RESUMEN
Enamel macro- and microstructure has been studied in the teeth of Merck's rhinoceros (Stephanorhinus kirchbergensis Jäger, 1839), woolly rhinoceros (Coelodonta antiquitatis Blumenbach, 1799), and rhinoceroses from the Tetyukhinskaya (44°35' N, 135°36' E) and Sukhaya (43°09' N, 131°28' E) caves in southern Primorye. The teeth from the caves were identified as the teeth of Merck's rhinoceros. Radiocarbon dating and accompanying animal species enabled the dating of Merck's rhinoceros remains to the Late Pleistocene (marine isotope stages 5-2). These finds mark the extreme eastern boundary of the Merck's rhinoceros species range in the Late Pleistocene. The living range reached the Pacific Ocean coast during a certain time interval within this epoch. This was due to the abundance of tree and shrub vegetation in the area during the Late Pleistocene.
Asunto(s)
Fósiles , Perisodáctilos , Diente , Animales , Cuevas , Esmalte Dental/anatomía & histología , Esmalte Dental/ultraestructura , Datación Radiométrica , SiberiaRESUMEN
An M1 tooth of Asian black bear (Ursus (Euarctos) thibetanus G. Cuvier, 1823) was found in deposits of the Tetyukhinskaya cave (Middle Sikhote-Alin, 44°35'N, 135°36'E). This finding is the first reliable evidence of Asian black bear's presence in Pleistocene of Primorye. Its morphological and morphometric descriptions are given. The period of inhabitation of U. (E.) thibetanus determined based on the radiocarbon date obtained during the study of the tooth, is 39 874 ± 133 BP (NSK-850, UGAMS-21786), which corresponds to the middle of Marine Isotope Stage 3 (MIS 3) of Late Pleistocene. The composition of ancient theriofauna indicates the existence of wide variety of landscapes in Primorye in the middle of Late Pleistocene. A refugium of forest fauna, in which species of taiga, nemoral, and Central Asian mountain-forest theriocomplexes were present, was located in southern Primorye in Late Pleistocene.
Asunto(s)
Diente/anatomía & histología , Ursidae/anatomía & histología , Ursidae/clasificación , Animales , Asia , Europa (Continente) , Extinción Biológica , Historia Antigua , Datación Radiométrica , Especificidad de la EspecieRESUMEN
A 1000 keV, 5 MW, 1000 s neutral beam injector based on negative ions is being developed in the Budker Institute of Nuclear Physics, Novosibirsk in collaboration with Tri Alpha Energy, Inc. The innovative design of the injector features the spatially separated ion source and an electrostatic accelerator. Plasma or photon neutralizer and energy recuperation of the remaining ion species is employed in the injector to provide an overall energy efficiency of the system as high as 80%. A test stand for the beam acceleration is now under construction. A prototype of the negative ion beam source has been fabricated and installed at the test stand. The prototype ion source is designed to produce 120 keV, 1.5 A beam.
RESUMEN
At the BINP, a pilot accelerator based epithermal neutron source is now in use. Most recent investigations on the facility are related with studying the dark current, X-ray radiation measuring, optimization of H(-)-beam injection and new gas stripping target calibrating. The results of these studies, ways of providing stability to the accelerator are presented and discussed, as well as the ways of creating the therapeutic beam and strategies of applying the facility for clinical use.
Asunto(s)
Terapia por Captura de Neutrón de Boro/instrumentación , Terapia por Captura de Neutrón de Boro/tendencias , Predicción , Aceleradores de Partículas/instrumentación , Radiometría/instrumentación , Radiometría/tendencias , Diseño de Equipo , Análisis de Falla de Equipo , Dosificación Radioterapéutica , Federación de RusiaRESUMEN
Description of a new cestode species Vampirolepis insula sp. n. parasitizing Ambliotus nilssonni (Keyserling et Blasius, 1839 and Plecotus auritus Linnaeus, 1758 from the islands Sakhalin and Kunashir is given. The new species is closely related to the species group within the genus Vampirolepis having 30 rostellar hooks 0.020-0.022 mm length with the blades shorter than guard. The group includes V. balsaci (Joyeux et Baer, 1934) Spassky, 1954, Sawada, 1974 and V. ozensis Sawada, 1974. The main differential character of the new species is the position of genital pores on the left side of proglottides. Moreover, the new species differs from V. balsaci and V. ozensis by almost twice larger size ofscolex, suckers, and rostellum. Vampirolepis insula sp. n. also differs from V. ogaensis and V ozensis by a larger size of ovary and vitelline gland.
Asunto(s)
Cestodos/clasificación , Quirópteros/parasitología , Animales , Cestodos/anatomía & histología , Cestodos/aislamiento & purificación , Femenino , Intestino Delgado/parasitología , Masculino , SiberiaRESUMEN
Neutral beam with geometrical focusing for plasma heating in moderate-size plasma devices has been developed in Budker Institute of Nuclear Physics, Novosibirsk. When operated with hydrogen, the neutral beam power is 1 MW, pulse duration is 1 s, beam energy is 40 keV, and angular divergence is 1.2 degrees. Initial ion beam is extracted and accelerated by triode multiapertures ion-optical system. To produce 1 MW neutral beam, about 40 A proton current is extracted with nominal current density of 320 mA/cm(2). Ion-optical system has 200 mm diameter grids with 44% transparency. The grids have inertia cooling and heat is removed between the pulses by water flowing in channels placed on periphery of the grids. A plasma emitter for ion extraction is produced by rf-plasma box. Ion species mix of rf plasma source amounts to 70%, 20%, and 10% of H(+), H(2)(+), and H(3)(+) ions, respectively, by current. Heavy impurities contribute less than 0.3%.
RESUMEN
A well-known Pierce solution that allows focusing a beam of charged particles using properly shaped electrodes outside the beam aperture is generalized to the case of an accelerating system with inhomogeneous emission current density. It is shown that the defocusing effect of the space charge can, in principle, be evenly compensated over the entire cross section of the beam. In contrast to the beam with a uniform emission current density, both the electric potential and the transverse electric field must be controlled along the beam boundary in order to eliminate the angular divergence. However, eliminating the angular spread evenly across the beam constitutes a mathematically ill-posed problem which needs to be solved with the use of one or another method of regularization. An alternative way of diminishing beam emittance is proposed for the beam where the emission current is uniform across the entire aperture except for a narrow beam edge layer and a simple formula for the Pierce electrodes is derived. Numerical simulation has proved the reasonable accuracy of our analytical theory.
RESUMEN
A 2 MeV proton tandem accelerator with vacuum insulation was developed and first experiments are carried out in the Budker Institute of Nuclear Physics (Novosibirsk). The accelerator is designed for neutron production via reaction (7)Li(p,n)(7)Be for the boron neutron-capture therapy of the brain tumors, and for explosive detection based on 9.1724 MeV resonance gamma, which are produced via reaction (13)C(p,gamma)(14)N, absorption in nitrogen.