Literatura académica sobre el tema "Changes in beta-decay half-life"
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Artículos de revistas sobre el tema "Changes in beta-decay half-life"
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Alves, Naiane Ferraz Bandeira, Suênia Karla Pacheco Porpino y Alexandre Sérgio Silva. "The period between beta-blocker use and physical activity changes training heart rate behavior". Brazilian Journal of Pharmaceutical Sciences 45, n.º 4 (diciembre de 2009): 729–35. http://dx.doi.org/10.1590/s1984-82502009000400017.
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The Brazilian Society of Cardiology (SBC) proposes that hypertensive subjects who use beta-blockers and practice physical exercises must have their training heart rate (HR) corrected due to the negative chronotropic effect of this drug. Nevertheless, if the physical activity is performed outside of plasmatic half-life, correction may not be necessary. This study investigated the exercise chronotropic response both inside and outside the beta-blocker plasmatic half-life. Nine subjects in use of atenolol or propranolol, and six controls, carried out three walking sessions in three days according to different schedules: EX2 (two hours after drug administration, at the plasmatic peak); EX11 (eleven hours after drug administration, at the end of plasmatic half-life); and EX23 (twenty-three hours after drug administration, outside the plasmatic half-life. The walking sessions were performed on an ergometric treadmill and HR was monitored by a heart rate monitor. During the exercises, mean HRs were 97.2, 108.4 and 109 for EX2, EX11 and EX23, respectively, with the value for EX2 statistically lower than the others (p<0.05). There were no statistical differences in the control group (p>0.05). The study concludes that the attenuation of the positive chronotropic response which occurs during exercise in subjects using beta-blockers, is less evident when the exercise is performed outside the plasmatic half-life of the drug.
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Naderi, D. y M. Zargooshi. "Study of alpha-decay half-lives with deformed, oriented daughter nuclei". International Journal of Modern Physics E 24, n.º 02 (febrero de 2015): 1550010. http://dx.doi.org/10.1142/s021830131550010x.
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In this paper, Coulomb and proximity potential model has been applied to calculate the half-lives of alpha-decay for isotopes around N = Z = 50. Using this model, we investigated the influence of deformation and orientation of daughter nucleus on alpha-decay half-lives. Two orientations (90° and 180°) with quadrupole deformation are applied to study the role of daughter orientation in alpha-decay process. It is found that the deformation and orientation of daughter nucleus affects the alpha-decay half-life and changes the slope and intercept of linear relation between log10(T1/2) and Q-1/2.
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Wang, Jinjuan y James C. Rose. "Developmental changes in renal renin mRNA half-life and responses to stimulation in fetal lambs". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 277, n.º 4 (1 de octubre de 1999): R1130—R1135. http://dx.doi.org/10.1152/ajpregu.1999.277.4.r1130.
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In the perinatal period there is increased renin gene expression in the kidney compared with other stages of development. This may be related to changes in responsiveness of the renin gene to stimulation and/or differences in renin mRNA stability as development progresses. To ascertain if either responsiveness or stability changes in fetal life, we studied renin mRNA levels in primary cultures of renal cortical cells obtained from fetal lamb kidneys at two stages (0.7 and 0.9) of gestation after stimulation with isoproterenol, forskolin, or isobutyl methylxanthine and after inhibition of transcription with actinomycin D. Forskolin and isobutyl methylxanthine rapidly increased renin mRNA by at least twofold in the cultured cells from fetuses of both ages, with the sensitivity to stimulation higher in the cells from the mature fetal kidneys. Isoproterenol was effective only in mature fetal cells. In addition, the decay of renin mRNA after cessation of transcription was slower in mature cells compared with immature cells, the half-life being 11.6 ± 0.8 h in mature cells and 6.6 ± 0.6 h in immature cells ( P < 0.05). The data suggest that increases in both renin mRNA sensitivity to stimulation and in stability can contribute to the enhanced renin expression in the perinatal period.
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K. P. Anjali, K. Prathapan, R. K. Biju y K. P. Santhosh. "A Systematic Study on the Existence of 7-9B, 16-19Ne, 8-11C, 23-30P and 26-32S Nuclei via Cluster Decay in the Super Heavy Region". Journal of Nuclear Physics, Material Sciences, Radiation and Applications 7, n.º 1 (13 de agosto de 2019): 1–12. http://dx.doi.org/10.15415/jnp.2019.71001.
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Based on the Coulomb and Proximity Potential Model, we have studied the decay probabilities of various exotic nuclei from even-even nuclei in the super heavy region. The half-lives and barrier penetrability for the decay of exotic nuclei such as 7-9B, 16-19 Ne, 8-11 C, 23-30 P and 26-32 S from the isotopes 274-332116,274-334 118 and 288-334120 are determined by considering them as spherical as well as deformed nuclei. The effect of ground state quadrupole (β2), Octupole (β3) and hexadecapole (β4) deformation of parent, daughter and cluster nuclei on half- lives and barrier penetrability were studied. Calculations have done for the spherical nuclei and deformed nuclei in order to present the effects of the deformations on half-lives. It is found that height and shape of the barrier reduces by the inclusion of deformation and hence half-life for the emission of different clusters decreases and barrierpenetrability increases. Changes in the half-lives with and without the inclusion of deformation effects are compared in the graph of half -life and barrier penetrability against neutron number of parents. It is evident from the computed half lives that many of the exotic nuclei emissions are probable. Moreover shell structure effects on the half-lives of decay are evident from these plots. Peak in the plot of halflife and dip in the plot of barrier penetrability against neutron number of parent show shell closure at or near to N=184, N=200 and N=212.
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Chambers, SK, M. Gilmore-Hebert, BM Kacinski y EJ Jr Benz. "Changes in Na,K-ATPase gene expression during granulocytic differentiation of HL60 cells". Blood 80, n.º 6 (15 de septiembre de 1992): 1559–64. http://dx.doi.org/10.1182/blood.v80.6.1559.1559.
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Abstract During granulocytic differentiation of HL60 cells, immediate reduction of ouabain-sensitive potassium flux is observed within the first 12 hours of addition of dimethyl sulfoxide (DMSO). We show that gene expression of the alpha 3 isoform of Na+,K(+)-ATPase, which encodes an ouabain-inhibitable Na+,K(+)-ATPase activity, significantly declines during the first 24 hours of granulocytic differentiation by DMSO of HL60 cells. The more common alpha 1 isoform decreases, but more gradually over 72 hours of DMSO induction. Loss of alpha 3 and alpha 1 messenger RNA (mRNA) are due to changes in mRNA decay; their transcription is not altered. alpha 3 mRNA half-life is 3 hours in HL60 cells; upon induction by 16 hours of DMSO, it decreases to approximately 2 hours. alpha 1 transcripts are less sensitive to DMSO induction, with their half-life being 3.5 hours in HL60 cells; upon induction, their half-life decreases to 3 hours. Experiments measuring protein stability confirm that alpha 3 protein is more labile than alpha 1. In uninduced HL60 cells, alpha 3 membrane protein comprises 30% of the total alpha isoforms, and is less stable than alpha 1, with a protein half-life of only 9 hours. Upon DMSO induction, steady-state alpha 3 protein decreases markedly within 10 hours, whereas alpha 1 protein remains stable. These results show that posttranscriptional changes during induction play a major role in the differential regulation of alpha 1 and alpha 3 isoforms of Na+,K(+)-ATPase; regulation of the latter may be important for early granulocytic differentiation, or for one of the differentiated functions of mature granulocytes.
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Chambers, SK, M. Gilmore-Hebert, BM Kacinski y EJ Jr Benz. "Changes in Na,K-ATPase gene expression during granulocytic differentiation of HL60 cells". Blood 80, n.º 6 (15 de septiembre de 1992): 1559–64. http://dx.doi.org/10.1182/blood.v80.6.1559.bloodjournal8061559.
