The structure of blocks with a Klein four defect group

We prove Erdmann’s conjecture [16] stating that every block with a Klein four defect group has a simple module with trivial source, and deduce from this that Puig’s finiteness conjecture holds for source algebras of blocks with a Klein four defect group. The proof uses the classification of finite simple groups

Nationwide treatment and outcomes of intrahepatic cholangiocarcinoma

Background: Most data on the treatment and outcomes of intrahepatic cholangiocarcinoma (iCCA) derives from expert centers. This study aimed to investigate the treatment and outcomes of all patients diagnosed with iCCA in a nationwide cohort. Methods: Data on all patients diagnosed with iCCA between 2010 and 2018 were obtained from the Netherlands Cancer Registry. Results: In total, 1747 patients diagnosed with iCCA were included. Resection was performed in 292 patients (17%), 548 patients (31%) underwent palliative systemic treatment, and 867 patients (50%) best supportive care (BSC). The OS median and 1-, and 3-year OS were after resection: 37.5 months (31.0–44.0), 79.2%, and 51.6%,; with systemic therapy, 10.0 months (9.2–10.8), 38.4%, and 5.1%, and with BSC 2.2 months (2.0–2.5), 10.4%, and 1.3% respectively. The resection rate for patients who first presented in academic centers was 33% (96/292) compared to 13% (195/1454) in non-academic centers (P < 0.001). Discussion: Half of almost 1750 patients with iCCA over an 8 year period did not receive any treatment with a 1-year OS of 10.4%. Three-year survival was about 50% after resection, while long-term survival was rare after palliative treatment. The resection rate was higher in academic centers compared to non-academic centers

National consensus on a new resectability classification for perihilar cholangiocarcinoma - A modified Delphi method

Background: Currently, no practical definition of potentially resectable, borderline or unresectable perihilar cholangiocarcinoma (pCCA) is available. Aim of this study was to define criteria to categorize patients for use in a future neoadjuvant or induction therapy study. Method: Using the modified DELPHI method, hepatobiliary surgeons from all tertiary referral centers in the Netherlands were invited to participate in this study. During five online meetings, predefined factors determining resectability and additional factors regarding surgical resectability and operability were discussed. Results: The five online meetings resulted in 52 statements. After two surveys, consensus was reached in 63% of the questions. The main consensus included a definition regarding potential resectability. 1) Clearly resectable: no vascular involvement (≤90°) of the future liver remnant (FLR) and expected feasibility of radical biliary resection. 2) Clearly unresectable: non-reconstructable venous and/or arterial involvement of the FLR or no feasible radical biliary resection. 3) Borderline resectable: all patients between clearly resectable and clearly unresectable disease. Conclusion: This DELPHI study resulted in a practical and applicable resectability, or more accurate, an explorability classification, which can be used to categorize patients for use in future neoadjuvant therapy studies.</p

Impact of Positive Lymph Nodes and Resection Margin Status on the Overall Survival of Patients with Resected Perihilar Cholangiocarcinoma: The ENSCCA Registry

Background: Lymph node metastasis and positive resection margins have been reported to be major determinants of overall survival (OS) and poor recurrence-free survival (RFS) for patients who underwent resection for perihilar cholangiocarcinoma (pCCA). However, the prognostic value of positive lymph nodes independently from resection margin status on OS has not been evaluated. Methods: From the European Cholangiocarcinoma (ENSCCA) registry, patients who underwent resection for pCCA between 1994 and 2021 were included in this retrospective cohort study. The primary outcome was OS stratified for resection margin and lymph node status. The secondary outcome was recurrence-free survival. Results: A total of 325 patients from 11 different centers and six European countries were included. Of these, 194 (59.7%) patients had negative resection margins. In 113 (34.8%) patients, positive lymph nodes were found. Lymph node status, histological grade, and ECOG performance status were independent prognostic factors for survival. The median OS for N0R0, N0R1, N+R0, and N+R1 was 38, 30, 18, and 12 months, respectively (p < 0.001). Conclusion: These data indicate that in the presence of positive regional lymph nodes, resection margin status does not determine OS or RFS in patients with pCCA. Achieving negative margins in patients with positive nodes should not come at the expense of more extensive surgery and associated higher mortality.The ENSCCA Registry is completely funded by the European Association for the Study of the Liver (EASL; Registry grant awards 2016 and 2019 to J.M.B.), Incyte Bioscience International Sàrl (grant award 2020 to J.M.B.) and European Union’s Horizon 2020 Research and Innovation Program (grant number 825510, ESCALON: to J.M.B. and A.L.)

