Ninety day mission report for Skylab experiment T025

The problems encountered in the observing programs using the airlock coronagraph (T025) are reported for the atmospheric scattering program, Kohoutek photography, and the spacecraft contamination analysis. The impact of the difficulties on the results is discussed

Skylab contamination results: S052 particle analysis and T025 analysis

The size and velocity distributions of 500 contaminant particles in the near environs of Skylab were determined from video tape data obtained by the high altitude observatory's white light coronagraph. A complete listing of derived particle parameters, their frequency distributions, and their behavior as a function of time are presented. A correlation between particle size and velocity is noted, and at least two prominent directions of the particle spacecraft origins are identified

Preliminary study of contaminant particulates around Skylab

Techniques originally developed for the Skylab T025 contamination experiment were applied to S052 white-light coronagraph data in a preliminary study to investigate particulates around Skylab. Periods were selected which contained some contamination, even though there were no apparent dumps or vents during these periods. Velocity and size distributions were determined from optical data for particles within 200 meters of the spacecraft. Both photographic (61 particle tracks) and video (34 particles) observations yield an upper limit on particle radius of 100 micrometers. Selected photometric data from the S073 zodiacal light experiment during mission SL-2 were also examined for evidence of contamination

Exploration of the influence of 5-iodo-2'-deoxyuridine incorporation on the structure of d[CACG(IDU)G]

The first antiviral nucleoside 5-iodo-2'-deoxyuridine (IDU) against herpes simplex virus type 1 and type 2 is a thymidine analogue, i.e. the C5 methyl group is replaced by an I atom. The structure of the self-complementary hexamer d[CACG(IDU)G] was determined by single-crystal X-ray diffraction techniques. The orthorhombic crystals belong to space group P2(1)2(1)2(1), with unit-cell parameters a = 18.16, b = 30.03, c = 41.99 Angstrom. Refinement in the resolution range 20 - 1.3 Angstrom converged with a final R1 = 0.167, including 43 water molecules and two cobalt hexammine complexes. The incorporation of a large I atom has only minor consequences for the overall structure as is noticed in the IDU . A base pairs, which are of the common Watson - Crick type. To contribute to the still puzzling mechanism of this historically important agent, details of base stacking, helical parameters, hydration etc. have been studied. A general scheme of cobalt hexammine-binding modes in Z-DNA is provided, revealing similar binding modes for the reported structure

Synthesis and Characterization of Gold, Silver, and Copper Cluster Compounds.

Seven new coinage metal cluster compounds were synthesized and their single-crystal X-ray structures were determined. The novel gold cluster, hexakis(o-methyldithiobenzoato)hexagold(I), (Au\sb6 (o-CH\sb3C\sb6H\sb4CS\sb2)\sb6), has six gold atoms that are coplanar to within 0.14A. Each gold(I) forms two nearly linear bonds to bridging ligands alternately above and below the cluster plane. In addition to the multitude of Au-Au interactions within the hexameric cluster, a close intermolecular contact exists, thereby forming chains of these hexamers. The other gold cluster is a dimer, bis(2,4,6-trimethyldithiobenzoato)digold(I), (Au\sb2\{2,4,6-(CH\sb3)\sb3C\sb6H\sb2CS\sb2\}\sb2). However, there are three crystallographically independent dimers in the unit cell which are positioned such that a gold atom from each dimer lies at the vertices of a triangle that connects the three dimers. Of the three silver cluster compounds, one (n-Pr\sb4N)\sb2 (Ag\sb4\{2,4,6-(CH\sb3)\sb3C\sb6H\sb2CS\sb2 \}\sb6) $\cdot$1/2DMF$\cdot$H\sb2O, has a square-planar array of silver atoms, whereas the other two, (Ag\sb4\{2,4,6-(CH\sb3)\sb3C\sb6H\sb2CS\sb2\}\sb4(py)\sb3) $\cdot$1/2py and (Ag\sb4(o-CH\sb3C\sb6H\sb4CS\sb2)\sb4(py)\sb4), have distorted tetrahedral structures. The two trithioperoxybenzoate copper clusters, (Cu\sb4\{2,4,6-(CH\sb3)\sb3C\sb6H\sb2CS\sb2S\}\sb4) and Cu\sb4 (o-CH\sb3C\sb6H\sb4CS\sb2S)\sb4), exhibit distorted tetrahedral coordination. Triphenylphosphine was reacted with these clusters and resulted in seven monomeric derivatives with the formula (M(L)(PPh\sb3)\sb{\rm x}) where M = Au, L = o-CH\sb3C\sb6H\sb4CS\sb2, x = 1; M = Au, L = 2,4,6-(CH\sb3)\sb3C\sb6H\sb2CS\sb2, x = 1 or 2; M = Ag or Cu, L = o-CH\sb3C\sb6H\sb4CS\sb2 or 2,4,6-(CH\sb3)\sb3C\sb6H\sb2CS\sb2, x = 2. When x = 1, the gold compounds are linearly coordinated and the ligands are monodentate. When x = 2, the metals are all tetrahedrally coordinated and the ligands are bidentate. In addition to the above, seven other gold(I) complexes were synthesized using similar ligands, but solubility problems prevented single crystal growth and structural determinations. These ligands originated from tetraalkylammonium salts of the following substituted dithiobenzoates: p-methoxy-, p-fluoro-, p-phenyl-, p-benzoyl-, p-formyl-, p-acetyldithiobenzoate, and 1-dithionaphthoate. In order to further characterize some of these compounds, solid-state \sp{13}C CP-MAS NMR spectra were obtained for the o-methyl-, 2,4,6-trimethyl-, p-methoxy-, and p-fluorodithiobenzoatogold(I) complexes. All the gold(I) dithiobenzoate compounds were characterized by infrared and visible-ultraviolet spectroscopy. A discussion of the anomalous behavior of the p-phenyldithiobenzoate ligand in reactions with gold(III) and copper(II) is presented. No new light is shed on a continuing controversy regarding metal-metal bonding, its relative strength or even existence, in coinage metal clusters

