Extreme TGF Imaging by ASIM

2020 ◽  
Author(s):  
Víctor Reglero ◽  
Paul Connell ◽  
Javier Navarro ◽  
Christopher Eyles ◽  
Nikolai Ostgaard ◽  
...  
Keyword(s):  
Convective Cell ◽  
Imaging Data ◽  
Source Imaging ◽  
Extended Source ◽  
The Earth ◽  
Operational Phase ◽  
One Year ◽  
Asymmetric Matter ◽  
Imaging Conditions ◽  
Accurate Imaging

<p>One year after the starting of ASIM operational phase, we have succeeded to perform accurate Imaging of 54 TGF.  Among them, some have been analysed at extreme imaging conditions in terms of TGF position at the MXGS partially coded field of view.  20 TGF events have angular distances larger than 40º respect to the MXGS FOV centre. Extreme cases at angular distances larger than 50º are presented. Validation of TGF position by WLN data is included in the discussion.</p><p>The canonical value of 32 LED cnts as the minimum fluency for TGF imaging defined during MXGS development was checked using low luminosity TGF.  At the present, we have succeeded to obtain imaging solution for 7 TGF with less than 20 cnts. A sample is presented with indication of position accuracy and S/N ratios.  </p><p>Last part of the presentation is the discussion of a TGF with a very large and asymmetric probability distribution at the MXGS FOV that suggest the TGF as an extended source. Imaging data projected to the Earth surface is compared with GOES data, showing that the TGF is at the edge of a large convective cell, close to the TGF imaging data map.  Therefore, we can conclude that for some bright TGF it is possible to estimate the TGF fireball dimensions generated by the iteration of TGF photons with local atmospheric asymmetric matter distributions. The presence of a large CZT tail is coherent with the size of the convective cell.</p>

Preliminary monthly gravity field models from kinematic orbits of SWARM Satellites

2021 ◽  
Author(s):  
Xingfu Zhang ◽  
Qiujie Chen ◽  
Yunzhong Shen
Keyword(s):  
Gravity Field ◽  
Large Scale ◽  
Earth System ◽  
The Earth ◽  
Swarm Satellites ◽  
Variable Gravity ◽  
Data Gap ◽  
One Year ◽  
Gravity Recovery ◽  
Gravity Field Models

<p>      Although the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE FO) satellite missions play an important role in monitoring global mass changes within the Earth system, there is a data gap of about one year spanning July 2017 to May 2018, which leads to discontinuous gravity observations for monitoring global mass changes. As an alternative mission, the SWARM satellites can provide gravity observations to close this data gap. In this paper, we are dedicated to developing alternative monthly time-variable gravity field solutions from SWARM data. Using kinematic orbits of SWARM from ITSG for the period January 2015 to September 2020, we have generated a preliminary time series of monthly gravity field models named Tongji-Swarm2019 up to degree and order 60. The comparisons between Tongji-Swarm2019 and GRACE/GRACE-FO monthly solutions show that Tongji-Swarm2019 solutions agree with GRACE/GRACE-FO models in terms of large-scale mass change signals over amazon, Greenland and other regions. We can conclude that Tongji-Swarm2019 monthly gravity field models are able to close the gap between GRACE and GRACE FO.</p>

scholarly journals COASTAL APPLICATIONS OF THE ERTS-A SATELLITE

1972 ◽  
Vol 1 (13) ◽  
pp. 113
Author(s):  
Orville T. Magoon ◽  
Douglas M. Pirie ◽  
John W. Jarman
Keyword(s):  
Multispectral Images ◽  
Precise Location ◽  
Multispectral Data ◽  
Topographic Features ◽  
Efficient Management ◽  
The Earth ◽  
Maximum Utility ◽  
Data Output ◽  
Constant Observation ◽  
One Year

