482 research outputs found

    Are patterns of fine-scale spatial genetic structure consistent between sites within tropical tree species?

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    JRS was funded by the Swiss National Science Foundation (SNF) (http://www.snf.ch/en/Pages/default.aspx) grant number PDFMP3_132479 / 1 awarded to JG. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Processing The Interspecies Quorum-Sensing Signal Autoinducer-2 (AI-2) Characterization Of Phospho-(S)-4,5-Dihydroxy-2,3-Pentanedione Isomerization By LsrG Protein

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    The molecule (S)-4,5-dihydroxy-2,3-pentanedione (DPD) is produced by many different species of bacteria and is the precursor of the signal molecule autoinducer-2 (AI-2). AI-2 mediates interspecies communication and facilitates regulation of bacterial behaviors such as biofilm formation and virulence. A variety of bacterial species have the ability to sequester and process the AI-2 present in their environment, thereby interfering with the cell-cell communication of other bacteria. This process involves the AI-2-regulated lsr operon, comprised of the Lsr transport system that facilitates uptake of the signal, a kinase that phosphorylates the signal to phospho-DPD (P-DPD), and enzymes (like LsrG) that are responsible for processing the phosphorylated signal. Because P-DPD is the intracellular inducer of the lsr operon, enzymes involved in P-DPD processing impact the levels of Lsr expression. Here we show that LsrG catalyzes isomerization of P-DPD into 3,4,4-trihydroxy-2-pentanone-5-phosphate. We present the crystal structure of LsrG, identify potential catalytic residues, and determine which of these residues affects P-DPD processing in vivo and in vitro. We also show that an lsrG deletion mutant accumulates at least 10 times more P-DPD than wild type cells. Consistent with this result, we find that the lsrG mutant has increased expression of the lsr operon and an altered profile of AI-2 accumulation and removal. Understanding of the biochemical mechanisms employed by bacteria to quench signaling of other species can be of great utility in the development of therapies to control bacterial behavior

    The representation of solar cycle signals in stratospheric ozone – Part 1: A comparison of satellite observations

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    Changes in incoming solar ultraviolet radiation over the 11-year solar cycle affect stratospheric ozone abundances. It is important to quantify the magnitude, structure, and seasonality of the associated solar-ozone response (SOR) to understand the impact of the 11-year solar cycle on climate. Part 1 of this two-part study uses multiple linear regression analysis to extract the SOR in a number of recently updated satellite ozone datasets covering different periods within the epoch 1970 to 2013. The annual mean SOR in the updated version 7.0 (v7.0) Stratospheric Aerosol and Gas Experiment (SAGE) II number density dataset (1984–2004) is very consistent with that found in the previous v6.2. In contrast, we find a substantial decrease in the magnitude of the SOR in the tropical upper stratosphere in the SAGE II v7.0 mixing ratio dataset (∼ 1 %) compared to the v6.2 (∼ 4 %). This difference is shown to be largely attributable to the change in the independent stratospheric temperature dataset used to convert SAGE II ozone number densities to mixing ratios. Since these temperature records contain substantial uncertainties, we suggest that datasets based on SAGE II number densities are currently most reliable for evaluating the SOR. We further analyse three extended ozone datasets that combine SAGE II v7.0 number densities with more recent GOMOS (Global Ozone Monitoring by Occultation of Stars) or OSIRIS (Optical Spectrograph and Infrared Imager System) measurements. The extended SAGE–OSIRIS dataset (1984–2013) shows a smaller and less statistically significant SOR across much of the tropical upper stratosphere compared to the SAGE II data alone. In contrast, the two SAGE–GOMOS datasets (1984–2011) show SORs that are in closer agreement with the original SAGE II data and therefore appear to provide a more reliable estimate of the SOR. We also analyse the SOR in the recent Solar Backscatter Ultraviolet Instrument (SBUV) Merged Ozone Dataset (SBUVMOD) version 8.6 (VN8.6) (1970–2012) and SBUV Merged Cohesive VN8.6 (1978–2012) datasets and compare them to the previous SBUVMOD VN8.0 (1970–2009). Over their full lengths, the three records generally agree in terms of the broad magnitude and structure of the annual mean SOR. The main difference is that SBUVMOD VN8.6 shows a smaller and less significant SOR in the tropical upper stratosphere and therefore more closely resembles the SAGE II v7.0 mixing ratio data than does the SBUV Merged Cohesive VN8.6, which has a more continuous SOR of ∼ 2 % in this region. The sparse spatial and temporal sampling of limb satellite instruments prohibits the extraction of sub-annual variations in the SOR from SAGE-based datasets. However, the SBUVMOD VN8.6 dataset suggests substantial month-to-month variations in the SOR, particularly in the winter extratropics, which may be important for the proposed high-latitude dynamical response to the solar cycle. Overall, the results highlight substantial uncertainties in the magnitude and structure of the observed SOR from different satellite records. The implications of these uncertainties for understanding and modelling the effects of solar variability on climate should be explored

    Theory-Based Design and Development of a Socially Connected, Gamified Mobile App for Men About Breastfeeding (Milk Man)

