57 research outputs found

    A Nonparametric Method for the Derivation of α/β Ratios from the Effect of Fractionated Irradiations

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    Multifractionation isoeffect data are commonly analysed under the assumption that cell survival determines the observed tissue or tumour response, and that it follows a linear-quadratic dose dependence. The analysis is employed to derive the α/β ratios of the linear-quadratic dose dependence, and different methods have been developed for this purpose. A common method uses the so-called Fe plot. A more complex but also more rigorous method has been introduced by Lam et al. (1979). Their method, which is based on numerical optimization procedures, is generalized and somewhat simplified in the present study. Tumour-regrowth data are used to explain the nonparametric procedure which provides α/β ratios without the need to postulate analytical expressions for the relationship between cell survival and regrowth delay

    Frobenius structures over Hilbert C*-modules

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    We study the monoidal dagger category of Hilbert C*-modules over a commutative C*-algebra from the perspective of categorical quantum mechanics. The dual objects are the finitely presented projective Hilbert C*-modules. Special dagger Frobenius structures correspond to bundles of uniformly finite-dimensional C*-algebras. A monoid is dagger Frobenius over the base if and only if it is dagger Frobenius over its centre and the centre is dagger Frobenius over the base. We characterise the commutative dagger Frobenius structures as finite coverings, and give nontrivial examples of both commutative and central dagger Frobenius structures. Subobjects of the tensor unit correspond to clopen subsets of the Gelfand spectrum of the C*-algebra, and we discuss dagger kernels.Comment: 35 page

    Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

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    Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

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    On the progenitor of binary neutron star merger GW170817

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    On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just ∼40 Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of ∼2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 at the time of the second supernova (SN). We generate simulated progenitor populations and follow the three-dimensional kinematic evolution from binary neutron star (BNS) birth to the merger time, accounting for pre-SN galactic motion, for considerably different input distributions of the progenitor mass, pre-SN semimajor axis, and SN-kick velocity. Though not considerably tight, we find these constraints to be comparable to those for Galactic BNS progenitors. The derived constraints are very strongly influenced by the requirement of keeping the binary bound after the second SN and having the merger occur relatively close to the center of the galaxy. These constraints are insensitive to the galaxy's star formation history, provided the stellar populations are older than 1 Gyr

    Charged-particle nuclear modification factors in PbPb and pPb collisions at √=sNN=5.02 TeV

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    The spectra of charged particles produced within the pseudorapidity window |η| < 1 at √ sNN = 5.02 TeV are measured using 404 µb −1 of PbPb and 27.4 pb−1 of pp data collected by the CMS detector at the LHC in 2015. The spectra are presented over the transverse momentum ranges spanning 0.5 < pT < 400 GeV in pp and 0.7 < pT < 400 GeV in PbPb collisions. The corresponding nuclear modification factor, RAA, is measured in bins of collision centrality. The RAA in the 5% most central collisions shows a maximal suppression by a factor of 7–8 in the pT region of 6–9 GeV. This dip is followed by an increase, which continues up to the highest pT measured, and approaches unity in the vicinity of pT = 200 GeV. The RAA is compared to theoretical predictions and earlier experimental results at lower collision energies. The newly measured pp spectrum is combined with the pPb spectrum previously published by the CMS collaboration to construct the pPb nuclear modification factor, RpA, up to 120 GeV. For pT > 20 GeV, RpA exhibits weak momentum dependence and shows a moderate enhancement above unity

    62 Skuteczność miejscowa przedoperacyjnej i pooperacyjnej radioterapii raka odbytnicy w odniesieniu do całkowitej dawki promieniowania i czasu leczenia promieniami

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    WstępOcena skuteczności miejscowej przedoperacyjnej i pooperacyjnej radioterapii raka odbytnicy jest przedmiotem kontrowersji. Brak jest kontrolowanych badań klinicznych pozwalających w bezpośredni sposób porównać skuteczność miejscową obu tyehtych metod leczenia. W bieżącej pracy porównano skuteczność miejscową radioterapii przedoperacyjnej i pooperacyjnej w sposób pośredni, a w oparciu o statyczną analizę 51 zbiorów danych z piśmiennictwa.Materiał i metodaW celu uzyskania możliwie najbardziej jednorodnego materiału pod względem klinicznym i metodycznym do analizy nie włączono opracowań, których obok radioterapii stosowano chemioterapię uzupełniającą. W oparciu o dane z piśmiennictwa wyznaczono wskaźniki zmniejszania ryzyka występowania wznów lokoregionalnych i analizowano zależność pomiędzy tym parametrem a stosowaną dawką promieniowania, czasem leczenie promieniami i typem radioterapii (przedoperacyjna lub pooperacyjna).WynikiWyniki analizy wskazują że dla zrównoważenia niekorzystnego skutku repopulacji komórek nowotworowych w trakcie cztero- do sześciotygodniowej przerwy pomiędzy leczeniem chirurgicznym a radioterapią pooperacyjną wymagane jest (w porównaniu z terapią przedoperacyjną) podniesienie całkowitej dawki promieniowania o około 8 Gy, to jest o około 0,2–0,3 Gy na każdy dzień przerwy. Dla zrównoważenia niekorzystnego skutku repopulacji komórek nowotworowych w trakcie przedlub pooperacyjnego leczenia promieniami wymagana jest dawka około 0,5 Gy/na dzień.WnioskiKomórki nowotworowe raka odbytnicy cechuje szybkie tempo repopulacji. Klinicznym odzwierciedleniem tego zjawiska jest większa skuteczność miejscowa radioterapii przedoperacyjnej w porównaniu do radioterapii pooperacyjnej. Wydłużenie całkowitego czasu uzupełniającej radioterapii raka odbytnicy wiąże się z pogorszeniem skuteczności miejscowej leczenia

    Personalized screening intervals for biomarkers using joint models for longitudinal and survival data

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    Screening and surveillance are routinely used in medicine for early detection of disease and close monitoring of progression. Motivated by a study of patients who received a human tissue valve in the aortic position, in this work we are interested in personalizing screening intervals for longitudinal biomarker measurements. Our aim in this paper is 2-fold: First, to appropriately select the model to use at the time point the patient was still event-free, and second, based on this model to select the optimal time point to plan the next measurement. To achieve these two goals, we combine information theory measures with optimal design concepts for the posterior predictive distribution of the survival process given the longitudinal history of the subject
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