This paper describes the Earth Resources Technology Satellite (ERTS) placed in orbit in July 1972 and the ERTS simulation high altitude aircraft flights which have been flown for approximately one year. The ERTS satellite and simulation programs conducted by the National Aeronautics and Space Administration (NASA) have been developed to demonstrate the techniques for efficient management of the earth's resources. To achieve this objective the ERTS-A satellite provides for the repetitive acquisition of high resolution multispectral data of the earth's surface on a global basis. Two sensor systems have been selected for this purpose: a fourchannel multispectral scanner (MSS) subsystem for ERTS-A and a threecamera return beam vidicon (RBV) system. Systematic repeating earth coverage under nearly constant observation conditions is provided for maximum utility of the multispectral images collected by the ERTS satellite, which operates in a circular sun synchronous nearly polar orbit at an altitude of 494 nautical miles. It circles the earth every 103 minutes completing 14 orbits per day and views the entire earth in 18 days. The orbit has been selected so that the satellite ground trace repeats its earth coverage at the same local time every 18-day period within 20 nautical miles. A number of data output products are available from this satellite which include 70 mm products for precise location of topographic features, 9.5 inch positive or paper prints and also computer compatible tapes or punched cards. Also described are the results of the ERTS-A simulation flights flown at an altitude of 65,000 feet as related to coastal studies. Simulations of both the RBV and MSS in coastal areas are presented.

Theories of Polar Motion from Tisserand to Poincaré (1890 – 1910)

2000 ◽  
Vol 178 ◽  
pp. 41-66 ◽  
Author(s):  
P. Melchior
Keyword(s):  
Polar Motion ◽  
Scientific Community ◽  
Circular Motion ◽  
Computing Power ◽  
The Earth ◽  
Fixed Pole ◽  
One Year ◽  
Elliptical Motion ◽  
The Impact ◽  
Chandler Period

AbstractThe discovery by Seth C. Chandler (1891) that the motion of the pole (the reality of which had been established by K.F. Küstner and by the simultaneous latitude observations at Honolulu and Berlin by German astronomers) resulted from two components i.e. a free circular motion with a period of 427 days and a forced elliptical motion with a period of 365.25 days, raised considerable interest in the scientific community of astronomers and geophysicists.The celebrated Mécanique Céleste of Tisserand (1890) had been published just one year before at a time when doubts still persisted and arguments could be presented in favor of the fixed pole. Starting with Tisserand’s arguments, we describe in this paper the impact of the successive contributions by A. Greenhill, S. Newcomb, Th. Sloudsky, S. Hough, G. Herglotz, A. Love, J. Larmor and H. Poincaré to the solution of the problems raised by the Chandler period.The lines of reasoning taken by these eminent scientists were rigorously correct so that, after about one hundred years, contemporary researchers, who benefit from a far better knowledge of the inner structure of the Earth and are able to take advantage of modern computing power, do not contradict any of their conclusions and instead refine them with an accuracy which was not imaginable one century ago.

scholarly journals VLBI studies of the nutations of the earth

1988 ◽  
Vol 129 ◽  
pp. 371-375
Author(s):  
T. A. Herring
Keyword(s):  
Truncation Error ◽  
Very Long Baseline Interferometry ◽  
Long Baseline ◽  
The Earth ◽  
Vlbi Data ◽  
One Year ◽  
Nutation Series ◽  
Theoretical Considerations ◽  
Active Investigation

The application of very–long–baseline interferometry (VLBI) to the study of the nutations of the earth has yielded unprecedented accuracy for the experimental determination of the coefficients of the nutation series. The analysis of six years of VLBI data has yielded corrections to the coefficients of the seven largest terms in the IAU 1980 nutation series with periods of one year or less, with accuracies approaching the truncation error of this nutation series (0.1 mas). The nutation series coefficients computed from the VLBI data, and those obtained from theoretical considerations (the IAU 1980 nutation series), are in excellent agreement. The largest corrections are to the coefficients of the retrograde annual nutation [2.0 ± 0.1 mas], the prograde semiannual nutation [(0.5 - ι 0.4) ±0.1 mas], and the prograde 13.7 day nutation [−0.4 ± 0.1 mas]. (The imaginary term for the semiannual nutation represents a term 90° out–of–phase with the arguments of the nutation series.) The geophysical implications of these results are currently under active investigation. We discuss the methods used to extract the nutation information from the VLBI data, the calculations of the uncertainties of the resultant corrections to the coefficients of the nutation series, and the current research into the nutations of the earth.

