1. |
- Oellers, D., et al.
(author)
-
Polarizing a stored proton beam by spin flip?
- 2009
-
In: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 674:4-5, s. 269-275
-
Journal article (peer-reviewed)abstract
- We discuss polarizing a proton beam in a storage ring, either by selective removal or by spin flip of the stored ions. Prompted by recent, conflicting calculations, we have carried out a measurement of the spin-flip cross section in low-energy electron–proton scattering. The experiment uses the cooling electron beam at COSY as an electron target. The measured cross sections are too small for making spin flip a viable tool in polarizing a stored beam. This invalidates a recent proposal to use co-moving polarized positrons to polarize a stored antiproton beam.
|
|
2. |
|
|
3. |
- Leoncini, Emanuele, et al.
(author)
-
Frequency of holoprosencephaly in the International Clearinghouse Birth Defects Surveillance Systems : Searching for population variations.
- 2008
-
In: Birth defects research. Clinical and molecular teratology. - : Wiley. - 1542-0752 .- 1542-0760. ; 82:8, s. 585-591
-
Journal article (peer-reviewed)abstract
- BACKGROUND: Holoprosencephaly (HPE) is a developmental field defect of the brain that results in incomplete separation of the cerebral hemispheres that includes less severe phenotypes, such as arhinencephaly and single median rnaxillary central incisor. Information on the epidemiology of HPE is limited, both because few population-based studies have been reported, and because small Studies must observe a greater number of years in order to accumulate sufficient numbers of births for a reliable estimate. METHODS: We collected data from 2000 through 2004 from 24 of the 46 Birth Defects Registry Members of the International Clearinghouse for Birth Defects Surveillance and Research. This Study is based on more than 7 million births in various areas from North and South America, Europe, and Australia. RESULTS: A total of 963 HPE cases were registered, yielding an overall prevalence of 1.31 per 10,000 births. Because the estimate was heterogeneous, possible causes of variations among populations were analyzed: random variation, Under-reporting and over-reporting bias, variation in proportion of termination of pregnancies among all registered cases and real differences among populations. CONCLUSIONS: The data do not suggest large differences in total prevalence of HPE among the studied Populations that would be useful to generate etiological hypotheses.
|
|
4. |
|
|