269 research outputs found

    Phenotypic and genetic influences on test-day measures of acetone concentration in milk.

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    The objectives of this study were to estimate heritability of acetone concentration in milk, based on monthly samples of milk obtained as part of a routine milk testing program, and to evaluate the feasibility of using such data in a genetic evaluation program for selection against ketosis incidence. Milk samples were collected from January to December of 1999 in herds enrolled in the Ontario Dairy Herd Improvement Association, and acetone concentration was measured using an inline chemical procedure. The original data included more than 50,000 records. Because ketosis is generally a problem during early lactation, only the single test with the fewest days in milk was retained. In addition, data were retained only for cows with pedigree information. The final data set included 10,375 records. Among these data, only 6.56% had detectable levels of acetone. Acetone data were log-transformed prior to statistical analysis. Simple ANOVA indicated that herd, parity number, days in milk, and month of test had significant effects on acetone concentration. Acetone levels increased with lactation number and were higher in early lactation. Three approaches were applied for genetic analysis. First, REML was used with a simple linear animal model. Then, a separate procedure used data augmentation and Gibbs Sampling to obtain continuously distributed underlying values for records with zero acetone concentration, and these data were analyzed with both an animal and sire model. Heritability of acetone concentration was less than 1% for all 3 analyses. Herd effects accounted for about 5% of the phenotypic variance. Low estimates of heritability were due either to low actual levels of genetic variance or inability to detect all of the genetic variance present, due to infrequent recording during the early part of the lactation. Genetic evaluation based on recording of acetone concentration on a monthly basis seems of little use as a selection tool to decrease incidence of ketosis

    Towards an Asymptotic-Safety Scenario for Chiral Yukawa Systems

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    We search for asymptotic safety in a Yukawa system with a chiral U(NL)L⊗U(1)RU(N_L)_L\otimes U(1)_R symmetry, serving as a toy model for the standard-model Higgs sector. Using the functional RG as a nonperturbative tool, the leading-order derivative expansion exhibits admissible non-Ga\ssian fixed-points for 1≀NL≀571 \leq N_L \leq 57 which arise from a conformal threshold behavior induced by self-balanced boson-fermion fluctuations. If present in the full theory, the fixed-point would solve the triviality problem. Moreover, as one fixed point has only one relevant direction even with a reduced hierarchy problem, the Higgs mass as well as the top mass are a prediction of the theory in terms of the Higgs vacuum expectation value. In our toy model, the fixed point is destabilized at higher order due to massless Goldstone and fermion fluctuations, which are particular to our model and have no analogue in the standard model.Comment: 16 pages, 8 figure

    Africa's digital future

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    The main thrust of this book is to examine whether Africa is in a position to benefit from the digital age, given the continent’s many development challenges and slow adoption of digital technologies. While there is substantial literature on the digital economy and the quickening pace of the Fourth Industrial Revolution (4IR), comparatively little research has been conducted on what the digital age means for Africa. This book aims to close this research gap by using various qualitative and quantitative research methodologies to arrive at a cross-section of original findings and perspectives on how Africa can capitalise on the benefits of digital developments, including their potential to create jobs and bring about more inclusive growth. The book’s main contribution is its coverage of a range of topics that will affect Africa’s digital future, including industrialisation, global value chains, transport and logistics, trade facilitation, labour-market dynamics, employment and education. The theme of digital trade forms a backdrop to many of the chapters, along with references to the COVID-19 pandemic. The book acknowledges that although African countries should learn from international best practices, they need to chart their own course according to their own particular circumstances. By adopting a digital mindset, countries should be able to diversify economically and extend their market reach across the continent. Furthermore, while Africa should be looking to the future and determining how digital technologies can become effective tools of sustainable development, the continent has much catching up to do

