Gamma-spectrometric uranium age-dating using intrinsic efficiency calibration

A non-destructive, gamma-spectrometric method for uranium age-dating is presented which is applicable to material of any physical form and geometrical shape. It relies on measuring the daughter/parent activity ratio 214Bi/234U by low-background, high-resolution gamma-spectrometry using intrinsic efficiency calibration. The method does not require the use of any reference materials nor the use of an efficiency calibrated geometry.Comment: 10 pages, 3 figures, accepted for publication in Nucl. Instrum. Meth. B. Revised verison contains minor changes in order to match the published versio

Gamma-spectrometric determination of 232U in uranium-bearing materials

The 232U content of various uranium-bearing items was measured using low-background gamma spectrometry. The method is independent of the measurement geometry, sample form and chemical composition. Since 232U is an artificially produced isotope, it carries information about previous irradiation of the material, which is relevant for nuclear forensics, nuclear safeguards and for nuclear reactor operations. A correlation between the 232U content and 235U enrichment of the investigated samples has been established, which is consistent with theoretical predictions. It is also shown how the correlation of the mass ratio 232U/235U vs. 235U content can be used to distinguish materials contaminated with reprocessed uranium from materials made of reprocessed uranium

Asian Values and Human Rights: A Vietnamese Perspective

This paper examines the impact of the ideology of ‘Asian Values' on the legal norms and practices that frame the recognition and protection of human rights in Vietnam. Specifically, the paper focusses on the extent to which Asian Values has been deployed to discourage the adoption of international human rights norms and practices in the context of Vietnam’s rapid economic development since the mid- 1980s. The paper first sketches the adoption of Asian Values in Vietnam’s politics and society. Cultural and political factors that have shaped the conception of human rights are reviewed. Human rights language and norms, as manifest in political ideologies, policies and laws are then analysed, with particular reference to the different versions of Vietnam’s Constitution. It is shown that both the Communist Party of Vietnam (CPV) and the State of Vietnam have clearly articulated Asian Values in formulating their conceptions of human rights. This outcome is argued to result from the fact that Vietnamese political leaders, alike with Lee Kwan Yew in Singapore, the progenitor of Asian Rights, have been strongly influenced by Confucian ideals of governance. Confucianism is not, however, the only basis for political ideas in Vietnam. Although Vietnam is a market economy it remains a one- party state  controlled  by  the  CPV.  The  Marxist-Leninist  principles  on  which the current State of Vietnam was based at its inception in 1975 remain intact. This ideology was however layered onto generations of collectivist principles embodied in the dominant agrarian society. The influence of Asian Values, on the recognition of and support for human rights in Vietnam has, however, been largely negative rather than positive, especially in relation to recognising civil and political rights as codified in universal human rights instruments. Thus, the protection and promotion of human rights in Vietnam, going forward, essentially mandates eliminating the influence of Asian Values in the ideology of political leaders and in the wider society. Key words: Human rights, Asian Values, democracy, constitution, Communist Party, Vietna

Adsorption of Ammonium (NH4+) Ions onto various Vietnamese biomass residue-derived biochars (wood, rice husk and bamboo)

This study evaluates adsorption of ammonium nitrogen (NH4+-N) ions onto various biochars produced from biomass residues in Vietnam as a function of their physicochemical characteristics. Three biochars, including wood biochar (WBC), rice husk biochar (RBC), and bamboo biochar (BBC), were produced under limited oxygen conditions using Top-Lid Updraft Drum technology at temperatures of 450-550oC. Physicochemical characterization (BET surface area, Cation exchange capacity (CEC), Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy) of the biochars was performed in order to link their porosity and surface functional groups with their NH4+-N capture capacities. Please click on the file below for full content of the abstract

New Viscosity Data for CuO-water Nanofluid -The Hysteresis Phenomenon Revisited

International audienceIn the present work, we have experimentally investigated the stability and hysteresis behaviors of CuO-water nanofluid when submitted to a repeated heating and cooling process. Data has shown that for a low particle volume concentration, 1.6% in particular, the hysteresis phenomenon did not occur for the temperature range considered. For a higher particle concentration, 5% in particular, the hysteresis behaviour was clearly observed when fluid temperature exceeded 52ºC approximately. Beyond this critical temperature, the nanofluid viscosity has increased, and such an increase even continued with a decrease of temperature during the cooling phase. Subsequent measured viscosity and observations in laboratory after the first occurrence of the hysteresis phenomenon have confirmed that the alterations on the particle suspension and on the nanofluid stability appear indeed permanent. Such alterations were found to worsen with further heating/cooling cycles

Multi-micronutrient-fortified biscuits decreased the prevalence of anaemia and improved iron status, whereas weekly iron supplementation only improved iron status in Vietnamese school children

In Vietnam, nutrition interventions do not target school children despite a high prevalence of micronutrient deficiencies. The present randomised, placebo-controlled study evaluated the impact of providing school children (n 403) with daily multiple micronutrient-fortified biscuits (FB) or a weekly Fe supplement (SUP) on anaemia and Fe deficiency. Micronutrient status was assessed by concentrations of Hb, and plasma ferritin (PF), transferrin receptor (TfR), Zn and retinol. After 6 months of intervention, children receiving FB or SUP had a significantly better Fe status when compared with the control children (C), indicated by higher PF (FB: geometric mean 36·9 (95% CI 28·0, 55·4) μg/l; SUP: geometric mean 46·0 (95% CI 33·0, 71·7) μg/l; C: geometric mean 34·4 (95% CI 15·2, 51·2) μg/l; P<0·001) and lower TfR concentrations (FB: geometric mean 5·7 (95% CI 4·8, 6·52) mg/l; SUP: geometric mean 5·5 (95% CI 4·9, 6·2) mg/l; C: geometric mean 5·9 (95% CI 5·1, 7·1) mg/l; P=0·007). Consequently, body Fe was higher in children receiving FB (mean 5·6 (sd 2·2)mg/kg body weight) and SUP (mean 6·1 (sd 2·5)mg/kg body weight) compared with the C group (mean 4·2 (sd 3·3)mg/kg body weight, P<0·001). However, anaemia prevalence was significantly lower only in the FB group (1·0%) compared with the C group (10·4%, P=0·006), with the SUP group being intermediate (7·4%). Children receiving FB had better weight-for-height Z-scores after the intervention than children receiving the SUP (P=0·009). Vitamin A deficiency at baseline modified the intervention effect, with higher Hb concentrations in vitamin A-deficient children receiving FB but not in those receiving the SUP. This indicates that vitamin A deficiency is implicated in the high prevalence of anaemia in Vietnamese school children, and that interventions should take other deficiencies besides Fe into account to improve Hb concentrations. Provision of biscuits fortified with multiple micronutrients is effective in reducing anaemia prevalence in school childre

Diversifying Group Recommendation

Recommender-systems has been a significant research direction in both literature and practice. The core of recommender systems are the recommendation mechanisms, which suggest to a user a selected set of items supposed to match user true intent, based on existing user preferences. In some scenarios, the items to be recommended are not intended for personal use but a group of users. Group recommendation is rather more since group members have wide-ranging levels of interests and often involve conflicts. However, group recommendation endures the over-specification problem, in which the presumingly relevant items do not necessarily match true user intent. In this paper, we address the problem of diversity in group recommendation by improving the chance of returning at least one piece of information that embraces group satisfaction. We proposed a bounded algorithm that finds a subset of items with maximal group utility and maximal variety of information. Experiments on real-world rating datasets show the efficiency and effectiveness of our approach