15 research outputs found

    Nuclear astrophysics with radioactive ions at FAIR

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    The nucleosynthesis of elements beyond iron is dominated by neutron captures in the s and r processes. However, 32 stable, proton-rich isotopes cannot be formed during those processes, because they are shielded from the s-process flow and r-process, β-decay chains. These nuclei are attributed to the p and rp process. For all those processes, current research in nuclear astrophysics addresses the need for more precise reaction data involving radioactive isotopes. Depending on the particular reaction, direct or inverse kinematics, forward or time-reversed direction are investigated to determine or at least to constrain the desired reaction cross sections. The Facility for Antiproton and Ion Research (FAIR) will offer unique, unprecedented opportunities to investigate many of the important reactions. The high yield of radioactive isotopes, even far away from the valley of stability, allows the investigation of isotopes involved in processes as exotic as the r or rp processes

    Improved HER activity of Ni and stainless steel electrodes activated by NiCoMo ionic activator - A combined DFT and experimental study

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    In this paper we discussed various factors contributing to the improvement of hydrogen evolution reaction (HER) activity of Ni and stainless steel electrodes activated by in situ addition of NiCoMo activators, using a combination of experimental techniques and DFT calculations. By comparing energy consumption of stainless steel (SS) electrodes in a lab scale alkaline electrolyzer with and without ionic activation, we obtained reduction of energy consumption by 21% at industrial conditions (high current density and temperature). We recorded U-I curves for activated and non-activated stainless steel electrodes in the current density range from 40 to 500 mA cm(2) and in the temperature range 298-343 K, and the obtained results were used in an electrochemical model of the laboratory alkaline electrolyzer. Increase of the electrode surface upon addition of ionic activators was confirmed by profilometric measurements and SEM analysis. Finally, we applied density functional theory (DFT) to discuss partial roles of applied ionic activators (Ni, Co and Mo) in the modification and improvement of the intrinsic properties of the cathode towards the HER in alkaline medium. From the combination of profilometric, SEM and DFT results, we conclude that the main factor contributing to the improvement of HER activity of Ni electrodes upon NiCoMo activation is the increase of electrode surface area

    Prognostic factors for recurrence and survival in uncommon variants of vulvar cancer

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    Purpose: To analyze the prognostic factors of recurrence and overall survival in rare histotypes of vulvar cancer. Methods: An international multicenter retrospective study including patients diagnosed with vulvar cancer was performed. One hundred centers participated in the study and 2453 vulvar cancer cases were enrolled from January 2001 until December 2005. After exclusion of squamous vulvar cancer, Paget´s disease and vulvar melanoma 112 tumors were analyzed for the present study. Results: The mean age at diagnosis was 64.9 ± 17.2 years. 99 (88.4%) patients had a single lesion, in 25 (22.3%) cases the vulvar tumor involved the midline, and only 13 (11.5%) patients had clinically positive inguinal lymph nodes. The mean size of the lesion was 33.8 ± 33.9 mm. Regarding the surgical treatment, 2 (1.8%) patients underwent skinning vulvectomy, 63 (56.3%) local excision, 41 (36.6%) vulvectomy, 3 (2.7%) exenteration and 3 (2.7%) did not receive any surgical treatment. The mean free surgical margin was 8.2 ± 9 mm and 7 (6.2%) patients presented positive inguinal nodes. Radiotherapy was administered in 22 (19.6%) patients and it was performed postoperatively in all cases; 14 (12.5%) patients received adjuvant chemotherapy. The mean overall follow-up time was 44.1 ± 35.7 months. The risk factors associated with overall survival were chemotherapy and radiotherapy, tumor size and stromal invasion (p < 0.05). The only independent factor significantly associated with global recurrence and absence of metastasis was radiotherapy (p = 0.02 and p = 0.002, respectively). Conclusion: Postoperative radiotherapy seems to be the only independent factor associated with recurrence and overall survival in uncommon types of vulvar cancer. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature

    Subterranean atmospheres may act as daily methane sinks

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    In recent years, methane (CH4) has received increasing scientific attention because it is the most abundant non-CO2 atmospheric greenhouse gas (GHG) and controls numerous chemical reactions in the troposphere and stratosphere. However, there is much that is unknown about CH4 sources and sinks and their evolution over time. Here we show that near-surface cavities in the uppermost vadose zone are now actively removing atmospheric CH4. Through seasonal geochemical tracing of air in the atmosphere, soil and underground at diverse geographic and climatic locations in Spain, our results show that complete consumption of CH4 is favoured in the subsurface atmosphere under near vapour-saturation conditions and without significant intervention of methanotrophic bacteria. Overall, our results indicate that subterranean atmospheres may be acting as sinks for atmospheric CH4 on a daily scale. However, this terrestrial sink has not yet been considered in CH4 budget balances
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