260 research outputs found

    Pyeloplasty in children: is there a difference in patients with or without crossing lower pole vessel?

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    Introduction: Most of the children with hydronephrosis do not require any surgical intervention. However, in individual cases, irreversible loss of renal function can develop. Predictive criteria have been proven ineffective so far in determining in which children obstruction will lead to renal damage. The aim of our retrospective study was to determine the role of a crossing lower pole vessel (CV) in children undergoing pyeloplasty. Materials and methods: Between 1996 and 2003, 137 patients (age between 6weeks and 16years) with unilateral ureteropelvic junction obstruction and no associated urological pathologies underwent Anderson-Hynes dismembered pyeloplasty. A total of 112 patients were evaluated with complete data. One of the following criteria was considered to be indication for surgery in children with grade 4 hydronephrosis: differential renal function (DRF) 10% and washout patterns II or III b according to O'Reilly. We looked at the age during surgery and the kind of presentation. DRF was measured using diuretic renography preoperatively and 1year postoperatively. A postoperative change in DRF of group A (children without CV, n=84) was compared to that in group B (children with CV, n=28). Results: Median age at the time of surgery was 5months in group A compared to 23months in group B. Only in 21.4% of the children with CV compared to 60.7% without CV hydronephrosis was diagnosed by ultrasound examination antenatally. We found a preoperative DRF of 42.4%±11.2 SD in group A, and of 38.9%±11.7 SD in group B. The percentage of postoperative improvement was 3.3% in group A and 15.4% in group B. Conclusions: Children with ureteropelvic junction obstruction and CV received a delayed surgical treatment and showed a greater reduction in differential renal function preoperatively, in contrast to patients without CV. Our data show that CV is a risk factor for deterioration of renal function in children with hydronephrosis and we advocate for an early pyeloplasty in these children, especially if they have a high-grade dilatation and equivocal washout patterns in diuretic renographies. Further prospective studies are necessary in order to understand the natural history of CV and to reveal the importance of the crossing lower pole vessel as a structural anomaly lacking maturatio

    CP-odd observables in neutralino production with transverse e+ and e- beam polarization

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    We consider neutralino production and decay e^+e^ --> chi^0_i chi^0_j, chi^0_j --> chi^0_1 f \bar{f} at a linear collider with transverse e^+ and e^- beam polarization. We propose CP asymmetries by means of the azimuthal distribution of the produced neutralinos and of that of the final leptons, while taking also into account the subsequent decays of the neutralinos. We include the complete spin correlations between production and decay. Our framework is the Minimal Supersymmetric Standard Model with complex parameters. In a numerical study we show that there are good prospects to observe these CP asymmetries at the International Linear Collider and estimate the accuracy expected for the determination of the phases in the neutralino sector.Comment: 30 pages, minor changes in the introduction, references adde

    Hospital-based, prospective, multicentre surveillance to determine the incidence of intussusception in children aged below 15 years in Germany

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    <p>Abstract</p> <p>Background</p> <p>A new vaccine against Rotavirus (RV) gastroenteritis was introduced in Germany in 2006. In 1997 the first RV vaccine was withdrawn due to an increased incidence in intussusception (IS). Thus, an accurate estimation of the incidence of IS is important for post-licensure surveillance.</p> <p>Methods</p> <p>IS-Data were obtained from the 'Erhebungseinheit für seltene pädiatrische Erkrankungen Deutschland' (ESPED, German surveillance unit for rare pediatric diseases) collaborations' central register where all cases of intussusception in Germany for the years 2006 and 2007 are collected (n = 1200). In order to obtain an unbiased estimate of the incidence, it is necessary to determine the population under risk out of which these cases originated, and the proportion of real cases not reported to the registry (underreporting). In order to assess underreporting, a random sample of 31 hospitals was re-assessed by an outside reviewer. The estimation of incidence was done using a single Maximum-Likelihood (ML) estimator based on data from both the registry and the sample.</p> <p>Results</p> <p>The uncorrected observed incidence was calculated to be 26.6/100,000 child-years for children below 1 year old, 23.8 for those below 2 years old, and 5.2 for those below 15 years old. The review revealed a mean reporting quota of about 41% and the ML approach yielded an incidence of 51.5/100,000 child-years (95%CI [41.7;61.1]) for children below 2 years of age.</p> <p>Conclusions</p> <p>While substantial under-reporting led to very conservative estimates of the IS incidence, the approach described here allows an accurate estimation of IS incidence including corresponding confidence bands. Therefore, ML estimation is a straightforward instrument to derive stable, unbiased estimates in epidemiological studies with incomplete data.</p

