Pioneer 10 and 11

The DSN (Deep Space Network) mission support requirements for Pioneer 10 and 11 are summarized. The primary objective of these Pioneer missions is to investigate the interplanetary medium beyond the orbit of Saturn and, in particular, to gather data which may locate the heliopause as these spacecraft cruise out of the solar system to the extreme of their communication capabilities. The mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility

Pioneer 12 (PN-12)

The DSN (Deep Space Network) mission support requirements for Pioneer 12 are summarized. The Pioneer 12 spacecraft is in a 24-hour elliptical orbit around Venus. Atmospheric and altimetry data are obtained mainly around periapsis, and planetary imaging is normally performed around apoapsis. The Pioneer 12 mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility

The Study of the Pioneer Anomaly: New Data and Objectives for New Investigation

Radiometric tracking data from Pioneer 10 and 11 spacecraft has consistently indicated the presence of a small, anomalous, Doppler frequency drift, uniformly changing with a rate of ~6 x 10^{-9} Hz/s; the drift can be interpreted as a constant sunward acceleration of each particular spacecraft of a_P = (8.74 \pm 1.33) x 10^{-10} m/s^2. This signal is known as the Pioneer anomaly; the nature of this anomaly remains unexplained. We discuss the efforts to retrieve the entire data sets of the Pioneer 10/11 radiometric Doppler data. We also report on the recently recovered telemetry files that may be used to reconstruct the engineering history of both spacecraft using original project documentation and newly developed software tools. We discuss possible ways to further investigate the discovered effect using these telemetry files in conjunction with the analysis of the much extended Doppler data. We present the main objectives of new upcoming study of the Pioneer anomaly, namely i) analysis of the early data that could yield the direction of the anomaly, ii) analysis of planetary encounters, that should tell more about the onset of the anomaly, iii) analysis of the entire dataset, to better determine the anomaly's temporal behavior, iv) comparative analysis of individual anomalous accelerations for the two Pioneers, v) the detailed study of on-board systematics, and vi) development of a thermal-electric-dynamical model using on-board telemetry. The outlined strategy may allow for a higher accuracy solution for a_P and, possibly, will lead to an unambiguous determination of the origin of the Pioneer anomaly.Comment: 43 pages, 40 figures, 3 tables, minor changes before publicatio

Pioneer Venus

Venus before Pioneer, the Pioneer Venus mission, Pioneer Venus spacecraft, scientific investigation, mission to Venus scientific results, and results of Soviet studies of Venus are addressed. A chronology of exploration of Venus from Earth before the Pioneer Venus mission and Venus nomenclature and mythology are provided

Using Early Data to Illuminate the Pioneer Anomaly

Analysis of the radio tracking data from the Pioneer 10/11 spacecraft at distances between about 20 - 70 AU from the Sun has consistently indicated the presence of an unmodeled, small, constant, Doppler blue shift drift of order 6 \times 10^{-9} Hz/s. After accounting for systematics, this drift can be interpreted as a constant acceleration of a_P= (8.74 \pm 1.33) \times 10^{-8} cm/s^2 directed towards the Sun, or perhaps as a time acceleration of a_t = (2.92 \pm 0.44)\times 10^{-18} s/s^2. Although it is suspected that there is a systematic origin to this anomaly, none has been unambiguously demonstrated. We review the current status of the anomaly, and then point out how the analysis of early data, which was never analyzed in detail, could allow a more clear understanding of the origin of the anomaly, be it a systematic or a manifestation of unsuspected physics.Comment: 19 pages, 6 figures, 2 tables, additional materia

Space Pioneers and where they are now

A description of the Pioneer project, its history and achievements is given. Major discoveries concerning near and interplanetary space, the planets, and various comets are outlined. Anticipated future observations are considered. A list of Pioneer project launches, 1986 statuses, and project firsts is given

