199 research outputs found

    Quantifying the uncertainties of transpiration calculations with the Penman-Monteith equation under different climate and optimum water supply conditions

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    The uncertainties of transpiration calculations with the Penman-Monteith equation were quantified under different climate conditions of Brazil, Germany and Israel using maize as a common crop type. All experiments were carried out under non-limiting growing conditions. Canopy resistance was determined by scaling to canopy level specific relations between in situ measurements of incident radiation and stomatal conductance using a light penetration model. The model was tested against heat-pulse measured sap flow in plant stems. The root mean square error (RMSE) of daily calculated transpiration minus measured sap flow was 0.4 mm/day. It was dominated by its variance component (variance = 0.2 {min/day}(2); bias = 0.0 mm/day). Calculated transpiration closely matched the measured trends at the three locations. No significant differences were found between seasons and locations. Uncertainties of canopy conductance parameterizations led to errors of up to 2.1 mm/day. The model responded most sensitively to a 30% change of net radiation (absolute bias error = 1.6 mm/day), followed by corresponding alterations of canopy resistances (0.8 mm/day), vapour pressure deficits (0.5 mm/clay) and aerodynamic resistances (0.34 mm/day). Measured and calculated 30-min or hourly averaged transpiration rates are highly correlated (r(2) = 0.95; n = 10634), and the slope of the regression line is close to unity. The overall RMSE of calculated transpiration minus measured sap flow was 0.08 mm/h and was dominated by its variance component (0.005 {mm/h}(2)). Measured sap flow consistently lagged behind calculated transpiration, because plant hydraulic capacitance delays the change of leaf water potential that drives water uptake. Calculated transpiration significantly overestimated sap flow during morning hours (mean = 0.068 mm/h, n = 321) and underestimated it during afternoon hours (mean = -0.065 mm/h; n = 316). The Penman-Monteith approach as implemented in the present study is sufficiently sensitive to detect small differences between transpiration and water uptake and provides a robust tool to manage plant water supply under unstressed conditions. (C) 2009 Elsevier B.V. All rights reserved

    NINTH ANNUAL REPORT OF THE FACULTY OF THE FREE ACADEMY, TO THE BOARD OF EDUCATION. [1860]

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    Report one from the eighth bound volume of ten which documents in part the first nineteen years of The Free Academy, the predecessor of the educational institution, City College of New York. PRESIDENT\u27S OFFICE. THE COLLEGE OF THE CITY OF NEW YORK. [FREE ACADEMY OF NEW YORK. ANNUAL REPORT OF THE FACULTY. 1860-1864.] includes 10 individual reports. At a time when municipal education constituted primary schooling, citizens united in response to arguments presented by a merchant and Board of Education President, Townsend Harris, for the necessity of an institution that would provide advanced training for future generations of citizens to fully engage in the professions advantageous to an expanding urban center. Includes preliminary reports that commented on the application of resources for the creation of the institution and the annual reports of the faculty, demonstrating accountability to the Board of Education with regard to the operation of the facility., NINTH ANNUAL REPORT OF THE FACULTY OF THE FREE ACADEMY, TO THE BOARD OF EDUCATION. [Title pages, pages 4-26. 1860], RG

    Strange particle production in proton-proton collisions at s=0.9\sqrt{s}=0.9 TeV with ALICE at the LHC

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    The production of mesons containing strange quarks (Ks0^0_s, ϕ\phi) and both singly and doubly strange baryons (Λ\Lambda, Anti-Λ\Lambda, and Ξ\Xi+Anti-Ξ\Xi) are measured at central rapidity in pp collisions at s\sqrt{s} = 0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at central rapidities for inelastic pp collisions are presented. For mesons, we report yields () of 0.184 ±\pm 0.002 stat. ±\pm 0.006 syst. for Ks0^0_s and 0.021 ±\pm 0.004 stat. ±\pm 0.003 syst. for ϕ\phi. For baryons, we find = 0.048 ±\pm 0.001 stat. ±\pm 0.004 syst. for Λ\Lambda, 0.047 ±\pm 0.002 stat. ±\pm 0.005 syst. for Anti-Λ\Lambda and 0.0101 ±\pm 0.0020 stat. ±\pm 0.0009 syst. for Ξ\Xi+Anti-Ξ\Xi. The results are also compared with predictions for identified particle spectra from QCD-inspired models and provide a baseline for comparisons with both future pp measurements at higher energies and heavy-ion collisions.Comment: 33 pages, 21 captioned figures, 10 tables, authors from page 28, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/387

    Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV

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    We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|η\eta|<0.8) and transverse momentum range 0.2< pTp_{\rm T}< 5.0 GeV/cc. The elliptic flow signal v2_2, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 ±\pm 0.002 (stat) ±\pm 0.004 (syst) in the 40-50% centrality class. The differential elliptic flow v2(pT)_2(p_{\rm T}) reaches a maximum of 0.2 near pTp_{\rm T} = 3 GeV/cc. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.Comment: 10 pages, 4 captioned figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/389

    Beyond Legalism in Turbulent Times: Re-grounding UK Social Work in a Richer International Human Rights Perspective

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    Human rights have always been intrinsically woven into social work, but in the UK, often in a way that is either vague or wholly legalistic. In this article, we make a case for embedding a broader and richer concept of human rights in UK social work practice and education. We contrast the international social work perspective on human rights with that of UK professional codes and suggest that the narrow and uninterrogated conceptualisation of human rights in the UK may be acting as a barrier to UK social workers fully understanding and engaging with broader human rights agendas of the sort found in international practice. We argue for the merits of regrounding UK social work in this broader human rights concept, in which radical and emancipatory approaches can be underpinned by a common and unifying rights-orientated perspective. We make this argument, initially, in the context of the Human Rights Act 1998 remaining in UK law, which we see as entirely necessary for the protection of human rights in social work in the country, but insufficient for a broader, richer concept. We also, however, consider a scenario in which the Act is replaced by a British Bill of Rights and argue that such a development would present a further urgent need for embedding a broader human rights concept in UK social work. We close by setting out some of what such a concept might involve

