41 research outputs found
The PDF4LHC21 combination of global PDF fits for the LHC Run III
A precise knowledge of the quark and gluon structure of the proton, encoded
by the parton distribution functions (PDFs), is of paramount importance for the
interpretation of high-energy processes at present and future lepton-hadron and
hadron-hadron colliders. Motivated by recent progress in the PDF determinations
carried out by the CT, MSHT, and NNPDF groups, we present an updated
combination of global PDF fits: PDF4LHC21. It is based on the Monte Carlo
combination of the CT18, MSHT20, and NNPDF3.1 sets followed by either its
Hessian reduction or its replica compression. Extensive benchmark studies are
carried out in order to disentangle the origin of the differences between the
three global PDF sets. In particular, dedicated fits based on almost identical
theory settings and input datasets are performed by the three groups,
highlighting the role played by the respective fitting methodologies. We
compare the new PDF4LHC21 combination with its predecessor, PDF4LHC15,
demonstrating their good overall consistency and a modest reduction of PDF
uncertainties for key LHC processes such as electroweak gauge boson production
and Higgs boson production in gluon fusion. We study the phenomenological
implications of PDF4LHC21 for a representative selection of inclusive,
fiducial, and differential cross sections at the LHC. The PDF4LHC21 combination
is made available via the LHAPDF library and provides a robust, user-friendly,
and efficient method to estimate the PDF uncertainties associated to
theoretical calculations for the upcoming Run III of the LHC and beyond.Comment: 87 pages, 44 figures, 11 table
Post-LS3 Experimental Options in ECN3
The Experimental Cavern North 3 (ECN3) is an underground experimental cavern
on the CERN Pr\'evessin site. ECN3 currently hosts the NA62 experiment, with a
physics programme devoted to rare kaon decays and searches of hidden particles
approved until Long Shutdown 3 (LS3). Several options are proposed on the
longer term in order to make best use of the worldwide unique potential of the
high-intensity/high-energy proton beam extracted from the Super Proton
Synchrotron (SPS) in ECN3. The current status of their study by the CERN
Physics Beyond Colliders (PBC) Study Group is presented, including
considerations on beam requirements and upgrades, detector R&D and
construction, schedules and cost, as well as physics potential within the CERN
and worldwide landscape.Comment: 113 pages, 39 figure
Feel4Diabetes healthy diet score: Development and evaluation of clinical validity
Background: The aim of this paper is to present the development of the Feel4Diabetes Healthy Diet Score and to evaluate its clinical validity. Methods: Study population consisted of 3268 adults (63% women) from high diabetes risk families living in 6 European countries. Participants filled in questionnaires at baseline and after 1 year, reflecting the dietary goals of the Feel4Diabetes intervention. Based on these questions the Healthy Diet Score was constructed, consisting of the following components: breakfast, vegetables, fruit and berries, sugary drinks, whole-grain cereals, nuts and seeds, low-fat dairy products, oils and fats, red meat, sweet snacks, salty snacks, and family meals. Maximum score for each component was set based on its estimated relative importance regarding T2DM risk, higher score indicating better quality of diet. Clinical measurements included height, weight, waist circumference, heart rate, blood pressure, and fasting blood sampling, with analyses of glucose, total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglycerides. Analysis of (co) variance was used to compare the Healthy Diet Score and its components between countries and sexes using baseline data, and to test differences in clinical characteristics between score categories, adjusted for age, sex and country. Pearson''s correlations were used to study the association between changes from baseline to year 1 in the Healthy Diet Score and clinical markers. To estimate reproducibility, Pearson''s correlations were studied between baseline and 1 year score, within the control group only. Results: The mean total score was 52.8 ± 12.8 among women and 46.6 ± 12.8 among men (p < 0.001). The total score and its components differed between countries. The change in the Healthy Diet Score was significantly correlated with changes in BMI, waist circumference, and total and LDL cholesterol. The Healthy Diet Score as well as its components at baseline were significantly correlated with the values at year 1, in the control group participants. Conclusion: The Feel4Diabetes Healthy Diet Score is a reproducible method to capture the dietary information collected with the Feel4Diabetes questionnaire and measure the level of and changes in the adherence to the dietary goals of the intervention. It gives a simple parameter that associates with clinical risk factors in a meaningful manner
