scholarly journals The Radio Reference Frame of the U.S. Naval Observatory Radio Interferometry Program

1991 ◽  
Vol 127 ◽  
pp. 256-260 ◽  
Author(s):  
T.M. Eubanks ◽  
M.S. Carter ◽  
F.J. Josties ◽  
D.N. Matsakis ◽  
D.D. McCarthy
Keyword(s):  
Reference Frames ◽  
Dual Frequency ◽  
Source Position ◽  
The Past ◽  
Naval Observatory ◽  
The Difference ◽  
Rotation Of The Earth ◽  
Celestial Reference System ◽  
Right Ascension ◽  
The U.S

AbstractThe U.S. Naval Observatory Navnet program monitors changes in the rotation of the Earth on a regular basis using radio interferometric observations acquired with telescopes in Alaska, Hawaii, Florida, West Virginia and, in the past, Maryland; other radio telescopes have also participated occasionally. These observations have been used to derive a radio interferometric celestial reference system, Navy 1990-5, using two years of dual frequency measurements from 24-hour-duration observing sessions. A total of 84 extragalactic radio sources, mostly quasars, have been observed by the Navnet program to date, of which 70 currently have source position formal errors of one milli second of arc or less. The root mean square of the difference between source position estimates from the Navnet data and an independently derived catalog using completely different data is less than one milli second of arc in both right ascension and declination after the adjustment of an arbitrary rotational offset between the two celestial reference frames.

scholarly journals Astrometry and Geodesy from VLBI

1993 ◽  
Vol 156 ◽  
pp. 159-171
Author(s):  
C. Ma ◽  
J. L. Russell
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Radio Sources ◽  
Dual Frequency ◽  
Terrestrial Reference Frames ◽  
Vlbi Observations ◽  
Using Data ◽  
Celestial Reference Frame ◽  
Right Ascension ◽  
Better Than

Dual frequency Mark III VLBI observations acquired since 1979 by several geodetic and astrometric observing programs have been used to establish precise celestial and terrestrial reference frames. The program to establish a uniformly distributed celestial reference frame of ∼400 compact radio sources with optical counterparts was begun in 1987. Some 700 sources have been considered as part of this effort and a preliminary list of ∼400 has been observed. At present, 308 sources have formal 1σ errors less than 1 mas in right ascension and 308 have similar precision in declination. The astrometric results include some data acquired for geodetic purposes. The geodetic results using data to September, 1992 include the positions of 105 sites with formal 1σ horizontal errors generally less than 1 cm at 1992.6 and the velocities of 64 sites with formal 1σ horizontal errors generally better than 2 mm/yr.

scholarly journals Dense optical reference frames: UCAC and URAT

2007 ◽  
Vol 3 (S248) ◽  
pp. 310-315
Author(s):  
N. Zacharias
Keyword(s):  
Reference Frame ◽  
Focal Plane ◽  
Reference Frames ◽  
Field Of View ◽  
Radio Sources ◽  
Proper Motions ◽  
Naval Observatory ◽  
Optical Reference ◽  
Celestial Reference Frame ◽  
The U.S

AbstractA series of ground-based, dedicated astrometric, observational programs have been performed or are in preparation which provide a dense and accurate optical reference frame. Integral to all these programs are new observations to link the Hipparcos Celestial Reference Frame (HCRF) to the International Celestial Reference Frame (ICRF), based on compact, extragalactic radio sources.The U.S. Naval Observatory CCD Astrograph Catalog (UCAC) 3rd release is in preparation. A pixel re-reduction is in progress to improve astrometric and photometric accuracy as well as completeness of this all-sky reference catalog to 16th magnitude. Optical counterparts of ICRF radio sources have been observed with 0.9-meter telescopes contemporaneously. Scanning of over 5000 early-epoch astrograph plates on StarScan has been completed. These data will improve the proper motions of stars in the 10 to 14 mag range for the UCAC3 release.A 111 million-pixel CCD was successfully fabricated in 2006 and test observations at the USNO astrograph are underway. Four of such detectors will be used for the USNO Robotic Astrometric Telescope (URAT) focal plane assembly. Phase I of URAT will use the astrograph to reach 18th magnitude, while the new 0.85-meter telescope with a 4.5 deg diameter field of view will reach 21st magnitude. The URAT primary mirror has been fabricated.

