796 research outputs found

    The Central Correlations of Hypercharge, Isospin, Colour and Chirality in the Standard Model

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    The correlation of the fractionally represented hypercharge group with the isospin and colour group in the standard model determines as faithfully represented internal group the quotient group {\U(1)\x\SU(2)\x\SU(3)\over\Z_2\x\Z_3}. The discrete cyclic central abelian-nonabelian internal correlation involved is considered with respect to its consequences for the representations by the standard model fields, the electroweak mixing angle and the symmetry breakdown. There exists a further discrete Z2\Z_2-correlation between chirality and Lorentz properties and also a continuous \U(1)-external-internal one between hyperisospin and chirality.Comment: 18 pages, latex, macros include

    Can Digital Tools Be Used for Improving Immunization Programs?

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    In order to successfully control and eliminate vaccine-preventable infectious diseases, an appropriate vaccine coverage has to be achieved and maintained. This task requires a high level of effort as it may be compromised by a number of barriers. Public health agencies have issued specific recommendations to address these barriers and therefore improve immunization programs. In the present review, we characterize issues and challenges of immunization programs for which digital tools are a potential solution. In particular, we explore previously published research on the use of digital tools in the following vaccine-related areas: immunization registries, dose tracking, and decision support systems; vaccine-preventable diseases surveillance; surveillance of adverse events following immunizations; vaccine confidence monitoring; and delivery of information on vaccines to the public. Subsequently, we analyze the limits of the use of digital tools in such contexts and envision future possibilities and challenges

    Composition algebras and the two faces of G2G_{2}

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    We consider composition and division algebras over the real numbers: We note two r\^oles for the group G2G_{2}: as automorphism group of the octonions and as the isotropy group of a generic 3-form in 7 dimensions. We show why they are equivalent, by means of a regular metric. We express in some diagrams the relation between some pertinent groups, most of them related to the octonions. Some applications to physics are also discussed.Comment: 11 pages, 3 figure

    The Dutch language short Anterior Cruciate Ligament—Return to Sport after Injury scale has good to excellent construct validity, internal consistency, and test-retest reliability when assessing athletes undergoing rehabilitation after ACL injury or ACL reconstruction

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    Objectives: To examine the validity and reliability of the Dutch language short Anterior Cruciate Ligament—Return to Sport after Injury scale (short ACL-RSI-NL) in recreational athletes undergoing rehabilitation after ACL injury or ACL reconstruction (ACLR). Methods: The original 12-item version of the ACL-RSI had been translated into Dutch. Short ACL-RSI-NL items were derived from this 12-item Dutch version. Content validity was evaluated by a team consisting of eight ACL experts and eight athletes. A cohort of 115 athletes with ACL injury or after ACLR completed the short ACL-RSI-NL and related questionnaires at various time points during their rehabilitation. Construct validity (hypothesis testing using Spearman correlations), internal consistency (Cronbach's alpha), floor and ceiling effects (percentage of athletes having the lowest or highest score possible), and structural validity (exploratory factor analysis) were evaluated in the entire ACL athlete group. Test-retest reliability (using intra-class correlation, ICC; standard error of measurement, SEM; smallest detectable change, SDC, at both group and individual levels) was investigated in a subgroup of athletes with a stable outcome on psychological readiness within a two-week interval (n ​= ​27). Results: The short ACL-RSI-NL demonstrated good construct validity (83% of hypotheses confirmed). Internal consistency was excellent (Cronbach's alpha 0.84), and there were no floor and ceiling effects (≤13.9% lowest or highest score). Test-retest reliability was good (ICC 0.89 with 95% CI 0.77–0.95, SEM 6.93, SDC individual level 19.2, SDC group level 3.7). Exploratory factor analysis confirmed the presence of a single underlying factor (accounting for 56.4% of the total variance of the score). Conclusion: The short ACL-RSI-NL exhibited good to excellent construct validity, internal consistency, and test-retest reliability. An averaged score ranging from 0 to 100 can be used to measure psychological readiness to return to sport. The short ACL-RSI-NL has potential for use in day-to-day practice to assess the psychological readiness of recreational athletes to return to sport after ACL injury or ACLR during their rehabilitation process. Level of evidence: Level II.</p

    The G_2 sphere over a 4-manifold

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    We present a construction of a canonical G_2 structure on the unit sphere tangent bundle S_M of any given orientable Riemannian 4-manifold M. Such structure is never geometric or 1-flat, but seems full of other possibilities. We start by the study of the most basic properties of our construction. The structure is co-calibrated if, and only if, M is an Einstein manifold. The fibres are always associative. In fact, the associated 3-form results from a linear combination of three other volume 3-forms, one of which is the volume of the fibres. We also give new examples of co-calibrated structures on well known spaces. We hope this contributes both to the knowledge of special geometries and to the study of 4-manifolds.Comment: 13 page

    Attitude of Italian physicians toward pertussis diagnosis.

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    Resurgence of pertussis has been observed in several countries whereas Italy continues to be a low incidence country. We hypothesize that the low reported incidence of pertussis in Italy could be biased by the attitude of physicians to suspect and diagnose pertussis in different age groups. We investigated the attitude of Italian physicians toward pertussis diagnosis through clinical scenarios. A cross-sectional study was conducted in June 2012 sending online questionnaires to pediatricians and general practitioners (GPs) involved in ambulatory primary care. The questionnaire included five clinical scenarios of patients of different ages (45 d, 5 y, 11 y, 24 y, 58 y) with prolonged cough of at least 2 weeks. Respondents were asked to choose a diagnosis among a list of 14. We observed a decreasing trend of suspected pertussis diagnosis with increasing age of the patient (from 46% at 45 d to 0 at 58 y). In Italy pertussis is seldom suspected in the differential diagnosis of cough particularly in adults. This may cause a significant under-notification of pertussis, with a higher impact in older age groups. Educational programs should be reinforced to consider the differential diagnosis of pertussis in individuals with atypical presentation and in older age groups

    DXA-derived hip shape is related to osteoarthritis:findings from in the MrOS cohort

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    BF conducted this research whilst on a clinical research primer fellowship awarded by the Elizabeth Blackwell Institute, University of Bristol, UK. This study was funded by Arthritis Research UK project grant ref 20244. CG is funded by Arthritis Research UK grant ref 20000. The Osteoporotic Fractures in Men (MrOS) Study is supported by National Institutes of Health funding. The following institutes provide support: the National Institute on Aging (NIA), the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Center for Advancing Translational Sciences (NCATS), and NIH Roadmap for Medical Research under the following grant numbers: R01 AR052000, K24 AR048841, U01 AG027810, U01 AG042124, U01 AG042139, U01 AG042140, U01 AG042143, U01 AG042145, U01 AG042168, U01 AR066160, and UL1 TR000128.Peer reviewedPostprin

    Impact groei melkveehouderij op weidegang en landschap

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    De melkveehouderij in Nederland ontwikkelt zich door verdere schaalvergroting en langzaam de melkveestapel te vergroten. De verwachting is dat dit in Nederland leidt tot circa 10-20% hogere melkproductie, tot grotere en intensievere bedrijven, hogere melkproductie per koe en minder weidegang. Met minder koeien in de wei en meer grote stallen staat de kwaliteit van het Nederlandse cultuurlandschap onder druk. In deze studie worden de ontwikkelingen met betrekking tot de schaalvergroting in de melkveehouderij geschetst en geprognotiseerd voor 2020. Ook worden de effecten op landschap en weidegang in beeld gebracht
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