The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation.

Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

[Diagnostic evaluation of the soft tissue profile]. / Valutazioni diagnostiche sul profilo cutaneo.

The Authors report a cephalometric analysis of soft tissues profile to help the orthodontist to do a correct treatment plane referred to the three thirds of the face and not limited to the lower one only. This analysis is related to adult patients, and because the well known considerations about development of the soft tissues, it should be a predictable analysis of soft tissues profile at the end of growth.

[Extrusive therapy and periodontal alignment. Considerations and indications. 2]. / Terapia estrusiva ed allineamento parodontale. Considerazioni ed indicazioni - Nota II.

The Authors report some clinical cases treated with orthodontic forced eruption, periodontal surgery and prosthetic rehabilitation. The theoretic first part of this work was published on Dental Cadmos no. 9/87.

[Oral respiration. Diagnosis and physiopathology]. / Respirazione di tipo orale. Clinica e fisiopatologia.

The oral breathing can change the functional connections during the development of the facial bones of the children. All this causes an abnormal growth of the facial bones and of the dental structures. This work developed a new discipline to remove this problem.

[Magnets and orthodontics. Biological-clinical study. 2]. / Magneti e ortognatodonzia: indagine biologico-clinica. Nota II.

The authors after preliminary remarks on new magnetic alloys, stress some biomechanic aspects related to distalization of upper molars. Radiologic examination of teeth during distalization shows a good rate of crown/tooth ratio movement. Where magnets were worn in combination with extraoral traction, they seemed to be more effective on the "test" sides rather than on the "control" sides where only extraoral forces acted.

[Magnets and orthognathodontics. Biological-clinical overview. 1]. / Magneti e ortognatodonzia. Indagine biologico-clinica. Nota I.

A review of the physical properties of the magnetic fields is reported. Particular attention has been paid to the biological and clinical aspects of the electromagnetic fields applied to living structures of cells and bone tissue both susceptible to this exposition.