    Africa's digital future

    Get PDF
    The main thrust of this book is to examine whether Africa is in a position to benefit from the digital age, given the continent’s many development challenges and slow adoption of digital technologies. While there is substantial literature on the digital economy and the quickening pace of the Fourth Industrial Revolution (4IR), comparatively little research has been conducted on what the digital age means for Africa. This book aims to close this research gap by using various qualitative and quantitative research methodologies to arrive at a cross-section of original findings and perspectives on how Africa can capitalise on the benefits of digital developments, including their potential to create jobs and bring about more inclusive growth. The book’s main contribution is its coverage of a range of topics that will affect Africa’s digital future, including industrialisation, global value chains, transport and logistics, trade facilitation, labour-market dynamics, employment and education. The theme of digital trade forms a backdrop to many of the chapters, along with references to the COVID-19 pandemic. The book acknowledges that although African countries should learn from international best practices, they need to chart their own course according to their own particular circumstances. By adopting a digital mindset, countries should be able to diversify economically and extend their market reach across the continent. Furthermore, while Africa should be looking to the future and determining how digital technologies can become effective tools of sustainable development, the continent has much catching up to do

    Asymptotic safety of simple Yukawa systems

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    We study the triviality and hierarchy problem of a Z_2-invariant Yukawa system with massless fermions and a real scalar field, serving as a toy model for the standard-model Higgs sector. Using the functional RG, we look for UV stable fixed points which could render the system asymptotically safe. Whether a balancing of fermionic and bosonic contributions in the RG flow induces such a fixed point depends on the algebraic structure and the degrees of freedom of the system. Within the region of parameter space which can be controlled by a nonperturbative next-to-leading order derivative expansion of the effective action, we find no non-Gaussian fixed point in the case of one or more fermion flavors. The fermion-boson balancing can still be demonstrated within a model system with a small fractional flavor number in the symmetry-broken regime. The UV behavior of this small-N_f system is controlled by a conformal Higgs expectation value. The system has only two physical parameters, implying that the Higgs mass can be predicted. It also naturally explains the heavy mass of the top quark, since there are no RG trajectories connecting the UV fixed point with light top masses.Comment: 14 pages, 3 figures, v2: references added, typos corrected, minor numerical correction

    Beliefs and expectations of rural hospital practitioners towards a developing trauma system: A qualitative case study

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    Background: An understanding of stakeholders’ views is key to the successful development and operation of a rural trauma system. Scotland, which has large remote and rural areas, is currently implementing a national trauma system. The aim of this study was to identify key barriers and enablers to the development of an effective trauma system from the perspective of rural healthcare professionals. Methods: This is a qualitative study, which was conducted in rural general hospitals (RGH) in Scotland, from April to June 2017. We used an opportunistic sampling strategy to include hospital providers of rural trauma care across the region. Semi-structured interviews were conducted, recorded, and transcribed. Thematic analysis was used to identify and group participant perspectives on key barriers and enablers to the development of the new trauma system. Results: We conducted 15 interviews with 18 participants in six RGHs. Study participants described barriers and enablers across three themes: 1) quality of care, 2) interfaces within the system and 3) interfaces with the wider healthcare system. For quality of care, enablers included confidence in basic trauma management, whilst a perceived lack of change from current management was seen as a barrier. The theme of interfaces within the system identified good interaction with other services and a single point of contact for referral as enablers. Perceived barriers included challenges in referring to tertiary care. The final theme of interfaces with the wider healthcare system included an improved transport system, increased audit resource and coordinated clinical training as enablers. Perceived barriers included a rural staffing crisis and problematic patient transfer to further care. Conclusions: This study provides insight into rural professionals’ perceptions regarding the implementation of a trauma system in rural Scotland. Barriers included practical issues, such as retrieval, transfer and referral processes. Importantly, there is a degree of uncertainty, discontent and disengagement towards trauma system development, and concerns regarding staffing levels and governance. These issues are unlikely to be unique to Scotland and warrant further study to inform service planning and the effective delivery of rural trauma systems

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio
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