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159 results on '"Davis, L R"'

1. Chromosome-level genome assembly for the Aldabra giant tortoise enables insights into the genetic health of a threatened population

Author

Çilingir, F G; https://orcid.org/0000-0002-4575-1487, A’Bear, L, Hansen, D, Davis, L R, Bunbury, N, Ozgul, A, Croll, D; https://orcid.org/0000-0002-2072-380X, Grossen, Christine; https://orcid.org/0000-0003-4157-1910, Çilingir, F G; https://orcid.org/0000-0002-4575-1487, A’Bear, L, Hansen, D, Davis, L R, Bunbury, N, Ozgul, A, Croll, D; https://orcid.org/0000-0002-2072-380X, and Grossen, Christine; https://orcid.org/0000-0003-4157-1910

Abstract

The Aldabra giant tortoise (Aldabrachelys gigantea) is one of only two giant tortoise species left in the world. The species is endemic to Aldabra Atoll in Seychelles and is considered vulnerable due to its limited distribution and threats posed by climate change. Genomic resources for A. gigantea are lacking, hampering conservation efforts focused on both wild and ex-situ populations. A high-quality genome would also open avenues to investigate the genetic basis of the exceptionally long lifespan. Here, we produced the first chromosome-level de novo genome assembly of A. gigantea using PacBio High-Fidelity sequencing and high-throughput chromosome conformation capture (Hi-C). We produced a 2.37 Gbp assembly with a scaffold N50 of 148.6 Mbp and a resolution into 26 chromosomes. RNAseq-assisted gene model prediction identified 23,953 protein-coding genes and 1.1 Gbp of repetitive sequences. Synteny analyses among turtle genomes revealed high levels of chromosomal collinearity even among distantly related taxa. We also performed a low-coverage re-sequencing of 30 individuals from wild populations and two zoo individuals. Our genome-wide population structure analyses detected genetic population structure in the wild and identified the most likely origin of the zoo-housed individuals. The high-quality chromosome-level reference genome for A. gigantea is one of the most complete turtle genomes available. It is a powerful tool to assess the population structure in the wild population and reveal the geographic origins of ex-situ individuals relevant for genetic diversity management and rewilding efforts.

Published
2022

19. Supplement to the 1975 report on active and planned spacecraft and experiments

Author

Horowitz, R and Davis, L. R

Subjects
Astrodynamics
Abstract

A listing and brief description of spacecraft and experiments designed to update the January 1975 report on active and planned spacecraft and experiments to March 31, 1975 was presented. The information is given in two sections. In the first, spacecraft and experiments that have become known to NSSDC since the original report or that have changed significantly are described. In the second, an alphabetical listing is given for all spacecraft and experiments described in the first section and in the original report. It also updates status of operation and launch dates to March 31, 1975.

Published
1975

20. The 1975 report on active and planned spacecraft and experiments

Author

Horowitz, R and Davis, L. R

Subjects
Astronautics (General)
Abstract

Information is presented on current and planned spacecraft activity for various disciplines: astronomy, earth sciences, meteorology, planetary sciences, aeronomy, solar physics, and life sciences. For active orbiting spacecraft, the epoch date, orbit type, orbit period, apoasis, periapsis, and inclination are given along with the spacecraft weight, launch date, launch site, launch vehicle, and sponsoring agency. For each planned orbiting spacecraft, the orbit parameters, planned launch date, launch site, launch vehicle, spacecraft weight, and sponsoring agency are given.

Published
1975

21. Supplement no. 1 to the January 1974 report on active and planned spacecraft and experiments

Author

Horowitz, R and Davis, L. R

Subjects
Space Sciences
Abstract

Updated information and descriptions on spacecraft and experiments are listed according to spacecraft name and principle experimental investigator. A cumulative index of active and planned spacecraft and experiments is provided; bar graph indexes for electromagnetic radiation experiments are included in table form.

Published
1974

31. Outer zone protons.

Author

Davis, L. R and Williamson, J. M

Subjects
Space Radiation
Abstract

Intensity and spectra of 100 to 1700 kev protons in region above two earth radii measured by charged particle detectors on Explorer XII, XIV AND XV

Published
1966

32. Low energy trapped protons and electrons.

Author

Davis, L. R

Subjects
Space Radiation
Abstract

Explorer satellite XII, XIV and XV MEASUREMENTS, noting directional intensity energy flux, spatial distribution and spectra of low energy trapped protons and electrons

Published
1965

33. LOW-ENERGY TRAPPED PROTONS

Author

Davis, L. R and Williamson, J. M

Subjects
Mathematics
Abstract

Low energy protons and electrons in geomagnetically trapped radiation

Published
1963

36. Heat Transfer and Fluid Mechanics Institute, 24th, Oregon State University, Corvallis, Ore., June 12-14, 1974, Proceedings

