10,249 research outputs found

    Towards understanding the variability in biospheric CO2 fluxes:Using FTIR spectrometry and a chemical transport model to investigate the sources and sinks of carbonyl sulfide and its link to CO2

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    Understanding carbon dioxide (CO2) biospheric processes is of great importance because the terrestrial exchange drives the seasonal and interannual variability of CO2 in the atmosphere. Atmospheric inversions based on CO2 concentration measurements alone can only determine net biosphere fluxes, but not differentiate between photosynthesis (uptake) and respiration (production). Carbonyl sulfide (OCS) could provide an important additional constraint: it is also taken up by plants during photosynthesis but not emitted during respiration, and therefore is a potential means to differentiate between these processes. Solar absorption Fourier Transform InfraRed (FTIR) spectrometry allows for the retrievals of the atmospheric concentrations of both CO2 and OCS from measured solar absorption spectra. Here, we investigate co-located and quasi-simultaneous FTIR measurements of OCS and CO2 performed at five selected sites located in the Northern Hemisphere. These measurements are compared to simulations of OCS and CO2 using a chemical transport model (GEOS-Chem). The coupled biospheric fluxes of OCS and CO2 from the simple biosphere model (SiB) are used in the study. The CO2 simulation with SiB fluxes agrees with the measurements well, while the OCS simulation reproduced a weaker drawdown than FTIR measurements at selected sites, and a smaller latitudinal gradient in the Northern Hemisphere during growing season when comparing with HIPPO (HIAPER Pole-to-Pole Observations) data spanning both hemispheres. An offset in the timing of the seasonal cycle minimum between SiB simulation and measurements is also seen. Using OCS as a photosynthesis proxy can help to understand how the biospheric processes are reproduced in models and to further understand the carbon cycle in the real world

    Comparative cytogenetic analysis between Lonchorhina aurita and Trachops cirrhosus (Chiroptera, Phyllostomidae)

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    Phyllostomidae comprises the most diverse family of neotropical bats, its wide range of morphological features leading to uncertainty regarding phylogenetic relationships. Seeing that cytogenetics is one of the fields capable of providing support for currently adopted classifications through the use of several markers, a comparative analysis between two Phyllostomidae species was undertaken in the present study, with a view to supplying datasets for the further establishment of Phyllostomidae evolutionary relationships. Karyotypes of Lonchorhina aurita (2n = 32; FN = 60) and Trachops cirrhosus (2n = 30; FN = 56) were analyzed by G- and C-banding, silver nitrate staining (Ag-NOR) and base-specific fluorochromes. Chromosomal data obtained for both species are in agreement with those previously described, except for X chromosome morphology in T. cirrhosus, hence indicating chromosomal geographical variation in this species. A comparison of G-banding permitted the identification of homeologies in nearly all the chromosomes. Furthermore, C-banding and Ag-NOR patterns were comparable to what has already been observed in the family. In both species CMA3 /DA/DAPI staining revealed an R-banding-like pattern with CMA 3 , whereas DAPI showed uniform staining in all the chromosomes. Fluorochrome staining patterns for pericentromeric constitutive heterochromatin (CH) regions, as well as for nucleolar organizing regions (NORs), indicated heterogeneity regarding these sequences among Phyllostomidae species

    Can majority support save an endangered language? A case study of language attitudes in Guernsey

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    Many studies of minority language revitalisation focus on the attitudes and perceptions of minorities, but not on those of majority group members. This paper discusses the implications of these issues, and presents research into majority andf minority attitudes towards the endangered indigenous vernacular of Guernsey, Channel Islands. The research used a multi-method approach (questionnaire and interview) to obtain attitudinal data from a representative sample of the population that included politicians and civil servants (209 participants). The findings suggested a shift in language ideology away from the post-second world war ‘culture of modernisation’ and monolingual ideal, towards recognition of the value of a bi/trilingual linguistic heritage. Public opinion in Guernsey now seems to support the maintenance of the indigenous language variety, which has led to a degree of official support. The paper then discusses to what extent this ‘attitude shift’ is reflected in linguistic behaviour and in concrete language planning measures

