scholarly journals Global astrometric sphere reconstruction in Gaia: challenges and first results of the Verification Unit

2009 ◽  
Vol 5 (S261) ◽  
pp. 337-341
Author(s):  
Alberto Vecchiato ◽  
Ummi Abbas ◽  
Beatrice Bucciarelli ◽  
Mario G. Lattanzi ◽  
Roberto Morbidelli
Keyword(s):  
General Relativity ◽  
Data Processing ◽  
Data Reduction ◽  
Systematic Errors ◽  
History Of Astronomy ◽  
The Core ◽  
Significant Difference ◽  
First Results ◽  
History Of ◽  
Absolute Measurements

AbstractGaia will estimate the astrometric and physical data of approximately one billion objects. The core of this process, the global sphere reconstruction, is represented by the reduction of a subset of these objects, which will constitute the largest and most precise catalog of absolute astrometry in the history of Astronomy, and will put General Relativity to test by estimating the PPN parameter γ with unprecedented accuracy. As the Hipparcos mission showed, and as it is natural for all kind of absolute measurements, possible errors in the data reduction can hardly be identified at the end of the processing, and can lead to systematic errors in all the works which will use these results. In order to avoid such kind of problems, a Verification Unit was established by the Gaia Data Processing and Analysis Consortium (DPAC). One of its jobs is to implement and perform an independent global sphere reconstruction, parallel to the baseline one, to compare the two results, and to report any significant difference.

scholarly journals The global sphere reconstruction (GSR)

2018 ◽  
Vol 620 ◽  
pp. A40
Author(s):  
A. Vecchiato ◽  
B. Bucciarelli ◽  
M. G. Lattanzi ◽  
U. Becciani ◽  
L. Bianchi ◽  
...  
Keyword(s):  
Data Reduction ◽  
Simulated Data ◽  
Real Data ◽  
Iterative Solution ◽  
Lessons Learned ◽  
Reconstruction Method ◽  
History Of Astronomy ◽  
Software Modules ◽  
History Of ◽  
Absolute Measurements

Context.TheGaiaESA mission will estimate the astrometric and physical data of more than one billion objects, providing the largest and most precise catalog of absolute astrometry in the history of astronomy. The core of this process, the so-called global sphere reconstruction, is represented by the reduction of a subset of these objects which will be used to define the celestial reference frame. As the HIPPARCOSmission showed, and as is inherent to all kinds of absolute measurements, possible errors in the data reduction can hardly be identified from the catalog, thus potentially introducing systematic errors in all derived work.Aims.Following up on the lessons learned from HIPPARCOS, our aim is thus to develop an independent sphere reconstruction method that contributes to guarantee the quality of the astrometric results without fully reproducing the main processing chain.Methods.Indeed, given the unfeasibility of a complete replica of the data reduction pipeline, an astrometric verification unit (AVU) was instituted by theGaiaData Processing and Analysis Consortium (DPAC). One of its jobs is to implement and operate an independent global sphere reconstruction (GSR), parallel to the baseline one (AGIS, namely Astrometric Global Iterative Solution) but limited to the primary stars and for validation purposes, to compare the two results, and to report on any significant differences.Results.Tests performed on simulated data show that GSR is able to reproduce at the sub-μas level the results of the AGIS demonstration run.Conclusions.Further development is ongoing to improve on the treatment of real data and on the software modules that compare the AGIS and GSR solutions to identify possible discrepancies above the tolerance level set by the accuracy of theGaiacatalog.

Covered with Deep Mist

2020 ◽  
Author(s):  
Dean Rickles
Keyword(s):  
General Relativity ◽  
Quantum Gravity ◽  
Unresolved Problem ◽  
The Core ◽  
Modern Physics ◽  
Technical Examination ◽  
History Of ◽  
Theory Of Gravitation ◽  
Under Construction ◽  
Social And Cultural Factors

The problem of quantum gravity is often viewed as the most pressing unresolved problem of modern physics, the ‘holy grail’: our theories of spacetime and matter, described respectively by general relativity (Einstein’s theory of gravitation and spacetime) and quantum mechanics (our best theory of matter and the other forces of nature) resist unification. Covered in Deep Mist provides the first book-length treatment of the history of quantum gravity, focusing on its origins and earliest stages of development until the mid-1950s. Readers will be guided through the impacts on the problem of quantum gravity resulting from changes in the two ingredient theories, quantum theory and general relativity, which were themselves still under construction in the years studied. We examine how several of the core approaches of today were formed in an era when the field was highly unfashionable. The book aims to be accessible to a broad range of readers and goes beyond a merely technical examination to include social and cultural factors involved in the changing fortunes of the field. Suitable for both newcomers and seasoned quantum gravity professionals, the book will shine new light on this century old, unresolved problem.

