What is the nature of morality? A response to Casebeer, Railton and Ruse

A response to comments by William Casebeer, Peter Railton, and Michael Ruse on "Naturalizing Ethics" (2007)

Folk moral relativism

It has often been suggested that people’s ordinary folk understanding of morality involves a rejection of moral relativism and a belief in objective moral truths. The results of six studies call this claim into question. Participants did offer apparently objectivist intuitions when confronted with questions about individuals from their own culture, but they offered increasingly relativist intuitions as they were confronted with questions about individuals from increasingly different cultures or ways of life. In light of these data, the authors hypothesize that people do not have a fixed commitment to moral objectivism but instead tend to adopt different views depending on the degree to which they consider radically different perspectives on moral questions. [NOTE: This is a reprint of Sarkissian et al 2011

Solving nonlinear multicommodity flow problems by the analytic center cutting plane method

The paper deals with nonlinear multicommodity flow problems with convex costs. A decomposition method is proposed to solve them. The approach applies a potential reduction algorithm to solve the master problem approximately and a column generation technique to define a sequence of primal linear programming problems. Each subproblem consists of finding a minimum cost flow between an origin and a destination node in an uncapacited network. It is thus formulated as a shortest path problem and solved with Dijkstra's d-heap algorithm. An implementation is described that takes full advantage of the supersparsity of the network in the linear algebra operations. Computational results show the efficiency of this approach on well-known nondifferentiable problems and also large scale randomly generated problems (up to 1000 arcs and 5000 commodities

Canonical quantization of the WZW model with defects and Chern-Simons theory

We perform canonical quantization of the WZW model with defects and permutation branes. We establish symplectomorphism between phase space of WZW model with $N$ defects on cylinder and phase space of Chern-Simons theory on annulus times $R$ with $N$ Wilson lines, and between phase space of WZW model with $N$ defects on strip and Chern-Simons theory on disc times $R$ with $N+2$ Wilson lines. We obtained also symplectomorphism between phase space of the $N$-fold product of the WZW model with boundary conditions specified by permutation branes, and phase space of Chern-Simons theory on sphere with $N$ holes and two Wilson lines.Comment: 26 pages, minor corrections don

Market and regional segmentation and risk premia in the first era of financial globalization

We study market segmentation effects using data on U.S. railroads that list their bonds in New York and London between 1873 and 1913. This sample provides a unique setting for such analysis because of the precision offered by bond yields in cost of capital estimation, the geography-specific nature of railroad assets, and ongoing substantial technological change. We document a significant reduction in market segmentation over time. Whilst New York bond yields exceeded those in London in the 1870s, this premium disappeared by the early 1900s. However, the segmentation premium persisted in the more remote regions of the United States.Chambers acknowledges financial support from his Keynes Fellowship, the Newton Centre for Endowment Asset Management and the Cambridge Endowment for Research in Finance, Sarkissian acknowledges financial support from the Social Sciences & Humanities Research Council of Canada, and Schill acknowledges financial support from the Darden School Foundation

Radio disappearance of the magnetar XTE J1810-197 and continued X-ray timing

We report on timing, flux density, and polarimetric observations of the transient magnetar and 5.54 s radio pulsar XTE J1810-197 using the GBT, Nancay, and Parkes radio telescopes beginning in early 2006, until its sudden disappearance as a radio source in late 2008. Repeated observations through 2016 have not detected radio pulsations again. The torque on the neutron star, as inferred from its rotation frequency derivative f-dot, decreased in an unsteady manner by a factor of 3 in the first year of radio monitoring. In contrast, during its final year as a detectable radio source, the torque decreased steadily by only 9%. The period-averaged flux density, after decreasing by a factor of 20 during the first 10 months of radio monitoring, remained steady in the next 22 months, at an average of 0.7+/-0.3 mJy at 1.4 GHz, while still showing day-to-day fluctuations by factors of a few. There is evidence that during this last phase of radio activity the magnetar had a steep radio spectrum, in contrast to earlier behavior. There was no secular decrease that presaged its radio demise. During this time the pulse profile continued to display large variations, and polarimetry indicates that the magnetic geometry remained consistent with that of earlier times. We supplement these results with X-ray timing of the pulsar from its outburst in 2003 up to 2014. For the first 4 years, XTE J1810-197 experienced non-monotonic excursions in f-dot by at least a factor of 8. But since 2007, its f-dot has remained relatively stable near its minimum observed value. The only apparent event in the X-ray record that is possibly contemporaneous with the radio shut-down is a decrease of ~20% in the hot-spot flux in 2008-2009, to a stable, minimum value. However, the permanence of the high-amplitude, thermal X-ray pulse, even after the radio demise, implies continuing magnetar activity.Comment: ApJ, accepted, 12 pages, 9 figure

