Militantly ‘studying up’?: (ab)using whiteness for oppositional research

This paper develops the idea of militantly ‘studying up’. Through a discussion of research into the relationship between migrants and social/labour movements in Buenos Aires, Argentina, it explores the way in which my positionality both helped and hindered the (militant) research process. As the possibility for militant research seemed to recede, by interrogating the antagonisms bound up in the disjuncture between my perceived and my performed positionality, I was able to retain a commitment to militant research/research militancy. The movement to a form of oppositional (auto)ethnography was underpinned by an (ab)use of my whiteness. This touched on new possibilities for militant research, and also afforded further reflection on the structuring power of whiteness itself. Situating itself against-and-beyond discussions of militant research, this paper explores not only the rich potential but also the difficulties and limitations of such a methodology. In this regard it foregrounds discussion of failure as a key reflexive strategy. Ultimately it argues that there is potentially value in ‘studying up’ within militant (migration) research, but that concerns surround the (re-)reification of the very identities and structures that are intended to be deconstructed

CtIP Maintains Stability at Common Fragile Sites and Inverted Repeats by End Resection-Independent Endonuclease Activity

Chromosomal rearrangements often occur at genomic loci with DNA secondary structures, such as common fragile sites (CFSs) and palindromic repeats. We developed assays in mammalian cells that revealed CFS-derived AT-rich sequences and Alu inverted repeats (Alu-IRs) are mitotic recombination hotspots, requiring the repair functions of CtIP and the Mre11/Rad50/Nbs1 complex (MRN). We also identified an endonuclease activity of CtIP which is dispensable for end resection and homologous recombination (HR) at I-SceI-generated "clean" double-strand breaks (DSBs), but is required for repair of DSBs occurring at CFS-derived AT-rich sequences. In addition, CtIP nuclease defective mutants are impaired in Alu-IRs-induced mitotic recombination. These studies suggest that an end resection-independent CtIP function is important for processing DSB ends with secondary structures to promote HR. Furthermore, our studies uncover an important role of MRN, CtIP and their associated nuclease activities in protecting CFSs in mammalian cells

Reproducibility of CRISPR-Cas9 methods for generation of conditional mouse alleles: a multi-center evaluation

BackgroundCRISPR-Cas9 gene-editing technology has facilitated the generation of knockout mice, providing an alternative to cumbersome and time-consuming traditional embryonic stem cell-based methods. An earlier study reported up to 16% efficiency in generating conditional knockout (cKO or floxed) alleles by microinjection of 2 single guide RNAs (sgRNA) and 2 single-stranded oligonucleotides as donors (referred herein as “two-donor floxing” method).ResultsWe re-evaluate the two-donor method from a consortium of 20 laboratories across the world. The dataset constitutes 56 genetic loci, 17,887 zygotes, and 1718 live-born mice, of which only 15 (0.87%) mice contain cKO alleles. We subject the dataset to statistical analyses and a machine learning algorithm, which reveals that none of the factors analyzed was predictive for the success of this method. We test some of the newer methods that use one-donor DNA on 18 loci for which the two-donor approach failed to produce cKO alleles. We find that the one-donor methods are 10- to 20-fold more efficient than the two-donor approach.ConclusionWe propose that the two-donor method lacks efficiency because it relies on two simultaneous recombination events in cis, an outcome that is dwarfed by pervasive accompanying undesired editing events. The methods that use one-donor DNA are fairly efficient as they rely on only one recombination event, and the probability of correct insertion of the donor cassette without unanticipated mutational events is much higher. Therefore, one-donor methods offer higher efficiencies for the routine generation of cKO animal models

Major results from the first plasma campaign of the Wendelstein 7-X stellarator

After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreed for the limiter configuration employed during the first operational campaign. At power levels of 4 MW central electron densities reached 3 1019 m-3, central electron temperatures reached values of 7 keV and ion temperatures reached just above 2 keV. Important physics studies during this first operational phase include a first assessment of power balance and energy confinement, ECRH power deposition experiments, 2nd harmonic O-mode ECRH using multi-pass absorption, and current drive experiments using electron cyclotron current drive. As in many plasma discharges the electron temperature exceeds the ion temperature significantly, these plasmas are governed by core electron root confinement showing a strong positive electric field in the plasma centre.Peer reviewe