New Results for Double-Beta Decay of Mo-100 to Excited Final States of Ru-100 Using the TUNL-ITEP Apparatus

The coincidence detection efficiency of the TUNL--ITEP apparatus designed for measuring half-life times of two-neutrino double-beta decay transitions to excited final states in daughter nuclei has been measured with a factor of 2.4 improved accuracy. In addition, the previous measuring time of 455 days for the study of the Mo-100 two-neutrino double-beta decay to the first excited 0+ state in Ru-100 has been increased by 450 days, and a new result (combined with the previous measurement obtained with the same apparatus) for this transition is presented: T_(1/2) = [5.5 (+1.2/-0.8) (stat) +/- 0.3 (syst)] x 10^20 y. Measured two-neutrino double-beta decay half-life times to excited states can be used to test the reliability of nuclear matrix element calculations needed for determining the effective neutrino mass from zero-neutrino double-beta decay data. We also present new limits for transitions to higher excited states in Ru-100 which, if improved, may be of interest for more exotic conjectures, like a bosonic component to neutrino statistics

Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths

We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributions (SEDs) and global spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering array of morphologies, with jets, trails, and other structures. Several of the 23 so far identified magnetars show evidence for continuous or sporadic emission of material, sometimes associated with giant flares, and a few possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release

Tropical Asian mega-delta ponds:Important and threatened socio-ecological systems

This paper uses multimedia to showcase the narratives and lived experiences of those who live and work in tropical Asian mega-deltas, and as such is the first journal article of its kind in the field of Regional Geography. Using videos, photography and audio this paper describes the characteristics of ponds and their place in the intrinsically connected human-environmental fabric of these delta regions. The aim is to bring to life descriptive inventories and provide greater weight in support of our conclusion that tropical Asian mega-delta ponds are important and threatened systems. River deltas comprise just 1% of land cover worldwide but support the livelihoods of more than 500 million people. Delta research has historically focused on the major river channels and the socio-ecological role of ponds has been overlooked despite their large number and surface area. Ponds are intrinsically linked to daily life (potable water, sanitation, bathing, washing), industry (aquaculture, agriculture) and the natural-cultural heritage (religion, folklore) of deltas. In contrast to the larger river channels, ponds are likely to be significant stores and processors of nutrients, including carbon, and pollutants at annual to decadal scales, on account of their heavy anthropogenic use and smaller individual sizes. Consequently, they are severely polluted water sources and pose significant public health risks. In this review, we use case studies from three Asian mega-deltas (the Red River Delta and the Mekong River Delta, Vietnam, and the Ganges-Brahmaputra-Meghna Delta, India and Bangladesh) to highlight the importance of Asian mega-delta ponds as important socio-ecological systems in their own right. We discuss future environmental challenges, knowledge gaps on the ecological function and biodiversity of these habitats, management and policy practices, and the capacity of ponds to achieve the UN Sustainable Development Goals. The information, practices and views in this article are those of the author(s) and do not necessarily reflect the opinion of the Royal Geographical Society (with IBG)

A Novel Form of Ataxia Oculomotor Apraxia Characterized by Oxidative Stress and Aapoptosis Resistance

Several different autosomal recessive genetic disorders characterized by ataxia with oculomotor apraxia (AOA) have been identified with the unifying feature of defective DNA damage recognition and/or repair. We describe here the characterization of a novel form of AOA showing increased sensitivity to agents that cause single-strand breaks (SSBs) in DNA but having no gross defect in the repair of these breaks. Evidence for the presence of residual SSBs in DNA was provided by dramatically increased levels of poly (ADP-ribose)polymerase (PARP-1) auto-poly (ADP-ribosyl)ation, the detection of increased levels of reactive oxygen/nitrogen species (ROS/RNS) and oxidative damage to DNA in the patient cells. There was also evidence for oxidative damage to proteins and lipids. Although these cells were hypersensitive to DNA damaging agents, the mode of death was not by apoptosis. These cells were also resistant to TRAIL-induced death. Consistent with these observations, failure to observe a decrease in mitochondrial membrane potential, reduced cytochrome c release and defective apoptosis-inducing factor translocation to the nucleus was observed. Apoptosis resistance and PARP-1 hyperactivation were overcome by incubating the patient\u27s cells with antioxidants. These results provide evidence for a novel form of AOA characterized by sensitivity to DNA damaging agents, oxidative stress, PARP-1 hyperactivation but resistance to apoptosis

Regulation and incentives in telecommunications

Period of award 1 Apr 1994 - 30 Jun 1996SIGLEAvailable from British Library Document Supply Centre-DSC:3739.0604(L11425102601) / BLDSC - British Library Document Supply CentreGBUnited Kingdo