About the Cover Art

I made this drawing in 2016 as cover for our prison newsletter. I have been in prison for many years. I wanted this drawing to be a metaphor of what I think is the usual relationship between prison staff and prisoners. The snake represents the prevailing justice system and how it works in jail. The snake disguises itself in the wall, always ready, sneaking in and out to look upon the prisoner and prey on him, but never in the open. The system always wants us to be responsible but simultaneously creates a completely impossible environment in which to show that responsibility, driving prisoners to absurd situations if they attempt to follow the rules and powerless to defend themselves from the results. The snake is still there today, but fortunately I keep it in the wall, away from me as much as possible. --Loco (M.B.

d-Wave Order Parameter in Bi2212 from a Phenomenological Model of High Tc_c Cuprates

A phenomenological lattice model of high $T_c$ cuprates including order parameter phase fluctuations is considered within the BCS approximation, to interpret the experimental data from ARPES measurements on Bi2212 samples. A Kosterlitz-Thouless (KT) transition temperature $T_c^{KT}$ is estimated below the mean field transition $T_c^{MF}$, phase boundaries between competing order parameters of different symmetries are obtained and best model parameters, fitting the ARPES gap of $d_{x^2-y^2}$ symmetry, are determined. Variation of $T_c^{KT}$, as a function of the dopant concentration $\delta$, is in qualitative agreement with experiments.Comment: Latex file, 11 output pages, 5 figures (available from the author on request

Transforming gender relations in rural Ethiopia through community conversations

Poster prepared for a share fair, Addis Ababa, May 201

Intrinsic optical dichroism in the chiral superconducting state of Sr2_{2}RuO4_{4}

We present an analysis of the Hall conductivity $\sigma_{xy}(\omega, T)$ in time reversal symmetry breaking states of exotic superconductors. We find that the dichroic signal is non-zero in systems with inter-band order parameters. This new intrinsic mechanism may explain the Kerr effect observed in strontium ruthenate and possibly other superconductors. We predict coherence factor effects in the temperature dependence of the imaginary part of the ac Hall conductivity $Im\sigma_{xy}(\omega, T)$, which can be tested experimentally.Comment: 4+ pages, 4 figures, published versio

Sherds bring happines:Evidence of deliberately broken pottery

A large part of the pottery in ritual deposits must have been broken deliberately, but deliberate breakage is difficult to distinguish from accidental breakage. This paper describes an experiment with fifteen handmade sherds without context information from the excavation in the terp of Ezinge (northern Netherlands). The sherds dated from between the 5th century BC and the 5th century AD. They were broken with the aid of various implements, similar to objects found during the excavation.Breaking the sherds demands considerable force. The usualdamage is a single, Y-shaped or, rarely, a more complex break with some damage at the point of impact. At the back, only breaks and rarely surface damage can be established. The use of an iron awl can be identified if the awl was placed obliquely on the surface. This position comes naturally if an awl was used to break a complete pot from above or from the inside. Exerting pressure, combined with a rotating movement, usually will cause a break. This method leaves characteristic indentations, which are regularly observed on the excavated pottery from Ezinge. The use of other implements leaves less clearly identifiabletraces of deliberate breakage

Freedom is a State of Mind

Artwork by Loco, an incarcerated artist at P.I. Neuwegein, The Netherlands

Luxury tableware? Terra sigillata in the coastal region of the northern Netherlands

With thousands of finds, Roman terra sigillata (TS) is a common find category in terp settlements of the Northern Netherlands. It is traditionally interpreted as luxury tableware of the local elites, who acquired it through their contacts with Romans, or who were able to buy it from traders who came to this area with their merchandise. This paper questions that interpretation. The reason is that the far majority of TS is found as sherds, which, despite their good recognisability, only rarely fit other sherds. Moreover, many of these sherds are worked or used in some way. They were made into pendants, spindle whorls and playing counters, or show traces of deliberate breakage and of use for unknown purposes. Such traces are found on 70–80% of the sherds. The meaning of TS hence seems to have been symbolic rather than functional. Rather than as luxury tableware, TS may have been valued for the sake of the material itself, and may have been imported as sherds rather than as complete vessels. A symbolic value also shows from its long-term use. Used or worked TS sherds from the 2nd and 3rd century AD are often found in finds assemblages that may be interpreted as ritual deposits, not only from the Roman Period but also from the early Middle Ages. There are striking parallels for such use in early modern colonial contexts. TS sherds may have been part of the diplomatic gifts by which the Romans attempted to keep peace north of the limes, or may even have been payments for local products. These sherds might thus be comparable to the trade beads of early-modern European colonial traders