Near-UV Observations of CS29497-030: New Constraints on Neutron-Capture Nucleosynthesis Processes

Employing spectra obtained with the new Keck I HIRES near-UV sensitive detector, we have performed a comprehensive chemical composition analysis of the binary blue metal-poor star CS29497-030. Abundances for 29 elements and upper limits for an additional seven have been derived, concentrating on elements largely produced via neutron-capture nucleosynthesis. Included in our analysis are the two elements that define the termination point of the slow neutron-capture process, lead and bismuth. We determine an extremely high value of [Pb/Fe] = +3.65 +/- 0.07 (sigma = 0.13) from three features, supporting the single-feature result obtained in previous studies. We also detect Bi for the first time in a metal-poor star. Our derived Bi/Pb ratio is in accord with those predicted from the most recent FRANEC calculations of the slow neutron-capture process in low-mass AGB stars. We find that the neutron-capture elemental abundances of CS29497-030 are best explained by an AGB model that also includes very significant amounts of pre-enrichment of rapid neutron-capture process material in the protostellar cloud out of which the CS29497-030 binary system formed. Thus, CS29497-030 is both an ``r+s'' and ``extrinsic AGB'' star. Furthermore, we find that the mass of the AGB model can be further constrained by the abundance of the light odd-element [Na/Fe] which is sensitive to the neutron excess.Comment: 7 pages = 4 + 2 colour encapsulated postscript figures + 1 table; to appear in ApJ Letters; additional jpeg figure available at ftp://www.astro.caltech.edu/users/iii/cs2949703

Micro-ethics for participatory design with marginalised children

Marginalised children are uniquely vulnerable within western societies. Conducting participatory design research with them comes with particular ethical challenges, some of which we illustrate in this paper. Through several examples across two different participatory design projects (one with autistic children, another with visually impaired children), we reflect on the often overlooked tensions on the level of micro-ethics. We argue we are often required to rely on multiple moral frames of references. We discuss issues that the immediate interaction between researchers and marginalised children in participatory projects can bring and offer an understanding of how micro-ethics manifest in these collaborations. We contribute to a theoretical exploration of ethical encounters based on empirical grounds, which can guide other researchers in their participatory endeavours

Occurrence of lactational mastitis and medical management: a prospective cohort study in Glasgow

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background Lactational mastitis is a painful, debilitating condition that if inappropriately managed, may lead women to discontinue breastfeeding prematurely. The aim of this paper is to report the incidence of mastitis in the first six months postpartum in a Scottish population, its impact on breastfeeding duration and to describe the type and appropriateness of the support and management received by affected women from health professionals. Methods A longitudinal study of 420 breastfeeding women was undertaken in Glasgow in 2004/05. Participants were recruited and completed a baseline questionnaire before discharge from hospital. Cases of mastitis were reported either directly to the researchers or were detected during regular follow-up telephone interviews at weeks 3, 8, 18 and 26. Women experiencing mastitis provided further information of their symptoms and the management and advice they received from health professionals. Results In total, 74 women (18%) experienced at least one episode of mastitis. More than one half of initial episodes (53%) occurred within the first four weeks postpartum. One in ten women (6/57) were inappropriately advised to either stop breastfeeding from the affected breast or to discontinue breastfeeding altogether. Conclusion Approximately one in six women is likely to experience one or more episodes of mastitis whilst breastfeeding. A small but clinically important proportion of women continue to receive inappropriate management advice from health professionals which, if followed, could lead them to unnecessarily deprive their infants prematurely of the known nutritional and immunological benefits of breast milk

Cytochrome cM decreases photosynthesis under photomixotrophy in Synechocystis sp. PCC 6803

