Direct determination of photodisintegration cross sections and the p-process

Photon-induced reactions play a key role in the nucleosynthesis of heavy neutron-deficient nuclei, the so-called p-nuclei. In this paper we review the present status of experiments on photon-induced reactions at energies of astrophysical importance and their relevance to p-process modeling.Comment: Nucl. Phys. A, in pres

Induction of inflorescence by CCC application on primary shoots of grapevines

Repeated CCC application at 500 ppm under the conditions of extended lang days and lower temperature of about 20 °C specifically induced inflorescences in place of tendrils on extending primary shoots of young graftings or cuttings of Muscat of Alexandria grapes.Inflorescence formation in the winter buds was much greater at 30 °C than at 20 °C along the whole shoot. CCC application increased inflorescence formation remarkably at either temperature, the effect being more pronounced at 20 °C.Die Induktion von Infloreszenzen durch Behandlung der Haupttriebe von Reben mit CCCJunge Pfropfreben oder Stecklinge der Sorte Muskat von Alexandria, deren Haupttriebe sich im Streekungswachstum befanden, wurden wiederholt mit 500 ppm CCC behandelt. Hierdurch wurden im ausgedehnten Langtag und in einem niedrigeren Temperaturbereich (ca. 20 °C) anstelle von Ranken speziell Infloreszenzen induziert. Längs des ganzen Triebes wurden in den Winterknospen bei 30 °C (ohne CCC-Behandlung) viel mehr Infloreszenzen angelegt als bei 20 °C. Durch CCC wurde die Infloreszenzbildung in beiden Temperaturbereichen beträchtlich gefördert, wobei für 20 °C eine auffälligere Wirkung festzustellen war

Effect of abscisic acid and defoliation on anthocyanin accumulation in Kyoho grapes (Vitis vinifera L. x V. labruscana BAILEY)

In Kyoho grapes, ABA treatment at 1000 ppm in the beginning of ripening enhanced anthocyanin accumulation in the skin without any effect on the contents of soluble solids and titratable acids in the juice.By defoliation at veraison, anthocyanin synthesis was completely inhibited, and the soluble solids content in the juice and sugar levels in the skin became much less than those of the control. Furthermore, endogenous ABA levels in the skin and flesh did not increase throughout ripening period.On such defoliated vines, the berries recovered anthocyanin accumulation by ABA application.From these results, it will be assumed that ABA which accumulates in the skin is one of the main factors involved in the anthocyanin synthesis.Der Einfluß von Abscisinsäure und Entblätterung auf die Anthocyanakkumulation in Trauben der Rebsorte Kyoho (Vitis vinifera L. x V. labruscana BAILEY)Wurden Kyoho-Trauben zu Beginn der Beerenreife mit 1 000 ppm ABS behandelt, so war in den Beerenhäuten verstärkt Anthocyan angereichert, ohne daß Mostgewicht und tritierbare Säure des Beerensaftes irgendwie beeinflußt waren. Durch Entblätterung der Reben zur Zeit des Weichwerdens der Beeren wurde die Anthocyansynthese vollkommen unterdrückt, und das Mostgewicht des Beerensaftes wie auch die Zuckerkonzentration der Beerenhaut waren gegenüber der Kontrolle bedeutend verringert. Ferner nahm die Konzentration der endogenen ABS in Beerenhaut und -fleisch während der ganzen Reifeperiode nicht zu.Bei den entblätterten Reben setzte nach der Applikation von ABS die Anthocyanakkumulation in den Beeren wieder ein.Aus den vorliegenden Ergebnissen wird gefolgert, daß die Anreicherung von ABS in der Beerenhaut einer der Hauptfaktoren ist, die an der Anthocyansynthese beteiligt sind

Quasicontinuum γ\gamma-decay of 91,92^{91,92}Zr: benchmarking indirect (n,γn,\gamma) cross section measurements for the ss-process

