414 research outputs found

    ARCHAEOLOGICAL GEOPHYSICS IN PORTUGAL – SOME SURVEY EXAMPLES

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    The first attempts to apply geophysical methods to archaeological sites in Portugal date from the mid-sixties of the last century. Since then, geophysical methods have been used more and more frequently to help on archaeological site recognition, delineating buried structures, and help on excavating strategies. The first geophysical methods used in Portugal were geoelectrical methods followed by magnetic methods; today those two methods are still used; however, georadar and electrical resistivity tomography have also been used on a routine basis whenever the local conditions allow their use. Four archaeological sites will be described as examples on the use of geophysical methods in Archaeology. Two of them are from roman times (the Roman Villa of Tourega, in central Portugal and the Roman town of Troia, in the west coast of Portugal), one is from Neolithic times (a burial mound in central Portugal); the last one is a recent archaeological site (eighteenth century) and has to do with the location of a crypt known to exist in the garden of the Portuguese Legislature in Lisbon. Only electrical resistivity tomography and georadar were used. The sites were chosen because in all of them there were already previously excavated areas or there were plans for future excavation. When choosing those sites the idea was to be able to compare the interpretations of the geophysical data with the results of the excavations

    Fluoromycobacteriophages for rapid, specific, and sensitive antibiotic susceptibility testing of Mycobacterium tuberculosis

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    Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. © 2009 Piuri et al

    Accreting Protoplanets in the LkCa 15 Transition Disk

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    Exoplanet detections have revolutionized astronomy, offering new insights into solar system architecture and planet demographics. While nearly 1900 exoplanets have now been discovered and confirmed, none are still in the process of formation. Transition discs, protoplanetary disks with inner clearings best explained by the influence of accreting planets, are natural laboratories for the study of planet formation. Some transition discs show evidence for the presence of young planets in the form of disc asymmetries or infrared sources detected within their clearings, as in the case of LkCa 15. Attempts to observe directly signatures of accretion onto protoplanets have hitherto proven unsuccessful. Here we report adaptive optics observations of LkCa 15 that probe within the disc clearing. With accurate source positions over multiple epochs spanning 2009 - 2015, we infer the presence of multiple companions on Keplerian orbits. We directly detect H{\alpha} emission from the innermost companion, LkCa 15 b, evincing hot (~10,000 K) gas falling deep into the potential well of an accreting protoplanet.Comment: 35 pages, 3 figures, 1 table, 9 extended data item

    Accurate masses and radii of normal stars: modern results and applications

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    This paper presents and discusses a critical compilation of accurate, fundamental determinations of stellar masses and radii. We have identified 95 detached binary systems containing 190 stars (94 eclipsing systems, and alpha Centauri) that satisfy our criterion that the mass and radius of both stars be known to 3% or better. To these we add interstellar reddening, effective temperature, metal abundance, rotational velocity and apsidal motion determinations when available, and we compute a number of other physical parameters, notably luminosity and distance. We discuss the use of this information for testing models of stellar evolution. The amount and quality of the data also allow us to analyse the tidal evolution of the systems in considerable depth, testing prescriptions of rotational synchronisation and orbital circularisation in greater detail than possible before. The new data also enable us to derive empirical calibrations of M and R for single (post-) main-sequence stars above 0.6 M(Sun). Simple, polynomial functions of T(eff), log g and [Fe/H] yield M and R with errors of 6% and 3%, respectively. Excellent agreement is found with independent determinations for host stars of transiting extrasolar planets, and good agreement with determinations of M and R from stellar models as constrained by trigonometric parallaxes and spectroscopic values of T(eff) and [Fe/H]. Finally, we list a set of 23 interferometric binaries with masses known to better than 3%, but without fundamental radius determinations (except alpha Aur). We discuss the prospects for improving these and other stellar parameters in the near future.Comment: 56 pages including figures and tables. To appear in The Astronomy and Astrophysics Review. Ascii versions of the tables will appear in the online version of the articl

    Using mid-level cadres as substitutes for internationally mobile health professionals in Africa. A desk review

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    BACKGROUND: Substitute health workers are cadres who take on some of the functions and roles normally reserved for internationally recognized health professionals such as doctors, pharmacists and nurses but who usually receive shorter pre-service training and possess lower qualifications. METHODS: A desk review is conducted on the education, regulation, scopes of practice, specialization, nomenclature, retention and cost-effectiveness of substitute health workers in terms of their utilization in countries such as Tanzania, Malawi, Mozambique, Zambia, Ghana etc., using curricula, evaluations and key-informant questionnaires. RESULTS: The cost-effectiveness of using substitutes and their relative retention within countries and in rural communities underlies their advantages to African health systems. Some studies comparing clinical officers and doctors show minimal differences in outcomes to patients. Specialized substitutes provide services in disciplines such as surgery, ophthalmology, orthopedics, radiology, dermatology, anesthesiology and dentistry, demonstrating a general bias of use for clinical services. CONCLUSIONS: The findings raise interest in expanding the use of substitute cadres, as the demands of expanding access to services such as antiretroviral treatment requires substantial human resources capacity. Understanding the roles and conditions under which such cadres best function, and managing the skepticism and professional turf protection that restricts their potential, will assist in effective utilization of substitutes