First Results of the 2019 Algerian Magnetic Repeat Station Network

2020 ◽  
Author(s):  
Abdenacuer Lemgharbi ◽  
Abdeslam Abtout ◽  
Mohamed Hamoudi ◽  
Abdelhamid Bendekken ◽  
Fatma Annad ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Station Network ◽  
Repeat Station ◽  
First Results ◽  
Geomagnetic Field Models ◽  
Polynomial Modeling ◽  
History Of ◽  
Absolute Measurements

<p><strong>Abstract:</strong></p><p>The second part of the history of the Algerian magnetic repeat station network goes back to 1989 when the new one was started with 37 stations. It was then followed by three other networks in 1993, 1997 and 2005. The first part of this history started at the beginning of the XX<sup>th</sup> and ended ca 1956.</p><p>After a 14-year break, we launched a new repeat stations network in February 2019. The number of carried out stations was increased to 51 to try to cover all the territory.</p><p>Each repeat station network consists of stations of periodically, say  5-6 years, measured of three components of the Earth's magnetic field. to try to derive the spatial distribution of the geomagnetic field of Algeria and it's secular variation. This periodicity is also very important for the need to update local as well as global geomagnetic field models such as the International Geomagnetic Reference Field (IGRF).</p><p>In this work we describe the new 2019 Algerian repeat station network. Then we will discuss the steps of the absolute measurements using two methods. The first one is called the ‘method of zero’ and the second one ‘method of residuals’. The accuracy and resolution of the instruments and data reduction used and their effect on the final results will as well be discussed. We derive the spatial distribution of the geomagnetic field, and its secular variation. Finally, we will show how local, for instance regional polynomial modeling, is the key issue.</p><p><strong>Key words</strong>: geomagnetic repeat network, absolute measurements, zero method, residual method, magnetic maps of Algeria, secular variation.</p>

Factor V Leiden Is Associated with Repeated and Recurrent Unexplained Fetal Losses

1997 ◽  
Vol 77 (05) ◽  
pp. 0822-0824 ◽  
Author(s):  
Elvira Grandone ◽  
Maurizio Margaglione ◽  
Donatella Colaizzo ◽  
Marina d'Addedda ◽  
Giuseppe Cappucci ◽  
...  
Keyword(s):  
Protein C ◽  
Strong Association ◽  
Activated Protein C ◽  
Fetal Loss ◽  
Factor V Leiden ◽  
Factor V ◽  
Significant Difference ◽  
History Of ◽  
Fv Leiden ◽  
Caucasian Women

SummaryActivated protein C resistance (APCR) is responsible for most cases of familial thrombosis. The factor V missense mutation Arg506>Gln (FV Leiden) has been recognized as the commonest cause of this condition. Recently, it has been suggested that APCR is associated with second trimester fetal loss. We investigated the distribution of FV Leiden in a sample (n = 43) of Caucasian women with a history of two or more unexplained fetal losses. A group (n = 118) of parous women with uneventful pregnancies from the same ethnical background served as control. We found the mutation in 7 cases (16.28%) and 5 controls (4.24%; p = 0.011). A statistically significant difference between women with only early fetal loss vs those with late events (p = 0.04) was observed. Our data demonstrate a strong association between FV Leiden and fetal loss. Furthermore, they indicate that late events are more common in these patients.