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During granulocytic differentiation of HL60 cells, immediate reduction of ouabain-sensitive potassium flux is observed within the first 12 hours of addition of dimethyl sulfoxide (DMSO). We show that gene expression of the alpha 3 isoform of Na+,K(+)-ATPase, which encodes an ouabain-inhibitable Na+,K(+)-ATPase activity, significantly declines during the first 24 hours of granulocytic differentiation by DMSO of HL60 cells. The more common alpha 1 isoform decreases, but more gradually over 72 hours of DMSO induction. Loss of alpha 3 and alpha 1 messenger RNA (mRNA) are due to changes in mRNA decay; their transcription is not altered. alpha 3 mRNA half-life is 3 hours in HL60 cells; upon induction by 16 hours of DMSO, it decreases to approximately 2 hours. alpha 1 transcripts are less sensitive to DMSO induction, with their half-life being 3.5 hours in HL60 cells; upon induction, their half-life decreases to 3 hours. Experiments measuring protein stability confirm that alpha 3 protein is more labile than alpha 1. In uninduced HL60 cells, alpha 3 membrane protein comprises 30% of the total alpha isoforms, and is less stable than alpha 1, with a protein half-life of only 9 hours. Upon DMSO induction, steady-state alpha 3 protein decreases markedly within 10 hours, whereas alpha 1 protein remains stable. These results show that posttranscriptional changes during induction play a major role in the differential regulation of alpha 1 and alpha 3 isoforms of Na+,K(+)-ATPase; regulation of the latter may be important for early granulocytic differentiation, or for one of the differentiated functions of mature granulocytes.
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Roslund, Marja I., Mira Grönroos, Anna-Lea Rantalainen, Ari Jumpponen, Martin Romantschuk, Anirudra Parajuli, Heikki Hyöty, Olli Laitinen y Aki Sinkkonen. "Half-lives of PAHs and temporal microbiota changes in commonly used urban landscaping materials". PeerJ 6 (19 de marzo de 2018): e4508. http://dx.doi.org/10.7717/peerj.4508.
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Background Polycyclic aromatic hydrocarbons (PAHs) accumulate in urban soils, and PAH contamination can change soil microbial community composition. Environmental microbiota is associated with human commensal microbiota, immune system and health. Therefore, studies investigating the degradation of PAHs, and the consequences of soil pollution on microbial communities in urban landscaping materials, are crucial. Methods Four landscaping materials (organic matter 1, 2, 13 and 56%) were contaminated with PAHs commonly found at urban sites (phenanthrene, fluoranthene, pyrene, chrysene and benzo(b)fluoranthene) in PAH concentrations that reflect urban soils in Finland (2.4 µg g -1 soil dry weight). PAHs were analyzed initially and after 2, 4, 8 and 12 weeks by gas chromatography-mass spectrometry. Half-lives of PAHs were determined based on 12-weeks degradation. Bacterial communities were analyzed at 1 and 12 weeks after contamination using Illumina MiSeq 16S rRNA gene metabarcoding. Results Half-lives ranged from 1.5 to 4.4 weeks for PAHs with relatively low molecular weights (phenanthrene, fluoranthene and pyrene) in landscaping materials containing 1–2% organic matter. In contrast, in materials containing 13% and 56% organic matter, the half-lives ranged from 2.5 to 52 weeks. Shorter half-lives of phenanthrene and fluoranthene were thus associated with low organic matter content. The half-life of pyrene was inversely related to the relative abundance of Beta-, Delta- and Gammaproteobacteria, and diversity of Bacteroidetes and Betaprotebacteria. Compounds with higher molecular weights followed compound-specific patterns. Benzo(b)fluoranthene was resistant to degradation and half-life of chrysene was shorter when the relative abundance of Betaproteobacteria was high. Temporal microbiota changes involved increase in the relative abundance of Deltaproteobacteria and decrease in genera Flavobacterium and Rhodanobacter. Exposure to PAHs seems to adjust microbial community composition, particularly within class Beta- and Deltaproteobacteria. Conclusions In this study, PAH degradation depended on the organic matter content and bacterial community composition of landscaping materials. Contamination seems to alter bacterial community composition in landscaping materials depending on material type. This alteration includes changes in bacterial phyla associated with human health and immune system. This may open new possibilities for managing urban environments by careful selection of landscaping materials, to benefit health and wellbeing.
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Ehlers, B., J. Czichos y P. Overath. "RNA turnover in Trypanosoma brucei." Molecular and Cellular Biology 7, n.º 3 (marzo de 1987): 1242–49. http://dx.doi.org/10.1128/mcb.7.3.1242.
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Regulation of variant surface glycoprotein (VSG) mRNA turnover in Trypanosoma brucei was studied in bloodstream forms, in procyclic cells, and during in vitro transformation of bloodstream forms to procyclic cells by approach-to-equilibrium labeling and pulse-chase experiments. Upon initiation of transformation at 27 degrees C in the presence of citrate-cis-aconitate, the half-life of VSG mRNA was reduced from 4.5 h in bloodstream forms to 1.2 h in transforming cells. Concomitantly, an approximately 25-fold decrease in the rate of transcription was observed, resulting in a 100-fold reduction in the steady-state level of de novo-synthesized VSG mRNA. This low level of expression was maintained for at least 7 h, finally decreasing to an undetectable level after 24 h. Transcription of the VSG gene in established procyclic cells was undetectable. For comparison, the turnover of polyadenylated and nonpolyadenylated RNA, beta-tubulin mRNA, and mini-exon-derived RNA (medRNA) was studied. For medRNA, no significant changes in the rate of transcription or stability were observed during differentiation. In contrast, while the rate of transcription of beta-tubulin mRNA in in vitro-cultured bloodstream forms, transforming cells, and established procyclic cells was similar, the half life was four to five times longer in procyclic cells (t1/2, 7 h) than in cultured bloodstream forms (t1/2, 1.4 h) or transforming cells (t1/2, 1.7 h). Inhibition of protein synthesis in bloodstream forms at 37 degrees Celsius caused a dramatic 20-fold decrease in the rate of VSG mRNA synthesis and a 6-fold decrease in half-life to 45 min, while beta-tubulin mRNA was stabilized 2- to 3-fold and mRNA stability remained unaffected. It is postulated that triggering transformation or inhibiting protein synthesis induces changes in the abundance of the same regulatory molecules which effect the shutoff of VSG gene transcription in addition to shortening the half-life of VSG mRNA.
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Ehlers, B., J. Czichos y P. Overath. "RNA turnover in Trypanosoma brucei". Molecular and Cellular Biology 7, n.º 3 (marzo de 1987): 1242–49. http://dx.doi.org/10.1128/mcb.7.3.1242-1249.1987.
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Regulation of variant surface glycoprotein (VSG) mRNA turnover in Trypanosoma brucei was studied in bloodstream forms, in procyclic cells, and during in vitro transformation of bloodstream forms to procyclic cells by approach-to-equilibrium labeling and pulse-chase experiments. Upon initiation of transformation at 27 degrees C in the presence of citrate-cis-aconitate, the half-life of VSG mRNA was reduced from 4.5 h in bloodstream forms to 1.2 h in transforming cells. Concomitantly, an approximately 25-fold decrease in the rate of transcription was observed, resulting in a 100-fold reduction in the steady-state level of de novo-synthesized VSG mRNA. This low level of expression was maintained for at least 7 h, finally decreasing to an undetectable level after 24 h. Transcription of the VSG gene in established procyclic cells was undetectable. For comparison, the turnover of polyadenylated and nonpolyadenylated RNA, beta-tubulin mRNA, and mini-exon-derived RNA (medRNA) was studied. For medRNA, no significant changes in the rate of transcription or stability were observed during differentiation. In contrast, while the rate of transcription of beta-tubulin mRNA in in vitro-cultured bloodstream forms, transforming cells, and established procyclic cells was similar, the half life was four to five times longer in procyclic cells (t1/2, 7 h) than in cultured bloodstream forms (t1/2, 1.4 h) or transforming cells (t1/2, 1.7 h). Inhibition of protein synthesis in bloodstream forms at 37 degrees Celsius caused a dramatic 20-fold decrease in the rate of VSG mRNA synthesis and a 6-fold decrease in half-life to 45 min, while beta-tubulin mRNA was stabilized 2- to 3-fold and mRNA stability remained unaffected. It is postulated that triggering transformation or inhibiting protein synthesis induces changes in the abundance of the same regulatory molecules which effect the shutoff of VSG gene transcription in addition to shortening the half-life of VSG mRNA.
