Relativistic effects in the solar EOS

We study the sensitivity of the sound speed to relativistic corrections of the equation of state (EOS) in the standard solar model by means of a helioseismic forward analysis. We use the latest GOLF/SOHO data for $\ell = 0,1,2,3$ modes to confirm that the inclusion of the relativistic corrections to the adiabatic exponent $\Gamma_1$ computed from both OPAL and MHD EOS leads to a more reliable theoretical modelling of the innermost layers of the Sun.Comment: 3 pages, 3 figures, aa.cls, to appear on Astronomy and Astrophysic

Seismology of Procyon A: determination of mode frequencies, amplitudes, lifetimes, and granulation noise

The F5 IV-V star Procyon A (aCMi) was observed in January 2001 by means of the high resolution spectrograph SARG operating with the TNG 3.5m Italian telescope (Telescopio Nazionale Galileo) at Canary Islands, exploiting the iodine cell technique. The time-series of about 950 spectra carried out during 6 observation nights and a preliminary data analysis were presented in Claudi et al. 2005. These measurements showed a significant excess of power between 0.5 and 1.5 mHz, with ~ 1 m/s peak amplitude. Here we present a more detailed analysis of the time-series, based on both radial velocity and line equivalent width analyses. From the power spectrum we found a typical p-mode frequency comb-like structure, identified with a good margin of certainty 11 frequencies in the interval 0.5-1400 mHz of modes with l=0,1,2 and 7< n < 22, and determined large and small frequency separations, Dn = 55.90 \pm 0.08 muHz and dnu_02=7.1 \pm 1.3 muHz, respectively. The mean amplitude per mode (l=0,1) at peak power results to be 0.45 \pm 0.07 m/s, twice larger than the solar one, and the mode lifetime 2 \pm 0.4 d, that indicates a non-coherent, stochastic source of mode excitation. Line equivalent width measurements do not show a significant excess of power in the examined spectral region but allowed us to infer an upper limit to the granulation noise.Comment: 10 pages, 15 figures, 4 tables. Accepted for publication in A&

Precision limits of the twin-beam multiband URSULA

URSULA is a multiband astronomical photoelectric photometer which minimizes errors introduced by the presence of the atmosphere. It operates with two identical channels, one for the star to be measured and the other for a reference star. After a technical description of the present version of the apparatus, some measurements of stellar sources of different brightness, and in different atmospheric conditions are presented. These measurements, based on observations made with the 91 cm Cassegrain telescope of the Catania Astrophysical Observatory, are used to check the photometer accuracy and compare its performance with that of standard photometers

Living arrangements in Sub-Saharan Africa between ethnicity and modernization

In Sub-Saharan Africa the phenomenology of living arrangements is of great interest owing to the extraordinary diversification and complexity of the traditional family patterns. In particular, the predominance of the enlarged family over the biological family is a feature that traditionally distinguishes the conception and the organization of the Sub-Saharan African family. It is a debatable question whether this feature is everlasting or it evolves with the deep economic and social changes occurring in Sub-Saharan African countries. We aim to analyse the living arrangements in several Sub-Saharan countries and in their main ethnic groups, attempting to enlighten the interaction between “modernization” and cultural heritage in shaping family patterns. A temporal perspective has been adopted, as well as the ethnic and rural/urban differentials. The analyses consider ten countries in different geographical areas of Sub-Saharan Africa, where at least two waves of Demographic and Health Surveys were carried out between 1990 and 2013. To detail the analyses, we also consider the most representative ethnic groups for each country (in all 38 ethnic groups). After recalling the theoretical background and present preliminary descriptive findings, the classical procedure of factor analysis is used with the principal components method, followed by an hierarchical classification analysis. Our results show that it is not possible to propose general models for the great traditional geographical areas in Africa. The trends and the rural-urban differentials are not exhaustively explained by modernization factors. The results are in line with the literature outcomes that supported the process of growing variability of living arrangements and the increase of new family models, rather than the existence of a convergence process on a single nuclear family pattern. Ethnic background is confirmed as a valid interpretative key, necessary to understand the cultural substrate in which the evolutive factors brought by globalization act