    Investigator experiences with financial conflicts of interest in clinical trials

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    <p>Abstract</p> <p>Background</p> <p>Financial conflicts of interest (fCOI) can introduce actions that bias clinical trial results and reduce their objectivity. We obtained information from investigators about adherence to practices that minimize the introduction of such bias in their clinical trials experience.</p> <p>Methods</p> <p>Email survey of clinical trial investigators from Canadian sites to learn about adherence to practices that help maintain research independence across all stages of trial preparation, conduct, and dissemination. The main outcome was the proportion of investigators that reported full adherence to preferred trial practices for all of their trials conducted from 2001-2006, stratified by funding source.</p> <p>Results</p> <p>844 investigators responded (76%) and 732 (66%) provided useful information. Full adherence to preferred clinical trial practices was highest for institutional review of signed contracts and budgets (82% and 75% of investigators respectively). Lower rates of full adherence were reported for the other two practices in the trial preparation stage (avoidance of confidentiality clauses, 12%; trial registration after 2005, 39%). Lower rates of full adherence were reported for 7 practices in the trial conduct (35% to 43%) and dissemination (53% to 64%) stages, particularly in industry funded trials. 269 investigators personally experienced (n = 85) or witnessed (n = 236) a fCOI; over 70% of these situations related to industry trials.</p> <p>Conclusion</p> <p>Full adherence to practices designed to promote the objectivity of research varied across trial stages and was low overall, particularly for industry funded trials.</p

    Exclusive photoproduction of pi degrees up to large values of Mandelstam variables s, t, and u with CLAS

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    Exclusive photoproduction cross sections have been measured for the process Îłp→pπ0(e+e−(Îł))\gamma p \rightarrow p\pi^0(e^+e^-(\gamma)) with the Dalitz decay final state using tagged photon energies in the range of EÎł=1.275−5.425E_{\gamma} = 1.275-5.425 GeV. The complete angular distribution of the final state π0\pi^0, for the entire photon energy range up to large values of tt and uu, has been measured for the first time. The data obtained show that the cross section dσ/dtd\sigma/dt, at mid to large angles, decreases with energy as s−6.89±0.26s^{-6.89\pm 0.26} . This is in agreement with the perturbative QCD quark counting rule prediction of s−7s^{-7} . Paradoxically, the size of angular distribution of measured cross sections is greatly underestimated by the QCD based Generalized Parton Distribution mechanism at highest available invariant energy s=11s=11 GeV2^2. At the same time, the Regge exchange based models for π0\pi^0 photoproduction are more consistent with experimental data.Comment: 7 pages, 6 figure

    Planck intermediate results X : Physics of the hot gas in the Coma cluster

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    Planck Intermediate Results II: Comparison of Sunyaev–Zeldovich measurements from Planck and from the Arcminute Microkelvin Imager for 11 galaxy clusters

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    A comparison is presented of Sunyaev–Zeldovich measurements for 11 galaxy clusters as obtained by Planck and by the ground-based interferom- eter, the Arcminute Microkelvin Imager. Assuming a universal spherically-symmetric Generalised Navarro, Frenk & White (GNFW) model for the cluster gas pressure profile, we jointly constrain the integrated Compton-Y parameter (Y500) and the scale radius (ξ500) of each cluster. Our resulting constraints in the Y500 − ξ500 2D parameter space derived from the two instruments overlap significantly for eight of the clusters, although, overall, there is a tendency for AMI to find the Sunyaev–Zeldovich signal to be smaller in angular size and fainter than Planck. Significant discrepancies exist for the three remaining clusters in the sample, namely A1413, A1914, and the newly-discovered Planck cluster PLCKESZ G139.59+24.18. The robustness of the analysis of both the Planck and AMI data is demonstrated through the use of detailed simulations, which also discount confusion from residual point (radio) sources and from diffuse astrophysical foregrounds as possible explanations for the discrepancies found. For a subset of our cluster sample, we have investigated the dependence of our results on the assumed pressure profile by repeating the analysis adopting the best-fitting GNFW profile shape which best matches X-ray observations. Adopting the best-fitting profile shape from the X-ray data does not, in general, resolve the discrepancies found in this subset of five clusters. Though based on a small sample, our results suggest that the adopted GNFW model may not be sufficiently flexible to describe clusters universally

    Parafoveal preview effects from word N+1 and word N+2 during reading: A critical review and Bayesian meta-analysis

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    The use of gaze-contingent display techniques to study reading has shown that readers attend not only to the currently fixated word, but also to the word to the right of the current fixation. However, a critical look at the literature shows that there are a number of questions that cannot be readily answered from the available literature reviews on the topic. First, there is no consensus on whether readers also attend to the second word to the right of fixation. Second, it is not clear whether parafoveal processing is more efficient in languages such as Chinese. Third, it is not well understood whether the measured effects are confounded by the properties of the parafoveal mask. The present study addressed these issues by performing a Bayesian meta-analysis of 93 experiments that used the boundary paradigm (Rayner, 1975). There were three main findings: 1) the advantage of previewing the second word to the right is modest in size and likely not centred on zero; 2) Chinese readers seem to make a more efficient use of parafoveal processing, but this is mostly evident in gaze duration; 3) there are interference effects associated with using different parafoveal masks that roughly increase when the mask is less word-like
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