38 research outputs found

    Comparative study of in situ N2 rotational Raman spectroscopy methods for probing energy thermalisation processes during spin-exchange optical pumping

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    Spin-exchange optical pumping (SEOP) has been widely used to produce enhancements in nuclear spin polarisation for hyperpolarised noble gases. However, some key fundamental physical processes underlying SEOP remain poorly understood, particularly in regards to how pump laser energy absorbed during SEOP is thermalised, distributed and dissipated. This study uses in situ ultra-low frequency Raman spectroscopy to probe rotational temperatures of nitrogen buffer gas during optical pumping under conditions of high resonant laser flux and binary Xe/N2 gas mixtures. We compare two methods of collecting the Raman scattering signal from the SEOP cell: a conventional orthogonal arrangement combining intrinsic spatial filtering with the utilisation of the internal baffles of the Raman spectrometer, eliminating probe laser light and Rayleigh scattering, versus a new in-line modular design that uses ultra-narrowband notch filters to remove such unwanted contributions. We report a ~23-fold improvement in detection sensitivity using the in-line module, which leads to faster data acquisition and more accurate real-time monitoring of energy transport processes during optical pumping. The utility of this approach is demonstrated via measurements of the local internal gas temperature (which can greatly exceed the externally measured temperature) as a function of incident laser power and position within the cell

    Big Data Challenges in Climate Science: Improving the Next-Generation Cyberinfrastructure

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    The knowledge we gain from research in climate science depends on the generation, dissemination, and analysis of high-quality data. This work comprises technical practice as well as social practice, both of which are distinguished by their massive scale and global reach. As a result, the amount of data involved in climate research is growing at an unprecedented rate. Climate model intercomparison (CMIP) experiments, the integration of observational data and climate reanalysis data with climate model outputs, as seen in the Obs4MIPs, Ana4MIPs, and CREATE-IP activities, and the collaborative work of the Intergovernmental Panel on Climate Change (IPCC) provide examples of the types of activities that increasingly require an improved cyberinfrastructure for dealing with large amounts of critical scientific data. This paper provides an overview of some of climate science's big data problems and the technical solutions being developed to advance data publication, climate analytics as a service, and interoperability within the Earth System Grid Federation (ESGF), the primary cyberinfrastructure currently supporting global climate research activities

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    Targeting TOR signaling for enhanced lipid productivity in algae

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    International audienceMicroalgae can produce large quantities of triacylglycerols (TAGs) and other neutral lipids that are suitable for making biofuels and as feedstocks for green chemistry. However, TAGs accumulate under stress conditions that also stop growth, leading to a trade-off between biomass production and TAG yield. Recently, in the model marine diatom Phaeodactylum tricornutum it was shown that inhibition of the target of rapamycin (TOR) kinase boosts lipid productivity by promoting TAG production without stopping growth. We believe that basic knowledge in this emerging field is required to develop innovative strategies to improve neutral lipid accumulation in oleaginous microalgae. In this minireview, we discuss current research on the TOR signaling pathway with a focus on its control on lipid homeostasis. We first provide an overview of the well characterized roles of TOR in mammalian lipogenesis, adipogenesis and lipolysis. We then present evidence of a role for TOR in controlling TAG accumulation in microalgae, and draw parallels between the situation in animals, plants and microalgae to propose a model of TOR signaling for TAG accumulation in microalgae

    Program of Integrated Care for Patients with Chronic Obstructive Pulmonary Disease and Multiple Comorbidities (PIC COPD<sup>+</sup>):a randomised controlled trial

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    We sought to evaluate the effectiveness of a multi-component, case manager-led exacerbation prevention/management model for reducing emergency department visits. Secondary outcomes included hospitalisation, mortality, health-related quality of life, chronic obstructive pulmonary disease (COPD) severity, COPD self-efficacy, anxiety and depression.Two-centre randomised controlled trial recruiting patients with ≥2 prognostically important COPD-associated comorbidities. We compared our multi-component intervention including individualised care/action plans and telephone consults (12-weekly then 9-monthly) with usual care (both groups). We used zero-inflated Poisson models to examine emergency department visits and hospitalisation; Cox proportional hazard model for mortality.We randomised 470 participants (236 intervention, 234 control). There were no differences in number of emergency department visits or hospital admissions between groups. We detected difference in emergency department visit risk, for those that visited the emergency department, favouring the intervention (RR 0.74, 95% CI 0.63–0.86). Similarly, risk of hospital admission was lower in the intervention group for those requiring hospital admission (RR 0.69, 95% CI 0.54–0.88). Fewer intervention patients died (21 versus 36) (HR 0.56, 95% CI 0.32–0.95). No differences were detected in other secondary outcomes.Our multi-component, case manager-led exacerbation prevention/management model resulted in no difference in emergency department visits, hospital admissions and other secondary outcomes. Estimated risk of death (intervention) was nearly half that of the control.</jats:p

    Enabling Reanalysis Research Using the Collaborative Reanalysis Technical Environment (CREATE)

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    Modern atmospheric and oceanic reanalysis are valuable assets for atmospheric research and climate monitoring (Kalnay et al. 1996). Now that most reanalysis records are more than 36 years long, the data have become more useful for climate modeling research (Dole et al. 2008). For investigators who need to use multiple reanalysis, a common challenge is that the data are distributed at various sites and often in different formats. The NASA CREATE system provides access to the data in one location in a standard format (one variable per file and standardized metadata in the CMIP5 style; see Table 1 for a list of the key acronyms used in this paper). The collection includes monthly and 6-hourly data from the seven major atmospheric reanalysis: CFSR (Saha et al. 2010), ERA-Interim (Dee et al. 2011), MERRA (Rienecker et al. 2011), MERRA-2 (Gelaro et al. 2017), JRA-25 (Onogi et al. 2007), JRA-55 (Kobayashi et al. 2014), and 20CRv2c (Compo et al. 2011). An ancillary portion of CREATE includes eight ocean reanalysis: NCEP CFSR, CMCC C-GLORSv5 (Storto et al. 2016), ECMWF ORAS4 (Balmaseda et al.2013), ECMWF ORAP5.0 (Zuo et al. 2015), University of Hamburg GECCO2 (Khl 2015), GFDL ECDA (Zhang et al. 2007), NOAA GODAS (Saha et al. 2010), and MOVE/MRI.COM-G2i (Toyoda et al. 2016). The ocean state variables were similarly reformatted but were then also regridded onto a common horizontal and vertical grid. This approach facilitated the calculation of an ensemble average and spread that is also published alongside the native gridded data. A third reanalysis product is a global hourly 0.5 land surface air temperature dataset constructed by Wang and Zeng (2013). All three datasets are distributed through the ESGF in a format consistent with the CMIP style described by Cinquini et al. (2014)
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