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Bai, Taoping, Yu Chen, Wentao Jiang, Fei Yan y Yubo Fan. "Studies on Foam Decay Trend and Influence of Temperature Jump on Foam Stability in Sclerotherapy". Vascular and Endovascular Surgery 52, n.º 2 (26 de noviembre de 2017): 98–106. http://dx.doi.org/10.1177/1538574417741786.
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Objectives: This study investigated the influence of temperature jump and liquid–gas ratio on foam stability to derive the foam-decay law. Methods: The experimental group conditions were as follows: mutation temperatures (10°C, 16°C, 20°C, 23°C, 25°C, and 27°C to >37°C) and liquid–gas ratios (1:1, 1:2, 1:3, and 1:4). The control group conditions were as follows: temperatures (10°C, 16°C, 20°C, 23°C, 25°C and 27°C) and liquid–gas ratios (1:1, 1:2, 1:3, and 1:4). A homemade device manufactured using the Tessari DSS method was used to prepare the foam. The decay process was videotape recorded. In the drainage rate curve, the temperature rose, and the liquid–gas ratio varied from 1:1 to 1:4, causing faster decay. Results: In the entire process, the foam volume decreased with increasing drainage rate. The relationships were almost linear. Comparison of the experimental and control groups shows that the temperature jump results in a drainage time range of 1 to 15 seconds. The half-life ranges from 10 to 30 seconds. The maximum rate is 18.85%. Changes in the preparation temperature yields a drainage time range of 3 to 30 seconds. The half-life varies from 20 to 60 seconds. Conclusion: Decreasing the temperature jump range and liquid–gas ratio gradually enhances the foam stability. The foam decay time and drainage rate exhibit an exponential function distribution.
Tesis sobre el tema "Changes in beta-decay half-life"
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Fatemi-Ghomi, Nasim. "Measurement of the double beta decay half-life of 150Nd and search for neutrinoless decay modes with the NEMO-3 detector". Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496229.
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The half-life for two-neutrino double beta decay of ¹⁵⁰Nd has been measured with data taking by the NEMO 3 experiment at the Modane Underground Laboratory. Using 924.7 days of data recorded with 36.55 g of ¹⁵⁰Nd the half-life of this process is measured ... this result has significantly improved the previous limit on neutrinoless double beta decay of this isotope. Limits are also set on several other neutrinoless double decay modes.
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Caballero, Folch Roger. "First measurement of beta-decay half-lives and neutron emission probabilities in several isotopes beyond N = 126". Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/299373.
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In this work beta-decay half-lives and neutron-emission probability values have been experimentally determined for first time in several nuclei beyond the neutron-shell closure at N=126. To this aim the accelerator complex at the GSI center for heavy ion research (Germany), in combination with the FRS fragment separator, were employed. The beta-decay detection system consisted of a charged particle detector named SIMBA, which served to detect both ion and beta-particles, surrounded by an array of He-3 based neutron counters named BELEN. The half-life values of eighteen isotopes of Au, Hg, Tl, Pb and Bi were determined, as well as the neutron-branching ratios (or upper limits) for seven nuclei. A comparison of the present results with previous half-life measurements in this mass-region shows a generally good agreement, thus reflecting the systematic validity of the decay data available in this region. Compared to theoretical models, our results show a reasonable agreement for half of the analyzed isotopes, and large discrepancies of up to a factor of 10 for the other half. The measured neutron-branching ratios represent the first set of experimental data available in this mass-region for several isotopes. Owing to the absence of previous experimental results, the values reported here can be only compared with theoretical predictions. In summary, a fair compatibility is found between FRDM+QRPA calculations, which however are underestimating by a factor of 5 the neutron-branching ratio of Tl-215, which is the most exotic nucleus measured in this work.En aquest treball s'han determinat, experimentalment i per primera vegada, vides mitjanes i valors de probabilitat d'emissió de neutrons de diversos nuclis amb més de 126 neutrons. Per tal d'obtenir les dades es va realitzar un experiment a les instal·lacions del centre d’investigació d'ions pesats GSI a (Alemanya), combinat amb el separador de fragments FRS. El sistema de detecció d'ions i desintegracions beta va consistir d'un detector de partícules carregades anomenat SIMBA, que estava envoltat per una matriu de comptadors proporcionals d’'He-3 que conformen el detector de neutrons BELEN. En total s'han determinat valors de vida mitjana de divuit isòtops d'or, mercuri, tal·li, plom i bismut, així com també la probabilitat d'emissió de neutrons (o llindars superiors) de set d'ells. Comparant els resultats amb les mesures de vides mitjanes anteriors en aquesta regió de nuclis s'observa un bon acord, reflectint la validesa de la sistemàtica de les dades existents. D’'altra banda, fent la comparació amb els models teòrics, els resultats mostren un acord raonable per la meitat dels isòtops analitzats, i grans discrepàncies, de fins a un factor 10, per l'altra meitat. Pel que fa a les probabilitats d'emissió de neutrons mesurades, essent la primera mesura experimental a la regió per a diversos nuclis, no és possible comparar amb altres els valors obtinguts. La única comparació que es pot avaluar és amb les prediccions teòriques. En resum, els resultats són compatibles amb el model FRDM + QRPA, no obstant s'observen discrepàncies considerables en alguns isòtops de fins a un factor 5, com és el cas del valor obtingut per Tl-215, que correspon al nucli més exòtic del qual s'’ha determinat la probabilitat d’'emissió de neutrons.
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Narro, Joaquin Garces. "Fermi superallowed β+- decays in heavy odd-odd, N = Z nuclei". Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/842872/.
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The beta+-decay half-lives of the neutron-deficient, odd-odd, N = Z nuclei, 74Rb, 78Y, 82NB and 86Tc were measured following the fragmentation of a primary 92Mo beam at an energy of 60 MeV per nucleon at the GANIL laboratory, France. They were measured by correlating beta+-decays with the implantation of unambiguously identified fragments. The deduced log10 ft1/2-values are consistent with 0+→ 0+, Fermi superallowed transitions, which together with the measured beta+-detection efficiencies suggest T = 1, 1pi- 0+ ground states for these odd-odd, N = Z nuclei. These data represent the heaviest N = Z systems for which Fermi superallowed decays have been established. The results suggest that these nuclei can be used to extend the mass range used to test the Conserved Vector Current hypothesis of the standard model. In addition, an experiment using the reaction 58Ni + 28Si at a beam energy of 200 MeV was performed at the Laboratorio Nationale di Legnaro, Italy, using the EUROBALL spectrometer together with a charged particle silicon detector ball and an array of liquid scintillator neutron detectors. The measured values of the energies of the evaporated, charged-particles and those of the gamma-ray multiplicity (deduced using the liquid scintillator detectors), are used to implement a novel technique for the channel selection of weakly populated evaporation channels.
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King, Shiva. "Measurement of the double beta decay half-life of ¹⁰⁰Mo to the 0⁺₁ excited state, and ⁴⁸Ca to the ground state in the NEMO 3 experiment". Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/15784/.
