19,603 research outputs found
Self-synchronizing, bi-orthogonal coded PCM telemetry system
Communications and data handling system improves signal to noise ratio when transmission channel is perturbed by noise. Telemetry system consists of airborne source, Gaussian additive noise channel, and ground receiver unit. Advantages of system are given
Two new cichlid fishes, genus Cichlasoma, from Chiapas, Mexico
http://deepblue.lib.umich.edu/bitstream/2027.42/57129/1/OP693.pd
Possible Evidence of Gravity Wave Coupling into the Mid-latitude F Region Ionosphere During the SEEK Campaign
On five of eight observation nights during the 1996 SEEK (Sporadic E Experiment over Kyushu) campaign, Japan, unusual âwaveâlikeâ structures were imaged in the 630 nm thermospheric nightglow emission. Four of these events were observed to travel towards the southwest, providing new evidence in support of recent theories describing the coupling of mediumâscale gravity waves into the midâlatitude F region ionosphere. Available ionosonde data and the visual characteristics of the wave structures indicate no association with the occurrence of midâlatitude spread F or F region upwellings. Instead, the data support the novel concept of feedback from the ionosphere into the gravity wave, via the Perkins instability, to enhance its visibility
A comparison of the optical properties of radio-loud and radio-quiet quasars
We have made radio observations of 87 optically selected quasars at 5 GHz
with the VLA in order to measure the radio power for these objects and hence
determine how the fraction of radio-loud quasars varies with redshift and
optical luminosity. The sample has been selected from the recently completed
Edinburgh Quasar Survey and covers a redshift range of 0.3 < z < 1.5 and an
optical absolute magnitude range of -26.5 < M_{B} < -23.5 (h, q_{0} = 1/2). We
have also matched up other existing surveys with the FIRST and NVSS radio
catalogues and combined these data so that the optical luminosity-redshift
plane is now far better sampled than previously. We have fitted a model to the
probability of a quasar being radio-loud as a function of absolute magnitude
and redshift and from this model infer the radio-loud and radio-quiet optical
luminosity functions. The radio-loud optical luminosity function is featureless
and flatter than the radio-quiet one. It evolves at a marginally slower rate if
quasars evolve by density evolution, but the difference in the rate of
evolutions of the two different classes is much less than was previously
thought. We show, using Monte-Carlo simulations, that the observed difference
in the shape of the optical luminosity functions can be partly accounted for by
Doppler boosting of the optical continuum of the radio-loud quasars and explain
how this can be tested in the future.Comment: 33 pages, 9 postscript figures, uses the AAS aaspp4 LaTeX style file,
to appear in the 1 February 1999 issue of The Astrophysical Journa
Draft Genome Sequence of Lactobacillus jensenii Strain UMB7766, Isolated from the Female Bladder
Lactobacillus jensenii is a beneficial and prominent community member within both the vaginal and female urinary microbiota. As more genomes for L. jensenii strains are made publicly available, we gain more knowledge about this beneficial community member. Here, we present the draft genome sequence of L. jensenii UMB7766, which was isolated from a urine specimen from a catheterized female patient with recurrent urinary tract infections
Draft Genome Sequence of Streptococcus anginosus UMB7768, Isolated from a Woman with Recurrent UTI Symptoms
Streptococcus anginosus recently was implicated as a pathogen involved in urinary tract infections. A strain of S. anginosus was isolated from the female urogenital tract. Here, we present the draft genome sequence of S. anginosus strain UMB7768
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