What are the living conditions and health status of those who don't report their migration status? a population-based study in Chile

BACKGROUND: Undocumented immigrants are likely to be missing from population databases, making it impossible to identify an accurate sampling frame in migration research. No population-based data has been collected in Chile regarding the living conditions and health status of undocumented immigrants. However, the CASEN survey (Caracterizacion Socio- Economica Nacional) asked about migration status in Chile for the first time in 2006 and provides an opportunity to set the base for future analysis of available migration data. We explored the living conditions and health of self-reported immigrants and respondents who preferred not to report their migration status in this survey. METHODS: Cross-sectional secondary analysis of CASEN survey in Chile in 2006. Outcomes: any disability, illness/accident, hospitalization/surgery, cancer/chronic condition (all binary variables); and the number of medical/emergency attentions received (count variables). Covariates: Demographics (age, sex, marital status, urban/rural, ethnicity), socioeconomic status (education level, employment status and household income), and material standard of living (overcrowding, sanitation, housing quality). Weighted regression models were estimated for each health outcome, crude and adjusted by sets of covariates, in STATA 10.0. RESULTS: About 1% of the total sample reported being immigrants and 0.7% preferred not to report their migration status (Migration Status - Missing Values; MS-MV). The MS-MV lived in more deprived conditions and reported a higher rate of health problems than immigrants. Some gender differences were observed by health status among immigrants and the MS-MV but they were not statistically significant. Regressions indicated that age, sex, SES and material factors consistently affected MS-MVs’ chance of presenting poor health and these patterns were different to those found among immigrants. Great heterogeneity in both the MS-MV and the immigrants, as indicated by wide confidence intervals, prevented the identification of other significantly associated covariates. CONCLUSION: This is the first study to look at the living conditions and health of those that preferred not to respond their migration status in Chile. Respondents that do not report their migration status are vulnerable to poor health and may represent undocumented immigrants. Surveys that fail to identify these people are likely to misrepresent the experiences of immigrants and further quantitative and qualitative research is urgently required

Repeated evolution of self-compatibility for reproductive assurance

Sexual reproduction in eukaryotes requires the fusion of two compatible gametes of opposite sexes or mating types. To meet the challenge of finding a mating partner with compatible gametes evolutionary mechanisms such as hermaphroditism and self-fertilisation have repeatedly evolved. Combining insight from comparative genomics, computer simulations and experimental evolution in fission yeast, we shed light on the conditions promoting separate mating types or self-compatibility by mating-type switching. Analogous to multiple independent transitions between switchers and non-switchers in natural populations mediated by structural genomic changes, novel switching genotypes were readily evolving under selection in experimental populations. Detailed fitness measurements accompanied by computer simulations show the benefits and costs of switching during sexual and asexual reproduction governing the occurrence of both strategies in nature. Our findings illuminate the trade-off between the benefits of reproductive assurance and its fitness costs under benign conditions governing the evolution of self-compatibility

Practical electronic auction scheme with strong anonymity and bidding privacy

[[abstract]]In 2003, Chang and Chang proposed an efficient and anonymous auction protocol with freewheeling bids. They claimed that their scheme could ensure the bidders' anonymity and secure confidentiality. Later, Jiang et al. pointed out that their scheme could not withstand the man-in-the-middle attacks; during this time, Jiang et al. proposed an improved scheme based on the scheme by Chang and Chang. In 2006, Chang and Chang proposed an anonymous auction scheme that was much more efficient than the above mentioned schemes. However, all of these three schemes were unable to achieve strong anonymity, bidding privacy, and secret bidding prices for sealed-bids. This article proposes a new scheme to resolve the above problems in which two managers and zero knowledge proof are used. The proposed scheme can be widely applied in any sensitive auction (e.g., auctions of cosmetics, medical services, etc.). Moreover, the proposed scheme also satisfies the following requirements: (1) bidding privacy, (2) strong anonymity, (3) secret bidding prices, (4) unforgeability, (5) verifiability, (6) non-repudiation, (7) traceability, (8) one-time registration and (9) easy revocation. (C) 2011 Elsevier Inc. All rights reserved.[[note]]SC

OBSERVATION OF A CHARMED NEUTRAL MESON PRODUCED IN A HIGH-ENERGY PHOTON INTERACTION

The production and decay of a D0bar meson have been observed in a nuclear emulsion exposed to a photon beam from the CERN super proton synchroton in conjunction with the Omega spectrometer. All the decay products have been detected and measured in the emulsion and in the spectrometer. The mass of the charmed particle is 1866 \ub1 8 MeV/c2 and its decay time is (2.26 \ub1 0.05) 7 10 1214 s. Reference