National Geodetic Satellite Program, Part II: Evaluation

The National Geodetic Satellite Program (NGSP) was evaluated to see if the program objectives were actually met. An inspection of the results shows that the general objectives were met. It is concluded that the specific results of the NGSP were too generally stated to allow one to tell whether they were met or were unobtainable. Analysis of methods and results shows that the standard deviations assigned to the results are indications of precision, not accuracy, and cannot be used to rank the various sets of coordinates in order of accuracy

Diffuse Non-thermal X-ray Emission: Evidence for Cosmic-ray Acceleration at the Shock Front in IC1262

We report the first localization of diffuse, non-thermal, X-ray emission from a nearby galaxy cluster. Using Chandra data, we have isolated a diffuse non-thermal X-ray component with a photon index, Gamma_ X = 2.21 +0.14 -0.15 and a flux of 9.5 +1.1 -2.5 x 10^-5 photons cm^-2 s^-1 keV^-1 at 1 keV, that extends from ~1'.5 to ~2'.5 to the south of the X-ray flux peak. Comparison to simulations implies that the diffuse non-thermal emission is produced by primary electrons, accelerated at shocks to relativistic velocities. Using these results and the flux and hardness maps produced with data from the Chandra Advanced CCD Imaging Spectrometer, we conclude that a smaller subclump coming from the north merged with IC1262. The offset of the cD galaxy from the X-ray peak and large peculiar velocity indicate that the subclump's impact parameter was to the west and on the near side of IC1262.Comment: 5 pages, 4 figures, 2 tables. Accepted by ApJ

Wavelet Analysis of Inhomogeneous Data with Application to the Cosmic Velocity Field

In this article we give an account of a method of smoothing spatial inhomogeneous data sets by using wavelet reconstruction on a regular grid in an auxilliary space onto which the original data is mapped. In a previous paper by the present authors, we devised a method for inferring the velocity potential from the radial component of the cosmic velocity field assuming an ideal sampling. Unfortunately the sparseness of the real data as well as errors of measurement require us to first smooth the velocity field as observed on a 3-dimensional support (i.e. the galaxy positions) inhomogeneously distributed throughout the sampled volume. The wavelet formalism permits us to introduce a minimal smoothing procedure that is characterized by the variation in size of the smothing window function. Moreover the output smoothed radial velocity field can be shown to correspond to a well defined theoretical quantity as long as the spatial sampling support satisfies certain criteria. We argue also that one should be very cautious when comparing the velocity potential derived from such a smoothed radial component of the velocity field with related quantities derived from other studies (e.g : of the density field).Comment: 19 pages, Latex file, figures are avaible under requests, published in Inverse Problems, 11 (1995) 76

Cluster mergers, core oscillations, and cold fronts

We use numerical simulations with hydrodynamics to demonstrate that a class of cold fronts in galaxy clusters can be attributed to oscillations of the dark matter distribution. The oscillations are initiated by the off-axis passage of a low-mass substructure. From the simulations, we derive three observable morphological features indicative of oscillations: 1) The existence of compressed isophotes; 2) The regions of compression must be alternate (opposite and staggered) and lie on an axis passing through the center of the cluster; 3) The gradient of each compression region must pass through the center of the cluster. Four of six clusters reported in the literature to have cold fronts have morphologies consistent with the presence of oscillations. The clusters with oscillations are A496, A1795, A2142, and RX J1720.1+2638. Galaxy clusters A2256 and A3667 are not consistent so the cold fronts are interpreted as group remnants. The oscillations may be able to provide sufficient energy to solve the cooling-flow problem and, importantly, provide it over an extended duration.Comment: Submitted to ApJ. 11 pages, 9 figure

Effects of Science Vocabulary Exposure Prior to Instruction: Interdisciplinary Instruction in Science and Language

This study investigated the use of a prereading strategy that gave 6th grade students exposure to technical science vocabulary before science instruction. The prior exposure consisted of listening/speaking and graphophonemic manipulation of the science terms. The science instruction promoted student inquiry and problem solving in each of the three phases of the science unit on rocketry. These phases were model construction, informational material and hands-on experiments. A treatment-control group comparison was conducted. After each of the phases a posttest was given to both groups. Data were collected and compared for three posttests. The technical vocabulary awareness treatment group demonstrated no significant advantage in their science concept learning as a result of having receiving the prior vocabulary exposure. It was noteworthy that a majority of the students in both groups received average to superior + posttest scores indicating a good mastery of the science concepts

Response of rat hindlimb muscles to 12 hours recovery from tail-cast suspension

Previous work has shown a number of biochemical changes which accompany atrophy or reduced muscle growth in hindlimb of tail-casted, suspended rats. These results clearly show that altered muscle growth was due to changes in protein turnover. Accordingly, the rise in soleus tyrosine following unloading reflects the more negative protein balance. Other major changes we found included slower synthesis of glutamine as indicated by lower ratios of glutamine/glutamate and reduced levels of aspartate which coincide with slower aspartate and ammonia metabolism in vitro. In conjunction with the study of SL-3 rats, which were subjected to 12 h of post-flight gravity, a study of the effects of 12 h eight bearing on metabolism of 6-day unloaded hindlimb muscles was carried out

Responses of skeletal muscle to unloading, a review

Suspension models were used to study muscle response to reduced activity. During 6 days of tail casting, the soleus (SOL) atrophies while the extensor digitorum longus grows relatively normally. After discounting those changes in both muscles due primarily to increased secretion of adrenal hormones, the following conclusions regarding the specific responses of the SOL could be drawn: (1) Atrophy is probably due primarily to increased protein degradation; (2) Decreased synthesis of glutamine may result from reduced availability of ammonia due to diminished use of ATP; (3) Greater muscle glycogen seems to reflect an increased response to insulin of glucose uptake which leads to greater glucose metabolism; and (4) Faster catabolism of branched-chain amino acids can be attributed to enhanced flux through ketoacid dehydrogenase. Studies by others using tail casted suspended rats showed in the SOL: (1) a gradual switch from type 1 to type 2 fibers; (2) increased acid protease activity; and (3) altered muscle function and contractile duration. Using harness suspended rats, others showed in the SOL: (1) significant atrophy; (2) increased numbers of glucocorticoid receptors; and (3) no change in muscle fatigability