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NEMO 3 is a double beta decay experiment situated in the Fréjus tunnel which runs between France and Italy. If neutrinoless double beta decay is observed it will prove the neutrino is a Majorana particle and may potentially become the most sensitive method of measuring the absolute neutrino mass. It would also have huge implications for not only particle physics, but also nuclear physics, astrophysics and cosmology. The study of two-neutrino double beta decay gives us a better understanding of the nuclear models used to calculate the nuclear matrix elements, which are so important in extracting new physics parameters from the neutrinoless double beta decay search. The purpose of this thesis is primarily to report on the measurement of the two neutrino double beta decay of two isotopes, ^{100}Mo and ^{48}Ca, currently inside the NEMO 3 detector. The double decay of ^{100}Mo to the O^{+}_{1} excited state of ^{100}Ru is studied as well as the double beta decay of ^{48}Ca to the ground state of ^{48}Ti. The two neutrino half-life measurement for ^{100}Mo is found to be T^{2\upsilon}_{1/2}(O^+\rightarrow O^{+}_1}) = 5.70^{+1.15}_{-0.82} (stat) \pm 0.77 (syst.) \times 10^{20} yrs. This being the first result where all the final states have been measured. For ^{48}Ca, the two neutrino half-life is T^{2\upsilon}_{1/2}(g.s. \rightarrow g.s.) = 4.44^{+0.49}_{-0.40}(stat.) \pm 0.29 (syst.) \times 10^{19} yrs, which is the worlds most accurate measurement of this decay process. A limit on the neutrinoless double beta decay of ^{48}Ca has also been obtained.
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Wagner, Victoria Elisabeth [Verfasser] y Manfred [Akademischer Betreuer] Lindner. "Pulse Shape Analysis for the GERDA Experiment to Set a New Limit on the Half-life of Neutrinoless Double Beta Decay of Ge-76 / Victoria Elisabeth Wagner ; Betreuer: Manfred Lindner". Heidelberg : Universitätsbibliothek Heidelberg, 2017. http://d-nb.info/1180739833/34.
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Naaf, Tobias. "Floristic homogenization and impoverishment : herb layer changes over two decades in deciduous forest patches of the Weser-Elbe region (NW Germany)". Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5244/.
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Human-induced alterations of the environment are causing biotic changes worldwide, including the extinction of species and a mixing of once disparate floras and faunas. One type of biological communities that is expected to be particularly affected by environmental alterations are herb layer plant communities of fragmented forests such as those in the west European lowlands. However, our knowledge about current changes in species diversity and composition in these communities is limited due to a lack of adequate long-term studies.
In this thesis, I resurveyed the herb layer communities of ancient forest patches in the Weser-Elbe region (NW Germany) after two decades using 175 semi-permanent plots. The general objectives were (i) to quantify changes in plant species diversity considering also between-community (β) and functional diversity, (ii) to determine shifts in species composition in terms of species’ niche breadth and functional traits and (iii) to find indications on the most likely environmental drivers for the observed changes. These objectives were pursued with four independent research papers (Chapters 1-4) whose results were brought together in a General Discussion.
Alpha diversity (species richness) increased by almost four species on average, whereas β diversity tended to decrease (Chapter 1). The latter is interpreted as a beginning floristic homogenization. The observed changes were primarily the result of a spread of native habitat generalists that are able to tolerate broad pH and moisture ranges. The changes in α and β diversity were only significant when species abundances were neglected (Chapters 1 and 2), demonstrating that the diversity changes resulted mainly from gains and losses of low-abundance species. This study is one of the first studies in temperate Europe that demonstrates floristic homogenization of forest plant communities at a larger than local scale.
The diversity changes found at the taxonomic level did not result in similar changes at the functional level (Chapter 2). The likely reason is that these communities are functionally “buffered”. Single communities involve most of the functional diversity of the regional pool, i.e., they are already functionally rich, while they are functionally redundant among each other, i.e., they are already homogeneous.
Independent of taxonomic homogenization, the abundance of 30 species decreased significantly (Chapter 4). These species included 12 ancient forest species (i.e., species closely tied to forest patches with a habitat continuity > 200 years) and seven species listed on the Red List of endangered plant species in NW Germany. If these decreases continue over the next decades, local extinctions may result. This biotic impoverishment would seriously conflict with regional conservation goals.
Community assembly mechanisms changed at the local level particularly at sites that experienced disturbance by forest management activities between the sampling periods (Chapter 3). Disturbance altered community assembly mechanisms in two ways: (i) it relaxed environmental filters and allowed the coexistence of different reproduction strategies, as reflected by a higher diversity of reproductive traits at the time of the resurvey, and (ii) it enhanced light availability and tightened competitive filters. These limited the functional diversity with respect to canopy height and selected for taller species.
Thirty-one winner and 30 loser species, which had significantly increased or decreased in abundance, respectively, were characterized by various functional traits and ecological performances to find indications on the most likely environmental drivers for the observed floristic changes (Chapter 4). Winner species had higher seed longevity, flowered later in the season and had more often an oceanic distribution compared to loser species. Loser species tended to have a higher specific leaf area, to be more susceptible to deer browsing and to have a performance optimum at higher soil pH values compared to winner species. Multiple logistic regression analyses indicated that disturbances due to forest management interventions were the primary cause of the species shifts. As one of the first European resurvey studies, this study provides indications that an enhanced browsing pressure due to increased deer densities and increasingly warmer winters are important drivers. The study failed to demonstrate that eutrophication and acidification due to atmospheric deposition substantially drive herb layer changes. The restriction of the sample to the most base-rich sites in the region is discussed as a likely reason. Furthermore, the decline of several ancient forest species is discussed as an indication that the forest patches are still paying off their “extinction debt”, i.e., exhibit a delayed response to forest fragmentation.Umweltveränderungen beeinträchtigen weltweit die Artenvielfalt. Die Lebensgemeinschaften fragmentierter Lebensräume gelten als besonders anfällig für Veränderungen. In dieser Arbeit wurden Untersuchungen an Krautschichtgemeinschaften historisch alter Waldfragmente im Elbe-Weser-Dreieck nach zwei Jahrzehnten wiederholt. Ziel war es anhand von 175 semi-permanenten Aufnahmeflächen (i) die Veränderungen der Pflanzenartendiversität zu quantifizieren, (ii) Artenverschiebungen in Bezug auf Nischenbreite und funktionale Merkmale festzustellen und (iii) Hinweise auf die verantwortlichen Umweltveränderungen zu finden. Die α-Diversität (Artenzahl) stieg durchschnittlich um vier Arten an. Die β-Diversität (Artenturnover zwischen den Flächen) nahm tendenziell ab. Letzteres wird als Beginn einer floristischen Homogenisierung interpretiert. Diese Studie ist eine der ersten im gemäßigten Europa, die eine floristische Homogenisierung von Waldpflanzengemeinschaften auf einer größeren als der lokalen Ebene aufzeigt. Die Diversitätsveränderungen auf taxonomischer Ebene führten nicht zu ähnlichen Veränderungen auf funktionaler Ebene. Bereits einzelne Gemeinschaften wiesen den Großteil der funktionalen Vielfalt des regionalen Artenpools, also ein Maximum an funktionaler Diversität auf. Gleichzeitig waren sie untereinander funktional redundant, also bereits homogen. Die mit der beginnenden taxonomischen Homogenisierung verbundene floristische Verarmung wird als gering eingestuft, da die Homogenisierung primär das Ergebnis der Zuwanderung häufig vorkommender Standortgeneralisten war. Unabhängig von der Homogenisierung gingen 30 Arten signifikant in ihrer Abundanz zurück, darunter 12 an historisch alte Wälder gebundene Arten sowie sieben Rote-Liste-Arten. Ein weiterer Rückgang oder ein lokales Aussterben dieser Arten stünde im Widerspruch zu regionalen Naturschutzzielen. Nullmodelltests und der Vergleich funktionaler und taxonomischer Diversitätskomponenten lassen auf regionaler Ebene auf eine zeitliche Konstanz der grundlegenden Mechanismen der Artenvergesellschaftung schließen. Auf der lokalen Ebene veränderten sich die Vergesellschaftungsmechanismen erheblich, insbesondere auf forstwirtschaftlich gestörten Standorten. Einerseits ermöglichte dort eine Abschwächung der Umweltfilter die Koexistenz von Arten mit unterschiedlichen Reproduktionsstrategien. Andererseits führte die erhöhte Lichtverfügbarkeit zu einer Verstärkung der Konkurrenzfilter und einer Selektion hochwüchsiger Arten. Gewinner- und Verliererarten wurden anhand funktionaler Merkmale und ihres ökologischen Verhaltens charakterisiert, um Hinweise auf die verantwortlichen Umweltveränderungen zu finden. Gewinnerarten wiesen eine höhere Langlebigkeit der Samen auf, blühten später in der Vegetationsperiode und hatten öfter eine ozeanische Verbreitung. Verliererarten hatten eine höhere spezifische Blattfläche, einen höheren Attraktivitätswert als Wildäsung und ein ökologisches Optimum bei höheren pH-Werten. Logistische Regressionsanalysen zeigen, dass Störung durch forstwirtschaftliche Eingriffe hauptverantwortlich für die Artenverschiebungen war. Zusätzlich liefert diese Wiederholungsstudie als eine der ersten in Europa Hinweise darauf, dass ein erhöhter Äsungsdruck sowie zunehmend mildere Winter entscheidende Einflussfaktoren darstellen. Der Rückgang mehrerer an historisch alte Wälder gebundener Arten wird als Anzeichen für eine verspätete Reaktion auf die Waldfragmentierung diskutiert.
