Low-Energy Photodisintegration of the Deuteron and Big-Bang Nucleosynthesis

The photon analyzing power for the photodisintegration of the deuteron was measured for seven gamma-ray energies between 2.39 and 4.05 MeV using the linearly polarized gamma-ray beam of the High-Intensity Gamma-ray Source at the Duke Free-Electron Laser Laboratory. The data provide a stringent test of theoretical calculations for the inverse reaction, the neutron-proton radiative capture reaction at energies important for Big-Bang Nucleosynthesis. Our data are in excellent agreement with potential model and effective field theory calculations. Therefore, the uncertainty in the baryon density obtained from Big-Bang Nucleosynthesis can be reduced at least by 20%.Comment: 5 pages, 5 figure

Pulse generators with nanosecond leading edge duration based on TPI-type pseudospark switches for FEL complex

For FEL (Free Electron Laser) complex used in Duke University, pulse generators (kickers) of Injection, Extraction and Generator of injection into a big ring are developed and built. As fast switches TPI-type thyratrons (PSS - pseudospark switches) are employed. The thyratrons can be considered as an alternative to well-known switches, including hot cathode hydrogen thyratrons and up-to-date power solid state switches, whereas being more compact and cost-effective. Absence of hot cathode provides for turn-on time of the TPI about 3…5 ns in modes with thousands-amperes peak currents and sub-nanosecond jitter. The results of over 1.5 years of the pulse generators service are presented.Для комплексу ЛСЕ, створеного в університеті Duke, розроблено і виготовлено п’ять генераторів-"кікерів": генератор інжекції, генератор екстракції і генератор інжекції у велике кільце. Як швидкі комутатори використано тиратрони ТПІ-типу, які називаються також pseudospark swіtches - PSS. Відсутність розжарюваного катоду дозволяє ТПІ забезпечити в режимах з кілоамперними піковими струмами більші, ніж класичним тиратронам, терміни служби, зменшений час включення і субнаносекундний джиттер. Представлено результати експлуатації імпульсних генераторів на протязі більше 1,5 року.Для комплекса ЛСЭ, созданного в университете Duke, разработаны и изготовлены пять генераторов-«кикеров»: генератор инжекции, генератор экстракции и генератор инжекции в большое кольцо. В качестве быстрых коммутаторов использованы тиратроны ТПИ-типа, называемые также pseudospark switches - PSS. Отсутствие накаливаемого катода позволяет ТПИ обеспечить в режимах с килоамперными пиковыми токами большие, чем классическим тиратронам, сроки службы, уменьшенное время включения и субнаносекундный джиттер. Представлены результаты эксплуатации импульсных генераторов в течение более 1,5 лет

Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record

Fil: García, Rodolfo A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de Investigación en Paleobiología y Geología. General Roca. Río Negro; ArgentinaFil: Fernández, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. Río Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de Investigación en Paleobiología y Geología. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. Neuquén; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de Paleobiología y Geología. Universidad Nacional de Río Negro. Neuquén; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones Científicas y Transferencia Tecnológica. Anillaco. La Rioja; Argentin

Influence of light and heavy lanthanides on the physiological processes of taraxacum hybernum

© 2020, Editorial board of Journal of Experimental Biology and Agricultural Sciences. All rights reserved. The current study was carried out to study the influence of light and heavy lanthanides on the physiological process of Crimean-Sagyz/ Krim-saghyz (dandelion-Taraxacum hybernum). Lanthanide belongs to the group of light or heavy; infiltration of dandelion (Crimean saghyz) seeds with light and heavy lanthanides solutions increased the germination energy by 26%. The differences in the influence of light (cerium) and heavy (lutetium) were manifested in the quantum efficiency change of the photosystem 2 (PS II). Treatment of leaves with high concentrations (100 µM) led to a decrease of Y (II), moreover, under the influence of light lanthanide, the decrease was greater by 21%. It is assumed that the effect of the used lanthanides on the dandelion photosynthetic apparatus is multidirectional. Cerium influenced the PS II antenna complex, and lutetium influenced the reaction centers. A 10-fold decrease in the concentration did not change the nature of cerium action, except that Y (II) was restored already on the second day after treatment. The effect of lutetium became noticeable only by the 8th day after treatment when Y (II) became higher than that of untreated plants. Thus, the results of the study suggested that in dandelion leaves, lanthanides with a concentration of 10 µM increased the quantum efficiency of PS II in contrast to cerium