Indigenous Qualitative Inquiry

2012 ◽  
Vol 5 (1) ◽  
pp. 51-72 ◽  
Author(s):  
Marcelo Diversi ◽  
Dan Henhawk
Keyword(s):  
Indigenous Peoples ◽  
Knowledge Production ◽  
Ethical Issues ◽  
Ways Of Knowing ◽  
Qualitative Inquiry ◽  
The Earth ◽  
First Arrival ◽  
One Year ◽  
Interpretive Communities

Five centuries after the first arrival of European settlers in what they called the Americas, indigenous peoples and ways of knowing continue to be largely represented and reified by Western scholars and epistemologies. We argue here that, even within Qualitative Inquiry and its critical paradigms and theories, indigenous bodies and narratives continue to be relatively scarce as our interpretive communities attempt to advance decolonizing knowledge production, pedagogy, and praxis. In this article, we argue that this persistent segregation is related to an academic structure that continues to privilege Western paradigms (e.g., theoretical sophistication over visceral knowledge of oppression) and ways of knowing (e.g., reductionist binary definitions of indigeneity still too obsessed with authenticity). The center-piece of our article and critique is an email exchange between the authors about ontological, epistemological, and ethical issues of indigenous qualitative inquiry over the period of one year. We attempt to use our exchange as an instantiation—a textual, intellectual, and emotional performance—of ontological questions on indigenous qualitative inquiry: Who is indigenous? Are there common grounds among indigenous peoples of the earth? And if so, can we find more effective ways to gather in these common grounds in the 21st century? We conclude by offering our own suggestions toward decolonizing imaginations and praxis.

Abstract WP420: Clopidogrel with Aspirin May be More Effective in Decreasing One-year Stroke Recurrence for Acute Minor Stroke with Watershed Infarcts: Subgroup Analysis of Chance

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Yuehua Pu ◽  
Liping Liu ◽  
Yilong Wang ◽  
Jing Jing ◽  
Anxin Wang ◽  
...  
Keyword(s):  
High Risk ◽  
Mr Imaging ◽  
Antiplatelet Therapy ◽  
Dual Antiplatelet Therapy ◽  
Minor Stroke ◽  
Stroke Recurrence ◽  
Imaging Data ◽  
Stroke Patients ◽  
One Year ◽  
Watershed Infarcts

Background and Objective: In symptomatic cerebral large artery disease, watershed infarcts may result from hemodynamic impairment or microembolism. Such patients often have a high risk of recurrence or deterioration. It is still not clear whether dual antiplatelet therapy reduce the risk of stroke recurrence. The aim of this subgroup analysis is to discuss whether dual antiplatelet therapy could decrease the one year stroke recurrence more effectively for minor stroke patients with watershed infarcts. Methods: Patients enrolled in Clopidogrel in High-risk patients with Acute Non-disabling Cerebrovascular Events (CHANCE) trial and have magnetic resonance (MR) imaging data were included in this study. Diffusion-weighted imaging was obtained for detection of watershed infarcts. We assessed the interaction of the treatment effects of clopidogrel plus aspirin versus aspirin alone among patients with watershed infarcts or not. Results: Of the 1089 patients with MR imaging data enrolled in the CHANCE trial, 831 (76.3%) patients with acute infarcts. Among patients with acute infarcts, 93 (11.19%) were watershed infarcts, 55 (59.14%) received dual antiplatelet therapy. Patients with watershed infarcts had higher rates of recurrent stroke (17.20% vs 10.70%, p=0.063) at 1 year. For patients with watershed infarcts, one-year stroke recurrence was 6 (10.91%) in clopidogrel plus aspirin group and 10 (26.32%) in placebo plus aspirin group. There was interaction between antiplatelet therapy and presence of watershed infarcts on the primary outcome of any stroke (p=0.0933). (Kaplan-Meier curves were showed in the figure). Conclusions: For minor stroke patients with watershed infarcts, clopidogrel with aspirin may be more effective in decreasing 1-year stroke recurrence attributed to its potential mechanism of microembolism. Studies in other populations and subsequent analysis with adequate power are warranted to further verify such findings.