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    BACKGROUND: Despite evidence of the benefits of breastfeeding, <15% of Australian babies are exclusively breastfed to the recommended 6 months. The support of the father is one of the most important factors in breastfeeding success, and targeting breastfeeding interventions to the father has been a successful strategy in previous research. Mobile technology offers unique opportunities to engage and reach populations to enhance health literacy and healthy behavior. OBJECTIVE: The objective of our study was to use previous research, formative evaluation, and behavior change theory to develop the first evidence-based breastfeeding app targeted at men. We designed the app to provide men with social support and information aiming to increase the support men can offer their breastfeeding partners. METHODS: We used social cognitive theory to design and develop the Milk Man app through stages of formative research, testing, and iteration. We held focus groups with new and expectant fathers (n=18), as well as health professionals (n=16), and used qualitative data to inform the design and development of the app. We tested a prototype with fathers (n=4) via a think-aloud study and the completion of the Mobile Application Rating Scale (MARS).RESULTS: Fathers and health professionals provided input through the focus groups that informed the app development. The think-aloud walkthroughs identified 6 areas of functionality and usability to be addressed, including the addition of a tutorial, increased size of text and icons, and greater personalization. Testers rated the app highly, and the average MARS score for the app was 4.3 out of 5. CONCLUSIONS: To our knowledge, Milk Man is the first breastfeeding app targeted specifically at men. The development of Milk Man followed a best practice approach, including the involvement of a multidisciplinary team and grounding in behavior change theory. It tested well with end users during development. Milk Man is currently being trialed as part of the Parent Infant Feeding Initiative (ACTRN12614000605695)

    Potential and challenges in collecting social and behavioral data on adolescent alcohol norms: Comparing respondent-driven sampling and web-based respondent-driven sampling

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    Background: Respondent-driven sampling (RDS) is a method successfully used to research hard-to-access populations. Few studies have explored the use of the Internet and social media with RDS, known as Web-based RDS (WebRDS). This study explored the use of combining both "traditional" RDS and WebRDS to examine the influences on adolescent alcohol use. Objective: This paper reports on the recruitment processes and the challenges and enablers of both RDS and WebRDS. It details comparative recruitment data and provides a summary of the utility of both methods for recruiting adolescents to participate in an online survey investigating youth alcohol norms. Methods: Process evaluation data collected from research staff throughout the study were used to assess the challenges and solutions of RDS and WebRDS. Pearson chi-square test (Fisher's exact test if applicable) was used to compare the differences in sociodemographics and drinking behavior between data collected by RDS and WebRDS. Results: Of the total sample (N=1012), 232 adolescents were recruited by RDS and 780 by WebRDS. A significantly larger proportion of Aboriginal or Torres Strait Islander (P&lt;.001) participants who spoke English as their main language at home (P=.03), and of middle and lower socioeconomic status (P&lt;.001) was found in the RDS sample. The RDS sample was also found to have a higher occurrence of past 7-day drinking (P&lt;.001) and past 7-day risky drinking (P=.004). No significant differences in gender, age, past month alcohol use, and lifetime alcohol use were observed between the RDS and WebRDS samples. This study revealed RDS and WebRDS used similar lengths of chains for recruiting participants; however, WebRDS conducted a faster rate of recruitment at a lower average cost per participant compared to RDS. Conclusions: Using WebRDS resulted in significant improvements in the recruitment rate and was a more effective and efficient use of resources than the traditional RDS method. However, WebRDS resulted in partially different sample characteristics to traditional RDS. This potential effect should be considered when selecting the most appropriate data collection method

    Space Station Engineering Design Issues

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    Space Station Freedom topics addressed include: general design issues; issues related to utilization and operations; issues related to systems requirements and design; and management issues relevant to design

    Reviews

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    The following publications have been reviewed by the mentioned authors;Taste by Stephen Bayley, reviewed by Stephen R. BlundellDesign and Technology by A. Yarwood and A. H. Orme, reviewed by David JonesAnimal Forms by Nigel Billington and John Jeffrey, reviewed by Lesley LordTechnical Graphics Book 1 by A. Bedford and K. Pyne, reviewed by David JonesScrewcutting in the Lathe by Martin Cleeve, reviewed by David JonesUnderstanding Industry by Alasdair Hogarth, reviewed by Iolo RobertsCase in Hand by Alun Phillips and Geoffrey Stuttard, reviewed by Iolo RobertsGood Practice in Industrial Education by Gordon J. H. Vincent, reviewed by Iolo RobertsStarting Technology by G. Mills and J. Aitken, reviewed by Keith SimmondsDrawing and Painting: A Complete Study Course by Elva Bett, reviewed by John LancasterEarthworks as Sculpture by Peter Jobling, reviewed by Francis CelonaDesign Policy: The Proceedings of an International Conference held at the Royal College of Art, London, 20-23 July 1982. Design and Society, Design and Industry, Design Theory and Practice, Design Evaluation, Design Education, Design and Information Technology reviewed by Bernard MyersAn Introduction to Graphic Design by J. Park, R. De Silva, F. Thomson and C. Tudor, reviewed by F. B. Maycoc
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