184 research outputs found

    Low energy threshold corrections to neutrino masses and mixing angles

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    We compute the low energy threshold corrections to neutrino masses and mixing in the Standard Model (SM) and its minimal supersymmetric version, using the effective theory technique. We demonstrate that they stabilize the renormalization group (RG) running with respect to the choice of the scale to which the RG equation is integrated. This confirms the correctness of the recent re-derivation of the RGE for the SM in hep-ph/0108005. The explicit formulae for the low energy threshold corrections corrections can be applied to specific models of neutrino masses and mixing.Comment: 20 pages, 2 postscript figure

    Sporangia and Spores in the Fern Genera Spicantopsis and Struthiopteris (Blechnaceae, Polypodiopsida)

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    Struthiopteris (Blechnaceae) has recently been classified on the basis of molecular and morphological evidence, and some of its species are now included in the sister genus Spicantopsis. However, the lack of studies on several important morphological features impedes a sound assessment of their congruence with this new systematic arrangement, as well as of their range of variation and taxonomic value in this group of ferns. Here we present a study on the spores and sporangia using both light and scanning electron microscopy in Struthiopteris and Spicantopsis, using samples of all their species, and almost all their varieties. We provide full morphological descriptions of the spores and sporangia of all these taxa. We point out that the perispore structure and ornamentation and the number and the thickness of stomium cells in the sporangium clearly distinguish both generaThe Universidad Complutense de Madrid partially supported this research through the funding of a project PR26/16-20295, and a field trip to Iceland (International Mobility Program 2016

    Evaluation of protamines 1 and 2 transcript contents in spermatozoa from asthenozoospermic men.

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    During mammalian spermatogenesis, the chromatin structure undergoes substantial condensation. The key role in this process is played by protamines 1 and 2 (PRM1, PRM2). We attempted to compare the levels of PRM1 and PRM2 transcripts in mature spermatozoa of normospermic and asthenozoospermic men. Human ejaculates from normozoospermic (n=70) and asthenozoospermic (n=100) donors were purified by centrifugation through discontinuous Percoll density gradient. RNA was isolated from spermatozoa according to the ChomczyĂąski and Sacchi method, treated with DNase I, and reverse-transcribed into cDNA. Using reverse transcription and real-time quantitative polymerase chain reaction analysis, we found a reduction in the levels of PRM1 and PRM2 transcripts in spermatozoa from asthenozoospermic men, as compared to controls (

    Benchmarking and reducing length of stay in Dutch hospitals

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    <p>Abstract</p> <p>Background</p> <p>To assess the development of and variation in lengths of stay in Dutch hospitals and to determine the potential reduction in hospital days if all Dutch hospitals would have an average length of stay equal to that of benchmark hospitals.</p> <p>Methods</p> <p>The potential reduction was calculated using data obtained from 69 hospitals that participated in the National Medical Registration (LMR). For each hospital, the average length of stay was adjusted for differences in type of admission (clinical or day-care admission) and case mix (age, diagnosis and procedure). We calculated the number of hospital days that theoretically could be saved by (i) counting unnecessary clinical admissions as day cases whenever possible, and (ii) treating all remaining clinical patients with a length of stay equal to the benchmark (15<sup>th </sup>percentile length of stay hospital).</p> <p>Results</p> <p>The average (mean) length of stay in Dutch hospitals decreased from 14 days in 1980 to 7 days in 2006. In 2006 more than 80% of all hospitals reached an average length of stay shorter than the 15th percentile hospital in the year 2000. In 2006 the mean length of stay ranged from 5.1 to 8.7 days. If the average length of stay of the 15<sup>th </sup>percentile hospital in 2006 is identified as the standard that other hospitals can achieve, a 14% reduction of hospital days can be attained. This percentage varied substantially across medical specialties. Extrapolating the potential reduction of hospital days of the 69 hospitals to all 98 Dutch hospitals yielded a total savings of 1.8 million hospital days (2006). The average length of stay in Dutch hospitals if all hospitals were able to treat their patients as the 15<sup>th </sup>percentile hospital would be 6 days and the number of day cases would increase by 13%.</p> <p>Conclusion</p> <p>Hospitals in the Netherlands vary substantially in case mix adjusted length of stay. Benchmarking – using the method presented – shows the potential for efficiency improvement which can be realized by decreasing inputs (e.g. available beds for inpatient care). Future research should focus on the effect of length of stay reduction programs on outputs such as quality of care.</p

    HBM4EU chromates study - Usefulness of measurement of blood chromium levels in the assessment of occupational Cr(VI) exposure

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    Occupational exposures to hexavalent Chromium (Cr(VI)) can occur in welding, hot working stainless steel processing, chrome plating, spray painting and coating activities. Recently, within the human biomonitoring for Europe initiative (HBM4EU), a study was performed to assess the suitability of different biomarkers to assess the exposure to Cr(VI) in various job tasks. Blood-based biomarkers may prove useful when more specific information on systemic and intracellular bioavailability is necessary. To this aim, concentrations of Cr in red blood cells (RBC-Cr) and in plasma (P–Cr) were analyzed in 345 Cr(VI) exposed workers and 175 controls to understand how these biomarkers may be affected by variable levels of exposure and job procedures. Compared to controls, significantly higher RBC-Cr levels were observed in bath plating and paint application workers, but not in welders, while all the 3 groups had significantly greater P–Cr concentrations. RBC-Cr and P–Cr in chrome platers showed a high correlation with Cr(VI) in inhalable dust, outside respiratory protective equipment (RPE), while such correlation could not be determined in welders. In platers, the use of RPE had a significant impact on the relationship between blood biomarkers and Cr(VI) in inhalable and respirable dust. Low correlations between P–Cr and RBC-Cr may reflect a difference in kinetics. This study showed that Cr-blood-based biomarkers can provide information on how workplace exposure translates into systemic availability of Cr(III) (extracellular, P–Cr) and Cr(VI) (intracellular, RBC-Cr). Further studies are needed to fully appreciate their use in an occupational health and safety context

    reflection and lessons learnt from designing and undertaking a collaborative European biomonitoring study on occupational exposure to hexavalent chromium

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    The EU human biomonitoring initiative, HBM4EU, aims to co-ordinate and advance human biomonitoring (HBM) across Europe. As part of HBM4EU, we presented a protocol for a multicentre study to characterize occupational exposure to hexavalent chromium (Cr(VI)) in nine European countries (HBM4EU chromates study). This study intended to collect data on current occupational exposure and to test new indicators for chromium (Cr) biomonitoring (Cr(VI) in exhaled breath condensate and Cr in red blood cells), in addition to traditional urinary total Cr analyses. Also, data from occupational hygiene samples and biomarkers of early biological effects, including genetic and epigenetic effects, was obtained, complementing the biomonitoring information. Data collection and analysis was completed, with the project findings being made separately available. As HBM4EU prepares to embark on further European wide biomonitoring studies, we considered it important to reflect on the experiences gained through our harmonised approach. Several practical aspects are highlighted for improvement in future studies, e.g., more thorough/earlier training on the implementation of standard operating procedures for field researchers, training on the use of the data entry template, as well as improved company communications. The HBM4EU chromates study team considered that the study had successfully demonstrated the feasibility of conducting a harmonised multicentre investigation able to achieve the research aims and objectives. This was largely attributable to the engaged multidisciplinary network, committed to deliver clearly understood goals. Such networks take time and investment to develop, but are priceless in terms of their ability to deliver and facilitate knowledge sharing and collaboration.publishersversionpublishe
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