526 research outputs found

    Composite Weak Bosons: a Lattice Analysis

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    We present a lattice analysis of a confining Yang-Mills theory without Goldstone boson. We have analytically investigated the model by a strong coupling expansion and by an intensive lattice Monte Carlo simulation using standard lattice QCD methods. We show that this theory is an interesting candidate for describing weak bosons as composite particles.Comment: Late

    Vacuum energy in a spherically symmetric background field

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    The vacuum energy of a scalar field in a spherically symmetric background field is considered. It is expressed through the Jost function of the corresponding scattering problem. The renormalization is discussed in detail and performed using the uniform asymptotic expansion of the Jost function. The method is demonstrated in a simple explicit example.Comment: 14 pages, 1 Postscript figur

    Collision-Induced Decay of Metastable Baby Skyrmions

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    Many extensions of the standard model predict heavy metastable particles which may be modeled as solitons (skyrmions of the Higgs field), relating their particle number to a winding number. Previous work has shown that the electroweak interactions admit processes in which these solitons decay, violating standard model baryon number. We motivate the hypothesis that baryon-number-violating decay is a generic outcome of collisions between these heavy particles. We do so by exploring a 2+1 dimensional theory which also possesses metastable skyrmions. We use relaxation techniques to determine the size, shape and energy of static solitons in their ground state. These solitons could decay by quantum mechanical tunneling. Classically, they are metastable: only a finite excitation energy is required to induce their decay. We attempt to induce soliton decay in a classical simulation by colliding pairs of solitons. We analyze the collision of solitons with varying inherent stabilities and varying incident velocities and orientations. Our results suggest that winding-number violating decay is a generic outcome of collisions. All that is required is sufficient (not necessarily very large) incident velocity; no fine-tuning of initial conditions is required.Comment: 24 pages, 7 figures, latex. Very small changes onl

    Composite Weak Bosons: a Lattice Monte Carlo Analysis

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    We present a lattice Monte Carlo simulation for the evaluation of the spectrum of a confining Yang-Mills theory without Goldstone boson. We show that this theory is a very good candidate for describing composite weak bosons. In order to perform the spectrum analysis we have used standard lattice QCD Monte Carlo methods. We have also developed an efficient method to evaluate the mass of the pseudoscalar isosinglet which is present in our theory.Comment: Late

    The Stability of the Weak Skyrmions

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    We consider a set of gauge invariant terms in higher order effective Lagrangians of the strongly interacting scalar of the electroweak theory. The terms are introduced in the framework of the hidden gauge symmetry formalism. The usual gauge term is known to stabilize the skyrmion but only in the large vector mass limit. We find that adding higher-order gauge terms is insufficient to insure stability. We then proceed to analyze other gauge invariant interaction terms. Some of the conclusions also apply to QCD skyrmions.Comment: 3 pages, revtex v3, (optional), LAVAL-PHY-11-9

    CP Violation from Surface Terms in the Electroweak Theory without Fermions

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    We consider the effect of adding a CP-odd, theta FFdual-term to the electroweak Lagrangian without fermions. This term affects neither the classical nor perturbatively quantum physics, but can be observed through non-perturbative quantum processes. We give an example of such a process by modifying the theory so that it supports Higgs-winding solitons and showing that the rates of decay of these solitons to specific final states are CP violating. We also discuss how the CP symmetry is restored when fermions are included.Comment: 11 pages, REVTEX, final version to be published in Phys. Rev.

    Urinary Epidermal Growth Factor as a Marker of Disease Progression in Children With Nephrotic Syndrome

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    © 2019 International Society of Nephrology Introduction: Childhood-onset nephrotic syndrome has a variable clinical course. Improved predictive markers of long-term outcomes in children with nephrotic syndrome are needed. This study tests the association between baseline urinary epidermal growth factor (uEGF) excretion and longitudinal kidney function in children with nephrotic syndrome. Methods: The study evaluated 191 participants younger than 18 years enrolled in the Nephrotic Syndrome Study Network, including 118 with their first clinically indicated kidney biopsy (68 minimal change disease; 50 focal seNorthwell Healthntal glomerulosclerosis) and 73 with incident nephrotic syndrome without a biopsy. uEGF was measured at baseline for all participants and normalized by the urine creatinine (Cr) concentration. Renal epidermal growth factor (EGF) mRNA was measured in the tubular compartment microdissected from kidney biopsy cores from a subset of patients. Linear mixed models were used to test if baseline uEGF/Cr and EGF mRNA expression were associated with change in estimated glomerular filtration rate (eGFR) over time. Results: Higher uEGF/Cr at baseline was associated with slower eGFR decline during follow-up (median follow-up = 30 months). Halving of uEGF/Cr was associated with a decrease in eGFR slope of 2.0 ml/min per 1.73 m2 per year (P \u3c 0.001) adjusted for age, race, diagnosis, baseline eGFR and proteinuria, and APOL1 genotype. In the biopsied subgroup, uEGF/Cr was correlated with EGF mRNA expression (r = 0.74; P \u3c 0.001), but uEGF/Cr was retained over mRNA expression as the stronger predictor of eGFR slope after multivariable adjustment (decrease in eGFR slope of 1.7 ml/min per 1.73 m2 per year per log2 decrease in uEGF/Cr; P \u3c 0.001). Conclusion: uEGF/Cr may be a useful noninvasive biomarker that can assist in predicting the long-term course of kidney function in children with incident nephrotic syndrome