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Guerin, Hugo. "Développement d'un refroidisseur-regroupeur quadripolaire radiofréquence pour PIPERADE et mesure de la demi-vie de 17F". Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0306/document.
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La future installation SPIRAL2 du GANIL, à Caen, permettra de produire une gamme étendue de noyaux exotiques avec des intensités très importantes. Cependant, ces faisceaux ne pourront pas être directement utilisés pour réaliser certaines études de haute précision et devront d'abord être purifiés. C'est pour réaliser ce travail que des équipes du CENBG, du MPIK (Heidelberg), du CSNSM, du LPC Caen, du GANIL et de l'IPNO développent un double-piège de Penning dans le cadre du projet PIPERADE. Ce double-piège nécessitant un travail de mise en forme préalable du faisceau (diminution de l'émittance transverse et mise en paquet), le CENBG est en charge de la réalisation d'un refroidisseur-regroupeur quadripolaire radiofréquence : le GPIB. C'est ce développement qui a constitué la majeure partie de mon travail de thèse, notamment en ce qui concerne les simulations de ce refroidisseur-regroupeur dont les résultats ont permis de trouver une méthode innovante pour la mise en paquet et de valider sa conception mécanique. Nous disposons également d'une source d'ions afin de pouvoir tester le GPIB et le double-piège et il m'a fallu la remonter, la comprendre et la caractériser pour que ces tests soient ensuite possibles. Dans un second temps j'ai aussi participer à l'analyse de l'expérience E622S menée au GANIL et qui avait pour but de déterminer précisément la demi-vie de 17F. Ce travail n'a pas permis d'améliorer la précision sur la demi-vie de 17F mais nous avons cependant quelques doutes sur les 2 précédentes mesures et sur leur détermination du taux de contamination de leurs échantillonsThe future SPIRAL2 installation of GANIL, at Caen, will produce large range of exotic nuclei with very high intensities. Nevertheless, these beams could not be used directly for some high precision studies and will have to be purified first. To achieve this work, teams of CENBG, MPIK (Heidelberg), CSNSM, LPC Caen, GANIL and IPNO develop a double Penning trap in the framework of the PIPERADE project. Because this double Penning-trap needs some shaping work (reduction of transverse emittance and bunching), the CENBG team is in charge of the realisation of a radio-frequency quadrupole cooler and buncher : the GPIB. This developpement work was the main part of my PhD work, especially for the simulations of this cooler buncher whose results lead us to find a new bunching method and allowed us to approve its mechanical design. We also have an ion source to be able to test both GPIB and Penning trap and I had to reassemble it, to understand it and to characterise it before these tests could be achieved. In a second time I also took part to the analysis of the E622S experiment which aimed to determined precisely the 17F half-life. This work did not lead to a more precise determination of this half-life but we now have some doubts concerning the 2 last measurements and their way to determine the contamination rate of their radioactive samples
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Sepa, Anneli. "The Stress Hypothesis : Implications for the induction of diabetes-related autoimmunity in children?" Doctoral thesis, Linköping : Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5177.
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Goodwin, John 1953. "Can Environmental Factors Affect Half-Life in Beta-Decay? An Analysis". Thesis, 2012. http://hdl.handle.net/1969.1/148338.
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Early in the history of the field of nuclear science, experiments were performed to ascertain whether the half-lives of the radioactive substances being studied – isotopes then called the “radium emanation” [222Rn], “radium A” [218Po], “radium B” [214Pb], and “radium C” [214Bi] - were dependent upon any external factors. At that time, the external factors deemed most likely to affect half-life were temperature and pressure. After several experiments, designed to pick up any change in half-life in the course of changing temperature or pressure, had failed to find any significant changes, it was concluded that half-life does not depend on the physical properties of external environment. And that was the state of the field for a long time - for almost 100 years, in fact.
Fairly recently, however, half-life measurements were recorded, and published, that seemed to show a change in half-life at the few percent level for certain radioactive nuclides which were exposed to extremes of temperature - thus challenging the long-held belief in the unchangeability of half-lives. In addition to half-life changes caused by temperature change, other experiments seemed to find half-life changes caused by other external influences, including the chemical environment of the decaying radioactive nuclide, and even the distance between Earth and the Sun at the time of the half-life measurement.
In this study we present evidence that the initial beliefs in the immutability of radioactive half-life (with the exception of a few nuclides decaying by electron capture whose orbital electrons are involved in both the decay and also in the chemical bonding of those nuclides) is indeed correct; we have done this by performing precise half-life measurements on the β− emitter 198Au, the EC emitter 97Ru, and on the β− emitter 198Au when sited in gold(III) oxide, Au2O3, (an insulator for practical purposes). We have performed various experiments designed to detect any half-life change at the level of a few parts in 10^4 due to change in temperature, physical environment, or the Earth-Sun distance. In these experiments, we have found no significant half-life change due to any of these external factors. These results represent the most accurate demonstrations of the immutability of radioactive half-life change ever made.
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Finlay, Paul. "High-Precision Half-Life and Branching-Ratio Measurements for the Superallowed Beta+ Emitter 26Alm". Thesis, 2012. http://hdl.handle.net/10214/3510.
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High-precision half-life and branching-ratio measurements for the superallowed
beta+ emitter 26Alm were performed at the TRIUMF-ISAC radioactive ion beam facility
located in Vancouver, Canada. The branching ratio measurement was performed with
the 8pi Spectrometer, an array of 20 high-purity germanium detectors, in conjunction with SCEPTAR, a plastic scintillator array used to detect the emitted beta particles.
An upper limit of <= 12 ppm at 90% confidence level was found for the second forbidden beta + decay of 26Alm to the first 2+ state at 1809 keV in 26Mg. An inclusive upper limit of <= 15 ppm at 90% confidence level was found when considering all possible non-analogue beta +/EC decay branches of 26Alm, resulting in a superallowed branching ratio of 100.0000+0−0.0015%.
The half-life measurement was performed using a 4pi continuous-flow gas proportional counter and fast tape transport system. The resulting value for the 26Alm half-life, T1/2 = 6.34654(76) s, is consistent with, but 2.5 times more precise than, the previous world average, and represents the single most precisely measured half-life of any superallowed emitting nucleus to date.
Combining these results with world-average Q-value measurements yields a superallowed beta -decay ft value of 3037.58(60) s, the most precisely determined ft value for any superallowed emitting nucleus to date. Combined with the small, and precisely quoted, theoretical isospin-symmetry-breaking corrections for this nucleus, the corrected Ft value for 26Alm of 3073.1(12) s is also the most precisely determined for any superallowed emitter by nearly a factor of two and now rivals the precision of all the other 12 precisely measured superallowed beta decays combined. The high-precision experimental ft value for 26Alm superallowed decay reported here provides a new benchmark to refine theoretical models of isospin-symmetry-breaking effects in superallowed Fermi beta decays.
Libros sobre el tema "Changes in beta-decay half-life"
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Johnson, Nicholas J. y Judd E. Hollander. Management of cocaine poisoning. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0324.
