The effects of host resistance on the pick-up rates of ticks under natural infestation in Uganda

The pick-up rates of tick species by various resistant groups of animals, dipped once a month and not dipped were investigated under ranch conditions in Nabiswera, Luwero district, Uganda. During the first three weeks of exposure of cattle to natural tick infestation, two phases of tick build-up and one phase of decline in tick population were demonstrated with R. appendiculatus. The other tick species were too few for comparisons to be made. Each of these phases lasted about 7 days, except on animals dipped once a month where the phase of decline in tick population lasted only 3 days. These fluctuations in pick-up rates were attributed to differences between drop-off rhythms of engorged female ticks and reinfestation pressure of unfed ticks. The peak numbers of R. appendiculatus were determined by the carrying capacity of the ears of animals. After three weeks of exposure, the population of R. appendiculatus on cattle stabilized and this could be due to the attainment of an equilibrium balance between drop-off rhythms and reinfestations. The pick-up rates were highest on the low resistance (LR) groups of animals, followed by the medium resistance (MR) and was lowest on the high resistance groups (HR). These patterns of tick infestation were identical in both treatment groups of animals. The significance of using pick-up rates of ticks for differentiating the levels of host resistance in cattle are discussed

Towards development of a consistent orbit series for TOPEX, Jason-1, and Jason-2

International audienc

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit. © 2023. The Author(s). Published by IOP Publishing Ltd on behalf of the Astronomical Society of the Pacific (ASP). All rights reserved.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]