PCR-RFLP Detection od PAI-2 Gene Variants: Prevelence in Ethnic Groups and Disease Relationship in patients Undergoing corony Angiography

1997 ◽  
Vol 77 (05) ◽  
pp. 0955-0958 ◽  
Author(s):  
Carole A Foy ◽  
Peter J Grant
Keyword(s):  
Gene Variants ◽  
Genotype Distribution ◽  
Pima Indians ◽  
Significant Difference ◽  
Pcr Rflp ◽  
History Of ◽  
Caucasian Patients ◽  
Clinical Conditions ◽  
Rflp Assay ◽  
Coronary Atheroma

SummaryPAI-2 is a fibrinolytic inhibitor produced predominantly by monocytes. Most PAI-2 is intracellular making study in clinical conditions difficult. Abnormalities in production may be associated with inflammation and fibrinolysis at sites of tissue damage such as the atherosclerotic plaque.PAI-2 gene variants have been described: variant A consists of Asn120, Asn404 and Ser413 and variant B consists of Asp120, Lys404 and Cys413. We designed a PCR-RFLP assay using primers spanning the region containing Asn/Lys404 and Ser/Cys413. Variant B contains an Mwol restriction site. We analysed 302 Pima Indians and 286 healthy Caucasian volunteers. To investigate relationships between genotype and vascular disease we analysed 333 Caucasian patients undergoing coronary angiography.Gene variant B was more common in the Pimas than in Caucasians (p <0.0001). There was no significant difference in genotype distribution between the volunteers and patients. In the patients there was no association between genotype and either a history of MI or extent of coronary atheroma.

Materials for the history of the gospel-Baptist movement in Ukraine

1996 ◽  
pp. 4-15
Author(s):  
S. Golovaschenko ◽  
Petro Kosuha
Keyword(s):  
Large Scale ◽  
Religious Studies ◽  
Theological Seminary ◽  
National Academy Of Sciences ◽  
Evangelical Christians ◽  
Evangelical Christian ◽  
First Results ◽  
History Of ◽  
Fruitful Cooperation ◽  
Academy Of Sciences

The report is based on the first results of the study "The History of the Evangelical Christians-Baptists in Ukraine", carried out in 1994-1996 by the joint efforts of the Department of Religious Studies at the Institute of Philosophy of the National Academy of Sciences of Ukraine and the Odessa Theological Seminary of Evangelical Christian Baptists. A large-scale description and research of archival sources on the history of evangelical movements in our country gave the first experience of fruitful cooperation between secular and church researchers.

From Dust to Life

2017 ◽  
Author(s):  
John Chambers ◽  
Jacqueline Mitton
Keyword(s):  
Solar System ◽  
Extrasolar Planets ◽  
Planetary Systems ◽  
History Of Astronomy ◽  
Human Origins ◽  
History Of ◽  
The Subject ◽  
Emergence Of Life

The birth and evolution of our solar system is a tantalizing mystery that may one day provide answers to the question of human origins. This book tells the remarkable story of how the celestial objects that make up the solar system arose from common beginnings billions of years ago, and how scientists and philosophers have sought to unravel this mystery down through the centuries, piecing together the clues that enabled them to deduce the solar system's layout, its age, and the most likely way it formed. Drawing on the history of astronomy and the latest findings in astrophysics and the planetary sciences, the book offers the most up-to-date and authoritative treatment of the subject available. It examines how the evolving universe set the stage for the appearance of our Sun, and how the nebulous cloud of gas and dust that accompanied the young Sun eventually became the planets, comets, moons, and asteroids that exist today. It explores how each of the planets acquired its unique characteristics, why some are rocky and others gaseous, and why one planet in particular—our Earth—provided an almost perfect haven for the emergence of life. The book takes readers to the very frontiers of modern research, engaging with the latest controversies and debates. It reveals how ongoing discoveries of far-distant extrasolar planets and planetary systems are transforming our understanding of our own solar system's astonishing history and its possible fate.

