Laser diagnostics and minor species detection in combustion using resonant four-wave mixing

Peer reviewedPostprin

Renegado: Immigrant Identities and Aspirations of White Muslim Converts in Morocco

If one turns over enough stones in Morocco, they will come across hundreds of Western converts to Islam, most of whom are white. Some are obvious: one might spot a blue-eyed Belgian wearing a jellaba on a train to Fes or a Danish woman in a hijab running a bakery in central Casablanca. Others might be mistaken for tourists, like an American woman with her hair pulled back into a ponytail seated in the corner of a high-end café in Rabat. These converts are immigrants, and most chose to live in Morocco as a form of hijra, or migration for religious purposes. Rather than a full anthropological research paper, I have elected to present my ISP as a podcast. Career aspirations and personal preferences aside, the podcast format is particularly well-suited to personal narratives, and consequently well-suited to my research. This ISP investigates how and why these white converts chose to build their lives in Morocco, and ultimately how their relationships to both their homelands and Morocco developed once they arrived. I conducted interviews with eight white converts from both Europe and North America. Among them were a Belgian military veteran and Salafi convert planning his hijra, two American Sufis who have run language schools in Morocco for decades, and a journalist who was introduced to Islam while in Tangier with his fellow beatniks in the early 1960s. I also spoke with the Moroccan-born and -raised daughter of two American Sufis, two Dutch anthropologists who specialize in the hijra of converts, two Moroccan Islamic studies professors with knowledge of Moroccan attitudes towards converts, and the Moroccan descendant of a Portuguese pirate and convert to Islam in the 18th century. Some elements of the story are drawn from anthropological research on white convert identity and conversion in Morocco, and particularly the presence of pirate converts in Rabat and Sale in the 17th-early 19th centuries. My work draws upon the personal narratives of many of my interviewees – and, in a few cases, the academic work of my interviewees – to illustrate the innumerable complexities and nuances of life as a white convert immigrant in Morocco. When presented together, these narratives reveal white convert immigrants to be both perpetually foreign and privileged by their whiteness, a status that they pass on to their Moroccan-born descendants. Their relationships with their new country appear to be based primarily upon their expectations of Morocco prior to their decision to immigrate, not upon opinions they developed in Morocco

Testosterone affects song modulation during simulated territorial intrusions in male black redstarts (Phoenicurus ochruros)

Although it has been suggested that testosterone plays an important role in resource allocation for competitive behavior, details of the interplay between testosterone, territorial aggression and signal plasticity are largely unknown. Therefore, we investigated if testosterone acts specifically on signals that communicate the motivation or ability of individuals to engage in competitive situations in a natural context. We studied the black redstart, a territorial songbird species, during two different life-cycle stages, the early breeding phase in spring and the non-breeding phase in fall. Male territory holders were implanted with the androgen receptor blocker flutamide (Flut) and the aromatase inhibitor letrozole (Let) to inhibit the action of testosterone and its estrogenic metabolites. Controls received a placebo treatment. Three days after implantation birds were challenged with a simulated territorial intrusion (STI). Song was recorded before, during and after the challenge. In spring, both treatment groups increased the number of elements sung in parts of their song in response to the STI. However, Flut/Let-implanted males reacted to the STI with a decreased maximum acoustic frequency of one song part, while placebo-implanted males did not. Instead, placebo-implanted males sang the atonal part of their song with a broader frequency range. Furthermore, placebo-, but not Flut/Let-implanted males, sang shorter songs with shorter pauses between parts in the STIs. During simulated intrusions in fall, when testosterone levels are naturally low in this species, males of both treatment groups sang similar to Flut/Let-implanted males during breeding. The results suggest that song sung during a territorial encounter is of higher competitive value than song sung in an undisturbed situation and may, therefore, convey information about the motivation or quality of the territory holder. We conclude that testosterone facilitates context-dependent changes in song structures that may be honest signals of male quality in black redstarts

On the Size of Finite Rational Matrix Semigroups

Let $n$ be a positive integer and $\mathcal M$ a set of rational $n \times n$-matrices such that $\mathcal M$ generates a finite multiplicative semigroup. We show that any matrix in the semigroup is a product of matrices in $\mathcal M$ whose length is at most $2^{n (2 n + 3)} g(n)^{n+1} \in 2^{O(n^2 \log n)}$, where $g(n)$ is the maximum order of finite groups over rational $n \times n$-matrices. This result implies algorithms with an elementary running time for deciding finiteness of weighted automata over the rationals and for deciding reachability in affine integer vector addition systems with states with the finite monoid property