Author

Davis, L. R and Wilson, R. E

Subjects
Thermodynamics And Combustion
Abstract

Recent theoretical and experimental studies in heat transfer and fluid mechanics, including some environmental protection investigations, are presented in a number of papers. Some of the topics covered include condensation heat transfer, a model of turbulent momentum and heat transfer at points of separation and reattachment, an explicit scheme for calculations of confined turbulent flows with heat transfer, heat transfer effects on a delta wing in subsonic flow, fluid mechanics of ocean outfalls, thermal plumes from industrial cooling water, a photochemical air pollution model for the Los Angeles air basin, and a turbulence model of diurnal variations in the planetary boundary layer. Individual items are announced in this issue.

Published
1974

40. Defective yeast opsonisation and functional deficiency of complement in sickle cell disease.

Author

LARCHER, V. F., WYKE, R. J., DAVIS, L. R., STROUD, C. E., WILLIAMS, ROGER, and Williams, R

Abstract

Opsonisation of heat-killed baker's yeast, functional activity of the total alternative pathway of complement, and factor B detected functionally and immunochemically were significantly reduced in 72 children with sickle cell disease compared with 40 age-matched black control children. There was significant correlation between functional activity of the total alternative pathway and functionally measured factor B, but not between factor B measured functionally and immunochemically. The opsonisation defect could be corrected in vitro by normal serum, and factor B-depleted serum, and was qualitatively similar to that seen in patients with primary yeast opsonisation deficiency. Serial studies showed that these serum defects were persistent. Reduction in the activity of components of the alternative pathway of complement and opsonisation was found in 4 patients who had recovered from pneumococcal meningitis and in one who developed osteomyelitis. Defects of yeast opsonisation and complement which are common in patients with sickle cell disease, may partly explain the children's increased susceptibility to infection, and might help to identify individuals especially at risk. [ABSTRACT FROM AUTHOR]

Published
1982

41. Failure of laboratory and radiological studies to predict jejunal mucosal atrophy.

Author

SANDERSON, MARY C., DAVIS, L. R., MOWAT, ALEX P., Sanderson, M C, and Mowat, A P

Abstract

Of 58 children with suspected malabsorption, 27 were shown to have subtotal or partial atrophy, and 31 had normal mucosal histology. Oral glucose tolerance tests, faecal fat excretion, D-xylose excretion tests, Prosparol absorption studies, haematological investigations, and radiological examination of the small bowel failed to distinguish these two groups and frequently gave misleading results. It is concluded that in suspected coeliac disease small intestinal biopsy should be performed as a primary investigation. [ABSTRACT FROM AUTHOR]

Published
1975

42. Occurrence of infection with a parvovirus-like agent in children with sickle cell anaemia during a two-year period.

Author

Anderson, M J, Davis, L R, Hodgson, J, Jones, S E, Murtaza, L, Pattison, J R, Stroud, C E, and White, J M

Abstract

The occurrence of infection with a parvovirus-like agent during the period April 1979-May 1981 in children attending a single sickle cell clinic in London was investigated. Virus was detected in serum by counter-current immunoelectrophoresis (CIE) and immunoelectron microscopy (IEM). Viral antibody was detected by CIE and specific IgM antibody by an IgM-antibody capture assay. Of the 68 children studied nine presented in aplastic crisis and evidence of infection with the parvovirus-like agent at the time of the crisis was found in all nine. Eighteen of the other children were antibody-positive at some time during the study. In 11 children there was no evidence of recent infection; however, two of these had a history of aplastic crisis in previous years. The other seven seroconverted during the course of the study but did not show any haematological effects. Five of these had a primary infection, one appeared to have reinfection and in the seventh there were insufficient data to distinguish between the two. Possible explanations for the difference between those presenting with aplastic crisis and those with asymptomatic seroconversion are discussed. [ABSTRACT FROM PUBLISHER]

Published
1982

43. Changing blood picture in sickle-cell anaemia from shortly after birth to adolescence.

Author

Davis, L R

Abstract

The blood picture of children with sickle-cell anaemia was found to change with age. The changes were most marked in the first year but the mean level of haemoglobin, haemoglobin F, and target cells fell until adolescence, and irreversibly sickled cells rose. Reticulocytes, Howell Jolly bodies, and normablasts altered little after one year. The fall in haemoglobin F suggested a delayed changeover from fetal to adult haemoglobin production. It was concluded that the blood changes in sickle-cell anaemia were progressive throughout childhood. [ABSTRACT FROM PUBLISHER]

Published
1976

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