The aim of this study was to design a statistical model which will predict death or life-threatening complications in patients admitted to Coronary Care Unit using data which is available at the time of presentation. The study included 3721 consecutive admissions over a period four year period. Predictive models were developed using logistic regression analysis (with data from 1000 patients) and their performance was assessed using receiver operating characteristic (ROC) curve analysis. The most useful model included nine data items and was tested on data from 2721 patients. These could be divided into four groups according to their calculated probability of developing a serious complication. The lowest risk group had a mortality of 0.05%, compared with 3.5%, 6.4% and 18.1% respectively in the higher risk groups (p1000 U/1) in the four groups was 14.1%, 21.2%, 46.9% and 51.5% respectively (p<0.001). The overall complication rates were 16.9%, 35.4%, 75.4% and 71.8% respectively (p<0.001)
Large negative velocity gradients in Burgers turbulence
We consider 1D Burgers equation driven by large-scale white-in-time random
force. The tails of the velocity gradients probability distribution function
(PDF) are analyzed by saddle-point approximation in the path integral
describing the velocity statistics. The structure of the saddle-point
(instanton), that is velocity field configuration realizing the maximum of
probability, is studied numerically in details. The numerical results allow us
to find analytical solution for the long-time part of the instanton. Its
careful analysis confirms the result of [Phys. Rev. Lett. 78 (8) 1452 (1997)
[chao-dyn/9609005]] based on short-time estimations that the left tail of PDF
has the form ln P(u_x) \propto -|u_x|^(3/2).Comment: 10 pages, RevTeX, 10 figure
Ice giant system exploration in the 2020s:an introduction
The international planetary science community met in London in January 2020, united in the goal of realizing the first dedicated robotic mission to the distant ice giants, Uranus and Neptune, as the only major class of solar system planet yet to be comprehensively explored. Ice-giant-sized worlds appear to be a common outcome of the planet formation process, and pose unique and extreme tests to our understanding of exotic water-rich planetary interiors, dynamic and frigid atmospheres, complex magnetospheric configurations, geologically-rich icy satellites (both natural and captured), and delicate planetary rings. This article introduces a special issue on ice giant system exploration at the start of the 2020s. We review the scientific potential and existing mission design concepts for an ambitious international partnership for exploring Uranus and/or Neptune in the coming decades. This article is part of a discussion meeting issue 'Future exploration of ice giant systems'
Jupiter's temperature structure: a reassessment of the voyager radio occultation results
Stars and planetary system
Time variability of Neptuneâs horizontal and vertical cloud structure revealed by VLT/SINFONI and Gemini/NIFS from 2009 to 2013
Choroid plexus papilloma in a Rottweiler: computed tomographic, gross morfological and histological features
The survival probability of large rapidity gaps in a three channel model
The values and energy dependence for the survival probability of large rapidity gaps (LRG) are calculated in a three channel model. This
model includes single and double diffractive production, as well as elastic
rescattering. It is shown that decreases with increasing
energy, in line with recent results for LRG dijet production at the Tevatron.
This is in spite of the weak dependence on energy of the ratio .Comment: 26 pages in latex file,11 figures in eps file
Survival probability for high mass diffraction
Based on the calculation of survival probabilities, we discuss the problem of
extracting the value of , the triple Pomeron 'bare' coupling constant,
by comparing the large rapidity gap single high mass diffraction data in
proton-proton scattering and photo and DIS production. For p-p
scattering the calculation in a three amplitude rescattering eikonal model,
predicts the survival probability to be an order of magnitude smaller than for
the two amplitude case. The survival probabilities calculation for photo and
DIS production is made in a dedicated model. In this process we show
that, even though its survival probability is considerably larger than in p-p
scattering, its value is below unity and cannot be neglected in the data
analysis. We argue that, regardless of the uncertainties in the suggested
procedure, its outcome is important both with regards to a realistic estimate
of , and the survival probabilities relevant to LHC experiments.Comment: 17 pages, 8 pictures and one tabl
Scientific rationale for Uranus and Neptune <i>in situ</i> explorations
The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising âŒ70% heavy elements surrounded by a more dilute outer envelope of H2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a high-priority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes: i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission
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