    Low Mass Stars and Brown Dwarfs in Praesepe

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    Presented are the results of a large and deep optical-near-infrared multi-epoch survey of the Praesepe open star cluster using data from the UKIDSS Galactic Clusters Survey. Multiple colour magnitude diagrams were used to select potential members and proper motions were used to assign levels of membership probability. From our sample, 145 objects were designated as high probability members (p >= 0.6) with most of these having been found by previous surveys although 14 new cluster members are also identified. Our membership assignment is restricted to the bright sample of objects (Z < 18). From the fainter sample, 39 candidates were found from an examination of multiple colour magnitude plots. Of these, 2 have small but significant membership probabilities. Finally, using theoretical models, cluster luminosity and mass functions were plotted with the later being fitted with a power law of alpha = 1.11 +/- 0.37 for the mass range 0.6 to 0.125 Msun and an assumed cluster age of 500 Myrs in the UKIDSS Z photometric band. Likewise taking an assumed cluster age of 1 Gyr we find alpha = 1.10 +/- 0.37. Similar values were also found for the J and K bands. These results compare favourably with the result of Kraus & Hillenbrand (2007) (alpha = 1.4 +/- 0.2) but are significantly lower than that of the more recent study conducted by Boudreault et al. (2009) (alpha = 1.8 +/- 0.1).Comment: 21 pages, 11 figures, 3 tables and 4 appendices. Accepted for publication in MNRAS, corrected a missing referenc

    Detection of Cosmic Microwave Background Structure in a Second Field with the Cosmic Anisotropy Telescope

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    We describe observations at frequencies near 15 GHz of the second 2x2 degree field imaged with the Cambridge Cosmic Anisotropy Telescope (CAT). After the removal of discrete radio sources, structure is detected in the images on characteristic scales of about half a degree, corresponding to spherical harmonic multipoles in the approximate range l= 330--680. A Bayesian analysis confirms that the signal arises predominantly from the cosmic microwave background (CMB) radiation for multipoles in the lower half of this range; the average broad-band power in a bin with centroid l=422 (theta = 51') is estimated to be Delta_T/T=2.1^{+0.4}_{-0.5} x 10^{-5}. For multipoles centred on l=615 (theta =35'), we find contamination from Galactic emission is significant, and constrain the CMB contribution to the measured power in this bin to be Delta_T/T <2.0 x 10^{-5} (1-sigma upper limit). These new results are consistent with the first detection made by CAT in a completely different area of sky. Together with data from other experiments, this new CAT detection adds weight to earlier evidence from CAT for a downturn in the CMB power spectrum on scales smaller than 1 degree. Improved limits on the values of H_0 and Omega are determined using the new CAT data.Comment: 5 pages, 5 figures (gif), submitted to MNRA

    Fate of drugs during wastewater treatment

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    This is the post-print version of the final paper published in TrAC Trends in Analytical Chemistry. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2013 Elsevier B.V.Recent trends in the determination of pharmaceutical drugs in wastewaters focus on the development of rapid multi-residue methods. This review addresses recent analytical trends in drug determination in environmental matrices used to facilitate fate studies. Analytical requirements for further fate evaluation and tertiary process selection and optimization are also discussed.EPSRC, Northumbrian Water, Anglian Water, Severn Trent Water, Yorkshire Water, and United Utilities

    A novel system for spatial and temporal imaging of intrinsic plant water use efficiency

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    Instrumentation and methods for rapid screening and selection of plants with improved water use efficiency are essential to address current issues of global food and fuel security. A new imaging system that combines chlorophyll fluorescence and thermal imaging has been developed to generate images of assimilation rate (A), stomatal conductance (gs), and intrinsic water use efficiency (WUEi) from whole plants or leaves under controlled environmental conditions. This is the first demonstration of the production of images of WUEi and the first to determine images of gs from themography at the whole-plant scale. Data are presented illustrating the use of this system for rapidly and non-destructively screening plants for alterations in WUEi by comparing Arabidopsis thaliana mutants (OST1-1) that have altered WUEi driven by open stomata, with wild-type plants. This novel instrument not only provides the potential to monitor multiple plants simultaneously, but enables intra- and interspecies variation to be taken into account both spatially and temporally. The ability to measure A, gs, and WUEi progressively was developed to facilitate and encourage the development of new dynamic protocols. Images illustrating the instrument's dynamic capabilities are demonstrated by analysing plant responses to changing photosynthetic photon flux density (PPFD). Applications of this system will augment the research community's need for novel screening methods to identify rapidly novel lines, cultivars, or species with improved A and WUEi in order to meet the current demands on modern agriculture and food production. © The Author 2013. Published by Oxford University Press on behalf of the Society for Experimental Biology

    Darboux transformations of Jacobi matrices and Pad\'e approximation

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    Let J be a monic Jacobi matrix associated with the Cauchy transform F of a probability measure. We construct a pair of the lower and upper triangular block matrices L and U such that J=LU and the matrix J_c=UL is a monic generalized Jacobi matrix associated with the function F_c(z)=zF(z)+1. It turns out that the Christoffel transformation J_c of a bounded monic Jacobi matrix J can be unbounded. This phenomenon is shown to be related to the effect of accumulating at infinity of the poles of the Pad\'e approximants of the function F_c although F_c is holomorphic at infinity. The case of the UL-factorization of J is considered as well.Comment: 28 pages (some typos are corrected