Audits and inspections are never enough: a critique to enhance food safety

Internal and external food safety audits are conducted to assess the safety and quality of food including on-farm production, manufacturing practices, sanitation, and hygiene. Some auditors are direct stakeholders that are employed by food establishments to conduct internal audits, while other auditors may represent the interests of a second party purchaser or a third-party auditing agency. Some buyers conduct their own audits or additional testing, while some buyers trust the results of third-party audits or inspections. Third-party auditors, however, use various food safety audit standards and most do not have a vested interest in the products being sold. Audits are conducted under a proprietary standard, while food safety inspections are generally conducted within a legal framework. There have been many foodborne illness outbreaks linked to food processors that have passed third-party audits and inspections, raising questions about the utility of both. Supporters argue third-party audits are a way to ensure food safety in an era of dwindling economic resources. Critics contend that while external audits and inspections can be a valuable tool to help ensure safe food, such activities represent only a snapshot in time. This paper identifies limitations of food safety inspections and audits and provides recommendations for strengthening the system, based on developing a strong food safety culture, including risk-based verification steps, throughout the food safety system

Neutron polarisation analysis of Polymer: Fullerene blends for organic photovoltaics

The photogeneration process in polymer-fullerene organic solar cells relies strongly on the nanostructure and on the nano/picosecond dynamics occurring in these complex blends. Elastic and inelastic neutron scattering techniques are valuable tools with which to investigate those features in the appropriate time and space domains. In particular, quasi-elastic neutron scattering (QENS) connects useful structural and dynamical information by the measurement of dynamical incoherent (single particle) fluctuations in soft materials as a function of lengthscale. Extraction of these fluctuation rates can, however, be hampered by the presence of coherent contributions, originating from elastic scattering, and/or inelastic scattering modes which overlap in the space/time domain with the incoherent single-particle motions. As we have already seen in a previous study [1], this happens in poly(3-hexylthiophene) (P3HT) and [6,6]-Phenyl C61 butyric acid methyl ester (PCBM) solid blends, in which the coherent contribution arising from the PCBM crystalline phase seems to affect the interpretation of the polymer dynamics. Here, we utilise neutron polarisation analysis as an effective tool to separate coherent and incoherent contributions and make QENS data analysis of these blends more reliable

Differential Splicing Alters Subcellular Localization of the Alpha but not Beta Isoform of the MIER1 Transcriptional Regulator in Breast Cancer Cells

MIER1 was originally identified in a screen for novel fibroblast growth factor activated early response genes. The mier1 gene gives rise to multiple transcripts encoding protein isoforms that differ in their amino (N-) and carboxy (C-) termini. Much of the work to date has focused on the two C-terminal variants, MIER1α and β, both of which have been shown to function as transcriptional repressors. Our previous work revealed a dramatic shift in MIER1α subcellular localization from nuclear in normal breast tissue to cytoplasmic in invasive breast carcinoma, suggesting that loss of nuclear MIER1α may play a role in breast cancer development. In the present study, we investigated whether alternative splicing to include a cassette exon and produce an N–terminal variant of MIER1α affects its subcellular localization in MCF7 breast carcinoma cells. We demonstrate that this cassette exon, exon 3A, encodes a consensus leucine-rich nuclear export signal (NES). Inclusion of this exon in MIER1α to produce the MIER1-3Aα isoform altered its subcellular distribution in MCF7 cells from 81% nuclear to 2% nuclear and this change in localization was abrogated by mutation of critical leucines within the NES. Treatment with leptomycin B (LMB), an inhibitor of the nuclear export receptor CRM1, resulted in a significant increase in the percentage of cells with nuclear MIER1-3Aα, from 4% to 53%, demonstrating that cytoplasmic localization of this isoform was due to CRM1-dependent nuclear export. Inclusion of exon 3A in MIER1β to produce the N-terminal variant MIER1-3Aβ however had little effect on the nuclear targeting of this isoform. Our results demonstrate that alternative splicing to include exon 3A specifically affects the localization pattern of the α isoform