5,095 research outputs found

    Do body condition and plumage during fuelling predict northwards departure dates of Great Knots Calidris tenuirostris from north-west Australia?

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    It is often assumed that strong selection pressures give rise to trade-offs between body condition and time in long-distance migrating birds. Birds that are 'behind schedule' in fuel deposition or moult should delay departure, and this should result in a negative correlation between initial condition and departure date. We tested this hypothesis in the Great Knot Calidris tenuirostris migrating from north-west Australia to eastern Asia en route to Siberia. Great Knot gain mass and moult into breeding plumage before leaving northern Australia in late March and early April, and fly 5400-6000 km to eastern China and Korea. We radiotracked 27 individuals (17 males and ten females) to determine departure dates; 23 migrated and four remained in Australia. We characterized body condition at capture using body mass, predicted pectoral muscle mass (based on ultrasound estimates of the size of the pectoral muscles) and breeding plumage scores. Residual condition indices were uncorrelated, indicating that at the individual level, variation in one fuelling component was not strongly associated with variation in the other components. Birds that did not depart had lower residual body mass and breeding plumage indices than those that did migrate; these four birds may have been subadults. Neither sex, size nor the condition indices explained variation in departure date of migrants. Reasons for this are explored. Departure dates for northward migrating waders indicate that the migration window (span over which birds depart) decreases with proximity to the northern breeding grounds. We suggest that migration schedules become tighter as birds get nearer to the breeding grounds. Thus the lack of a relationship between condition and departure date in Great Knots may reflect the fact that the departure episode under study is the first one in sequence and is still 4-8 weeks before breeding

    Searching for wheat resistance to aphids and wheat bulb fly in the historical Watkins and Gediflux wheat collections

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    Insect pests can reduce wheat yield by direct feeding and transmission of plant viruses. Here we report results from laboratory and field phenotyping studies on a wide range of wheat, including landraces from the Watkins collection deriving from before the green revolution, more modern cultivars from the Gediflux collection (north-western Europe) and modern UK Elite varieties, for resistance to the bird cherry-oat aphid, Rhopalosiphum padi (Homoptera: Aphididae) and the English grain aphid, Sitobion avenae (Homoptera: Aphididae). A total of 338 lines were screened for R. padi and 340 lines for S. avenae. Field trials were also conducted on 122 Watkins lines to identify wheat bulb fly, Delia coarctata, preference on these landraces. Considerable variation was shown in insect performance among and within different wheat collections, with reduced susceptibility in a number of varieties, but phenotyping did not identify strong resistance to aphids or wheat bulb fly. Field trials showed within collection differences in aphid performance, with fewer aphids populating lines from the Watkins collection. This differs from development data in laboratory bioassays and suggests that there is a pre-alighting cue deterring aphid settlement and demonstrates differences in aphid preference and performance on older plants in the field compared with seedlings in the laboratory, highlighting the need for phenotyping for aphid resistance at different plant growth stages. No association was identified between performance of the different insect species on individual varieties, potentially suggesting different nutritional requirements or resistance mechanisms

    Hypophosphataemia after intravenous iron therapy with ferric carboxymaltose—Real world experience from a tertiary centre in the UK

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    Background: Iron deficiency is the most common global cause of anaemia. Intravenous (IV) iron is used to correct iron deficiency anaemia (IDA) where oral iron cannot be used. Despite being effective, certain IV iron formulations cause significant hypophosphataemia. However, current knowledge on the clinical consequences of IV iron‐induced hypophosphataemia is broadly anecdotal or limited to isolated case reports. / Aims: To retrospectively examine the incidence and potential clinical consequences of hypophosphataemia post‐IV ferric carboxymaltose (FCM) in hospitalised patients with IDA (mixed aetiology). / Methods: Data were collected for 162 patients, who received a total of 169 FCM courses during a 2‐year audit period. Outcomes included incidence of moderate/severe hypophosphataemia (serum phosphate <0.65 mmol/L) ≀90 days post‐FCM, changes in alkaline phosphatase, need for phosphate replacement, and length of hospital stay. / Results: The incidence of moderate/severe hypophosphataemia post‐FCM was 33.7%; within this group the rate of severe hypophosphataemia (serum phosphate ≀0.32 mmol/L) was 8.8%. Moderate/severe hypophosphataemia persisted, with 35% of patients having a serum phosphate of <0.65 mmol/L for ≀90 days at the last measurement after IV FCM. Intervention with IV phosphate—an average of 4.4 infusions per person—was required in 29.8% of cases with moderate/severe hypophosphataemia. FCM‐induced moderate/severe hypophosphataemia was associated with a significantly longer hospital stay (P < 0.0035). / Conclusions: Moderate/severe hypophosphataemia is a frequent adverse drug reaction with FCM. In our study, FCM‐induced moderate/severe hypophosphataemia was also persistent, often required treatment, and was associated with longer hospital stay

