503 research outputs found
Leaf Anatomy and CO2 Recycling During Crassulacean Acid Metabolism in Twelve Epiphytic Species of Tillandsia (Bromeliaceae)
This is the publisher's official version. It is also available electronically from: http://www.jstor.org/stable/2995609.The relationship between leaf anatomy, specifically the percent of leaf volume occupied by waterstorage
parenchyma (hydrenchyma), and the contribution of respiratory C02 during Crassulacean acid
metabolism (CAM) was investigated in 12 epiphytic species of Tillandsia. It has been postulated that the
hydrenchyma, which contributes to C 0 2 exchange through respiration only, may be causally related to
the recently observed phenomenon of C 0 2 recycling during CAM. Among the 12 species of Tillandsia,
leaves of T. usneoides and T. bergeri exhibited 0% hydrenchyma, while the hydrenchyma in the other
species ranged from 2.9% to 53% of leaf cross-sectional area. Diurnal malate fluctuation and nighttime
atmospheric C 0 2 uptake were measured in at least four individuals of each species. A significant excess
of diurnal malate fluctuation as compared with atmospheric C 0 2 absorbed overnight was observed only
in T. schiedeana. This species had an intermediate proportion (30%) of hydrenchyma in its leaves. Results
of this study do not support the hypothesis that C02 recycling during CAM may reflect respiratory
contributions of C 0 2 from the tissue hydrenchyma
Synthesis and evaluation of thermally-responsive coatings based upon DielsâAlder chemistry and renewable materials
A soybean based coating with thermally responsive DielsâAlder linkages has been prepared following an automotive 2-component formulation. The resulting coatings displayed the capability to be healed following physical deformation by a thermal stimulus, and such a material has significant potential for end users. Various curing agents were employed, and resulted in variation of scratch resistance and re-healablity. Different thermally responsive soybean resins were synthesized to have varying amounts reversible and nonreversible linkages when incorporated into the coating. Additionally, different isocyanates were added at differing ratios of NCO:OH in search of the optimum coating. It was found through the analysis of rehealability, hardness, gloss, and adhesion that the optimal combination was an acetylated resin (no irreversible crosslinks) with 54% reversible DielsâAlder linkages at an NCO:OH ratio of 5:1 using isophorone diiscocyanate. Materials were evaluated via differential scanning calorimetry (DSC), scratch resistance, Koenig hardness, gloss measurements, and topographical analysis
Daily Dietary Intake Patterns Improve after Visiting a Food Pantry among Food-Insecure Rural Midwestern Adults.
Emergency food pantries provide food at no cost to low-resource populations. The purpose of this study was to evaluate single-day dietary intake patterns before and after visiting a food pantry among food-secure and food-insecure pantry clients. This observational cohort study comprised a paired, before-and-after design with a pantry visit as the intervention. Participants (n = 455) completed a demographic and food security assessment, and two 24-h dietary recalls. Adult food security was measured using the U.S. Household Food Security Survey Module. Dietary intake patterns were assessed using Automated Self-Administered 24-h Recall data and classified by Healthy Eating Index (HEI-2010) scores, dietary variety, number of eating occasions, and energy intake. Paired t-tests and Wilcoxon signed-rank tests compared outcomes before and after a pantry visit. Mean dietary variety increased after the pantry visit among both food-secure (p = 0.02) and food-insecure (p \u3c 0.0001) pantry clients. Mean energy intake (p = 0.0003), number of eating occasions (p = 0.004), and HEI-2010 component scores for total fruit (p \u3c 0.001) and whole fruit (p \u3c 0.0003) increased among food-insecure pantry clients only. A pantry visit may improve dietary intake patterns, especially among food-insecure pantry clients
A Strategy for Finding Near Earth Objects with the SDSS Telescope
We present a detailed observational strategy for finding Near Earth Objects
(NEOs) with the Sloan Digital Sky Survey (SDSS) telescope. We investigate
strategies in normal, unbinned mode as well as binning the CCDs 2x2 or 3x3,
which affects the sky coverage rate and the limiting apparent magnitude. We
present results from 1 month, 3 year and 10 year simulations of such surveys.