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Cocaine is powerful central nervous system (CNS) stimulant derived from the coca plant. It affects the body via a number of mechanisms including blockade of fast sodium channels, increased catecholamine release, inhibition of catecholamine reuptake, and increased concentration of excitatory amino acid concentrations in the CNS. It is rapidly absorbed via the aerodigestive, respiratory, gastrointestinal, and genitourinary mucosa, and also may be injected. When injected intravenously or inhaled, cocaine is rapidly distributed throughout the body and CNS, with peak effects in 3–5 minutes. With nasal insufflation, absorption peaks in 20 minutes. Its half-life is approximately 1 hour. Common clinical manifestations include agitation, euphoria, tachycardia, hyperthermia, and hypertension. Chest pain is a common presenting complaint among cocaine users; 6% of these patients will have myocardial infarction. Other life-threatening sequelae include stroke, intracranial haemorrhage, seizures, dysrhythmias, and rhabdomyolysis. Clinical signs and symptoms, as well as severity of intoxication, should dictate the diagnostic evaluation and treatment of cocaine intoxicated patients. If the patient has chest pain, an ECG, chest radiograph, and measurement of cardiac biomarkers should be performed. A brief observation period may be useful in these patients. Many manifestations of cocaine intoxication, including agitation, hypertension, and chest pain, are effectively treated with benzodiazepines. Beta-blockers should be avoided in patients with suspected cocaine intoxication. Special attention should be paid to pregnant patients and those who present after ingesting packets filled with cocaine, as they may exhibit severe toxicity if these packets rupture.
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Kirshner, Jonathan y Jon Lewis, eds. When the Movies Mattered. Cornell University Press, 2019. http://dx.doi.org/10.7591/cornell/9781501736094.001.0001.
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The “New Hollywood” that emerged in the late sixties is now widely recognized as an era of remarkable filmmaking, when directors enjoyed a unique autonomy to craft ambitious, introspective movies that evinced a cinematic world of hard choices, complex interpersonal relationships, compromised heroes, and uncertain outcomes. The New Hollywood Revisited brings together a remarkable collection of authors (some of whom wrote about the New Hollywood as it unfolded), to revisit this unique era in American cinema (circa 1967-1976). It was a decade in which a number of extraordinary factors – including the end of a half-century-old censorship regime and economic and demographic changes to the American film audience – converged and created a new type of commercial film, imprinted with the social and political context of the times: the civil rights movement, the Vietnam War, the sexual revolution, women’s liberation, economic distress, urban decay, and, looming, the Shakespearean saga of the Nixon presidency. This volume offers the opportunity to look back, with nearly fifty years hindsight, at a golden age in American filmmaking.
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Ellam, Rob. 1. Identical outsides … different insides. Oxford University Press, 2016. http://dx.doi.org/10.1093/actrade/9780198723622.003.0001.
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‘Identical outsides … different insides’ describes the isotopes of hydrogen (protium, deuterium, tritium) and carbon (carbon-12, carbon-13, carbon-14). The isotopes exist due to an extra particle (neutron) or two in the element’s nucleus, which adds extra mass to the atom. Tritium and carbon-14 are both unstable and undergo radioactive decay. There are four types of radioactive decay: α, β, γ (alpha, beta, gamma), and spontaneous fission. Radioactive decay is the process whereby the nucleus of an unstable atom loses energy by emission of ionizing radiation. The rate of the radioactive decay is measured by the ‘half-life’—the time needed for half the radioactive isotopes of a substance to decay.
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Diefendorf, Barbara B. Planting the Cross. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780190887025.001.0001.
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This book examines how Catholic reformers envisioned and implemented changes to monastic life in late sixteenth- and early seventeenth-century France. Scholars of France’s Catholic Reformation have tended to focus on the movement’s later stages and, taking a top-down approach, view it from the perspective of activist clerics seeking to impose a fixed idea of religious life. This study focuses instead on the movement’s beginnings and explores the aims and tactics of proponents of reform from different but overlapping perspectives. The six case studies draw from three regions—Paris, Provence, and Languedoc. The first chapters tell the story of religious caught in the direct path of the Wars of Religion, which reduced France to near anarchy in the sixteenth century. Chapter 1 tells of the difficulty traditional women’s orders had surviving—much less reforming themselves—in Protestant-dominated Montpellier. Chapter 2 examines the rebellion of Paris’s Feuillants against both their ascetic abbot and the king during the Holy League revolt. Chapter 3 recounts the implantation of the militant Franciscans called Capuchins in the Protestant heartland, Languedoc. Chapters 4 and 5 examine the struggle to reform two old orders—the Dominicans and Trinitarians—that had fallen into decay. Chapter 6 explores conflicting interpretations of Teresa of Avila’s legacy at France’s first Carmelite convents. The book illuminates persistent debates about what constituted religious reform and how a reform’s success should be judged. It shows reform to have been lived as an ongoing process that was more diverse, experimental, and experiential than is often recognized.
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Demshuk, Andrew. Bowling for Communism. Cornell University Press, 2020. http://dx.doi.org/10.7591/cornell/9781501751660.001.0001.
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This book illuminates how civic life functioned in Leipzig, East Germany's second-largest city, on the eve of the 1989 revolution by exploring acts of “urban ingenuity” amid catastrophic urban decay. The book profiles the creative activism of local communist officials who, with the help of scores of volunteers, constructed a palatial bowling alley without Berlin's knowledge or approval. In a city mired in disrepair, civic pride overcame resentment against a regime loathed for corruption, Stasi spies, and the Berlin Wall. Reconstructing such episodes through interviews and obscure archival materials, the book shows how the public sphere functioned in Leipzig before the fall of communism. Hardly detached or inept, local officials worked around centralized failings to build a more humane city. And hardly disengaged, residents turned to black-market construction to patch up their surroundings. Because such “urban ingenuity” was premised on weakness in the centralized regime, the dystopian cityscape evolved from being merely a quotidian grievance to the backdrop for revolution. If, by their actions, officials were demonstrating that the regime was irrelevant, and if, in their own experiences, locals only attained basic repairs outside official channels, why should anyone have mourned the system when it was overthrown?
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Bhopal, Raj S. Epidemic of Cardiovascular Disease and Diabetes. Oxford University Press, 2019. http://dx.doi.org/10.1093/med/9780198833246.001.0001.
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Coronary heart disease (CHD) and stroke, collectively cardiovascular disease (CVD), are caused by narrowing and blockage of the arteries supplying the heart and brain, respectively. In type 2 diabetes (DM2) insulin is insufficient to maintain normal blood glucose. South Asians have high susceptibility to these diseases. Drawing upon the scientific literature and discussions with 22 internationally recognized scholars, this book focuses on causal explanations and their implications for prevention and research. Genetically based hypotheses are considered together with the developmental origins of health and disease (DOHAD) family of hypotheses. The book then considers how CHD, stroke, and DM2 are closely linked to rising affluence and the accompanying changes in life-expectancy and lifestyles. The established causal factors are shown to be insufficient, though necessary, parts of a convincing explanation for the excess of DM2 and CVD in South Asians. In identifying new explanations, this book emphasizes glycation of tissues, possibly leading to arterial stiffness and microcirculatory damage. In addition to endothelial pathways to atherosclerosis an external (adventitial) one is proposed, i.e. microcirculatory damage to the network of arterioles that nourish the coronary arteries. In addition to the ectopic fat in their liver and pancreas as the cause of beta cell dysfunction leading to DM2, additional ideas are proposed, i.e. microcirculatory damage. The high risk of CVD and DM2 in urbanizing South Asians is not inevitable, innate or genetic, or acquired in early life and programmed in a fixed way. Rather, exposure to risk factors in childhood, adolescence, and most particularly in adulthood is the key. The challenge to produce focused, low cost, effective actions, underpinned by clear, simple, and accurate explanations of the causes of the phenomenon is addressed.
Capítulos de libros sobre el tema "Changes in beta-decay half-life"
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Nunberg, Sarah, Sarah Sutton y Matthew Eckelman. "Planning a Life Cycle Analysis Library and Beta Tool for Sustainable Cultural Heritage Preservation and Exhibition Practices". En Climate Change Management, 531–43. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-98294-6_32.