    Social networks and labour productivity in Europe: An empirical investigation

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    This paper uses firm-level data recorded in the AMADEUS database to investigate the distribution of labour productivity in different European countries. We find that the upper tail of the empirical productivity distributions follows a decaying power-law, whose exponent α\alpha is obtained by a semi-parametric estimation technique recently developed by Clementi et al. (2006). The emergence of "fat tails" in productivity distribution has already been detected in Di Matteo et al. (2005) and explained by means of a model of social network. Here we show that this model is tested on a broader sample of countries having different patterns of social network structure. These different social attitudes, measured using a social capital indicator, reflect in the power-law exponent estimates, verifying in this way the existence of linkages among firms' productivity performance and social network.Comment: LaTeX2e; 18 pages with 3 figures; Journal of Economic Interaction and Coordination, in pres

    Enteral Nutrition in Adult Crohn’s Disease: Toward a Paradigm Shift

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    Medical and surgical treatments for Crohn’s disease are associated with toxic effects. Medical therapy aims for mucosal healing and is achievable with biologics, immunosuppressive therapy, and specialised enteral nutrition, but not with corticosteroids. Sustained remission remains a therapeutic challenge. Enteral nutrition, containing macro- and micro-nutrients, is nutritionally complete, and is provided in powder or liquid form. Enteral nutrition is a low-risk and minimally invasive therapy. It is well-established and recommended as first line induction therapy in paediatric Crohn’s disease with remission rates of up to 80%. Other than in Japan, enteral nutrition is not routinely used in the adult population among Western countries, mainly due to unpalatable formulations which lead to poor compliance. This study aims to offer a comprehensive review of available enteral nutrition formulations and the literature supporting the use and mechanisms of action of enteral nutrition in adult Crohn’s disease patients, in order to support clinicians in real world decision-making when offering/accepting treatment. The mechanisms of actions of enteral feed, including their impact on the gut microbiome, were explored. Barriers to the use of enteral nutrition, such as compliance and the route of administration, were considered. All available enteral preparations have been comprehensively described as a practical guide for clinical use. Likewise, guidelines are reported and discussed

    Clinical and Nutritional Care Pathways of Patients with Malignant Bowel Obstruction: A Retrospective Analysis in a Tertiary UK Center

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    We describe a retrospective cohort study of patients with malignant bowel obstruction to examine their nutritional care pathways between 1.1.16 and 31.12.16 with readmissions until 31.12.17. Data were analyzed by comparing patients who were referred (R) and not referred (NR) for PN. We identified 72 patients with 117 MBO admissions (mean ± SD age:63.1 ± 13.1yrs, 79% female). 24/72 patients were in R group. Predominant primary malignancies were gynaecological and lower-gastrointestinal cancers (76%). 83% patients had metastases (61% sub-diaphragmatically). All patients were at high-risk of malnutrition and baseline mean weight loss was 7%. Discussion of PN at multidisciplinary team meeting (MDT) (22% vs.5%, P = 0.02) and dietetic contact (94% vs. 41%, P < 0.0001) were more likely to occur in the R group. In 13/69 MBO admissions in NR group, reasons for non-referral were unclear. Median baseline and follow-up weight was similar (55–55.8 kg). Overall survival was 4.7 (1.4–15.2)months, with no differences by referral groups. We compared a sub-sample of patients who ‘may have’ required PN (n = 10) vs. those discharged on home PN (n = 10) and found greater survival in the HPN group (323vs.91 day, P < 0.01). Our findings highlight disparity in care pathways suggesting that nutritional care should be integrated into clinical management discussion(s) at MDT to ensure equal access to nutritional services

    On the Nature of Small Planets around the Coolest Kepler Stars

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    We constrain the densities of Earth- to Neptune-size planets around very cool (Te =3660-4660K) Kepler stars by comparing 1202 Keck/HIRES radial velocity measurements of 150 nearby stars to a model based on Kepler candidate planet radii and a power-law mass-radius relation. Our analysis is based on the presumption that the planet populations around the two sets of stars are the same. The model can reproduce the observed distribution of radial velocity variation over a range of parameter values, but, for the expected level of Doppler systematic error, the highest Kolmogorov-Smirnov probabilities occur for a power-law index alpha ~ 4, indicating that rocky-metal planets dominate the planet population in this size range. A single population of gas-rich, low-density planets with alpha = 2 is ruled out unless our Doppler errors are >= 5m/s, i.e., much larger than expected based on observations and stellar chromospheric emission. If small planets are a mix of gamma rocky planets (alpha = 3.85) and 1-gamma gas-rich planets (alpha = 2), then gamma > 0.5 unless Doppler errors are >=4 m/s. Our comparison also suggests that Kepler's detection efficiency relative to ideal calculations is less than unity. One possible source of incompleteness is target stars that are misclassified subgiants or giants, for which the transits of small planets would be impossible to detect. Our results are robust to systematic effects, and plausible errors in the estimated radii of Kepler stars have only moderate impact.Comment: Accepted to the Astrophysical Journa