Active Brownian Particles. From Individual to Collective Stochastic Dynamics

We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

Energy Flow in the Hadronic Final State of Diffractive and Non-Diffractive Deep-Inelastic Scattering at HERA

An investigation of the hadronic final state in diffractive and non--diffractive deep--inelastic electron--proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo --rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep--inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep--inelastic $ep$ scattering, in which a sizeable diffractive contribution is present because of non--perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description.Comment: 22 pages, latex, 6 Figures appended as uuencoded fil

A Search for Selectrons and Squarks at HERA

Data from electron-proton collisions at a center-of-mass energy of 300 GeV are used for a search for selectrons and squarks within the framework of the minimal supersymmetric model. The decays of selectrons and squarks into the lightest supersymmetric particle lead to final states with an electron and hadrons accompanied by large missing energy and transverse momentum. No signal is found and new bounds on the existence of these particles are derived. At 95% confidence level the excluded region extends to 65 GeV for selectron and squark masses, and to 40 GeV for the mass of the lightest supersymmetric particle.Comment: 13 pages, latex, 6 Figure

Low Q^2 Jet Production at HERA and Virtual Photon Structure

The transition between photoproduction and deep-inelastic scattering is investigated in jet production at the HERA ep collider, using data collected by the H1 experiment. Measurements of the differential inclusive jet cross-sections dsigep/dEt* and dsigmep/deta*, where Et* and eta* are the transverse energy and the pseudorapidity of the jets in the virtual photon-proton centre of mass frame, are presented for 0 < Q2 < 49 GeV2 and 0.3 < y < 0.6. The interpretation of the results in terms of the structure of the virtual photon is discussed. The data are best described by QCD calculations which include a partonic structure of the virtual photon that evolves with Q2.Comment: 20 pages, 5 Figure

Hadron Production in Diffractive Deep-Inelastic Scattering

Characteristics of hadron production in diffractive deep-inelastic positron-proton scattering are studied using data collected in 1994 by the H1 experiment at HERA. The following distributions are measured in the centre-of-mass frame of the photon dissociation system: the hadronic energy flow, the Feynman-x (x_F) variable for charged particles, the squared transverse momentum of charged particles (p_T^{*2}), and the mean p_T^{*2} as a function of x_F. These distributions are compared with results in the gamma^* p centre-of-mass frame from inclusive deep-inelastic scattering in the fixed-target experiment EMC, and also with the predictions of several Monte Carlo calculations. The data are consistent with a picture in which the partonic structure of the diffractive exchange is dominated at low Q^2 by hard gluons.Comment: 16 pages, 6 figures, submitted to Phys. Lett.

Measurement of D* Meson Cross Sections at HERA and Determination of the Gluon Density in the Proton using NLO QCD

With the H1 detector at the ep collider HERA, D* meson production cross sections have been measured in deep inelastic scattering with four-momentum transfers Q^2>2 GeV2 and in photoproduction at energies around W(gamma p)~ 88 GeV and 194 GeV. Next-to-Leading Order QCD calculations are found to describe the differential cross sections within theoretical and experimental uncertainties. Using these calculations, the NLO gluon momentum distribution in the proton, x_g g(x_g), has been extracted in the momentum fraction range 7.5x10^{-4}< x_g <4x10^{-2} at average scales mu^2 =25 to 50 GeV2. The gluon momentum fraction x_g has been obtained from the measured kinematics of the scattered electron and the D* meson in the final state. The results compare well with the gluon distribution obtained from the analysis of scaling violations of the proton structure function F_2.Comment: 27 pages, 9 figures, 2 tables, submitted to Nucl. Phys.