Photomixotrophy is a metabolic state that enables photosynthetic microorganisms to simultaneously perform photosynthesis and metabolism of imported organic carbon substrates. This process is complicated in cyanobacteria, since many, including Synechocystis sp. PCC 6803, conduct photosynthesis and respiration in an interlinked thylakoid membrane electron transport chain. Under photomixotrophy, the cell must therefore tightly regulate electron fluxes from photosynthetic and respiratory complexes. In this study, we demonstrate, via characterization of photosynthetic apparatus and the proteome, that photomixotrophic growth results in a gradual inhibition of QA- reoxidation in wild-type Synechocystis, which largely decreases photosynthesis over 3 d of growth. This process is circumvented by deleting the gene encoding cytochrome cM (CytM), a cryptic c-type heme protein widespread in cyanobacteria. The ΔCytM strain maintained active photosynthesis over the 3-d period, demonstrated by high photosynthetic O2 and CO2 fluxes and effective yields of PSI and PSII. Overall, this resulted in a higher growth rate compared to that of the wild type, which was maintained by accumulation of proteins involved in phosphate and metal uptake, and cofactor biosynthetic enzymes. While the exact role of CytM has not been determined, a mutant deficient in the thylakoid-localized respiratory terminal oxidases and CytM (ΔCox/Cyd/CytM) displayed a phenotype similar to that of ΔCytM under photomixotrophy. This, in combination with other physiological data, and in contrast to a previous hypothesis, suggests that CytM does not transfer electrons to these complexes. In summary, our data suggest that CytM may have a regulatory role in photomixotrophy by modulating the photosynthetic capacity of cells

A Systematic Review of Reported Cost for Smear and Culture Tests during Multidrug-Resistant Tuberculosis Treatment

Background: In 2011, World Health Organization revised its recommendation for microbiological monitoring during treatment for multidrug-resistant tuberculosis (MDR-TB) by increasing the frequency of culture examination from quarterly to monthly after culture conversion. Implementing the recommendation requires substantial additional investment in laboratory infrastructure. The objective of this review is to provide cost evidence that is needed for national TB programs to budget for optimal monitoring strategies. Methods and Findings: We conducted the first systematic literature review on unit cost estimates of three monitoring strategies: 1) smear only; 2) culture only; 3) combined smear and culture. 26 peer-reviewed studies were selected by searching 10 databases in English and Chinese for literature published between 1995 and 2012. Cost estimates were converted into 2010 constant USD and international dollars. We assessed the quality of the estimates using a matrix with five essential elements and provided a cost projection for the combined smear and culture tests where the data were available. The 26 studies reported the cost estimates in 16 predominantly high- or middle-income countries from 1993 to 2009. The estimated unit cost for smear, culture, and combined tests ranges from $0.26 to$10.50, $1.63 to$62.01, and $26.73 to$39.57, respectively. The ratio of culture to smear costs varies from 1.35 to 11.98. The wide range of estimates is likely attributable to using different laboratory methods in different regions and years and differing practices in collecting and reporting cost data. Most studies did not report information critical for generalizing their conclusions. Conclusion: The paucity and low quality of unit cost estimates for TB monitoring in resource-poor settings impose technical challenges in predicting the resources needed for strengthening microbiological monitoring. To improve the validity and comparability of the cost data, we strongly advocate the data collection, estimation, and reporting follow protocols proposed by WHO

Xpert MTB/RIF for diagnosis of tuberculosis and drug-resistant tuberculosis: a cost and affordability analysis.

Xpert MTB/RIF is a rapid test to diagnose tuberculosis (TB) and rifampicin-resistant TB. Cost and affordability will influence its uptake. We assessed the cost, globally and in 36 high-burden countries, of two strategies for diagnosing TB and multidrug-resistant (MDR)-TB: Xpert with follow-on diagnostics, and conventional diagnostics. Costs were compared with funding available for TB care and control, and donor investments in HIV prevention and care. Using Xpert to diagnose MDR-TB would cost US$70-90 million per year globally and be lower cost than conventional diagnostics globally and in all high-burden countries. Diagnosing TB in HIV-positive people using Xpert would also cost US$90-101 million per year and be lower cost than conventional diagnostics globally and in 33 out of 36 high-burden countries. Testing everyone with TB signs and symptoms would cost US$434-468 million per year globally, much more than conventional diagnostics. However, in European countries, Brazil and South Africa, the cost would represent <10% of TB funding. Introducing Xpert to diagnose MDR-TB and to diagnose TB in HIV-positive people is warranted in many countries. Using it to test everyone with TB signs and symptoms is affordable in several middle-income countries, but financial viability in low-income countries requires large increases in TB funding and/or further price reductions