Analysis of distortion data from TF30-P-3 mixed compression inlet test

A program was conducted to reduce and analyze inlet and engine data obtained during testing of a TF30-P-3 engine operating behind a mixed compression inlet. Previously developed distortion analysis techniques were applied to the data to assist in the development of a new distortion methodology. Instantaneous distortion techniques were refined as part of the distortion methodology development. A technique for estimating maximum levels of instantaneous distortion from steady state and average turbulence data was also developed as part of the program

A Synthesis of Research on Family Preservation and Family Reunification Programs

How effective are current efforts to preserve and reunify families in child welfare? In this paper we review research on programs aimed at preventing out-of-home placement of children, broader family preservation programs, and programs designed to reunify families with children in foster care.1 We examine what is known about the outcomes of these programs, relationships between service characteristics and outcomes, and the response of subgroups of clients to services. Claims that family preservation programs result in substantial reductions in the placement of children are based largely on non-experimental studies. Such studies do not provide solid evidence of program effects. Evidence from controlled studies of placement prevention effects is much weaker. The results of controlled studies suggest that difficulties in targeting services to families at risk of placement contribute to the lack of effects on likelihood of placement. The small amount of evidence on outcomes other than placement suggests that these programs have little effect on the recurrence of child maltreatment, although they may produce modest, short term improvements in some aspects of child and family functioning. Research on family reunification programs is in its infancy and there are very few controlled studies in this area. Available evidence is mixed. While some studies suggest that intensive, in-home services can speed the process of family reunification, the long-term effects of these programs are largely unknown. In particular, it is not clear whether intensive service programs increase the rates at which children return home, reduce the risk of foster care reentry, or lessen the chance of subsequent child maltreatment. We conclude our review with a discussion of directions for further research in this area

Mapping the speech code: Cortical responses linking the perception and production of vowels

The acoustic realization of speech is constrained by the physical mechanisms by which it is produced. Yet for speech perception, the degree to which listeners utilize experience derived from speech production has long been debated. In the present study, we examined how sensorimotor adaptation during production may affect perception, and how this relationship may be reflected in early vs. late electrophysiological responses. Participants first performed a baseline speech production task, followed by a vowel categorization task during which EEG responses were recorded. In a subsequent speech production task, half the participants received shifted auditory feedback, leading most to alter their articulations. This was followed by a second, post-training vowel categorization task. We compared changes in vowel production to both behavioral and electrophysiological changes in vowel perception. No differences in phonetic categorization were observed between groups receiving altered or unaltered feedback. However, exploratory analyses revealed correlations between vocal motor behavior and phonetic categorization. EEG analyses revealed correlations between vocal motor behavior and cortical responses in both early and late time windows. These results suggest that participants' recent production behavior influenced subsequent vowel perception. We suggest that the change in perception can be best characterized as a mapping of acoustics onto articulatio

Coronagraph particulate measurements. Skylab flight experiment T025

Major results of the Skylab T025 Coronagraph experiment designed to monitor the particulate contamination about the spacecraft and to study the earth's atmospheric aerosol distribution are presented. A model for comet outbursts based on the properties of amorphous ice and ground based narrow-band and white light photography of comet Kohoutek ten days to perihelion are included. The effect of atmospheric refraction on the analysis of the T025 atmospheric data was also investigated