A Shape Theorem for Riemannian First-Passage Percolation

Riemannian first-passage percolation (FPP) is a continuum model, with a distance function arising from a random Riemannian metric in $\R^d$. Our main result is a shape theorem for this model, which says that large balls under this metric converge to a deterministic shape under rescaling. As a consequence, we show that smooth random Riemannian metrics are geodesically complete with probability one

Infant Illness Severity and Perinatal Post-traumatic Stress Disorder after Discharge from the Neonatal Intensive Care Unit

Background Risk factors for perinatal posttraumatic stress disorder (PTSD) among parents of an infant in the NICU have varied in previous literature. The relationships between perception of illness severity and objective measures of illness severity with PTSD are not well understood. Aims To determine if PTSD among parents after an infant NICU discharge can be predicted by 1) objective measures of infant illness severity or 2) perceptions of infant illness severity. Study design A prospective, observational study. Subjects Parent/infant dyads who were in the NICU for ≥14 days. Outcome measures Objective measures of illness severity were obtained from the electronic health record. Perceptions of illness were measured by the response to the question, “How sick is your child/patient?” on a 5-point Likert scale. The Perinatal Post-Traumatic Stress Disorder Questionnaire (PPQ) was completed by parents three months after discharge. Results One hundred ninety-four dyads participated in the study, 86% of parents completed follow up screening. 25% of parents screened positive for PTSD. Parents perceived infants to be sick more often than hospital caregivers. In bivariate analysis many objective measures of illness severity were associated with PTSD. Parent perceptions of illness were also associated with PTSD after adjusting for objective measures of illness (OR 3.2, 95% CI 1.1–6.1, p = 0.008). Conclusions PTSD in parents after NICU discharge is multifactorial. Objective illness risk factors can be used to screen parents at risk. Hospital caregivers should strive to understand parents\u27 perception of illness and improve communication to potentially decrease PTSD after discharge

Group Incentives and Rational Voting

Our model describes competition between groups driven by the choices of self-interested voters within groups. Within a Poisson voting environment, parties observe aggregate support from groups and can allocate prizes or punishments to them. In a tournament style analysis, the model characterizes how contingent allocation of prizes based on relative levels of support affects equilibrium voting behavior. In addition to standard notions of pivotality, voters influence the distribution of prizes across groups. Such prize pivotality supports positive voter turnout even in non-competitive electoral settings. The analysis shows that competition for a prize awarded to the most supportive group is only stable when two groups actively support a party. However, competition among groups to avoid punishment is stable in environments with any number of groups. We conclude by examining implications for endogenous group formation and how politicians structure the allocation of rewards and punishments.Comment: 34 pages, 1 figur

Utility of echocardiography in predicting mortality in infants with severe bronchopulmonary dysplasia

This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Objective: To determine the relationship between interventricular septal position (SP) and right ventricular systolic pressure (RVSP) and mortality in infants with severe BPD (sBPD). Study design: Infants with sBPD in the Children's Hospitals Neonatal Database who had echocardiograms 34-44 weeks' postmenstrual age (PMA) were included. SP and RVSP were categorized normal, abnormal (flattened/bowed SP or RVSP > 40 mmHg) or missing. Results: Of 1157 infants, 115 infants (10%) died. Abnormal SP or RVSP increased mortality (SP 19% vs. 8% normal/missing, RVSP 20% vs. 9% normal/missing, both p < 0.01) in unadjusted and multivariable models, adjusted for significant covariates (SP OR 1.9, 95% CI 1.2-3.0; RVSP OR 2.2, 95% CI 1.1-4.7). Abnormal parameters had high specificity (SP 82%; RVSP 94%), and negative predictive value (SP 94%, NPV 91%) for mortality. Conclusions: Abnormal SP or RVSP is independently associated with mortality in sBPD infants. Negative predictive values distinguish infants most likely to survive

Top Quark Physics

We review the prospects for studies of the top quark at the LHC.We review the prospects for studies of the top quark at the LHC. Members of the working group who have contributed to this document are: A.Ahmadov, G.Azuelos, U.Baur, A.Belyaev, E.L.Berger, W.Bernreuther, E.E.Boos, M.Bosman, A.Brandenburg, R.Brock, M.Buice, N.Cartiglia, F.Cerutti, A.Cheplakov, L.Chikovani, M.Cobal-Grassmann, G.Corcella, F.del Aguila, T.Djobava, J.Dodd, V.Drollinger, A.Dubak, S.Frixione, D.Froidevaux, B.Gonzalez Pineiro, Y.P.Gouz, D.Green, P.Grenier, S.Heinemeyer, W.Hollik, V.Ilyin, C.Kao, A.Kharchilava, R. Kinnunen, V.V.Kukhtin, S.Kunori, L.La Rotonda, A.Lagatta, M.Lefebvre, K.Maeshima, G.Mahlon, S.Mc Grath, G.Medin, R.Mehdiyev, B.Mele, Z.Metreveli, D.O'Neil, L.H.Orr, D.Pallin, S.Parke, J.Parsons, D.Popovic, L.Reina, E.Richter-Was, T.G.Rizzo, D.Salihagic, M.Sapinski, M.H.Seymour, V.Simak, L.Simic, G.Skoro, S.R.Slabospitsky, J.Smolik, L.Sonnenschein, T.Stelzer, N.Stepanov, Z.Sullivan, T.Tait, I.Vichou, R.Vidal, D.Wackeroth, G.Weiglein, S.Willenbrock, W.W

Top anti-top quark spin correlations and the potential of observation of CP volation in the production vertex

Heavy quarks have special properties. The decay and production mechanism is mentioned. Large statistics of t-quarks can significantly contribute to understand the mass and properties of quarks. Also a possible new interactions in the strong vertex, involving supersymetric particles, several Higgs fields, may contribute to observable quantities. Such dynamics may be detected via asymmetry, which may reflect CP-violation in the strong production vertex. Some possibilities to study of this effects at the LHC energies in ATLAS experiment is subject of this note

Predicting Death Or Tracheostomy Placement In Infants With Severe Bronchopulmonary Dysplasia

Objective:To estimate the risk of death or tracheostomy placement (D/T) in infants with severe bronchopulmonary dysplasia (sBPD) born \u3c32 weeks\u27 gestation referred to regional neonatal intensive care units.Study Design:We conducted a retrospective cohort study in infants born \u3c32 weeks\u27 gestation with sBPD in 2010-2011, using the Children\u27s Hospital Neonatal Database. sBPD was defined as the need for FiO 2 ≥0.3, nasal cannula support \u3e2 l min -1 or positive pressure at 36 weeks\u27 post menstrual age. The primary outcome was D/T before discharge. Predictors associated with D/T in bivariable analyses (P\u3c0.2) were used to develop a multivariable logistic regression equation using 80% of the cohort. This equation was validated in the remaining 20% of infants.Result:Of 793 eligible patients, the mean gestational age was 26 weeks\u27 and the median age at referral was 6.4 weeks. D/T occurred in 20% of infants. Multivariable analysis showed that later gestational age at birth, later age at referral along with pulmonary management as the primary reason for referal, mechanical ventilation at the time of referral, clinically diagnosed pulmonary hypertension, systemic corticosteroids after referral and occurrence of a bloodstream infection after referral were each associated with D/T. The model performed well with validation (area under curve 0.86, goodness-of-fit χ 2, P=0.66).Conclusion:Seven clinical variables predicted D/T in this large, contemporary cohort with sBPD. These results can be used to inform clinicians who counsel families of affected infants and to assist in the design of future prospective trials. © 2014 Nature America, Inc