The Difference That Culture Can Make in End-of-Life Decisionmaking

1998 ◽  
Vol 7 (1) ◽  
pp. 27-40 ◽  
Author(s):  
H. EUGENE HERN ◽  
BARBARA A. KOENIG ◽  
LISA JEAN MOORE ◽  
PATRICIA A. MARSHALL
Keyword(s):  
End Of Life ◽  
Cultural Differences ◽  
Healthcare System ◽  
Cultural Difference ◽  
The Past ◽  
The Difference ◽  
The U.S

Cultural difference has been largely ignored within bioethics, particularly within the end-of-life discourses and practices that have developed over the past two decades in the U.S. healthcare system. Yet how should culture—specifically cultural differences as reflected among groups defined as ethnically or racially different—be taken into account?

scholarly journals Where is the Equinox ?

1979 ◽  
Vol 81 ◽  
pp. 133-143 ◽  
Author(s):  
W. Fricke
Keyword(s):  
The Earth ◽  
Celestial Equator ◽  
The Difference ◽  
Rotation Of The Earth ◽  
The Right ◽  
Important Evidence ◽  
Right Ascension ◽  
Fundamental Reference ◽  
Made In

Within the work being carried out at Heidelberg on the establishment of the new fundamental reference coordinate system, the FK5, the determination of the location of celestial equator and the equinox form an important part. The plane of the celestial equator defined by the axis of rotation of the Earth and the plane of the ecliptic defined by the motion of the Earth about the Sun are both in motion due to various causes. The intersection of the equator and the ecliptic, the dynamical equinox, is therefore in motion. Great efforts have been made in the past to determine the location and motion of the dynamical equinox by means of observations of Sun, Moon and planets in such a manner that the dynamical equinox can serve as the origin of the right ascension system of a fundamental catalogue. The results have not been satisfactory, and we have some important evidence that the catalogue equinox of the FK4 is not identical with the “dynamical equinox”. Moreover, is has turned out that the difference α(DYN) - α(FK4) = E(T) depends on the epoch of observation T. Duncombe et al. (1974) have drawn attention to the possible confusion between the catalogue equinox and dynamical equinox; they mention the difference between two Earth longitude systems, one established by the SAO using star positions on the FK4 and the other one established by the JPL using planetary positions measured from the dynamical equinox. This is undoubtedly one legitimate explanation of the difference, even if other sources of errors may also have contributed.

The U.S. Naval Observatory Automatic Measuring Machines, Present and Future

1971 ◽  
Vol 11 ◽  
pp. 119-121
Author(s):  
K. Aa. Strand
Keyword(s):  
High Speed ◽  
State Of The Art ◽  
Nuclear Research ◽  
Measuring System ◽  
Automatic Measuring ◽  
Design Specifications ◽  
The Past ◽  
Naval Observatory ◽  
Measuring Machine ◽  
The U.S

The automatic measuring machine acquired by the U.S. Naval Observatory in 1966 was built by Nuclear Research Instruments (NRI) in Berkeley, California, based upon design specifications by the Naval Observatory and upon a considerable amount of innovative engineering by NRI. The performance of the machine and the results obtained over the past four years clearly show that a reliable high speed measuring system has been achieved. Hence, when requirements developed for a second machine it was decided to copy the earlier machine, incorporating modifications which the present state of the art permit and which were not available when the machine was designed in 1963.

The 65 cm PZT of the U. S. Naval Observatory

1975 ◽  
Vol 26 ◽  
pp. 309-313
Author(s):  
W. J. Klepczyński
Keyword(s):  
Field Of View ◽  
Proper Motions ◽  
Time Service ◽  
The Earth ◽  
Naval Observatory ◽  
Rotation Of The Earth ◽  
The U.S

AbstractThe Time Service Division of the U.S. Naval Observatory has undertaken a program to construct and install at Washington, D. C. (latitude +39°) a 65 cm photographic zenith tube (PZT) telescope to be used in studies pertaining to the rotation of the Earth. It is expected to improve the precision with which the rate of rotation of the variation of latitude can be determined by photographic techniques and, in addition, will make possible more frequent determinations of these qualities. Due to itp larger field of view, direct intercomparison with the results obtained with other instruments near latitude, +39° will be feasible. Also, it is expected to contribute to studies of the proper motions of stars near declination +39°.