    Text Messaging for Disease Monitoring in Childhood Nephrotic Syndrome

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    © 2019 International Society of Nephrology Introduction: There is limited information on effective disease monitoring for prompt interventions in childhood nephrotic syndrome. We examined the feasibility and effectiveness of a novel text messaging system (SMS) for disease monitoring in a multicenter, prospective study. Methods: A total of 127 patients results, symptoms, and medication adherence were sent to a designated caregiver (n = 116) or adolescent patient (n = 3). Participants responded by texting. Feasibility of SMS was assessed by SMS adoption, retention, and engagement, and concordance between participant-reported results and laboratory/clinician assessments. The number of disease relapses and time-to-remission data captured by SMS were compared with data collected by conventional visits. Results: A total of 119 of 127 (94%) patients agreed to SMS monitoring. Retention rate was 94%, with a median follow-up of 360 days (interquartile range [IQR] 353–362). Overall engagement was high, with a median response rate of 87% (IQR, 68–97). Concordance between SMS-captured home urine protein results and edema status with same-day in-person study visit was excellent (kappa values 0.88 and 0.92, respectively). SMS detected a total of 108 relapse events compared with 41 events captured by scheduled visits. Median time to remission after enrollment was 22 days as captured by SMS versus 50 days as captured by scheduled visits. Conclusion: SMS was well accepted by caregivers and adolescent patients and reliably captured nephrotic syndrome disease activity between clinic visits. Additional studies are needed to explore the impact of SMS on disease outcomes

    A mediation approach to understanding socio-economic inequalities in maternal health-seeking behaviours in Egypt.

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    BACKGROUND: The levels and origins of socio-economic inequalities in health-seeking behaviours in Egypt are poorly understood. This paper assesses the levels of health-seeking behaviours related to maternal care (antenatal care [ANC] and facility delivery) and their accumulation during pregnancy and childbirth. Secondly, it explores the mechanisms underlying the association between socio-economic position (SEP) and maternal health-seeking behaviours. Thirdly, it examines the effectiveness of targeting of free public ANC and delivery care. METHODS: Data from the 2008 Demographic and Health Survey were used to capture two latent constructs of SEP: individual socio-cultural capital and household-level economic capital. These variables were entered into an adjusted mediation model, predicting twelve dimensions of maternal health-seeking; including any ANC, private ANC, first ANC visit in first trimester, regular ANC (four or more visits during pregnancy), facility delivery, and private delivery. ANC and delivery care costs were examined separately by provider type (public or private). RESULTS: While 74.2% of women with a birth in the 5-year recall period obtained any ANC and 72.4% delivered in a facility, only 48.8% obtained the complete maternal care package (timely and regular facility-based ANC as well as facility delivery) for their most recent live birth. Both socio-cultural capital and economic capital were independently positively associated with receiving any ANC and delivering in a facility. The strongest direct effect of socio-cultural capital was seen in models predicting private provider use of both ANC and delivery. Despite substantial proportions of women using public providers reporting receipt of free care (ANC: 38%, delivery: 24%), this free-of-charge public care was not effectively targeted to women with lowest economic resources. CONCLUSIONS: Socio-cultural capital is the primary mechanism leading to inequalities in maternal health-seeking in Egypt. Future studies should therefore examine the objective and perceived quality of care from different types of providers. Improvements in the targeting of free public care could help reduce the existing SEP-based inequalities in maternal care coverage in the short term

    Patient and caregiver perspectives on blood pressure in children with chronic kidney disease

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    Background: More than 50% of children with chronic kidney disease (CKD) have uncontrolled hypertension, increasing their long-term risk of cardiovascular disease and progression to kidney failure. Children receiving medications or dialysis may also experience acute blood pressure fluctuations accompanied by debilitating symptoms. We aimed to describe the perspectives of children with CKD and their parental caregivers on blood pressure to inform patient-centered care. / Methods: Secondary thematic analysis was conducted on qualitative data from the Standardized Outcomes in Nephrology—Children and Adolescents initiative, encompassing 16 focus groups, an international Delphi survey and two consensus workshops. We analyzed responses from children with CKD (ages 8–21 years) and caregivers (of children ages 0–21 years) pertaining to blood pressure. / Results: Overall, 120 patients and 250 caregivers from 22 countries participated. We identified five themes: invisibility and normalization (reassured by apparent normotension, absence of symptoms and expected links with CKD), confused by ambiguity (hypertension indistinguishable from cardiovascular disease, questioning the need for prophylactic intervention, frustrated by inconsistent messages and struggling with technical skills in measurement), enabling monitoring and maintaining health (gaging well-being and preventing vascular complications), debilitating and constraining daily living (provoking anxiety and agitation, helpless and powerless and limiting life activities) and burden of medications (overwhelmed by the quantity of tablets and distress from unexpected side effects). / Conclusions: For children with CKD and their caregivers, blood pressure was an important heath indicator, but uncertainty around its implications and treatment hampered management. Providing educational resources to track blood pressure and minimizing symptoms and treatment burden may improve outcomes in children with CKD
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