Results of the NEMO3 experiment

The purpose of the NEMO3 experiment is to detect neutrinoless double beta decay in order to determine the nature of neutrino and its absolute mass. We analysed the 389 effective days of data from the $\sim 7$ kg of $^{100}$Mo and $\sim 1$ kg of $^{82}$Se and obtained the following limits on the half-life for the \bb process: $T_{1/2}(\beta\beta0 \nu) > 4.6 \times 10^{23}$ years (Mo) and $T_{1/2}(\beta \beta 0 \nu) > 1.0 \times 10^{23}$ years (Se). The corresponding limits on the neutrino effective mass are $<$ 0.7 - 2.8 eV (Mo) and $>$ 1.7 - 4.9 eV (Se) at 90% Confident Level. We also performed a detailled analysis on the double beta decay of $^{100}$Mo into the excited states $0^+_1$, $2^+_1$ of $^{100}$Ru. The results are: $T_{1/2}(\beta \beta 2 \nu \to 0^+_1) = 5.7^{+1.3}_{-0.9}(stat)\pm 0.7 (syst) \times 10^{20}$ years, $T_{1/2}(\beta \beta 2 \nu \to 2^+_1) > 1.1 \times 10^{21}$ years, $T_{1/2}(\beta \beta 0 \nu \to 0^+_1) > 8.9 \times 10^{22}$ years, $T_{1/2}(\beta \beta 0 \nu \to 2^+_1) > 1.6 \times 10^{23}$ years.Comment: 4 pages, 5 figures, Proceeding of the Moriond 2006 EW conferenc

Current rectification by simple molecular quantum dots: an ab-initio study

We calculate a current rectification by molecules containing a conjugated molecular group sandwiched between two saturated (insulating) molecular groups of different length (molecular quantum dot) using an ab-initio non-equilibrium Green's function method. In particular, we study S-(CH2)m-C10H6-(CH2)n-S dithiol with Naphthalene as a conjugated central group. The rectification current ratio ~35 has been observed at m = 2 and n = 10, due to resonant tunneling through the molecular orbital (MO) closest to the electrode Fermi level (lowest unoccupied MO in the present case). The rectification is limited by interference of other conducting orbitals, but can be improved by e.g. adding an electron withdrawing group to the naphthalene.Comment: 8 pages, 9 figure

The Effects of Molybdenum and / or Sulfur Supplementation on the Mineral Status of Plasma and Liver of Sheep Fed Palm Kernel Cake

Although palm kernel cake (PKC) has been widely used as a feed for large ruminant, its high copper (Cu) content is potentially poisonous to sheep and possibly goats. It is well known that sheep are extremely intolerant of Cu toxicity. Sheep fed high levels of PKC, showed high levels of Cu in the liver, which caused jaundice and liver damage. Some studies showed that molybdenum (Mo) and/or sulfur (S) could form complexes with Cu to make Cu unavailable, hence reducing the accumulation in the liver. However, the optimum amount of S and Mo need to be added to PKC has not been established. In the present study, from 80 six months to one-year-old Malin cross sheep, 72 were selected and allocated randomly into 9 groups with 8 animals each. The animals were offered PKC pellet (96-97%) supplemented with different levels of S and Mo, hence, Diet A (Mo, 13ppm), Diet B (Mo, 26ppm), Diet C (52ppm), Diet D (Mo, 1 03ppm), Diet E (S, 4400ppm, Mo, 13ppm), Diet F (S, 4400ppm , Mo, 26ppm), Diet G (S, 4400ppm, Mo, 52ppm), Diet H (S, 4400ppm, Mo, 103ppm), Diet I (S, 4400ppm). The feeding trial lasted 6 months. The animals were slaughtered in two g roups, i.e. , at the end of 3 months and 6 months of the feeding trial respectively. When the animals were slaughtered, their livers were removed, prepared and were analyzed for mineral concentration. The blood was collected from the jugular vein of each sheep in heparinized vacuum tubes and centrifuged to obtain plasma once every 2 months throughout the trial. The plasma was prepared for the analyses of the mineral content and this was carried out by Atomic Absorption Spectrophotometer (AAS). The results showed that Mo when combined with S and Mo alone in high levels were more efficient in reducing the liver Cu levels in sheep than Mo in low levels or S. However, except for Ca, other elements analyzed also showed different variations among treatments and the initial values. The plasma minerals showed some differences from that of liver minerals. Again, except for Ca, other elements presented some changes over time. The causes of the above may be complicated, however, the major reason considered is the dietary treatments. It is evident in this study that Mo and / or S supplementation have prevented the sheep from chronic Cu toxicity as caused by PKC, and the animals survived between 3-6 months of feeding trial. When those treatments were compared, all Mo + S groups seem to be more efficient in lowering the liver Cu levels