Rats that sign-track are resistant to Pavlovian but not instrumental extinction

Individuals vary in the extent to which they attribute incentive salience to a discrete cue (conditioned stimulus; CS) that predicts reward delivery (unconditioned stimulus; US), which results in some individuals approaching and interacting with the CS (sign-trackers; STs) more than others (goal-trackers; GTs). Here we asked how periods of non-reinforcement influence conditioned responding in STs vs. GTs, in both Pavlovian and instrumental tasks. After classifying rats as STs or GTs by pairing a retractable lever (the CS) with the delivery of a food pellet (US), we introduced periods of non-reinforcement, first by simply withholding the US (i.e., extinction training; experiment 1), then by signaling alternating periods of reward (R) and non-reward (NR) within the same session (experiments 2 and 3). We also examined how alternating R and NR periods influenced instrumental responding for food (experiment 4). STs and GTs did not differ in their ability to discriminate between R and NR periods in the instrumental task. However, in Pavlovian settings STs and GTs responded to periods of non-reward very differently. Relative to STs, GTs very rapidly modified their behavior in response to periods of non-reward, showing much faster extinction and better and faster discrimination between R and NR conditions. These results highlight differences between Pavlovian and instrumental extinction learning, and suggest that if a Pavlovian CS is strongly attributed with incentive salience, as in STs, it may continue to bias attention toward it, and to facilitate persistent and relatively inflexible responding, even when it is no longer followed by reward

The Rise of the s-Process in the Galaxy

From newly-obtained high-resolution, high signal-to-noise ratio spectra the abundances of the elements La and Eu have been determined over the stellar metallicity range -3<[Fe/H]<+0.3 in 159 giant and dwarf stars. Lanthanum is predominantly made by the s-process in the solar system, while Eu owes most of its solar system abundance to the r-process. The changing ratio of these elements in stars over a wide metallicity range traces the changing contributions of these two processes to the Galactic abundance mix. Large s-process abundances can be the result of mass transfer from very evolved stars, so to identify these cases, we also report carbon abundances in our metal-poor stars. Results indicate that the s-process may be active as early as [Fe/H]=-2.6, alalthough we also find that some stars as metal-rich as [Fe/H]=-1 show no strong indication of s-process enrichment. There is a significant spread in the level of s-process enrichment even at solar metallicity.Comment: 64 pages, 15 figures; ApJ 2004 in pres

Intraoperative electrocochleographic characteristics of auditory neuropathy spectrum disorder in cochlear implant subjects

Auditory neuropathy spectrum disorder (ANSD) is characterized by an apparent discrepancy between measures of cochlear and neural function based on auditory brainstem response (ABR) testing. Clinical indicators of ANSD are a present cochlear microphonic (CM) with small or absent wave V. Many identified ANSD patients have speech impairment severe enough that cochlear implantation (CI) is indicated. To better understand the cochleae identified with ANSD that lead to a CI, we performed intraoperative round window electrocochleography (ECochG) to tone bursts in children (n = 167) and adults (n = 163). Magnitudes of the responses to tones of different frequencies were summed to measure the “total response” (ECochG-TR), a metric often dominated by hair cell activity, and auditory nerve activity was estimated visually from the compound action potential (CAP) and auditory nerve neurophonic (ANN) as a ranked “Nerve Score”. Subjects identified as ANSD (45 ears in children, 3 in adults) had higher values of ECochG-TR than adult and pediatric subjects also receiving CIs not identified as ANSD. However, nerve scores of the ANSD group were similar to the other cohorts, although dominated by the ANN to low frequencies more than in the non-ANSD groups. To high frequencies, the common morphology of ANSD cases was a large CM and summating potential, and small or absent CAP. Common morphologies in other groups were either only a CM, or a combination of CM and CAP. These results indicate that responses to high frequencies, derived primarily from hair cells, are the main source of the CM used to evaluate ANSD in the clinical setting. However, the clinical tests do not capture the wide range of neural activity seen to low frequency sounds