For each cadence and binning mode, we evaluate the possibility of achieving the
Spaceguard goal of detecting 90% of 1 km NEOs (absolute magnitude H <= 18 for
an albedo of 0.1). We find that an unbinned survey is most effective at
detecting H <= 20 NEOs in our sample. However, a 3x3 binned survey reaches the
Spaceguard Goal after only seven years of operation. As the proposed large
survey telescopes (PanStarss; LSST) are at least 5-10 years from operation, an
SDSS NEO survey could make a significant contribution to the detection and
photometric characterization of the NEO population.Comment: Accepted by AJ -- 12 pages, 11 figure
Implementing telephone triage in general practice: a process evaluation of a cluster randomised controlled trial
Background: Telephone triage represents one strategy to manage demand for face-to-face GP appointments in primary care. However, limited evidence exists of the challenges GP practices face in implementing telephone triage. We conducted a qualitative process evaluation alongside a UK-based cluster randomised trial (ESTEEM) which compared the impact of GP-led and nurse-led telephone triage with usual care on primary care workload, cost, patient experience, and safety for patients requesting a same-day GP consultation. The aim of the process study was to provide insights into the observed effects of the ESTEEM trial from the perspectives of staff and patients, and to specify the circumstances under which triage is likely to be successfully implemented. Here we report perspectives of staff. Methods: The intervention comprised implementation of either GP-led or nurse-led telephone triage for a period of 2-3 months. A qualitative evaluation was conducted using staff interviews recruited from eight general practices (4 GP triage, 4 Nurse triage) in the UK, implementing triage as part of the ESTEEM trial. Qualitative interviews were undertaken with 44 staff members in GP triage and nurse triage practices (16 GPs, 8 nurses, 7 practice managers, 13 administrative staff). Results: Staff reported diverse experiences and perceptions regarding the implementation of telephone triage, its effects on workload, and on the benefits of triage. Such diversity were explained by the different ways triage was organised, the staffing models used to support triage, how the introduction of triage was communicated across practice staff, and by how staff roles were reconfigured as a result of implementing triage. Conclusion: The findings from the process evaluation offer insight into the range of ways GP practices participating in ESTEEM implemented telephone triage, and the circumstances under which telephone triage can be successfully implemented beyond the context of a clinical trial. Staff experiences and perceptions of telephone triage are shaped by the way practices communicate with staff, prepare for and sustain the changes required to implement triage effectively, as well as by existing practice culture, and staff and patient behaviour arising in response to the changes made. Trial registration: Current Controlled Trials ISRCTN20687662. Registered 28 May 2009
Patterns of medication prescription by dementia diagnosis in Australian nursing home residents: a crossâsectional study
© 2019 The Society of Hospital Pharmacists of Australia
This author accepted manuscript is made available following 12 month embargo from date of publication (March 2019) in accordance with the publisherâs archiving policyCurrent information on the patterns of medication use in nursing home residents living with dementia is conflicting. The aim of this study was to investigate medication use and its associations with dementia diagnosis in Australian nursing home residents
Policy Feedback and the Politics of the Affordable Care Act
There is a large body of literature devoted to how âpolicies create politicsâ and how feedback effects from existing policy legacies shape potential reforms in a particular area. Although much of this literature focuses on selfâreinforcing feedback effects that increase support for existing policies over time, Kent Weaver and his colleagues have recently drawn our attention to selfâundermining effects that can gradually weaken support for such policies. The following contribution explores both selfâreinforcing and selfâundermining policy feedback in relationship to the Affordable Care Act, the most important healthâcare reform enacted in the United States since the midâ1960s. More specifically, the paper draws on the concept of policy feedback to reflect on the political fate of the ACA since its adoption in 2010. We argue that, due in part to its sheer complexity and fragmentation, the ACA generates both selfâreinforcing and selfâundermining feedback effects that, depending of the aspect of the legislation at hand, can either facilitate or impede conservative retrenchment and restructuring. Simultaneously, through a discussion of partisan effects that shape Republican behavior in Congress, we acknowledge the limits of policy feedback in the explanation of policy stability and change
Comparative genomics of isolates of a pseudomonas aeruginosa epidemic strain associated with chronic lung infections of cystic fibrosis patients