Quantitative phase Analisis: A comparative study of Mo and Cu strictly monochromatic radiations

A comparison of the Rietveld quantitative phase analyses (RQPA) obtained using Cu-Kα1, Mo-Kα1, and synchrotron strictly monochromatic radiations is presented. The main aim is to test a simple hypothesis: high energy Mo-radiation, combined with high resolution laboratory X-ray powder diffraction optics, could yield more accurate RQPA, for challenging samples, than well-established Cu-radiation procedure(s). In order to do so, three set of mixtures with increasing amounts of a given phase (spiking-method) were prepared and the corresponding RQPA results have been evaluated. Firstly, a series of crystalline inorganic phase mixtures with increasing amounts of an analyte was studied in order to determine if Mo-Kα1 methodology is as robust as the well-established Cu-Kα1 one. Secondly, a series of crystalline organic phase mixtures with increasing amounts of an organic compound was analyzed. This type of mixture can result in transparency problems in reflection and inhomogeneous loading in narrow capillaries for transmission studies. Finally, a third series with variable amorphous content was studied. Limit of detection in Cu-patterns, ~0.2 wt%, are slightly lower than those derived from Mo-patterns, ~0.3 wt%, for similar recording times and limit of quantification for a well crystallized inorganic phase using laboratory powder diffraction was established ~0.10 wt%. However, the accuracy was comprised as relative errors were ~100%. Contents higher than 1.0 wt% yielded analyses with relative errors lower than 20%. From the obtained results it is inferred that RQPA from Mo-Kα1 radiation have slightly better accuracies than those obtained from Cu-Kα1. This behavior has been established with the calibration graphics obtained through the spiking method and also from Kullback-Leibler distance statistic studies. We explain this outcome, in spite of the lower diffraction power for Mo-radiation (compared to Cu-radiation), due to the larger volume tested with Mo, also because higher energy minimize pattern systematic errors and the microabsorption effect.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Effect of Supplementing Molybdenum, Molybdenum and Sulphur, and Zinc on Mineral Excretion of Sheep Fed with Palm Kernel Cake

Feeding high levels of palm kernel cake (PKC) has been reported to cause copper (Cu) toxicity in sheep. The degree of Cu toxicity is generally dependent on type of sheep breed, the form of Cu in the diets, feeding duration and interaction of Cu with other nutrients. This study was specifically camed out to investigate the effect of molybdenum (Mo), sulphur (S) and zinc (Zn) supplementation on the balance of minerals and to relate the findings with the degree of toxicity in Santa In& x Malin crossbred sheep. Twenty male Santa In& x Malin crossbred sheep from 8 months to 1 year of age were divided randomly into 4 groups. The animals were fed the following diets over the 6 months experimental period, PKC (86.2%); guinea grass hay (10%) supplemented with 30 ppm Mo (diet Mo), 20 ppm Mo +lo00 ppm S (diet Mo+S), . 500 ppm Zn (diet Zn) and the control without supplementation (diet Control). Faecal and urine samples were collected during the digestibility trial for mineral analysis. Mineral contents were also analyzed in blood plasma samples throughout the experiment period as well as from liver, kidney, pancreas and bile collected at slaughter. Mo+S or Mo alone and Zn treatments were observed to reduce the Cu level in the liver, kidney, pancreas and bile of the sheep. But Mo+S is more effective in reducing Cu from those tissues, especially the liver. Plasma minerals results showed that both Zn and Mo+S treatments were more effective in reducing Cu, Fe and Mg levels over time. Based on the results of this study, the hepatic Cu content was found to be higher in control group compared with other treatments. However, Mo+S treatment was found to be more effective in controlling and lowering Cu levels. There were significant effect of dietary supplement of Mo+S, Mo and Zn in increasing the loss of endogenous Cu from the body via faeces and urine

The Low End of the Initial Mass Function in Young LMC Clusters: I. The Case of R136

We report the result of a study in which we have used very deep broadband V and I WFPC2 images of the R136 cluster in the Large Magellanic Cloud from the HST archive, to sample the luminosity function below the detection limit of 2.8 Mo previously reached. In these new deeper images, we detect stars down to a limiting magnitude of m_F555W = 24.7 (~ 1 magnitude deeper than previous works), and identify a population of red stars evenly distributed in the surrounding of the R136 cluster. A comparison of our color-magnitude diagram with recentely computed evolutionary tracks indicates that these red objects are pre-main sequence stars in the mass range 0.6 - 3 Mo. We construct the initial mass function (IMF) in the 1.35 - 6.5 Mo range and find that, after correcting for incompleteness, the IMF shows a definite flattening below ~ 2 Mo. We discuss the implications of this result for the R136 cluster and for our understanding of starburst galaxies formation and evolution in general.Comment: 29 pages, 6 tables, 11 figures included + 3 external files, accepted for publication by Ap.