Factors associated with risk of developmental delay in preschool children in a setting with high rates of malnutrition : a cross-sectional analysis of data from the IHOPE study, Madagascar
Background 50% of Malagasy children have moderate to severe stunting. In 2016, a new 10 year National Nutrition Action Plan (PNAN III) was initiated to help address stunting and developmental delay. We report factors associated with risk of developmental delay in 3 and 4 year olds in the rural district of Ifanadiana in southeastern Madagascar in 2016. Methods The data are from a cross-sectional analysis of the 2016 wave of IHOPE panel data (a population-representative cohort study begun in 2014). We interviewed women ages 15-49 using the MICS Early Child Development Indicator (ECDI) module, which includes questions for physical, socio-emotional, learning and literacy/numeracy domains. We analyzed ECDI data using standardized z scores for relative relationships for 2 outcomes: at-risk-for-delay vs. an international standard, and lower-development-than-peers if ECDI z scores were > 1 standard deviation below study mean. Covariates included demographics, adult involvement, household environment, and selected child health factors. Variables significant at alpha of 0.1 were included a multivariable model; final models used backward stepwise regression, clustered at the sampling level. Results Of 432 children ages 3 and 4 years, 173 (40%) were at risk for delay compared to international norms and 68 children (16.0%) had lower-development than peers. This was driven mostly by the literacy/numeracy domain, with only 7% of children considered developmentally on track in that domain. 50.5% of children had moderate to severe stunting. 76 (17.6%) had > = 4 stimulation activities in past 3 days. Greater paternal engagement (OR 1.5 (1.09, 2.07)) was associated with increased delay vs. international norms. Adolescent motherhood (OR. 4.09 (1.40, 11.87)) decreased children's development vs. peers. Engagement from a non-parental adult reduced odds of delay for both outcomes (OR (95%CI = 0.76 (0.63, 0.91) & 0.27 (0.15, 0 48) respectively). Stunting was not associated with delay risk (1.36 (0.85, 2.15) or low development (0.92 (0.48, 1.78)) when controlling for other factors. Conclusions In this setting of high child malnutrition, stunting is not independently associated with developmental risk. A low proportion of children receive developmentally supportive stimulation from adults, but non-parent adults provide more stimulation in general than either mother or father. Stimulation from non-parent adults is associated with lower odds of delay
The PDF4LHC21 combination of global PDF fits for the LHC Run III
A precise knowledge of the quark and gluon structure of the proton, encoded by the parton distribution functions (PDFs), is of paramount importance for the interpretation of high-energy processes at present and future lepton–hadron and hadron–hadron colliders. Motivated by recent progress in the PDF determinations carried out by the CT, MSHT, and NNPDF groups, we present an updated combination of global PDF fits: PDF4LHC21. It is based on the Monte Carlo combination of the CT18, MSHT20, and NNPDF3.1 sets followed by either its Hessian reduction or its replica compression. Extensive benchmark studies are carried out in order to disentangle the origin of the differences between the three global PDF sets. In particular, dedicated fits based on almost identical theory settings and input datasets are performed by the three groups, highlighting the role played by the respective fitting methodologies. We compare the new PDF4LHC21 combination with its predecessor, PDF4LHC15, demonstrating their good overall consistency and a modest reduction of PDF uncertainties for key LHC processes such as electroweak gauge boson production and Higgs boson production in gluon fusion. We study the phenomenological implications of PDF4LHC21 for a representative selection of inclusive, fiducial, and differential cross sections at the LHC. The PDF4LHC21 combination is made available via the LHAPDF library and provides a robust, user-friendly, and efficient method to estimate the PDF uncertainties associated to theoretical calculations for the upcoming Run III of the LHC and beyond