30,155 research outputs found
Measuring the Expansion of the Universe Through Changes in the CMB Photosphere
The expansion of the universe may be observed in ``realtime'' by measuring
changes in the patterns of the anisotropy in the CMB. As the universe ages, the
surface of decoupling--or the CMB photosphere--moves away from us and samples a
different gravitational landscape. The response of the CMB to this new
landscape results in a different pattern than we observe today. The largest
change occurs at l~900. We show that with an array of detectors that we may
envision having in a couple of decades, one can in principle measure the change
in the anisotropy with two high precision measurements separated by a century.Comment: 4 pages, 8 figures, submitted to Ap
Research in space science. Statistical evidence of the masses and evolution of galaxies
Average mass determinations of galaxies for problem of galactic evolutio
Apollo Soyuz pamphlet No. 7: Biology in zero-G
The effects of weightlessness on small living organisms, and methods for improving biological techniques were investigated in the seven experiments reported in this pamphlet which is intended as a curriculum supplement for secondary schools. Topics include: (1) killfish hatching and orientation; (2) microbial growth and changes in biorhythm; (3) cell separation by electrophoresis; (4) microbial exchange in the space raft; and (5) changes in astronaut immunity during spaceflight. The pamphlet is intended as a curriculum supplement for secondary schools
Apollo-Soyuz pamphlet no. 2: X-rays, gamma-rays
The nature of high energy radiation and its penetration through earth's atmosphere is examined with emphasis on X-rays, gamma rays, and cosmic radiation and the instruments used in their detection. The history of radio astronomy and the capabilities of the Uhuru satellite are summarized. The ASTP soft X-ray experiment (MA-048) designed to study the spectra in the range from 0.1 to 10 keV and survey the background over a large section of the sky is described, as well as the determination of SMC C-1 as an X-ray pulsar. The crystal activation experiment (MA-151) used to measure the radioactive isotopes created by cosmic rays in crystals used for gamma ray detectors is also discussed
Apollo-Soyuz pamphlet no. 6: Cosmic ray dosage
The radiation hazard inside spacecraft is discussed with emphasis on its effects on the crew, biological specimens, and spacecraft instruments. The problem of light flash sensations in the eyes of astronauts is addressed and experiment MA-106 is described. In this experiment, light flashes seen by blindfolded astronauts were counted and high energy cosmic ray intensity in the command module cabin were measured. The damage caused by cosmic ray hits on small living organisms was investigated in the Biostack 3 experiment (MA-107). Individual cosmic rays were tracked through layers of bacterial spores, small seeds, and eggs interleaved with layers of AgCl-crystal wafers, special plastic, and special photographic film that registered each cosmic ray particle passed
Predictions Based on the Clustering of Heterogeneous Functions via Shape and Subject-Specific Covariates
We consider a study of players employed by teams who are members of the
National Basketball Association where units of observation are functional
curves that are realizations of production measurements taken through the
course of one's career. The observed functional output displays large amounts
of between player heterogeneity in the sense that some individuals produce
curves that are fairly smooth while others are (much) more erratic. We argue
that this variability in curve shape is a feature that can be exploited to
guide decision making, learn about processes under study and improve
prediction. In this paper we develop a methodology that takes advantage of this
feature when clustering functional curves. Individual curves are flexibly
modeled using Bayesian penalized B-splines while a hierarchical structure
allows the clustering to be guided by the smoothness of individual curves. In a
sense, the hierarchical structure balances the desire to fit individual curves
well while still producing meaningful clusters that are used to guide
prediction. We seamlessly incorporate available covariate information to guide
the clustering of curves non-parametrically through the use of a product
partition model prior for a random partition of individuals. Clustering based
on curve smoothness and subject-specific covariate information is particularly
important in carrying out the two types of predictions that are of interest,
those that complete a partially observed curve from an active player, and those
that predict the entire career curve for a player yet to play in the National
Basketball Association.Comment: Published at http://dx.doi.org/10.1214/14-BA919 in the Bayesian
Analysis (http://projecteuclid.org/euclid.ba) by the International Society of
Bayesian Analysis (http://bayesian.org/
Apollo-Soyuz pamphlet no. 1: The flight
The goals of the Apollo-Soyuz Test Project are described in this first in a series of nine pamphlets designed as a curriculum supplement for teachers, supervisors, curriculum specialists, and textbook writers as well as for the general public. Aspects of the space flight covered include descriptions of the astronaut-cosmonaut meeting and of the spacecraft and landing module; spacecraft launch; control, and rendezvous; crew work schedule; and telemetry. Experiments performed are listed in tables, and their major results are summarized
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