Virtual Photon Structure from Jet Production at HERA

The feasibility of measuring parton distribution functions of of virtual photons via the jet production at HERA is investigated.Comment: Contribution to the Workshop on "Future Physics at HERA", eds. G. Ingelman, A. De Roeck, R. Klanner,4 pages, 3 figures, epsfi

Real and virtual photon structure from dijet events

Jet production in $ep$ collisions is sensitive to the partonic structure of photon. The latest measurements of dijet production from the H1 experiment provide new results of the gluon density of real photons at low $x$ and, for the first time, on the partonic density of virtual photons. Properties of the photon remnant were measured as a function of the hard scale defined by the $p_T$ of the jets. The comparison of dijet cross sections with the NLO QCD calculation shows the non-triviality of the concept of virtual photon structure.Comment: 4 pages, Latex with 4 ps figures, references for section 5 updated, Talk presented at DIS99 Workshop at Zeuthen, April 199

SiPM Gain Stabilization Studies for Adaptive Power Supply

We present herein gain stabilization studies of SiPMs using a climate chamber at CERN. We present results for four detectors not tested before, three from Hamamatsu and one from KETEK. Two of the Hamamatsu SiPMs are novel sensors with trenches that reduce cross talk. We use an improved readout system with a digital oscilloscope controlled with a dedicated LabView program. We improved and automized the analysis to deal with large datasets. We have measured the gain-versus-bias-voltage dependence at fixed temperature and gain-versus-temperature dependence at fixed bias voltage to determine the bias voltage dependence on temperature $V(T)$ for stable gain. We show that the gain remains stable to better than $\pm 0.5\%$ in the $20^\circ \rm C - 30^\circ C$ temperature range if the bias voltage is properly adjusted with temperature.Comment: 14 pages, 41 figures, Talk presented at the International Workshop on Future Linear Colliders (LCWS15), Whistler, Canada, 2-6 November 201

QCD Analysis of Dijet Production at Low {\boldmath Q2Q^2} at HERA

Recent H1 data on triple differential dijet cross sections in $e^\pm p$ interactions in the region of low photon virtualities are shown to be in reasonable agreement with the predictions of the NLO QCD calculations obtained using the program NLOJET++. The implications of this observation for the phenomenological relevance of the concept of resolved virtual photon are discussed.Comment: 5 pages, 3 figure

Comprehensive Review Of Current Endodontic Sealers

Endodontic sealers for non-surgical root canal treatment (NSRCT) span many compositions and attributes. This comprehensive review discusses current types of endodontic sealers by their setting reaction type, composition, and properties: zinc oxide-eugenol, salicylate, fatty acid, glass ionomer, silicone, epoxy resin, tricalcium silicate, and methacrylate resin sealers. Setting time, solubility, sealing ability, antimicrobial, biocompatibility, and cytotoxicity are all aspects key to the performance of endodontic sealers. Because sealing ability is so important to successful outcomes, the relative degree of microleakage among all the relevant sealers was calculated by way of a meta-analysis of relevant literature. Compared to AH Plus, tricalcium silicate sealers show the lowest relative microleakage among the sealers assessed, followed by silicone sealers and other non-AH Plus epoxy resin sealers. Tricalcium silicate sealers also exhibit the most favorable antimicrobial effect and excellent biocompatibility. Future sealers developed should ideally combine a hermetic seal with therapeutic effects