Neutrino and anti-neutrino energy loss rates due to iron isotopes suitable for core-collapse simulations

Accurate estimate of neutrino energy loss rates are needed for the study of the late stages of the stellar evolution, in particular for cooling of neutron stars and white dwarfs. The energy spectra of neutrinos and antineutrinos arriving at the Earth can also provide useful information on the primary neutrino fluxes as well as neutrino mixing scenario (it is to be noted that these supernova neutrinos are emitted after the supernova explosion which is a much later stage of stellar evolution than that considered in this paper). Recently an improved microscopic calculation of weak-interaction mediated rates for iron isotopes was introduced using the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. Here I present for the first time the fine-grid calculation of the neutrino and anti-neutrino energy loss rates due to $^{54,55,56}$Fe in stellar matter. In the core of massive stars isotopes of iron, $^{54,55,56}$Fe, are considered to be key players in decreasing the electron-to-baryon ratio ($Y_{e}$) mainly via electron capture on these nuclide. Core-collapse simulators may find this calculation suitable for interpolation purposes and for necessary incorporation in the stellar evolution codes. The calculated cooling rates are also compared with previous calculations.Comment: 12 pages, 3 figures and 1 table. arXiv admin note: text overlap with arXiv:1108.4569, arXiv:1203.4675, arXiv:1203.434

Inside the news: challenges and aspirations of women journalists in Asia and the Pacific

There are more women media professionals than ever in many countries across Asia-Pacific, but they still represent only three out of 10 newsroom staff, often earn less than their male counterparts and are subject to sexual harassment, while struggling to reach decision-making positions. These are some of the findings in Inside the News: Challenges and Aspirations of Women Journalists in Asia and the Pacific. The report highlights how issues of gender impact the lives and work of journalists in the region, with case studies drawn from the personal accounts of media professionals in Cambodia, India, Malaysia, Nepal, Pakistan, Sri Lanka and Vanuatu. Nearly 700 journalists from the target countries participated in the study, which drew on surveys of journalists, focus group interviews with representatives of media outlets, as well as interviews with media organisation and national professional associations. Key findings include: - Jobs women in the media do: Reporters (30%), Feature writers (16%), Editors (11%), Sub/Copy Editors (10%), Columnists (8%), News Anchors (8%), Producers (7%), Photographers (5%), Design/Layout (2%), Media support (2%), Camera/Sound (1%) - Gender pay gap in Asia-Pacific Media: US$69 (Average monthly salary US$437 for women, US$506 for men). - How can we foster gender equality in media? Women journalists say ‘Having more women in decision making roles’ (25%) and ‘Affirmative employment strategies’ (20%). Male journalists say ’Having more women in the media at every level’ (28%) and ‘More family friendly work conditions’ (22%). - Women at work in the media: 3 out of 10 news staff are women. 23% of women are middle editorial decision makers; 20% are senior editorial decision makers; 18% are media executives. - 18% of women journalists have experienced sexual harassment at work, while 34% of them have witnessed it.   - Do Women have enough visibility in unions? 48% of the respondents say ‘No’, 23% say ‘Yes’, 25% ‘don’t know’

Unique first-forbidden β\beta-decay rates for neutron-rich nickel isotopes in stellar environment

In astrophysical environments, allowed Gamow-Teller (GT) transitions are important, particularly for $\beta$-decay rates in presupernova evolution of massive stars, since they contribute to the fine-tuning of the lepton-to-baryon content of the stellar matter prior to and during the collapse of a heavy star. In environments where GT transitions are unfavored, first-forbidden transitions become important especially in medium heavy and heavy nuclei. Particularly in case of neutron-rich nuclei, first-forbidden transitions are favored primarily due to the phase-space amplification for these transitions. In this work the total $\beta$-decay half-lives and the unique first-forbidden(U1F) $\beta$-decay rates for a number of neutron-rich nickel isotopes, $^{72-78}$Ni, are calculated using the proton-neutron quasi-particle random phase approximation (pn-QRPA) theory in stellar environment for the first time. For the calculation of the $\beta$-decay half-lives both allowed and unique first-forbidden transitions were considered. Comparison of the total half-lives is made with measurements and other theoretical calculations where it was found that the pn-QRPA results are in better agreement with experiments and at the same time are suggestive of inclusion of rank 0 and rank 1 operators in first-forbidden rates for still better results.Comment: (16 pages, 10 figures, 2 tables

Reconsidering extra time-like dimensions

In this study we reconsider the phenomenological problems related to tachyonic modes in the context of extra time-like dimensions. First we reconsider a lower bound on the size of extra time-like dimensions. Next we discuss the issues of spontaneous decay of stable fermions through tachyonic decays and disappearance of fermions due to tachyonic contributions to their self-energies. We find that the tachyonic modes due to extra time-like dimensions are less problematic than the tachyonic modes in the usual 4-dimensional setting because the most troublesome Feynman diagrams are forbidden once the conservation of momentum in the extra time-like dimensions is imposed.Comment: The version to appear in EPJ

A Unified Model for inelastic e-N and nu-N cross sections at all Q2

We present results using a new scaling variable, xi_w in modeling electron- and neutrino-nucleon scattering cross sections with effective leading order PDFs.Our model uses all inelastic charged lepton F_2 data (SLAC/BCDMS/NMC/HERA), and photoproduction data on hydrogen and deuterium. We find that our model describes all inelastic scattering charged lepton data, the average of JLAB resonance data, and neutrino data at all Q2. This model is currently used by current neutrino oscillation experiments in the few GeV region.Comment: 4 pages, 4 figures, presented at 13th International Workshop on Deep Inelastic Scattering (DIS 05), Madison, Wisconsin, 27 Apr - 1 May 200