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LEVINE, C. A., A. GHIORSO y G. T. SEABORG. "Half-Life for Double Beta-Decay". En World Scientific Series in 20th Century Chemistry, 457. WORLD SCIENTIFIC, 1994. http://dx.doi.org/10.1142/9789812795953_0081.
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"The Portuguese Constitution of 1976: Half-life and decay". En Engineering Constitutional Change, 283–308. Routledge, 2012. http://dx.doi.org/10.4324/9780203094990-21.
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Schweitzer, George K. y Lester L. Pesterfield. "The Scandium Group". En The Aqueous Chemistry of the Elements. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780195393354.003.0014.
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The members of the Sc Group are Sc scandium, Y yttrium, La lanthanum, Ce cerium, Pr praseodymium, Nd neodymium, Pm promethium, Sm samarium, Eu europium, Gd gadolinium, Tb terbium, Dy dysprosium, Ho holmium, Er erbium, Tm thulium, Yb ytterbium, Lu lutetium, and Ac actinium. All these elements resemble each other greatly, especially in the series La–Lu (called the lanthanoids). Their slight differences may be assigned largely to size similarities, but a few oxidation state changes give rise to marked differences. The predominant oxidation state is III, but the IV state for Ce, and the II state for Eu are also important in their aqueous chemistries. The electron structures of these elements along with some other of their pertinent properties are shown in Table 12.1. Note the progression in the sizes of M+3 rising from Sc to Ac, but decreasing from La to Lu. This behavior causes Y+3 to fall in between Dy+3 and Ho+3, which results in yttrium’s chemistry usually resembling the latter lanthanoids. For this reason, Y will be treated as a lanthanoid in succeeding sections. The successive filling of the 4f electron level from La through Lu should also be noted, as well as the interesting 5d occupancy for Gd. The richest ore of Sc is the rare mineral thorveitite Sc2Si2O7, but it also occurs in very small quantities in some lanthanoid, uranium, and tungsten ores. Yttrium and the lanthanoids (abbreviated Ln), except for Pm, occur in monazite LnPO4 (mostly light lanthanoids), bastnaesite LnCO3F (mostly light lanthanoids), xenotime LnPO4 (mostly heavy lanthanoids), loparite (mostly light lanthanoids), and lateritic clays (some with mostly light lanthanoids, others with mostly heavy lanthanoids). All isotopes of Pm are radioactive and it does not occur with the lanthanoids. Exceedingly small amounts are present in uranium ores where it has been produced by the spontaneous fission of U-238. Its major source is artificial production, the longest lived isotope being Pm-145 (half life of 17.7 years). Ac is also without a stable isotope, the radioactive element resulting from the decay of naturally occurring Th and U. The longest lived Ac species is Ac-227 which has a half life of 21.77 years.
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Hocking, Judith y Anthony Maeder. "Motivational Embodied Conversational Agent for Brain Injury Rehabilitation". En Studies in Health Technology and Informatics. IOS Press, 2021. http://dx.doi.org/10.3233/shti210026.
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The design and development of a motivational embodied conversational agent for brain injury rehabilitation is discussed. Results for initial prototype design and implementation, and alpha and beta testing phases are presented. Key aspects identified during development included supporting user engagement via personalization and choice-making; integrating behaviour change principles into dialogues; addressing clinical needs of cognitive fatigue and memory loss within conversation structure; and optimizing feasibility of use in a real-life clinical setting.
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Townsend, Peter. "Decay of Information and Data Loss". En The Evolution of Music through Culture and Science, 135–50. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198848400.003.0009.
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Our impression is that advances in science and technology are improving music and all the recordings etc. will mean that we have long-term access to ever more music. In the very short term this may be true but historically the pattern is the reverse, and faster data production of words or images actually result in a shorter lifetime. This pattern is seen from carvings on stone (with little content but long-term survival) to computer generated pop music with vast distribution and a very short life expectancy before it is out of fashion. Languages change meaning or die, and so do musical fashions. This chapter explores how this inherent data loss applies to music.
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Travin, Sergey Olegovich y Oleg Borisovich Gromov. "Contribution of the “Great Carbon Tracker” in the Dilution of Atmospheric Radiocarbon Emissions". En Handbook of Research on Emerging Developments and Environmental Impacts of Ecological Chemistry, 137–47. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1241-8.ch006.
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The general model of global carbon circulation (in particular 14C) have been known for half a century and includes both natural and anthropogenic sources and sinks. The main problem was the lack of information about rates of migration from one form to another. The authors made fitting of model data concerning both 12C and 14C dynamics in atmosphere and in sea water. The 70-times discrepancy between generation and decay rates for radiocarbon was explained. The main channel of 14C disappearance is not decay but dissolution in sea waters. By this reason, they deny the Suesse hypothesis because atmospheric carbon dioxide is diluted not by 14C-free substance (after burning of fossil fuels) but from the source of oceans. Multiple numeric experiments modeling 14C pulse or permanent input to the environment had demonstrated the exclusive stability of natural system. It obeys homeostatic principle and resists any attempts to shift steady state concentration. So, all speculations about extraordinary threat from technogenic 14C from nuclear industry do not have any scientific base.
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Rabbitt, Patrick. "Inner-city decay? Age changes in structure and process in recall of familiar topographical information". En Everyday Cognition in Adulthood and Late Life, 284–99. Cambridge University Press, 1989. http://dx.doi.org/10.1017/cbo9780511759390.018.
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Di Blasi, Elena, Alessandro Arangio y Nunziata Messina. "Rehabilitation and Reuse of Rural Farms in a Region of Inner Sicily". En Handbook of Research on Agricultural Policy, Rural Development, and Entrepreneurship in Contemporary Economies, 152–66. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-5225-9837-4.ch008.
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The rural landscape of inner Sicily has peculiar characteristics, deeply different from the ones of coastal Sicily, marked by the presence of citrus orchards, vineyards, and greenhouses. Inner Sicily was traditionally dominated by cereal latifundia. With low level cities (the main ones are all concentrated along the coasts), in the past a central role in the agrarian economy of this inland region was played by rural farms, called “masserie”. In the second half of the 20th century, the national agrarian reform opened the doors to profound changes. The inland areas were suddenly abandoned, while many coastal centres reported a significant population growth. The rural farms of inner Sicily were abandoned and bound to decay. In the last years, some of these “masserie” have been restored. They are of course an important resource that has to be exploited to generate richness. The chapter presents the experience of the territory of Aidone, rich in farms and resources.
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Nette, Andrew. "Towards Rollerball". En Rollerball, 21–36. Liverpool University Press, 2018. http://dx.doi.org/10.3828/liverpool/9781911325666.003.0002.
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This chapter discusses the origins of Rollerball (1975) in the context of science-fiction cinema in the late 1960s and the first half of the 1970s, when the genre began a move to the centre of the commercial film business. It also took a distinctly dark turn as the impact of the Vietnam War, economic recession, the OPEC oil crisis, debates about overpopulation, environmental destruction, and, in the US, urban decay, and the political corruption revealed by the Watergate scandal worked their way into public consciousness. These concerns were all reflected in 1970s science fiction, and particularly percolated up in the decade's dystopian offerings. They also gave rise to the paranoia cycle of Hollywood thrillers that appeared in the late 1960s and early 1970s, in the context of which aspects of Rollerball can be viewed. The chapter then outlines some of the broader cultural debates William Harrison and Norman Jewison found themselves part of during the same period, principally concerns over increasing violence in professional American sport and society more generally, technological change, and growing corporate power.
Actas de conferencias sobre el tema "Changes in beta-decay half-life"
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Stoker, Joshua, Paul Mantica, Daniel Bazin, Ana Delia Becerril Reyes, Jill S. Berryman, Heather L. Crawford, Alfredo Estrade et al. "Beta-Decay Half Life of 84Mo". En 10th Symposium on Nuclei in the Cosmos. Trieste, Italy: Sissa Medialab, 2009. http://dx.doi.org/10.22323/1.053.0179.