    Association of Chartered Physiotherapists in Respiratory Care scoping review: Post-operative physiotherapy management in upper gastrointestinal (GI) surgery

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    Objective This scoping review will identify and synthesise the available evidence for post-operative physiotherapy following upper GI surgery, in order to identify gaps in the literature, inform evidence-based practice and contribute towards guidelines and/or policy development. Introduction Physiotherapy management following thoracic, cardiac and upper gastrointestinal surgery has been identified as one of the five key priorities for review by the Association of Chartered Physiotherapists in Respiratory Care (ACPRC) editorial board. Previously, systematic reviews have been published with a focus on one type of physiotherapy treatment. The aim of this scoping review was to identify all types of post-operative physiotherapy following upper GI surgery research to provide a comprehensive review of available evidence. Inclusion criteria Studies with adult patients undergoing upper GI surgery and published between 2015 and 2020 were included. The surgical procedure included required post-operative physiotherapy intervention as part of the recovery process. The context was in-patient, hospital-based surgery. Physiotherapy intervention prior to admission (such as pre-habilitation), and intervention after hospital discharge, for example, out-patient follow up were excluded. Research from any country of origin and any type of healthcare system was included. Methods The search strategy was agreed by the scoping team and searches were undertaken of PEDro, CINAHL, EMBASE, MEDLINE, PubMed, Google Scholar and the Clinical Trials Registry. Exclusion criteria included any articles not written in English. All identified citations were uploaded into web-based Endnote. Articles were screened against title and abstract by one reviewer, and full text articles were appraised by two reviewers. Data extraction included the aim of the study, design/methodology, sample details (number of participants, mean age, gender ratio), comparison group details, outcome measures, and key findings relevant to the scoping review questions. Quality was assessed using the relevant Critical Appraisal Skills Programme (CASP) or Joanna Briggs Institute (JBI) tools dependent on study methodology. Results Eleven studies were identified for inclusion of which there were three randomised control trials (RCT), four cohort studies, one systematic review, one cross sectional study, one narrative review and one survey. No qualitative studies were found. Four studies considered the role of adjuncts (incentive spirometry and inspiratory muscle training). Five studies investigated ambulation or early mobilisation post-surgery, one study looked at the role of pre-operative education and one study looked at current practise. 57 physiotherapists were surveyed, 1,384 participants were included in studies and 37 papers were included in reviews. The studies found that early and intensive mobilisation as part of an ERAS programme showed a statistically significant reduction in length of stay (LOS) and post-operative pulmonary complications (PPCs). Reported physiotherapy interventions are in line with current best practice guidelines. IMT and IS continue to show positive results in the literature in particular in the older and high-risk patient. Pre-operative assessment and education should be considered in patients undergoing upper abdominal GI surgery however screening tools for prioritisation are not yet established. The quality of the research was generally good; however, sample sizes were small and often underpowered. Conclusions This scoping review has demonstrated that current evidence supports post-operative physiotherapy intervention in people who undergo upper GI surgery. Future research should aim to determine the role of pre-operative physiotherapy, clarify the impact of breathing exercise protocols and expand the diversity of methodologies to include more qualitative research

    76 T dwarfs from the UKIDSS LAS : benchmarks, kinematics and an updated space density

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    We report the discovery of 76 new T dwarfs from the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). Near-infrared broad- and narrow-band photometry and spectroscopy are presented for the new objects, along with Wide-field Infrared Survey Explorer (WISE) and warm-Spitzer photometry. Proper motions for 128 UKIDSS T dwarfs are presented from a new two epoch LAS proper motion catalogue. We use these motions to identify two new benchmark systems: LHS 6176AB, a T8p+M4 pair and HD 118865AB, a T5.5+F8 pair. Using age constraints from the primaries and evolutionary models to constrain the radii, we have estimated their physical properties from their bolometric luminosity. We compare the colours and properties of known benchmark T dwarfs to the latest model atmospheres and draw two principal conclusions. First, it appears that the H - [4.5] and J - W2 colours are more sensitive to metallicity than has previously been recognized, such that differences in metallicity may dominate over differences in T-eff when considering relative properties of cool objects using these colours. Secondly, the previously noted apparent dominance of young objects in the late-T dwarf sample is no longer apparent when using the new model grids and the expanded sample of late-T dwarfs and benchmarks. This is supported by the apparently similar distribution of late-T dwarfs and earlier type T dwarfs on reduced proper motion diagrams that we present. Finally, we present updated space densities for the late-T dwarfs, and compare our values to simulation predictions and those from WISE.Peer reviewe
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