Pseudomonas aeruginosa is the main cause of fatal chronic lung infections among individuals suffering from cystic fibrosis (CF). During the past 15 years, particularly aggressive strains transmitted among CF patients have been identified, initially in Europe and more recently in Canada. The aim of this study was to generate high-quality genome sequences for 7 isolates of the Liverpool epidemic strain (LES) from the United Kingdom and Canada representing different virulence characteristics in order to: (1) associate comparative genomics results with virulence factor variability and (2) identify genomic and/or phenotypic divergence between the two geographical locations. We performed phenotypic characterization of pyoverdine, pyocyanin, motility, biofilm formation, and proteolytic activity. We also assessed the degree of virulence using the Dictyostelium discoideum amoeba model. Comparative genomics analysis revealed at least one large deletion (40-50 kb) in 6 out of the 7 isolates compared to the reference genome of LESB58. These deletions correspond to prophages, which are known to increase the competitiveness of LESB58 in chronic lung infection. We also identified 308 non-synonymous polymorphisms, of which 28 were associated with virulence determinants and 52 with regulatory proteins. At the phenotypic level, isolates showed extensive variability in production of pyocyanin, pyoverdine, proteases and biofilm as well as in swimming motility, while being predominantly avirulent in the amoeba model. Isolates from the two continents were phylogenetically and phenotypically undistinguishable. Most regulatory mutations were isolate-specific and 29% of them were predicted to have high functional impact. Therefore, polymorphism in regulatory genes is likely to be an important basis for phenotypic diversity among LES isolates, which in turn might contribute to this strain's adaptability to varying conditions in the CF lung
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Convective-scale perturbation growth across the spectrum of convective regimes
Convection-permitting ensembles have led to improved forecasts of many atmospheric phenomena. However, to fully utilize these forecasts the dependence of predictability on synoptic conditions needs to be understood. In this study, convective regimes are diagnosed based on a convective timescale which identifies the degree to which convection is in equilibrium with the large-scale forcing. Six convective cases are examined in a convection-permitting ensemble constructed using the Met Office Unified Model. The
ensemble members were generated using small-amplitude buoyancy perturbations added into the boundary layer, which can be considered to represent turbulent fluctuations close to the gridscale. Perturbation growth is shown to occur on different scales with an order of magnitude difference between the regimes (O(1 km) for cases closer to non-equilibrium convection and O(10 km) for cases closer to equilibrium convection). This difference reflects the fact that cell locations are essentially random in the equilibrium events after the first 12 h of the forecast, indicating a more rapid upscale perturbation growth compared to the non-equilibrium events. Furthermore, large temporal
variability is exhibited in all perturbation growth diagnostics for the nonequilibrium regime. Two boundary condition driven cases are also considered and show similar characteristics to the non-equilibrium cases, implying that caution is needed to interpret the timescale when initiation is not within the domain. Further understanding of perturbation growth within the different regimes could lead to a better understanding of where ensemble design improvements can be made beyond increasing the model resolution and could improve interpretation of forecasts
The gene-rich genome of the scallop Pecten maximus.
BACKGROUND: The king scallop, Pecten maximus, is distributed in shallow waters along the Atlantic coast of Europe. It forms the basis of a valuable commercial fishery and plays a key role in coastal ecosystems and food webs. Like other filter feeding bivalves it can accumulate potent phytotoxins, to which it has evolved some immunity. The molecular origins of this immunity are of interest to evolutionary biologists, pharmaceutical companies, and fisheries management. FINDINGS: Here we report the genome assembly of this species, conducted as part of the Wellcome Sanger 25 Genomes Project. This genome was assembled from PacBio reads and scaffolded with 10X Chromium and Hi-C data. Its 3,983 scaffolds have an N50 of 44.8 Mb (longest scaffold 60.1 Mb), with 92% of the assembly sequence contained in 19 scaffolds, corresponding to the 19 chromosomes found in this species. The total assembly spans 918.3 Mb and is the best-scaffolded marine bivalve genome published to date, exhibiting 95.5% recovery of the metazoan BUSCO set. Gene annotation resulted in 67,741 gene models. Analysis of gene content revealed large numbers of gene duplicates, as previously seen in bivalves, with little gene loss, in comparison with the sequenced genomes of other marine bivalve species. CONCLUSIONS: The genome assembly of P. maximus and its annotated gene set provide a high-quality platform for studies on such disparate topics as shell biomineralization, pigmentation, vision, and resistance to algal toxins. As a result of our findings we highlight the sodium channel gene Nav1, known to confer resistance to saxitoxin and tetrodotoxin, as a candidate for further studies investigating immunity to domoic acid
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