Spin-down evolution and radio disappearance of the magnetar PSR J1622−-4950

We report on 2.4 yr of radio timing measurements of the magnetar PSR J1622$-$4950 using the Parkes telescope, between 2011 November and 2014 March. During this period the torque on the neutron star (inferred from the rotational frequency derivative) varied greatly, though much less erratically than in the 2 yr following its discovery in 2009. During the last year of our measurements the frequency derivative decreased in magnitude monotonically by 20\%, to a value of $-1.3\times10^{-13}$ s$^{-2}$, a factor of 8 smaller than when discovered. The flux density continued to vary greatly during our monitoring through 2014 March, reaching a relatively steady low level after late 2012. The pulse profile varied secularly on a similar timescale as the flux density and torque. A relatively rapid transition in all three properties is evident in early 2013. After PSR J1622$-$4950 was detected in all of our 87 observations up to 2014 March, we did not detect the magnetar in our resumed monitoring starting in 2015 January and have not detected it in any of the 30 observations done through 2016 September.Comment: 8 pages, 5 figures, submitted to Ap

PSC and volcanic aerosol routine observations in Antarctica by UV-visible ground-based spectrometry

Polar statospheric clouds (PSC) and stratospheric aerosol can be observed by ground-based UV-visible spectrometry by looking at the variation of the color of the sky during twilight. A radiative transfer model shows that reddenings are caused by high altitude (22-28 km) thin layers of scatterers, while low altitude (12-20 km) thick ones result in blueings. The color index method applied on 4 years of observations at Dumont d'Urville (67 deg S), from 1988 to 1991, shows that probably because the station is located at the edge of the vortex, dense PSC are uncommon. More unexpected is the existence of a systematic seasonal variation of the color of the twilight sky - bluer at spring - which reveals the formation of a dense scattering layer at or just above the tropopause at the end of the winter. Large scattering layers are reported above the station in 1991, first in August around 12-14 km, later in September at 22-24 km. They are attributed to volcanic aerosol from Mt Hudson and Mt Pinatubo respectively, which erupted in 1991. Inspection of the data shows that the lowest entered rapidly into the polar vortex but not the highest which remained outside, demonstrating that the vortex was isolated at 22-26 km

Peculiar Spin Frequency and Radio Profile Evolution of PSR J1119−-6127 Following Magnetar-like X-ray Bursts

We present the spin frequency and profile evolution of the radio pulsar J1119$-$6127 following magnetar-like X-ray bursts from the system in 2016 July. Using data from the Parkes radio telescope, we observe a smooth and fast spin-down process subsequent to the X-ray bursts resulting in a net change in the pulsar rotational frequency of $\Delta\nu\approx-4\times10^{-4}$\,Hz. During the transition, a net spin-down rate increase of $\Delta\dot\nu\approx-1\times10^{-10}$\,Hz\,s$^{-1}$ is observed, followed by a return of $\dot{\nu}$ to its original value. In addition, the radio pulsations disappeared after the X-ray bursts and reappeared about two weeks later with the flux density at 1.4\,GHz increased by a factor of five. The flux density then decreased and undershot the normal flux density followed by a slow recovery back to normal. The pulsar's integrated profile underwent dramatic and short-term changes in total intensity, polarization and position angle. Despite the complex evolution, we observe correlations between the spin-down rate, pulse profile shape and radio flux density. Strong single pulses have been detected after the X-ray bursts with their energy distributions evolving with time. The peculiar but smooth spin frequency evolution of PSR~J1119$-$6127 accompanied by systematic pulse profile and flux density changes are most likely to be a result of either reconfiguration of the surface magnetic fields or particle winds triggered by the X-ray bursts. The recovery of spin-down rate and pulse profile to normal provides us the best case to study the connection between high magnetic-field pulsars and magnetars.Comment: Accepted for publication in MNRAS on 2018 July 2