Mary’s Dilemma: A Novel Take On Jackson’s Famous Thought Experiment

This paper explores and evaluates the famous Mary case put forward by Frank Jackson in support of what he calls the knowledge argument against physicalism. After laying out Jackson’s position, I set out to determine whether certain previous physicalist attempts at undermining it have been successful. Finding that they have not, I use their shortcomings to inform the construction of a new position, one which I argue renders the Mary case at odds with itself and frees physicalism from the knowledge argument’s grasp

Development of spinning-disk solid sample delivery system forhigh-repetition rate x-ray free electron laser experiments

X-ray free electron lasers (XFELs) can deliver trains of x-ray pulses that have extreme peak power of more than 1020W/cm2 and pulse spacings as short as tens of nanoseconds.Such x-ray pulses destroy the samples in a single shotby Coulomb explosion, forming a hot plasma or crateraround the impact of the x-ray pulse in case of liquids orsolids. While the < 10 femtoseconds (fs) pulse durationallows for interrogation of the intact sample before thisdestruction sets in (probe-before-destroy), the sample hasto be replaced very quickly, before the arrival of the nextpulse. For lower repetition rates, this is currently donewith jets or droplet injectors for liquid samples, and forsolid samples with motorized linear translation. At veryhigh repetition rates, these approaches become extremelychallenging. Even though the beam size can be very small(<1 μm), the effect from the explosion and the resultingcrater or plasma might extend to tens of 10 μms. For ex-ample, a 100 ns time spacing between pulses requires aspeed of 100 m/s to move the sample by 10 μm. Here, wedescribe the development and characterization of a systemto continuously deliver a solid sample to the x-ray interac-tion point, using a spinning disk that can rotate at veryhigh speeds. We have tested our system at the LCLS andEuropean XFEL hard x-ray nano-focusing beamlines andemployed it for delivering the copper foil gain medium forstimulated x-ray emission in tests for the proposed X-raylaser oscillator (XLO)

Species of Dickeya and Pectobacterium Isolated during an Outbreak of Blackleg and Soft Rot of Potato in Northeastern and North Central United States

An outbreak of bacterial soft rot and blackleg of potato has occurred since 2014 with the epicenter being in the northeastern region of the United States. Multiple species of Pectobacterium and Dickeya are causal agents, resulting in losses to commercial and seed potato production over the past decade in the Northeastern and North Central United States. To clarify the pathogen present at the outset of the epidemic in 2015 and 2016, a phylogenetic study was made of 121 pectolytic soft rot bacteria isolated from symptomatic potato; also included were 27 type strains of Dickeya and Pectobacterium species, and 47 historic reference strains. Phylogenetic trees constructed based on multilocus sequence alignments of concatenated dnaJ, dnaX and gyrB fragments revealed the epidemic isolates to cluster with type strains of D. chrysanthemi, D. dianthicola, D. dadantii, P. atrosepticum, P. brasiliense, P. carotovorum, P. parmentieri, P. polaris, P. punjabense, and P. versatile. Genetic diversity within D. dianthicola strains was low, with one sequence type (ST1) identified in 17 of 19 strains. Pectobacterium parmentieri was more diverse, with ten sequence types detected among 37 of the 2015–2016 strains. This study can aid in monitoring future shifts in potato soft rot pathogens within the U.S. and inform strategies for disease management

A search for bottom-type vector-like quark pair production in dileptonic and fully hadronic final states in proton-proton collisions at s\sqrt{s} = 13 TeV

International audienceA search is described for the production of a pair of bottom-type vector-like quarks (B VLQs) with mass greater than 1000 GeV. Each B VLQ decays into a b quark and a Higgs boson, a b quark and a Z boson, or a t quark and a W boson. This analysis considers both fully hadronic final states and those containing a charged lepton pair from a Z boson decay. The products of the H $to$ bb boson decay and of the hadronic Z or W boson decays can be resolved as two distinct jets or merged into a single jet, so the final states are classified by the number of reconstructed jets. The analysis uses data corresponding to an integrated luminosity of 138 fb$^{-1}$ collected in proton-proton collisions at $\sqrt{s}$ = 13 TeV with the CMS detector at the LHC from 2016 to 2018. No excess over the expected background is observed. Lower limits are set on the B VLQ mass at 95% confidence level. These depend on the B VLQ branching fractions and are 1570 and 1540 GeV for 100% B $\to$ bH and 100% B $\to$ bZ, respectively. In most cases, the mass limits obtained exceed previous limits by at least 100 GeV

Search for long-lived particles using out-of-time trackless jets in proton-proton collisions at s \sqrt{s} = 13 TeV

A search for long-lived particles decaying in the outer regions of the CMS silicon tracker or in the calorimeters is presented. The search is based on a data sample of proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded with the CMS detector at the LHC in 2016–2018, corresponding to an integrated luminosity of 138 fb$^{−1}$. A novel technique, using nearly trackless and out-of-time jet information combined in a deep neural network discriminator, is employed to identify decays of long-lived particles. The results are interpreted in a simplified model of chargino-neutralino production, where the neutralino is the next-to-lightest supersymmetric particle, is long-lived, and decays to a gravitino and either a Higgs or Z boson. This search is most sensitive to neutralino proper decay lengths of approximately 0.5 m, for which masses up to 1.18 TeV are excluded at 95% confidence level. The current search is the best result to date in the mass range from the kinematic limit imposed by the Higgs boson mass up to 1.8 TeV.[graphic not available: see fulltext