Study of Strangeness Photoproduction on the Neutron in the Threshold Region

Photoproduction of the neutral kaon on the deuteron has been investigated at the Research Center for Electron Photon Science, Tohoku University. We constructed the Neutral Kaon Spectrometer-2 for the detection of charged particles from the decay of the neutral kaon and the hyperon. We obtained a momentum distribution of K ⁰ with the inclusive measurement. It was consistent with the previous measurement. The total cross section of γ + d → K ⁰ + Λ + p was estimated from the measured integral cross section of γ + d → Λ + X. The total cross section with respect to the photon energy was compared with the theoretical calculations. It favored the Saclay-Lyon A model calculation with the ratio of the neutral to charged coupling constants of the axial-vector meson, K ₁, as ~ ?1.5. The energy dependence and the magnitude of the total cross section were similar to the total cross section of γ + p → K ⁺ Λ.     

Analyticity and the Deviant Logician: Williamson’s Argument from Disagreement

One way to discredit the suggestion that a statement is true just in virtue of its meaning is to observe that its truth is the subject of genuine disagreement. By appealing to the case of the unorthodox philosopher, Timothy Williamson has recast this response as an argument foreclosing any appeal to analyticity. Reconciling Quine’s epistemological holism with his treatment of the ‘deviant logician’, I show that we may discharge the demands of charitable interpretation even while attributing trivial semantic error to Williamson’s philosophers. Williamson’s effort to generalize the argument from disagreement therefore fails.     

Are Bare Particulars Constituents?

In this article I examine an as yet unexplored aspect of J.P. Moreland’s defense of so-called bare particularism — the ontological theory according to which ordinary concrete particulars (e.g., Socrates) contain bare particulars as individuating constituents and property ‘hubs.’ I begin with the observation that if there is a constituency relation obtaining between Socrates and his bare particular, it must be an internal relation, in which case the natures of the relata will necessitate the relation. I then distinguish various ways in which a bare particular might be thought to have a nature and show that on none of these is it possible for a bare particular to be a constituent of a complex particular. Thus, Moreland’s attempt to resurrect bare particulars as ontologically indispensable entities is not wholly without difficulties.     

Selfish routing in public services

It is well observed that individual behaviour can have an effect on the efficiency of queueing systems. The impact of this behaviour on the economic efficiency of public services is considered in this paper where we present results concerning the congestion related implications of decisions made by individuals when choosing between facilities. The work presented has important managerial implications at a public policy level when considering the effect of allowing individuals to choose between providers. We show that in general the introduction of choice in an already inefficient system will not have a negative effect. Introducing choice in a system that copes with demand will have a negative effect.     

On the time-dependent moments of Markovian queues with reneging

We give an explicit representation for the time-dependent moments of a Markovian queueing system with reneging. Our expressions are comparable in form to the moment expressions for the M/M/1 queue found in Abate and Whitt (Queueing Syst. 2:41–65, 1987; Adv. Appl. Probab. 20:145–178, 1988). We also illustrate how to use these expressions to derive analogous moment expressions for a reflected Ornstein–Uhlenbeck process, with reflection at zero.     

Selective C−H Functionalization of Methane and Ethane by a Molecular SbV Complex

Owing to the strong nonpolar bonds involved, selective C?H functionalization of methane and ethane to esters remains a challenge for molecular homogeneous chemistry. We report that the computationally predicted main‐group p‐block Sb^V(TFA)₅ complex selectively functionalizes the C?H bonds of methane and ethane to the corresponding mono and/or diol trifluoroacetate esters at 110–180 °C with yields for ethane of up to 60 % with over 90 % selectivity. Experimental and computational studies support a unique mechanism that involves Sb^V‐mediated C?H activation followed by functionalization of a Sb^V‐alkyl intermediate.     

Dual Gold‐Catalyzed Cycloaromatization of Unconjugated (E)‐Enediynes

A synthesis of unconjugated (E)‐enediynes from allenyl amino alcohols is reported and their gold‐catalyzed cascade cycloaromatization to a broad range of enantioenriched substituted isoindolinones has been developed. Experimental and computational studies support the reaction proceeding via a dual‐gold σ,π‐activation mode, involving a key gold‐vinylidene‐ and allenyl‐gold‐containing intermediate.     

Palladium‐Catalyzed Construction of Quaternary Stereocenters by Enantioselective Arylation of γ‐Lactams with Aryl Chlorides and Bromides

Herein, we report the first Pd‐catalyzed enantioselective arylation of α‐substituted γ‐lactams. Two sets of conditions were developed for this transformation, allowing for the use of either aryl chlorides or bromides as electrophiles. Utilizing a highly electron‐rich dialkylphosphine ligand we have been able to construct α‐quaternary centers in good yields (up to 91 % yield) and high enantioselectivities (up to 97 % ee).     

Simplicity Beneath Complexity: Counting Molecular Electrons Reveals Transients and Kinetics of Photodissociation Reactions

Time‐resolved pump–probe gas‐phase X‐ray scattering signals, extrapolated to zero momentum transfer, provide a measure of the number of electrons in a system, an effect that arises from the coherent addition of elastic scattering from the electrons. This allows to identify reactive transients and determine the chemical reaction kinetics without the need for extensive scattering simulations or complicated inversion of scattering data. We examine the photodissociation reaction of trimethylamine and identify two reaction paths upon excitation to the 3p state at 200 nm: a fast dissociation path out of the 3p state to the dimethyl amine radical (16.6±1.2 %) and a slower dissociation via internal conversion to the 3s state (83.4±1.2 %). The time constants for the two reactions are 640±130 fs and 74±6 ps, respectively. Additionally, it is found that the transient dimethyl amine radical has a N?C bond length of 1.45±0.02 Å and a C?N?C bond angle of 118°±4°.