376 research outputs found

    MERGING THE 21ST CENTURY INTO A GILDED AGE, FORTUNE 500 BOARDROOM

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    Polychrome, gilded, and embossed leather was considered an attractive covering for decorative furnishings and walls in American Gilded Age mansions. These specialty European leathers originally crafted in the 17th and 18th century were either repurposed in the 19th century for the American market or, new versions of them were crafted following evolving 19th century technologies. By the 21st century, with a decreased demand for these decorative leathers, the craft traditions had become a forgotten art. The 2003 decision to replace 1,400 square feet of polychromed embossed leather in a gilded age boardroom presented an opportunity to visit the atelier to discuss and document the decorative finishing process. This presentation shares through a photo essay how one workshop has revived this traditional craft for the 21st century marketplace. Decorated leathers are produced using a combination of traditional techniques and contemporary materials. The presentation will also address how these leathers were prepared and mounted for long-term preservation needs using current materials and methods

    Effects of vitamin D2-fortified bread v. supplementation with vitamin D2 or D3 on serum 25-hydroxyvitamin D metabolites: an 8-week randomised-controlled trial in young adult Finnish women

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    AbstractThere is a need for food-based solutions for preventing vitamin D deficiency. Vitamin D3(D3) is mainly used in fortified food products, although the production of vitamin D2(D2) is more cost-effective, and thus may hold opportunities. We investigated the bioavailability of D2from UV-irradiated yeast present in bread in an 8-week randomised-controlled trial in healthy 20–37-year-old women (n33) in Helsinki (60°N) during winter (February–April) 2014. Four study groups were given different study products (placebo pill and regular bread=0 µg D2or D3/d; D2supplement and regular bread=25 µg D2/d; D3supplement and regular bread=25 µg D3/d; and placebo pill and D2-biofortified bread=25 µg D2/d). Serum 25-hydroxyvitamin D2(S-25(OH)D2) and serum 25-hydroxyvitamin D3(S-25(OH)D3) concentrations were measured at baseline, midpoint and end point. The mean baseline total serum 25-hydroxyvitamin D (S-25(OH)D=S-25(OH)D2+S-25(OH)D3) concentration was 65·1 nmol/l. In repeated-measures ANCOVA (adjusted for baseline S-25(OH)D as total/D2/D3), D2-bread did not affect total S-25(OH)D (P=0·707) or S-25(OH)D3(P=0·490), but increased S-25(OH)D2compared with placebo (P&lt;0·001). However, the D2supplement was more effective than bread in increasing S-25(OH)D2(P&lt;0·001). Both D2and D3supplementation increased total S-25(OH)D compared with placebo (P=0·030 andP=0·001, respectively), but D2supplementation resulted in lower S-25(OH)D3(P&lt;0·001). Thus, D2from UV-irradiated yeast in bread was not bioavailable in humans. Our results support the evidence that D2is less potent in increasing total S-25(OH)D concentrations than D3, also indicating a decrease in the percentage contribution of S-25(OH)D3to the total vitamin D pool.</jats:p

    Background free search for neutrinoless double beta decay with GERDA Phase II

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    The Standard Model of particle physics cannot explain the dominance of matter over anti-matter in our Universe. In many model extensions this is a very natural consequence of neutrinos being their own anti-particles (Majorana particles) which implies that a lepton number violating radioactive decay named neutrinoless double beta (0νββ0\nu\beta\beta) decay should exist. The detection of this extremely rare hypothetical process requires utmost suppression of any kind of backgrounds. The GERDA collaboration searches for 0νββ0\nu\beta\beta decay of 76^{76}Ge (^{76}\rm{Ge} \rightarrow\,^{76}\rm{Se} + 2e^-) by operating bare detectors made from germanium with enriched 76^{76}Ge fraction in liquid argon. Here, we report on first data of GERDA Phase II. A background level of 103\approx10^{-3} cts/(keV\cdotkg\cdotyr) has been achieved which is the world-best if weighted by the narrow energy-signal region of germanium detectors. Combining Phase I and II data we find no signal and deduce a new lower limit for the half-life of 5.310255.3\cdot10^{25} yr at 90 % C.L. Our sensitivity of 4.010254.0\cdot10^{25} yr is competitive with the one of experiments with significantly larger isotope mass. GERDA is the first 0νββ0\nu\beta\beta experiment that will be background-free up to its design exposure. This progress relies on a novel active veto system, the superior germanium detector energy resolution and the improved background recognition of our new detectors. The unique discovery potential of an essentially background-free search for 0νββ0\nu\beta\beta decay motivates a larger germanium experiment with higher sensitivity.Comment: 14 pages, 9 figures, 1 table; ; data, figures and images available at http://www.mpi-hd.mpg/gerda/publi

