Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Measurement of associated Z plus charm production in proton-proton collisions at root s=8TeV

A study of the associated production of a Z boson and a charm quark jet (Z + c), and a comparison to production with a b quark jet (Z + b), in pp collisions at a centre-of-mass energy of 8 TeV are presented. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 fb(-1), collected with the CMS detector at the CERN LHC. The Z boson candidates are identified through their decays into pairs of electrons or muons. Jets originating from heavy flavour quarks are identified using semileptonic decays of c or b flavoured hadrons and hadronic decays of charm hadrons. The measurements are performed in the kinematic region with two leptons with pT(l) > 20 GeV, vertical bar eta(l)vertical bar 25 GeV and vertical bar eta(jet)vertical bar Z + c + X) B(Z -> l(+)l(-)) = 8.8 +/- 0.5 (stat)+/- 0.6 (syst) pb. The ratio of the Z+c and Z+b production cross sections is measured to be sigma(pp -> Z+c+X)/sigma (pp -> Z+b+X) = 2.0 +/- 0.2 (stat)+/- 0.2 (syst). The Z+c production cross section and the cross section ratio are also measured as a function of the transverse momentum of theZ boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.Peer reviewe

Measurement of the underlying event activity in inclusive Z boson production in proton-proton collisions at root s=13 TeV

This paper presents a measurement of the underlying event activity in proton-proton collisions at a center-of-mass energy of 13TeV, performed using inclusive Z boson production events collected with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 2.1 fb(-1). The underlying event activity is quantified in terms of the charged particle multiplicity, as well as of the scalar sum of the charged particles' transverse momenta in different topological regions defined with respect to the Z boson direction. The distributions are unfolded to the stable particle level and compared with predictions from various Monte Carlo event generators, as well as with similar CDF and CMS measurements at center-of-mass energies of 1.96 and 7TeV respectively.Peer reviewe

Horizontal localization and hearing in noise ability in adults with sensorineural hearing loss using hearing aids with binaural processing

textThe purpose of the study was to determine whether hearing aids with binaural processing improve performance during a localization and a hearing in noise task. The study included 16 participants, ages 29 – 67, with bilateral, essentially symmetrical, sensorineural hearing loss who had no prior hearing aid experience. Participants were fit with Oticon Epoq XW hearing aids bilaterally and completed the localization and the hearing in noise task with three listening conditions: (1) without hearing aids (NO), (2) with hearing aids that were not linked (BIL), and (3) with hearing aids that were linked (BIN). For the localization task, 1.5 second pink noise bursts at 75 dB SPL were used as the stimulus. A 180° 11-speaker array was set up to the right or left side of the participants. A twelfth speaker on the contralateral side of the array introduced constant background pink noise at 65 dB SPL. Results revealed that participants performed the best with the NO condition, followed by BIL, then BIN. There was a significant difference between NO and BIL and NO and BIN. For the hearing in noise (HIN) task, sentences from the Hearing in Noise Test (HINT) were used as target stimuli. Continuous discourse by one male and two female talkers were used as maskers. There were four masker conditions for this task: (1) signal at 0°, masker at 90° (S0-N90), (2) signal at 0°, masker at 180° (S0-N180), (3) signal at 0°, masker at 270° (S0-N270), and (4) signal at 0°, maskers at 90°, 180°, and 270° (S0-N90, 180, 270). Results revealed that there was no significant difference between listening conditions when all masker conditions were considered. When the one-masker conditions were included, there was a significant difference between the NO and BIL and the NO and BIN conditions with the best performance for BIL, followed by BIN, then NO. Results also revealed a significant difference between masker conditions with the best performance for S0-N270, next best for S0-N90, followed by S0-N180, then S0-N90, 180, 270.Communication Sciences and Disorder