4,526 research outputs found

    An improved half-life limit of the double beta decay of 94^{94}Zr into the excited state of 94^{94}Mo

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    A search for the double beta decay transition of 94^{94}Zr into the first excited state of 94^{94}Mo has been performed at the Felsenkeller underground laboratory in Dresden, Germany. A 341.1 g zirconium sample with natural isotopic composition has been measured for 43.9 d in an ultra low background gamma spectroscopy setup. No signal has been observed and a new best lower half-life limit is set as 5.2×10195.2\times10^{19} yr (90% CI). This limit is valid for the 0νββ0\nu\beta\beta and 2νββ2\nu\beta\beta decay into excited states of 94^{94}Mo but cannot distinguish between the two modes. Existing limits are improved by 50%

    A Search for various Double Beta Decay Modes of Cd, Te and Zn Isotopes

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    Various double beta decay modes of Cd, Zn and Te isotopes are explored with the help of CdTe and CdZnTe semiconductor detectors. The data set is splitted in an energy range below 1 MeV having a statistics of 134.5 g\cdotd and one above 1 MeV resulting in 532 g\cdotd. No signals were observed in all channels under investigation. New improved limits for the neutrinoless double beta decay of Zn70 of T1/2>1.31016yrsT_{1/2} > 1.3 \cdot 10^{16} yrs (90% CL), the longest standing limit of all double beta isotopes, and 0νβ+\nu\beta^+EC of Te120 of T1/2>2.21016yrsT_{1/2} > 2.2 \cdot 10^{16} yrs (90% CL) are given. For the first time a limit on the half-life of the 2ν\nuECEC of 120^{120}Te of T1/2>9.41015yrsT_{1/2} > 9.4 \cdot 10^{15} yrs (90% CL) is obtained. In addition, limits on 2ν\nuECEC for ground state transitions of Cd106, Cd108 and Zn64 are improved. The obtained results even under rough background conditions show the reliability of CdTe semiconductor detectors for rare nuclear decay searches.Comment: Extended introduction and summar

    Diabetes and kidney cancer: A direct or indirect association?

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    A positive association between diabetes and kidney cancer has been reported in several investigations, but it is unclear whether diabetes or its complications account for this association. Recent advances in estimating direct associations may be useful for elucidating the association between diabetes and kidney cancer. Therefore, we performed a case-control analysis to evaluate whether the direct association between diabetes and kidney cancer is the primary concern in this exposure-outcome relation. Discharge data (with International Classification of Diseases – 9 codes) from 2001 for hospitals throughout Florida were used to construct a case-control population of inpatients aged ≥45 years. Cases (n=1,909) were inpatients with malignant kidney cancer and controls (n=6,451) were inpatients with motor vehicle injuries. Diabetes status was ascertained for cases and controls. Covariates that required adjustment to estimate the total (age, gender, ethnicity, obesity, and smoking) and direct (age, gender, ethnicity, obesity, smoking, hypertension, and kidney disease) associations were identified in a directed acyclic graph. Binary logistic regression was used to estimate the adjusted total and direct odds ratios (ORs) and corresponding 95% confidence intervals (CIs) of kidney cancer for diabetics. The odds of kidney cancer were higher for inpatients with diabetes than inpatients without diabetes when estimating the total association (OR=1.27, 95%CI: 1.10, 1.47) but attenuated when estimating the direct association (OR=1.08, 95%CI: 0.93, 1.25). Our findings provide preliminary insight that the direct association between diabetes and kidney cancer may not be the primary concern in this exposure-outcome relation; indirect pathways (i.e. diabetic complications) may have greater influence on this relation. A similar analysis using longitudinal data with appropriately measured covariates may provide more definitive conclusions and could have implications for kidney cancer prevention among diabetics

    A search for the radiative neutrinoless double electron capture of 58^{58}Ni

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    A search for the radiative neutrinoless double electron capture with single \gray\ emission has been performed in 58^{58}Ni. Gamma radiation from a 7286 g nickel sample in natural isotope composition was measured for 58.3 d with an ultra low background HPGe detector in the Felsenkeller underground laboratory in Dresden, Germany. A new lower half-life limit of 2.1×10212.1 \times 10^{21} yr (90% CL) was obtained for this decay mode. This half-life limit is two orders of magnitude higher than the existing limit for 58^{58}Ni and among the best half-life limits for neutrinoless double electron capture decays

    An alternative search for the electron capture of Te-123

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    A search for the electron capture of Te-123 has been performed using CdZnTe detectors. After a measuring time of 195 h no signal could be found resulting in a lower half-life limt of T1/2>3.21016T_{1/2} > 3.2 \cdot 10^{16} yrs (95 % CL) for this process. This clearly discriminates between existing experimental results which differ by six orders of magnitude and our data are in strong favour of the result with longer half-lifes.Comment: 2 pages, 2 eps-figures, reanalysis of data set

    PHYCOERYTHROCYANINS FROM Westiellopsis prolifica AND Nostoc rivulare: CHARACTERIZATION OF THE PHYCOVIOLOBILIN CHROMOPHORE IN BOTH STATES

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    Phycoerythrocyanin or fractions enriched in it have been isolated from the filamentous cyanobacteria, Westiellopsis prolifica ARM 365 and Nostoc rivulare ARM 212. Both show the photoreversible photochromism (difference maxima at 503 and 570 nm) characteristic of this pigment, which is related to the phycoviolobilin chromophore on the α-subunit. Native phycoerythrocyanin and its β-subunit show little if any reversible photochemistry in the 600–620 nm region, where the phycocyanobilin chromophores absorb maximally. Instead the phycocyanobilin chromophores are bleached irreversibly. At the same time, the data show that reversible photochemistry is a useful analytical tool to detect phycoerythrocyanin in cyanobacterial extracts. Fluorescence measurements indicate that: (i) the 510 nm absorbing isomer of the violobilin chromophore has only little fluorescence; and (ii) the energy transfer from the violobilin chromophores to the cyanin chromophores is efficient only in the 570 nm form

    Double Beta Decays into Excited States in 110^{110}Pd and 102^{102}Pd

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    A search for double beta decays of 110^{110}Pd and 102^{102}Pd into excited states of the daughter nuclides has been performed using three ultra-low background gamma-spectrometry measurements in the Felsenkeller laboratory, Germany, the HADES laboratory, Belgium and at the LNGS, Italy. The combined Bayesian analysis of the three measurements sets improved half-life limits for the 2νββ2\nu\beta\beta and 0νββ0\nu\beta\beta decay modes of the 21+2^+_1, 01+0^+_1 and 22+2^+_2 transitions in 110^{110}Pd to 2.910202.9\cdot10^{20} yr, 4.010204.0\cdot10^{20} yr and 3.010203.0\cdot10^{20} yr respectively and in 102^{102}Pd to 7.610187.6\cdot10^{18} yr, 8.810188.8\cdot10^{18} yr and 1.410191.4\cdot10^{19} yr respectively with 90% credibility
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