    Determination of the Michel Parameters and the tau Neutrino Helicity in tau Decay

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    Using the CLEO II detector at the e+ee^+e^- storage ring CESR, we have determined the Michel parameters ρ\rho, ξ\xi, and δ\delta in τlννˉ\tau^\mp \to l^\mp\nu\bar{\nu} decay as well as the tau neutrino helicity parameter hντh_{\nu_\tau} in τππ0ν\tau^\mp \to \pi^\mp\pi^0\nu decay. From a data sample of 3.02×1063.02\times 10^6 tau pairs produced at s=10.6GeV\sqrt{s}=10.6 GeV, using events of the topology e+eτ+τ(l±ννˉ)(ππ0ν)e^+e^- \to \tau^+\tau^- \to (l^\pm\nu\bar{\nu}) (\pi^\mp\pi^0\nu) and e+eτ+τ(π±π0νˉ)(ππ0ν)e^+e^- \to \tau^+\tau^- \to (\pi^\pm\pi^0\bar{\nu}) (\pi^\mp\pi^0\nu), and the determined sign of hντh_{\nu_\tau}, the combined result of the three samples is: ρ=0.747±0.010±0.006\rho = 0.747\pm 0.010\pm 0.006, ξ=1.007±0.040±0.015\xi = 1.007\pm 0.040\pm 0.015, ξδ=0.745±0.026±0.009\xi\delta = 0.745\pm 0.026\pm 0.009, and hντ=0.995±0.010±0.003h_{\nu_\tau} = -0.995\pm 0.010\pm 0.003. The results are in agreement with the Standard Model V-A interaction.Comment: 18 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Search for charged Higgs decays of the top quark using hadronic tau decays

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    We present the result of a search for charged Higgs decays of the top quark, produced in ppˉp\bar{p} collisions at s=\surd s = 1.8 TeV. When the charged Higgs is heavy and decays to a tau lepton, which subsequently decays hadronically, the resulting events have a unique signature: large missing transverse energy and the low-charged-multiplicity tau. Data collected in the period 1992-1993 at the Collider Detector at Fermilab, corresponding to 18.7±\pm0.7~pb1^{-1}, exclude new regions of combined top quark and charged Higgs mass, in extensions to the standard model with two Higgs doublets.Comment: uuencoded, gzipped tar file of LaTeX and 6 Postscript figures; 11 pp; submitted to Phys. Rev.

    Inclusive jet cross section in pˉp{\bar p p} collisions at s=1.8\sqrt{s}=1.8 TeV

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    The inclusive jet differential cross section has been measured for jet transverse energies, ETE_T, from 15 to 440 GeV, in the pseudorapidity region 0.1η\leq | \eta| \leq 0.7. The results are based on 19.5 pb1^{-1} of data collected by the CDF collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton distribution functions. The cross section for jets with ET>200E_T>200 GeV is significantly higher than current predictions based on O(αs3\alpha_s^3) perturbative QCD calculations. Various possible explanations for the high-ETE_T excess are discussed.Comment: 8 pages with 2 eps uu-encoded figures Submitted to Physical Review Letter