Breastfeeding Training through Role-Play and Effects on Mother-infant Attachment Behaviours: A Randomised Controlled Trial

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Farokh Saljughi ◽  
Mitra Savabi-Esfahani ◽  
Shahnaz Kohan ◽  
Soheila Ehsanpour
Keyword(s):  
Pregnant Women ◽  
Maternal Employment ◽  
Controlled Trial ◽  
Role Play ◽  
Intervention Group ◽  
Control Group ◽  
Maternal Behaviour ◽  
Infant Attachment ◽  
Significant Difference ◽  
History Of

Mother-infant attachment is an intimate, lasting and satisfying relationship that leads to better cognitive, emotional and social growth of the infant. The aim of this study was to determine the effects of breastfeeding training by role-play on mother-infant attachment behaviours. This research was a randomised clinical trial (parallel design). Inclusion criteria were: no history of mental disorders; ability to read and write the Persian language to complete the questionnaire; no history of drug and tobacco intake in primigravida women. The sample comprised 100 pregnant women (in 2 groups), selected through simple random sampling at healthcare centres. The researcher reviewed prenatal care registries of selected healthcare centres and extracted the names of pregnant women in their early third trimester. The data were imported into randomisation software. The control group received routine breastfeeding training, while the intervention group received routine training together with training through role-play. The data collection tool was the Maternal Behaviour Inventory Questionnaire. Consequently 75 samples were analysed in SPSS16. Independent t-tests and chi-square tests were used to examine the difference between the two groups. Results showed that the mean score of mother-infant attachment one week after delivery was significantly higher in the intervention group in comparison to that in the control group (p<0.001). No significant difference was observed between the two groups in maternal age, age of marriage, neonatal gender, maternal employment and education, number of parity, and number of abortions (P>0.05). Since breastfeeding training through role-play could affect mother-infant attachment, it is suggested that this type of training should be provided for pregnant women to promote mother-infant attachment and exclusive breastfeeding.

THE CORE AND PERIPHERY OF THE CURRENT CULTURE OF ARTISTIC CREATION ABOUT THE GREAT PATRIOTIC WAR IN THE STUDENTS’ VIEWS

2020 ◽  
Vol 6 (3) ◽  
pp. 130-149
Author(s):  
Elena N. NARKHOVA ◽  
Dmitry Yu. NARKHOV
Keyword(s):  
Historical Memory ◽  
Soviet Period ◽  
Russian Society ◽  
Student Culture ◽  
The Core ◽  
Musical Works ◽  
Great Patriotic War ◽  
History Of ◽  
Current Student ◽  
Historical Periods

This article analyzes the degree of demand for works of art (films and television films and series, literary and musical works, works of monumental art) associated with the history of the Great Patriotic War among contemporary students. This research is based on the combination of two theories, which study the dynamics and statics of culture in the society — the theory of the nucleus and periphery by Yu. M. Lotman and the theory of actual culture by L. N. Kogan. The four waves of research (2005, 2010, 2015, 2020) by the Russian Society of Socio¬logists (ROS) have revealed a series of works in various genres on this topic in the core structure and on the periphery of the current student culture; this has also allowed tracing the dynamics of demand and the “movement” of these works in the sociocultural space. The authors introduce the concept of the archetype of the echo of war. The high student recognition of works of all historical periods (from wartime to the present day) is shown. A significant complex of works has been identified, forming two contours of the periphery. Attention is drawn to the artistic work of contemporary students as a way to preserve the historical memory of the Great Patriotic War. This article explains the necessity of preserving the layer of national culture in order to reproduce the national identity in the conditions of informational and ideological pluralism of the post-Soviet period. The authors note the differentiation of youth due to the conditions and specifics of socialization in the polysemantic sociocultural space.

Kant and extragalactic revolution in astronomy

2004 ◽  
Vol 47 (1-2) ◽  
pp. 95-109
Author(s):  
Milan Cirkovic
Keyword(s):  
History Of Astronomy ◽  
Physical Universe ◽  
History Of ◽  
Island Universes

In this paper we briefly consider the role Kant's early philosophy, and notably his "island universes" hypothesis played in the history of astronomy. There are many reasons for this, including the coincidence of Kant's jubilee year with 80 years since Hubble's discovery (1924) of the extragalactic universe. This discovery, confirming the "island universes" hypothesis revolutionized our picture of the physical universe. Prehistory of this revolution has another aspect, apart from the historical one, of significance for philosophy: it presents one of the best supported and empirically documented instances of the application of the Duhem-Quine thesis on subdetermination of theory by experiments.

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