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Barabash, A. S., Osvaldo Civitarese, Ivan Stekl y Jouni Suhonen. "Average and recommended half-life values for two neutrino double beta decay: upgrade-09". En WORKSHOP ON CIRCULATION OF DOUBLE-BETA-DECAY MATRIX. AIP, 2009. http://dx.doi.org/10.1063/1.3266106.
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Barabash, A. S. "Average and recommended half-life values for two-neutrino double beta decay: Upgrade-2019". En WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19). AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5130963.
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Barabash, A. S. "Average and recommended half-life values for two neutrino double beta decay: Upgrade-2013". En THE 2013 UKM FST POSTGRADUATE COLLOQUIUM: Proceedings of the Universiti Kebangsaan Malaysia, Faculty of Science and Technology 2013 Postgraduate Colloquium. AIP Publishing LLC, 2013. http://dx.doi.org/10.1063/1.4856538.
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Groma, G. I., Gabor Szabo y L. Keszthelyi. "Conformation changes in bacteriorhodopsin photocycle studied by pump and probe tryptophan fluorescence decay". En Laser Spectroscopy of Biomolecules: 4th International Conference on Laser Applications in Life Sciences, editado por Jouko E. Korppi-Tommola. SPIE, 1993. http://dx.doi.org/10.1117/12.146116.
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Kim, Seong Hoon, Kyoungwoo Seo, Dae-young Chi y Juhyeon Yoon. "Generation of Pressure Distribution Inside a Decay Tank in a Research Reactor Using CFD". En ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-63934.
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The Primary Cooling System (PCS) of a research reactor circulates coolant to remove the heat produced in the fuel or irradiation device. The core outlet coolant contains many kinds of radionuclides because it passes the reactor core [1]. As N-16 among them emits a very hard gamma ray, it not only causes radiation damage to some components but also requires very heavy shielding of the primary cooling loop. Since its half-life is 7.13s, its level can be effectively lowered by installing a decay tank including an internal structure to provide a transit time [2]. To ensure that the N-16 activity decreases enough before the coolant leaves the heavily shielded decay tank room, perforated plates are installed inside the decay tank. The perforated plates are designed to disturb and delay the PCS flow. Normally, when a flow from a relative narrow inlet nozzle goes out to an enlarged tank, it becomes a complex turbulent flow inside the tank. In addition, the PCS flow is frequently changed from zero to a normal flow rate owing to the research reactor characteristics. Thus, the integrity of the perforated plate shall be verified with the pump operation and shutdown condition.
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Lattanzio, Susan, Linda Newnes, Marcelle McManus y Derrick Dunkley. "Life Cycle Decision Support Tools: The Use of Quality Management Techniques in Combating Decision Tool “Performance Decay”". En ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-59888.
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Ensuring that global infrastructure keeps pace with the demands of economic growth and human wellbeing is anticipated to result in spend of US$57 trillion (2013–30). Specific to the UK power sector, redesigning the electrical transmission network to support decarbonisation of the economy will result in an estimated spend in the region of US$50 billion (2010–20). The challenge within the infrastructure sector is in ensuring that investment productivity is maximized and the appropriate assets are built. One approach being used are decision support tools (DSTs) aimed at assisting the optimum asset choice, by considering a range of costs across the life of the asset. However, there is a gap in ensuring the sustainability of these tools: that is, ensuring that after adoption they continue to offer the same value. The research presented in this paper considers ‘performance decay’ of DSTs and proposes an approach to ensure they remain ‘fit for purpose’. Our research proposes that adopting a quality management system approach will combat performance decay, and move current DSTs from ‘static’ to ‘live’ and evolving states. Within this paper a review of literature is provided. Scenarios are used to explore possible changes in performance, and an industry exemplar used to demonstrate the plausibility of performance decay. An approach to address performance decay by embedding quality management systems techniques is then introduced.
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Futrzynski, Romain y Gunilla Efraimsson. "Effect of a SDBD on the Drag of a Half-Submerged Cylinder in Crossflow". En ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21958.
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In this paper the effect of a SDBD-type plasma actuator on the flow over a half-submerged cylinder is investigated numerically. The actuator is modeled via a body force, which is steady in time and where an exponential decay in space is assumed. First, the parameters in the numerical actuator model are determined for the case of no flow by optimization relative to experimental data. Thereafter, numerical solutions for the case with flow are studied numerically with and without actuation. A grid study is performed to check that the flow structures are resolved in both space and time. The effect of the actuator is examined. Although no significant change is observed when using the optimized parameters, using a stronger body force yields a reduction in drag of the order of 5%.
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John, J. y M. T. Schobeiri. "Development of Two-Dimensional Turbulent Wakes in a Curved Channel at Positive Streamwise Pressure Gradient". En ASME 1994 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/94-gt-384.
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The development of turbomachinery wake flows are greatly influenced by streamline curvature and streamwise pressure gradient. This paper is a part of a comprehensive experimental and theoretical study on the development of the steady and the periodic unsteady turbulent wakes in curved channels at different streamwise pressure gradients. The experimental investigation of the two-dimensional wake behind a stationary circular cylinder in a curved channel at positive streamwise pressure gradient is reported in this paper. Measurements of mean velocity and Reynolds stress components are carried out using a X-hot-film probe. The measured quantities obtained in probe coordinates are transformed to a curvilinear coordinate system along the wake center line and are presented in similarity coordinates. The results indicates strong asymmetry in velocity and Reynolds stress components. The Reynolds stress components have higher values at the inner half of the wake than at the outer half of the wake. However, the mean velocity defect profiles in similarity coordinates is almost symmetric and follows the same Gaussian function for the straight wake data. A comparison with the wake development in a curved channel at zero streamwise pressure gradient suggests that the decay rate of velocity defect is slower and the growth of wake width is faster in the case of positive streamwise pressure gradient.
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Moran, Joaquin E. y David S. Weaver. "Damping Measurements in Tube Bundles Subjected to Two-Phase Cross Flow". En ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93431.
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An experimental study was conducted to investigate two-phase damping in tube arrays. The objective was to compare different measurement methodologies in order to obtain a more reliable damping estimate. This will allow for improved guidelines related to failures due to fluidelastic instability in tube bundles. The methods compared were the traditionally used half-power bandwidth, the logarithmic decrement and an exponential fitting to the tube decay response. The working fluid used was Refrigerant 11 (Freon), which better models the real steam-water problem, as it allows for phase change. The void fraction was measured using a gamma densitometer, introducing an improvement over the traditional Homogeneous Equilibrium Model (HEM) in terms of velocity and density predictions. The results obtained by using the half-power bandwidth method agree with data previously reported for two-phase flow. The experiments showed that the half-power bandwidth produces higher damping values than the other two, but only up to a certain void fraction. After that point, the results obtained from the three methods are very similar. The exponential fitting proved to be more consistent than the logarithmic decrement, and it is not as sensitive as the half-power bandwidth to the frequency shifting caused by the change in added mass around the tube. By plotting the damping ratio as a function of void fraction, pitch mass flux and flow regime, we were able to verify that damping is more dependent on void fraction and flow regime than on mass flux.
Informes sobre el tema "Changes in beta-decay half-life"
1
Pritychenko, B. On Double-Beta Decay Half-Life Time Systematics. Office of Scientific and Technical Information (OSTI), abril de 2010. http://dx.doi.org/10.2172/1013470.
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Pritychenko, B. Comment on ?Precise half-life values for two-neutrino double beta decay? Office of Scientific and Technical Information (OSTI), mayo de 2010. http://dx.doi.org/10.2172/981818.
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Surdoval, Wayne A., David A. Berry, Travis Shultz y Antonio Ferreira. Two Physically Different Neutron Beta-Decay Half-Life Calculations are in Exact Agreement with the NIST Beam Experiment. Office of Scientific and Technical Information (OSTI), diciembre de 2019. http://dx.doi.org/10.2172/1576789.
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