Smart Estimation Ver-H.1.0

2018 ◽  
Author(s):  
Sigit Haryadi
Keyword(s):  
Sample Size ◽  
Confidence Level ◽  
Time Span ◽  
Regression Equation ◽  
Weight Factor ◽  
The Past ◽  
Level Of Confidence ◽  
The Future ◽  
Future Value ◽  
The Difference

We cannot be sure exactly what will happen, we can only estimate by using a particular method, where each method must have the formula to create a regression equation and a formula to calculate the confidence level of the estimated value. This paper conveys a method of estimating the future values, in which the formula for creating a regression equation is based on the assumption that the future value will depend on the difference of the past values divided by a weight factor which corresponding to the time span to the present, and the formula for calculating the level of confidence is to use "the Haryadi Index". The advantage of this method is to remain accurate regardless of the sample size and may ignore the past value that is considered irrelevant.

Novel Drugs and Biologics of 2016: A Boom for Neurodrugs in the Pipelin

2017 ◽  
Vol 10 (5) ◽  
pp. 3809-3814
Author(s):  
D Samba Reddy
Keyword(s):  
Muscular Atrophy ◽  
Clinical Care ◽  
New Drugs ◽  
Essential Medicines ◽  
High Demand ◽  
The Past ◽  
Novel Drugs ◽  
Innovative Products ◽  
Cns Drugs ◽  
The U.S

This article provides a brief overview of novel drugs approved by the U.S. FDA in 2016.  It also focuses on the emerging boom in the development of neurodrugs for central nervous system (CNS) disorders. These new drugs are innovative products that often help advance clinical care worldwide, and in 2016, twenty-two such drugs were approved by the FDA. The list includes the first new drug for disorders such as spinal muscular atrophy, Duchenne muscular dystrophy or hallucinations and delusions of Parkinson’s disease, among several others. Notably, nine of twenty-two (40%) were novel CNS drugs, indicating the industry shifting to neurodrugs. Neurodrugs are the top selling pharmaceuticals worldwide, especially in America and Europe. Therapeutic neurodrugs have proven their significance many times in the past few decades, and the CNS drug portfolio represents some of the most valuable agents in the current pipeline. Many neuroproducts are vital or essential medicines in the current therapeutic armamentarium, including dozens of “blockbuster drugs” (drugs with $1 billion sales potential).  These drugs include antidepressants, antimigraine medications, and anti-epilepsy medications. The rise in neurodrugs’ sales is predominantly due to increased diagnoses of CNS conditions. The boom for neuromedicines is evident from the recent rise in investment, production, and introduction of new CNS drugs.  There are many promising neurodrugs still in the pipeline, which are developed based on the validated “mechanism-based” strategy. Overall, disease-modifying neurodrugs that can prevent or cure serious diseases, such as multiple sclerosis, epilepsy, and Alzheimer’s disease, are in high demand. 

The Future of FBI Counterintelligence through the Lens of the Past Hundred Years

2010 ◽  
pp. 504-517
Author(s):  
Raymond J. Batvinis
Keyword(s):  
United States ◽  
The United States ◽  
Main Concern ◽  
Federal Bureau ◽  
The Past ◽  
Intelligence Services ◽  
Terrorist Groups ◽  
Foreign Intelligence ◽  
Key Events ◽  
The U.S

Counterintelligence is the business of identifying and dealing with foreign intelligence threats to a nation, such as the United States. Its main concern is the intelligence services of foreign states and similar organizations of non-state actors, such as transnational terrorist groups. Counterintelligence functions both as a defensive measure that protects the nation's secrets and assets against foreign intelligence penetration and as an offensive measure to find out what foreign intelligence organizations are planning to defeat better their aim. This article addresses the Federal Bureau of Investigation's (FBI) foreign counterintelligence function. It briefly traces its evolution by examining the key events and the issues that effected its growth as the principle civilian counterintelligence service of the U.S. government.

Eve Kosofsky Sedgwick and the difference geography makes

2021 ◽  
Vol 11 (1) ◽  
pp. 117-121 ◽  
Author(s):  
David K Seitz
Keyword(s):  
Time And Space ◽  
Textual Practice ◽  
Reparative Reading ◽  
The Difference ◽  
The U.S ◽  
Eve Kosofsky Sedgwick

Ruez and Cockayne point out that queer theorist Eve Sedgwick’s reflections on paranoid and reparative readings accompanying one another came directly out of her queer political as well as textual practice in the U.S. Wrongly dismissed as mundane, this crucial contextualizing work is something geographers do especially well. Indeed, understanding the context for Sedgwick’s theories of paranoid and reparative reading is vital as we reflect on how her concepts travel across time and space.

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