Nuclear level densities (NLDs) and $\gamma$-ray strength functions ($\gamma$SFs) have been extracted from particle-$\gamma$ coincidences of the $^{92}$Zr($p,p' \gamma$)$^{92}$Zr and $^{92}$Zr($p,d \gamma$)$^{91}$Zr reactions using the Oslo method. The new $^{91,92}$Zr $\gamma$SF data, combined with photonuclear cross sections, cover the whole energy range from $E_{\gamma} \approx 1.5$~MeV up to the giant dipole resonance at $E_{\gamma} \approx 17$~MeV. The wide-range $\gamma$SF data display structures at $E_{\gamma} \approx 9.5$~MeV, compatible with a superposition of the spin-flip $M1$ resonance and a pygmy $E1$ resonance. Furthermore, the $\gamma$SF shows a minimum at $E_{\gamma} \approx 2-3$~MeV and an increase at lower $\gamma$-ray energies. The experimentally constrained NLDs and $\gamma$SFs are shown to reproduce known ($n, \gamma$) and Maxwellian-averaged cross sections for $^{91,92}$Zr using the {\sf TALYS} reaction code, thus serving as a benchmark for this indirect method of estimating ($n, \gamma$) cross sections for Zr isotopes.Comment: 10 pages and 9 figure

Formation of submicron-sized silica patterns on flexible polymer substrates based on vacuum ultraviolet photooxidation

Formation of precise and high-resolution silica micropatterns on polymer substrates is of importance in surface structuring for flexible device fabrication of optics, microelectronic, and biotechnology. To achieve that, substrates modified with affinity-patterns serve as a strategy for site-selective deposition. In the present paper, vacuum ultraviolet (VUV) treatment is utilized to achieve spatially-controlled surface functionalization on a cyclo-olefin polymer (COP) substrate. An organosilane, 2, 4, 6, 8-tetramethylcyclotetrasiloxane (TMCTS), preferentially deposits on the functionalized regions. Well-defined patterns of TMCTS are formed with a minimum feature of ∼500 nm. The secondary VUV/(O)-treatment converts TMCTS into SiOx, meanwhile etches the bare COP surface, forming patterned SiOx/COP microstructures with an average height of ∼150 nm. The resulting SiOx patterns retain a good copy of TMCTS patterns, which are also consistent with the patterns of photomask used in polymer affinity-patterning. The high quality SiOx patterns are of interests in microdevice fabrication, and the hydrophilicity contrast and adjustable heights reveal their potential application as a “stamp” for microcontact printing (μCP) techniques

Pygmy dipole strength close to particle-separation energies - the case of the Mo isotopes

The distribution of electromagnetic dipole strength in 92, 98, 100 Mo has been investigated by photon scattering using bremsstrahlung from the new ELBE facility. The experimental data for well separated nuclear resonances indicate a transition from a regular to a chaotic behaviour above 4 MeV of excitation energy. As the strength distributions follow a Porter-Thomas distribution much of the dipole strength is found in weak and in unresolved resonances appearing as fluctuating cross section. An analysis of this quasi-continuum - here applied to nuclear resonance fluorescence in a novel way - delivers dipole strength functions, which are combining smoothly to those obtained from (g,n)-data. Enhancements at 6.5 MeV and at ~9 MeV are linked to the pygmy dipole resonances postulated to occur in heavy nuclei.Comment: 6 pages, 5 figures, proceedings Nuclear Physics in Astrophysics II, May 16-20, Debrecen, Hungary. The original publication is available at www.eurphysj.or

Photo-disintegration cross section measurements on 186^{186}W, 187^{187}Re and 188^{188}Os: Implications for the Re-Os cosmochronology

Cross sections of the $^{186}$W, $^{187}$Re, $^{188}$Os($\gamma,n$) reactions were measured using quasi-monochromatic photon beams from laser Compton scattering (LCS) with average energies from 7.3 to 10.9 MeV. The results are compared with the predictions of Hauser-Feshbach statistical calculations using four different sets of input parameters. In addition, the inverse neutron capture cross sections were evaluated by constraining the model parameters, especially the $E1$ strength function, on the basis of the experimental data. The present experiment helps to further constrain the correction factor $F_{\sigma}$ for the neutron capture on the 9.75 keV state in $^{187}$Os. Implications of $F_{\sigma}$ to the Re-Os cosmochronology are discussed with a focus on the uncertainty in the estimate of the age of the Galaxy.Comment: 11 page