scholarly journals The current status of the Nano-JASMINE project

2007 ◽  
Vol 3 (S248) ◽  
pp. 270-271 ◽  
Author(s):  
Y. Kobayashi ◽  
N. Gouda ◽  
T. Yano ◽  
M. Suganuma ◽  
M. Yamauchi ◽  
...  
Keyword(s):  
Processing System ◽  
Thermal Stabilization ◽  
Image Data ◽  
Current Status ◽  
Imaging Data ◽  
Fully Depleted ◽  
Beam Combiner ◽  
One Year ◽  
Aluminum Beam ◽  
Stellar Image

AbstractNano-JASMINE is a nano-size astrometry satellite that will carry out astrometry measurements of nearby bright stars for more than one year. This will enable us to detect annual parallaxes of stars within 300 pc from the Sun. We expect the satellite to be launched as a piggy-back system as early as in 2009 into a Sun synchronized orbit at the altitude between 500 and 800 km. Being equipped with a beam combiner, the satellite has a capability to observe two different fields simultaneously and will be able to carry out HIPPARCOS-type observations along great circles. A 5 cm all aluminum made reflecting telescope with a aluminum beam combiner is developed. Using the on-board CCD controller, experiments with a real star have been executed. A communication band width is insufficient to transfer all imaging data, hence, we developed an onboard data processing system that extracts stellar image data from vast amount of imaging data. A newly developed 2K × 1K fully-depleted CCD will be used for the mission. It will work in the time delayed integration(TDI) mode. The bus system has been designed with special consideration of the following two points. Those are the thermal stabilization of the telescope and the accuracy of the altitude control. The former is essential to achieve high astrometric accuracies, on the order of 1 mas. Therefore relative angle of the beam combiner must be stable within 1 mas. A 3-axes control of the satellite will be realized by using fiber gyro and triaxial reaction wheel system and careful treatment of various disturbing forces.

scholarly journals Vol-PACT: A Foundation for the NIH Public-Private Partnership That Supports Sharing of Clinical Trial Data for the Development of Improved Imaging Biomarkers in Oncology

2018 ◽  
pp. 1-12 ◽  
Author(s):  
Laurent Dercle ◽  
Dana E. Connors ◽  
Ying Tang ◽  
Stacey J. Adam ◽  
Mithat Gönen ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Solid Tumors ◽  
Randomized Trials ◽  
Public Private Partnership ◽  
Imaging Data ◽  
Source Imaging ◽  
New Approach ◽  
Private Partnership ◽  
End Point ◽  
Computed Tomography Scans

Purpose To develop a public-private partnership to study the feasibility of a new approach in collecting and analyzing clinically annotated imaging data from landmark phase III trials in advanced solid tumors. Patients and Methods The collection of clinical trials fulfilled the following inclusion criteria: completed randomized trials of > 300 patients, highly measurable solid tumors (non–small-cell lung cancer, colorectal cancer, renal cell cancer, and melanoma), and required sponsor and institutional review board sign-offs. The new approach in analyzing computed tomography scans was to transfer to an academic image analysis laboratory, draw contours semi-automatically by using in-house–developed algorithms integrated into the open source imaging platform Weasis, and perform serial volumetric measurement. Results The median duration of contracting with five sponsors was 12 months. Ten trials in 7,085 patients that covered 12 treatment regimens across 20 trial arms were collected. To date, four trials in 3,954 patients were analyzed. Source imaging data were transferred to the academic core from 97% of trial patients (n = 3,837). Tumor imaging measurements were extracted from 82% of transferred computed tomography scans (n = 3,162). Causes of extraction failure were nonmeasurable disease (n = 392), single imaging time point (n = 224), and secondary captured images (n = 59). Overall, clinically annotated imaging data were extracted in 79% of patients (n = 3,055), and the primary trial end point analysis in each trial remained representative of each original trial end point. Conclusion The sharing and analysis of source imaging data from large randomized trials is feasible and offer a rich and reusable, but largely untapped, resource for future research on novel trial-level response and progression imaging metrics.

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