    Measurement of Dijet Angular Distributions at CDF

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    We have used 106 pb^-1 of data collected in proton-antiproton collisions at sqrt(s)=1.8 TeV by the Collider Detector at Fermilab to measure jet angular distributions in events with two jets in the final state. The angular distributions agree with next to leading order (NLO) predictions of Quantum Chromodynamics (QCD) in all dijet invariant mass regions. The data exclude at 95% confidence level (CL) a model of quark substructure in which only up and down quarks are composite and the contact interaction scale is Lambda_ud(+) < 1.6 TeV or Lambda_ud(-) < 1.4 TeV. For a model in which all quarks are composite the excluded regions are Lambda(+) < 1.8 TeV and Lambda(-) < 1. 6 TeV.Comment: 16 pages, 2 figures, 2 tables, LaTex, using epsf.sty. Submitted to Physical Review Letters on September 17, 1996. Postscript file of full paper available at http://www-cdf.fnal.gov/physics/pub96/cdf3773_dijet_angle_prl.p

    Search for New Particles Decaying to Dijets at CDF

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    We have used 106 pb^-1 of data collected with the Collider Detector at Fermilab to search for new particles decaying to dijets. We exclude at the 95% confidence level models containing the following new particles: axigluons and flavor universal colorons with mass between 200 and 980 GeV/c, excited quarks with mass between 80 and 570 GeV/c^2 and between 580 and 760 GeV/c^2, color octet technirhos with mass between 260 and 480 GeV/c^2, W' bosons with mass between 300 and 420 GeV/c^2, and E_6 diquarks with mass between 290 and 420 GeV/c^2.Comment: 18 pages, 4 figures, 1 table. Submitted to Physical Review D Rapid Communications. Postscript file of paper is also available at http://www-cdf.fnal.gov/physics/pub97/cdf3276_dijet_search_prd_rc.p

    A proposal for a coordinated effort for the determination of brainwide neuroanatomical connectivity in model organisms at a mesoscopic scale

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    In this era of complete genomes, our knowledge of neuroanatomical circuitry remains surprisingly sparse. Such knowledge is however critical both for basic and clinical research into brain function. Here we advocate for a concerted effort to fill this gap, through systematic, experimental mapping of neural circuits at a mesoscopic scale of resolution suitable for comprehensive, brain-wide coverage, using injections of tracers or viral vectors. We detail the scientific and medical rationale and briefly review existing knowledge and experimental techniques. We define a set of desiderata, including brain-wide coverage; validated and extensible experimental techniques suitable for standardization and automation; centralized, open access data repository; compatibility with existing resources, and tractability with current informatics technology. We discuss a hypothetical but tractable plan for mouse, additional efforts for the macaque, and technique development for human. We estimate that the mouse connectivity project could be completed within five years with a comparatively modest budget.Comment: 41 page

    The Pathway to Detangle a Scrambled Gene

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    Programmed DNA elimination and reorganization frequently occur during cellular differentiation. Development of the somatic macronucleus in some ciliates presents an extreme case, involving excision of internal eliminated sequences (IESs) that interrupt coding DNA segments (macronuclear destined sequences, MDSs), as well as removal of transposon-like elements and extensive genome fragmentation, leading to 98% genome reduction in Stylonychia lemnae. Approximately 20-30% of the genes are estimated to be scrambled in the germline micronucleus, with coding segment order permuted and present in either orientation on micronuclear chromosomes. Massive genome rearrangements are therefore critical for development.To understand the process of DNA deletion and reorganization during macronuclear development, we examined the population of DNA molecules during assembly of different scrambled genes in two related organisms in a developmental time-course by PCR. The data suggest that removal of conventional IESs usually occurs first, accompanied by a surprising level of error at this step. The complex events of inversion and translocation seem to occur after repair and excision of all conventional IESs and via multiple pathways.This study reveals a temporal order of DNA rearrangements during the processing of a scrambled gene, with simpler events usually preceding more complex ones. The surprising observation of a hidden layer of errors, absent from the mature macronucleus but present during development, also underscores the need for repair or screening of incorrectly-assembled DNA molecules
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