    Omega-3 supplementation from pregnancy to postpartum to prevent depressive symptoms: a randomized placebo-controlled trial

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    Background: Low n-3 polyunsaturated fatty acids (PUFAs) has been linked to depression, but the preventive effect of n-3PUFAs supplementation on maternal depression needs further investigation. We aimed to evaluate the efficacy of a daily dose of n-3 PUFAs supplementation (fish oil) on the prevention of postpartum depression (PPD). Methods: A randomized, placebo-controlled, double blind trial was designed and nested into a cohort study conducted in Rio de Janeiro, Brazil. Sixty pregnant women identified as being at risk for PPD were invited and randomly assigned to receive fish oil capsules [1.8 g (1.08 g of Eicosapentaenoic (EPA) and 0.72 g of Docosapentaenoic (DHA) acids)] or placebo (control). The Edinburgh Postnatal Depression Scale (EPDS) was scored at 5–13 (T0, baseline), 22–24 (T1), 30–32 weeks of gestation (T2) and 4–6 weeks’ postpartum (T3). Supplementation started at week 22–24 of gestation (T1) and lasted for 16 weeks. Serum fatty acids were assayed to evaluate compliance. Prevalence of EPDS ≥11 was the primary outcome, and mean and changes in EPDS score, length of gestation, and birth weight the secondary outcomes. Linear mixed-effect (LME) and random-intercept logistic regression models were performed to test the effect of fish oil supplementation on prevalence of EPDS ≥11 and EPDS scores variation. Results: In intention-to-treat (ITT) analysis, at 30–32 weeks’ gestation women in the fish oil presented higher serum concentration of EPA, DHA and lower n-6/n-3 ratio comparing to the control group. There were no differences between intervention and control groups in the prevalence of EPDS ≥11, EPDS scores over time, or in changes in EPDS scores from pregnancy to postpartum in either the ITT or per-protocol analyses. Women in the fish oil group with previous history of depression presented a higher reduction on the EPDS score from the second to the third trimester in the fish oil comparing to the control group in the ITT analyses [−1.0 (−3.0–0.0) vs. -0.0 (−1.0–3.0), P = 0.038). These results were confirmed on the LME model (β = −3.441; 95%CI: -6.532– -0.350, P = 0.029). Conclusion: Daily supplementation of 1.8 g of n-3 PUFAs during 16 weeks did not prevent maternal depressive symptoms in a sample of Brazilian women

    Task shifting in maternal and newborn care: a non-inferiority study examining delegation of antenatal counseling to lay nurse aides supported by job aids in Benin

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    <p>Abstract</p> <p>Background</p> <p>Shifting the role of counseling to less skilled workers may improve efficiency and coverage of health services, but evidence is needed on the impact of substitution on quality of care. This research explored the influence of delegating maternal and newborn counseling responsibilities to clinic-based lay nurse aides on the quality of counseling provided as part of a task shifting initiative to expand their role.</p> <p>Methods</p> <p>Nurse-midwives and lay nurse aides in seven public maternities were trained to use job aids to improve counseling in maternal and newborn care. Quality of counseling and maternal knowledge were assessed using direct observation of antenatal consultations and patient exit interviews. Both provider types were interviewed to examine perceptions regarding the task shift. To compare provider performance levels, non-inferiority analyses were conducted where non-inferiority was demonstrated if the lower confidence limit of the performance difference did not exceed a margin of 10 percentage points.</p> <p>Results</p> <p>Mean percent of recommended messages provided by lay nurse aides was non-inferior to counseling by nurse-midwives in adjusted analyses for birth preparedness (β = -0.0, 95% CI: -9.0, 9.1), danger sign recognition (β = 4.7, 95% CI: -5.1, 14.6), and clean delivery (β = 1.4, 95% CI: -9.4, 12.3). Lay nurse aides demonstrated superior performance for communication on general prenatal care (β = 15.7, 95% CI: 7.0, 24.4), although non-inferiority was not achieved for newborn care counseling (β = -7.3, 95% CI: -23.1, 8.4). The proportion of women with correct knowledge was significantly higher among those counseled by lay nurse aides as compared to nurse-midwives in general prenatal care (β = 23.8, 95% CI: 15.7, 32.0), birth preparedness (β = 12.7, 95% CI: 5.2, 20.1), and danger sign recognition (β = 8.6, 95% CI: 3.3, 13.9). Both cadres had positive opinions regarding task shifting, although several preferred 'task sharing' over full delegation.</p> <p>Conclusions</p> <p>Lay nurse aides can provide effective antenatal counseling in maternal and newborn care in facility-based settings, provided they receive adequate training and support. Efforts are needed to improve management of human resources to ensure that effective mechanisms for regulating and financing task shifting are sustained.</p
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