Readers ask about cat contraception, big G and more
Feline fecundity
One shot of an experimental gene remedy saved feminine cats kitten-free for a minimum of two years, Erin Garcia de Jesús reported in “Gene remedy prevents cat being pregnant” (SN: 7/15/23 & 7/29/23, p. 10).
Reader Christie Borem requested why the researchers centered on feminine cats.
It solely takes one “pesky” male cat to impregnate a number of females, says reproductive biologist David Pépin of Massachusetts Common Hospital and Harvard Medical Faculty. If male contraceptives alone have been used, practically each male cat would want to obtain remedy to forestall pregnancies in females. However every feminine cat that receives contraception is one much less feminine giving start to litters, whatever the male inhabitants, Pépin says. What’s extra, surgical sterilization is a extra invasive process for feminine cats than it’s for males, which makes females an excellent goal for fast and simple contraception, he says.
With that mentioned, contraception for each female and male cats could be useful for controlling populations of feral cats, Pépin says. Researchers are creating new contraception strategies for male cats, however none have proved everlasting.
Spinning out
The North Pole drifted about 1.6 meters towards the east coast of Greenland between 1993 and 2010. About 78 centimeters, or about 4.4 cm per yr, of that shift was attributable to irrigation alone, Sid Perkins reported in “Irrigation nudges the North Pole” (SN: 7/15/23 & 7/29/23, p. 12).
Reader Hugh Black questioned if components akin to inhabitants progress and local weather change additionally contribute to polar drift.
Any comparatively everlasting redistribution of mass would contribute to float, however water most likely has the most important affect, says Clark Wilson, a geophysicist on the College of Texas at Austin.
Glacier and ice sheet melting, which has accelerated over the past a number of a long time, contributed about 4.1 cm/yr to the North Pole’s drift through the examine interval, Wilson and colleagues estimated. The group hasn’t seemed on the impact of inhabitants progress, however Wilson speculates that its contribution to polar drift would doubtless be smaller than that of water impounded in reservoirs behind dams, which the group estimated to be about 1.5 cm/yr through the examine interval.
What’s the massive G?
Physicists have spent centuries making an attempt to pin down the worth of Newton’s gravitational fixed, or “massive G,” James R. Riordon reported in “What’s massive G?” (SN: 7/15/23 & 7/29/23, p. 28).
Labs around the globe trying to measure G, which displays the energy of gravity between issues with mass, have turned up values that disagree. Reader Richard Bisk questioned whether or not darkish matter could possibly be influencing the measurements.
“Scientists have been making an attempt to detect darkish matter on Earth for many years with out a lot success. We’re nonetheless at midnight,” says physicist Stephan Schlamminger of the Nationwide Institute of Requirements and Know-how in Gaithersburg, Md. Some efforts to detect darkish matter have used torsion balances, a instrument that experimentalists measuring G additionally use. Since darkish matter has but to be detected with these efforts, it’s comparatively protected to imagine that the mysterious stuff doesn’t affect measurements of G in a major means, Schlamminger says. Nonetheless, dismissing the concept utterly “could be silly as a result of detecting darkish matter with a G experiment might simply result in a [Nobel Prize],” he says.