    The background in the neutrinoless double beta decay experiment GERDA

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    The GERmanium Detector Array (GERDA) experiment at the Gran Sasso underground laboratory (LNGS) of INFN is searching for neutrinoless double beta decay of 76Ge. The signature of the signal is a monoenergetic peak at 2039 keV, the Q-value of the decay, Q_bb. To avoid bias in the signal search, the present analysis does not consider all those events, that fall in a 40 keV wide region centered around Q_bb. The main parameters needed for the neutrinoless double beta decay analysis are described. A background model was developed to describe the observed energy spectrum. The model contains several contributions, that are expected on the basis of material screening or that are established by the observation of characteristic structures in the energy spectrum. The model predicts a flat energy spectrum for the blinding window around Q_bb with a background index ranging from 17.6 to 23.8*10^{-3} counts/(keV kg yr). A part of the data not considered before has been used to test if the predictions of the background model are consistent. The observed number of events in this energy region is consistent with the background model. The background at Q-bb is dominated by close sources, mainly due to 42K, 214Bi, 228Th, 60Co and alpha emitting isotopes from the 226Ra decay chain. The individual fractions depend on the assumed locations of the contaminants. It is shown, that after removal of the known gamma peaks, the energy spectrum can be fitted in an energy range of 200 kev around Q_bb with a constant background. This gives a background index consistent with the full model and uncertainties of the same size

    Limits on uranium and thorium bulk content in GERDA Phase I detectors

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    Internal contaminations of 238^{238}U, 235^{235}U and 232^{232}Th in the bulk of high purity germanium detectors are potential backgrounds for experiments searching for neutrinoless double beta decay of 76^{76}Ge. The data from GERDA Phase~I have been analyzed for alpha events from the decay chain of these contaminations by looking for full decay chains and for time correlations between successive decays in the same detector. No candidate events for a full chain have been found. Upper limits on the activities in the range of a few nBq/kg for 226^{226}Ra, 227^{227}Ac and 228^{228}Th, the long-lived daughter nuclides of 238^{238}U, 235^{235}U and 232^{232}Th, respectively, have been derived. With these upper limits a background index in the energy region of interest from 226^{226}Ra and 228^{228}Th contamination is estimated which satisfies the prerequisites of a future ton scale germanium double beta decay experiment.Comment: 2 figures, 7 page

    2νββ2\nu\beta\beta decay of 76^{76}Ge into excited states with GERDA Phase I

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    Two neutrino double beta decay of 76^{76}Ge to excited states of 76^{76}Se has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in 76^{76}Ge was deployed in liquid argon. The analysis of various possible transitions to excited final states is based on coincidence events between pairs of detectors where a de-excitation γ\gamma ray is detected in one detector and the two electrons in the other. No signal has been observed and an event counting profile likelihood analysis has been used to determine Frequentist 90\,\% C.L. bounds for three transitions: 0g.s.+21+{0^+_{\rm g.s.}-2^+_1}: T1/22ν>T^{2\nu}_{1/2}>1.61023\cdot10^{23} yr, 0g.s.+01+{0^+_{\rm g.s.}-0^+_1}: T1/22ν>T^{2\nu}_{1/2}>3.71023\cdot10^{23} yr and 0g.s.+22+{0^+_{\rm g.s.}-2^+_2}: T1/22ν>T^{2\nu}_{1/2}>2.31023\cdot10^{23} yr. These bounds are more than two orders of magnitude larger than those reported previously. Bayesian 90\,\% credibility bounds were extracted and used to exclude several models for the 0g.s.+01+{0^+_{\rm g.s.}-0^+_1} transition

    Results on ββ\beta\beta decay with emission of two neutrinos or Majorons in 76^{76}Ge from GERDA Phase I

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    A search for neutrinoless ββ\beta\beta decay processes accompanied with Majoron emission has been performed using data collected during Phase I of the GERmanium Detector Array (GERDA) experiment at the Laboratori Nazionali del Gran Sasso of INFN (Italy). Processes with spectral indices n = 1, 2, 3, 7 were searched for. No signals were found and lower limits of the order of 1023^{23} yr on their half-lives were derived, yielding substantially improved results compared to previous experiments with 76^{76}Ge. A new result for the half-life of the neutrino-accompanied ββ\beta\beta decay of 76^{76}Ge with significantly reduced uncertainties is also given, resulting in T1/22ν=(1.926±0.095)1021T^{2\nu}_{1/2} = (1.926 \pm 0.095)\cdot10^{21} yr.Comment: 3 Figure
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