    Foreground Contamination in Interferometric Measurements of the Redshifted 21 cm Power Spectrum

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    Subtraction of astrophysical foreground contamination from "dirty" sky maps produced by simulated measurements of the Murchison Widefield Array (MWA) has been performed by fitting a 3rd-order polynomial along the spectral dimension of each pixel in the data cubes. The simulations are the first to include the unavoidable instrumental effects of the frequency-dependent primary antenna beams and synthesized array beams. They recover the one-dimensional spherically-binned input redshifted 21 cm power spectrum to within approximately 1% over the scales probed most sensitively by the MWA (0.01 < k < 1 Mpc^-1) and demonstrate that realistic instrumental effects will not mask the EoR signal. We find that the weighting function used to produce the dirty sky maps from the gridded visibility measurements is important to the success of the technique. Uniform weighting of the visibility measurements produces the best results, whereas natural weighting significantly worsens the foreground subtraction by coupling structure in the density of the visibility measurements to spectral structure in the dirty sky map data cube. The extremely dense uv-coverage of the MWA was found to be advantageous for this technique and produced very good results on scales corresponding to |u| < 500 wavelengths in the uv-plane without any selective editing of the uv-coverage.Comment: Replaced with version accepted by ApJ. 19 pages, including 3 figure

    Fermionic counting of RSOS-states and Virasoro character formulas for the unitary minimal series M(\nu,\nu+1). Exact results

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    The Hilbert space of an RSOS-model, introduced by Andrews, Baxter, and Forrester, can be viewed as a space of sequences (paths) {a_0,a_1,...,a_L}, with a_j-integers restricted by 1<=a_j<=\nu, |a_j-a_{j+1}|=1, a_0=s, a_L=r. In this paper we introduce different basis which, as shown here, has the same dimension as that of an RSOS-model. Following McCoy et al, we call this basis -- fermionic (FB). Our first theorem Dim(FB)=Dim(RSOS-basis) can be succinctly expressed in terms of some identities for binomial coefficients. Remarkably, these binomial identities can be q-deformed. Here, we give a simple proof of these q-binomial identities in the spirit of Schur's proof of the Rogers-Ramanujan identities. Notably, the proof involves only the elementary recurrences for the q-binomial coefficients and a few creative observations. Finally, taking the limit L --> \infty in these q-identities, we derive an expression for the character formulas of the unitary minimal series M(\nu,\nu+1) "Bosonic Sum = Fermionic Sum". Here, Bosonic Sum denotes Rocha-Caridi representation (\chi_{r,s=1}^{\nu,\nu+1}(q)) and Fermionic Sum stands for the companion representation recently conjectured by the Stony Brook group.Comment: 33pp, LaTex, BONN-HE-94-04, spelling errors and typos corrected, references added, to appear in Nucl. Phys. B431 (1994

    Colour Gradients and the Colour-Magnitude Relation: Different Properties of Brightest Cluster Galaxies and E/S0 Galaxies in the Sloan Digital Sky Survey

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    We examine the colour-magnitude relation of approximately 5000 Brightest Cluster Galaxies (BCGs) in the Sloan Digital Sky Survey, and compare with non-BCG E/S0 galaxies. The colour-magnitude and colour-sigma (velocity dispersion) relations are flatter in slope (by a factor of about 2) for BCGs than for non-BCG E/S0s, and the BCGs also tend to be redder by 0.01 magnitudes in g-r. We investigate radial colour gradients in both samples, using the ratio of the de Vaucouleurs radii in the g and r bands. We find BCGs have significantly flatter (by 23%) mean colour gradients than other high luminosity E/S0s. In early-type galaxies, the colour gradients are strongest at intermediate luminosities of Mr=-22. Colour gradients in E/S0s increase with radius (up to 10kpc) and are negatively correlated with 10sigma + Mr (velocity dispersion relative to luminosity) and with mass density. The gradients also tend to decrease with increasing stellar age. These trends are weak or not seen in BCGs, in which the mean colour gradient is low whatever the other properties. We discuss possible explanations, which involve a greater amount of dry merging in the formation history of the BCGs.Comment: 16 pages, 24 figures, revised, accepted for publication in MNRAS
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