منابع مشابه
5.5 N&V 029 am
when applied to cichlid fishes it reliably causes spectacular evolutionary radiations of hundreds of new species. Generalist riverine cichlids have given rise to flocks of highly specialized fishes in each of the major lakes in East Africa. Now, on page 90 of this issue, Joyce and colleagues describe a previously unrecognized radiation of cichlids in the extinct Lake Makgadikgadi, whose descend...
متن کامل5.8 N&v 619 Am
When driving a car, steering is crucial for getting where you want to go. Imagine driving a car with no steering-wheel in Manhattan: you could go to some places, along north–south avenues or east–west streets, but you would be very limited in your choice of destination. Laser scientists faced a similar limitation when trying to drive quantum systems, such as atoms or molecules, into desired sta...
متن کاملar X iv : h ep - p h / 99 07 42 5 v 2 6 A ug 1 99
At a future Linear Collider one will be able to determine the masses of charginos and neutralinos and their pair production cross sections to high accuracies. We show how systematically including the cross sections into the analysis improves the measurement of the underlying mass parameters, including potential CP violating phases. In addition, we investigate how experimental errors will affect...
متن کاملar X iv : h ep - p h / 98 09 42 3 v 1 1 7 Se p 19 98 UCSD
Theoretical predictions for inclusive semileptonic B decay rates are rewritten in terms of the Υ(1S) meson mass instead of the b quark mass, using a modified perturbation expansion. This method gives theoretically consistent and phenomenologically useful results. Perturbation theory is well behaved, and the largest theoretical error in the predictions coming from the uncertainty in the quark ma...
متن کاملAtomic Oxygen in the Comae of Comets
We report on the detection of atomic oxygen lines in the spectra of 8 comets. These forbidden lines are a result of the photodissociation of the parent oxygen-bearing species directly into an excited state. We used high resolution spectra obtained at the McDonald Observatory 2.7m telescope to resolve the cometary oxygen lines from the telluric oxygen lines and from other cometary emissions. We ...
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ژورنال
عنوان ژورنال: Astronomische Nachrichten
سال: 1921
ISSN: 0004-6337,1521-3994
DOI: 10.1002/asna.19212141605