Comma-free Codes Over Finite Alphabets

Comma-free codes have been widely studied in the last sixty years, from points of view as diverse as biology, information theory and combinatorics. We develop new methods to study comma-free codes achieving the maximum size, given the cardinality of the alphabet and the length of the words. Specifically, we are interested in counting the number of such codes. We provide (two different proofs for) a closed-formula. The approach introduced is further developed to tackle well-known sub-families of comma-free codes, such as self-complementary and (generalisations of) non-overlapping codes. We also study codes that are not contained in strictly larger ones. For instance, we determine the maximal size of self-complementary comma-free codes and the number of codes reaching the bound. We provide a characterisation of-letter non-overlapping codes (over an alphabet of cardinality n), which allows us to devise the number of such codes that are not contained in any strictly larger one. Our approach mixes combinatorial and graph-theoretical arguments

Circular Codes in the Genetic Information

Codes are the sets of words over arbitrary alphabets with the property of unique decipherability. Circular codes are a special class of codes. They are the sets of words with the property of unique recognition of the reading frame for any sequence composed of them and written on a circle. They were introduced by Golomb and Gordon in the 60s under the name of codes with bounded synchronization delay, because they have a strong property of synchronization. For this reason, they play an important role in problems of error correction. In the middle 90’s such a circular code X was identified in the genes of bacteria, eukaryotes, plasmids, and viruses by a comprehensive statistical investigation. The code X contained the 20 trinucleotides that appeared to be the codons that had the highest preference for the correct reading frame compared to frames 1 and 2. Since then intensive research on circular codes in the genetic information and their potential role in maintaining the correct reading frame during the translation process in the ribosome has been done by various authors. In particular, X-motifs were identified in (i) genes “universally” (ii) tRNAs of prokaryotes and eukaryotes; (iii) rRNAs of prokaryotes (16S) and eukaryotes (18S), in particular in the ribosome decoding center where the universally conserved nucleotides G530, A1492, and A1493 are included in the X-motif; and (iv) genomes (non-coding regions of eukaryotes). Circular codes have a highly complex structure and the ones found in genes possess additional properties like e.g. self-complementarity that reflect their biological nature. In our talk we give a short introduction to the theory of circular codes and an overview on the methods from mathematics, statistics and bioinformatics to explore their properties and their biological role. Finally, a possible model of the evolution of the genetic code from the perspective of circular code theory is presented.Book of abstract: 4th Belgrade Bioinformatics Conference, June 19-23, 202

Expression of GP73, A Resident Golgi Membrane Protein, in Viral and Nonviral Liver Disease

GP73 is a novel type II Golgi membrane protein of unknown function that is expressed in the hepatocytes of patients with adult giant-cell hepatitis (Gene 2000;249:53-65). Its expression pattern in human liver disease and the regulation of its expression in hepatocytes have not been systematically studied. The aims of the present study were to compare GP73 protein levels in viral and nonviral human liver disease and in normal livers, to identify its cellular sources, and to study the regulation of its expression in hepatoma cells in vitro. GP73 protein levels were quantitated in explant livers of patients with well-defined disease etiologies and compared with the levels in normal donor livers. GP73-expressing cells were identified immunohistochemically. GP73 expression in vitro was studied by Western blotting and immunofluorescence microscopy in HepG2 and SK-Hep-1 cells and in the HepG2-derived, hepatitis B virus (HBV)-transfected HepG2215 and HepG2T14.1 cell lines. Whole organ levels of GP73 were low in normal livers. Significant increases were found in liver disease due to viral causes (HBV, HCV) or nonviral causes (alcohol-induced liver disease, autoimmune hepatitis). In normal livers, GP73 was constitutively expressed by biliary epithelial cells but not by hepatocytes. Hepatocyte expression of GP73 was dramatically up-regulated in diseased livers, regardless of the etiology, whereas biliary epithelial cell expression did not change appreciably. GP73 was present at high levels in HepG2215 cells (a cell line that supports active HBV replication), but was absent in HepG2T14.1 cells (an HBV-transfected cell line that does not support HBV replication) and in HBV-free HepG2 cells. In SK-Hep-1 cells, GP73 expression was increased in response to interferon gamma (IFN-y), and inhibited by tumor necrosis factor x (TNF-x). In conclusion, increased expression of GP73 in hepatocytes appears to be a general feature of advanced liver disease, and may be regulated via distinct pathways that involve hepatotropic viruses or cytokines